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1.
Environ Pollut ; 260: 114084, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32041033

RESUMO

Northern China is a significant source of dust source in Central Asia. Thus, high-resolution analysis of dust storms and comparison of dust sources in different regions of northern China are important to clarify the formation mechanism of East Asian dust storms and predict or even prevent such storms. Here, we analyzed spatiotemporal trends in dust storms that occurred in three main dust source regions during 1960-2007: Taklimakan Desert (western region [WR]), Badain Jaran and Tengger Deserts (middle region [MR]), and Otindag Sandy Land (eastern region [ER]). We analyzed daily dust storm frequency (DSF) at the 10-day scale (first [FTDM], middle [MTDM], and last [LTDM] 10 days of a month), and investigated the association of dust storm occurrences with meteorological factors. The 10-day DSF was greatest in the FTDM (accounting for 77.14% of monthly occurrences) in the WR, MTDM (45.85%) in the MR, and LTDM (72.12%) in the ER, showing a clear trend of movement from the WR to the ER. Temporal analysis of DSF revealed trend changes over time at annual and 10-day scales, with mutation points at 1985 and 2000. We applied single-factor and multiple-factor analyses to explore the driving mechanisms of DSF at the 10-day scale. Among single factors, a low wind-speed threshold, high solar radiation, and high evaporation were correlated with a high DSF, effectively explaining the variations in DSF at the 10-day scale; however, temperature, relative humidity, and precipitation poorly explained variations in DSF. Similarly, multiple-factor analysis using a classification and regression tree revealed that maximum wind speed was a major influencing factor of dust storm occurrence at the 10-day scale, followed by relative humidity, evaporation, and solar radiation; temperature and precipitation had weak influences. These findings help clarify the mechanisms of dust storm occurrence in East Asia.

2.
BMC Neurol ; 19(1): 279, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31718589

RESUMO

BACKGROUND: Cerebral infarction occurs when the arteries to brain are obstructed, and motor impairment contralateral to responsible lesion is commonly recognized. Few studies have profiled the characteristics of cases with ipsilateral motor impairment. We sought to characterize clinical features of patients with motor dysfunction caused by ipsilateral ischemic stroke. METHODS: We retrieved and analyzed the medical data for patients with ipsilateral cerebral infarction. Patients were regarded as having ipsilateral cerebral infarction if motor impairment is ipsilateral to recent stroke lesions. RESULTS: Only 22 patients with unusual ipsilateral cerebral infarction were included in this study. Ipsilateral limb paralysis was observed in all cases, and one case showed central facioplegia. Majority of patients with limb paralysis (90.9%, 20/22) presented with mild muscle strength deficits (MRC grading of 4 or more). Most of the patients (72.7%, 16/22) had a past history of stroke, and previous strokes were contralateral to the side of the recent stroke in 14 out of 16 patients (87.5%). No history of stroke or cerebral injury was identified in seven patients. With aspect of MRI findings, recent infarct lesions of all cases were located along the corticospinal tract. CONCLUSIONS: History of stroke plays an important role in the pathogenesis of ipsilateral motor impairment, and cortical reorganization in the unaffected hemisphere may contribute to the compensation of motor function after stroke. Besides that, some cases with first stroke may be due to impairment of ipsilateral uncrossed corticospinal fibers.


Assuntos
Infarto Cerebral/complicações , Infarto Cerebral/patologia , Lateralidade Funcional/fisiologia , Paralisia/etiologia , Paralisia/fisiopatologia , Adulto , Idoso , Infarto Cerebral/diagnóstico por imagem , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos Motores/etiologia , Transtornos Motores/fisiopatologia , Neuroimagem , Paralisia/diagnóstico por imagem , Acidente Vascular Cerebral/complicações
3.
J Am Chem Soc ; 141(40): 15804-15817, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31553590

