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1.
J Technol Transf ; : 1-26, 2023 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-37359818

RESUMO

This paper focuses on institutional influences on innovation efficiency across countries. Whereas various causes and effects of technological change have been examined, empirical investigations of the efficiency involved in innovation production are relatively few. Using data on a large sample of nations over 2018-2020 and considering corruption, regulatory quality, and state fragility as alternative institutional dimensions, our results show that greater corruption facilitates ("greases") efficiency in the production of innovations. This is also the case with improvements in regulatory quality, while greater state fragility increases inefficiency. These findings for the overall sample are somewhat different for the OECD and non-OECD subsamples, although the greasing effect of corruption remains throughout. A robustness check with patent protection and government size as alternative institutional dimensions is also conducted.

2.
Artigo em Inglês | MEDLINE | ID: mdl-36247212

RESUMO

Using recent data on the unvaccinated population across US states, this paper focuses on the determinants of vaccine hesitancy related to the COVID-19 pandemic. Findings show that more prosperous states and states with more elderly residents and more physicians have lower vaccine hesitancy. There was some evidence of the significance of race, but internet access and history of other contagious diseases failed to make a difference. States with centralized health systems and those with mask mandates generally had a lower percentage of unvaccinated populations. Finally, the presence of Democrats in state legislatures tended to lower vaccination hesitancies, ceteris paribus.

3.
MDE Manage Decis Econ ; 43(6): 2578-2586, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35465149

RESUMO

The increasing use of vaccine passports (VPs) to certify immunity from the prevailing coronavirus has created positive and negative aspects that have shaken the workings of markets. The VPs are, however, not universally used and not required by all businesses and governments at this point. Given the newness associated with VPs and the ongoing uncertainty of the pandemic, full implications of VPs have not been considered. This paper provides some formal insights into the implications of the use of VPs, borrowing from the established economic theory. Recommendations for public policy are provided.

4.
Environ Monit Assess ; 194(5): 389, 2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35445887

RESUMO

Prediction of influent characteristics, before any treatment takes place, is of great importance to the operation and management of wastewater treatment plants (WWTPs). In this study, four machine-learning models, including multilayer perceptron (MLP), long short-term memory network (LSTM), K-nearest neighbour (KNN), and random forest (RF), are introduced to utilize real-time wastewater data from three WWTPs in North America (i.e., Tres Rios, Woodward, and one confidential plant) for predicting hourly influent characteristics. Input variables are selected using an autocorrelation analysis and a variable importance measure from RF. Both univariate and multivariate analyses are investigated to improve model accuracy. The performances of one- and multiple-step-ahead models are compared. With a short prediction horizon, all the models derived from both univariate and multivariate analyses show excellent performance. It was found that the performance deterioration as the prediction horizon expands could be mitigated significantly by including extra variables, such as meteorological variables. This work can provide valuable support for the high-temporal-resolution prediction of wastewater influent characteristics for WWTPs. The proposed models can also bridge the gap between data and decision-making in the wastewater sector.


Assuntos
Águas Residuárias , Purificação da Água , Monitoramento Ambiental , Aprendizado de Máquina , Redes Neurais de Computação
5.
Soc Sci Med ; 301: 114958, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35413528

RESUMO

Corruption is considered in the literature as an activity with several externalities and spillover effects. Adding to the recent research on the corruption-COVID-19 nexus, we study the impact of corruption on coronavirus cases. High perceived levels of corruption have been proven to lead to lower institutional trust, and hence possibly to lower levels of citizen compliance with non-pharmaceutical interventions (NPIs), such as lockdowns, imposed by the authorities during the first wave of the pandemic to reduce the spread of coronavirus. Applying quantitative analysis with the use of hybrid models, we find that in countries with higher levels of perceived corruption, across alternative corruption measures, more COVID-19 cases are observed, ceteris paribus. This suggests that corruption has a detrimental effect on the spread of COVID-19, and that countries experiencing higher levels of corruption should pay extra attention when implementing NPIs.


