Application of machine learning in key properties of medical metal materials / 中国组织工程研究

BACKGROUND:The combination of machine learning and medical metal materials can make up for the inefficiency and high cost of traditional experiments and computational simulations,and quickly and accurately predict the characteristics of metal materials by analyzing large amounts of data,optimize material design and performance,and improve the safety and efficiency of medical applications. OBJECTIVE:To summarize the research progress and shortcomings of machine learning in the characteristics of medical materials. METHODS:The first author searched CNKI,PubMed,X-MOL,and Web of Science databases by computer to search all relevant articles from January 2013 to April 2023.The Chinese search terms were"machine learning of medical metal materials,medical titanium alloy,medical magnesium alloy,medical metal material properties".The English search terms were"machine learning medical metal materials,medical stainless steel alloy,medical cobalt-chromium alloy,medical titanium alloy,medical magnesium alloy".Finally,70 relevant articles were included for a summary. RESULTS AND CONCLUSION:(1)The introduction of machine learning as a material design methodology has opened up new paradigms for material science research as the accessibility of large amounts of data generated by traditional experimental and computational simulation methods increases.(2)The machine learning workflow is divided into four main parts:data collection and preprocessing,feature engineering,model selection and training,and model evaluation,each of which is indispensable.(3)Medical metal materials are categorized into:stainless steel co-base alloys,cobalt-chromium alloys,titanium alloys,and magnesium alloys.For stainless steel co-base alloy,machine learning predicts its mechanical properties,to improve the generalization ability of machine learning.For cobalt-chromium alloy,machine learning predicts its mechanical properties,and it can conclude that cobalt-chromium alloy is the optimal material for hip implants.For titanium alloy,machine learning predicts its mechanical properties,and it can select the implant with the best mechanical properties.For magnesium alloy,machine learning predicts its corrosion resistance and mechanical properties;the ensemble model can accurately predict the mechanical properties of magnesium alloys,and the random forest model can predict the optimal elemental contents of magnesium alloys as vascular stents.(4)Machine learning has deficiencies in the field of medical materials.For example,the model is relatively lagging;the data failed to be standardized,and the generalization is low.To solve such problems,we should make full use of deep learning and segmentation algorithm technology,use unified standard data,and improve the model to increase the generalization ability.

Bioremediation of tannery wastewater using UV-treated bacteria in the free and immobilized form

Aims@#Heavy metals are significant environmental pollutants and toxic to life and chromium (Cr) (VI) is one of them being discharged in the environment due to many human activities. The leather industry uses Cr(VI) salt in the tanning process, which is discharged untreated and becomes a source of many diseases. The use of microbes to remove metals is a cost-effective and clean method. The present study aims to isolate local and native microbes for Cr(VI) removal from tannery wastewater and enhance their capacity to bioremediate the tannery wastewater. Further, efficiency in free and immobilized forms was also checked.@*Methodology and results@#Microbes were isolated from a local tannery wastewater outlet and after many rounds of minimum inhibitory concentration, and concentration of 500 µg/mL was found to be that concentration at which microbes could survive, above which they died. The sequencing of 16S rRNA and its analysis showed that it was closely related to Staphylococcus saprophyticus and in the given study, it was named B6. At 37 °C, pH 7.5 and 120 h of incubation, it removed 77% Cr(VI) from the reaction mixture. B6 was exposed to UV to obtain mutant. Exposure of 15 min to a UV lamp gave mutant MB6, which showed a removal capacity of 77% after 72 h only. Cr(VI) removal capacity of the mutant was then analyzed in the free and attached form where coal and sodium alginate were used as solid surfaces. Mutants immobilized on coal showed 91% Cr(VI) removal after 96 h, while sodium alginate showed 58% Cr(VI) removal in 120 h, thus showing coal as a more effective surface for adsorption.@*Conclusion, significance and impact of study@#Our present study shows the use of cheap and environmentally friendly methods to remediate tannery wastewater, which is a big problem in a country like Pakistan. Pakistan is the second largest producer of leather but lacks a wastewater treatment facility. So, this method offers in-situ wastewater treatment, which can be further enhanced in different ways.

Study on the biological exposure limit of whole blood chromium in occupational hexavalent chromium compounds exposed population / 中国职业医学

ObjectiveTo analyze the exposure-response relationship of peripheral whole blood chromium level and lung function as well as genetic toxicity indicators in workers exposed to hexavalent chromium [Cr(Ⅵ)] compounds, and to propose a biological exposure limit of whole blood chromium for soluble Cr(Ⅵ) compounds-exposed workers. Methods A total of 515 workers from a dynamic occupational Cr(Ⅵ) compounds-exposed cohort in an enterprise from 2010 to 2017 were selected as the research subjects using a retrospective cohort study. A total of 918 followed-up results of research subjects and baseline data of a cohort were analyzed based on bibliometric analysis. The results include lung function tests, whole blood chromium level detected by inductively coupled plasma-mass spectrometry, urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) detected by high performance liquid chromatography-tandem mass spectrometry, peripheral micronuclei frequency (MNF) detected by cytokinesis-block micronucleus assay, and mitochondrial DNA copy number (mtCN) detected by real-time fluorescence quantitative polymerase chain reaction. Results The results of bibliometric analysis showed that domestic and foreign studies on biological monitoring of Cr(Ⅵ) compounds increased year by year in the past 30 years, and whole blood chromium levels had a good correlation with the occupational Cr(Ⅵ) compounds exposure. The geometric mean of whole blood chromium levels in males and females among the occupational Cr(Ⅵ) compounds exposure cohort was 2.77 and 1.79 μg/L, respectively. A turning point appeared in 6.00 μg/L chromium in whole blood of the exposure-response curve of whole blood chromium levels with lung function indicators and genetic toxicity indicators. For each unit increase in the natural logarithm-transformed whole blood chromium level, the forced expiratory volume in one second (FEV1) decreased by 0.05 L, the FEV1/forced-vital-capacity decreased by 0.67%, the peak expiratory flow decreased by 0.15 L/s, the maximal mid-expiratory flow decreased by 0.09 L/s, the MNF increased by 0.149‰, the urinary 8-OHdG increased by 0.090 μg/g, and the mtCN increased by 0.013. When the whole blood chromium level was >6.00 μg/L, there was a significant increase in urinary 8-OHdG, MNF, and mtCN (all P<0.01). Conclusion The level of whole blood chromium can be used as a biomarker for occupational exposure to soluble Cr(Ⅵ) compounds. The preliminary biological exposure limit is set at 6.00 μg/L for whole blood chromium in workers exposed to soluble Cr(Ⅵ) compounds.

