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Benefiting from easy visualization and simultaneous detection of multiple targets, fluorescence microbeads are commonly used as fluorescence-sensing elements to detect pollutants in the environment. However, the application of fluorescence microbead-based sensor arrays is still limited because fluorescence dyes always suffer from self-quenching, photobleaching, and spectral overlap. Herein, three kinds of gold nanoclusters (Au NCs) were assembled with polystyrene microspheres (PS NPs) by electrostatic interaction to prepare fluorescence microbeads (PS-Au NCs), developing a sensor array for the simultaneous analysis of multiple metal ions. In this work, different PS-Au NCs showed an enhancing or quenching fluorescence response to various metal ions, owing to distinct binding capacities. Combined with the recognition algorithm from linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA), this sensor assay could realize single-component and multicomponent qualitative detection for 8 kinds of heavy metal ions (HMIs) including Cu2+, Co2+, Pb2+, Hg2+, and Ce3+. Particularly, the large surface area of PS NPs could provide a direct reaction microenvironment to improve the efficiency of the detection process. Meanwhile, the fluorescence property of Au NCs could also be enhanced by a partially effective aggregation-induced emission (AIE) effect to give better fluorescence signal output. Under optimal conditions, 8 kinds of heavy metals and their multicomponent mixtures could be identified at concentrations as low as 0.62 µM. Meanwhile, the analytical performance of this sensor assay in water samples was also verified, meeting the requirement of actual analysis. This study provides a great potential and practical example of single-batch, multicomponent identification for HMIs.
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Postoperative dysnatremias, characterized by imbalances in serum sodium levels, have been linked to increased resource utilization and mortality in surgical and intensive care patients. The management of dysnatremias may involve medical interventions based on changes in sodium levels. In this study, we aimed to investigate the impact of postoperative changes in natremia on outcomes specifically in patients undergoing craniotomy.We conducted a retrospective analysis of patient records from the Department of Neurosurgery at West China Hospital, Sichuan University, covering the period from January 2011 to March 2021. We compared the highest and lowest sodium values in the first 14 postoperative days with the baseline values to define four categories for analysis: no change < 5 mmol/L; decrease > 5 mmol/L; increase > 5 mmol/L; both increase and decrease > 5 mmol/L. The primary outcome measure was 30-day mortality.A total of 12,713 patients were included in the study, and the overall postoperative mortality rate at 30 days was 2.1% (264 patients). The increase in sodium levels carried a particularly high risk, with a tenfold increase (OR 10.21; 95% CI 7.25-14.39) compared to patients with minimal or no change. Decreases in sodium levels were associated with an increase in mortality (OR 1.60; 95% CI 1.11-2.23).Moreover, the study revealed that postoperative sodium decrease was correlated with various complications, such as deep venous thrombosis, pneumonia, intracranial infection, urinary infection, seizures, myocardial infarction, and prolonged hospital length of stay. On the other hand, postoperative sodium increases were associated with acute kidney injury, deep venous thrombosis, pneumonia, intracranial infection, urinary infection, surgical site infection, seizures, myocardial infarction, and prolonged hospital length of stay.Changes in postoperative sodium levels were associated with increased complications, prolonged length of hospital stay, and 30-day mortality. Moreover, the severity of sodium change values correlated with higher mortality rates.
