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1.
Nature ; 577(7788): 60-63, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31894149

RESUMO

The formation and growth of water-ice layers on surfaces and of low-dimensional ice under confinement are frequent occurrences1-4. This is exemplified by the extensive reporting of two-dimensional (2D) ice on metals5-11, insulating surfaces12-16, graphite and graphene17,18 and under strong confinement14,19-22. Although structured water adlayers and 2D ice have been imaged, capturing the metastable or intermediate edge structures involved in the 2D ice growth, which could reveal the underlying growth mechanisms, is extremely challenging, owing to the fragility and short lifetime of those edge structures. Here we show that noncontact atomic-force microscopy with a CO-terminated tip (used previously to image interfacial water with minimal perturbation)12, enables real-space imaging of the edge structures of 2D bilayer hexagonal ice grown on a Au(111) surface. We find that armchair-type edges coexist with the zigzag edges usually observed in 2D hexagonal crystals, and freeze these samples during growth to identify the intermediate edge structures. Combined with simulations, these experiments enable us to reconstruct the growth processes that, in the case of the zigzag edge, involve the addition of water molecules to the existing edge and a collective bridging mechanism. Armchair edge growth, by contrast, involves local seeding and edge reconstruction and thus contrasts with conventional views regarding the growth of bilayer hexagonal ices and 2D hexagonal matter in general.


Assuntos
Gelo , Microscopia de Tunelamento , Cristalização
2.
Small ; : e2402402, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949051

RESUMO

Doping transition metal oxide spinels with metal ions represents a significant strategy for optimizing the electronic structure of electrocatalysts. Herein, a bimetallic Fe and Ru doping strategy to fine-tune the crystal structure of CoV2O4 spinel for highly enhanced oxygen evolution reaction (OER) is presented performance. The incorporation of Fe and Ru is observed at octahedral sites within the CoV2O4 structure, effectively modulating the electronic configuration of Co. Density functional theory calculations have confirmed that Fe acts as a novel reactive site, replacing V. Additionally, the synergistic effect of Fe, Co, and Ru effectively optimizes the Gibbs free energy of the intermediate species, reduces the reaction energy barrier, and accelerates the kinetics toward OER. As expected, the best-performing CoVFe0.5Ru0.5O4 displays a low overpotential of 240 mV (@10 mA cm-2) and a remarkably low Tafel slope of 38.9 mV dec-1, surpassing that of commercial RuO2. Moreover, it demonstrates outstanding long-term durability lasting for 72 h. This study provides valuable insights for the design of highly active polymetallic spinel electrocatalysts for energy conversion applications.

3.
Cardiovasc Diabetol ; 23(1): 86, 2024 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-38419039

RESUMO

BACKGROUND: Studies on the relationship between insulin resistance (IR) surrogates and long-term all-cause mortality in patients with coronary heart disease (CHD) and hypertension are lacking. This study aimed to explore the relationship between different IR surrogates and all-cause mortality and identify valuable predictors of survival status in this population. METHODS: The data came from the National Health and Nutrition Examination Survey (NHANES 2001-2018) and National Death Index (NDI). Multivariate Cox regression and restricted cubic splines (RCS) were performed to evaluate the relationship between homeostatic model assessment of IR (HOMA-IR), triglyceride glucose index (TyG index), triglyceride glucose-body mass index (TyG-BMI index) and all-cause mortality. The recursive algorithm was conducted to calculate inflection points when segmenting effects were found. Then, segmented Kaplan-Meier analysis, LogRank tests, and multivariable Cox regression were carried out. Receiver operating characteristic (ROC) and calibration curves were drawn to evaluate the differentiation and accuracy of IR surrogates in predicting the all-cause mortality. Stratified analysis and interaction tests were conducted according to age, gender, diabetes, cancer, hypoglycemic and lipid-lowering drug use. RESULTS: 1126 participants were included in the study. During the median follow-up of 76 months, 455 participants died. RCS showed that HOMA-IR had a segmented effect on all-cause mortality. 3.59 was a statistically significant inflection point. When the HOMA-IR was less than 3.59, it was negatively associated with all-cause mortality [HR = 0.87,95%CI (0.78, 0.97)]. Conversely, when the HOMA-IR was greater than 3.59, it was positively associated with all-cause mortality [HR = 1.03,95%CI (1.00, 1.05)]. ROC and calibration curves indicated that HOMA-IR was a reliable predictor of survival status (area under curve = 0,812). No interactions between HOMA-IR and stratified variables were found. CONCLUSION: The relationship between HOMA-IR and all-cause mortality was U-shaped in patients with CHD and hypertension. HOMA-IR was a reliable predictor of all-cause mortality in this population.


