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1.
Curr Med Res Opin ; 37(6): 917-927, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33729889

RESUMO

BACKGROUND: To develop a sensitive and clinically applicable risk assessment tool identifying coronavirus disease 2019 (COVID-19) patients with a high risk of mortality at hospital admission. This model would assist frontline clinicians in optimizing medical treatment with limited resources. METHODS: 6415 patients from seven hospitals in Wuhan city were assigned to the training and testing cohorts. A total of 6351 patients from another three hospitals in Wuhan, 2169 patients from outside of Wuhan, and 553 patients from Milan, Italy were assigned to three independent validation cohorts. A total of 64 candidate clinical variables at hospital admission were analyzed by random forest and least absolute shrinkage and selection operator (LASSO) analyses. RESULTS: Eight factors, namely, Oxygen saturation, blood Urea nitrogen, Respiratory rate, admission before the date the national Maximum number of daily new cases was reached, Age, Procalcitonin, C-reactive protein (CRP), and absolute Neutrophil counts, were identified as having significant associations with mortality in COVID-19 patients. A composite score based on these eight risk factors, termed the OURMAPCN-score, predicted the risk of mortality among the COVID-19 patients, with a C-statistic of 0.92 (95% confidence interval [CI] 0.90-0.93). The hazard ratio for all-cause mortality between patients with OURMAPCN-score >11 compared with those with scores ≤ 11 was 18.18 (95% CI 13.93-23.71; p < .0001). The predictive performance, specificity, and sensitivity of the score were validated in three independent cohorts. CONCLUSIONS: The OURMAPCN score is a risk assessment tool to determine the mortality rate in COVID-19 patients based on a limited number of baseline parameters. This tool can assist physicians in optimizing the clinical management of COVID-19 patients with limited hospital resources.


Assuntos
COVID-19 , Medição de Risco/métodos , COVID-19/epidemiologia , COVID-19/mortalidade , China , Hospitalização/estatística & dados numéricos , Humanos , Itália , Fatores de Risco
2.
Soft Matter ; 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-32996549

RESUMO

Atomic force microscopy (AFM) has found a wide range of bio-applications in the past few decades due to its ability to measure biological samples in natural environments at a high spatial resolution. AFM has become a key platform in biomedical, bioengineering and drug research fields, enabling mechanical and morphological characterization of live biological systems. Hence, we provide a comprehensive review on recent advances in the use of AFM for characterizing the biomechanical properties of multi-scale biological samples, ranging from molecule, cell to tissue levels. First, we present the fundamental principles of AFM and two AFM-based models for the characterization of biomechanical properties of biological samples, covering key AFM devices and AFM bioimaging as well as theoretical models for characterizing the elasticity and viscosity of biomaterials. Then, we elaborate on a series of new experimental findings through analysis of biomechanics. Finally, we discuss the future directions and challenges. It is envisioned that the AFM technique will enable many remarkable discoveries, and will have far-reaching impacts on bio-related studies and applications in the future.

3.
Cell Metab ; 31(6): 1068-1077.e3, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32369736

RESUMO

Type 2 diabetes (T2D) is a major comorbidity of COVID-19. However, the impact of blood glucose (BG) control on the degree of required medical interventions and on mortality in patients with COVID-19 and T2D remains uncertain. Thus, we performed a retrospective, multi-centered study of 7,337 cases of COVID-19 in Hubei Province, China, among which 952 had pre-existing T2D. We found that subjects with T2D required more medical interventions and had a significantly higher mortality (7.8% versus 2.7%; adjusted hazard ratio [HR], 1.49) and multiple organ injury than the non-diabetic individuals. Further, we found that well-controlled BG (glycemic variability within 3.9 to 10.0 mmol/L) was associated with markedly lower mortality compared to individuals with poorly controlled BG (upper limit of glycemic variability exceeding 10.0 mmol/L) (adjusted HR, 0.14) during hospitalization. These findings provide clinical evidence correlating improved glycemic control with better outcomes in patients with COVID-19 and pre-existing T2D.