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Infarto do Miocárdio , Pneumonia , Trombose Venosa , Humanos , Estudos Retrospectivos , Craniotomia , Convulsões/epidemiologia , SódioRESUMO
STUDY OBJECTIVE: Hypernatremia is a treatable biochemical disorder associated with significant morbidity and mortality in patients undergoing surgery. However, its impact on patients who undergo elective craniotomy is not well understood. This study aimed to investigate the prognostic implications of postoperative hypernatremia on the 30-day mortality of patients undergoing elective craniotomy. DESIGN: Retrospective cohort study. SETTING: The Department of Neurosurgery of a high-volume center. PATIENTS: Adult patients undergoing elective craniotomy except those with pituitary tumors, intracerebral hemorrhage, subarachnoid hemorrhage, or traumatic brain injury. INTERVENTIONS: None. MEASUREMENTS: Perioperative laboratory data were collected for all study participants, including sodium levels, neutrophil count, serum albumin, lymphocyte count, and blood glucose. These measurements were obtained as part of routine clinical care and provided valuable information for data analysis. MAIN RESULTS: Of the 10,223 identified elective craniotomy patients who met our inclusion and exclusion criteria, 14.9% (1519) developed postoperative hypernatremia. This population's overall postoperative 30-day mortality rate was 1.7% (175). After performing an adjusted logistic regression analysis, we found that the odds of 30-day mortality increased gradually with increasing severity of hypernatremia: 2.9 deaths (OR, 3.79; 95% CI, 2.46-5.85) in patients with mild hypernatremia, 13.9 deaths (OR, 17.73; 95% CI, 11.17-28.12) in those with moderate hypernatremia, and 38.3 deaths (OR, 67.00; 95% CI, 40.44-111.00) in those with severe hypernatremia. CONCLUSIONS: Hypernatremia is common after elective craniotomy, and its presence is associated with increased mortality and complications, particularly in cases of severe hypernatremia. These results emphasize the significance of risk evaluation in neurosurgical patients and propose the advantages of closely monitoring serum sodium levels in high-risk individuals. Future randomized controlled trials could provide more insight into the effect of treating postoperative hypernatremia in these patients.
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Hipernatremia , Adulto , Humanos , Hipernatremia/complicações , Hipernatremia/epidemiologia , Estudos Retrospectivos , Craniotomia/efeitos adversos , Prognóstico , Sódio , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologiaRESUMO
BACKGROUND: Prior studies have reported the cross-sectional relationship between lung function and arterial stiffness, while the longitudinal association remains unclear to date. This study aimed to investigate whether abnormal lung function and its subtypes at baseline are associated with increased arterial stiffness using a cohort. METHODS AND RESULTS: This was a secondary analysis extracting 2461 participants from Beijing Health Management Cohort as baseline and annually followed for development of arterial stiffness. Abnormal lung function was defined by forced expiratory volume in 1s <80% of the predicted value, forced vital capacity of the predicted value, or forced expiratory volume in 1s/forced vital capacity ratio <70%. Increased arterial stiffness was determined by brachial-ankle pulse wave velocity ≥1400 cm/s. Cox proportional hazards model was used to calculate the hazard ratio and population attributable fraction. The mean age was 42.8±8.1 years, and 444 (18.0%) cases developed increased arterial stiffness during a median follow-up of 3.0 years. The adjusted hazard ratio (95% CI) of arterial stiffness was 1.47 (95% CI, 1.10-1.96) for abnormal lung function, with a population attributable fraction of 3.9% (95% CI, 0.8-7.1). Of subtypes, only obstructive ventilatory dysfunction was significantly associated with arterial stiffness (adjusted hazard ratio, 2.06 [95% CI, 1.27-3.36]), not restricted ventilatory dysfunction (adjusted hazard ratio, 0.95 [95% CI, 0.54-1.65]). Consistent results were observed on multiple sensitivity analyses. CONCLUSIONS: Our study indicated a longitudinal association of abnormal lung function with increased arterial stiffness using a large cohort, especially for the obstructive ventilatory dysfunction.
