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The wide use of crystalline silicon solar cells in the field of new energy is an important boost for China to achieve the environmental protection goal as soon as possible. However, the production and manufacturing processes of these cells give rise to various occupational hazards at workplace, thus posing health risks to workers. This review provided an overview of production processes of crystalline silicon solar cells, the characteristics of occupational health hazards (productive dust; physical factors, productive toxicant) and proposed occupational protection suggestions.
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Exposición Profesional , Silicio , Energía Solar , Silicio/efectos adversos , Humanos , Polvo/análisis , China , Industria Manufacturera , Lugar de Trabajo , Salud LaboralRESUMEN
Objective: To analyze the effects of electrical acoustic stimulation (EAS) on speech and tone recognition as well as music perception in children with low-frequency residual hearing (LFRH) after cochlear implant (CI). Methods: A total of twelve Mandarin patients with LFRH who underwent unilateral CI from January 2017 to October 2020 were recruited, including 8 males and 4 females. There were 5 cases of pre-lingual deafness and 7 cases of post-lingual deafness. The median age at implantation was 12 years old (3-62 years). All patients had residual hearing (RH) before surgery, wore hearing aid (HA) timely, had an effective rehabilitation and the duration of use of electrical stimulation was 37.0±16.2 months. On the implanted side, the thresholds of 125 Hz and 250 Hz were less than and equal to 80 dB HL after implantation. A two-month follow-up clinical study was conducted with the EAS devices. The EAS effects were evaluated before, immediately after and 2 months after upgrade, including speech recognition rate, tone recognition and music tests. SPSS 23.0 software was used for statistical analysis. Results: A total of ten patients completed a two-month clinical follow-up and efficiency evaluation. Compared to the electrical stimulation, the recognition rate of spondee word significantly decreased after the immediate use of EAS (71.7±4.3 vs 79.6±3.1, P=0.018). Compared to the electrical stimulation as well as immediate use of EAS, the results of sentence in noise, tone in noise, and SRT of sentence in noise were all significantly improved at 2 months after use of EAS (P<0.05). The pitch discrimination was significantly improved at 2 months after the use of EAS compared with that before the use of EAS (P=0.042). Compared with before (P=0.021) and immediately (P=0.017) use of EAS, the ability of rhythm resolution was significantly improved. There were no significant differences in other test results (P>0.05). Conclusions: The low-frequency acoustic information provided by EAS as well as the electrical-acoustic stimulation mode can provide rich auditory cues of speech perception in noise, tone recognition in noise, and musical discrimination for CI subjects. It can promote the improvement of complex listening ability of CI patients undergoing long-term electrical stimulation in a short time and comprehensively improve their hearing capacities.
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Implantes Cocleares , Sordera , Niño , Femenino , Masculino , Humanos , Estimulación Acústica , Audición , Acústica , Estimulación Eléctrica , Sordera/cirugía , Hormona Liberadora de GonadotropinaRESUMEN
Objective: To explore the effect of tracheotomy combined with thyrocricocentesis and puncture of front tracheal wall in emergency treatment of laryngeal edema in patients with burns. Methods: From November 2000 to August 2018, 22 patients with severe burn or extremely severe burn combined with acute laryngeal edema were rescued in the author's unit, including 18 males and 4 females, aged 17 to 68 years. All patients were complicated with mild inhalation injury or above and more than deep partial-thickness burn to head, face, and neck. From November 2000 to October 2012, simple emergency tracheotomy was performed for 12 cases. From May 2013 to August 2018, tracheotomy combined with thyrocricocentesis and puncture of front tracheal wall was performed for 10 cases. Rescue effect and complication of the two kinds of tracheotomy were recorded. Data were processed with Fisher's exact probability test. Results: Among the 12 patients treated with simple emergency tracheotomy, 5 cases survived and 7 cases died of suffocation during tracheotomy. Among the 10 patients treated with tracheotomy combined with thyrocricocentesis and puncture of front tracheal wall, 9 cases survived and 1 case died of cardiac arrest caused by arrhythmia. There was statistically significant difference in successful rescue effect between the two kinds of tracheotomy (P<0.05). Among the 14 patients who were successfully rescued, symptoms of insomnia and post-traumatic stress disorder occurred in 12 cases, which were relieved after symptomatic treatment for 14 to 45 d without permanent hypoxic brain damage. Conclusions: In case of loss of the condition of preventive tracheotomy, first aid of acute laryngeal edema of burn patient is very difficult. Tracheotomy combined with thyrocricocentesis and puncture of front tracheal wall is simple and rapid with high successful rate and amelioration of hypoxia, which is an ideal plan for laryngeal edema.