Assuntos
Doença das Coronárias , Hipertensão , Resistência à Insulina , Humanos , Estudos Longitudinais , Inquéritos Nutricionais , Glicemia , Estudos de Coortes , Hipertensão/diagnóstico , Doença das Coronárias/diagnóstico , Triglicerídeos , Glucose , Biomarcadores
4.
Phys Rev Lett ; 132(8): 086101, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38457702

RESUMO

The exploration of solid-solid phase transition suffers from the uncertainty of how atoms in two crystal structures match. We devised a theoretical framework to describe and classify crystal-structure matches (CSM). Such description fully exploits the translational and rotational symmetries and is independent of the choice of supercells. This is enabled by the use of the Hermite normal form, an analog of reduced echelon form for integer matrices. With its help, exhausting all CSMs is made possible, which goes beyond the conventional optimization schemes. In an example study of the martensitic transformation of steel, our enumeration algorithm finds many candidate CSMs with lower strains than known mechanisms. Two long-sought CSMs accounting for the most commonly observed Kurdjumov-Sachs orientation relationship and the Nishiyama-Wassermann orientation relationship are unveiled. Given the comprehensiveness and efficiency, our enumeration scheme provide a promising strategy for solid-solid phase transition mechanism research.

5.
Nature ; 563(7729): E18, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30135587

RESUMO

In this Letter, the links to Supplementary Videos 5, 7, 9 and 10 were incorrect, and there were some formatting errors in the Supplementary Video legends. These errors have been corrected online.

6.
Nature ; 557(7707): 701-705, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29760468

RESUMO

Ion hydration and transport at interfaces are relevant to a wide range of applied fields and natural processes1-5. Interfacial effects are particularly profound in confined geometries such as nanometre-sized channels6-8, where the mechanisms of ion transport in bulk solutions may not apply9,10. To correlate atomic structure with the transport properties of hydrated ions, both the interfacial inhomogeneity and the complex competing interactions among ions, water and surfaces require detailed molecular-level characterization. Here we constructed individual sodium ion (Na+) hydrates on a NaCl(001) surface by progressively attaching single water molecules (one to five) to the Na+ ion using a combined scanning tunnelling microscopy and noncontact atomic force microscopy system. We found that the Na+ ion hydrated with three water molecules diffuses orders of magnitude more quickly than other ion hydrates. Ab initio calculations revealed that such high ion mobility arises from the existence of a metastable state, in which the three water molecules around the Na+ ion can rotate collectively with a rather small energy barrier. This scenario would apply even at room temperature according to our classical molecular dynamics simulations. Our work suggests that anomalously high diffusion rates for specific hydration numbers of ions are generally determined by the degree of symmetry match between the hydrates and the surface lattice.

