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1.
Medicine (Baltimore) ; 103(28): e38919, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38996140

RESUMO

RATIONALE: Rectal cavernous hemangioma is a rare, benign vascular disease that seldom causes lower gastrointestinal bleeding, characterized by a high rate of misdiagnosis and missed diagnoses. Surgical treatment is considered to be relatively effective; however, it is accompanied by certain employed in the treatment of superficial hemangioma, boasting the advantages of minimally invasive surgery, including safety, effectiveness, reduced trauma, and rapid recovery. However, there is a lack of literature regarding the application of foam sclerosing agents for gastrointestinal hemangiomas. CASE CONCERNS: We present a case of a 60-year-old male who was admitted to our hospital with a history of recurrent hematochezia for >1 year and worsening symptoms for 1 week. The patient's medical history was unremarkable. DIAGNOSES: Following colonoscopy, nuclear magnetic resonance imaging, computed tomography, and other examinations, the final diagnosis was rectal cavernous hemangioma. INTERVENTIONS: Due to the patient's refusal of surgery, endoscopic foam sclerotherapy using a lauromacrogol injection was performed after obtaining informed consent from the patient and their relatives. OUTCOMES: Post-sclerotherapy, hematochezia symptoms ceased, and no adverse reactions were observed. Two months later, colonoscopy and nuclear magnetic resonance imaging showed that the hemangioma had almost completely disappeared, with only a small amount of tumor remnants, yielding a satisfactory curative effect. CONCLUSION: Our findings indicate that endoscopic injection of a lauromacrogol foam sclerosing agent is a safe, effective, and minimally invasive treatment option for gastrointestinal cavernous hemangiomas.


Assuntos
Colonoscopia , Hemangioma Cavernoso , Neoplasias Retais , Soluções Esclerosantes , Escleroterapia , Humanos , Masculino , Pessoa de Meia-Idade , Hemangioma Cavernoso/terapia , Hemangioma Cavernoso/diagnóstico por imagem , Escleroterapia/métodos , Soluções Esclerosantes/uso terapêutico , Soluções Esclerosantes/administração & dosagem , Neoplasias Retais/terapia , Colonoscopia/métodos , Polidocanol/uso terapêutico , Polidocanol/administração & dosagem , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/terapia
2.
China CDC Wkly ; 6(26): 619-623, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38966310

RESUMO

What is already known about this topic?: Since May 2022, a global outbreak of mpox has emerged in more than 100 non-endemic countries. As of December 2023, over 90,000 cases had been reported. The outbreak has predominantly affected men who have sex with men (MSM), with sexual contact identified as the principal mode of transmission. What is added by this report?: Since June 2023, China has faced an occurrence of mpox, predominantly affecting the MSM population. Approximately 90% of those affected reported engaging in homosexual behavior within 21 days prior to symptom onset, a trend that aligns with the global outbreak pattern. The prompt identification of cases, diligent tracing of close contacts, and the implementation of appropriate management strategies have successfully mitigated the spread of mpox virus in China. What are the implications for public health practice?: We propose that mpox is transmitted locally within China. Drawing from our experiences in controlling the virus spread, it is crucial to investigate and formulate effective surveillance and educational strategies. Importantly, we must encourage high-risk populations to promptly seek medical care upon the onset of symptoms.

3.
IUBMB Life ; 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39046102

RESUMO

The utilization of anti-CD3/CD28 magnetic beads for T cell expansion in vitro has been investigated for adoptive cell transfer therapy. However, the impact of the CD3/CD28 antibody ratio on T cell differentiation and function remains incompletely elucidated. This study seeks to address this knowledge gap. To begin with, CD3 antibodies with a relatively low avidity for Jurkat cells (Kd = 13.55 nM) and CD28 antibodies with a relatively high avidity (Kd = 5.79 nM) were prepared. Afterwards, anti-CD3/CD28 antibodies with different mass ratios were attached to magnetic beads to examine the impacts of different antibody ratios on T cell capture, and proliferation. The research demonstrated that the most significant expansion of T cells was stimulated by the anti-CD3/CD28 magnetic beads with a mass ratio of 2:1 for CD3 antibodies and CD28 antibodies. Moreover, CD25 and PD1 expression of expanded T cells increased and then decreased, with lower CD25 and PD1 expression in the later stages of expansion indicating that T cells were not depleted. These T cells, which are massively expanded in vitro and have excellent expansion potential, can be infused back into the patient to treat tumor patients. This study shows that altering the ratio of anti-CD3/CD28 antibodies can control the strength of T cell stimulation, thereby leading to the improvement of T cell activation. This discovery can be utilized as a guide for the creation of other T cell stimulation approaches, which is beneficial for the further development of tumor immunotherapy technology.