Assuntos
Glicemia/análise , Infecções por Coronavirus/mortalidade , Diabetes Mellitus Tipo 2/sangue , Índice Glicêmico/fisiologia , Hiperglicemia/sangue , Pneumonia Viral/mortalidade , Idoso , Betacoronavirus/patogenicidade , COVID-19 , Infecções por Coronavirus/complicações , Infecções por Coronavirus/patologia , Diabetes Mellitus Tipo 2/complicações , Suscetibilidade a Doenças/patologia , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Hiperglicemia/complicações , Hipoglicemiantes/uso terapêutico , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/complicações , Insuficiência de Múltiplos Órgãos/mortalidade , Pandemias , Pneumonia Viral/complicações , Pneumonia Viral/patologia , Estudos Retrospectivos , SARS-CoV-2
4.
Micromachines (Basel) ; 11(5)2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32438680

RESUMO

Cell dielectric properties, a type of intrinsic property of cells, can be used as electrophysiological biomarkers that offer a label-free way to characterize cell phenotypes and states, purify clinical samples, and identify target cancer cells. Here, we present a review of the determination of cell dielectric properties using alternating current (AC) electrokinetic-based microfluidic mechanisms, including electro-rotation (ROT) and dielectrophoresis (DEP). The review covers theoretically how ROT and DEP work to extract cell dielectric properties. We also dive into the details of differently structured ROT chips, followed by a discussion on the determination of cell dielectric properties and the use of these properties in bio-related applications. Additionally, the review offers a look at the future challenges facing the AC electrokinetic-based microfluidic platform in terms of acquiring cell dielectric parameters. Our conclusion is that this platform will bring biomedical and bioengineering sciences to the next level and ultimately achieve the shift from lab-oriented research to real-world applications.

5.
Opt Lett ; 45(8): 2454-2457, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32287257

RESUMO

We report a novel, to the best of our knowledge, method to rapidly characterize different kinds of cells and drug-treated cancer cells using a label-free biomarker of self-rotation in an optoelectrokinetics (OEK)-based microfluidic platform. OEK incorporates optics and electrokinetics into microfluidics, thereby offering a contact-free, label-free, and rapid approach to the cellular manipulation community. Self-rotational behaviors of four different kinds of cells were experimentally investigated by the frequency-sweeping of an AC bias potential in an optically induced nonuniform and irrotational electric field. The results revealed that these kinds of cells displayed a Gaussian distribution versus the AC frequency as well as different self-rotational speeds under the same conditions. Furthermore, the peak self-rotational speed varied from one kind of cell to another, with that of cancer cells higher than that of normal cells. In addition, MCF-7 cells treated by various concentrations of drug showed remarkably different self-rotational speeds. This finding suggests a high potential of developing a new label-free biomarker to rapidly distinguish different kinds of cancer cells and quantitatively monitor the response of cancer patients to various treatments.


Assuntos
Técnicas Citológicas/instrumentação , Dispositivos Lab-On-A-Chip , Fenômenos Ópticos , Equipamentos e Provisões Elétricas , Humanos , Células MCF-7
6.
Micromachines (Basel) ; 11(2)2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32028687

RESUMO

Recently, the engineering structural ceramics as friction and wear components in manufacturing technology and devices have attracted much attention due to their high strength and corrosion resistance. In this study, the tribological properties of Si3N4/Si3N4 sliding pairs were investigated by adding few-layer graphene to base lubricating oil on the lubrication and cooling under different experimental conditions. Test results showed that lubrication and cooling performance was obviously improved with the addition of graphene at high rotational speeds and low loads. For oil containing 0.1 wt% graphene at a rotational speed of 3000 r·min-1 and 40 N loads, the average friction coefficient was reduced by 76.33%. The cooling effect on Si3N4/Si3N4 sliding pairs, however, was optimal at low rotational speeds and high loads. For oil containing 0.05 wt% graphene at a lower rotational speed of 500 r·min-1 and a higher load of 140 N, the temperature rise was reduced by 19.76%. In addition, the wear mark depth would decrease when adding appropriate graphene. The mechanism behind the reduction in friction and anti-wear properties was related to the formation of a lubricating protective film.