7.
Exp Appl Acarol ; 92(2): 297-305, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38351236

RESUMO

As one of the most important disease vectors worldwide, ticks can transmit a number of pathogenic organisms to humans and domestic animals and cause a variety of important natural focal diseases and zoonoses. Domestic livestock play a vital role in the dispersal of ticks from the field environment to the human settlement, contributing to the prevalence of tick-borne diseases. Identification of the tick control region could contribute a vital role in strategic planning and cost-effective tick control measures. However, little is known about the spatial distribution characteristics of ticks around livestock sheds, which will lead to abusage and overuse of insecticides. Therefore, this study aimed to explore spatial distribution characteristics and correlation factors of ticks around goat sheds. A total of 3898 ticks were collected from eight goat sheds from April to June in Jinan city. All the sampled ticks belonged to the same species, namely Haemaphysalis longicornis, and 88.8% of them were nymphs. A significant positive correlation was noted between free-living ticks and parasitic ticks (r = 0.411, P < 0.001). However, there was a significant negative correlation between number of free-living ticks and distance from the goat sheds (r = -0.622, P < 0.001). Within 20 m from the goat sheds, 2211 ticks were collected respectively, representing 56.7% of the total free-living ticks. At a distance of 30 m, 57.6% decline in the tick density was found with a significant difference (q = 5.534, P < 0.001). In conclusion, focusing control efforts near the goat sheds should be recommend for tick prevention and control.


Assuntos
Ixodidae , Carrapatos , Animais , Humanos , Cabras , Haemaphysalis longicornis , Animais Domésticos , China/epidemiologia , Gado
8.
Small ; 19(9): e2205246, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36581560

RESUMO

Boosting charge separation and transfer of photoanodes is crucial for providing high viability of photoelectrochemical hydrogen (H2 ) generation. Here, a structural engineering strategy is designed and synthesized for uniformly coating an ultrathin CoFe bimetal-organic framework (CoFe MOF) layer over a BiVO4 photoanode for boosted charge separation and transfer. The photocurrent density of the optimized BiVO4 /CoFe MOF(NA) photoanode reaches a value of 3.92 mA cm-2 at 1.23 V versus reversible hydrogen electrode (RHE), up to 6.03 times that of pristine BiVO4 , due to the greatly increased efficiency of charge transfer and separation. In addition, this photoanode records one onset potential that is considerably shifted negatively when compared to BiVO4 . Transient absorption spectroscopy reveals that the CoFe MOF(NA) prolongs charge recombination lifetime by blocking the hole-transfer pathway from the BiVO4 to its surface trap states. This work sheds light on boosting charge separation and transfer through structural engineering to enhance the photocurrent of photoanodes for solar H2 production.

9.
J Phys Chem A ; 127(13): 2902-2911, 2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-36949622

RESUMO

We applied the harmonic inversion technique to extract vibrational eigenvalues from the semiclassical initial value representation (SC-IVR) propagator of molecular systems described by explicit potential surfaces. The cross-correlation filter-diagonalization (CCFD) method is used for the inversion problem instead of the Fourier transformation, which allows much shorter propagation time and is thus capable of avoiding numerical divergence issues while getting rid of approximations like the separable one to the pre-exponential factor. We also used the "Divide-and-Conquer" technique to control the total dimensions under consideration, which helps to further enhance the numerical behavior of SC-IVR calculations and the stability of harmonic inversion methods. The technique is tested on small molecules and water trimer to justify its applicability and reliability. Results show that the CCFD method can effectively extract the vibrational eigenvalues from short trajectories and reproduce the original spectra conventionally obtained from long-time ones, with no loss on accuracy while the numerical behavior is much better. This work demonstrates the possibility to apply the combined method of CCFD and SC-IVR to real molecular potential surfaces, which might be a new way to overcome the numerical instabilities caused by the increase of dimensions.