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Índice Tornozelo-Braço , Rigidez Vascular , Humanos , Adulto , Pessoa de Meia-Idade , Estudos Longitudinais , Índice Tornozelo-Braço/métodos , Análise de Onda de Pulso/métodos , Estudos de Coortes , PulmãoRESUMO
BACKGROUND: The early detection of benign and malignant lung tumors enabled patients to diagnose lesions and implement appropriate health measures earlier, dramatically improving lung cancer patients' quality of living. Machine learning methods performed admirably when recognizing small benign and malignant lung nodules. However, exploration and investigation are required to fully leverage the potential of machine learning in distinguishing between benign and malignant small lung nodules. OBJECTIVE: The aim of this study was to develop and evaluate the ResNet50-Ensemble Voting model for detecting the benign and malignant nature of small pulmonary nodules (<20 mm) based on CT images. METHODS: In this study, 834 CT imaging data from 396 patients with small pulmonary nodules were gathered and randomly assigned to the training and validation sets in an 8:2 ratio. ResNet50 and VGG16 algorithms were utilized to extract CT image features, followed by XGBoost, SVM, and Ensemble Voting techniques for classification, for a total of ten different classes of machine learning combinatorial classifiers. Indicators such as accuracy, sensitivity, and specificity were used to assess the models. The collected features are also shown to investigate the contrasts between them. RESULTS: The algorithm we presented, ResNet50-Ensemble Voting, performed best in the test set, with an accuracy of 0.943 (0.938, 0.948) and sensitivity and specificity of 0.964 and 0.911, respectively. VGG16-Ensemble Voting had an accuracy of 0.887 (0.880, 0.894), with a sensitivity and specificity of 0.952 and 0.784, respectively. CONCLUSION: Machine learning models that were implemented and integrated ResNet50-Ensemble Voting performed exceptionally well in identifying benign and malignant small pulmonary nodules (<20 mm) from various sites, which might help doctors in accurately diagnosing the nature of early-stage lung nodules in clinical practice.
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In this study, a simultaneous fill/draw SBR was applied to investigate the feasibility of partial nitrification process with inoculation of matured aerobic granular sludge. The system operated stably over 120 days with the relatively high ammonium removal efficiency (≥ 98.83%) and nitrite accumulation rate (≥ 89.60%). Moreover, a hybrid flocs/granules system was formed stably after long-term operation. The nitrite-oxidizing bacteria (NOB) was suppressed effectively because of the combined effect of simultaneous fill/draw mode and intermittent aeration conditions. Furthermore, batch tests were separately tested with isolated granules (> 200 µm) and flocs (< 200 µm), showing that the specific ammonia oxidation rate of granules and flocs were 15.94 ± 2.85 and 66.77 ± 0.83 mg N/(g MLSS·h), respectively. Correspondingly, the abundance of Nitrosomonas as a typical AOB in granules (6.24%) and flocs (11.94%) was obtained via the microbial diversity analysis, while NOB was almost hardly detected in granules and flocs.
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Compostos de Amônio , Esgotos , Esgotos/microbiologia , Nitritos , Nitrificação , Reatores Biológicos/microbiologia , BactériasRESUMO
Establishing an effective choice architecture system enables people to improve their ability to make better food choices and encourage transformation of the food system into one that is more efficient, healthy, and sustainable. However, affecting consumer preferences by improving information supply is still a crucial issue that has not been comprehensively explored in China and many developing countries. This study aimed to identify the most effective information treatment method for increasing the likelihood of purchase and willingness to pay (WTP) for nutritionally enhanced eggs. A survey with five information treatments and a choice experiment was completed by a random sample of 2379 Chinese consumers, and the mixed logit model was subsequently applied to interpret the results. It was found that when nutritional information (NI), health benefit information (HBI), and/or market status quo information (MSQ) was presented to consumers, their utility increased. Different schemes had different effects on participants' WTP. The HBI from scientific research institution, provided in the form of leaflets, has the most significant effect on improving WTP, increasing the WTP of consumers by 31.65%. WTP for functional eggs increased similarly in response to NI and MSQ information. However, adding NI to HBI did not significantly increase the value of functional eggs, especially when the information was presented to the interviewees in the form of short videos. This research broadens the present knowledge and application of an information communication strategy by suggesting that the combination of information content, carriers, source influence consumer preference and WTP for nutritionally enhanced eggs. The results have implications for the communication practices of food enterprises to optimize their marketing strategies and improve product innovation to add more value to the functional food.