Effect of vitamin C on intestinal flora disorders in Cr(VI)-contaminated mice / 环境与职业医学

Background Hexavalent chromium [Cr(VI)] exposure can cause structural disruption of intestinal flora and functional impairment. Vitamin C (VC) is one of the essential micronutrients, which plays an important role in promoting the growth of intestinal probiotics, improving the intestinal barrier, and maintaining the homeostasis of intestinal flora. However, the regulatory effect of VC on the intestinal flora disorders caused by Cr(VI) exposure remains to be investigated. Objective To investigate the effect of VC on intestinal flora disruption in mice due to Cr(VI) exposure. Methods Thirty-two SPF-grade C57BL/6 mice were acclimatized and fed for 3 d and randomly divided into control (Con), VC, potassium dichromate [K2Cr2O7, Cr(VI)], and VC+K2Cr2O7 [VC+Cr(VI)] groups. At 8:00 a.m. on day 4, the Con group (double-distilled water given by gavage and injected intraperitoneally), the VC group (VC given by gavage and double-distilled water injected intraperitoneally), the Cr(VI) group (double-distilled water given by gavage and K2Cr2O7 solution injected intraperitoneally), and the VC+Cr(VI) group (VC given by gavage and K2Cr2O7 solution injected intraperitoneally) were treated. The dose of VC was 200 mg·kg−1, and the dose of K2Cr2O7 was 1.25 mg·kg−1. The mice were treated for 45 consecutive days and then executed, the contents of the colon were sampled in sterile freezing tubes, and three replicates were collected from each group. After labeling, the samples were immediately put into liquid nitrogen for rapid freezing. After all the samples were collected, they were transferred to a -80 ℃ ultra-low temperature refrigerator for storage. Samples of colon contents were analyzed for intestinal flora structure by high-throughput sequencing and bioinformatics software. Results The Cr(VI) exposure resulted in reduced body weight gain values in mice compared to the Con group. Pathological changes occurred in the ileal tissue of mice, with significant inflammatory cell infiltration in the Cr(VI) group and reduced inflammatory cell infiltration in the VC+Cr(VI) group. The number of operational taxonomic units (OTUs) of intestinal flora was altered in the Cr(VI) group of mice. In the α diversity analysis, the mean Sobs index in the Cr(VI) group was 240.333±67.796, the Chao index was 258.173±64.813, and the Ace index was 259.481±66.891, which were significantly lower than those in the Con group (P<0.05), the PD whole tree index in the Cr(VI) group was 27.863±2.399, which was significantly higher than that in the Con group (P<0.05), and the VC intervention significantly reversed the changes of the above indexes due to Cr(VI) exposure (P<0.05). In the β diversity analysis, the principal coordinates analysis (PCoA) results showed a significant separation between the Cr(VI) group and the Con group, and after the VC intervention, there was a retraction of the separation trend and the difference was reduced. The multi-sample similarity dendrogram results showed that the control and the VC groups clustered together first, then with the VC+Cr(VI) group, and finally with the Cr(VI) group. The abundances of Bacteroidetes, Saccharibacteria, and Tenericutes in the intestine of mice in the Cr(VI) group were decreased, and the abundance of Firmicutes was increased; the abundances of Lactobacillus, Alistipes, Bacteroides, and Ruminiclostridium were also increased. Included among these, Bacteroides showed a significantly higher abundance compared to the control mice (P<0.05). Changes in the abundances of phyla and genera of the above mentioned gut microorganisms were reversed after the VC intervention. Conclusion Cr(VI) exposure can lead to intestinal damage and disorganization of the intestinal flora structure in mice, while VC intervention can ameliorate the above changes to a certain extent and normalize the intestinal flora structure.

Effect of hexavalent chromium-induced ribosomal DNA copy number variation on DNA damage response in various cell lines / 预防医学

Objective@#To investigate the effect of ribosomal DNA (rDNA) copy number variation caused by hexavalent chromium exposure on DNA damage response in different cell lines, so as to provide insights into the involvement of hexavalent chromium-induced rDNA copy number variation in DNA damage responses. @*@#Methods Human lung epithelial BEAS-2B cells and human embryonic lung MRC-5 cells were treated with 2 μmol/L potassium dichromate for 24 hours, and then cells were transferred to fresh media for further incubation, while cells treated with the same volume of phosphate buffer solution served as controls. Cells treated with potassium dichromate for 24 hours, and 3 and 7 days post-detoxification, were harvested, and rDNA copy number was quantified in cells using a quantitative fluorescent real-time PCR assay. Cell cycle, apoptosis and DNA damage were detected using a Muse cell analyzer, and the DNA damage was evaluated with the proportion of ataxia telangiectasia-mutated (ATM) gene activation, proportion of double-strand DNA breaks and the percentage of the H2A.X variant histone phosphorylatio.@*@# Results The 45S and 5S rDNA copy numbers of were significantly higher in MRC-5 cells than in BEAS-2B cells [(1.54±0.26) vs. (1.02±0.18), P<0.05; (6.97±1.07) vs. (3.00±0.15), P<0.05]. The 45S rDNA copy number was lower in MRC-5 cells 3 days post-detoxification (0.80±0.04) than in controls (P<0.05), and was higher in BEAS-2B cells 3 days post-detoxification (1.43±0.07) than in controls (P<0.05) . G0/G1 phase arrest was found in MRC-5 cells 24 hours post-treatment, and the apoptotic rates were significantly higher in MRC-5 cells 3 and 7 days post-detoxification than in controls [(11.53±1.53)%, (18.33±0.70)% vs. (3.53±0.93)%, P<0.05]. The overall apoptotic rates 24 hours post-treatment and 3 days post-detoxification [(2.80±0.17)%, (3.33±0.57)% vs. (1.53±0.61)%, P<0.05], proportion of ATM gene activation 3 days post-detoxification [(3.37±0.67%) vs. (1.18±0.22)%, P<0.05], proportion of double-strand DNA breaks 3 days post-detoxification [(4.45±0.85)% vs. (0.97±0.21)%, P<0.05] and percentage of the H2A.X variant histone phosphorylation 3 days post-detoxification [(1.68±0.56)% vs. (0.29±0.06)%, P<0.05] in BEAS-2B cells were higher than in controls. @*Conclusions@#Hexavalent chromium-induced rDNA copy number variation affects DNA damage response in different cell lines. A stronger DNA damage response is found in BEAS-2B cells with a low rDNA copy number, and a relative stable response is observed in MRC-5 cells with a high rDNA copy number.

