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1.
Plant Cell ; 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38299372

RESUMEN

Alternative complex III (ACIII) couples quinol oxidation and electron acceptor reduction with potential transmembrane proton translocation. It is compositionally and structurally different from the cytochrome bc1/b6f complexes, but functionally replaces these enzymes in the photosynthetic and/or respiratory electron transport chains (ETCs) of many bacteria. However, the true compositions and architectures of ACIIIs remain unclear, as do their structural and functional relevance in mediating the ETCs. We here determined cryogenic electron microscopy structures of photosynthetic ACIII isolated from Chloroflexus aurantiacus (CaACIIIp), in apo-form and in complexed form bound to a menadiol analog 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO). Besides six canonical subunits (ActABCDEF), the structures revealed conformations of two previously unresolved subunits, ActG and I, which contributed to the complex stability. We also elucidated the structural basis of menaquinol oxidation and subsequent electron transfer along the [3Fe-4S]-6 hemes wire to its periplasmic electron acceptors, using electron paramagnetic resonance (EPR), spectroelectrochemistry, enzymatic analyses and molecular dynamics (MD) simulations. A unique insertion loop in ActE was shown to function in determining the binding specificity of CaACIIIp for downstream electron acceptors. This study broadens our understanding of the structural diversity and molecular evolution of ACIIIs, enabling further investigation of the (mena)quinol oxidoreductases evolved coupling mechanism in bacterial energy conservation.

2.
Nano Lett ; 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38847451

RESUMEN

Nanofiltration membranes with both high water permeance and selectivity are perpetually studied because of their applications in water purification. However, these two critical attributes are considered to be mutually exclusive. Here, we introduce a polar solvent, dichloromethane, in place of the apolar hexane used for decades as the organic phase for membrane interfacial polymerization synthesis to solve this dilemma. When a polar solvent as the organic phase is combined with a solvent-resistant aramid nanofibrous hydrogel film as the water phase, monomer enrichment in the reaction zone leads to a polyamide nanofiltration membrane with densely distributed nanobubble features, enhanced nanoporosity, and a loosened backbone. Benefiting from these structural features, the resulting membrane exhibits superior properties with a combination of high water permeance (52.7 L m-2 h-1 bar-1) and selectivity (water/Na2SO4, 36 bar-1; NaCl/Na2SO4, 357 bar-1), outperforming traditional nanofiltration membranes. We envision that this novel technology involving polar solvent systems and the water phase of nanofibrous hydrogel would provide new opportunities for membrane development for environmental engineering.

3.
Anal Chem ; 96(19): 7772-7779, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38698542

RESUMEN

There is growing attention focused toward the problems of ecological sustainability and food safety raised from the abuse of herbicides, which underscores the need for the development of a portable and reliable sensor for simple, rapid, and user-friendly on-site analysis of herbicide residues. Herein, a novel multifunctional hydrogel composite is explored to serve as a portable and flexible sensor for the facile and efficient analysis of atrazine (ATZ) residues. The hydrogel electrode is fabricated by doping graphite-phase carbon nitride (g-C3N4) into the aramid nanofiber reinforced poly(vinyl alcohol) hydrogel via a simple solution-casting procedure. Benefiting from the excellent electroactivity and large specific surface area of the solid nanoscale component, the prepared hydrogel sensor is capable of simple, rapid, and sensitive detection of ATZ with a detection limit down to 0.002 ng/mL and per test time less than 1 min. After combination with a smartphone-controlled portable electrochemical analyzer, the flexible sensor exhibited satisfactory analytical performance for the ATZ assay. We further demonstrated the applications of the sensor in the evaluation of the ATZ residues in real water and soil samples as well as the user-friendly on-site point-of-need detection of ATZ residues on various agricultural products. We envision that this flexible and portable sensor will open a new avenue on the development of next-generation analytical tools for herbicide monitoring in the environment and agricultural products.