RESUMO

Cellular delivery of biomacromolecules is vital to medical research and therapeutic development. Cationic polymers are promising and affordable candidate vehicles for these precious payloads. However, the impact of polycation architecture and solution assembly on the biological mechanisms and efficacy of these vehicles has not been clearly defined. In this study, four polymers containing the same cationic poly(2-(dimethylamino)ethyl methacrylate) (D) block but placed in different architectures have been synthesized, characterized, and compared for cargo binding and biological performance. The D homopolymer and its diblock copolymer poly(ethylene glycol)-block-poly(2-(dimethylamino) ethyl methacrylate) (OD) readily encapsulate pDNA to form polyplexes. Two amphiphilic block polymer variants, poly(2-(dimethylamino)ethyl methacrylate)-block-poly(n-butyl methacrylate) (DB) and poly(ethylene glycol)-block-poly(2-(dimethylamino)ethyl methacrylate)-block-poly(n-butyl methacrylate) (ODB), self-assemble into micelles, which template pDNA winding around the cationic corona to form micelleplexes. Micelleplexes were found to have superior delivery efficiency compared to polyplexes and detailed physicochemical and biological characterizations were performed to pinpoint the mechanisms by testing hypotheses related to cellular internalization, intracellular trafficking, and pDNA unpackaging. For the first time, we find that the higher concentration of amines housed in micelleplexes stimulates both cellular internalization and potential endosomal escape, and the physical motif of pDNA winding into micelleplexes, reminiscent of DNA compaction by histones in chromatin, preserves the pDNA secondary structure in its native B form. This likely allows greater payload accessibility for protein expression with micelleplexes compared to polyplexes, which tightly condense pDNA and significantly distort its helicity. This work provides important guidance for the design of successful biomolecular delivery systems via optimizing the physicochemical properties.

4.
Acc Chem Res ; 52(5): 1347-1358, 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-30993967

RESUMO

The field of gene therapy, which aims to treat patients by modulating gene expression, has come to fruition and has landed several landmark FDA approvals. Most gene therapies currently rely on viral vectors to deliver nucleic acid cargo into cells, but there is significant interest in moving toward chemical-based methods, such as polymer-based vectors, due to their low cost, immunocompatibility, and tunability. The full potential of polymer-based delivery systems has yet to be realized, however, because most polymeric transfection reagents are either too inefficient or too toxic for use in the clinic. In this Account, we describe developments in carbohydrate-based cationic polymers, termed glycopolymers, for enhanced nonviral gene delivery. As ubiquitous components of biological systems, carbohydrates are a rich class of compounds that can be harnessed to improve the biocompatibility of non-native polymers, such as linear polyamines used for promoting transfection. Reineke et al. developed a new class of carbohydrate-based polymers called poly(glycoamidoamine)s (PGAAs) by step-growth polymerization of linear monosaccharides with linear ethyleneamines. These glycopolymers were shown to be both efficient and biocompatible transfection reagents. Systematic modifications of the structural components of the PGAA system revealed structure-activity relationships important to its function, including its ability to degrade in situ. Expanding upon the development of step-growth glycopolymers, monosaccharides, such as glucose, were functionalized as vinyl-based monomers for the formation of diblock copolymers via radical addition-fragmentation chain-transfer (RAFT) polymerization. Upon complexation with plasmid DNA, the glucose-containing block creates a hydrophilic shell that promotes colloidal stability as effectively as PEG functionalization. An N-acetyl-d-galactosamine variant of this diblock polymer yields colloidally stable particles that show increased receptor-mediated uptake by liver hepatocytes in vitro and promotes liver targeting in mice. Finally, the disaccharide trehalose was incorporated into polycationic structures using both step-growth and RAFT techniques. It was shown that these trehalose-based copolymers imparted increased colloidal stability and yielded plasmid and siRNA polyplexes that resist aggregation upon lyophilization and reconstitution in water. The aforementioned series of glycopolymers use carbohydrates to promote effective and safe delivery of nucleic acid cargo into a variety of human cells types by promoting vehicle degradation, tissue-targeting, colloidal stabilization, and stability toward lyophilization to extend shelf life. Work is currently underway to translate the use of glycopolymers for safe and efficient delivery of nucleic acid cargo for gene therapy and gene editing applications.

