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Esophageal cancer has a high incidence among malignancies in China, but a comprehensive picture of the status of its surgical management in China has hitherto not been available. A nationwide database has recently been established to address this issue. METHOD: A National Database was setup through a network platform, and data was collected from 70 high-volume centers (>100 esophagectomies/per year) across China. Data was entered between January 2009 and December 2014, and was analyzed in June 2015 after a minimal follow-up of 6 months for all patients. 8181 patients with complete data who received surgery for primary esophageal cancer on the Database were included in the analysis. RESULT: In this series, there were 6052 males and 2129 females, with a mean age of 60.5 years (range: 22-90 years). The pathology in 95.5% of patients was squamous cell carcinoma. The pathological stage distribution was 1.2% in stage 0, 2.5% in Ia, 11.5% in Ib, 14.8% in IIa, 36.1% in IIb, 19.3% in IIIa, 8.3% in IIIb, 6.2% in IIIc. 1800 patients (22.0%) with locally advanced disease received preoperative neoadjuvant therapy and 3592 patients (43.9%) underwent postoperative adjuvant chemotherapy and/or radiotherapy. The esophagectomies were performed through left thoracotomy approach in 5870 cases (72.6%), through right chest approach in 2215 cases (27.4%) including right thoracotomy (21.3%) and VATS (6.1%). The 30-day postoperative mortality rate was 0.6% (43 patients), and the overall postoperative complication rate was 11.6% (951 patients). The 1-, 3-, and 5-year overall survival rates were 82.6%, 61.6%, and 52.9%, respectively. CONCLUSION: This National Registry Database from high-volume centers provides a comprehensive picture of surgical management for esophageal cancer in China for the first time. Squamous cell carcinoma predominates, but there is heterogeneity with respect to the surgical approach and perioperative oncologic management. Overall, surgical mortality and morbidity rates are low, and good survival rates have been achieved due to improvement of surgical treatment technology in recent years.
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Carcinoma de Células Escamosas , Neoplasias Esofágicas , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/epidemiología , Carcinoma de Células Escamosas/cirugía , China/epidemiología , Neoplasias Esofágicas/epidemiología , Neoplasias Esofágicas/cirugía , Esofagectomía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Terapia Neoadyuvante , Estadificación de Neoplasias , Sistema de Registros , Tasa de Supervivencia , Adulto JovenRESUMEN
Objective: To investigate the epidemiological characteristics and current status of surgical management for esophageal cancer in China. Methods: A national database was setup through a network platform. The clinical data of esophageal cancer treated by surgery was collected from 70 major hospitals in China between January 2009 and December 2014. Results: Complete data of 8 181 cases of esophageal cancer patients who underwent surgery were recorded in the database and recruited in the analysis. Among them, 6 052 cases were male and 2 129 were female, the average age was 60.5 years.The epidemiological investigation results showed that 148 cases (1.8%) had history of psychological trauma, 7 527 cases (92.0%) were lower social economic status, 5 072 cases (62.0%) were short of fresh vegetables and fruits, 6 544 cases (80.0%) ate rough food frequently, 3 722 cases (45.5%) drank untreated water directly from lake or river or shallow well, 3 436 cases (42.0%) had a unhealthy eating habit, including habits of eating food fast (507 cases, 6.2%), eating hot food or drinking hot tea/soup (998 cases, 12.2%), eating fried food (1 939 cases, 23.7%), 4 410 cases (53.9%) had the habits of smoking cigarettes and 2 822 cases (34.5%) drank white wine frequently.The pathological results showed that 7 813 cases (95.5%) were squamous cell carcinoma, 267 cases were adenocarcinoma (3.3%), 25 cases were adenosquamous cell carcinoma (0.3%) and 50 cases were small cell carcinoma (0.6%). A total of 1 800 cases (22.0%) received preoperative neoadjuvant therapy due to locally advanced disease or difficulty of resection. The esophagectomies were performed through left thoracotomy approach in 5 870 cases (71.8%), through right chest approach in 2 215 cases (27.1%), and the remain 96 cases (1.2%) received surgery though other approaches.A total of 8 001 cases (97.8%) underwent radical resection, the other 180 cases (2.2%) received palliative resection. The 30-day postoperative mortality rate was 0.5%, the overall ≥ grade â ¡ postoperative complication rate was 11.6% (951 cases). The 1-yr, 3-yr, and 5-yr overall actual survival rates were 82.6%, 61.6%, and 52.9%, respectively. Conclusions: The data analysis of the national database for esophageal cancer shows that bad eating habits or eating rough food without enough nutrients, lower social and economic status, drinking white wine and smoking cigarettes frequently may be correlated with tumorigenesis of esophageal cancer. However, strong evidences produced by prospective observation studies are needed. Overall, the long-term survival of esophageal cancer patients has been improved gradually due to the application of advanced surgical techniques and reasonable multimodality treatment.