7.
Micromachines (Basel) ; 11(1)2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31936694

RESUMO

Optoelectrokinetics (OEK), a fusion of optics, electrokinetics, and microfluidics, has been demonstrated to offer a series of extraordinary advantages in the manipulation and fabrication of micro/nanomaterials, such as requiring no mask, programmability, flexibility, and rapidness. In this paper, we summarize a variety of differently structured OEK chips, followed by a discussion on how they are fabricated and the ways in which they work. We also review how three differently sized polystyrene beads can be separated simultaneously, how a variety of nanoparticles can be assembled, and how micro/nanomaterials can be fabricated into functional devices. Another focus of our paper is on mask-free fabrication and assembly of hydrogel-based micro/nanostructures and its possible applications in biological fields. We provide a summary of the current challenges facing the OEK technique and its future prospects at the end of this paper.

8.
J Mater Res ; 35(16): 2208-2217, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33390659

RESUMO

During the detection of industrial hazardous gases, like formaldehyde (HCHO), the selectivity is still a challenging issue. Herein, an alternative HCHO chemosensor that based on the tin oxide nanoparticles is proposed, which was obtained through a facile hydrothermal method. Gas sensing performances showed that the optimal working temperature located at only 180 °C, the response value of 79 via 50 ppm HCHO was much higher than that of 35 at 230 °C. However, the compromised test temperature was selected as 230 °C, taking into account the faster response/recovery speeds than 180 °C, named 20/23versus 53/60 s, respectively. The response (35) of the SnO2 nanoparticles-based sensor to 50 ppm of HCHO is about 400% higher than that of bulk SnO2 sensor (9), especially when the gas concentration is 1 ppm, SnO2 nanoparticles also has a higher sensitivity which may possibly result from more exposed active sites and small size effect for nanoparticles than for bulk ones. The gas sensor based on SnO2 nanoparticles can be utilized as a promising candidate for practical low-temperature detectors of HCHO due to its higher gas response, excellent response-recovery properties, and perfect selectivity.

9.
Materials (Basel) ; 12(13)2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31288441

RESUMO

In this study, we use an aqueous solution synthesis method to prepare silver perrhenate powders and suspend them into a poly alpha olefin (PAO) base oil with polyoxyethylene octylphenyl ether. Four ball tests and ball-on-disk reciprocating mode are performed to determine how silver perrhenate performs tribologically as a lubricating additive over a wide range of temperatures. The physical and chemical properties, as well as the lubricating mechanisms of the silver perrhenate additive, are characterized via X-ray diffraction, scanning electron microscope, Fourier transformation infrared spectroscopy, Raman spectrum, and X-ray photoelectron spectroscopy. The four-ball test results demonstrate that the oil added with silver perrhenate additive is more effective than the base oil in reducing friction and improving wear resistance, and provides the best lubricating performance when at a concentration of 0.5 wt%. The reciprocating mode findings indicate that the hybrid lubricant exhibits distinctively better tribological properties than the base oil at high temperatures, and its low shear strength and chemical inertness allow for low friction at elevated temperatures. The resulting silver perrhenate layer that incorporates native superalloy oxides on the worn surface can provide lubrication by serving as a barrier that prevents direct contact between the rubbing surfaces at elevated temperatures.

10.
Oncol Lett ; 17(1): 1217-1222, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30655887

RESUMO

Breast cancer is the leading cause of cancer-associated mortality in females. It has an incidence of 1.3 million per year, which increases by 2% annually. In China, breast cancer accounts for 12.2% of all cancer cases. The aim of the present study was to investigate the inhibitory effect of naringenin on triple-negative breast cancer cells. Lactate dehydrogenase and MTT assay was used to investigate the inhibitory effect of naringenin on MDA-MB-231 cell viability. Naringenin reduced the viability of MDA-MB-231 cells by arresting the cell cycle at the G2 phase. Naringenin treatment not only influenced the phase of cell cycle arrest, but also induced apoptosis in a dose-dependent manner. Naringenin treatment also resulted in a significant increase in caspase-3 and caspase-9 activity (P<0.001). Taken together, the results of the present study suggested that naringenin caused an inhibitory effect on MDA-MB-231 cells via induction of apoptosis and inhibition of caspase-3 and -9 activity.

