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The problem of increasing plastic pollution has emerged as a significant societal issue. Plastics can originate from various sources, and there is growing concern among researchers to study and investigate this new category of pollution. The plastic waste is found at the macro, micro, and nanoscale, and its study has had great significance according to the perspective of posing hazardous impacts on living organisms. Given the high demand for functional textiles, the textile industries are supporting the coating of different polymeric based finishes on the surface of textile products. The plastic debris emitted from these coated finishes are in the ranges of nanometric scale, so-called polymeric nanoplastics (PNPs). With the new terminology, polymeric nanoplastics (PNPs) released from textile finishes or coatings are being increasingly mentioned, and the term fibrous microplastics (FMPs) can be seen as outdated. This study is based on an intensive review of a very novel category of debris plastics (PNPs) mostly produced from textile finishes or coatings. In fact, FMPs and PNPs released from synthetic textiles and textiles coated with plastic-based finishes during washing activities are considered to be a major cause that contributes to the current overall load of microplastics (MPs) in the environment. A link between the concentration of NPs from textile fibers and NPs from textile polymeric-based coatings in freshwater and sediments within a particular local setting and the extent of activities of the textile industry has been demonstrated. Invested efforts have been paid to consider and concentrate on plastic pollution (nanoplastics from textile polymeric coatings). We also summarize existing methodologies to elucidate the identification and proactive quantification of nanoplastics shed from the textile polymeric coatings. To this end, more than 40 studies have been done to identify the physical, chemical, and mechanical parameters and to characterize nanoplastics.
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The inherent disadvantages of traditional nonflexible aerogels, such as high fragility and moisture sensitivity, severely restrict their applications. To address these issues, different techniques have been used to incorporate the flexibility in aerogel materials; hence, the term "flexible aerogels" was introduced. In the case of introducing flexibility, the organic part is induced with the inorganic part (flexible hybrid aerogels). Additionally, some more modern research is also available in the fabrication of hybrid flexible aerogels (based on organic-organic), the combination of two organic polymers. Moreover, a new type (single-component flexible aerogels) are quite a new category composed of only single materials; this category is very limited, charming to make the flexible aerogels pure from single polymers. The present review is composed of modern techniques and studies available to fabricate hybrid and single-component flexible aerogels. Their synthesis, factors affecting their parameters, and limitations associated with them are explained deeply. Moreover, a comparative analysis of drying methods and their effectiveness in the development of structures are described in detail. The further sections explain their properties and characterization methods. Eventually, their applications in a variety of multifunctional fields are covered. This article will support to introduce the roadmap pointing to a future direction in the production of the single-component flexible aerogel materials and their applications.
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OBJECTIVES: Wax typodonts are widely used as pre-clinical teaching tools to test and research the complex force systems created by archwire activations, however, a limitation is the inability to quantify the resultant statically indeterminate tooth movements. The aim of this study was to develop an analogue-to-digital typodont system to quantify the effects of archwire activations on individual typodont teeth in three dimensions. METHODS: The typodont system was developed using CAD/CAM technology. Posterior expansion, squared, tapered, asymmetrical arch forms and reversed curve of Spee activations were tested with three repeats. The resulting three-dimensional movements of individual typodont teeth were assessed with six degrees of freedom (df). Cartesian coordinate systems were set for each tooth. Mesio-distal, bucco-lingual and intrusive-extrusive movements were assessed as changes in the location of the geometrically estimated centre of resistance in the x, y and z axes, respectively. Torque, tip and rotation movements were assessed as the rotations around the mesio-distal, bucco-lingual and intrusive-extrusive axes, respectively. RESULTS: Individual typodont tooth displacements from each activation could reliably be described with six df. The transversal-to-sagittal movement ratio ranged from 2:1 to 7:1, depending on the activation. Asymmetrical arch form activations caused a midline shift and affected the lateral overjet. Reversing the curve of Spee led to intrusion of incisors and second molars, extrusion of premolars and first molars and pronounced first and third order effects. CONCLUSION: The digital typodont system is a promising teaching tool. The tested activations have implications in three dimensions, which should be considered when planning tooth movements.