Evaluation of EDM inclusion into the conventional polishing of printed Co-Cr alloy by selective laser melting / Avaliação da inclusão de EDM no polimento convencional da liga de Co-Cr impressa por fusão seletiva a laser

Objective: The selective laser melting (SLM) technique used in manufacturing results in a rougher surface that requires more satisfying processing than conventional hand-finishing operations. The electro discharge machine (EDM) has various possibilities in the adjustment of surfaces. The present study assesses whether the participation of the EDM technique with the conventional finishing and polishing methods enables surface improvement for the Cobalt-Chromium alloy fabricated by SLM. Material and Methods: Twenty discs of cobalt chromium alloy were fabricated by SLM, divided equally into two groups: (TF) control group for finishing and polishing in the conventional method in accordance with the manufacturer's recommendations; and (EF) group for conducting polishing incorporating the EDM method. Results: The EF group recorded the lowest mean value of surface roughness and the highest mean value of micro hardness compared to the TF group. Furthermore, statistically significant differences (P < 0.05) were found for surface roughness as well as micro hardness. Conclusion: Reliance of the electric discharge machine proactively within finishing and polishing procedures promotes competence in the conventional polishing method and improves the surface properties of cobalt chromium alloy printed by SLM technology (AU)

Objetivo: A técnica de fusão a laser seletiva (SLM) usada na fabricação resulta em uma superfície mais rugosa a qual requer um processamento mais satisfatório do que o acabamento manual. A máquina de eletro descarga (EDM) possui várias possibilidades no ajuste de superfícies. O presente estudo avalia se a participação da técnica EDM associada aos métodos convencionais de acabamento e polimento possibilita a melhora da superfície da liga Cobalto-Cromo fabricada através da SLM. Material e Métodos: Vinte discos de liga de cromo-cobalto foram confeccionados por SLM, e divididos igualmente em dois grupos: (TF) grupo controle, realizado acabamento e polimento pelo método convencional de acordo com as recomendações do fabricante; e (EF) grupo do polimento associado ao método EDM. Resultados: O grupo EF registrou o menor valor médio de rugosidade superficial e o maior valor médio de microdureza em relação ao grupo TF. Além disso, diferenças estatisticamente significativas (P < 0,05) foram encontradas para rugosidade superficial, assim como para a microdureza. Conclusão: A confiança na máquina de descarga elétrica proativamente nos procedimentos de acabamento e polimento promove a competência no método de polimento convencional e melhora as propriedades de superfície da liga de cromo-cobalto impressa pela tecnologia SLM(AU)

Isolation and screening of chromium resistant bacteria from industrial waste for bioremediation purposes / Isolamento e triagem de bactérias resistentes ao cromo de resíduos industriais para fins de biorremediação

Abstract Chromium (VI) a highly toxic metal, a major constituent of industrial waste. It is continuously release in soil and water, causes environmental and health related issues, which is increasing public concern in developing countries like Pakistan. The basic aim of this study was isolation and screening of chromium resistant bacteria from industrial waste collected from Korangi and Lyari, Karachi (24˚52ʹ46.0ʺN 66˚59ʹ25.7ʺE and 24˚48ʹ37.5ʺN 67˚06ʹ52.6ʺE). Among total of 53 isolated strains, seven bacterial strains were selected through selective enrichment and identified on the basis of morphological and biochemical characteristics. These strains were designated as S11, S13, S17, S18, S30, S35 and S48, resistance was determined against varying concentrations of chromium (100-1500 mg/l). Two bacterial strains S35 and S48 showed maximum resistance to chromium (1600 mg/l). Bacterial strains S35 and S48 were identified through 16S rRNA sequence and showed 99% similarity to Bacillus paranthracis and Bacillus paramycoides. Furthermore, growth condition including temperature and pH were optimized for both bacterial strains, showed maximum growth at temperature 30ºC and at optimum pH 7.5 and 6.5 respectively. It is concluded that indigenous bacterial strains isolated from metal contaminated industrial effluent use their innate ability to transform toxic heavy metals to less or nontoxic form and can offer an effective tool for monitoring heavy metal contamination in the environment.

Resumo O cromo (VI), metal altamente tóxico, é um dos principais constituintes dos resíduos industriais. É liberado no solo e na água, causa problemas ambientais e de saúde de crescente preocupação pública em países em desenvolvimento como o Paquistão. O objetivo básico deste estudo foi o isolamento e a triagem de bactérias resistentes ao cromo de resíduos industriais coletados em Korangi e Lyari, Karachi (24˚52'46,0"N 66˚59'25,7"E e 24˚48'37,5"N 67˚06'52,6"E). Do total de 53 cepas isoladas, sete cepas bacterianas foram selecionadas por enriquecimento seletivo e identificadas com base em características morfológicas e bioquímicas. Essas cepas foram designadas como S11, S13, S17, S18, S30, S35 e S48, apresentaram alta resistência aos metais contra concentrações variáveis (100-1500 mg / l) de cromo. Já as cepas S35 e S48 foram identificadas por meio da sequência 16S rRNA e apresentaram 99% de similaridade com Bacillus paranthracis e Bacillus paramycoides. Além disso, as condições de crescimento incluindo temperatura e pH foram otimizadas e ambas as cepas bacterianas apresentaram crescimento máximo na temperatura de 30 ºC, enquanto seu pH ótimo foi observado em 7,5 e 6,5, respectivamente. Conclui-se que o potencial de resistência dessas bactérias resistentes ao cromo pode ser efetivamente utilizado na remoção de cromo de efluentes industriais contaminados. Técnicas de base biológica usando bactérias ajudarão a fornecer métodos mais baratos e ecológicos de remoção, recuperação e desintoxicação de cromo.