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Neoplasias Esofágicas/epidemiología , Neoplasias Esofágicas/cirugía , Esofagectomía , Fumar/efectos adversos , Adulto , Anciano , China/epidemiología , Neoplasias Esofágicas/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Terapia Neoadyuvante , Sistema de Registros , Tasa de Supervivencia , SobrevivientesRESUMEN
Objective: To investigate the spectrum and antimicrobial resistance of major pathogens causing nosocomial infections in China, 2018. Methods: Non-duplicated nosocomial cases as well as pathogens causing bloodstream infections (BSI), hospital-acquired pneumonia (HAP) and intra-abdominal infections (IAI) from 11 teaching hospitals across China were collected. The minimum inhibitory concentrations (MICs) of clinically significant strains were determined by agar dilution method or broth microdilution method. The Clinical and Laboratory Standards Institute (CLSI) M100-S29 criteria were used for interpretation, and the WHONET-5.6 software was used in data analysis. Results: A total of 1 590 cases were collected, including 831 cases from BSI, 450 cases from HAP and 309 cases from IAI. The most prevalent pathogens causing BSI were Escherichia coli (29.2%, 243/831), Klebsiella pneumoniae (16.2%, 135/831) and Staphylococcus aureus (10.1%, 84/831); the most prevalent pathogens causing IAI were E. coli (26.2%, 81/309), Enterococcus faecium (15.5%, 48/309) and K. pneumoniae (13.3%, 41/309); while Acinetobacter baumanii (24.7%, 111/450), Pseudomonas aeruginosa (20.7%, 93/450) and K. pneumoniae (16.2%, 73/450) were dominated in HAP. All S. aureus were susceptible to tigecycline, linezolid, daptomycin and glycopeptides; 77.8% (105/135) of S. aureus strains were susceptible to ceftaroline. Methicillin-resistant S. aureus (MRSA) accounted for 29.6% (40/135) of all the S. aureus, and was lower than the accounted rate of methicillin-resistant coagulase-negative Staphylococcus (MRCNS) (83.7%, 41/49). One E. faecium strain (1.1%, 1/95) resistant to vacomycin and teicoplanin and one E. faecalis strain (2.3%, 1/43) resistant to linezolid was found. The prevalence of extended-spectrum ß-lactamase (ESBL) was 56.1% (193/344) in E. coli and 22.1% (55/249) in K. pneumonia; the rate of carbapenem resistant E. coli and K. pneumonia was 4.1% (14/344) and 22.9% (57/249), respectively; the percentage of ceftazidime/avibactam resistant E. coli and K. pneumonia was 2.3% (8/344) and 2.0% (5/249), respectively; the percentage of colistin resistant E. coli and K. pneumonia was 1.5% (5/344) and 7.6% (19/249), respectively; no E. coli and K. pneumonia strains were found resistant to tigecycline. The rate of carbapenem resistant A. baumanii and P. aeruginosa were 78.9% (146/185) and 36.7% (66/180), respectively. A. baumanii showed low susceptibility to the antimicrobial agents except colistin (99.5%, 184/185) and tigecycline (91.4%, 169/185). Colistin, amikacin and ceftazidime/avibactam demonstrated high antibacterial activity against P. aeruginosa with susceptility rate of 100% (180/180), 93.3% (168/180) and 85.6% (154/180), respectively. Conclusions: Nosocomial Gram-negative pathogens show high susceptibilities to tigecycline, colistin and ceftazidime/avibactam in vitro. Antimicrobial resistance in A. baumannii is a serious problem. The prevalence of carbapenem-resistant Enterobacteriaceae has increased, which should be monitored continuously in China.