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Má Oclusão , Humanos , Dente Molar , Dente Pré-Molar , Incisivo , Técnicas de Movimentação Dentária/métodosRESUMO
Acute gastroenteritis (AGE) is one of the most common diseases in children, and it continues to be a significant cause of morbidity and mortality worldwide. Norovirus is one of the major enteropathogens associated with both sporadic diarrhea and outbreaks of gastroenteritis. This study aims to investigate genotype diversity and molecular epidemiology of norovirus in Bangladesh. A total of 466 fecal specimens were collected from January 2014 to January 2019 from children below 5 years old with AGE in Bangladesh. All samples were analyzed by reverse transcriptase polymerase chain reaction to detect norovirus, and sequence analysis was conducted if found positive. Norovirus was detected in 5.1% (24 of 466) fecal specimens. Norovirus genotype GII.7 was predominant (62.5%, 15 of 24), followed by GII.3 (37.5%, 9 of 24). Coinfection between rotavirus and norovirus was found in 7 of 24 positive cases. Diarrhea (93.7%) and dehydration (89%) were the most common symptoms in children with AGE. About 80% of the positive cases were detected in children aged under 24 months. One seasonal peak (87.5% infection) was detected in the winter. This study suggests that norovirus continues to be one of the major etiologies of children AGE in Bangladesh. This study will provide a guideline to assess the burden of norovirus infection in Bangladesh, which will assist to combat against AGE.
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Infecções por Caliciviridae/epidemiologia , Fezes/virologia , Gastroenterite/epidemiologia , Variação Genética , Genótipo , Norovirus/genética , Bangladesh/epidemiologia , Infecções por Caliciviridae/virologia , Pré-Escolar , Feminino , Gastroenterite/virologia , Humanos , Lactente , Masculino , Norovirus/classificação , Filogenia , Prevalência , RNA Viral/genética , Rotavirus/genética , Infecções por Rotavirus/epidemiologia , Estações do Ano , Análise de Sequência de DNARESUMO
Although vaccines have become available, emergence and rapid transmission of new variants have added new paradigm in the coronavirus disease-2019 (COVID-19) pandemic. Weather, population and host immunity have been detected as the regulatory elements of COVID-19. This study aims to investigate the effects of weather, population and host factors on the outcome of COVID-19 and mutation frequency in Japan. Data were collected during January 2020 to February 2021. About 92% isolates were form GR clades. Variants 501Y.V1 (53%) and 452R.V1 (24%) were most prevalent in Japan. The strongest correlation was detected between fatalities and population density (rs = 0.81) followed by total population (rs = 0.72). Relative humidity had the highest correlation (rs = -0.71) with the case fatality rate. Cluster mutations namely N501Y (45%), E484K (30%), N439K (16%), K417N (6%) and T478I (3%) at spike protein have increased during January to February 2021. Above 90% fatality was detected in patients aged >60 years. The ratio of male to female patients of COVID-19 was 1.35:1. This study will help to understand the seasonality of COVID-19 and impact of weather on the outcome which will add knowledge to reduce the health burden of COVID-19 by the international organisations and policy makers.
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COVID-19/epidemiologia , Densidade Demográfica , SARS-CoV-2 , Tempo (Meteorologia) , Análise Mutacional de DNA , Genoma Viral , Humanos , Japão/epidemiologia , Mutação , SARS-CoV-2/genética , Análise Espacial , Fatores de TempoRESUMO
Virus associated diarrhea remains one of the leading causes of children morbidity and mortality in Bangladesh. Human bocavirus (HBoV) has been reported as a potential pathogen of children's diarrhea worldwide. However, due to its frequent association with other gastroenteric pathogens, its role as diarrhea causative agent remains to be defined. This study focuses to detect the incidence of HBoV and adenovirus (AdV) and to determine the molecular and epidemiological characteristics of HBoV and AdV. Between January 2015 to January 2019, 290 fecal specimens were collected from diarrheal children in Bangladesh. All fecal specimens were tested for HBoV and AdV by conventional polymerase chain reaction and sequencing methods. HBoV was detected in 7.24% (21 of 290) of the stool samples, as a sole virus in 71.42% (15 of 21) of the positive samples. AdV was detected in 4.82% (14 of 290) of the samples. The most common clinical symptoms of HBoV infected patients were diarrhea (100%) and vomiting (57%). All of the isolates of HBoV were from HBoV1 and AdV were from AdV41, AdV5, AdV7, and AdV8. To the best of our knowledge, this is the first epidemiological and molecular analysis report of HBoV from clinical specimens in Bangladesh. In the future, more studies are needed to clarify the role of HBoV as diarrheal pathogens.