Chromium supplemented carbohydrate diets for Cirrhinus mrigala: effects on body composition, gut enzyme activity and hematological parameters / Dietas com carboidratos suplementados com cromo para Cirrhinus mrigala: efeitos sobre a composição corporal, atividade enzimática intestinal e parâmetros hematológicos

A ninety days nutritional trial was directed to explore the effects of dietary chromium on body composition, gut enzyme activity and physiological status of Cirrhinus mrigala by using G & NG corn. Six experimental diets were prepared by using different levels of chromium chloride hexahydrate (0, 0.2, 0.4 mg/kg, each with G & NG corn). For this experimental trial, 480 fingerlings, irrespective of sex were distributed in six aquariums each with replicate. Results revealed that gelatinized corn along with increasing level of Cr2Cl3.6H2O have a positive impact upon body composition of fish. Hematology was positively correlated with chromium chloride hexahydrate supplementation in gelatinized corn. Amylase gut enzyme also showed significant (P<0.05) increase in group fed with chromium chloride hexahydrate supplemented diet (G corn). However, corn with chromium chloride hexahydrate supplementation did not revealed any significant impact on gut protease enzyme activity. From these results it can be concluded that both chromium chloride hexahydrate and gelatinized corn in fish feed are very beneficial to improve body composition, enzymes activity and physiological health status of fish.

Um ensaio nutricional de 90 dias foi dirigido para explorar os efeitos do cromo dietético na composição corporal, atividade enzimática intestinal e estado fisiológico de Cirrhinus mrigala usando milho G & NG. Seis dietas experimentais foram preparadas usando diferentes níveis de cloreto de cromo hexa-hidratado (0, 0,2, 0,4 mg/kg, cada um com milho G e NG). Para este ensaio experimental, 480 alevinos, independentemente do sexo, foram distribuídos em seis aquários, cada um com réplicas. Os resultados revelaram que o milho gelatinizado, juntamente com o aumento do nível de Cr2Cl3.6H2O, tem um impacto positivo na composição corporal dos peixes. A hematologia foi positivamente correlacionada com a suplementação de cloreto de cromo hexa-hidratado em milho gelatinizado. A enzima amilase intestinal também apresentou aumento significativo (P <0,05) no grupo alimentado com dieta suplementada com cloreto de cromo hexa-hidratado (milho G). No entanto, o milho com suplementação de hexahidrato de cloreto de cromo não revelou nenhum impacto significativo na atividade da enzima protease intestinal. Desses resultados, pode-se concluir que tanto o cloreto de cromo hexa-hidratado quanto o milho gelatinizado na alimentação de peixes são muito benéficos para melhorar a composição corporal, a atividade de enzimas e o estado fisiológico de saúde dos peixes.

Isolation and screening of chromium resistant bacteria from industrial waste for bioremediation purposes / Isolamento e triagem de bactérias resistentes ao cromo de resíduos industriais para fins de biorremediação

Chromium (VI) a highly toxic metal, a major constituent of industrial waste. It is continuously release in soil and water, causes environmental and health related issues, which is increasing public concern in developing countries like Pakistan. The basic aim of this study was isolation and screening of chromium resistant bacteria from industrial waste collected from Korangi and Lyari, Karachi (24˚52ʹ46.0ʺN 66˚59ʹ25.7ʺE and 24˚48ʹ37.5ʺN 67˚06ʹ52.6ʺE). Among total of 53 isolated strains, seven bacterial strains were selected through selective enrichment and identified on the basis of morphological and biochemical characteristics. These strains were designated as S11, S13, S17, S18, S30, S35 and S48, resistance was determined against varying concentrations of chromium (100-1500 mg/l). Two bacterial strains S35 and S48 showed maximum resistance to chromium (1600 mg/l). Bacterial strains S35 and S48 were identified through 16S rRNA sequence and showed 99% similarity to Bacillus paranthracis and Bacillus paramycoides. Furthermore, growth condition including temperature and pH were optimized for both bacterial strains, showed maximum growth at temperature 30ºC and at optimum pH 7.5 and 6.5 respectively. It is concluded that indigenous bacterial strains isolated from metal contaminated industrial effluent use their innate ability to transform toxic heavy metals to less or nontoxic form and can offer an effective tool for monitoring heavy metal contamination in the environment.

O cromo (VI), metal altamente tóxico, é um dos principais constituintes dos resíduos industriais. É liberado no solo e na água, causa problemas ambientais e de saúde de crescente preocupação pública em países em desenvolvimento como o Paquistão. O objetivo básico deste estudo foi o isolamento e a triagem de bactérias resistentes ao cromo de resíduos industriais coletados em Korangi e Lyari, Karachi (24˚52’46,0”N 66˚59’25,7”E e 24˚48’37,5”N 67˚06’52,6”E). Do total de 53 cepas isoladas, sete cepas bacterianas foram selecionadas por enriquecimento seletivo e identificadas com base em características morfológicas e bioquímicas. Essas cepas foram designadas como S11, S13, S17, S18, S30, S35 e S48, apresentaram alta resistência aos metais contra concentrações variáveis (100-1500 mg / l) de cromo. Já as cepas S35 e S48 foram identificadas por meio da sequência 16S rRNA e apresentaram 99% de similaridade com Bacillus paranthracis e Bacillus paramycoides. Além disso, as condições de crescimento incluindo temperatura e pH foram otimizadas e ambas as cepas bacterianas apresentaram crescimento máximo na temperatura de 30ºC, enquanto seu pH ótimo foi observado em 7,5 e 6,5, respectivamente. Conclui-se que o potencial de resistência dessas bactérias resistentes ao cromo pode ser efetivamente utilizado na remoção de cromo de efluentes industriais contaminados. Técnicas de base biológica usando bactérias ajudarão a fornecer métodos mais baratos e ecológicos de remoção, recuperação e desintoxicação de cromo.