Assuntos
COVID-19 , Controle de Doenças Transmissíveis , Humanos , Pandemias/prevenção & controle , SARS-CoV-2
6.
Water Sci Technol ; 85(2): 617-632, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35100143

RESUMO

Sludge retention time (SRT) regulation is one of the essential management techniques for refined control of the main-sidestream treatment process under the low ammonia density. It is indispensable to understand the effect of SRTs changes on the Nitrifier kinetics to obtain the functional separation of the Nitrifier and the refined control of the nitrification process. In this study, Nitrifier was cultured with conditions of 35 ± 0.5 °C, pH 7.5 ± 0.2, DO 5.0 ± 0.5 mg-O/L, and SRTs were controlled for 40 d, 20 d, 10 d, and 5 d. The net growth rate (µm), decay rate (b), specific growth rate (µ), the yield of the Nitrifier (YA), temperature parameter (TA), and inhibition coefficient (KI) have been measured and extended with the SRT decreases. Instead, the half-saturation coefficient (KS) decreased. In addition, the limited value of pH inhibition occurs (pHUL), and the pH of keeping 5% maximum reaction rate (pHLL) was in a relatively stable state. The trade of kinetics may be induced by the change of species structure of Nitrifier. The Nitrosomonas proportion was increased, and the Nitrospira was contrary with the SRT decreasing. It is a match for the functional separation of Nitrifier when SRTs was 20 d at ambient temperature under the low ammonia density. The kinetics of ammonia-oxidizing organisms (AOO) and nitrite-oxidizing organisms (NOO) in Nitrifier under different SRT conditions should be measured respectively to the refined control of the partial nitrification process in future study.


Assuntos
Amônia , Esgotos , Reatores Biológicos , Cinética , Temperatura
7.
Contemp Econ Policy ; 40(2): 263-282, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34898973

RESUMO

This article studies the impact of disease epidemics on the worldwide prevalence of the shadow or the underground economy. The informal sector has low entry barriers and provides an easy short-term option for the supply of goods and services during epidemics when traditional supply lines are cut or strained. Furthermore, the enforcement resources might be directed elsewhere during epidemics, lowering the expected costs of shadow operations. Using data for over 125 nations, we find that the incidence of epidemics positively and significantly contributes to the spread of the underground sector. These findings withstand a series of robustness checks.

8.
Metroeconomica ; 72(3): 580-591, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34226764

RESUMO

This paper analytically examines the demand for surgical masks following the recent health precautions due to coronavirus. Using a simple linear demand curve and alternatively examining the impacts of requirements that mandate (a) the wearing of masks by frontline workers; (b) suggested but not required masking by the whole public; and (c) compulsory masking by the whole public. The impacts of the different scenarios on the price elasticity of demand are determined along with the slope (or the rate of change) of elasticity. Some of these results differ when a non-linear demand curve is considered instead. The equilibrium mask prices increase when masks are universally mandated, whereas the consumer surplus is higher when masks are recommended but not mandated. However, the ranking of consumer surplus is shown to be sensitive to the supply elasticity of masks. These considerations enable a structured means to view the demand implications of masking requirements and provide some food for policy thought.