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The nervous system is a crucial component of the body and damages to this system, either by injury or disease, can result in serious or potentially lethal consequences. An important problem in neural engineering is how we can stimulate the regeneration of damaged nervous tissue given its complex physiology and limited regenerative capacity. To regenerate damaged nervous tissue, this study electrospun three-dimensional nanoscaffolds (3DNSs) from a biomaterial blend of silk fibroin (SF), polyethylene glycol (PEG), and polyvinyl alcohol (PVA). The 3DNSs were characterised to ascertain their potential suitability for direct implant into the CNS. The biological activity of 3DNSs was investigated in vitro using PC12 cells and their effects on reactive astrogliosis were assessed in vivo using a photothrombotic model of ischaemic stroke in mice. Results showed that the concentration of SF directly affected the mechanical characteristics and internal structure of the 3DNSs, with formulations presenting as either a gel-like structure (SF ≥ 50%) or a nanofibrous structure (SF ≤ 40%). In vitro assessment revealed increased cell viability in the presence of the 3DNSs and in vivo assessment resulted in a significant decrease in glial fibrillary acidic protein (GFAP) expression in the peri-infarct region (p < 0.001 for F2 and p < 0.05 for F4) after stroke, suggesting that 3DNSs could be suppressing reactive astrogliosis. The findings enhanced our understanding of physiochemical interactions between SF, PEG, and PVA, and elucidated the potential of 3DNSs as a potential therapeutic approach to stroke recovery, especially if these are used in conjunction with drug or cell treatment.
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Fibroínas/química , Neurônios/metabolismo , Neurônios/fisiologia , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos , Animais , Materiais Biocompatíveis , Biofísica , Proliferação de Células , Sobrevivência Celular , Eletroquímica , Proteína Glial Fibrilar Ácida/metabolismo , Gliose/patologia , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia Eletrônica de Varredura , Nanofibras/química , Nanopartículas/química , Células PC12 , Fotoquímica , Polietilenoglicóis/química , Álcool de Polivinil/química , Ratos , Regeneração , Reologia , Seda/química , Acidente Vascular Cerebral , Trombose , Alicerces TeciduaisRESUMO
The nervous system is a crucial component of the body and damages to this system, either by of injury or disease, can result in serious or potentially lethal consequences. Restoring the damaged nervous system is a great challenge due to the complex physiology system and limited regenerative capacity.Polymers, either synthetic or natural in origin, have been extensively evaluated as a solution for restoring functions in damaged neural tissues. Polymers offer a wide range of versatility, in particular regarding shape and mechanical characteristics, and their biocompatibility is unmatched by other biomaterials, such as metals and ceramics. Several studies have shown that polymers can be shaped into suitable support structures, including nerve conduits, scaffolds, and electrospun matrices, capable of improving the regeneration of damaged neural tissues. In general, natural polymers offer the advantage of better biocompatibility and bioactivity, while synthetic or non-natural polymers have better mechanical properties and structural stability. Often, combinations of the two allow for the development of polymeric conduits able to mimic the native physiological environment of healthy neural tissues and, consequently, regulate cell behaviour and support the regeneration of injured nervous tissues.Currently, most of neural tissue engineering applications are in pre-clinical study, in particular for use in the central nervous system, however collagen polymer conduits aimed at regeneration of peripheral nerves have already been successfully tested in clinical trials.This review highlights different types of natural and synthetic polymers used in neural tissue engineering and their advantages and disadvantages for neural regeneration.