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Comportamento do Consumidor , Alimento Funcional , Humanos , Preferências Alimentares , China , Inquéritos e Questionários , Comportamento de EscolhaRESUMO
The potential contribution of nutritionally fortified foods to the improvement of public health has been recognized internationally; however, the extent of people's preferences for functional foods and the influence of information intervention on consumers' acceptance and selection of nutritious foods have not been comprehensively studied in China. The main purposes of this study are to assess Chinese consumers' perceptions towards nutritionally fortified eggs and to explore the ways in which information about the health benefits and the international market status quo of functional eggs impacts Chinese consumers' preferences and their willingness to pay (WTP) for nutritional fortification. Discrete choice experiments were used to elicit the preferences of 740 egg consumers from four cities in China, and a mixed logit model subsequently utilized to interpret the results. It was found that the provision of comprehensive information regarding the health benefits of trace elements and unsaturated fatty acids, as well as insight into the current market status quo, significantly improved participants' preferences and their WTP for functional eggs. Furthermore, the heterogeneous effects of demographic and sociocultural factors on consumers' treatment of this information were explored. It was found that the study participants with children and those with prior purchase experience exhibited a relatively stronger response to the information, while those who had expressed trust in the human health benefits of the nutritional content of functional eggs were not as sensitive as expected to the additional information. Therefore, if the government and enterprises design appropriate information treatment and nudging methods according to the current consumption characteristics of nutritionally fortified eggs, this will help to improve consumers' purchase confidence in the health efficacy of functional food and play a positive role in promoting people's healthy food consumption.
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Calcium phosphate cement (CPC) modified with native and pregelatinized normal corn and waxy maize starches was studied. Effects of starch pregelatinization and starch type on the physicochemical properties of CPC were investigated. CPC modified with pregelatinized normal corn starch (CPB-PNC) or pregelatinized waxy maize starch (CPB-PW) was evaluated by two vertebral fracture surgical models in vitro. Both granular and pregelatinized starches significantly improved the setting times and injectability of CPC, but only the pregelatinized starches improved the anti-collapsibility and compressive strength of CPC significantly. CPB-PW, whose micro-structure was compact and uniform, showed the best physicochemical properties. Addition of starch did not inhibit the hydro-reaction of CPC. Unmodified CPC had very poor dispersibility and could not apply in the tests of the surgical models. Pregelatinized starch especially waxy maize starch improved the dispersibility of CPC and showed good dispersion area, volume, improved pull-out force and maximum torque in the Sawbones sponge model. Similarly, in the minimally invasive kyphoplasty model, CPB-PNC and CPB-PW could disperse in the osteoporotic sheep vertebrae and improve the compressive strength of the sheep vertebral body. In conclusion, starch pregelatinization and starch botanical source affect the physicochemical properties of CPC significantly. Bone cements modified by different starches also performed differently in surgical models for osteoporotic vertebral fracture. Pregelatinized waxy maize starch may be a better candidate for CPC modification comparing to the pregelatinized normal corn starch.
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Cimentos Ósseos , Fraturas da Coluna Vertebral , Animais , Cimentos Ósseos/química , Fosfatos de Cálcio/química , Modelos Anatômicos , Ovinos , Fraturas da Coluna Vertebral/cirurgia , Amido/químicaRESUMO
BACKGROUND: Intervertebral disc degeneration (IDD) was considered to be the pathological basis of intervertebral disc herniation (IDH). However, the plasma melatonin in the IDD cases and healthy controls remained unclear. METHODS: In this case-control study, a total of 71 IDD cases and 54 healthy controls were enrolled between April 2020 and August 2020. The diagnostic effect of plasma melatonin for IDD was detected using receiver operating characteristic curve. The correlations between two continuous variables were detected with the Pearson linear analyses. RESULTS: It was found that lower melatonin concentration was detected in the IDD cases (1.906 ± 1.041 vs 3.072 ± 0.511 pg/mL, P<0.001). Through receiver operating characteristic curve analyses, it was found that plasma melatonin could be used as a diagnostic biomarker for IDD (area under curve=0.808, P<0.001). In advanced correlation analyses, it was found that plasma melatonin concentration was negatively associated with the age, symptom durations, IDD disease severity and proinflammatory factors, including IL-6 and TNF-α concentrations (P<0.05). Comparing with the higher melatonin groups, significantly increased IL-6 (0.601 ± 0.085 vs 0.507 ± 0.167 pg/mL, P=0.028) and TNF-α (3.022 ± 0.286 vs 2.353 ± 0.641, P<0.001) were detected in the patients with lower melatonin concentration. CONCLUSION: The plasma melatonin concentration was significantly decreased in the IDD cases and plasma melatonin could be used as a diagnostic biomarker for IDD. Lower plasma melatonin was associated with longer disease durations, elevated disease severity and higher inflammatory cytokines levels in IDD patients.