10.
J Chem Phys ; 158(22)2023 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-37290067

RESUMO

Tunneling splittings observed in molecular rovibrational spectra are significant evidence for tunneling motion of hydrogen nuclei in water clusters. Accurate calculations of the splitting sizes from first principles require a combination of high-quality inter-atomic interactions and rigorous methods to treat the nuclei with quantum mechanics. Many theoretical efforts have been made in recent decades. This Perspective focuses on two path-integral based tunneling splitting methods whose computational cost scales well with the system size, namely, the ring-polymer instanton method and the path-integral molecular dynamics (PIMD) method. From a simple derivation, we show that the former is a semiclassical approximation to the latter, despite that the two methods are derived very differently. Currently, the PIMD method is considered to be an ideal route to rigorously compute the ground-state tunneling splitting, while the instanton method sacrifices some accuracy for a significantly smaller computational cost. An application scenario of such a quantitatively rigorous calculation is to test and calibrate the potential energy surfaces of molecular systems by spectroscopic accuracy. Recent progress in water clusters is reviewed, and the current challenges are discussed.


Assuntos
Teoria Quântica , Água , Simulação de Dinâmica Molecular , Hidrogênio/química , Polímeros
11.
Nano Lett ; 22(7): 2725-2733, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35293751

RESUMO

In van der Waals (vdW) heterostructures, the interlayer electron-phonon coupling (EPC) provides one unique channel to nonlocally engineer these elementary particles. However, limited by the stringent occurrence conditions, the efficient engineering of interlayer EPC remains elusive. Here we report a multitier engineering of interlayer EPC in WS2/boron nitride (BN) heterostructures, including isotope enrichments of BN substrates, temperature, and high-pressure tuning. The hyperfine isotope dependence of Raman intensities was unambiguously revealed. In combination with theoretical calculations, we anticipate that WS2/BN supercells could induce Brillouin-zone-folded phonons that contribute to the interlayer coupling, leading to a complex nature of broad Raman peaks. We further demonstrate the significance of a previously unexplored parameter, the interlayer spacing. By varying the temperature and high pressure, we effectively manipulated the strengths of EPC with on/off capabilities, indicating critical thresholds of the layer-layer spacing for activating and strengthening interlayer EPC. Our findings provide new opportunities to engineer vdW heterostructures with controlled interlayer coupling.

12.
J Am Chem Soc ; 144(46): 21356-21362, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36350126

RESUMO

Using a full-dimensional quantum method for nuclei and a new first-principles water potential, we show that the torsional tunneling splitting in a water trimer can be reproduced with accuracy up to ∼1 cm-1. We quantify the coupling constants of the nuclear quantum states between nonadjacent wells and show that they are the main reason for shifting the quartet-split levels in spectra from a 1:2:1 spacing. This demonstrates the limitation of treatments using simplified models such as the Hückel model and emphasizes the nonlocal nature of the quantum interactions in this system. With such an ab initio endeavor, we examine the quality of the water potential developed and provide a rigorous scheme to decipher the experimental spectra with unprecedented accuracy, which is applicable to more general systems.

13.
J Chem Phys ; 156(12): 124304, 2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35364863

RESUMO

Isotope substitution is an important experimental technique that offers deep insight into reaction mechanisms, as the measured kinetic isotope effects (KIEs) can be directly compared with theory. For multiple proton transfer processes, there are two types of mechanisms: stepwise transfer and concerted transfer. The Bell-Limbach model provides a simple theory to determine whether the proton transfer mechanism is stepwise or concerted from KIEs. Recent scanning tunneling microscopy (STM) experiments have studied the proton switching process in water tetramers on NaCl(001). Theoretical studies predict that this process occurs via a concerted mechanism; however, the experimental KIEs resemble the Bell-Limbach model for stepwise tunneling, raising questions on the underlying mechanism or the validity of the model. We study this system using ab initio instanton theory, and in addition to thermal rates, we also considered microcanonical rates, as well as tunneling splittings. The instanton theory predicts a concerted mechanism, and the KIEs for tunneling rates (both thermal and microcanonical) upon deuteration are consistent with the Bell-Limbach model for concerted tunneling but could not explain the experiments. For tunneling splittings, partial and full deuteration change the size of it in a similar fashion to how they change the rates. We further examined the Bell-Limbach model in another system, porphycene, which has both stepwise and concerted tunneling pathways. The KIEs predicted by instanton theory are again consistent with the Bell-Limbach model. This study highlights differences between KIEs in stepwise and concerted tunneling and the discrepancy between theory and recent STM experiments. New theory/experiments are desired to settle this problem.