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Regeneração Nervosa/efeitos dos fármacos , Tecido Nervoso/efeitos dos fármacos , Polímeros/farmacologia , Engenharia Tecidual/métodos , Animais , Humanos , Regeneração Nervosa/fisiologia , Tecido Nervoso/fisiologiaRESUMO
Retinitis pigmentosais one of the most prevalent causes of inherited retinal dystrophies worldwide. The widespread custom of consanguineous marriages in South Asian countries puts the population at risk for autosomal recessive disorders including retinitis pigmentosa. This systematic review was done between May and December 2015.A comprehensive literature search was carried out using MEDLINE and CINAHL databases and all relevant articles on causative mutations for non-syndromic Retinitis pigmentosa from 1999 till 2015 were included. Overall, 41 articles were identified involving 66 families; 28(68%)from Pakistan, 12(29%) from India and 1(2.4%) from Bangladesh. No data was available from the rest of countries in the region. Autosomal recessive was the most common pattern of inheritance and out of the known 60 genes thought to be involved in the pathogenesis of non-syndromic Retinitis pigmentosa, 32(53%) were identified in South Asia. Although significant progress has been made in this regard, there are many more loci that are yet to be identified. Our study found that significant gaps in knowledge exist due to lack of reported literature from countries other than Pakistan and India and the absence of cost-effective screening programmes in place.
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Povo Asiático , Retinose Pigmentar , Povo Asiático/genética , Povo Asiático/estatística & dados numéricos , Bangladesh , Predisposição Genética para Doença/genética , Humanos , Índia , Mutação/genética , Retinose Pigmentar/epidemiologia , Retinose Pigmentar/genética , População Branca/genética , População Branca/estatística & dados numéricosRESUMO
This retrospective study was done to evaluate the visual and anatomic outcomes of scleral buckling for the repair of rhegmatogenous retinal detachment (RRD). All scleral buckle procedures performed at the Aga Khan University Hospital, Karachi, from May 1999 to April 2012 were included. A total of 75 eyes of 72 patients were studied. The mean age of patients at surgery was 33.0±17.2 years. The mean logarithm of the minimum angle of resolution (logMAR) visual acuity (VA) was 0.9±0.8 pre-operatively and 0.5±0.6 at 1 year (p=0.018). At baseline, 27(36%) eyes had a best corrected visual acuity (BCVA) of 20/50 or better, while at 1 year after surgery 47(63.5%) eyes had BCVA of 20/50 or better. Retina had successfully attached after first attempt in 70(93.3%) cases. Scleral buckling for the repair of RRD resulted in a high anatomical success rate as well as significant improvement in visual acuity.
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Descolamento Retiniano/cirurgia , Recurvamento da Esclera/estatística & dados numéricos , Centros de Atenção Terciária/estatística & dados numéricos , Adolescente , Adulto , Humanos , Pessoa de Meia-Idade , Paquistão , Estudos Retrospectivos , Recurvamento da Esclera/métodos , Resultado do Tratamento , Adulto JovemRESUMO
Ten MiniSTR loci were analyzed on 250 unrelated individuals of Punjabi population from Punjab province of Pakistan. The product amplification range is from 65 to 280 bp. Allele frequency for a total of 98 observed alleles is from 0.002 to 0.41. Forensic and paternity statistical parameters were investigated including combined power of discrimination (PD), combined power of exclusion (PE), and cumulative probability of matching (PM) equaled to 0.99999999999824, 0.999824, and 1.75931 × 10(-12), respectively. These MiniSTRs on the basis of high degree polymorphism and fragment size reduction will be highly informative in most of the forensic cases where DNA of the samples is degraded, mass disasters, and dead body identification. Significant differences were observed in all loci when comparing with same STR loci in previously published different world populations.
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Genética Populacional , Repetições de Microssatélites , Polimorfismo Genético , Impressões Digitais de DNA , Frequência do Gene , Humanos , Paquistão , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Two hundred individual samples of Pashtun population from Khyber Pakhtunkhwa province of Pakistan were randomly evaluated through 10 MiniSTR loci (CSF1PO, D7S820, TPOX, D18S51, D2S1338, D13S317, FGA, D5S818, D21S11, and D16S539). The PCR product size was reduced in the range of 65 to 280 bp. A total of 112 alleles were observed containing allelic frequency ranging from 0.0025 to 0.4325. Statistical values for forensic and parentage analysis were calculated including combined power of discrimination (PD), combined power of exclusion (PE), and cumulative probability of matching (PM) and equaled to 0.99999999999768, 0.99984944, and 2.33 × 10(-12), respectively. These MiniSTRs show a high degree of polymorphism information content and discriminatory power which would be helpful to resolve forensic cases and establish DNA database for major population groups of Pakistan. In contrast to different populations, significant differences were also observed on these loci.