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Citocinas/biossíntese , Degeneração do Disco Intervertebral/sangue , Melatonina/biossíntese , Adulto , Fatores Etários , Idoso , Biomarcadores , Estudos de Casos e Controles , Feminino , Humanos , Mediadores da Inflamação/metabolismo , Interleucina-6/biossíntese , Degeneração do Disco Intervertebral/fisiopatologia , Masculino , Melatonina/análise , Pessoa de Meia-Idade , Estudos Prospectivos , Curva ROC , Índice de Gravidade de Doença , Fator de Necrose Tumoral alfa/biossínteseRESUMO
BACKGROUND: Intervertebral disc degeneration (IDD) is the most common diagnosis of patients with lower back pain. IDD is the underlying lesion of many spinal degenerative diseases; however, the role of cGAS/Sting/NLRP3 pathway and epigallocatechin gallate (EGCG) in the development of IDD remained unclear. METHODS: The expressions of cGAS, Sting and NLRP3 mRNA of intervertebral disc (IVD) samples from IDD patients and controls were detected by RT-PCR. The nucleus pulposus cells (NPCs) were induced by hydrogen peroxide (H2O2) and used as an in-vitro model. Both 5 µM and 25 µM EGCG treatment were used to detect the effect of EGCG on the in-vitro model. Cell viability was detected by the MTT method, and cell apoptosis and cell cycle would be detected by flow cytometry. Western blot was used in the detection of the expression of cGAS/Sting/NLRP3 as well as apoptosis-related protein level. ELISA was used in the detection of pro-inflammatory factors, including IL-1ß, TNF-α, IL-6 and IL-10. RESULTS: The expressions of cGAS, Sting and NLRP3 mRNA were significantly increased in the IVD samples from IDD patients and NLRP3 was associated with cGAS and Sting. Advanced in-vitro study showed that H2O2 significantly increased the expression of cGAS, Sting and NLRP3 protein levels. Advanced experiments showed that EGCG treatment demonstrated significant protective effects in cell viability, apoptosis, cell cycle arrest and inflammatory status through down-regulation of cGAS/Sting/NLRP3 pathway. CONCLUSION: It was shown that the cGAS, Sting and NLRP3 up-regulation was associated with the incidence of IDD. Our findings also suggest that EGCG treatment would provide anti-apoptosis, anti-inflammation and promote cell viability in H2O2 treatment-incubated NPCs through inhibiting cGAS/Sting/NLRP3 pathway.
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Apoptose/efeitos dos fármacos , Catequina/análogos & derivados , Peróxido de Hidrogênio/antagonistas & inibidores , Inflamação/prevenção & controle , Núcleo Pulposo/efeitos dos fármacos , Catequina/farmacologia , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Humanos , Inflamação/induzido quimicamente , Inflamação/metabolismo , Masculino , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Nucleotidiltransferases/antagonistas & inibidores , Nucleotidiltransferases/metabolismo , Núcleo Pulposo/metabolismo , Núcleo Pulposo/patologia , Relação Estrutura-AtividadeRESUMO
Wear debris-induced osteolysis and ensuing aseptic loosening is the main cause of implant failure and revision surgery. Wear debris-induced inflammatory response plays key roles in peri-implant osteolysis. Recently, substantial of evidence suggests that hydrogen sulfide (H2 S), the third gasotransmitter, is a critical player regulating inflammation. However, the role and therapeutic potential of H2 S in wear debris-induced inflammation and osteolysis remains to be defined. In the present study, we investigated the effect of H2 S on wear debris-induced pro-inflammatory cytokines expression and osteolysis in vitro and in vivo. With a slow-releasing H2 S donor GYY4137, our study demonstrated that H2 S attenuated wear debris-induced osteolysis and osteoclastogenesis in murine calvaria resorption models. The expression of tumor necrosis factor-alpha (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6) that stimulated by wear particles were significantly reduced by GYY4137. Further, the level of sirtuin 1 (SIRT1), which possesses anti-inflammation property, was examined in vivo and in macrophages. And we found that wear debris decreased the expression of SIRT1. Cotreated macrophages with GYY4137 in part reversed the decline of SIRT1. More importantly, with the SIRT1 recombinant lentivirus and small interfering RNAs (siRNA) against SIRT1, our data indicated that SIRT1 mediated the inhibitory effects of GYY4137 on wear debris-induced inflammation. Collectively, these results suggested that exogenous H2 S production (via H2 S donors) may represent a potential approach for the treatment of wear particle-induced osteolysis.