9.
Water Environ Res ; 93(10): 2084-2096, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33991363

RESUMO

Anaerobic digestion (AD) is a biological treatment process to stabilize organic solids and produce biogas. If present, sulfate is reduced to sulfide by anaerobic sulfate-reducing bacteria and the sulfide can be toxic to anaerobic microorganisms. Here, the effect of high initial sulfate concentration on AD of wastewater sludge was investigated using lab-scale batch experiments. Additionally, a systematic mathematical modeling approach was applied for insight into the experimental results. Cumulative biogas and methane production decreased with increasing initial sulfate doses (0-3.300 mg S L-1 ). The correlation between the sulfate dose and methane production was consistent with theoretical predictions and model results, indicating no toxic effect of sulfide on methane production. The carbon dioxide content in the biogas decreased linearly with the increasing sulfate dose, which is consistent with the model-predicted behavior of the bicarbonate and hydrogen sulfide buffering system. The examined high sulfate concentrations resulted in no clear negative effects on the COD removal or VSS destruction of the wastewater sludge, indicating negligible inhibition by sulfide toxicity. Even considering the possibility of ferrous sulfide precipitation and the low model estimates of residual sulfide concentration the residual sulfide concentration was higher than reported concentrations that trigger process inhibition. PRACTITIONER POINTS: The effect of sulfate loading on anaerobic digestion of waste activated sludge was characterized. The stoichiometry of sulfate reduction allows accurate prediction of CH4  loss. High sulfate levels (up to 3300 mg/L as S) did not affect COD/VSS removal. Sulfide formation increases effluent COD; often misinterpreted as sulfide toxicity. Correcting COD for sulfide's contributions is crucial for results interpretation.


Assuntos
Esgotos , Águas Residuárias , Anaerobiose , Reatores Biológicos , Metano , Sulfatos , Eliminação de Resíduos Líquidos
10.
J Policy Model ; 43(3): 503-520, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33967361

RESUMO

The sanctioning of different coronavirus vaccines (with some approved by regulators for public delivery, and others in the pipeline) has met with relief by many sections of the public and the government. However, partly due to the damages associated with the pandemic and the ensuing euphoria over vaccines' arrival, some of the challenges are mostly being ignored or are not recognized. This paper identifies some pitfalls and drawbacks in vaccine delivery. We argue that the somewhat unique tension between the speed of vaccine delivery and its scale can create opportunities for corrupt behavior that are often at odds with effective means to check abuse. While data on instances of abuse will emerge over time, it is useful to point out different avenues of abuse so that some preventive government actions can be undertaken. Specifically, we argue that the potential for out of turn delivery of vaccines and the stockpiling by unauthorized agents creates incentives for corruption, with the public or bureaucrats initiating corrupt transactions. An understanding of the potential avenues for corruption should guide the formulation of appropriate corruption-control policies and similar challenges that will be faced by policy makers in addressing future pandemics.

11.
Water Sci Technol ; 82(2): 273-280, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32941169

RESUMO

The objective of this study is to explore the optimal pre-treatment procedures and statistics methods for live/dead bacterial staining using nitrite oxidizing organism (NOO) as the research aim. This staining method was developed and widely utilized to evaluate activated bacterial survival situation, because it is direct and convenience to count live and dead bacteria amount by colour distinguishes (green/red) from pictures taken by microscope. The living cell (green colour) percentage and initial bacterial chemical oxygen demand (COD) could be used for accurate reaction rate calculation at the beginning of tests. While according to the physiological principles, the detection target was limited as the organism has a complete cell shape, that was applicable for the initial phase for decay stage (live cell → particulate dead cell), but it is impossible to evaluate the decayed soluble COD from particulate dead cell during whole reaction. To model the decay stage scientifically, a two-step decay model was developed to cater to the live/dead bacterial staining analysis of biological nitrite oxidizer under inhibition condition of high nitrite concentrations at 35 °C. As results of optimal pre-treatment, a three level ultrasonic wave with 45 seconds was explored, as a reasonable observed picture number, 30 sets with 95% confident interval for datasets statistics was summarized. A set of nitrite oxidizer inhibition test (total COD and oxygen uptake rates) under high nitrite concentrations was simulated using the above model and obtained experimental schemes. Additionally, the disintegration enhancement from particulate dead cell to soluble COD by nitrite was inspected and modelled on the basis of experimental datasets.