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Obstrucción de las Vías Aéreas , Quemaduras/cirugía , Tratamiento de Urgencia , Edema Laríngeo/cirugía , Traqueotomía , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Punciones , Adulto JovenRESUMEN
The evolution of topological magnetic domains microscopically correlates the dynamic behavior of memory units in spintronic application. Nanometric bubbles with variation of spin configurations have been directly observed in a centrosymmetric hexagonal magnet (Mn0.5Ni0.5)65(Ga1-yYy)35 (y = 0.01) using Lorentz transmission electron microscopy. Magnetic bubbles instead of biskyrmions are generated due to the enhancement of quality factor Q caused by the substitution of rare-earth element Y. Furthermore, the bubble density and diversified spin configurations are systematically manipulated via combining the electric current with perpendicular magnetic fields. The magnetic bubble lattice at zero field is achieved after the optimized manipulation.
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Introducing and modulating the oxygen deficiency concentration have been received as an effective way to obtain high catalytic activity in perovskite oxides. However, it is difficult to control the oxygen vacancy in conventional oxygen defect engineering due to harsh reaction conditions at elevated temperatures and the reducing atmosphere, which make it impractical for many technological applications. Herein, we report a new approach to oxygen defect engineering based on the combination of the current effect and temperature cycling at low temperature. Our investigations revealed that the electrical conductivity of the (011)-La0.7Sr0.3CoO3/PMN-PT film changes continuously from metallicity to insulativity under repeated transport measurements below room temperature, which indicates the transformation of the Co4+ state to Co3+ in the film. Further experiments and analysis revealed that oxygen vacancies can be well regulated by the combined current effect and temperature cycling in repeated measurements, which results in a decrease of Co4+/Co3+ and thus the remarkable variation of conductive properties of the film. Our work provides a simple and highly efficient method to engineer oxygen vacancies in perovskite-type oxides and brings new opportunities in designing high-efficiency oxidation catalysts.
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We report the discovery of a new fluoride-arsenide bulk diluted magnetic semiconductor (Ba,K)F(Zn,Mn)As with the tetragonal ZrCuSiAs-type structure which is identical to that of the "1111" iron-based superconductors. The joint hole doping via (Ba,K) substitution &spin doping via (Zn,Mn) substitution results in ferromagnetic order with Curie temperature up to 30 K and demonstrates that the ferromagnetic interactions between the localized spins are mediated by the carriers. Muon spin relaxation measurements confirm the intrinsic nature of the long range magnetic order in the entire volume in the ferromagnetic phase. This is the first time that a diluted magnetic semiconductor with decoupled spin and charge doping is achieved in a fluoride compound. Comparing to the isostructure oxide counterpart of LaOZnSb, the fluoride DMS (Ba,K)F(Zn,Mn)As shows much improved semiconductive behavior that would be benefit for further application developments.
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The Wnt signaling pathway plays a key role in insurgence and progression of many different forms of cancer. Some crucial components of the Wnt pathway have been proposed to be novel targets for cancer therapy. To date, the Wnt signaling pathway has not been studied in cutaneous squamous cell carcinoma (CSCC). This study was designed to investigate the expression of Wnt1 and SFRP1 from the Wnt pathway in CSCC. Tissue samples were obtained from 35 patients with CSCC and 30 controls admitted to the Xinjiang Uygur Autonomous Region People's Hospital at Urumchi City, China. Gene and protein expressions of Wnt1 and SFRP1 were quantified by immunohistochemistry and western blotting. Wnt1 expression was significantly higher (P < 0.05) in CSCC samples than in normal skin cells of the control subjects; in contrast, SFRP1 expression was significantly lower in CSCC tissues than that in tissues of control subjects (P < 0.05). Moreover, Wnt1 expression (P < 0.05) was found to be correlated with histopathological differentiation in CSCC, and negatively correlated with SFRP1 expression in CSCC (rs = -0.473, P = 0.015). Therefore, we concluded that Wnt1 and SFRP1 play important roles in the development of CSCC and could be potent markers for diagnosis, prevention, and therapy of CSCC.