4.
J Chromatogr A ; 1724: 464929, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38669942

RESUMO

When purifying mAb from serum-containing hybridoma culture supernatant, it is essential that mouse IgG remains free from contaminations of bovine IgG. However, the broadly used Protein A resin cannot achieve this goal due to binding between both mouse and bovine IgG. Here, a novel nanobody-based affinity purification magnetic beads that discriminates mouse IgG from bovine IgG was developed. To bind all subtypes of mouse IgG (IgG1, IgG2a, IgG2b and IgG3) that contain the kappa light chain, mCK (mouse kappa constant region)-specific nanobody binders were selected from an immune phage display VHH library; this library was constructed with peripheral blood mononuclear cells (PBMCs), which were collected from Bactrian camels immunized with a mix of intact mouse IgGs (IgG1, IgG2a, IgG2b and IgG3). A novel clone that exhibited a higher expression level and a higher binding affinity was selected (4E6). Then, the 4E6 nanobody in the format of VHH-hFC (human Fc) was conjugated on magnetic beads with a maximal binding capacity of 15.41±0.69 mg mouse IgG/mL beads. Furthermore, no bovine IgG could be copurified from hybridoma culture supernatant with immunomagnetic beads. This approach is valuable for the large-scale in vitro production of highly pure antibodies by hybridoma cells.


Assuntos
Anticorpos Monoclonais , Animais , Bovinos , Humanos , Camundongos , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/isolamento & purificação , Camelus , Cromatografia de Afinidade/métodos , Hibridomas , Regiões Constantes de Imunoglobulina/química , Imunoglobulina G/isolamento & purificação , Imunoglobulina G/imunologia , Cadeias kappa de Imunoglobulina/imunologia , Cadeias kappa de Imunoglobulina/química , Biblioteca de Peptídeos , Anticorpos de Domínio Único/imunologia , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/isolamento & purificação
5.
Environ Sci Pollut Res Int ; 31(13): 19257-19273, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38355864

RESUMO

Since the beginning of the twenty-first century, the rapid development of modern technologies has brought unprecedented social prosperity to mankind as technologies penetrate every sector of the economy. These technologies have given a new dimension to the energy sector. The key purpose of this study is to investigate the crucial impact of technological revolutions, namely, smart grids, smart devices, financial innovations, and environmental innovations, on greenhouse gas emissions (GHGs). To this end, the study utilized data from European, Asian, Middle Eastern, and African countries and employed first- and second-generation methods, such as DOLS, FMOLS, and CS-ARDL models. The research shows that smart grids are the only factor in reducing GHGs, regardless of geographic division. Hence, linking smart grid resources to climate change goals requires short-term deployment strategies with a clear long-term vision and the fundamental goal of transforming the power structure into a net zero-emission system. The study also demonstrates that the emergence of ICT in electricity consumption has not yet reached a level that can promote environmental excellence. The study documented the critical role of financial innovation and environmental innovation in addressing environmental degradation.


Assuntos
Carbono , Gases de Efeito Estufa , Desenvolvimento Econômico , Tecnologia , Mudança Climática , Dióxido de Carbono/análise , Energia Renovável
6.
World J Gastroenterol ; 30(5): 440-449, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38414583

