RESUMO
BACKGROUND: In the fields of environmental monitoring and nuclear emergency, in order to obtain the relevant information of uranyl-induced environmental pollution and nuclear accident, it is necessary to establish a rapid quantitative analytical technique for uranyl ions. As a new promising technique, surface-enhanced Raman scattering (SERS) is hopeful to achieve this goal. However, uranyl ions are easily desorbed from SERS substrates under acidic conditions, and the structures of SERS substrates will be destroyed in the strong acidic aqueous solutions. Besides, the quantitative detection ability of SERS for uranyl ions needs to be promoted. Hence, it is necessary to develop new SERS substrates for accurate quantitative detection of trace uranyl in environmental water samples, especially in acidic solutions. RESULTS: In this work, we prepared silver ions/sodium alginate supramolecular hydrogel membrane (Ag+/SA SMH membrane), and the Ag+ ions from the membrane were transformed into Ag/Ag2O complex nanoparticles under laser irradiation. The Raman signal of uranyl was strongly enhanced under the synergistic interaction of electromagnetic enhancement derived from the Ag nanoparticles and charge transfer enhancement between uranyl and Ag2O. Utilizing the peak of SA (550 cm-1) as an internal standard, a quantitative detection with a LOD of 6.7 × 10-9 mol L-1 was achieved due to a good linear relation of uranyl concentrations from 1.0 × 10-8 mol L-1 to 2 × 10-6 mol L-1. Furthermore, foreign metal ions hardly affected the SERS detection of uranyl, and the substrate could determine trace uranyl in natural water samples. Particularly, the acidity had no obvious effect on SERS signals of uranyl ions. Therefore, in addition to the detection of uranyl ions in natural water samples, the proposed strategy could also detect uranyl ions in strong acidic solutions. SIGNIFICANCE AND NOVELTY: A simple one-step method was used to prepare an Ag+/SA SMH membrane for rapid quantitative detection of uranyl ions for the first time. The proposed substrate successfully detected uranyl ions under acidic conditions by immobilizing uranyl ion in hydrogel structure. In comparison with the previous studies, a more accurate quantitative analysis for uranyl ions was achieved by using an internal standard, and the proposed strategy could determine trace uranyl in either natural water samples or strong acidic solutions.
RESUMO
Objective: To systematically evaluate the efficacy and safety of repetitive transcranial magnetic stimulation (rTMS) on language function in patients with non-fluent aphasia post-stroke. Methods: We selected randomized clinical trials (RCT) that involved stroke patients with non-fluent aphasia, whose intervention was rTMS vs. no therapy or other therapy. Two researchers autonomously reviewed the literature based on the specified criteria for inclusion and exclusion and completed the process of data extraction, data verification, and quality evaluation. Meta-analysis was performed using RevMan 5.4 and Stata MP 17, while the assessment of risk of bias was carried out utilizing the Risk of Bias version 2 tool (RoB2). Results: The meta-analysis involved 47 RCTs, encompassing 2,190 patients overall. The indexes indicated that rTMS has the potential to decrease the severity of non-fluent aphasia in stroke patients, including improvement of the capability of repetition, naming, and spontaneous language. The determination of BDNF in the serum of patients was also increased. In addition, rTMS reduced the likelihood of depression in stroke patients. Conclusion: To summarize the relevant studies, rTMS has significant effects on improving the language abilities of stroke patients suffering from non-fluent aphasia, including the abilities of repetition, naming, and spontaneous language.