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Sistema ABO de Grupos Sanguíneos/genética , Etnicidade/genética , Frequência do Gene/genética , Genética Populacional , Repetições de Microssatélites/genética , Éxons/genética , Triagem de Portadores Genéticos , Haplótipos , Humanos , Íntrons/genética , Masculino , Paquistão , Paternidade , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNARESUMO
The design and development of a facile synthesis approach to construct novel materials for the rapid adsorption and removal of environmental pollutants are of significant interest. In this work, we report the rational design and facile synthesis of magnetic core-shell-based microporous organic networks, Fe3O4@MON-TBPT-TEB (TTMON, achieved by reacting 2,4,6-tris(p-bromophenyl) triazine and 1,3,5-triethynylbenzene) and Fe3O4@MON-TBPM-DEBP (TDMON, achieved by reacting tetrakis (4-bromophenyl) methane and 4-4'-diethynylbiphenyl). These MONs possessed excellent dispersity, electrostatic attraction as well as plenty of π-π and hydrophobic interaction sites enabled them to efficiently absorb targeted environmental pollutants. TTMON and TDMON exhibited excellent adsorption capacities of 440 and 510 mg g-1, respectively, at 25 °C for 2,4,6-trichlorophenol (TCP). TCP, 2,4-dichlorophenol (DCP), 2-naphthol (2-NT) and 4-nitrophenol (4-NP) from aqueous solution were treated by both MONs, followed by their analysis with high-performance liquid chromatography (HPLC). For TDMON, the proposed SPE-HPLC-UV method showed an LOD of 0.03 µg L-1, LOQ of 0.11 µg L-1, and a wide linear range of 1-1000 µg L-1 for TCP. The adsorption kinetics, thermodynamics, isotherms, effect of pH and humic acid (HA), ionic strength, regeneration, and reusability of the MONs were also studied. The results revealed that the novel-designed MONs have potential applications as efficient adsorbents in sample pretreatment.
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The inherent disadvantages of traditional non-flexible aerogels, such as high fragility and moisture sensitivity, severely restrict their applications. To address these issues and make the aerogels efficient, especially for advanced medical applications, different techniques have been used to incorporate flexibility in aerogel materials. In recent years, a great boom in flexible aerogels has been observed, which has enabled them to be used in high-tech biomedical applications. The current study comprises a comprehensive review of the preparation techniques of pure polymeric-based hybrid and single-component aerogels and their use in biomedical applications. The biomedical applications of these hybrid aerogels will also be reviewed and discussed, where the flexible polymeric components in the aerogels provide the main contribution. The combination of highly controlled porosity, large internal surfaces, flexibility, and the ability to conform into 3D interconnected structures support versatile properties, which are required for numerous potential medical applications such as tissue engineering; drug delivery reservoir systems; biomedical implants like heart stents, pacemakers, and artificial heart valves; disease diagnosis; and the development of antibacterial materials. The present review also explores the different mechanical, chemical, and physical properties in numerical values, which are most wanted for the fabrication of different materials used in the biomedical fields.
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Foodborne pathogens are a major public health concern and have a significant economic impact globally. From harvesting to consumption stages, food is generally contaminated by viruses, parasites, and bacteria, which causes foodborne diseases such as hemorrhagic colitis, hemolytic uremic syndrome (HUS), typhoid, acute, gastroenteritis, diarrhea, and thrombotic thrombocytopenic purpura (TTP). Hence, early detection of foodborne pathogenic microbes is essential to ensure a safe food supply and to prevent foodborne diseases. The identification of foodborne pathogens is associated with conventional (e.g., culture-based, biochemical test-based, immunological-based, and nucleic acid-based methods) and advances (e.g., hybridization-based, array-based, spectroscopy-based, and biosensor-based process) techniques. For industrial food applications, detection methods could meet parameters such as accuracy level, efficiency, quickness, specificity, sensitivity, and non-labor intensive. This review provides an overview of conventional and advanced techniques used to detect foodborne pathogens over the years. Therefore, the scientific community, policymakers, and food and agriculture industries can choose an appropriate method for better results.