11.
Materials (Basel) ; 11(9)2018 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-30231462

RESUMO

Magnesium perrhenate used as a lubricating additive was prepared by an aqueous solution method in this paper, and was suspended in a base oil poly alpha olefin (PAO6) with the aid of surface active agents (SA). The thermal stability of the mixed oil with/without magnesium perrhenate and surface active agents was investigated by thermogravimetry testing. The influences of magnesium perrhenate as solid lubricating additive on the extreme pressure performance and the friction-reducing properties over a wide temperature range of the mixed lubricants were determined by four-ball tests and ball-on-disc frictional tests for the commercially available silicon nitride ball and a Ni-base superalloy frictional pair. The results revealed that the added magnesium perrhenate did not obviously affect the thermostability and oxidation resistance of the base oil. Meanwhile, it minimized the coefficients of friction and wear scar diameter to a certain extent in the four-ball experimental conditions. Ball-on-disc rubbing tests suggested the mixed oil had a similar lubricating performance to the base oil below the decomposition temperature point. The most significant advancement was the impressive antifriction improvement at the high temperature range, while the friction coefficients of the oil containing magnesium perrhenate compound were obviously below that of the base stock. This better tribological performance of the mixed lubricant was attributed to the native shear susceptible property and chemical stability of magnesium perrhenate under high temperature conditions, which could form an effective durable and stable antifriction layer with the oxides from the superalloy matrix, thereby decreasing the friction in the high-temperature environment.

13.
ACS Appl Mater Interfaces ; 9(21): 17923-17931, 2017 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-28485135

RESUMO

In this work, well-soluble tris(pentafluorophenyl)borane (BCF) is introduced for the first time into 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) as a p-dopant. The conductivity of spiro-OMeTAD films is dramatically enhanced. When the BCF-doped spiro-OMeTAD film is used as a hole-transport layer (HTL) in perovskite solar cells (PSCs), nearly double increase in power conversion efficiency (PCE) is obtained compared to that of the PSCs based on a pristine spiro-OMeTAD HTL. By the introduction of lithium bis(trifluoromethanesulfonyl)imide and 4-tert-butylpyridine into the BCF-doped spiro-OMeTAD film, the conductivity of spiro-OMeTAD film can be further enhanced, and an optimum PCE of 14.65% is obtained. In addition, the average efficiency of the device and the reproducibility of BCF-based PSCs are better than those of FK209-based PSCs. The working mechanism of the BCF doping effect on spiro-OMeTAD is studied in detail. The strong electron-accepting ability, excellent solubility in common organic solvents, and the low cost make BCF a very attractive p-type dopant for spiro-OMeTAD.

14.
ChemSusChem ; 10(10): 2218-2225, 2017 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-28382788

RESUMO

High quality electron-transport layer (ETL) with superior optical and electrical properties is an essential part in high efficient perovskite solar cells (PSCs). In this work, SiW12 -TiO2 mesoporous film is prepared by a facile one-step spin-coating deposition method and successfully applied as ETL in PSCs. Compared with pristine TiO2 -based PSC, the SiW12 -TiO2 -based one shows a remarkable enhanced power conversion efficiency (PCE) from 12.00 to 14.66 %, which is owed to the higher conductivity, electron-extraction efficiency, and well-matched energy level alignment of SiW12 -TiO2 film. Moreover, the SiW12 -TiO2 -based device also shows a good long-time stability in under ambient conditions. This work demonstrates that using polyoxometalates (POMs) to modify the metal-oxide semiconductors is an effective approach for further enhancing the performance of PSCs.


Assuntos
Compostos de Cálcio/química , Condutividade Elétrica , Óxidos/química , Silício/química , Titânio/química , Tungstênio/química , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Difração de Raios X
15.
Dalton Trans ; 43(26): 10057-63, 2014 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-24871909

RESUMO

Rapid and sensitive detection of 2,4,6-trinitrotoluene (TNT) and 4-nitrophenol (4-NP) has attracted considerable attention due to their wide applications as nitroaromatic explosive materials. A novel fluorescence method for TNT and 4-NP based on bovine serum albumin functionalized fluorescent gold nanoclusters (BSA Au-NCs) has been developed. The detection probe BSA Au-NCs can be used as a fluorescent probe for the sensitive and selective detection of TNT and 4-NP simultaneously. A good linearity of fluorescence detection using BSA Au-NCs as a fluorescent probe was observed for TNT and 4-NP concentrations in the range of 10(-8)-5 × 10(-5) M and 10(-9)-5 × 10(-5) M, with a detection limit of 10 nM and 1 nM, respectively. The high specificity of TNT and 4-NP with BSA Au-NCs interactions provided excellent selectivity towards detecting TNT and 4-NP over other relevant nitroaromatic compounds. This system can be applied to test strips to detect TNT and 4-NP with high sensitivity and selectivity. The vapour of TNT and 4-NP can be detected using BSA Au-NCs test paper within 1 min with a detection limit of 10 pM and 1 pM.