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Infección Hospitalaria , Staphylococcus aureus Resistente a Meticilina , Antibacterianos/farmacología , China/epidemiología , Infección Hospitalaria/epidemiología , Farmacorresistencia Bacteriana , Escherichia coli , Hospitales de Enseñanza , Humanos , Pruebas de Sensibilidad Microbiana , Staphylococcus aureusRESUMEN
Powerful terahertz (THz) radiation is observed from large-scale underdense preplasmas in front of a solid target irradiated obliquely with picosecond relativistic intense laser pulses. The radiation covers an extremely broad spectrum with about 70% of its energy located in the high frequency regime over 10 THz. The pulse energy of the radiation is found to be above 100 µJ per steradian in the laser specular direction at an optimal preplasma scale length around 40-50 µm. Particle-in-cell simulations indicate that the radiation is mainly produced by linear mode conversion from electron plasma waves, which are excited successively via stimulated Raman scattering instability and self-modulated laser wakefields during the laser propagation in the preplasma. This radiation can be used not only as a powerful source for applications, but also as a unique diagnostic of parametric instabilities of laser propagation in plasmas.
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Staphylococcus aureus is an important cause of bloodstream infections worldwide. We examined the prevalence of genes that encode erythromycin ribosome methylase and bacterial toxins in S. aureus collected from bloodstream infections. Sixty different S. aureus isolates were obtained from blood cultures of patients who were admitted to a Teaching Hospital in Tianjin from January 2006 to August 2011. The susceptibility of the isolates to 16 antibiotics was tested. Methicillin-resistant S. aureus (MRSA) was identified using the disk diffusion method with cefoxitin. PCR was used to detect genes that encode the staphylococcal enterotoxins, Panton-Valentine leukocidin, toxic shock syndrome toxin 1 and erythromycin ribosome methylase. Molecular analysis of the MRSA strains was done using pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome mec (SCCmec) typing. The positivity rates of mecA, ermA, ermB, and ermC in the isolates were 13/60, 10/60, 18/60, and 18/60, respectively. Among the 60 isolates, 30 harbored enterotoxin genes, with sea as the most frequent toxin gene (33%), followed by sec (15%), sed (12%), and seb (5%). The see and tst genes were not found in any of the isolates. The pvl gene was detected in four strains. Eleven MRSA isolates were of the SCCmec type III; two MRSA isolates could not be determined through SCCmec typing. PFGE analysis of the 13 MRSA isolates produced 8 distinct pulsotypes. Virulence genes and erythromycin ribosome methylase genes were highly prevalent in these isolates. The PFGE results demonstrated that the MRSA spread through cloning, mainly involving SCCmec type III.