5.
Orthop Surg ; 11(2): 255-262, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31004410

RESUMO

OBJECTIVE: To compare the clinical efficacy of intramedullary nail fixation for intertrochanteric fractures assisted by orthopaedic robot navigation and the traditional intramedullary nail fixation in elderly patients, and to investigate the application advantages of intramedullary nail fixation for femoral intertrochanteric fractures assisted by orthopaedic robot navigation in the elderly. METHODS: Among the 51 patients with intertrochanteric fractures who were selected from April 2015 to September 2017 in the Affiliated Hospital of Chengdu University, 25 patients underwent the intramedullary nail fixation assisted by orthopaedic robot navigation (orthopaedic robot navigation surgery group) and 26 patients underwent the traditional intramedullary nail fixation (traditional surgery group). The operation time, the number of intraoperative fluoroscopy images taken, the frequency of guide pins inserted into the femoral marrow cavity, the amount of intraoperative bleeding, and the one-time success rate of the guide pin inserted into the femoral marrow cavity were recorded. Fracture healing and internal fixation were observed. The Harris score was used to evaluate hip joint function 1 year after surgery. RESULTS: All patients were followed up for 12-24 months. The operation time was 65.44 ± 8.01 min in the orthopaedic robot navigation surgery group and 77.50 ± 16.64 min in the traditional surgery group. The number of intraoperative fluoroscopy images taken was 10.28 ± 0.61 in the orthopaedic robot navigation surgery group and 13.23 ± 1.75 in the traditional surgery group. The frequency of guide pins inserted into the femoral marrow cavity was 1.00 ± 0.00 times in the orthopaedic robot navigation surgery group and 2.46 ± 1.10 times in the traditional surgery group. The one-time success rate of intramedullary pin puncture was 100% (25/25) in the orthopaedic surgical robot navigation surgery group and 19.23% (5/26) in the traditional surgery group. The amount of surgical bleeding was 90.80 ± 14.98 mL in the orthopaedic robot navigation surgery group and 118.46 ± 32.21 mL in the traditional surgery group. Compared with the traditional surgery group, the operation time of the orthopaedic surgical robot navigation surgery group was shorter (P < 0.05), the number of intraoperative fluoroscopy images taken was fewer (P < 0.05), the frequency of guide pins inserted into the femoral marrow cavity was lower (P < 0.05), the one-time success rate of intramedullary pin puncture was higher (P < 0.05), and the amount of surgical bleeding was less (P < 0.05). One year after surgery, fracture healing occurred in both groups without failure of internal fixation or fracture displacement. The Harris score of hip function in the orthopaedic robot navigation surgery group was 86.68 ± 6.23 and that in the traditional surgery group was 82.69 ± 6.85. It was higher than that in the traditional surgery group (P < 0.05). The fine rate of hip joint function in the orthopaedic robot navigation surgery group was 84.00% (21/25) and that in the traditional surgery group was 73.07% (19/26). There was no significant difference between the two groups (P > 0.05). CONCLUSION: Intramedullary nail fixation for intertrochanteric fractures assisted by orthopaedic robot navigation in elderly patients is an ideal method, offering a short operation time, minimal surgical trauma, less radiation, and good recovery of hip function.


Assuntos
Fixação Intramedular de Fraturas/métodos , Fraturas do Quadril/cirurgia , Procedimentos Cirúrgicos Robóticos/métodos , Idoso , Idoso de 80 Anos ou mais , Pinos Ortopédicos , Feminino , Fluoroscopia , Humanos , Masculino , Radiografia Intervencionista
6.
Epilepsy Behav ; 86: 163-165, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30037584

RESUMO

PURPOSE: Reflex epilepsy is a type of epilepsy with seizures that are consistently triggered by a specific stimulus. Zipai is a Chinese ancient card game which has been popular in Southern China for hundreds of years. We sought to report and characterize clinical features of patients with reflex epilepsy evoked by playing Zipai. METHODS: We collected and analyzed clinical data of patients with Zipai-induced epilepsy. Patients were regarded as having Zipai-induced epilepsy if they suffered at least two seizure attack during the course of playing Zipai. Prolonged electroencephalography (EEG) and brain magnetic resonance imaging (MRI) were applied to all patients. All patients were advised to avoid watching and playing Zipai games in daily life, instead of using antiepileptic drugs. The seizure outcome was assessed during outpatient visits and by telephone contact. RESULTS: Five patients were included in this study. No spontaneous seizures occurred in all five patients. No patients had experienced myoclonic and coexistent absences with generalized tonic-clonic seizures (GTCS). All patients had normal MRI and prolonged EEG findings. All patients were advised to avoid the Zipai game, and became seizure-free without medication during the follow-up period (mean 5.4 years, range 3.5-7 years). CONCLUSION: Zipai-induced epilepsy may be an unreported subtype form of reflex epilepsy with praxis induction. Nonpharmacological conservative treatment plays a significant role in the treatment of reflex epilepsy.