16.
Colloids Surf B Biointerfaces ; 69(1): 99-104, 2009 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-19117734

RESUMO

In situ seeding growth of gold nanoparticles (AuNPs) by the reaction of HAuCl4 and NH2OH has been employed in the fabrication of the nanogapped AuNPs film for direct electrical detection of DNA hybridization and DNA cleavage by EcoRI endonuclease. The distance between neighboring gold nanoparticles is less than the length of the probe DNA, implying that the DNA strand could bridge the AuNPs to provide an electron tunneling path between microelectrodes. The double-stranded DNA (dsDNA) formed by hybridization of probe and target DNA is detected by current-voltage (I-V) curve measurements. When dsDNA is cleaved by restriction endonuclease EcoRI, the electron tunneling path can be cut off, which is reflected from the different slopes of I-V curves between dsDNA and dsDNA cleavage by EcoRI in the label-free electrical measurements. The novel and simple method of fabricating the nanogapped AuNPs film by in situ seeding growth could provide a promising bioanalytical platform for studying both DNA-DNA and DNA-protein interactions.


Assuntos
DNA/análise , Desoxirribonuclease EcoRI/análise , Eletroquímica/métodos , Ouro/química , Nanopartículas Metálicas/química , Microeletrodos , Microscopia Eletrônica de Varredura , Fatores de Tempo
17.
J Invertebr Pathol ; 99(1): 57-65, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18621053

RESUMO

Disease epizootics in freshwater culture crustaceans (crab, crayfish and shrimp) gained high attention recently in China, due to intensive developments of freshwater aquacultures. Spiroplasma was identified as a lethal pathogen of the above three freshwater crustaceans in previous studies. Further characterization of these freshwater crustacean Spiroplasma strains were analyzed in the current study. Phylogenetic position was investigated by analysis of partial nucleotide sequences of 16S ribosomal RNA (rRNA), gyrB and rpoB genes, together with complete sequencing of 23S rRNA gene and 16S-23S rRNA intergenetic spacer regions (ISRs). Phylogenetic analysis of these sequences showed that the above-mentioned three freshwater crustacean Spiroplasma strains were identical and had a close relationship with Spiroplasma mirum. Furthermore, the genomic size, serological studies and experimental infection characteristics confirmed that three freshwater crustacean Spiroplasma strains are a single species other than traditional S. mirum. Therefore, these data suggest that a single species of Spiroplasma infects all three investigated freshwater crustaceans in China, and is a potential candidate for a new species within the Spiroplasma genus. These results provide critical information for the further investigations in fresh aquaculture epizootics related to tremor diseases, caused by this infectious agent.


Assuntos
Aquicultura , Astacoidea/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Penaeidae/microbiologia , Filogenia , Spiroplasma/genética , Animais , DNA Bacteriano/análise , DNA Bacteriano/genética , DNA Espaçador Ribossômico/análise , DNA Espaçador Ribossômico/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Interações Hospedeiro-Patógeno , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/análise , RNA Ribossômico 23S/genética , Análise de Sequência de RNA , Spiroplasma/classificação , Spiroplasma/fisiologia , Spiroplasma/ultraestrutura
18.
Zhongguo Yi Liao Qi Xie Za Zhi ; 32(6): 440-2, 2008 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-19253580

RESUMO

A develop of medical discharger of oxygen is presented in the paper. The medical discharge can control, display and print the output data including the time, oxygen discharge the total time and the total oxygen discharge of two channels oxygen synchronously or respectively, Results show that the device is of reasonable design, accurate, measurement simple operation, low cost, real-time display, alarm and controlling the channels oxygen automatically and can print data if necessary. It will be widely used in clinic.


Assuntos
Apresentação de Dados , Oxigenoterapia/instrumentação , Oxigênio/análise , Pesos e Medidas/instrumentação , Desenho de Equipamento , Humanos
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