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Sulfeto de Hidrogênio/uso terapêutico , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Osteólise/tratamento farmacológico , Osteólise/metabolismo , Sirtuína 1/metabolismo , Animais , Western Blotting , Sobrevivência Celular/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Camundongos , Células RAW 264.7 , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/efeitos dos fármacos , Microtomografia por Raio-XRESUMO
Exposure of retinyl palmitate (RP) to ultraviolet radiation can lead to its photo-degradation and loss of biological activity. Therefore, there is a demand to explore new approaches to protect RP in an easy, economical and efficient way. The objective of this study was to explore the role of policosanol oleogels (PCOs) in the protection of RP from photodegradation. UV-blocking action was tested by placing a layer of PCO as a barrier between a UVA (365 nm) source and 1% RP in soybean oil. Effects of structural characteristics of PCOs cooled at different rates on RP photostability were also studied. The ability of PCOs to prevent radical-mediated reactions was assessed by measuring oil oxidative stability over storage time at 40 °C. The remaining % RP was measured by HPLC during 4 days of UVA irradiation. PCO blocked energy absorption from UVA and further dampened the UVA mediated ionic photodissociation and free radical reactions due to matrix immobilization. After 4 days of UV exposure, photodegradation of RP was reduced by 64% when a PCO layer was used as a barrier. Peroxide values (PV) and p-anisidine values (p-A.V.) of soybean oil (SO) were significantly higher than those of PCOs over storage time. Cooling rate processing played a significant role in RP protection; the faster the cooling rate, the higher the RP photostability. This study demonstrated that the protective mechanism of RP in PCOs is a combined effect of physical UV-barrier action, molecular immobilization and inhibition of the free radical-mediated reaction.
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Photostability of all-trans retinyl palmitate (RP) (100% bioactivity) was studied in policosanol oleogels (PCOs) (7-12% w/w policosanol in soybean oil) after UVA irradiation. RP was incorporated into PCOs at levels of 0.04%, 0.1% and 1% (w/w). PCOs efficiently protected RP from UVA-mediated degradation. Over 75% RP-activity remained in PCOs after 4â¯days of UVA irradiation, while 12% RP-activity remained in soybean oil. HPLC analysis showed that cis-RP was formed in liquid soybean oil after 2â¯days of UVA irradiation while it was absent in PCOs matrices. PCOs blocked the energy absorption from UVA and further dampened the UVA-mediated ionic photodissociation and free radical reaction due to matrix immobilization. For all samples, RP photodegradation followed a 2nd order reaction. From the reaction kinetics, it would be possible to predict the RP photodegradation rate in PCO matrices. PCOs were shown to be a promising matrix to protect RP from photodegradation.