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Biomarcadores de Tumor/genética , Carcinoma de Células Escamosas/genética , Péptidos y Proteínas de Señalización Intercelular/genética , Proteínas de la Membrana/genética , Neoplasias Cutáneas/genética , Proteína Wnt1/genética , Adulto , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/metabolismo , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Estudios de Casos y Controles , Humanos , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Proteínas de la Membrana/metabolismo , Persona de Mediana Edad , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/patología , Proteína Wnt1/metabolismoRESUMEN
The PrGa compound shows excellent performance on the magnetocaloric effect (MCE) and magnetoresistance (MR). The physical mechanism of MCE and MR in PrGa compound was investigated and elaborated in detail on the basis of magnetic measurement, heat capacity measurement and neutron powder diffraction (NPD) experiment. New types of magnetic structure and magnetic transition are found. The results of the NPD along with the saturation magnetic moment (MS) and magnetic entropy (SM) indicate that the magnetic moments are randomly distributed within the equivalent conical surface in the ferromagnetic (FM) temperature range. PrGa compound undergoes an FM to FM transition and an FM to paramagnetic (PM) transition as temperature increases. The magnetizing process was discussed in detail and the physical mechanism of the magnetic field controlled magnetocaloric effect (MCE) and the magnetoresistance (MR) was studied. The formation of the plateau on MCE curve was explained and MR was calculated in detail on the basis of the magnetic structure and the analysis of the magnetizing process. The experimental results are in excellent agreement with the calculations. Finally, the expression of MR = ß(T)X(2) and its application conditions were discussed, where X is M(H)/Meff, and Meff is the paramagnetic effective moment.
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OBJECTIVE: This study aims to evaluate the efficacy and safety of α-lipoic acid in the treatment of aged type 2 diabetes mellitus (T2DM) complicated with acute cerebral infarction. PATIENTS AND METHODS: 90 patients were randomly divided into two groups, on the basis of conventional treatment. The experiment group was administrated with α-lipoic acid, while only Vitamin C for the control group, for 3 consecutive weeks. Before and after the experiment, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) levels were measured and scored with the NIHSS (National Institutes of Health Stroke Scale), and the changes of blood glucose, insulin function and other indicators were observed. RESULTS: After the treatment, the plasma SOD and GSH-Px levels increased, while MDA decreased (p < 0.05), with statistical significance when compared with the control group (p < 0.01). NIHSS score, blood glucose, blood lipids and HOMA-IA of the experiment group decreased significantly (p < 0.01); and no significant adverse reactions were found in both groups. CONCLUSIONS: α-lipoic acid was safe and effective in the treatment of aged T2DM complicated with acute cerebral infarction, significantly reducing the patient's oxidative stress, blood glucose and lipid levels and being able to improve islet function.
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Envejecimiento/efectos de los fármacos , Antioxidantes/uso terapéutico , Infarto Cerebral/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Ácido Tióctico/uso terapéutico , Enfermedad Aguda , Anciano , Envejecimiento/sangre , Envejecimiento/patología , Antioxidantes/farmacología , Ácido Ascórbico/farmacología , Ácido Ascórbico/uso terapéutico , Glucemia/efectos de los fármacos , Glucemia/metabolismo , Infarto Cerebral/sangre , Infarto Cerebral/complicaciones , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/complicaciones , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Ácido Tióctico/farmacología , Resultado del TratamientoRESUMEN
The present study deals with the synthesis and characterization of tamoxifen-loaded magnetite/poly(l-lactic acid) composite nanoparticles (TMCN), and their in vitro anti-cancer activity against MCF-7 breast cancer cells. The composite nanoparticles with an average size of approximately 200 nm, were synthesized via a solvent evaporation/extraction technique in an oil/water emulsion. The superparamagnetic property (saturation magnetization value of approximately 7 emu/g) of the TMCN is provided by Fe(3)O(4) nanoparticles of approximately 6 nm encapsulated in the poly(l-lactic acid) matrix. The encapsulation efficiency of the Fe(3)O(4) and tamoxifen as a function of the concentration in the organic phase was investigated. The uptake of TMCN and tamoxifen by MCF-7 was estimated from the intracellular iron concentration. After 4h incubation of MCF-7 with TMCN, significant changes in the cell morphology were discernible from phase contrast microscopy. Cytotoxicity assay shows that while the Fe(3)O(4)-loaded poly(l-lactic acid) composite nanoparticles exhibit no significant cytotoxicity against MCF-7, approximately 80% of the these cells were killed after incubation for 4 days with TMCN.