RESUMO
In light of the tremendous number of patients with vascular dementia in China, it is of great significance for the treatment of this disease to summarize related research focuses. In this study, articles on the treatment of vascular dementia, which were included in CNKI and Web of Science from January 1, 2012 to December 31, 2021, were analyzed. Specifically, CiteSpace 5.7.R2 was employed to visualize nationalities of authors, author affiliations, authors, keywords, and journals, and dissect the status quo and trend of research on the treatment of this disease. On this basis, the research focuses and evolution were elucidated. The findings are expected to serve as reference for the future research. Finally, 2 579 Chinese articles and 453 English articles were included. The annual number of published articles showed an upward trend. Authors from China published most papers and England had the highest centrality value. HU Yue-qiang and LIU Cun-zhi respectively published the most Chinese and English articles. Guangxi University of Chinese Medicine and Capital Medical University respectively topped the author affiliations in the number of published Chinese and English articles. Among the English journals, Anal Biochem and Stroke separately boasted the highest centrality value and the highest cited frequency. The analysis of keywords in the Chinese articles suggested that most studies on the treatment of vascular dementia focused on the observation of patients' mobility after treatment. Moreover, as for the therapeutic method, western medicine, as well as the Chinese medicine and acupuncture frequently attracted the attention of scholars. Basic research highlighted the oxidative stress, angiogenesis, and apoptosis. According to the analysis result of keywords in English articles on treatment of vascular dementia, the focus was the improvement of the memory function of patients with vascular dementia. As to the therapeutic method, drug therapy was frequently studied compared with other methods. The basic research focused on autophagy, nerve regeneration, and oxidative stress. This study concludes that the future research trend might be the combination of Chinese and western medicine in the treatment of vascular dementia.
Assuntos
Terapia por Acupuntura , Demência Vascular , Humanos , China , Demência Vascular/terapia , PublicaçõesRESUMO
Effective methods of detection and removal of iodide ions (I-) from radioactive wastewater are urgently needed and developing them remains a great challenge. In this work, an Ag+ decorated stable nano-MOF UiO-66-(COOH)2 was developed for the I- to simultaneously capture and sense in aqueous solution. Due to the uncoordinated carboxylate groups on the UiO-66-(COOH)2 framework, Ag+ was successfully incorporated into the MOF and enhanced the intrinsic fluorescence of MOF. After adding iodide ions, Ag+ would be produced, following the formation of AgI. As a result, Ag+@UiO-66-(COOH)2 can be utilized for the removal of I- in aqueous solution, even in the presence of other common ionic ions (NO2-, NO3-, F-, SO42-). The removal capacity as high as 235.5 mg/g was calculated by Langmuir model; moreover, the fluorescence of Ag+@UiO-66-(COOH)2 gradually decreases with the deposition of AgI, which can be quantitatively depicted by a linear equation. The limit of detection toward I- is calculated to be 0.58 ppm.
Assuntos
Poluentes Químicos da Água , Purificação da Água , Zircônio , Iodetos , Adsorção , Purificação da Água/métodos , ÁguaRESUMO
This work presents a rapid and highly sensitive colorimetric assay using bifunctional DNA probe decorated agarose microbeads (MBs) coupled with a cascade signal amplification system, including rolling circle amplification (RCA) and the hemin/G-quadruplex-catalyzed colorimetric reaction, for visualized detection of uranyl ions. The DNA probe integrates the UO22+-specific DNAzyme/substrate as the target recognition unit and a DNA primer as the signal conversion unit. The presence of uranyl ions induces the efficient cleavage of the DNA substrates with the catalysis of DNAzyme. Then the conjugated primers are released from MBs, initiating the RCA reaction (the first amplification). The RCA product consists of repetitive G-quadruplexes that can lead to a second amplification by catalyzing the oxidation of ABTS2- with hemin binding, resulting in a coloration that is visible to the naked eye. The whole assay procedure could be finished within 40 min, including recognition of uranyl and DNA cleavage (5 min), the RCA reaction (30 min) and data readout either by eye or using a UV-vis spectrometer (5 min for each sample). In the optimal conditions, concentrations as low as 5 nM uranyl ions could be distinguished by the naked eye. With UV-vis spectrometric measurement, the visible absorbance had a linear relationship with the concentration of uranyl ions with a dynamic range from 1 nM to 50 nM, and a low detection limit of 0.48 nM (i.e. â¼0.12 ppb) was obtained. Excellent selectivity and anti-interference capability in water samples were also certified. This facile visualized assay could be applied in detecting trace-level uranium for on-site environmental analysis.