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Textile-based photocatalysts are the new materials that can be utilized as an effective sustainable solution for biochemical hazards. Hence, we aimed to develop a sustainable, cost-effective, and facile approach for the fabrication of photocatalytic fabric using graphitic carbon nitride (g-C3N4) and ferric-based multifunctional nanocomposite. Bulk g-C3N4 was prepared from urea by heating it at 500 °C for 2 h. The structure of ball-milled g-C3N4 was engineered by doping with various amounts of iron (III) chloride hexahydrate solution (0.006 mol/L) and sintered at 90 °C for 24 h to prepare g-C3N4-nanosheets/α-Fe2O3 composites. These nanocomposites have potential avenues towards rational designing of g-C3N4 for improved photocatalytic, antibacterial, and antiviral behavior. The prepared nanocomposite was characterized for its surface morphology, chemical composition, crystal structure, catalytic, antibacterial, and antiviral behavior. The fabrication of ferric doped g-C3N4 nanocomposites was characterized by SEM, EDX, FTIR, and XRD analysis. The coated fabric nanocomposite was characterized for methylene blue dye degradation under visible light, antibacterial and antiviral behavior. The developed textile-based photocatalyst has been found with very good recyclability with photocatalytic degradation of dye up to 99.9 % when compared to conventional g-C3N4 powder-based photocatalyst.
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Antimicrobial and multidrug resistance (MDR) pathogens are becoming one of the major health threats among children. Integrated studies on the molecular epidemiology and prevalence of AMR and MDR diarrheal pathogens are lacking. A total of 404 fecal specimens were collected from children with diarrhea in Bangladesh from January 2019 to December 2021. We used conventional bacteriologic and molecular sequence analysis methods. Phenotypic and genotypic resistance were determined by disk diffusion and molecular sequencing methods. Fisher's exact tests with 95% confidence intervals (CIs) was performed. Prevalence of bacterial infection was 63% (251 of 404) among children with diarrhea. E. coli (29%) was the most prevalent. E. coli, Shigella spp., V. cholerae, and Salmonella spp., showed the highest frequency of resistance against ceftriaxone (75-85%), and erythromycin (70-75%%). About 10-20% isolates of E. coli, V. cholerae and Shigella spp. showed MDR against cephem, macrolides, and quinolones. Significant association (p value < 0.05) was found between the phenotypic and genotypic resistance. The risk of diarrhea was the highest among the patients co-infected with E. coli and rotavirus [OR 3.6 (95% CI 1.1-5.4) (p = 0.001)] followed by Shigella spp. and rotavirus [OR 3.5 (95% CI 0.5-5.3) (p = 0.001)]. This study will provide an integrated insight of molecular epidemiology and antimicrobial resistance profiling of bacterial pathogens among children with diarrhea in Bangladesh.
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Escherichia coli , Quinolonas , Humanos , Criança , Bangladesh/epidemiologia , Epidemiologia Molecular , Escherichia coli/genética , Diarreia/epidemiologiaRESUMO
PURPOSE: To evaluate the incidence of retinal redetachment after the removal of silicone oil endotamponade for complicated retinal detachment and identify possible factors affecting outcome. METHODS: This is a retrospective review of 173 patients who underwent pars plana vitrectomy with silicone oil tamponade for complex retinal detachment and subsequent removal of silicone oil (ROSO). The outcome factors studied included anatomical success, best-corrected visual acuity and intraocular pressure pre- and post-ROSO. RESULTS: Anatomical success was achieved in 167 of the 173 eyes (96.5%) after ROSO. The mean duration of silicone oil tamponade was 70 ± 48 weeks (median, 56 weeks; mode, 48 weeks). The cause for primary retinal detachment was proliferative diabetic retinopathy in 36 (20.8%) and proliferative vitreoretinopathy in 137 of 173 cases (79.2%). Best-corrected visual acuity of greater than 20/100 was achieved in 83 cases (49.4%) at 3 months after ROSO. Levene's test for equality of variances was used to determine the association between previous unsuccessful retinal surgeries and redetachment (P = 0.523) and between duration of endotamponade and anatomical success (P = 0.451). CONCLUSION: The incidence of retinal redetachment after ROSO in our study was 3.46%. Aggressive removal of the vitreous base, performing retinotomies, ensuring complete silicone oil filling for adequate tamponade, and argon retinopexy can lead to low complication rates and improved outcomes.