Chromium supplemented carbohydrate diets for Cirrhinus mrigala: effects on body composition, gut enzyme activity and hematological parameters

Abstract A ninety days nutritional trial was directed to explore the effects of dietary chromium on body composition, gut enzyme activity and physiological status of Cirrhinus mrigala by using G & NG corn. Six experimental diets were prepared by using different levels of chromium chloride hexahydrate (0, 0.2, 0.4 mg/kg, each with G & NG corn). For this experimental trial, 480 fingerlings, irrespective of sex were distributed in six aquariums each with replicate. Results revealed that gelatinized corn along with increasing level of Cr2Cl3.6H2O have a positive impact upon body composition of fish. Hematology was positively correlated with chromium chloride hexahydrate supplementation in gelatinized corn. Amylase gut enzyme also showed significant (P 0.05) increase in group fed with chromium chloride hexahydrate supplemented diet (G corn). However, corn with chromium chloride hexahydrate supplementation did not revealed any significant impact on gut protease enzyme activity. From these results it can be concluded that both chromium chloride hexahydrate and gelatinized corn in fish feed are very beneficial to improve body composition, enzymes activity and physiological health status of fish.

Resumo Um ensaio nutricional de 90 dias foi dirigido para explorar os efeitos do cromo dietético na composição corporal, atividade enzimática intestinal e estado fisiológico de Cirrhinus mrigala usando milho G & NG. Seis dietas experimentais foram preparadas usando diferentes níveis de cloreto de cromo hexa-hidratado (0, 0,2, 0,4 mg/kg, cada um com milho G e NG). Para este ensaio experimental, 480 alevinos, independentemente do sexo, foram distribuídos em seis aquários, cada um com réplicas. Os resultados revelaram que o milho gelatinizado, juntamente com o aumento do nível de Cr2Cl3.6H2O, tem um impacto positivo na composição corporal dos peixes. A hematologia foi positivamente correlacionada com a suplementação de cloreto de cromo hexa-hidratado em milho gelatinizado. A enzima amilase intestinal também apresentou aumento significativo (P 0,05) no grupo alimentado com dieta suplementada com cloreto de cromo hexa-hidratado (milho G). No entanto, o milho com suplementação de hexahidrato de cloreto de cromo não revelou nenhum impacto significativo na atividade da enzima protease intestinal. Desses resultados, pode-se concluir que tanto o cloreto de cromo hexa-hidratado quanto o milho gelatinizado na alimentação de peixes são muito benéficos para melhorar a composição corporal, a atividade de enzimas e o estado fisiológico de saúde dos peixes.

Isolation and screening of chromium resistant bacteria from industrial waste for bioremediation purposes

Abstract Chromium (VI) a highly toxic metal, a major constituent of industrial waste. It is continuously release in soil and water, causes environmental and health related issues, which is increasing public concern in developing countries like Pakistan. The basic aim of this study was isolation and screening of chromium resistant bacteria from industrial waste collected from Korangi and Lyari, Karachi (245246.0N 665925.7E and 244837.5N 670652.6E). Among total of 53 isolated strains, seven bacterial strains were selected through selective enrichment and identified on the basis of morphological and biochemical characteristics. These strains were designated as S11, S13, S17, S18, S30, S35 and S48, resistance was determined against varying concentrations of chromium (100-1500 mg/l). Two bacterial strains S35 and S48 showed maximum resistance to chromium (1600 mg/l). Bacterial strains S35 and S48 were identified through 16S rRNA sequence and showed 99% similarity to Bacillus paranthracis and Bacillus paramycoides. Furthermore, growth condition including temperature and pH were optimized for both bacterial strains, showed maximum growth at temperature 30ºC and at optimum pH 7.5 and 6.5 respectively. It is concluded that indigenous bacterial strains isolated from metal contaminated industrial effluent use their innate ability to transform toxic heavy metals to less or nontoxic form and can offer an effective tool for monitoring heavy metal contamination in the environment.

Resumo O cromo (VI), metal altamente tóxico, é um dos principais constituintes dos resíduos industriais. É liberado no solo e na água, causa problemas ambientais e de saúde de crescente preocupação pública em países em desenvolvimento como o Paquistão. O objetivo básico deste estudo foi o isolamento e a triagem de bactérias resistentes ao cromo de resíduos industriais coletados em Korangi e Lyari, Karachi (245246,0N 665925,7E e 244837,5N 670652,6E). Do total de 53 cepas isoladas, sete cepas bacterianas foram selecionadas por enriquecimento seletivo e identificadas com base em características morfológicas e bioquímicas. Essas cepas foram designadas como S11, S13, S17, S18, S30, S35 e S48, apresentaram alta resistência aos metais contra concentrações variáveis (100-1500 mg / l) de cromo. Já as cepas S35 e S48 foram identificadas por meio da sequência 16S rRNA e apresentaram 99% de similaridade com Bacillus paranthracis e Bacillus paramycoides. Além disso, as condições de crescimento incluindo temperatura e pH foram otimizadas e ambas as cepas bacterianas apresentaram crescimento máximo na temperatura de 30 ºC, enquanto seu pH ótimo foi observado em 7,5 e 6,5, respectivamente. Conclui-se que o potencial de resistência dessas bactérias resistentes ao cromo pode ser efetivamente utilizado na remoção de cromo de efluentes industriais contaminados. Técnicas de base biológica usando bactérias ajudarão a fornecer métodos mais baratos e ecológicos de remoção, recuperação e desintoxicação de cromo.