Assuntos
Técnicas Biossensoriais , DNA Catalítico , Quadruplex G , Técnicas Biossensoriais/métodos , Colorimetria/métodos , Sondas de DNA , DNA Catalítico/química , Hemina/química , Íons , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/métodosRESUMO
BACKGROUND: Knee osteoarthritis (KOA) is a common joint disease worldwide, and the main cause of pain and disability in the elderly. Due to increased aging and rates of obesity of the global population, the number of patients with KOA is expected to increase. To reduce the burden of KOA, effective and safe interventions should be developed to reduce pain and improve range of motion, functionality, and quality of life. The aim of the proposed randomized controlled study was to evaluate the efficacy and safety of a traditional Chinese medicine (TCM) rehabilitation therapy in the treatment of KOA. METHODS: This multicenter, randomized, double-blind, parallel group, placebo-controlled trial will include a total of 200 patients with KOA. The enrolled patients will be randomly divided into the experimental group (n=100) and control group (n=100). The experimental group will receive basic treatment plus TCM rehabilitation therapy, while the control group will receive basic treatment plus physiotherapy regimen. Primary endpoints will include clinical efficacy outcomes, visual analog scale, Western Ontario and McMaster Universities Osteoarthritis Index score, and Knee Outcome Survey Activities of Daily Living Scale score. The data will help determine whether TCM rehabilitation therapy is beneficial for the treatment of KOA. DISCUSSION: The results will provide high-quality guidance for the current clinical treatment of KOA, and provide patients with more options for symptom relief. The findings from this study may provide updated evidence concerning the efficacy and safety of TCM for patients with KOA.
Assuntos
Osteoartrite do Joelho , Atividades Cotidianas , Idoso , Humanos , Medicina Tradicional Chinesa , Estudos Multicêntricos como Assunto , Medição da Dor , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do TratamentoRESUMO
OBJECTIVE: The purpose of this study was to review the effects of robot-assisted therapy (RT) for improving poststroke upper extremity motor impairment. METHODS: The PubMed, Embase, Medline, and Web of Science databases were searched from inception to April 8, 2020. Randomized controlled trials that were conducted to evaluate the effects of RT on upper extremity motor impairment poststroke and that used Fugl-Meyer assessment for upper extremity scores as an outcome were included. Two authors independently screened articles, extracted data, and assessed the methodological quality of the included studies using the Physiotherapy Evidence Database (PEDro) scale. A random-effects meta-analysis was performed to pool the effect sizes across the studies. RESULTS: Forty-one randomized controlled trials with 1916 stroke patients were included. Compared with dose-matched conventional rehabilitation, RT significantly improved the Fugl-Meyer assessment for upper extremity scores of the patients with stroke, with a small effect size (Hedges g = 0.25; 95% CI, 0.11-0.38; I2 = 45.9%). The subgroup analysis revealed that the effects of unilateral RT, but not that of bilateral RT, were superior to conventional rehabilitation (Hedges g = 0.32; 95% CI, 0.15-0.50; I2 = 55.9%). Regarding the type of robot devices, the effects of the end effector device (Hedges g = 0.22; 95% CI, 0.09-0.36; I2 = 35.4%), but not the exoskeleton device, were superior to conventional rehabilitation. Regarding the stroke stage, the between-group difference (ie, RT vs convention rehabilitation) was significant only for people with late subacute or chronic stroke (Hedges g = 0.33; 95% CI, 0.16-0.50; I2 = 34.2%). CONCLUSION: RT might be superior to conventional rehabilitation in improving upper extremity motor impairment in people after stroke with notable upper extremity hemiplegia and limited potential for spontaneous recovery.
Assuntos
Exoesqueleto Energizado , Robótica/métodos , Reabilitação do Acidente Vascular Cerebral/métodos , Extremidade Superior/fisiopatologia , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Recuperação de Função FisiológicaRESUMO
In this article, a novel method to synthesize graphene quantum dots was developed via thermal treatment of crude graphite oxide (GO) in a dry and alkaline condition to cut the crude GO sheets into small graphene quantum dots (named as aGQDs). The aGQDs are nano-scale reduced graphene oxide pieces with the sizes around 5-10 nm. The aGQDs could disperse in water for their richment of oxygen-containing groups. The fluorescence properties were carefully investigated. The aGQDS aqueous solution shows a bright yellow-green fluorescence under the UV illumination. Besides, the uranyl ions show a strong fluorescence quenching effect on the a aGQD aqueous solution even at a low concentration (~10-7 M) compared with other common ions in natural water-body, which makes that these aGQDs could be applied as a chemosensor for detection of uranyl ions with good sensitivity and selectivity.