RESUMO

BACKGROUND: According to practice guidelines, endoscopic band ligation (EBL) and endoscopic tissue adhesive injection (TAI) are recommended for treating bleeding from esophagogastric varices. However, EBL and TAI are known to cause serious complications, such as hemorrhage from dislodged ligature rings caused by EBL and hemorrhage from operation-related ulcers resulting from TAI. However, the optimal therapy for mild to moderate type 1 gastric variceal hemorrhage (GOV1) has not been determined. Therefore, the aim of this study was to discover an individualized treatment for mild to moderate GOV1. AIM: To compare the efficacy, safety and costs of EBL and TAI for the treatment of mild and moderate GOV1. METHODS: A clinical analysis of the data retrieved from patients with mild or moderate GOV1 gastric varices who were treated under endoscopy was also conducted. Patients were allocated to an EBL group or an endoscopic TAI group. The differences in the incidence of varicose relief, operative time, operation success rate, mortality rate within 6 wk, rebleeding rate, 6-wk operation-related ulcer healing rate, complication rate and average operation cost were compared between the two groups of patients. RESULTS: The total effective rate of the two treatments was similar, but the efficacy of EBL (66.7%) was markedly better than that of TAI (39.2%) (P < 0.05). The operation success rate in both groups was 100%, and the 6-wk mortality rate in both groups was 0%. The average operative time (26 min) in the EBL group was significantly shorter than that in the TAI group (46 min) (P < 0.01). The rate of delayed postoperative rebleeding in the EBL group was significantly lower than that in the TAI group (11.8% vs 45.1%) (P < 0.01). At 6 wk after the operation, the healing rate of operation-related ulcers in the EBL group was 80.4%, which was significantly greater than that in the TAI group (35.3%) (P < 0.01). The incidence of postoperative complications in the two groups was similar. The average cost and other related economic factors were greater for the EBL than for the TAI (P < 0.01). CONCLUSION: For mild to moderate GOV1, patients with EBL had a greater one-time varix eradication rate, a greater 6-wk operation-related ulcer healing rate, a lower delayed rebleeding rate and a lower cost than patients with TAI.


Assuntos
Varizes Esofágicas e Gástricas , Adesivos Teciduais , Humanos , Varizes Esofágicas e Gástricas/complicações , Varizes Esofágicas e Gástricas/cirurgia , Úlcera/complicações , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/cirurgia , Ligadura/efeitos adversos , Ligadura/métodos , Endoscopia Gastrointestinal/efeitos adversos , Endoscopia Gastrointestinal/métodos , Adesivos Teciduais/efeitos adversos , Recidiva
7.
Zhongguo Gu Shang ; 37(1): 26-32, 2024 Jan 25.
Artigo em Chinês | MEDLINE | ID: mdl-38286448

RESUMO

OBJECTIVE: To observe the alteration of thoracic and lumbar physiological curvature in adolescent idiopathic scoliosis(AIS) and the difference of physiological curvature between different types of scoliosis. METHODS: A retrospective analysis was conducted on 305 adolescent patients taken full spine X-ray in our hospital from January 2017 to December 2021. The patients were divided into normal group and scoliosis group. The normal group was composed of 179 patients, 79 males and 100 females, aged 10 to 18 years old with an average of (12.84±2.10) years old, with cobb agle less than 10 degrees. The scoliosis group was composed of 126 patients, 33 males and 93 females, aged 10 to 18 years old with an average of (13.92±2.20) years old. The gender, age, Risser sign, thoracic kyphosis(TK) and lumbar lordosis(LL) in 2 groups were compared, and the TK and LL were also compared between different genders, different degrees of scoliosis and different segments of scoliosis. RESULTS: The female ratio(P=0.001) and age (P<0.001) in scoliosis group were higher than them in normal group; the ratio of low-grade ossification was higher in normal group than in scoliosis group(P=0.038). TK was significantly smaller in scoliosis group than in normal group(P<0.001), but there was no significant difference in LL between the 2 groups(P=0.147). There were no significant difference in TK and LL between male and female. The TK was significantly bigger in mild AIS patients than in moderate AIS patients(P<0.05), but there was no significant difference in LL between mild and moderate patients(P>0.05). The TK and LL in different segments scoliosis were not found significant difference. CONCLUSION: The physiological curvature of thoracic and lumbar spine is independent of gender. The thoracic physiological curvature becomes smaller in AIS patients, but lumbar curvature remains unchanged. The thoracic physiological curvature in mild AIS patients is greater than that in moderate AIS patients, but the lumbar curvature is almost unchanged between mild and moderate scoliosis and is similar with that in normal adolescent. The alteration of thoracic and lumbar physiological curvature in AIS patients may be related to relative anterior spinal overgrowth, and the specific detailed mechanism needs to be further studied.