Assuntos
Aprendizagem da Esquiva , Epilepsia Reflexa/diagnóstico por imagem , Epilepsia Reflexa/prevenção & controle , Jogos Recreativos , Adulto , Anticonvulsivantes/uso terapêutico , Aprendizagem da Esquiva/fisiologia , China , Eletroencefalografia/tendências , Epilepsia Reflexa/psicologia , Seguimentos , Jogos Recreativos/psicologia , Humanos , Imagem por Ressonância Magnética/tendências , Masculino , Convulsões/diagnóstico por imagem , Convulsões/prevenção & controle , Convulsões/psicologia , Resultado do Tratamento , Adulto Jovem
7.
Science ; 360(6388): 518-521, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29724951

RESUMO

The emergence of Turing structures is of fundamental importance, and designing these structures and developing their applications have practical effects in chemistry and biology. We use a facile route based on interfacial polymerization to generate Turing-type polyamide membranes for water purification. Manipulation of shapes by control of reaction conditions enabled the creation of membranes with bubble or tube structures. These membranes exhibit excellent water-salt separation performance that surpasses the upper-bound line of traditional desalination membranes. Furthermore, we show the existence of high water permeability sites in the Turing structures, where water transport through the membranes is enhanced.


Assuntos
Membranas Artificiais , Nylons , Purificação da Água/métodos , Permeabilidade , Polimerização
8.
Nat Commun ; 9(1): 1507, 2018 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-29666367

RESUMO

The El Niño-Southern Oscillation (ENSO) can significantly affect the rapid intensification of tropical cyclones over the western North Pacific (WNP). However, ENSO events have various durations, which can lead to different atmospheric and oceanic conditions. Here we show that during short duration El Niño events, the WNP tropical cyclone rapid-intensification mean occurrence position migrates westward by ~8.0° longitude, which is caused by reduced vertical wind shear, increased mid-tropospheric humidity, and enhanced tropical cyclone heat potential over the westernmost WNP. The changes in these factors are caused by westward advected upper ocean heat during the decaying phase of a short duration El Niño. As super El Niño events tend to have short durations and their frequency is projected to increase under global warming, our findings have important implications for future projections of WNP tropical cyclone activity.

9.
Nat Commun ; 9(1): 747, 2018 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-29467472

RESUMO

Although effector CD4+ T cells readily respond to antigen outside the vasculature, how they respond to intravascular antigens is unknown. Here we show the process of intravascular antigen recognition using intravital multiphoton microscopy of glomeruli. CD4+ T cells undergo intravascular migration within uninflamed glomeruli. Similarly, while MHCII is not expressed by intrinsic glomerular cells, intravascular MHCII-expressing immune cells patrol glomerular capillaries, interacting with CD4+ T cells. Following intravascular deposition of antigen in glomeruli, effector CD4+ T-cell responses, including NFAT1 nuclear translocation and decreased migration, are consistent with antigen recognition. Of the MHCII+ immune cells adherent in glomerular capillaries, only monocytes are retained for prolonged durations. These cells can also induce T-cell proliferation in vitro. Moreover, monocyte depletion reduces CD4+ T-cell-dependent glomerular inflammation. These findings indicate that MHCII+ monocytes patrolling the glomerular microvasculature can present intravascular antigen to CD4+ T cells within glomerular capillaries, leading to antigen-dependent inflammation.


Assuntos
Apresentação do Antígeno , Linfócitos T CD4-Positivos/imunologia , Glomérulos Renais/irrigação sanguínea , Glomérulos Renais/imunologia , Monócitos/imunologia , Animais , Linfócitos B/imunologia , Linfócitos T CD4-Positivos/fisiologia , Capilares/imunologia , Adesão Celular , Movimento Celular , Glomerulonefrite/imunologia , Antígenos de Histocompatibilidade Classe II/metabolismo , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Fatores de Transcrição NFATC/metabolismo
10.
Bioconjug Chem ; 28(12): 2985-2997, 2017 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-29193962