Resistencia estructural de prótesis dentales acrílicas y de cromo cobalto en cadáveres quemados o carbonizados: a propósito de dos casos / Structural resistance of acrylic and cobalt-chromium dental prostheses in burned or charred corpses: a propos of two cases

La identificación humana genera continuos desafíos técnicos y científicos para los equipos de expertos forenses en sus múltiples contextos de intervención. Uno de los más complejos, está representado por el hallazgo de cadáveres quemados o carbonizados, donde las huellas dactilares resultan inviables. En tales situaciones, los tejidos de la cavidad oral han demostrado elevada tolerancia a la injuria térmica, aportando información decisiva, muchas veces com-plementada por estructuras protésicas recupera-das del occiso. El presente artículo reporta dos ca-sos donde las prótesis dentales acrílicas y de cromo cobalto exhibieron notable indemnidad pese a la gran pérdida orgánica sufrida por los cuerpos de las víc-timas ante la acción vulnerante del fuego, otorgando valor probatorio para contribuir en el establecimien-to de su identidad (AU)

Human identification generates continuous technical and scientific challenges for teams of forensic experts in their multiple contexts of intervention. One of the most complex is represented by the discovery of burned or charred corpses, where fingerprints are unviable. In such situations, the tissues of the oral cavity have shown high tolerance to thermal injury, providing decisive information, often complemented by prosthetic structures recovered from the deceased. This article reports two cases where the acrylic and cobalt chrome dental prostheses presented notable indemnity despite the great organic loss suffered by the bodies of the victims before the damaging action of fire, granting probative value to contribute to the establishment of their identity (AU)

A Comparative Study of Chromium: Therapeutic Uses and Toxicological Effects on Human Health

Chromium is an essential trace element whose deficiency can cause impairment of glucose tolerance, growth and various biological functions. There are two isotopes of chromium-trivalent chromium and hexavalent chromium. Both the isotopes of chromium have quite different effects on the human body. The objective of this narrative review is to compile the different effects of the two isotopes of chromium and give a comprehensive analysis of the effects of hexavalent and trivalent chromium. Data from various studies across different forums were compared to provide a concrete analysis of the therapeutic and harmful effects of two isotopes of chromium on human health. Chromium plays a vital role in the biological functions of the body. It might be helpful in balancing the glycaemic levels, triglyceride levels and cholesterol levels in the body. Excessive intake of chromium is harmful for health. Overexposure to chromium can lead to carcinogenic effects. Consumption of an insufficient amount of chromium might not be adequate as well. Trivalent chromium can be quite beneficial if taken in proper quantities. Hexavalent chromium can cause cancer. Trivalent chromium is beneficial, while hexavalent chromium is harmful to human health.

Thermal expansion and corrosion resistance of cobalt-chromium alloys fabricated by contemporary manufacturing processes: an in vitro study / Expansión térmica y resistencia a la corrosión de aleaciones de cobalto-cromo fabricadas mediante procesos de abricación contemporáneos: un estudio in vitro

In Purpose: The fabrication technique can influence the mechanical properties of Cobalt-Chromium (Co-Cr) dental alloys. Hence, the present study aims to determine the corrosion resistance and thermal expansion of alloys manufactured using three contemporary techniques. Material and Methods: A total of nine specimens of Co-Cr alloy were prepared according to ISO 22674 by each one of the three manufacturing processes (three in each process); conventional casting, direct metal laser sintering (DMLS) and milling (MIL). All these specimens were tested for coefficient of thermal expansion and corrosion resistance. The data was tabulated and analyzed statistically. Results: The difference in the thermal expansion of alloys fabricated using three techniques was non-significant at almost all the temperatures from 50 ºC to 950 ºC (p>0.05), except 450 ºC and 600 °C. The polarization resistance of specimens manufactured using the conventional method was more compared to DMLS and MIL at pH 5 (Conventional>MIL>DMLS) (p<0.001). Conclusion: The thermal expansion behavior of alloys manufactured using the three selected techniques were similar, whereas, at acidic pH, the corrosion resistance of conventional and MIL were better than the DMLS.

Antecedentes: La técnica de fabricación puede influir en las propiedades mecánicas de las aleaciones dentales de cobalto-cromo (Co-Cr). Por lo tanto, el presente estudio tiene como objetivo determinar la resistencia a la corrosión y la expansión térmica de aleaciones fabricadas con tres técnicas contemporáneas. Material y Métodos: Se prepararon un total de nueve probetas de aleación de Co-Cr según ISO 22674 por cada uno de los tres procesos de fabricación (tres en cada proceso); fundición convencional, sinterización directa de metal por láser (DMLS) y fresado (MIL). Todos estos especímenes fueron probados para determinar el coeficiente de expansión térmica y la resistencia a la corrosión. Los datos fueron tabulados y analizados estadísticamente. Resultados: La diferencia en la dilatación térmica de las aleaciones fabricadas con las tres técnicas no fue significativa en casi todas las temperaturas desde 50ºC hasta 950ºC (p>0,05), excepto 450ºC y 600ºC. La resistencia a la polarización de las muestras fabricadas con el método convencional fue mayor en comparación con DMLS y MIL a pH 5 (Convencional>MIL>DMLS) (p<0, 0 01). Conclusión: El comportamiento de expansión térmica de las aleaciones fabricadas con las tres técnicas seleccionadas fue similar, mientras que, a pH ácido, la resistencia a la corrosión de la convencional y la MIL fue mejor que la de la DMLS.

Interaction of Carthamus oil, chromium picolinate and glyburide in blood glucose and its impact on liver enzymes and lipid profile in diabetes-induced rats

SUMMARY Introduction: Carthamus oil is a compound that has the potential to be used in numerous applications due to its anti-inflammatory, antioxidant, immunomodulatory and neuroprotective effects. Chromium picolinate has been indicated for the control of insulin resistance. Aim: To evaluate the effect of Carthamus oil (30 mg/kg) and chromium picolinate (5 µg/kg) interaction with oral glyburide in chemically diabetes-induced Wistar rats and its influence on drug therapy. Method: Diabetes mellitus was induced with streptozotocin, and the animals were randomized into experimental groups (n= 6/group), who received gastric gavage treatments for ten days, G1: control, G2: diabetic and received glyburide, G3: diabetic and received the interaction of Carthamus oil and chromium picolinate, G4: diabetic and received the interaction ofglyburide, Carthamus oil and chromium picolinate. After the treatment period, fasting blood glucose, post-sucrose blood glucose, total cholesterol and triglyceride levels, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in blood serum were compared, in addition to urine analysis. Results: In this study, the only altered parameters were the post-sucrose blood glucose measurement with the lowest result for G4 (P <0.05) and the ALT measurement, with lower values for G4 (P <0.05) compared to G1. Conclusion: It can be concluded that the unprecedented interaction of Carthamus oil, chromium picolinate and glyburide contributed to the reduction of blood glucose and serum levels of ALT in diabetic rats and is promising for future studies in humans.