RESUMO
In this study, a novel signal-increase electrochemiluminescence (ECL) biosensor has been developed for the detection of glucose based on graphene quantum dot/glucose oxidase (GQD/GOx) on Ti foil. The proposed GQD with excellent ECL ability is synthesized through a green one-step strategy by the electrochemical reduction of graphene oxide quantum dot. Upon the addition of glucose, GOx can catalytically oxidize glucose and the direct electron transfer between the redox centre of GOx and the modified electrode also has been realized, which results in the bio-generated H2O2 for ECL signal increase in GQD and realizes the direct ECL detection of glucose. The signal-increase ECL biosensor enables glucose detection with high sensitivity reaching 5 × 10-6 mol l-1 in a wide linear range from 5 × 10-6 to 1.5 × 10-3 mol l-1. Additionally, the fabrication process of such GQD-based ECL biosensor is also suitable to other biologically produced H2O2 system, suggesting the possible applications in the sensitive detection of other biologically important targets (e.g. small molecules, protein, DNA and so on).
RESUMO
Efficient and sustainable remediation technologies for uranium have recently been gaining more and more interest. Adsorption techniques are facile, effective and universal for kinds of heavy metal ions. In this paper, sandwich-like Mn3O4@reduced graphene oxide (Mn3O4@G) nano-composites were prepared facilely and greenly by adding NaOH solution into crude graphite oxide suspension prepared via the Hummers' method to modify the pH. The Mn3O4@G nanocomposites possess a reasonable maximum equilibrium adsorption quantity 195.6 mg [U] g-1. Moreover, the magnetism of Mn3O4@G makes it easy to remove Mn3O4@G from water by strong magnet field.
RESUMO
Charge-transfer (CT) is an important enhancement mechanism in the field of surface-enhanced Raman scattering (SERS) that typically increases the Raman intensity of molecules by as much as 10-100 times. Herein, a low-cost Ag2O aggregates substrate was prepared via a facile chemical precipitation method, and the calculated CT-based enhancement factor of the uranyl ions adsorbed on it reached as high as 105, a metal-comparable value. The efficient photoinduced CT process from the valence band of Ag2O to the LUMO of uranyl ions under appropriate excitation sources resulted in the repulsion of the axial oxygen atoms of the OUO bond, which enhanced its polarizability, creating a more intense Raman mode. To the best of our knowledge, this study firstly reports such a strong photoinduced CT enhancement of uranyl ions, with concentrations of 10-8 mol L-1 or lower being detected using this Ag2O substrate. Most importantly, this research has shown that the photoinduced CT enhancement also contributes to the SERS of uranyl ions on pure Ag substrates which have often been ascribed to the electromagnetic enhancement in previous studies. In addition, Ag2O can be used to selectively detect uranyl ions without interference from many other molecules or ions because of the energy matching rule of the photoinduced CT process, which was readily available for uranyl detection in the environmental aqueous solution.
RESUMO
BACKGROUND: The Quality of Life in Neurological Disorders (Neuro-QoL) item banks evaluate and monitor the physical, mental, and social health of individuals with neurological conditions. Neuro-QoL items can be administered via short form or computerized adaptive testing. This paper describes the English-to-Simplified Chinese translation of 299 items from 13 adult item banks, which are publicly available. METHODS: Items were translated according to the Functional Assessment of Chronic Illness Therapy (FACIT) method, including forward and backward translation, reconciliation, expert reviews, and cognitive debriefing with both general and clinical populations in China. RESULTS: Most of the 299 Simplified Chinese items were well understood by the respondents. Revisions were made on a small number of items after cognitive debriefing. Although some difficulties were encountered in the translation process, all 13 item banks were linguistically validated with acceptable translations. CONCLUSION: All Chinese adult Neuro-QoL measures are linguistically equivalent to their English sources. Future work includes psychometric validation of these measures in order to create a final version of the item banks. The translation methodology used in this study can serve as a blueprint for researchers in other countries interested in translating the Neuro-QoL.