14.
Pestic Biochem Physiol ; 187: 105218, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36127060

RESUMO

The Chinese wheat aphid Sitobion miscanthi (CWA) is an important harmful pest in wheat fields. Imidacloprid plays a critical role in controlling pests with sucking mouthparts. However, imidacloprid-resistant pests have been observed after insecticide overuse. Point mutations and low expression levels of the nicotinic acetylcholine receptor ß1 (nAchRß1) subunit are the main imidacloprid-resistant mechanisms. However, the regulatory mechanism underlying nAChRß1 subunit expression is poorly understood. In this study, a target of miR-263b was isolated from the 5'UTR of the nAchRß1 subunit in the CWA. Low expression levels were found in the imidacloprid-resistant strain CWA. Luciferase reporter assays showed that miR-263b could combine with the 5'UTR of the nAChRß1 subunit and suppress its expression by binding to a site in the CWA. Aphids treated with the miR-263b agomir exhibited a significantly reduced abundance of the nAchRß1 subunit and increased imidacloprid resistance. In contrast, aphids treated with the miR-263b antagomir exhibited significantly increased nAchRß1 subunit abundance and decreased imidacloprid resistance. These results provide a basis for an improved understanding of the posttranscriptional regulatory mechanism of the nAChRß1 subunit and further elucidate the function of miRNAs in regulating susceptibility to imidacloprid in the CWA. These results provide a better understanding of the mechanisms of posttranscriptional regulation of nAChRß1 and will be helpful for further studies on the role of miRNAs in the regulation of nAChRß1 subunit resistance in homopteran pests.


Assuntos
Afídeos , Inseticidas , MicroRNAs , Receptores Nicotínicos , Regiões 5' não Traduzidas , Animais , Antagomirs , Afídeos/genética , Afídeos/metabolismo , Resistência a Inseticidas/genética , Inseticidas/farmacologia , MicroRNAs/genética , Neonicotinoides , Nitrocompostos , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo
15.
Phys Rev Lett ; 126(18): 185501, 2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34018788

RESUMO

Starting from Shannon's definition of dynamic entropy, we propose a theory to describe the rare-event-determined dynamic states in condensed matter and their transitions and apply it to high-pressure ice VII. A dynamic intensive quantity named dynamic field, rather than the conventional thermodynamic intensive quantities such as temperature and pressure, is taken as the controlling variable. The dynamic entropy versus dynamic field curve demonstrates two dynamic states in the stability region of ice VII and dynamic ice VII. Their microscopic differences were assigned to the dynamic patterns of proton transfer. This study puts a similar dynamical theory used in earlier studies of glass models on a simpler and more fundamental basis, which could be applied to describe the dynamic states of more realistic condensed matter systems.

16.
Surg Today ; 51(5): 695-702, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33128594

RESUMO

PURPOSE: To explore the role of indocyanine green (ICG) fluorescence navigation in laparoscopic hepatectomy and investigate if the timing of its administration influences the intraoperative observation. METHODS: The subjects of this retrospective study were 120 patients who underwent laparoscopic hepatectomy; divided into an ICG-FN group (n = 57) and a non-ICG-FN group (n = 63). We analyzed the baseline data and operative data. RESULTS: There were no remarkable differences in baseline data such as demographic characteristics, lesion-related characteristics, and liver function parameters between the groups. Operative time and intraoperative blood loss were significantly lower in the ICG-FN group. The rate of R0 resection of malignant tumors was comparable in the ICG-FN and non-ICG-FN groups, but the wide surgical margin rate was significantly higher in the ICG-FN group. The administration of ICG 0-3 or 4-7 days preoperatively did not affect the intraoperative fluorescence imaging. Operative time, intraoperative blood loss, and a wide surgical margin correlated with ICG fluorescence navigation. ICG fluorescence navigation helped to minimize intraoperative blood loss and achieve a wide surgical margin. CONCLUSION: ICG fluorescence navigation is safe and efficient in laparoscopic hepatectomy. It helps to achieve a wide surgical margin, which could result in a better prognosis. The administration of ICG 0-3 days preoperatively is acceptable.