Asunto(s)
Atrazina , Técnicas Electroquímicas , Herbicidas , Hidrogeles , Atrazina/análisis , Herbicidas/análisis , Hidrogeles/química , Técnicas Electroquímicas/instrumentación , Grafito/química , Electrodos , Límite de Detección , Nitrilos/química , Nitrilos/análisis , Nanofibras/química , Contaminantes Químicos del Agua/análisis
4.
BMC Gastroenterol ; 23(1): 292, 2023 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-37653392

RESUMEN

BACKGROUND: Several proteins in the tripartite-motif (TRIM) family are associated with the development of colorectal cancer (CRC), but research on the role of TRIM69 was lacking. The present study examined the correlation between TRIM69 expression and colon adenocarcinoma (COAD). METHODS: mRNA sequencing data for COAD patients was extracted from The Cancer Genome Atlas to analyze correlations between TRIM69 expression and patients' clinical features as well as survival. Potential associations with immune cells and chemosensitivity also were predicted using various algorithms in the TIMER, Limma, clusterProfiler, GeneMANIA, and Gene Set Cancer Analysis platforms. Subsequently, polymerase chain reaction analysis and immunohistochemical staining were used to detect TRIM69 expression in COAD tissue samples from real-world patients. RESULTS: TRIM69 expression was lower in COAD tissues than in normal tissues and correlated with the pathologic stage and metastasis (M category). Additionally, TRIM69 was found to be involved in several immune-related pathways, notably the NOD-like signaling pathway. These results suggest that high TRIM69 expression has the potential to enhance tumor sensitivity to 5-fluorouracil and programmed cell death protein 1 (PD-1) blockers. CONCLUSIONS: From our findings that TRIM69 expression was significantly reduced in COAD compared with non-cancer tissues and associated with pathologic stage and metastasis, we conclude that increasing TRIM69 expression and/or activity may help to improve therapeutic outcomes. Accordingly, TRIM69 represents a potentially valuable marker of metastasis and target for adjuvant therapy in COAD.


Asunto(s)
Adenocarcinoma , Neoplasias del Colon , Humanos , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/genética , Fluorouracilo/uso terapéutico , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/genética , Receptor de Muerte Celular Programada 1 , Algoritmos , Proteínas de Motivos Tripartitos/genética , Ubiquitina-Proteína Ligasas/genética
5.
Biotechnol Appl Biochem ; 69(1): 160-165, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33369762

RESUMEN

Acute myocardial infarction (AMI) is the heart attack happening when the blood flow is terminated to the heart muscles. C-reactive protein (CRP) level is raising significantly in AMI patients after the onset of symptom; also, temporal variations of CRP in plasma of AMI patient have also been found. Quantifying the concentration of CRP helps to identify the condition associated with AMI. Plasmonic enzyme-linked immunosorbent assay (ELISA) was utilized here to identify CRP by the sandwich of aptamer and antibody. Bare-eye CRP detection was achieved by plasmonic ELISA through the aggregation (blue color) of gold nanoparticle in the presence of CRP, whereas in the absence of CRP, it retains its red color (dispersion). Depending on the catalase presence on the ELISA surface, hydrogen peroxide (H2 O2 ) controls gold growth and differentiates with color changes. To achieve the lowest detection limit of CRP, H2 O2 (200 µM), gold seed (0.2 µM), and streptavidin-catalase (1:500) were found optimal. The detection limit was reached at 0.25 µg/mL, whereas it was 0.5 µg/mL in the CRP-spiked serum. This method of detection system is easier to detect the levels of CRP and helps diagnosing AMI.


Asunto(s)
Cardiopatías , Nanopartículas del Metal , Biomarcadores , Ensayo de Inmunoadsorción Enzimática , Oro , Humanos
6.
BMC Public Health ; 22(1): 2431, 2022 12 27.
Artículo en Inglés | MEDLINE | ID: mdl-36575512