RESUMO

A series of 3-guanidinopropyl methacrylamide (GPMA)-based polymeric gene delivery vehicles were developed via aqueous reversible addition-fragmentation chain transfer (RAFT) polymerization. The polymers have been evaluated for their cellular internalization ability, transfection efficiency, and cytotoxicity. Two homopolymers: P(GPMA20), P(GPMA34), were synthesized to study the effect of guanidium polymer length on delivery efficiency and toxicity. In addition, an N-acetyl-d-galactosamine (GalNAc)-based hydrophilic block was incorporated to produce diblock polymers, which provides a neutral hydrophilic block that sterically protects plasmid-polymer complexes (polyplexes) from colloidal aggregation and aids polyplex targeting to hepatocytes via binding to asialoglycoprotein receptors (ASGPRs). Polyplexes formed with P(GPMAx) (x = 20, 34) homopolymers were shown to be internalized via both energy-dependent and independent pathways, whereas polyplexes formed with block polymers were internalized through endocytosis. Notably, P(GPMAx) polyplexes enter cells very efficiently but are also very toxic to human hepatocellular carcinoma (HepG2) cells and triggered cell apoptosis. In comparison, the presence of a carbohydrate block in the polymer structures reduced the cytotoxicity of the polyplex formulations and increased gene delivery efficiency with HepG2 cells. Transfection efficiency and toxicity studies were also carried out with HEK 293T (human embryonic kidney) cells for comparison. Results showed that polyplexes formed with the P(GPMAx) homopolymers exhibit much higher transfection efficiency and lower toxicity with HEK 293T cells. The presence of the carbohydrate block did not further increase transfection efficiency in comparison to the homopolymers with HEK 293T cells, likely due to the lack of ASGPRs on the HEK 293T cell line. This study revealed that although guanidinium-based polymers have high membrane permeability, their application as plasmid delivery vehicles may be limited by their high cytotoxicity to certain cell types. Thus, the use of cell penetrating structures in polyplex formulations should be used with caution and carefully tailored toward individual cell/tissue types.


Assuntos
Acetilgalactosamina/química , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/patologia , Portadores de Fármacos/química , Guanidina/química , Neoplasias Hepáticas/patologia , Polímeros/química , Transporte Biológico , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/metabolismo , Portadores de Fármacos/toxicidade , Células Hep G2 , Humanos , Interações Hidrofóbicas e Hidrofílicas , Polimerização , Transfecção
11.
Oncotarget ; 8(55): 93444-93449, 2017 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-29212163

RESUMO

The identification of variables predictive of good seizure control following surgical tumor resection in adult glioma patients with tumor-related epilepsy would greatly benefit treatment decisions. Therefore, we analyzed the clinical data of adult patients with tumor-related epilepsy who underwent tumor resection at our institute between November 2011 and August 2013. Patients were divided into seizure-free (Engel Ia) and unfavorable outcome groups (Engel Ib-IV), and potential prognostic factors were analyzed. Of 90 patients, 61 (68%) had a favorable outcome at an average of 3 years after surgery. Our analyses indicated that younger age at surgery (P=0.048) and rare seizure frequency (P=0.006) were associated with significantly more favorable postoperative seizure-related outcomes. In conclusion, younger age at surgery and lesser seizure frequency were independent predictors of favorable epileptic seizure control after glioma resection in adults. Thus, early surgical resection is necessary for achieving favorable seizure outcome.

12.
J Neurol Sci ; 368: 132-7, 2016 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-27538616

RESUMO

PURPOSE: Cryptococcosis is a devastating opportunistic disease commonly encountered in organ transplant recipients and patients with acquired immunodeficiency syndrome (AIDS). Few studies have profiled the disease in immunocompetent patients. We sought to characterize the neuroimaging findings of cryptococcal meningitis among immunocompetent patients in China. MATERIALS AND METHODS: Retrospective review of all patients diagnosed with cryptococcal meningitis at our institute, on the basis of CSF culture or India Ink test, between November 2011 and February 2016, was performed. Only apparently immunocompetent patients, for whom at least one brain MRI examination was performed, were included in the analysis. The MRI results were available for all these patients before CSF diagnosis. Data related to variables such as patient demographics, clinical features, neuroimaging characteristics and CSF findings were analyzed. RESULTS: Eighteen apparently immunocompetent patients, for whom brain MRI radiographs were available, were included in the analysis. Abnormal MRI findings were observed in 16 patients. These included multiple intraparenchymal lesions with or without enhancement, prominent basal ganglia involvement, miliary distribution of parenchymal nodules, multiple dilated Virchow-Robin spaces and leptomeningeal enhancement. Six patients had ventriculomegaly. CONCLUSION: In our study, intraparenchymal findings were more common than leptomeningeal enhancement and perivascular lesions. Cryptococcal meningitis should be considered in the differential diagnosis of immunocompetent patients with brain MRI findings of prominent parenchymal involvement such as bilateral patchy lesions in basal ganglia or miliary distribution of parenchymal nodules.