Assuntos
Doenças do Sistema Nervoso/psicologia , Qualidade de Vida/psicologia , Traduções , Adulto , China/etnologia , Doença Crônica , Compreensão , Humanos , Linguística , Psicometria , Inquéritos e Questionários , TraduçãoRESUMO
BACKGROUND: Oxford Cognitive Screen is designed for assessing cognitive functions of poststroke patients. This study was aimed to assess the psychometric properties of the Chinese (Putonghua) version of the Oxford Cognitive Screen-Putonghua (OCS-P) for use among poststroke patients without neglect. METHODS: Expert review panel evaluated content validity of the Chinese-translated items. After pilot tested the translated items, the patients and healthy participants completed the OCS-P as well as the Montreal Cognitive Assessment (MoCA-ChiB) and Goldenberg's test. A group of patients completed OCS-P for the second time within seven days. Data analyses included confirmatory factor analysis, item difficulty and item-total correlation, inter- and intrarater reliability, internal consistency, and between-group discrimination. RESULTS: One hundred patients and 120 younger (n = 60) or older (n = 60) healthy participants completed all the tests. Modifications were required for items in the "Picture Naming", "Orientation", and "Sentence Reading" subscales. Confirmatory factor analysis revealed a three-factor structure for the OCS-P subscales. The internal consistency coefficients for the three identified test dimensions were 0.30 to 0.52 (Cronbach's alpha). Construct validity coefficients between the OCS-P and MoCA-ChiB subscales were 0.45 < r < 0.79 (p < 0.001) and the "Praxis" subscale of OCS-P and Goldenberg's test was r = 0.72 (p < 0.001). The interrater reliability coefficients for the subscales were in general higher than the intrarater reliability coefficients. The "Picture Naming" and "Numerical Cognition" subscales were the most significant (p = 0.003) for differentiating patient participants from their older healthy counterpart. CONCLUSION: This study generated satisfactory evidence on the content validity, substantive validity, construct validity, inter- and intrarater reliability, and known-group discrimination of the OCS-P. They support its application among poststroke patients who speak Putonghua. Future studies could review the existing five-dimension domains for improving its structural validity and internal consistency as well as generate evidence of the OCS-P for use among the poststroke patients with neglect.
Assuntos
Transtornos Cognitivos/diagnóstico , Psicometria , Adulto , China , Cognição , Transtornos Cognitivos/etiologia , Humanos , Masculino , Reprodutibilidade dos Testes , Acidente Vascular Cerebral , Inquéritos e QuestionáriosRESUMO
BACKGROUND Previous studies suggested that inhibition of apoptosis prevents the dysfunction of ischemia-reperfusion injury. In the pathogenesis of ischemia-reperfusion injury, JNK/ERK1/2 and p38 play an essential role in regulation of cell apoptosis. Electroacupuncture (EA), a form of acupuncture, has demonstrated superiority in preventing ischemia-reperfusion injury, but the underlying mechanism is unclear. In the present study, we explored the effects of electroacupuncture at Shenting (GV24) and Baihui (GV20) acupoints on focal cerebral ischemia-reperfusion (MCAO) rats, and explored whether JNK/ERK1/2- and p38-mediated cell apoptosis are involved. MATERIAL AND METHODS The rats were divided into a sham operation control group, an ischemia group, and an electroacupuncture group with acupuncture applied for 10 days (30 min per day). TTC staining was used to calculate the ischemic brain volume. TUNEL staining and transmission electron microscopy were used to detect cell apoptosis. Western blot analysis and Bio-Plex were used to detect JNK, p38, ERK1/2, Bcl-2, and Bax protein expression. RESULTS We found that electroacupuncture at day 10 significantly reduced cerebral infarction. In addition, electroacupuncture suppressed activation of JNK and p38, while enhancing the activation of ERK1/2 in the peri-ischemic regions. Consequently, the effect of electroacupuncture on these pathways resulted in the inhibition of apoptosis, which was demonstrated by TUNEL and transmission electron microscopy. We found that electroacupuncture upregulated the anti-apoptotic Bcl-2/Bax ratio in peri-ischemic regions. CONCLUSIONS Our findings suggest that inhibition of cell apoptosis via regulating multiple signaling pathways might be a mechanism whereby electroacupuncture has a positive therapeutic effect on post-stroke impairment.