RESUMEN

BACKGROUND: In China, the new TB control model of trinity form had been implemented in all parts, and the comprehensively evaluation to the performances in primary TB control institutions were closely related to the working capacity and quality of TB service, but there was still no an unified evaluation indicators framework in practice and few relevant studies. The purpose of this study was to establish an indicators framework for comprehensively evaluating the performances in primary TB control institutions under the new TB control model of trinity form in Guangxi, China. METHODS: The Delphi method was used to establish an indicators framework for comprehensively evaluating the performances in primary TB control institutions under the new TB control model of trinity form, and the analytic hierarchy process(AHP) was used to determine the weights of all levels of indicators, from September 2021 to December 2021 in Guangxi, China. RESULTS: A total of 14 experts who had at least 10 years working experience and engaged in TB prevention and control and public health management from health committee, CDC, TB designated hospitals and university of Guangxi were consulted in two rounds. The average age of the experts were (43.3 ± 7.549) years old, and the effective recovery rate of the questionnaire was 100.0%. The average value of authority coefficient of experts (Cr) in the two rounds of consultation was above 0.800. The Kendall's harmony coefficient (W) of experts' opinions on the first-level indicators, the second-level indicators and the third-level indicators were 0.786, 0.201 and 0.169, respectively, which were statistically significant (P < 0.05). Finally, an indicators framework was established, which included 2 first-level indicators, 10 second-level indicators and 37 third-level indicators. The results of analytic hierarchy process (AHP) showed that the consistency test of all levels of indicators were CI < 0.10, which indicating that the weight of each indicator was acceptable. CONCLUSION: The indicators framework established in this study was in line with the reality, had reasonable weights, and could provide a scientific evaluation tool for comprehensively evaluating the performances in primary TB control institutions under the new TB control model of trinity form in Guangxi, China.


Asunto(s)
Procesos de Grupo , Hospitales , Humanos , Adulto , Persona de Mediana Edad , Técnica Delphi , China/epidemiología , Encuestas y Cuestionarios
7.
Neurochem Res ; 46(6): 1400-1409, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33738663

RESUMEN

The proliferation and differentiation of Schwann cells are critical for the remyelination of injured peripheral nerve. Ginsenoside compound K (CK) is a metabolite produced from ginsenoside Rb1 which has strong anti-inflammatory effects. However, the potential effects of CK on Schwann cells have not been studied systematically before. Therefore, this study was aimed to explore the functions of CK in Schwann cell proliferation, migration and differentiation and its potential regulatory mechanism. Primary Schwann cells and RSC96 cells were treated with or without CK at different doses. The proliferation and migration of primary Schwann cells and RSC96 cells were examined by Cell Counting Kit-8 (CCK-8) and Transwell assays, respectively. The mRNA expression of myelin-associated glycoprotein (MAG) and myelin basic protein (MBP) was tested by quantitative real-time polymerase chain reaction (qRT-PCR). The levels of all proteins were examined by Western blot. CK could promote cell proliferation, migration and induce MAG and MBP expression in primary Schwann cells and RSC96 cells. Furthermore, CK activated MEK/ERK1/2 and PI3K/AKT pathways, and the beneficial effects of CK on primary Schwann cells and RSC96 cells were distinctly suppressed by inhibitor PD98059 or LY294002. Ginsenoside compound K induced cell proliferation, migration and differentiation via the activation of MEK/ERK1/2 and PI3K/AKT pathways in cultured primary Schwann cells and RSC96 cells.


Asunto(s)
Diferenciación Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Ginsenósidos/farmacología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Células de Schwann/efectos de los fármacos , Animales , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Ratas
8.
Biotechnol Lett ; 43(1): 153-164, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33145670

RESUMEN

OBJECTIVES: Breast cancer is a popular fatal malignant tumor for women with high of rates incidence and mortality. Development of the new approaches for breast cancer targeted diagnosis and chemotherapy is emergently needed by the current clinical practice, the important first step is finding a breast cancer specifically binding molecule or fragment as early clinical indicators. RESULTS: By a phage-displayed peptide library, a 12-mer peptide, CSB1 was screened out using MCF-7 cells as the target. The consequently results under immunofluorescence and laser scanning confocal microscope (LSCM) indicated that CSB1 bound MCF-7 cells and breast cancer tissues specifically and sensitively with high affinity. Bioinformatics analysis suggested that the peptide CSB1 targets the 5-Lipoxygenase-Activating Protein (FLAP), which has been implicated in breast cancer progression and prognosis. CONCLUSIONS: The peptide, CSB1 is of the potential as a candidate to be used for developing the new approaches of molecular imaging detection and targeting chemotherapy of breast cancer in the future.