Assuntos
Hepatectomia/métodos , Verde de Indocianina/administração & dosagem , Laparoscopia/métodos , Hepatopatias/cirurgia , Fígado/cirurgia , Imagem Óptica/métodos , Cirurgia Assistida por Computador/métodos , Adulto , Idoso , Perda Sanguínea Cirúrgica/prevenção & controle , Perda Sanguínea Cirúrgica/estatística & dados numéricos , Feminino , Humanos , Masculino , Margens de Excisão , Pessoa de Meia-Idade , Duração da Cirurgia , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
17.
Genomics ; 112(2): 1988-1999, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31759120

RESUMO

We analyzed the whole genomes of cecum microbiomes of Ethiopian indigenous chickens from two distinct geographical zones: Afar (AF) district (Dulecha, 730 m above sea level) and Amhara (AM) district (Menz Gera Midir, 3300 m). Through metagenomic analysis we found that microbial populations were mainly dominated by Bacteroidetes and Firmicutes. We identified 2210 common genes in the two groups. LEfSe showed that the distribution of Coprobacter, Geobacter, Cronobacter, Alloprevotella, and Dysgonomonas were more abundant in AF than AM. Analyses using KEGG, eggNOG, and CAZy databases indicated that the pathways of metabolism, genetic information processing, environmental information processing, and cellular process were significantly enriched. Functional abundance was found to be associated with the nutrient absorption and microbial localization of indigenous chickens. We also investigated antibiotic resistant genes and found antibiotics like LSM, cephalosporin, and tetracycline were significantly more abundant in AF than AM.


Assuntos
Galinhas/microbiologia , Farmacorresistência Bacteriana , Microbioma Gastrointestinal , Metagenoma , Animais , Bacteroidetes/genética , Bacteroidetes/patogenicidade , Ceco/microbiologia , Etiópia , Firmicutes/genética , Firmicutes/patogenicidade , Metagenômica/métodos , Sequenciamento Completo do Genoma/métodos
18.
Small ; 16(34): e2003007, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32686340

RESUMO

The design on synthesizing a sturdy, low-cost, clean, and sustainable electrocatalyst, as well as achieving high performance with low overpotential and good durability toward water splitting, is fairly vital in environmental and energy-related subject. Herein, for the first time the growth of sulfur (S) defect engineered self-supporting array electrode composed of metallic Re and ReS2 nanosheets on carbon cloth (referred as Re/ReS2 /CC) via a facile hydrothermal method and the following thermal treatment with H2 /N2 flow is reported. It is expected that, for example, the as-prepared Re/ReS2 -7H/CC for the electrocatalytic hydrogen evolution reaction (HER) under acidic medium affords a quite low overpotential of 42 mV to achieve a current density of 10 mA cm-2 and a very small Tafel slope of 36 mV decade-1 , which are comparable to some of the promising HER catalysts. Furthermore, in the two-electrode system, a small cell voltage of 1.30 V is recorded under alkaline condition. Characterizations and density functional theory results expound that the introduced S defects in Re/ReS2 -7H/CC can offer abundant active sites to advantageously capture electron, enhance the electron transport capacity, and weaken the adsorption free energy of H* at the active sites, being responsible for its superior electrocatalytic performance.