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Genes Bacterianos/genética , Staphylococcus aureus Resistente a Meticilina/genética , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/genética , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Toxinas Bacterianas/genética , Técnicas de Tipificación Bacteriana , China , ADN Bacteriano/análisis , ADN Bacteriano/genética , Electroforesis en Gel de Campo Pulsado , Exotoxinas/genética , Frecuencia de los Genes , Hospitales de Enseñanza , Humanos , Leucocidinas/genética , Staphylococcus aureus Resistente a Meticilina/clasificación , Staphylococcus aureus Resistente a Meticilina/patogenicidad , Metiltransferasas/genética , Pruebas de Sensibilidad Microbiana , Proteínas de Unión a las Penicilinas , Reacción en Cadena de la Polimerasa , Especificidad de la Especie , Infecciones Estafilocócicas/sangre , Staphylococcus aureus/clasificación , Staphylococcus aureus/patogenicidad , Virulencia/efectos de los fármacos , Virulencia/genéticaRESUMEN
Neuraminidase (NA) is a critical enzyme of the influenza virus and many inhibitors targeting this enzyme are quite efficient anti-influenza agents. In this paper, quantitative structure-activity relationship (QSAR) method was used to predict the activity of different kinds of 46 NA inhibitors. Heuristic method (HM) and radial basis function network (RBFNN) were first used to build linear and nonlinear models, respectively. The prediction results were in agreement with the experimental value. The proposed model is simple and can be extended to other QSAR investigations.
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Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Neuraminidasa/antagonistas & inhibidores , Relación Estructura-Actividad Cuantitativa , Modelos Lineales , Modelos Biológicos , Neuraminidasa/química , Neuraminidasa/metabolismoRESUMEN
BACKGROUND: Previously, high levels of CXCR3+ T-cell recruitment was demonstrated in the prolonged ischemia-accelerated acute allograft rejection in rat kidney transplant. In the present study, the effect of chemokine IP-10 was investigated and the expression of chemokine-related PRINS (Psoriasis susceptibility-related RNA gene induced by stress) lncRNA determined in the allografts subjected to ischemia. METHODS: F344-to-Lewis rat kidney transplantation was performed, and renal grafts were stored for 2 hours or 16 hours. Samples were removed at 24 hours and 7 days after operation. Cellular infiltration was determined with the use of immunohistochemistry, and messenger RNA expression was assessed with the use of real-time polymerase chain reaction. RESULTS: The 16-hour-ischemia kidney displayed acute tubule damage and up-regulation of PRINS lncRNA expression. On day 7, IP-10 expression and CD3-positive T cells were increased in allografts compared with control samples, which were inhibited by the IP-10 antibody treatment accompanied by reduced serum creatinine. CONCLUSIONS: These observations provide evidence for IP-10 in a regulatory role in cold ischemia-elicited acute allograft rejection and in PRINS lncRNA expression. Our data enhance the understanding of the mechanism underlying between prolonged ischemia and acute rejection.
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Quimiocina CXCL10/metabolismo , Rechazo de Injerto/genética , Rechazo de Injerto/inmunología , Trasplante de Riñón , ARN Largo no Codificante/biosíntesis , Aloinjertos/metabolismo , Animales , Isquemia Fría/efectos adversos , Regulación de la Expresión Génica/inmunología , Masculino , Ratas , Ratas Endogámicas F344 , Ratas Endogámicas Lew , Linfocitos T/inmunología , Trasplante HomólogoRESUMEN
Amorphous carbon nanotubes (a-CNTs) are synthesized by pyrolysis of ferrocene confined in the nanopores of the anodic alumina membrane (AAM) and characterized by field emission scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), electron energy-loss spectroscopy (EELS), and Raman spectroscopy. It is shown that the a-CNT has an ultrathin amorphous wall (approximately 3 nm) and a relatively large diameter (approximately 50 nm), and is capsulated with iron oxide nanoparticles. It is found that the growth of the a-CNTs is governed mainly by the template limitation effect. Electrical transport measurements on individual a-CNTs demonstrate that the a-CNT may be connected with electrodes via either ohmic or Schottky contacts, and the resisitivity of the a-CNTs was measured to be 4.5 x 10(-3) Omega cm.
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As a new method, support vector machine (SVM) were applied for prediction of toxicity of different data sets compared with other two common methods, multiple linear regression (MLR) and RBFNN. Quantitative structure-activity relationships (QSAR) models based on calculated molecular descriptors have been clearly established. Among them, SVM model gave the highest q(2) and correlation coefficient R. It indicates that the SVM performed better generalization ability than the MLR and RBFNN methods, especially in the test set and the whole data set. This eventually leads to better generalization than neural networks, which implement the empirical risk minimization principle and may not converge to global solutions. We would expect SVM method as a powerful tool for the prediction of molecular properties.