Asunto(s)
Bioprospección/métodos , Neoplasias de la Mama , Biblioteca de Péptidos , Péptidos , Mama/química , Mama/metabolismo , Neoplasias de la Mama/química , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Femenino , Humanos , Células MCF-7 , Péptidos/análisis , Péptidos/química , Péptidos/metabolismo
9.
Inorg Chem ; 59(19): 14093-14100, 2020 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-32977720

RESUMEN

A new superatom of dual valence states, namely Al7Li, has been proposed to further enrich the "three-dimensional periodic table". It bears great resemblance to group IVA elements in many aspects. Chief among them is that Al7Li favors both +2 and +4 oxidation states, which makes it analogous to the heavier carbon-group elements. Al7Li is capable of forming stable ionic compounds with carbon, oxygen, and fluorine and forming covalent tetrahydride with hydrogen, just as how germanium, tin, and lead atoms combine with these elements to form stable molecules. The nearest atomic counterpart of Al7Li in group IV is probably Sn or Pb since their oxides and tetrahydrides share like characteristics.

10.
Pharm Biol ; 58(1): 352-356, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32298152

RESUMEN

Context: Both nobiletin (NBL) and glycyrrhizin (GL) have anti-inflammatory and antitumor properties. These agents may be co-administered in the clinic. However, the drug-drug interaction between them is not clear.Objective: The drug-drug interaction between GL and NBL was investigated, to clarify the effect of GL on the pharmacokinetics of NBL, and its main mechanism.Materials and methods: The pharmacokinetic profiles of oral administration of NBL (50 mg/kg) in Sprague-Dawley rats of two groups with six each, with or without pre-treatment of GL (100 mg/kg/day for 7 days), were investigated. The effects of GL on the metabolic stability and transport of NBL were also investigated through the rat liver microsome and Caco-2 cell transwell models.Results: The results showed that GL significantly decreased the peak plasma concentration (from 1.74 ± 0.15 to 1.12 ± 0.10 µg/mL) and the t1/2 (7.44 ± 0.65 vs. 5.92 ± 0.68) of NBL, and the intrinsic clearance rate of NBL was increased by the pre-treatment with GL (39.49 ± 2.5 vs. 48.29 ± 3.4 µL/min/mg protein). The Caco-2 cell transwell experiments indicated that GL could increase the efflux ratio of NBL from 1.61 to 2.41.Discussion and conclusion: These results indicated that GL could change the pharmacokinetic profile of NBL, via increasing the metabolism and efflux of NBL in rats. It also suggested that the dose of NBL should be adjusted when co-administrated with GL in the clinic.


Asunto(s)
Antiinflamatorios/farmacología , Antineoplásicos/farmacocinética , Flavonas/farmacocinética , Ácido Glicirrínico/farmacología , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Administración Oral , Animales , Antiinflamatorios/administración & dosificación , Antineoplásicos/administración & dosificación , Transporte Biológico/efectos de los fármacos , Células CACO-2 , Citocromo P-450 CYP3A/metabolismo , Interacciones Farmacológicas , Medicamentos Herbarios Chinos , Flavonas/administración & dosificación , Ácido Glicirrínico/administración & dosificación , Humanos , Masculino , Tasa de Depuración Metabólica/efectos de los fármacos , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Ratas , Ratas Sprague-Dawley
11.
Nanotechnology ; 30(7): 075604, 2019 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-30523991

RESUMEN

'Targeting peptides' have demonstrated their value in diagnostic imaging and therapy and novel peptide probes specific to cervical cancer were developed. In the M13KE phage dodecapeptide (12-mer) peptide library, the phage clone S7 showed the best binding to the cancer cells as confirmed by immunofluorescence and flow cytometry assays, and was selected for continued studies. Its binding peptide, CSP3, was synthesized from the sequence of S7's 12-mer at the N-terminus of the minor coat protein pIII of this M13KE phage vector. The peptide's binding was analyzed by the same assays used for S7. It was also assessed using competitive inhibition and binding to a tissue chip. The results demonstrated that the CSP3 peptide bound to cervical carcinoma cells with high sensitivity and specificity. The positive results indicated that the peptide CSP3, conjugated with nanomaterials and chemotherapeutics, may be developed as a targeting vehicle for therapeutic drug delivery against cervical cancer, especially cervical cancer with multiple drug resistance. For this aim, we prepared a CSP3 conjugated liposome drug delivery system containing doxorubicin (DOX) and microRNA101 (miR101) expression plasmids (CSP3-Lipo-DOX-miR101), and the primary result showed that the system demonstrated significantly enhanced cytotoxicity to SiHa cells and DOX resistant SiHa cells, SiHa/ADR. Our results showed that CSP3 is a cervical cancer targeting 12aa peptide with high specificity and sensitivity, and the CSP3 conjugated drug delivery system, CSP3-Lipo-DOX-miR101 has promising potential for development as an efficient drug system for the therapy of cervical cancer.