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Drenagem/métodos , Tamponamento Interno , Descolamento Retiniano/diagnóstico , Descolamento Retiniano/etiologia , Óleos de Silicone , Vitrectomia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Pressão Intraocular/fisiologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Recidiva , Descolamento Retiniano/cirurgia , Estudos Retrospectivos , Fatores de Tempo , Acuidade Visual/fisiologia , Adulto JovemRESUMO
This study aimed to develop injectable chitosan oligosaccharide (COS) and bovine hydroxyapatite (BHA) hybrid biocomposites, and characterise their physiochemical properties for use as a dental pulp-capping material. The COS powder was prepared from chitosan through hydrolytic reactions and then dissolved in 0.2% acetic acid to create a solution. BHA was obtained from waste bovine bone and milled to form a powder. The BHA powder was incorporated with the COS solution at different proportions to create the COS-BHA hybrid biocomposite. Zirconium oxide (ZrO2) powder was included in the blend as a radiopacifier. The composite was characterised to evaluate its physiochemical properties, radiopacity, setting time, solubility, and pH. Fourier-transform infrared spectroscopic analysis of the COS-BHA biocomposite shows the characteristic peaks of COS and hydroxyapatite. Compositional analysis via ICP-MS and SEM-EDX shows the predominant elements present to be the constituents of COS, BHA, and ZrO2. The hybrid biocomposite demonstrated an average setting time of 1 h and 10 min and a pH value of 10. The biocomposite demonstrated solubility when placed in a physiological solution. Radiographically, the set hybrid biocomposite appears to be more radiopaque than the commercial mineral trioxide aggregate (MTA). The developed COS-BHA hybrid biocomposite demonstrated good potential as a pulp-capping agent exhibiting high pH, with a greater radiopacity and reduced setting time compared to MTA. Solubility of the biocomposite may be addressed in future studies with the incorporation of a cross-linking agent. However, further in vitro and in vivo studies are necessary to evaluate its clinical feasibility.
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Conventional conductive homopolymers such as polypyrrole and poly-3,4-ethylenedioxythiophene (PEDOT) have poor mechanical properties, for the solution to this problem, we tried to construct hybrid composites with higher electrical properties coupled with high mechanical strength. For this purpose, Kevlar fibrous waste, conductive carbon particles, and epoxy were used to make the conductive composites. Kevlar waste was used to accomplish the need for economics and to enhance the mechanical properties. At first, Kevlar fibrous waste was converted into a nonwoven web and subjected to different pretreatments (chemical, plasma) to enhance the bonding between fiber-matrix interfaces. Similarly, conductive carbon particles were converted into nanofillers by the action of ball milling to make them homogeneous in size and structure. The size and morphological structures of ball-milled particles were analyzed by Malvern zetasizer and scanning electron microscopy. In the second phase of the study, the conductive paste was made by adding the different concentrations of ball-milled carbon particles into green epoxy. Subsequently, composite samples were fabricated via a combination of prepared conductive pastes and a pretreated Kevlar fibers web. The influence of different concentrations of carbon particles into green epoxy resin for electrical conductivity was studied. Additionally, the electrical conductivity and electromagnetic shielding ability of conductive composites were analyzed. The waveguide method at high frequency (i.e., at 2.45 GHz) was used to investigate the EMI shielding. Furthermore, the joule heating response was studied by measuring the change in temperature at the surface of the conductive composite samples, while applying a different range of voltages. The maximum temperature of 55 °C was observed when the applied voltage was 10 V. Moreover, to estimate the durability and activity in service the ageing performance (mechanical strength and moisture regain) of developed composite samples were also analyzed.