Assuntos
Encéfalo/diagnóstico por imagem , Imagem por Ressonância Magnética , Meningite Criptocócica/diagnóstico por imagem , Adulto , Idoso , China , Feminino , Humanos , Imunocompetência , Masculino , Meningite Criptocócica/líquido cefalorraquidiano , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
13.
Philos Trans A Math Phys Eng Sci ; 374(2065): 20150197, 2016 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-26953173

RESUMO

In this big data era, it is more urgent than ever to solve two major issues: (i) fast data transmission methods that can facilitate access to data from non-local sources and (ii) fast and efficient data analysis methods that can reveal the key information from the available data for particular purposes. Although approaches in different fields to address these two questions may differ significantly, the common part must involve data compression techniques and a fast algorithm. This paper introduces the recently developed adaptive and spatio-temporally local analysis method, namely the fast multidimensional ensemble empirical mode decomposition (MEEMD), for the analysis of a large spatio-temporal dataset. The original MEEMD uses ensemble empirical mode decomposition to decompose time series at each spatial grid and then pieces together the temporal-spatial evolution of climate variability and change on naturally separated timescales, which is computationally expensive. By taking advantage of the high efficiency of the expression using principal component analysis/empirical orthogonal function analysis for spatio-temporally coherent data, we design a lossy compression method for climate data to facilitate its non-local transmission. We also explain the basic principles behind the fast MEEMD through decomposing principal components instead of original grid-wise time series to speed up computation of MEEMD. Using a typical climate dataset as an example, we demonstrate that our newly designed methods can (i) compress data with a compression rate of one to two orders; and (ii) speed-up the MEEMD algorithm by one to two orders.

14.
Photochem Photobiol Sci ; 14(9): 1722-8, 2015 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-26178816

RESUMO

Time-resolved spectra of a photoactive yellow protein (PYP) containing cyano-p-coumaric acid (CHCA) were recorded. To understand the mechanism of photo-isomerization, an electron-withdrawing CN group was introduced into the PYP to alter the C[double bond, length as m-dash]C double bond character. Free CHCA chromophores in aqueous solution underwent photo-isomerization whereas PYP with a bound CHCA (PYP-CN) exhibited no photocycle at acidic or alkaline pH or in urea and other solutions. Furthermore, no photocycle was observed with PYP mutants after illumination. This phenomenon cannot be fully explained by the electron-withdrawing properties of the CN group. We conclude that the CHCA chromophore in PYP was locked in the protein cage and that the CN group interacted with the protein residues.


Assuntos
Proteínas de Bactérias/química , Proteínas Luminescentes/química , Proteínas de Bactérias/genética , Ácidos Cumáricos/química , Elétrons , Escherichia coli , Concentração de Íons de Hidrogênio , Luz , Proteínas Luminescentes/genética , Estrutura Molecular , Mutação , Propionatos , Análise Espectral
15.
Zhongguo Zhong Yao Za Zhi ; 40(21): 4171-6, 2015 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-27071251

RESUMO

Through study on the correlation between atractylodis lactones ingredient content and climatic factors, we research regionalization from climatic of five main producing provinces of the country, in order to provide a scientific basis for atractylodis' conscious cultivation. By sampling from 40 origins which from five main producing provinces of the country, we use SPSS to analysis variation of atractylodis lactones ingredient content in different conditions of climatic factors and the effect of each factors. Then according to the relationship between atractylodis lactones ingredient content and climatic factors, we use ArcGIS to conduct ecological suitability regionalization based on climatic factors. The most suitable climatic condition for cultivation of atractylodis: the wettest month precipitation 220-230 mm, the warmest average temperature 25 degrees C, the average temperature of driest season 10 degrees C.


Assuntos
Atractylodes/crescimento & desenvolvimento , Atractylodes/química , China , Clima , Ecologia , Ecossistema , Estações do Ano , Temperatura
16.
Sci Rep ; 4: 4437, 2014 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-24658614

RESUMO

Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for "real world" application.