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Antineoplásicos , Portadores de Fármacos/química , Óxido Ferrosoférrico , Ácido Láctico , Nanopartículas/química , Polímeros , Tamoxifeno , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral/efectos de los fármacos , Forma de la Célula , Antagonistas de Estrógenos/química , Antagonistas de Estrógenos/farmacología , Óxido Ferrosoférrico/química , Óxido Ferrosoférrico/farmacología , Humanos , Ácido Láctico/química , Ácido Láctico/farmacología , Nanopartículas/ultraestructura , Tamaño de la Partícula , Poliésteres , Polímeros/química , Polímeros/farmacología , Tamoxifeno/química , Tamoxifeno/farmacologíaRESUMEN
A simple method was developed to prepare polymeric microbeads with antibacterial and antifungal properties. The microbeads of approximately spherical shape and narrow size distribution were prepared from a mixture of poly (4-vinyl pyridine) (P4VP) and poly (vinylidene fluoride) (PVDF) by a phase inversion technique and subsequently derivatized with alkyl bromides having 4-10 carbon atoms. The quaternization of the pyridine groups into pyridinium groups confers the surface with highly effective and long-lasting antibacterial and antifungal properties, as shown by the effect on Escherichia coli and Aspergillus niger. Upon contact with the N-alkylated beads, the bacteria and fungal spores are lysed and intracellular constituents leach out into the medium. The efficacy of the alkyl chains in disrupting the cell membrane was investigated. The stability of the functional group and microbiocidal effectiveness of the microbeads in repeated applications was also assessed.
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Antibacterianos/farmacología , Antifúngicos/farmacología , Aspergillus niger/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Microesferas , Antibacterianos/química , Antifúngicos/química , Aspergillus niger/ultraestructura , Polivinilos/químicaRESUMEN
OBJECTIVE: Estrogen-dependent growth of breast cancer can be blocked by anti-estrogens. Estrogen receptor (ER) presence in breast cancer implies responsiveness to endocrine therapy. However, for those patients who ultimately develop resistance to endocrine therapy, the mechanisms remain unclear. The present study attempted to compare the expression status of ER mRNA in a series of primary breast tumors with matched metastases and explored the relation between ER and mutant p53 expression. METHODS: In situ hybridization using a digoxigenin-labeled estrogen receptor cDNA probe was employed to determine the expression of ER mRNA in 52 cases of primary tumors and their matched axillary lymph node metastases. Immunohistochemical staining using a monoclonal antibody against ER was also performed. RESULTS: ER expression was observed in 53.8% (28/52) of primary tumors and 48% (25/52) of metastases, while 57.7% (30/52) of primary tumors and 53.8% (28/52) of metastases showed ER mRNA positivity. There were variations in ER status between in situ hybridization and immunohistochemistry measurements and between primary tumors and metastases. Mutant p53 expression was inversely associated with ER-negative, high-grade tumors. CONCLUSIONS: In situ hybridization may be a more specific and sensitive method for determination of ER status than immunohistochemistry. It is possible that the biologic properties of ER change, and these changes may influence tumor response to endocrine therapy. In view of the ER variation, it was suggested that the ER status of metastatic tumors in addition to primary tumors should be taken into consideration in order to better determine the benefit of clinical endocrine therapy.