Asunto(s)
Doxorrubicina/análogos & derivados , MicroARNs/farmacología , Péptidos/metabolismo , Neoplasias del Cuello Uterino/metabolismo , Adulto , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/química , Doxorrubicina/farmacología , Sistemas de Liberación de Medicamentos , Femenino , Humanos , MicroARNs/química , Persona de Mediana Edad , Biblioteca de Péptidos , Péptidos/química , Péptidos/aislamiento & purificación , Polietilenglicoles/química , Polietilenglicoles/farmacología , Neoplasias del Cuello Uterino/terapia
12.
Microsc Microanal ; 25(4): 950-960, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31172894

RESUMEN

Annexin A2 (ANXA2) is reported to be associated with cancer development. To investigate the roles ANXA2 plays during the development of cancer, the RNAi method was used to inhibit the ANXA2 expression in caco2 (human colorectal cancer cell line) and SMMC7721 (human hepatocarcinoma cell line) cells. The results showed that when the expression of ANXA2 was efficiently inhibited, the growth and motility of both cell lines were significantly decreased, and the development of the motility relevant microstructures, such as pseudopodia, filopodia, and the polymerization of microfilaments and microtubules were obviously inhibited. The cancer cell apoptosis was enhanced without obvious significance. The possible regulating pathway in the process was also predicted and discussed. Our results suggested that ANXA2 plays important roles in maintaining the malignancy of colorectal and hepatic cancer by enhancing the cell proliferation, motility, and development of the motility associated microstructures of cancer cells based on a possible complicated signal pathway.


Asunto(s)
Anexina A2/metabolismo , Carcinogénesis , Carcinoma Hepatocelular/fisiopatología , Neoplasias Colorrectales/fisiopatología , Citoesqueleto/metabolismo , Neoplasias Hepáticas/fisiopatología , Anexina A2/genética , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Silenciador del Gen , Humanos , Modelos Biológicos , Interferencia de ARN
13.
BMC Med Educ ; 19(1): 367, 2019 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-31597576

RESUMEN

BACKGROUND: Information and communications technology (ICT) has been suggested as an important tool for improving global health education and building research capacity in developing countries. However, the existing curricula do not have adequate emphasis on global health research and training. This study was carried out to examine health sciences postgraduates' attitudes and practices regarding curriculum for ICT use in global health research and training in China. METHODS: A cross-sectional study was conducted among health sciences postgraduates from six universities in southern China, during December 2016 to March 2017. A self-administered online questionnaire was used to collect data through an online survey platform. Data were analyzed using SPSS for Windows 13.0. RESULTS: A total of 1065 participants successfully completed the questionnaires. More than 90% of the students have not had any training about ICT, three quarters have not taken an online course, and 31% of the students do not use ICT in their current research. More than 65% thought that, in an ICT research training curriculum, it was important to learn: ICT utilization related knowledge, ICT research methods/resources, knowledge of databases, ways of data use and acquisition, and informatics search methods (ICT users compared to non-users were more likely to agree to these learning components (all p <  0.05)). Many of the respondents used or planned to use mobile phones (80%), Internet (59%), use computer and WeChat (> 40%), and QQ (a popular chat tool in China) (30%) as ICT tools in research activities. ICT users compared to non-users were more likely to consider using ICT and/or biomedical informatics methods in decision-support or support for information seeking, healthcare delivering, academic research, data gathering, and facilitating collaboration (all p <  0.05). CONCLUSIONS: The findings of this study showed that ICT utilization was very important to health sciences postgraduates for their research activities in China, but they lacked ICT-related training. The results suggested the need for specialized curriculum related to ICT use in global health research for health sciences postgraduates in China.