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Algoritmos , Contaminantes Ambientales/toxicidad , Biología Computacional/métodos , Bases de Datos como Asunto , Dosificación Letal Mediana , Modelos Lineales , Redes Neurales de la Computación , Relación Estructura-Actividad Cuantitativa , Reproducibilidad de los ResultadosRESUMEN
Prediction of toxicity of 203 nitro- and cyano-aromatic chemicals to Tetrahymena pyriformis was carried out by radial basis function neural network, general regression neural network and support vector machine, in non-linear response surface methodology. Toxicity was predicted from hydrophobicity parameter (log Kow) and maximum superdelocalizability (Amax). Special attention was drawn to prediction ability and robustness of the models, investigated both in a leave-one-out and 10-fold cross validation (CV) processes. The influence that the corresponding changes in the learning sets during these CV processes could have on a common external test set including 41 compounds was also examined. This allowed us to establish the stability of the models. The non linear results slightly outperform (as expected) multilinear relationships (MLR) and also favourably compete with various other non linear approaches recently proposed by Ren (J. Chem. Inf. Comput. Sci., 43 1679 (2003)).
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Redes Neurales de la Computación , Dinámicas no Lineales , Relación Estructura-Actividad Cuantitativa , Tetrahymena pyriformis/efectos de los fármacos , Animales , Análisis de RegresiónRESUMEN
There are few data on the molecular epidemiology of cryptococcosis in China. Here we investigated the species distribution, molecular types and antifungal susceptibilities of 312 Cryptococcus neoformans species complex isolates from ten hospitals over 5 years. Isolates were identified by internal transcribed spacer (ITS) sequencing and by two matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems. Multilocus sequence typing (MLST) was used to verify species/variety and to designate molecular types. Susceptibility to six antifungal drugs was determined by the Sensititre YeastOne™ method. Cryptococcus neoformans was the predominant species (305/312 isolates (97.8%), all were ITS type 1, serotype A), of which 89.2% (272/305) were C. neoformans var. grubii MLST sequence type (ST) 5 and 6.2% (19/305) were ST31. Other C. neoformans var. grubii STs were rare but included six novel STs. Only two strains were C. neoformans var. neoformans (both serotype AD). Cryptococcus gattii was uncommon (n = 7, four ITS types) and comprised five MLST STs including one novel ST. For C. neoformans var. grubii, the proportion of isolates with non-wild-type MICs to fluconazole significantly rose in the fourth study year (from 0% (0/56 isolates) in the first year to 23.9% (17/71) in the fourth year), including five isolates with fluconazole MICs of ≥32 mg/L. The study has provided useful data on the species epidemiology and their genetic diversity and antifungal susceptibility. The proportional increase in isolates with non-wild-type MICs to fluconazole is noted.