Introdução: o óleo de cártamo (Carthamus oil) tem sido utilizado em diversas aplicações devido suas ações antiinflamatória, antioxidante, imunomoduladora e neuro protetora. O picolinato de cromo tem sido indicado para o controle da resistência à insulina. Objetivo: avaliar o efeito da interação de óleo de cártamo (30 mg/kg) e picolinato de cromo (5 µg/kg) com glibenclamida em ratos com diabetes induzida. Metodologia: a indução de diabetes mellitus foi realizada com injeção intra-peritoneal de estreptozotocina e os animais foram aleatoriamente distribuidos em grupos experimentais (n= 6/grupo), que receberam os tratamentos por gavagem gástrica durante dez dias, G1: controle, G2: grupo diabético que recebeu gliben-clamida, G3: grupo diabético que recebeu óleo de cártamo e picolinato de cromo, G4: grupo diabético que recebeu glibenclamida, óleo de cártamo e picolinato de cromo. Após os dias de tratamento via oral, determinou-se o peso corpóreo, glicemia de jejum, colesterol total, triglicerideos, glicemia após uma hora de gavagem gástrica com sacarose, transaminases hepáticas e a avaliação da urina. Resultados: a análise estatistica dos dados indicou que os únicos parâmetros alterados foram a glicemia após a ingestão de sacarose, os menores valores obtidos foram em G4 (P <0.05) e a redução dos niveis séricos de ALT em G4 (P <0.05) quando comparados com G1. Conclusão: a interação inédita do óleo de cártamo, picolinato de cromo e glibencla-mida contribuiu para a redução da glicose sanguinea e dos niveis séricos de ALT em ratos diabéticos, é promissora para estudos futuros em humanos.

Introducción: el aceite de cártamo (Carthamus oil) se ha utilizado en diversas aplicaciones debido a sus propiedades antiinflamatorias, antioxidantes, inmunomodu-ladoras y neuroprotectoras. El picolinato de cromo ha sido indicado para el control de la resistencia a la insulina. Objetivo: evaluar el efecto de la interacción de aceite de cártamo (30 mg/kg) y picolinato de cromo (5 µg/kg) con glibenclamida en ratas con diabetes inducida. Metodología: la inducción de diabetes mellitus se realizó con inyección intraperitoneal de estreptozotocina y los animales se distribuyeron aleatoriamente en grupos experimentales (n= 6/grupo), los cuales recibieron tratamientos por sonda gástrica durante diez dias, G1: control, G2: grupo diabético que recibieron glibenclamida, G3: grupo diabético que recibió aceite de cártamo y picolinato de cromo, G4: grupo diabético que recibió glibenclamida, aceite de cártamo y picolinato de cromo. Después de los dias de tratamiento oral, se determinó peso corporal, glucosa en ayunas, colesterol total, triglicéridos, glucosa después de una hora de sonda gástrica con sacarosa, transaminasas hepáticas y evaluación de orina. Resultados: el análisis estadistico de los datos indicó que los únicos parámetros alterados fueron la glucosa en sangre después de la ingesta de sacarosa, los valores más bajos obtenidos fueron en G4 (P <0,05) y la reducción de los niveles séricos de ALT en G4 (P <0,05) cuando en comparación con G1. Conclusión: la interacción sin precedentes del aceite de cártamo, el picolinato de cromo y la glibenclamida contribuyó a la reducción de los niveles de glucosa en sangre y ALT sérica en ratas diabéticas, es prometedora para futuros estudios en humanos.

A Real-Time Investigation on Public Health Consequences of Chromium Laden Effluent from the Leather Industries

Background: Extensive evidence of elevated chromium (Cr) in the surface and groundwater exists. However, the importance of exposure toward Cr?associated health risks in areas with tanneries is still often neglected. These situations prompted an independent research study to investigate the views of those close?knit communities who are being directly affected by this tannery village. Objectives: To establish an understanding of the local demographics and; exploratory data analysis (EDA) to discover patterns in the occurrence of diseases; measure the awareness of residents of the presence of Cr and its harmful health effects. Methods: The EDA technique was used to conduct survey studies on data to uncover patterns, identify anomalies, test hypotheses, and validate assumptions using summary statistics and graphical representations. Results: Out of 14 diseases directly linked to high Cr toxicity, the study reported high levels of diarrhea, epigastric pain, and moderate?to?severe cases of vertigo among those aged more than 22 years. With over 90 active tanneries and toxic Cr released to the environment in a town of <78 km2 area (1.2 tannery/km), there are only 15 hospitals (0.2 hospitals/km) for the population currently accommodating more than a quarter?million people daily (3205 people/km). Conclusion: New mitigation strategies must be put forth to alleviate the negative impacts of the tanneries on the residents and nature most affected as well as the population as a whole.

Comparison of occupational exposure limits of hexavalent chromium compounds in China and foreign workplaces / 中国职业医学

@#Objective To compare and analyze the occupational exposure limit（OEL）of hexavalent chromium compounds in China and foreign countries. Methods The OEL and background information of hexavalent chromium compounds released by nine official and unofficial organizations in seven countries/regions were collected and sorted. The classification，limit levels， formulation principles and compound characteristics labeling of OEL were compared. Results The OEL values published by nine organizations ranged from 0.000 02 to 0.050 00 mg/m3 . Among them，the limits of seven organizations（including China） did not clearly distinguish the soluble types of hexavalent chromium compounds；the limits of eight organizations（including China）were calculated in terms of chromium；seven organizations（including China）have only developed OEL for long-term exposure. The OEL of hexavalent chromium in China was 0.050 00 mg/m3 which is relatively loose. Its carcinogenicity label was consistent with international standards，its sensitization label was consistent with some countries，and its percutaneous absorption label had not been included in the characteristic labeling of limit values. Conclusion It is suggested that the OEL of hexavalent chromium in China should be revised timely，and the systemic adverse effects caused by percutaneous absorption of hexavalent chromium compounds should be focused on. At the same time，it is recommended to systematically adjust the management concepts and principles of all carcinogens.