Asunto(s)
Investigación Biomédica/educación , Salud Global/educación , Estudiantes del Área de la Salud/psicología , Universidades , Adulto , China , Estudios Transversales , Curriculum , Femenino , Humanos , Tecnología de la Información , Masculino , Informática Médica , Adulto Joven
14.
Health Res Policy Syst ; 15(1): 59, 2017 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-28659155

RESUMEN

BACKGROUND: The demand to use information and communications technology (ICT) in education and research has grown fast among researchers and educators working in global health. However, access to ICT resources and the capacity to use them in global health research remains limited among developing country faculty members. In order to address the global health needs and to design an ICT-related training course, we herein explored the Chinese health science faculty members' perceptions and learning needs for ICT use. METHODS: Nine focus groups discussions (FGDs) were conducted during December 2015 to March 2016, involving 63 faculty members working in areas of health sciences from six universities in China. All FGDs were audio recorded and analysed thematically. RESULTS: The findings suggest that the understandings of ICT were not clear among many researchers; some thought that the concept of ICT was too wide and ambiguous. Most participants were able to cite examples of ICT application in their research and teaching activities. Positive attitudes and high needs of ICT use and training were common among most participants. Recommendations for ICT training included customised training programmes focusing on a specific specialty, maintaining a balance between theories and practical applications, more emphasis on the application of ICT, and skills in finding the required information from the bulk information available in the internet. Suggestions regarding the format and offering of training included short training programmes, flexible timing, lectures with practicum opportunities, and free of charge or with very minimal cost to the participants. Two participants suggested the linking of ICT-related training courses with faculty members' year-end assessment and promotion. CONCLUSIONS: This study among health sciences faculty members in China demonstrated a high level of need and interest in learning about ICT use in research and training. The results have important implications for the design and implementation of ICT-related educational programmes in China and other developing countries.


Asunto(s)
Creación de Capacidad , Comunicación , Salud Global , Invenciones , China , Docentes , Humanos , Investigación Cualitativa , Investigadores
15.
Chemphyschem ; 17(17): 2672-8, 2016 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-27219640

RESUMEN

Guided by density functional theory (DFT) computations, a new series of superalkali-based alkalides, namely FLi2 (+) (aza222)K(-) , OLi3 (+) (aza222)K(-) , NLi4 (+) (aza222)K(-) , and Li3 (+) (aza222)K(-) were designed with various superalkali clusters embedded into an aza222 cage-complexant. These species possess diverse isomeric structures in which the encapsulated superalkalis preserve their identities and behave as alkali metal atoms. The results show that these novel alkalides possess larger complexation energies and enhanced hyperpolarizabilities (ß0 ) compared with alkali-metal-based and previous superalkali-based clusters. Especially, a prominent structural dependence of ß0 is observed for these studied compounds. Hence, the geometric factors that affect the nonlinear optical (NLO) response of such alkalides is elucidated in detail in this work. This study not only provides novel candidates for alkalides, it also offers an effective way to enhance the NLO response and stability of alkalides.

16.
Phys Chem Chem Phys ; 17(6): 4524-32, 2015 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-25583355

RESUMEN

On the basis of stable alkaline earth metal ammines, a series of M(NH3)6NaCl and M(NH3)6Na2 (M = Mg and Ca) excess electron compounds were theoretically constructed and studied by using the density functional theory. The electride or alkalide characteristics of these compounds are verified by their electronic structures, HOMOs, and small VIE values. It is worth noting that the M(NH3)6Na2 alkalides have novel electronic structures that contain double alkali metal anions. As expected, all the noncentrosymmetric M(NH3)6NaCl and M(NH3)6Na2 compounds possess considerable first hyperpolarizabilities (ß0) up to 123 050 au, which can be attributed to low excitation energies (ΔEs) and large oscillator strength (f0) of their crucial excited states. In addition, results reveal that the Ca(NH3)6-based species with lower ΔEs and larger transition moments (Δµ) show larger ß0 values compared with the corresponding Mg(NH3)6-based ones with similar geometries. This study may be significant in terms of designing excess electron compounds of new-type, especially alkalides with multiple alkali metal anions.