19.
AIDS Res Ther ; 17(1): 46, 2020 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-32703286

RESUMO

BACKGROUND: The COVID-19 has been a severe pandemic all around the world. Nowadays the patient with co-infection of HIV and SARS-CoV-2 was rarely reported. Here we reported a special case with HIV and SARS-CoV-2 co-infection, which showed a prolonged viral shedding duration. CASE PRESENTATION: The patient was infected with HIV 8 years ago through sexual transmission and had the normal CD4+T cell count. She was found SARS-CoV-2 positive using real-time Polymerase Chain Reaction (RT-PCR) during the epidemic. Most importantly, the patient had a prolonged viral shedding duration of SARS-CoV-2 about 28 days. CONCLUSION: The viral shedding duration may be prolonged in people living with HIV. The 14 days isolation strategy might not be long enough for them. The isolation or discharge of these patients needs further confirmation for preventing epidemics.


Assuntos
Antirretrovirais/uso terapêutico , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico , Infecções por HIV/complicações , Pneumonia Viral/diagnóstico , Eliminação de Partículas Virais , Alcinos , Benzoxazinas/administração & dosagem , Betacoronavirus/genética , Betacoronavirus/imunologia , Proteína C-Reativa/análise , Contagem de Linfócito CD4 , COVID-19 , Calafrios , Infecções por Coronavirus/diagnóstico por imagem , Infecções por Coronavirus/tratamento farmacológico , Ciclopropanos , Fadiga , Feminino , Febre , HIV/crescimento & desenvolvimento , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia , Humanos , Hospedeiro Imunocomprometido , Imunoglobulina M/sangue , Lamivudina/administração & dosagem , Pessoa de Meia-Idade , Pandemias , Faringite , Pneumonia Viral/diagnóstico por imagem , Pneumonia Viral/tratamento farmacológico , Reação em Cadeia da Polimerase em Tempo Real , SARS-CoV-2 , Escarro/virologia , Fatores de Tempo , Tomografia Computadorizada por Raios X , Eliminação de Partículas Virais/imunologia , Zidovudina/administração & dosagem
20.
Zhongguo Zhong Yao Za Zhi ; 45(2): 321-330, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-32237314

RESUMO

Atropa belladonna seedlings were used as experimental materials and cultivated by soil culture method. Different concentrations(0,0.05,0.1,0.2,0.5 mmol·L~(-1))of NO donor sodium nitroprusside(SNP) were sprayed on the leaves. The effects of different concentrations of SNP and different treatment time(4,8,12,16 d) on nitrogen metabolism, secondary metabolite content, precursor content of tropane alkaloid synthesis pathway and expression of key enzyme genes under 100 mmol·L~(-1) NaCl stress were studied. The results showed that with the prolongation of salt stress, the nitrogen metabolism and the accumulation of secondary metabolites of A. belladonna were inhibited to some extent. After treatment with different concentrations of exogenous SNP, the ammonium nitrogen content decreased dramatically, and the contents of nitrate nitrogen, free amino acid, soluble protein and the activities of key enzymes of nitrogen metabolism(NR, GS, GDH) were all greatly improved; the contents of precursor amino acids(ornithine, arginine) and polyamines(Put, Spd, Spm) in the secondary metabolic pathway have increased to varying degrees. The qRT-PCR analysis showed that exogenous SNP treatment can effectively promote the high expression of key enzyme genes PMT, TRⅠ and H6H in the secondary metabolic pathway of A. belladonna, and the production of hyoscyamine and scopolamine were increased notably. In summary, the application of appropriate concentration of SNP can effectively alleviate the inhibition of salt stress on the nitrogen metabolism and secondary metabolism of Atropa belladonna, and enhance its salt tolerance. Overall, 0.1 mmol·L~(-1) and 0.2 mmol·L~(-1) SNP treatment achieved the most remarkable effect.


Assuntos
Atropa belladonna/metabolismo , Hiosciamina/análise , Nitrogênio/metabolismo , Escopolamina/análise , Nitroprussiato , Metabolismo Secundário , Cloreto de Sódio , Estresse Fisiológico
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