Assuntos
Cifose , Lordose , Escoliose , Fusão Vertebral , Feminino , Humanos , Masculino , Adolescente , Criança , Escoliose/diagnóstico por imagem , Estudos Retrospectivos , Vértebras Torácicas/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Fusão Vertebral/métodos
8.
Anal Methods ; 15(38): 5087-5094, 2023 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-37747357

RESUMO

Acetochlor is an endocrine disruptor. The acetochlor residue is strongly lipophilic and can be enriched into products during the manufacturing process. In this study, we found that dimethyl-ß-cyclodextrin (DM-ß-CD) solution could decrease the apparent oil/water partition coefficient (Koil-w) of acetochlor and increase the sensitivity of fluorescence lateral flow immunoassay (LFIA) for acetochlor simultaneously. Based on this, a simple LFIA method for the determination of acetochlor and alachlor residues in vegetable oil was established. The detection process only involves vortex mixing of an oil sample and dimethyl-ß-cyclodextrin solution in a 1 : 3 (V/V) ratio, loading the water phase onto the immunoassay strips and reading the results. Under optimized conditions, the LOD for acetochlor in oil was 3.53 ng g-1, and the working range was 12.03-2000.00 ng g-1. The recoveries of spiked samples ranged from 91.69% ± 1.12% to 112.23% ± 2.20%. Meanwhile, the cross reactivity for alachlor was 108.22%, while for other investigated acetochlor analogues it was less than 1%, and the recoveries of alachlor were from 92.90% ± 8.03% to 113.53% ± 3.40%, which indicate that this method can detect acetochlor and alachlor simultaneously. Compared with the traditional detection method, the pre-treatment process of the proposed method is "green" and simple, and can be applied to the on-site rapid detection of acetochlor and alachlor in vegetable oil and can provide inspiration for the detection of other lipophilic pollutants.

9.
BMC Public Health ; 23(1): 1737, 2023 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-37674119

RESUMO

BACKGROUND: Bangladesh is one of the countries at risk of natural disasters due to climate change. In particular, inhabitants of its riverine islands (char) confront ongoing climatic events that heighten their vulnerability. This study aims to assess social vulnerability, impacts, and adaptation strategies to climate change in the riverine island areas of Bangladesh. METHODS: A mixed-method approach incorporating qualitative and quantitative procedures was used on data collected from 180 households of riverine islands in Gaibandha, Bangladesh. The social vulnerability of riverine island communities was assessed based on their adaptation capacity, sensitivity, and exposure to climatic stressors. RESULTS: The findings show that char dwellers' vulnerability, impacts, and adaptation capability to climate change vary significantly depending on their proximity to the mainland. Social vulnerability factors such as geographical location, fragile and low-grade housing conditions, illiteracy and displacement, climate-sensitive occupation and low-income level, and so on caused to the in-height vulnerability level of these particular areas. This study also displays that climate change and its associated hazards cause severe life and livelihood concerns for almost all households. In this case, the riverine dwellers employed several adaptation strategies to enhance their way of life to the disaster brought on changing climate. However, low education facilities, deficiency of useful information on climate change, poor infrastructure, and shortage of money are still the supreme hindrance to the sustainability of adaptation. CONCLUSION: The findings underscore the importance of evaluating the susceptibility of local areas to climate change and emphasize the need for tailored local initiatives and policies to reduce vulnerability and enhance adaptability in communities residing in char households.


Assuntos
Aclimatação , Vulnerabilidade Social , Humanos , Bangladesh , Mudança Climática , Ilhas , Rios
10.
Artigo em Inglês | MEDLINE | ID: mdl-37453026

RESUMO

A high ethanol usage of alcohol oxidase (AOX) was required in industry. In this study, a "expand substrate pocket" strategy achieved a high activity AOX from Hansenula polymorpha (H. polymorpha) by Phe to Val residue (F/V) site-directed mutation to enlarge ethanol channel. Although H. Polymorpha AOX (HpAOX) possessed respectively 71.3% and 76.1% similarity with AOX (PpAOX) from Pichia pastoris (P. pastoris) in DNA and protein sequences, their active site structures including catalytic site and substrate channel were similar according to computer-aided analysis. After 3D structure analysis, Phe99 residue of their substrate channels was the most important residue to impact enzyme activity because of its large aromatic side chains. F99V mutation of HpAOX (HpAOXF99V) was designed and executed based on the enzyme catalytic mechanism and molecular computation in order to allow more larger size ethanol into active site. The highest enzyme activity of the fourth strains of HpAOXF99V mutant strain exhibited 12.06-folds increase than that of the host GS115 strain. Furthermore, kinetic studies indicated that the HpAOXF99V significantly promoted catalytic efficiency of ethanol than HpAOX, including Km, Vmax, kcat and kcat/Km. We also provided a new insight that the cofactor FAD irritated both active AOX octamer biosynthesis production and enzyme-catalysed ability due to help enzyme assembly and redox potential.