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Álcoois Graxos/química , Fotólise , Vitamina A/análogos & derivados , Diterpenos , Álcoois Graxos/efeitos da radiação , Cinética , Compostos Orgânicos/química , Compostos Orgânicos/efeitos da radiação , Ésteres de Retinil , Raios Ultravioleta , Vitamina A/química , Vitamina A/efeitos da radiaçãoRESUMO
Artificial total hip arthroplasty (THA) is one of the most effective orthopaedic surgeries that has been used for decades. However, wear of the articulating surfaces is one of the key failure causes limiting the lifetime of total hip implant. In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed to explore the composition and formation mechanism of the tribo-layer on the articulating surfaces of metal-on-polyethylene (MoPE) implants retrieved from patients. Results showed that, in contrast to conventional understanding, the attached tribo-layer contained not only denatured proteins but also a fraction of polymer particles. The formation of the tribo-layer was believed to relate to lubrication regime, which was supposed to be largely affected by the nature of the ultra-high-molecule-weight-polyethylene (UHMWPE). Wear and formation of tribo-layer could be minimized in elasto-hydrodynamic lubrication (EHL) regime when the UHMWPE was less stiff and have a morphology containing micro-pits; whereas the wear was more severe and tribo-layer formed in boundary lubrication. Our results and analyses suggest that enhancing interface lubrication may be more effective on reducing wear than increasing the hardness of material. This finding may shed light on the design strategy of artificial hip joints.
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Prótese de Quadril , Polietilenos/química , Feminino , Humanos , Masculino , Teste de Materiais , Microscopia de Força Atômica , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de SuperfícieRESUMO
Cry proteins are expressed in rice lines for lepidopteran pest control. These proteins can be transferred from transgenic rice plants to non-target arthropods, including planthoppers and then to a predatory spider. Movement of Cry proteins through food webs may reduce fitness of non-target arthropods, although recent publications indicated no serious changes in non-target populations. Nonetheless, Cry protein intoxication influences gene expression in Cry-sensitive insects. We posed the hypothesis that Cry protein intoxication influences enzyme activities in spiders acting in tri-trophic food webs. Here we report on the outcomes of experiments designed to test our hypothesis with two spider species. We demonstrated that the movement of CryAb protein from Drosophila culture medium into fruit flies maintained on the CryAb containing medium and from the flies to the spiders Ummeliata insecticeps and Pardosa pseudoannulata. We also show that the activities of three key metabolic enzymes, acetylcholine esterase (AchE), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) were significantly influenced in the spiders after feeding on Cry1Ab-containing fruit flies. We infer from these data that Cry proteins originating in transgenic crops impacts non-target arthropods at the physiological and biochemical levels, which may be one mechanism of Cry protein-related reductions in fitness of non-target beneficial predators.
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Antioxidantes/metabolismo , Proteínas de Bactérias/metabolismo , Drosophila melanogaster/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Herbivoria/fisiologia , Aranhas/enzimologia , Acetilcolinesterase/metabolismo , Animais , Toxinas de Bacillus thuringiensis , Meios de Cultura , Glutationa Peroxidase/metabolismo , Superóxido Dismutase/metabolismoRESUMO
To assess the safety of transgenic rice expressing Cry1Ab protein to vertebrates, the effect of Cry1Ab rice on broad health indicators in blood and various organs of Swiss rats were analyzed. The 30 and 90 day safety studies of Cry1Ab rice on female Swiss rats revealed that Cry1Ab rice had no significant effect on the several elements of blood lymph including hemogram, calcium ion concentration and apoptosis rate of lymphocytes, indicating that Cry1Ab protein could not affect the blood lymph of Swiss rat. Similarly, Cry1Ab rice had no effect on enzyme activities in a variety of organs of Swiss rat. However, Cry1Ab rice did have significant effects on the blood biochemistry indexes including urea, triglyceride (TG), glutamic oxalacetic transaminase (AST) and alkaline phosphatase (ALP) after the rats were fed with Cry1Ab rice for 30 days, but not after 90 days, indicating that Cry1Ab protein may influence blood metabolism for a short duration. Quantitative real-time PCR (qPCR) analysis of the 6 genes encoding enzymes responsible for the major detoxification functions of liver revealed that Cry1Ab rice exerted no influences on the levels of these transcripts in liver of Swiss rat, indicating that significant differences registered in part of the blood biochemical parameters in the 30 day study might result from other untested organs or tissues in response to the stress of exogenous Cry1Ab protein. The results suggest that Cry1Ab protein has no significant long-term (90 day) effects on female Swiss rat.