Effects of arsenic, selenium, lead and chromium in urine on blood pressure in people from arsenic exposure areas of Togtoh County, Inner Mongolia Autonomous Region / 中华地方病学杂志

Objective:To learn about the incidence of hypertension in residents of arsenic exposure areas of Togtoh County, Inner Mongolia Autonomous Region, and to analyze the influencing factors of hypertension.Methods:In Inner Mongolia Autonomous Region, Ciweigou of Togtoh County, a drinking water-type endemic arsenic poisoning area, and Lanjiayao of Horinger County, a non-arsenic poisoning area with similar living habits and economic conditions, permanent residents who had lived for ≥10 years were selected as the survey subjects. Totally 116 residents of Ciweigou (exposure group) and 68 residents of Lanjiayao (control group) were included in the survey. Blood pressure was measured and the contents of arsenic, selenium, lead and chromium in urine were detected, multivariate logistic regression was used to analyze the influencing factors of hypertension.Results:The detection rates of hypertension in exposure group and control group were 53.45% (62/116) and 70.59% (48/68), respectively, and the difference between the two groups was statistically significant (χ 2 = 5.33, P = 0.022). The contents of arsenic, selenium and chromium in urine of exposure group were higher than those of control group, and the content of lead in urine was lower than that of control group, and the differences were statistically significant ( Z = 13.04, 6.34, 11.28, - 9.91, P < 0.001). The results of multivariate logistic regression analysis showed that female, age ≥60 years old and high urinary arsenic content were the influencing factors of hypertension [odds ratio ( OR) = 2.074, 2.004, 0.424, 95% confidence interval ( CI): 1.113 - 3.866, 1.035 - 3.879, 0.219 - 0.820] in arsenic exposure areas. Conclusion:Female, age ≥60 years old and high urinary arsenic content are the influencing factors of hypertension in arsenic exposure areas of Togtoh County, Inner Mongolia Autonomous Region.

Effect of chromium-methionine supplementation on meat quality of broilers reared under heat stress / [Efeito da suplementação de cromo-metionina na qualidade da carne de frangos de corte criados em estresse por calor]

Objetivou-se avaliar o efeito da suplementação de cromo-metionina em dietas para frangos de corte criados em estresse por calor, no período de 22 a 43 dias de idade, nos parâmetros de qualidade da carne. Foram utilizados 336 frangos de corte, machos, da linhagem Cobb 500, com 21 dias de idade, distribuídos em delineamento em blocos inteiramente ao acaso, com quatro blocos (cada câmara climática), seis tratamentos (0; 0,10; 0,20; 0,40; 0,80 e 1,20mgkg-1 de Cr na forma de Cr-metionina), oito repetições e sete aves por unidade experimental. Aos 43 dias de idade, duas aves por unidade experimental foram selecionadas e abatidas para avaliação da qualidade da carne de peito, por meio dos parâmetros de pH15min, pH24h, luminosidade (L*), teor de vermelho (a*), teor de amarelo (b*), croma (C*), ângulo hue (Hº), capacidade de retenção de água, perda de peso por cozimento e força de cisalhamento. Houve efeito quadrático (P=0,0070) na capacidade de retenção de água da carne de peito. A suplementação de CrMet não afetou (P>0,05) os demais parâmetros de qualidade da carne. Assim, recomenda-se a suplementação de 0,59mgkg-1 de CrMet para frangos de corte para melhoria da capacidade de retenção de água do peito.(AU)

Hexavalent chromium-reducing bacteria on biosolids from the San Fernando Wastewater Treatment Plant in Medellín (Colombia) / Bacterias aisladas de biosólidos de la PTAR San Fernando en Medellín-Colombia con capacidad para reducir cromo hexavalente

ABSTRACT During the most recent decades, advances have been made to reduce the environmental impact by anthropogenic activities that constantly release toxic components into the environment, generating instability and damage to the health of biological communities. Among the different pollutants, heavy metals are important by virtue of their properties, which hinder their degradation or transformation into other less toxic compounds. Chromium is one of the metals of greatest global interest due to its use in multiple industries. Conventional methods using chromed materials in their processes, not only throw considerable amounts of waste into the environment, but also give little account of the fraction of hexavalent chromium (Cr6+) present in certain ecosystems. Bioremediation has been proposed as an economically viable and environmentally sustainable alternative. This work aimed to evaluate the chromium reduction capacity by bacteria isolated from a biosolids matrix obtained at the San Fernando Wastewater Treatment Plant (WWTP), located in Medellín (Colombia). Biosolids samples were grown in a nutrient agar enriched with different concentrations of Cr6+. The strains presenting the greater tolerance to chromium were isolated to perform reduction tests by triplicate, monitoring the concentration of the metal over time. Seven different bacterial species were obtained, among which Staphylococcus saprophyticus, Ochrobactrum anthropic, and Bacillus cereus showed the greatest ability to reduce Cr6+ (29.0%, 61.1 and 100%, at 96 h) respectively.

RESUMEN En las últimas décadas se ha trabajado activamente para reducir el impacto ambiental generado por las actividades antrópicas que constantemente liberan componentes tóxicos al ambiente generando inestabilidad y daños en la salud de las comunidades biológicas. Entre los diferentes contaminantes, los metales pesados revisten importancia en virtud de sus propiedades, que dificultan su degradación o transformación en otros compuestos menos tóxicos. El cromo es uno de los metales de mayor interés a nivel global por su uso en múltiples industrias. Los métodos convencionales que utilizan materiales cromados en sus procesos, no sólo arrojan cantidades considerables de residuos al ambiente, sino que dan poca cuenta de la fracción de Cr6+ presente en determinados ecosistemas. La biorremediación se ha propuesto como una alternativa económicamente viable y ambientalmente sostenible. El propósito del presente trabajo fue evaluar la capacidad de reducción de cromo por bacterias, aisladas de una matriz de biosólidos de la Planta de tratamiento de aguas residuales (PTAR) San Fernando en la ciudad de Medellín-Colombia. Muestras de biosólidos se cultivaron en Agar Nutritivo enriquecido con diferentes concentraciones de Cr6+. Las cepas que presentaron mayor tolerancia al cromo fueron aisladas para realizar ensayos de reducción por triplicado, monitoreando la concentración del metal en el tiempo. Se obtuvieron siete especies bacterianas diferentes dentro de las cuales se destacaron Staphylococcus saprophyticus, Ochrobactrum anthropi y Bacillus cereus por la capacidad de reducir Cr6+ a 96 h con eficiencias de 29.0%, 61.1% y 100%, respectivamente.