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Cryptococcus neoformans/clasificación , Cryptococcus neoformans/aislamiento & purificación , Tipificación de Secuencias Multilocus/métodos , Técnicas de Tipificación Micológica/métodos , Antifúngicos/farmacología , China/epidemiología , Cryptococcus neoformans/efectos de los fármacos , Cryptococcus neoformans/genética , ADN de Hongos/análisis , Fluconazol/farmacología , Humanos , Pruebas de Sensibilidad Microbiana , Filogenia , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
With the aim of gathering temporal trends on bacterial epidemiology and resistance from multiple laboratories in China, the CHINET surveillance system was organized in 2005. Antimicrobial susceptibility testing was carried out according to a unified protocol using the Kirby-Bauer method or automated systems. Results were analyzed according to Clinical and Laboratory Standards Institute (CLSI) 2014 definitions. Between 2005 and 2014, the number of bacterial isolates ranged between 22,774 and 84,572 annually. Rates of extended-spectrum ß-lactamase production among Escherichia coli isolates were stable, between 51.7 and 55.8%. Resistance of E. coli and Klebsiella pneumoniae to amikacin, ciprofloxacin, piperacillin/tazobactam and cefoperazone/sulbactam decreased with time. Carbapenem resistance among K. pneumoniae isolates increased from 2.4 to 13.4%. Resistance of Pseudomonas aeruginosa strains against all of antimicrobial agents tested including imipenem and meropenem decreased with time. On the contrary, resistance of Acinetobacter baumannii strains to carbapenems increased from 31 to 66.7%. A marked decrease of methicillin resistance from 69% in 2005 to 44.6% in 2014 was observed for Staphylococcus aureus. Carbapenem resistance rates in K. pneumoniae and A. baumannii in China are high. Our results indicate the importance of bacterial surveillance studies.
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Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Bacterias Gramnegativas/aislamiento & purificación , Infecciones por Bacterias Gramnegativas/epidemiología , China/epidemiología , Bacterias Gramnegativas/efectos de los fármacos , Infecciones por Bacterias Gramnegativas/microbiología , Humanos , Pruebas de Sensibilidad Microbiana , Vigilancia de la PoblaciónRESUMEN
Probabilistic neural networks (PNNs) were utilized for the classifications of 102 active compounds from diverse medicinal plants with anticancer activity against human rhinopharyngocele cell line KB. Molecular descriptors calculated from structure alone were used to represent molecular structures. A subset of the calculated descriptors selected using factor correlation analysis and forward stepwise regression was used to construct the prediction models. Linear discriminant analysis (LDA) was also utilized to construct the classification model to compare the results with those obtained by PNNs. The accuracy of the training set, the cross-validation set, and the test set given by PNNs and LDA were 100, 92.3, 90.9% and 71.8, 92.3, 54.5%, respectively, which indicated that the results obtained by PNNs agree well with the experimental values of these compounds and also revealed the superiority of PNNs over LDA approach for the classification of anticancer activities of compounds. The models built in this work would be of potential help in the design of novel and more potent anticancer agents.
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Redes Neurales de la Computación , Extractos Vegetales/química , Plantas Medicinales/química , Algoritmos , Antineoplásicos/química , Antineoplásicos/clasificación , Antineoplásicos/farmacología , Modelos Lineales , Modelos Teóricos , Estructura Molecular , Extractos Vegetales/clasificación , Extractos Vegetales/farmacología , Relación Estructura-Actividad CuantitativaRESUMEN
A large data set of 146 natural, synthetic and environmental chemicals belonging to a broad range of structural classes have been tested for their relative binding affinity (expressed as log (RBA)) to the androgen receptor (AR). These chemicals commonly termed endocrine disrupting compounds (EDCs) present a variety of adverse effects in humans and animals. As assays for binding affinity remains a time-consuming task, it is important to develop predictive methods. In this work, quantitative structure-activity relationships (QSARs) were determined using three methods, multiple linear regression (MLR), radical basis function neural network (RBFNN) and support vector machine (SVM). Five descriptors, accounting for hydrogen-bonding interaction, distribution of atomic charges and molecular branching degree, were selected from a heuristic method to build predictive QSAR models. Comparison of the results obtained from three models showed that the SVM method exhibited the best overall performances, with a RMS error of 0.54 log (RBA) units for the training set, 0.59 for the test set, and 0.55 for the whole set. Moreover, six linear QSAR models were constructed for some specific families based on their chemical structures. These predictive toxicology models, should be useful to rapidly identify potential androgenic endocrine disrupting compounds.