11.
Sci Rep ; 13(1): 12219, 2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37500814

RESUMO

In the hope of reducing the air supply flow of the powered air-purifying respirator (PAPR) and extending the service life of the filter, a breath-following powered air-purifying respirator (BF-PAPR) that can dynamically adjust the air supply flow according to the breathing flow is proposed. The BF-PAPR changes the air supply flow by adjusting the speed of the variable-frequency centrifugal fan according to the air velocity at the half mask outlet (vhm) monitored by the modular wind speed transmitter. In the study, the air supply flow adjustment model of the BF-PAPR is developed. It is found that the filtration resistance barely influences vhm. In addition, under the same mean inhalation flow, the minimum outlet air velocity increases first and then decreases with the increase of the duty cycle variation coefficient (λ), while the maximum outlet air velocity decreases first and then increases. Moreover, the minimum air supply flow of the BF-PAPR is achieved when the standard value of the air velocity is 13.4 m/s and the value of λ is 1. The BF-PAPR can reduce the air supply flow by 6.5%-8.6% and the energy consumption by approximately 20% compared with the PAPR, which is beneficial for reducing the usage cost and extending the continuous working time.

12.
Sustain Sci ; : 1-18, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37363316

RESUMO

China produces nearly half of the world's coal and more than half of the global coal-fired electricity. Its CO2 emissions are higher than the combined volumes of the next three world regions-the US, Europe, and India. China has announced a net-zero commitment by 2060. This timeline creates enormous pressure to maintain energy security while phasing down coal use. Despite the localized nature of China's coal production with nearly 80% of its thermal coal industry concentrated in four provinces, the dependencies are complex and extensive. Large-scale changes to energy systems will result in a range of social, cultural, and economic disruptions across China's urban, rural, and remote regions. This paper examines experiences with coal transitions in other jurisdictions and considers implications for China. We examine the drivers, successes, and failures of coal phase-down in Germany, Poland, Australia, the UK, and the US. Despite significant differences in scale and complexity, these experiences offer important insights for China as it works to meet its climate commitments.

13.
Molecules ; 28(7)2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-37050023

RESUMO

The common mycotoxins in polluted grains are aflatoxin B1(AFB1), zearalenone (ZEN) and deoxynivalenol (DON). Because of the potential threat to humans and animals, it is necessary to detect mycotoxin contaminants rapidly. At present, later flow immunoassay (LFIA) is one of the most frequently used methods for rapid analysis. However, multistep sample pretreatment processes and organic solvents are also required to extract mycotoxins from grains. In this study, we developed a one-step and "green" sample pretreatment method without using organic solvents. By combining with LFIA test strips and a handheld detection device, an on-site method for the rapid detection of AFB1, ZEN and DON was developed. The LODs for AFB1, ZEN and DON in corn are 0.90 µg/kg, 7.11 µg/kg and 10.6 µg/kg, respectively, and the working ranges are from 1.25 µg/kg to 40 µg/kg, 20 µg/kg to 2000 µg/kg and 35 µg/kg to 1500 µg/kg, respectively. This method has been successfully applied to the detection of AFB1, ZEN and DON in corn, rice and peanut, with recoveries of 89 ± 3%-106 ± 3%, 86 ± 2%-108 ± 7% and 90 ± 2%-106 ± 10%, respectively. The detection results for the AFB1, ZEN and DON residues in certified reference materials by this method were in good agreement with their certificate values.


Assuntos
Micotoxinas , Oryza , Zearalenona , Animais , Humanos , Arachis , Aflatoxina B1 , Zea mays , Micotoxinas/análise , Contaminação de Alimentos/análise
14.
China CDC Wkly ; 5(11): 248-254, 2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-37009170

RESUMO

Introduction: On December 7, 2022, China implemented "Ten New Measures" to optimize prevention and control measures for coronavirus disease 2019 (COVID-19). The purpose of this study was to evaluate the national and regional trends of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among couriers in China from December 2022 to January 2023. Methods: Data from the National Sentinel Community-based Surveillance in China was utilized, including participants from 31 provincial-level administrative divisions and Xinjiang Production and Construction Corps. Participants were tested for SARS-CoV-2 infection twice a week from December 16, 2022 to January 12, 2023. Infection was defined as a positive result for SARS-CoV-2 nucleic acid or antigen. The daily average newly positive rate of SARS-CoV-2 infection and the estimated daily percentage change (EDPC) were calculated. Results: In this cohort, 8 rounds of data were collected. The daily average newly positive rate of SARS-CoV-2 infection decreased from 4.99% in Round 1 to 0.41% in Round 8, with an EDPC of -33.0%. Similar trends of the positive rate were also observed in the eastern (EDPC: -27.7%), central (EDPC: -38.0%) and western regions (EDPC: -25.5%). Couriers and community population showed a similar temporal trend, with the peak daily average newly positive rate of couriers being higher than that of community population. After Round 2, the daily average newly positive rate of couriers decreased sharply, becoming lower than that of community population in the same period. Conclusions: The peak of SARS-CoV-2 infection among couriers in China has passed. As couriers are a key population for SARS-CoV-2 infection, they should be monitored continuously.