17.
Zhongguo Zhong Yao Za Zhi ; 39(23): 4566-70, 2014 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-25911802

RESUMO

Through study on the correlation between Atractylodis macrocephala lactones ingredient content and topographic factors, we researched regionalization from topography of five main producing provinces of the country, in order to provide a scientific basis for A. macrocephala reasonable cultivation. By sampling from 40 origins of five main producing provinces of the country, the variation of A. macrocephala lactones ingredient content in different conditions of topographic factors and the effect of altitude, slope and aspect was analyzed by SPSS. Then according to the relationship between A. macrocephala lactones ingredient content and topographic factors, the ecological suitability regionalization was conducted by using ArcGIS based on topographic factors. It is suitable for growth of A. macrocephala in the hilly and mountainous areas of southern whose A. macrocephala lactones ingredient content is in high levels. It is unsuitable for growth of A. macrocephala in Northern plain areas, but we can cultivate A. macrocephala in the hilly and mountainous areas of Northern. The most suitable topographic condition for cultivation of A. macrocephala : altitude 200 meters above, slope 3.00-4.99 degrees.


Assuntos
Atractylodes/crescimento & desenvolvimento , Ecossistema , Altitude , Atractylodes/química , China , Conservação dos Recursos Naturais , Medicamentos de Ervas Chinesas/análise
18.
AAPS PharmSciTech ; 10(3): 967-76, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19636711

RESUMO

The purpose of the present study was to investigate the permeation of glipizide (GP) and observe the effect of an interaction with amines as counter ions, including diethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, N-(2-hydroxylethyl) piperidine. Permeation experiments were performed in vitro, using rat abdominal skin as a barrier. The lipophilic donor system consisting of isopropyl myristate (IPM) and ethanol (EtOH; EI system, 8:2) produced a marked enhancement of GP flux through rat skin. All the amines investigated in this study had performed an enhancing effect on GP flux, and triethylamine had the most potent enhancing effect on GP in the vehicle IPM:EtOH = 8:2(w/w). In the presence of counter ions, the solubility of GP in the donor solution (IPM:EtOH = 8:2) was increased and the log K (o/w) of GP was decreased, which may due to higher solubility of the GP in the IPM:EtOH = 8:2(w/w). (13)C NMR spectroscopy was used to identify the ion-pairing formation between GP and the respective counter ion. It was surprising that all the four enhancers examined, such as isopropyl myristate, propylene glycol, N-methyl-2-pyrrolidone, azone, and oleic acid, had no enhancing effect on the percutaneous permeation of GP. This study showed that the formation of ion-pairs between GP and counter ions is a useful method to promote the skin permeation of GP.


Assuntos
Glipizida/farmacocinética , Hipoglicemiantes/farmacocinética , Absorção Cutânea/fisiologia , 1-Octanol/química , Algoritmos , Animais , Cromatografia Líquida de Alta Pressão , Cultura em Câmaras de Difusão , Excipientes , Glipizida/química , Hipoglicemiantes/química , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Masculino , Ratos , Ratos Wistar , Solubilidade , Solventes , Água/química
19.
Drug Dev Ind Pharm ; 35(6): 663-70, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19259875

RESUMO

PURPOSE: To investigate the influence of ion pairing and chemical enhancers on the transdermal delivery of meloxicam. METHOD: We examined the increased permeation of meloxicam produced by ion pair formation with six organic bases, diethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, and N-(2'-hydroxyethanol)-piperidine, and four normal permeation enhancers, oleic acid, menthol, azone, and N-methyl-2-pyrrolidone. The cumulative permeation was markedly increased in the presence of either a counter ion or chemical enhancers. In particular, we proved the formation of a meloxicam/amine ion-pair in solution by (13)C-NMR (nuclear magnetic resonance). RESULTS AND CONCLUSION: The cumulative permeation was markedly increased in the presence of either a counter ion or chemical enhancers. These results suggest that the degree of enhancement possibly depends on the structure and hydrophilicity of the counter ions.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Excipientes/química , Absorção Cutânea , Tiazinas/farmacocinética , Tiazóis/farmacocinética , Administração Cutânea , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Espectroscopia de Ressonância Magnética , Masculino , Meloxicam , Permeabilidade , Ratos , Ratos Wistar , Tiazinas/administração & dosagem , Tiazóis/administração & dosagem
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