Assuntos
Nitritos , Esgotos , Bactérias , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Oxirredução
12.
Water Res ; 179: 115883, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32402863

RESUMO

Acidic failure is relatively common in anaerobic digesters that receive readily biodegradable food wastes at high loading. Under low pH conditions, the activity of methanogenic biomass decreases resulting in complete failure of the digestion process. In this experimental study, we demonstrated that one of the causes for the digester failure under low pH conditions is due to accelerated decay of methanogenic biomass. When enriched acetate degrading methanogens were exposed to a low pH environment (pH = 5.1 with phosphoric acid) in a batch experiment without external substrate, the specific decay rate was observed to increase as much as 10 times of that at pH 7.0. The specific decay rate for formate degrader was also found to increase under low pH conditions whilst the fermentative microorganisms in the cultures appeared to be tolerant to low pH conditions. A Propidium Mono-Azide-quantitative Polymerase Chain Reaction (PMA-qPCR) analysis revealed that the archaeal biomass dominated by methanogens dropped by 71-79% from the initial concentration after 6 days of the acidic batch experiment whilst the bacterial biomass dominating acidogens decreased by only 25%. The decrease in the number of living cells in the batch experiments at different pH was monitored with time to determine a correlation between decay rate and incubation pH.


Assuntos
Euryarchaeota , Anaerobiose , Archaea , Biomassa , Reatores Biológicos , Concentração de Íons de Hidrogênio , Metano
13.
Burns ; 46(5): 1157-1169, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-31870570

RESUMO

Radiation induced skin wound/dermatitis is one of the common side effects of radiotherapy or interventional radiobiology. In order to combat impaired healing of radiation wounds, alternative therapy to use sildenafil citrate (SC) topical hydrogel as a therapeutic option was proposed that has known to enhance nitric oxide in wounds. Our aim was to develop a radiation induced skin wound model and to investigate the wound healing efficacy of 5% SC hydrogel formulation in Sprague-Dawley rats. In the present study, the radiation wound inducing dose was optimized using a multi-dose localized γ-radiation trail with 10-55Gy range (15Gy interval). Optimal irradiation dose for wound induction was selected based on radiation skin damage assessment criteria followed the relative change from <35Gy or>55Gy showed significant variation and median 45Gy γ-dose was selected for studying acute effects of radiation on wound healing. Significant (p<0.05) higher wound contraction (88±1.02%), skin damage reduction (81±0.82%), tensile strength (45±1.61%), nitric oxide and protein recovery (53±0.72%) at dermal level prove the wound healing efficacy of 5% SC hydrogel formulation as compared to Rad 45Gy control. In addition, the dose modifying factor (DMF) for SC hydrogel treatment was found to be 1.83 and 1.57 with respect to total wound area contraction and skin damage reduction. Skin histopathology in treated tissues showed improved granulation tissue formation, less inflammatory infiltrates and mature collagen fibres in the dermis. Thus, the modality could help to improve delayed wound healing in irradiated skin tissues.


Assuntos
Hidrogéis/farmacologia , Inibidores da Fosfodiesterase 5/farmacologia , Radiodermite , Reepitelização/efeitos dos fármacos , Citrato de Sildenafila/farmacologia , Pele/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Raios gama/efeitos adversos , Óxido Nítrico/metabolismo , Ratos , Pele/metabolismo , Pele/patologia , Pele/efeitos da radiação
14.
Water Sci Technol ; 77(11-12): 2812-2822, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30065133

RESUMO

High nitrite is a known operation parameter to inhibit the biological oxidation of nitrite to nitrate. The phenomenon is traditionally expressed using a Monod-type equation with non-competitive inhibition, in which the reaction associated with the biomass growth is reduced when high nitrite is present. On the other hand, very high nitrite is also known to slay nitrifiers. To clarify the difference between the growth inhibition and the poisoning, cell counting for living microorganisms in the nitrite oxidiser-enriched activated sludge was conducted in batch conditions under various nitrite concentrations together with measurements of biomass chemical oxygen demand (COD) concentration and oxygen uptake rate. The experiments demonstrated that these measureable parameters were all decayed when nitrite concentration exceeded 100-500 mgN/L at pH 7.0 in the system, indicating that nitrite poisoning took place. Biomass growth was recognised in lower range of nitrite which was expressed with growth inhibition only. Based on the response, a kinetic model for the biological nitrite oxidation was developed with a modification of IWA ASM1. The model was further utilised to calculate a possibility to wash out nitrite oxidiser in the aeration tank where a part of the return activated sludge was exposed to high nitrite liquor in a side-stream partial nitritation reactor.