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Glándulas Endocrinas/efectos de los fármacos , Relación Estructura-Actividad Cuantitativa , Receptores Androgénicos/metabolismo , Algoritmos , Fenómenos Químicos , Química Física , Simulación por Computador , Enlace de Hidrógeno , Ligandos , Modelos Lineales , Matemática , Modelos Químicos , Redes Neurales de la Computación , Reproducibilidad de los ResultadosRESUMEN
The 3D QSAR analyses of antimalarial alkoxylated and hydroxylated chalcones were first conducted by Comparative molecular field analysis (CoMFA) and Comparative similarity indices analysis (CoMSIA) to determine the factors required for the activity of these compounds. Satisfactory results were obtained after performing a leave-one-out (LOO) cross-validation study with cross-validation q(2) and conventional r(2) values of 0.740 and 0.972 by the CoMFA model, 0.714 and 0.976 by the CoMSIA model, respectively. The results provided the tools for predicting the affinity of related compounds, and for guiding the design and synthesis of novel and more potent antimalarial agents.
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Antimaláricos/química , Chalcona/análogos & derivados , Chalcona/química , Relación Estructura-Actividad Cuantitativa , Antimaláricos/farmacología , Chalcona/farmacología , Simulación por Computador , Diseño de Fármacos , Modelos Químicos , Modelos Moleculares , Análisis Multivariante , Valor Predictivo de las PruebasRESUMEN
It is proposed for the first time a method of prediction of the programmed-temperature retention times of components of naphthas in capillary gas chromatography using artificial neural networks. People are used to predict the programmed-temperature retention time using many formulas such as the integral formula, which requires that four parameters must be determined by calculation or experiments. However the results obtained by the formula are not so good to meet the demand of industry. In order to predict retention time accurately and conveniently, artificial neural networks using five-fold cross-validation and leave-20%-out methods have been applied. Only two parameters: density and isothermal retention index were used as input vectors. The average RMS error for predicted values of five different networks was 0.18, whereas the RMS error of predictions by the integral formula was 0.69. Obviously, the predictions by neural networks were much better than predictions by the formula, and neural networks need fewer parameters than the formula. So neural networks can successfully and conveniently solve the problem of predictions of programmed-temperature retention times, and provide useful data for analysis of naphthas in petrochemical industry.
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Naftalenos/metabolismo , Redes Neurales de la Computación , Industria Química , Cromatografía de Gases , Predicción , Modelos Teóricos , Sensibilidad y Especificidad , TemperaturaRESUMEN
OBJECTIVE: To evaluate the prophylactic effect of artesunate in high-risk populations who had contacted the infested water. METHODS: From the 7th day post-exposure to infested water, a total of 17,031 people who had contacted the infested water for more than 20 days had been treated with artesunate at a dose of 300 mg once a week for three successive weeks. On day 17 after the last medication, they were examined for schistosomiasis and followed-up 60 days later. RESULTS: No acute schistosomiasis case was found. ELISA-positive was found in 204(1.20%) and COPT > 3% was found in 195 cases (1.14%). The side-effects were slight. CONCLUSION: Artesunate is highly effective and safe for the prevention of schistosomiasis.
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Antimaláricos/uso terapéutico , Artemisininas/uso terapéutico , Desastres , Esquistosomiasis Japónica/prevención & control , Sesquiterpenos/uso terapéutico , Adolescente , Adulto , Artesunato , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Hard X-ray sources from femtosecond (fs) laser-produced plasmas, including the betatron X-rays from laser wakefield-accelerated electrons, have compact sizes, fs pulse duration and fs pump-probe capability, making it promising for wide use in material and biological sciences. Currently the main problem with such betatron X-ray sources is the limited average flux even with ultra-intense laser pulses. Here, we report ultra-bright betatron X-rays can be generated using a clustering gas jet target irradiated with a small size laser, where a ten-fold enhancement of the X-ray yield is achieved compared to the results obtained using a gas target. We suggest the increased X-ray photon is due to the existence of clusters in the gas, which results in increased total electron charge trapped for acceleration and larger wiggling amplitudes during the acceleration. This observation opens a route to produce high betatron average flux using small but high repetition rate laser facilities for applications.