Assuntos
Apoptose , Isquemia Encefálica/terapia , Eletroacupuntura , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Traumatismo por Reperfusão/enzimologia , Traumatismo por Reperfusão/terapia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Pontos de Acupuntura , Animais , Isquemia Encefálica/complicações , Isquemia Encefálica/enzimologia , Isquemia Encefálica/patologia , Infarto Cerebral/patologia , Infarto Cerebral/terapia , Infarto da Artéria Cerebral Média/complicações , Infarto da Artéria Cerebral Média/patologia , Masculino , Biossíntese de Proteínas , Ratos Sprague-Dawley , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/patologia , Proteína X Associada a bcl-2/metabolismoRESUMO
BACKGROUND: Upper limb dysfunction is common after stroke, posing an important challenge for post-stroke rehabilitation. The clinical efficacy of acupuncture for the recovery of post-stroke upper limb function has been previously demonstrated. Mirror therapy (MT) has also been found to be effective. However, the effects of acupuncture and MT have not been systematically compared. This trial aims to elucidate the synergistic effects of acupuncture and MT on upper limb dysfunction after stroke. METHODS: A 2 × 2 factorial randomized controlled trial will be conducted at the rehabilitation hospitals affiliated with Fujian University of Traditional Chinese Medicine. A total of 136 eligible subjects will be randomly divided into acupuncture treatment (AT), MT, combined treatment, and control groups in a 1:1:1:1 ratio. All subjects will receive conventional treatment. The interventions will be performed 5 days per week for 4 weeks. AT, MT, and combined treatment will be performed for 30 min per day (combined treatment: AT 15 min + MT 15 min). The primary outcomes in this study will be the mean change in scores on both the FMA and WMFT from baseline to 4 weeks intervention and at 12 weeks follow-up between the two groups and within groups. The secondary outcomes are the mean change in the scores on the Visual Analogue Scale, Stroke Impact Scale, and modified Barthel index. Medical abstraction of adverse events will be assessed at each visit. DISCUSSION: The results of this trial will demonstrate the synergistic effect of acupuncture and MT on upper limb motor dysfunction after stroke. In addition, whether AT and MT, either combined or alone, are more effective than the conventional treatment in the management of post-stroke upper limb dysfunction will also be determined. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR-IOR-17011118 . Registered on April 11, 2017. Version number: 01.2016.09.1.
Assuntos
Terapia por Acupuntura , Terapia por Exercício/métodos , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/terapia , Extremidade Superior/inervação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Terapia Combinada , Avaliação da Deficiência , Feminino , Lateralidade Funcional , Humanos , Comportamento Imitativo , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados Aleatórios como Assunto , Recuperação de Função Fisiológica , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/fisiopatologia , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
Persistent organic pollutants (POPs) are key pollutants due to their persistence, refractory biodegradation, high toxicity and bioaccumulation in the food chain. This review (with 93 refs.) covers the progress made in the past decades in the application of carbonaceous materials for electrochemical detection of POPs as listed in the Stockholm Convention. Following an introduction into the field, typical carbonaceous materials for use in electrodes are discussed, with subsection on carbon nanotubes, graphene, reduced graphene oxide, graphitic carbon nitride and carbon dots. This is followed by a section on application of carbonaceous materials in electrochemical detection, with subsections on the use of carbon nanotubes, of (doped-) graphene, of reduced graphene oxide, of graphitic carbon nitride, and of carbon dots. The review concludes with conclusions and future perspectives. The detection mechanisms of POPs are also discussed. Graphical abstract Advanced carbonaceous materials for the electrochemical determination of persistent organic pollutants.
RESUMO
This study visualized and analyzed the developing trends and hot topics in natural disaster research. 19694 natural disaster-related articles (January 1900 to June 2015) are indexed in the Web of Science database. The first step in this study is using complex networks to visualize and analyze these articles. CiteSpace and Gephi were employed to generate a countries collaboration network and a disciplines collaboration network, and then attached hot topics to countries and disciplines, respectively. The results show that USA, China, and Italy are the three major contributors to natural disaster research. "Prediction model", "social vulnerability", and "landslide inventory map" are three hot topics in recent years. They have attracted attention not only from large countries like China but also from small countries like Panama and Turkey. Comparing two hybrid networks provides details of natural disaster research. Scientists from USA and China use image data to research earthquakes. Indonesia and Germany collaboratively study tsunamis in the Indian Ocean. However, Indonesian studies focus on modeling and simulations, while German research focuses on early warning technology. This study also introduces an activity index (AI) and an attractive index (AAI) to generate time evolution trajectories of some major countries from 2000 to 2013 and evaluate their trends and performance. Four patterns of evolution are visible during this 14-year period. China and India show steadily rising contributions and impacts, USA and England show relatively decreasing research efforts and impacts, Japan and Australia show fluctuating activities and stable attraction, and Spain and Germany show fluctuating activities and increasing impacts.