15.
China CDC Wkly ; 5(11): 241-247, 2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-37009172

RESUMO

Introduction: In late 2022, a rapid transmission of Omicron variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred throughout China. The purpose of this study was to provide the latest data and evaluate trends of SARS-CoV-2 infection in rural China among the community population. Methods: Data on SARS-CoV-2 infection among approximately 90,000 participants in rural China were collected by the National Sentinel Community-Based Surveillance (NSCS) system. Participants were tested for SARS-CoV-2 infection (defined as positive for SARS-CoV-2 nucleic acid or antigen) twice weekly from December 16, 2022 to January 12, 2023. The daily average of newly positive rate and its estimated daily percentage change were calculated to describe the national and regional trends of SARS-CoV-2 infection in rural China. Results: In rural China, the daily average new positive rate of SARS-CoV-2 infection peaked at 4.79% between December 20-22, 2022 and then decreased to 0.57% between January 10-12, 2023, with an average decrease of 29.95% per round. The peak of new SARS-CoV-2 infection was slightly earlier and lower in North China (5.28% between December 20-22, 2022) than in South China (5.63% between December 23-26, 2022), and then converged from December 30, 2022 to January 2, 2023. The peak of 6.09% occurred between December 20-22, 2022 in eastern China, while the peak of 5.99% occurred later, between December 27-29, 2022, in central China. Conclusions: Overall, the epidemic wave in rural China peaked between December 20-22, 2022, and passed quickly following the optimization of prevention and control measures. Currently, SARS-CoV-2 infection in community populations in rural China is sporadic.

17.
IEEE Trans Cybern ; 53(9): 5970-5983, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37015577

RESUMO

In this article, both the fixed-time distributed consensus tracking and the fixed-time distributed average tracking problems for double-integrator-type multiagent systems with bounded input disturbances are studied. First, a new practical robust fixed-time sliding-mode control method based on the time-based generator is proposed. Second, two fixed-time distributed consensus tracking observers for double-integrator-type multiagent systems are designed to estimate the state disagreement between the leader and the followers under undirected and directed communication, respectively. Third, a fixed-time distributed average tracking observer for double-integrator-type multiagent systems is designed to measure the average value of multiple reference signals under undirected communication. Note that all the proposed observers are constructed with time-based generators and can be trivially extended to that for high-order integrator-type multiagent systems. Furthermore, by combining the proposed fixed-time sliding-mode control method with the information provided by the fixed-time observers, the fixed-time controllers are designed to solve the fixed-time distributed consensus tracking and the distributed average tracking problems. Finally, a few numerical simulations are shown to verify the results.

20.
PLoS One ; 18(2): e0282026, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36809282

RESUMO

Pressure drop is an important indicator that affects the filtration performance of the pleated filter, and the deposition of dust particles within the pleats is crucial to the evolution of the pressure drop. In this study, the pressure drop during PM10 loading process was investigated for a series of V-shaped and U-shaped filters with a pleat height of 20 mm and different pleat ratios (the ratio of pleat height to pleat width: α = 0.71-3.57). In the numerical simulations, numerical models suitable for different pleated geometries were obtained through experimental verification on the local air velocity. Then, assuming that the dust cake thickness is proportional to the normal air velocity of the filters, the variation of the pressure drop with the dust deposition is derived by means of successive numerical simulations. This simulation method saved a significant amount of CPU time required for the growth of dust cake. It was found that the relative average deviations between experimental and simulated pressure drops were 3.12% and 1.19% for V-shaped and U-shaped filters, respectively. Furthermore, it was found that under the same pleat ratio and the mass of dust deposition per unit area, both the pressure drop and unevenness of normal air velocity of the U-shaped filter were lower than the V-shaped filter. Therefore, the U-shaped filter is recommended due to its better filtration performance.


Assuntos
Filtros de Ar , Poeira , Filtração/métodos , Alimentos
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