17.
J Phys Chem A ; 119(10): 2083-90, 2015 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-25695357

RESUMEN

Modulation of intermolecular interactions in response to external electric fields could be fundamental to the formation of unusual forms of water, such as water whiskers. However, a detailed understanding of the nature of intermolecular interactions in such systems is lacking. In this paper, we present novel theoretical results based on electron correlation calculations regarding the nature of H-bonds in water whiskers, which is revealed by studying their evolution under external electric fields with various field strengths. We find that the water whiskers consisting of 2-7 water molecules all have a chain-length dependent critical electric field. Under the critical electric field, the most compact chain structures are obtained, featuring very strong H-bonds, herein referred to as covalent H-bonds. In the case of a water dimer whisker, the bond length of the novel covalent H-bond shortens by 25%, the covalent bond order increases by 9 times, and accordingly the H-bond energy is strengthened by 5 times compared to the normal H-bond in a (H2O)2 cluster. Below the critical electric field, it is observed that, with increasing field strength, H-bonding orbitals display gradual evolutions in the orbital energy, orbital ordering, and orbital nature (i.e., from typical π-style orbital to unusual σ-style double H-bonding orbital). We also show that, beyond the critical electric field, a single water whisker may disintegrate to form a loosely bound zwitterionic chain due to a relay-style proton transfer, whereas two water whiskers may undergo intermolecular cross-linking to form a quasi-two-dimensional water network. Overall, these results help shed new insight on the effects of electric fields on water whisker formation.

18.
Biomed Chromatogr ; 29(3): 396-401, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25042110

RESUMEN

A novel method for the direct determination of kanamycin B in the presence of kanamycin A in fermentation broth using high performance liquid chromatography with evaporative light scattering detector (HPLC-ELSD) was developed. An Agilent Technologies C18 column was utilized, evaporation temperature of 40°C and nitrogen pressure of 3.5 bar, the optimized mobile phase was water-acetonitrile (65:35, v/v), containing 11.6 mm heptafluorobutyric acid (isocratic elution with flow rate of 0.5 mL/min) with the gain 11. Kanamycin B was eluted at 5.6 min with an asymmetry factor of 1.827. The method showed good linearity over the concentration range of 0.05 to 0.80 mg/mL for the kanamycin B (r(2) = 0.9987). The intra-day and inter-day coefficients of variation obtained from kanamycin B were less than 4.3%. Mean recovery of kanamycin B from spiked fermentation broth was 95%. The developed method was applied to the determination of kanamycin B without any interference from other constituents in the fermentation broth. This method offers simple, rapid and quantitative detection of kanamycin B.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Kanamicina/análogos & derivados , Dispersión de Radiación , Calibración , Fraccionamiento Químico/métodos , Cromatografía Líquida de Alta Presión/instrumentación , Medios de Cultivo/análisis , Medios de Cultivo/química , Estabilidad de Medicamentos , Fermentación , Kanamicina/análisis , Kanamicina/aislamiento & purificación , Luz , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Temperatura
19.
J Cell Physiol ; 229(3): 287-91, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23939989

RESUMEN

Numerous evidences have indicated that a signal system is composed by signal pathways, each pathway is composed by sub-pathways, and the sub-pathway is composed by the original signal terminals initiated with a protein/gene. We infer the terminal signals merged signal transduction system as "signal basin". In this article, we discussed the composition and regulation of signal basins, and the relationship between the signal basin control and triple W of spatiotemporal cell biology. Finally, we evaluated the importance of the systemic regulation to gene expression by signal basins under triple W. We hope our discussion will be the beginning to cause the attention for this area from the scientists of life science.


Asunto(s)
Biología Celular , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Transducción de Señal , Biología de Sistemas , Animales , Regulación de la Expresión Génica , Redes Reguladoras de Genes , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Modelos Biológicos , Transducción de Señal/genética
20.
Front Psychol ; 15: 1349002, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38445055

RESUMEN

It is evident that sarcasm can be interpreted differently due to various factors, However, rare research was conducted to investigate the influence of national culture on sarcasm comprehension despite its valuable theoretical implication. This study used an online rating task to explore how national culture impacts the comprehension of sarcasm, focusing on the differences between Chinese and American cultural values (i.e., power distance, uncertainty avoidance, collectivism, long-term orientation, and masculinity) and their influence on comprehending sarcastic praise and criticism. The study showed that Chinese participants tend to understand sarcasm less than Americans. It also found that Power Distance is linked to better sarcasm comprehension in both cultures, while Uncertainty Avoidance has a negative effect on it, especially in Chinese participants. Collectivism is also associated with improved sarcasm comprehension, especially in Chinese participants. However, Masculinity and Long-Term Orientation do not seem to have a significant impact on sarcasm comprehension, regardless of nationality or the type of comment (praise or criticism). Overall, the study reveals nuanced differences in how cultural values shape the comprehension of sarcasm in Chinese and American contexts, underscoring the complex interplay between culture and communication.

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