Assuntos
Desastres , Bibliometria , Pesquisa Biomédica/tendências , China , Humanos , Cooperação Internacional , Itália , Estados UnidosRESUMO
Uranium alloys containing a low concentration of titanium have received wide attention due to their greatly enhanced corrosion resistance and outstanding mechanical performances. Herein, we investigated the effect of macroscopic defects on the corrosion behavior of U-0.79 wt%Ti (denoted as U-Ti) alloy in 0.01 M NaCl solution using traditional electrochemical testing technologies and a novel scanning electrochemical composite probe (SECP). The results demonstrate that pitting corrosion occurs rapidly on the alloy surface due to macroscopic defects. Moreover, macroscopic defects led to a decrease in corrosion potential and polarization resistance, and an increase in corrosion current density. Furthermore, the potential and pH value distributions were detected in the same region using the composite probe. The results show that the region around the macroscopic defects become corrosion-active positions and the potential difference (vs. the average potential of the alloy surface) in this area is significantly higher than that at positions without macroscopic defects, while the opposite was observed for the pH value distribution. In addition, the distribution of the vertical direction (Z) potential at the active point was clearly different from that at the inactive point. A possible reason for this could lie in the difference in the electric field distribution and electrode reaction type between the active point and inactive point on the alloy surface.
RESUMO
Post-stroke memory dysfunction (PMD) is one of the most common forms of cognitive impairment among stroke survivors. However, only a limited number of studies have directly investigated the neural mechanisms associated with memory decline. The aim of the present study was to identify dynamic changes in the functional organization of the default mode network (DMN) and the dorsal attention network of patients with PMD. A total of 27 patients with PMD who experienced a stroke in the right hemisphere were enrolled in the current study, along with 27 healthy control subjects matched by age, sex, and educational level. A behavioral examination and functional magnetic resonance imaging scan were performed. The data were analyzed using an independent component analysis method. The results revealed a significantly increased functional connectivity between the DMN and prefrontal cortex (left middle/inferior frontal and left precentral gyri), temporal regions (left superior temporal gyrus), and bilateral and posterior cingulate gyri/precuneus (P<0.001). There was also a significantly decreased functional connectivity between the DMN and right middle temporal gyrus, left uvula, and right inferior parietal lobule, and between the dorsal attention network and prefrontal cortex (left precentral/inferior and right inferior/middle frontal gyri), right inferior parietal gyrus, and right insula (P<0.001). These results suggest that the stroke affected both the lesioned and contralesional hemispheres. The prefrontal cortex, temporal regions, insula, and posterior cingulate gyrus/precuneus serve a crucial role in memory processing.
RESUMO
A previous study by our group found that electro-acupuncture (EA) at the Shenting (DU24) and Baihui (DU20) acupoints ameliorates cognitive impairment in rats with cerebral ischemia-reperfusion (I/R) injury. However, the precise mechanism of action has remained largely unknown. The present study investigated whether brain-derived neurotropic factor (BDNF) mediates hippocampal synaptic plasticity as the underlying mechanism. Rats were randomly divided into three groups: The sham operation control (Sham) group, the focal cerebral ischemia-reperfusion (I/R) group, and the I/R with EA treatment (I/R+EA) group. The I/R+EA group received EA treatment at the Shenting (DU24) and Baihui (DU20) acupoints after the operation. EA treatment was found to ameliorate neurological deficits (P<0.05) and reduce the cerebral infarct volume (P<0.01). In addition, EA improved cognitive function in cerebral I/R-injured rats (P<0.05). Furthermore, EA treatment promoted synaptic plasticity. Simultaneously, EA increased the hippocampal expression of BDNF, its high-affinity tropomyosin receptor kinase B (TrkB) and post-synaptic density protein-95 (PSD-95) in the rats with cerebral I/R injury. Collectively, the findings suggested that BDNF-mediated hippocampal synaptic plasticity may be one mechanism via which EA treatment at the Shenting (DU24) and Baihui (DU20) acupoints improves cognitive function in cerebral I/R injured rats.