Assuntos
Reatores Biológicos/microbiologia , Consórcios Microbianos/fisiologia , Nitritos/metabolismo , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/instrumentação , Análise da Demanda Biológica de Oxigênio , Biomassa , Concentração de Íons de Hidrogênio , Consórcios Microbianos/efeitos dos fármacos , Nitratos/metabolismo , Nitritos/farmacologia , Oxirredução , Eliminação de Resíduos Líquidos/métodos
15.
Water Sci Technol ; 77(11-12): 2876-2885, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30065140

RESUMO

Allylthiourea is a known specific inhibitor for ammonium oxidiser to suppress its oxygen uptake, and is commonly used for various kinds of batch respirometric tests to detect heterotrophic respiration in activated sludge. However, when high heterotrophs were present in the sample, it appeared the inhibitor was noticeably degraded and reached below the inhibition threshold after a couple of days, which resulted in overestimation of the heterotrophic respiration. The biological decomposition of the inhibitor was expressed with a Monod-type rate expression having a half-saturation coefficient of 980 mg-COD/L and maximum specific growth rate of 1.0 d-1. The developed kinetic model, including the growth and decay of the heterotrophs and nitrifiers, indicated that the ATU with about 90 mg-ATU/L which was initially dosed to the system would reach below the inhibition threshold of 1.0 mg-ATU/L after 10 days when 750 mg-COD/L of heterotrophs were present. From the kinetic model, an empirical formula to calculate a safe minimum ATU dose for the batch respirometric test was elaborated. The model also provided a modified experimental procedure to accurately estimate the initial heterotrophic biomass concentration in the sample and its specific decay rate based on IWA Activated Sludge Models.


Assuntos
Esgotos/microbiologia , Tioureia/análogos & derivados , Análise da Demanda Biológica de Oxigênio , Biomassa , Reatores Biológicos , Processos Heterotróficos , Cinética , Modelos Teóricos , Nitrificação , Oxigênio/análise , Tioureia/administração & dosagem , Tioureia/química , Tioureia/metabolismo , Eliminação de Resíduos Líquidos/instrumentação , Eliminação de Resíduos Líquidos/métodos
16.
Luminescence ; 32(7): 1252-1262, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28512990

RESUMO

Chalcones possess various biological properties, for example, antimicrobial, anti-inflammatory, analgesic, antimalarial, anticancer, antiprotozoal and antitubercular activity. In this study, naphthylchalcone derivatives were synthesized and characterized using 1 H NMR 13 C NMR, Fourier transform infrared and mass techniques. Yields for all derivatives were found to be >90%. Protein-drug interactions influence the absorption, distribution, metabolism and excretion (ADME) properties of a drug. Therefore, to establish whether the synthesized naphthylchalcone derivatives can be used as drugs, their binding interaction toward a serum protein (bovine serum albumin) was investigated using fluorescence, circular dichroism and molecular docking techniques under physiological conditions. Fluorescence quenching of the protein in the presence of naphthylchalcone derivatives, and other derived parameters such as association constants, number of binding sites and static quenching involving confirmed non-covalent binding interactions in the protein-ligand complex were observed. Circular dichroism clearly showed changes in the secondary structure of the protein in the presence of naphthylchalcones, indicating binding between the derivatives and the serum protein. Molecular modelling further confirmed the binding mode of naphthylchalcone derivatives in bovine serum albumin. A site-specific molecular docking study of naphthylchalcone derivatives with serum albumin showed that binding took place primarily in the aromatic low helix and then in subdomain II. The dominance of hydrophobic, hydrophilic and hydrogen bonding was clearly visible and was responsible for stabilization of the complex.


Assuntos
Chalconas/química , Chalconas/metabolismo , Soroalbumina Bovina/química , Soroalbumina Bovina/metabolismo , Sítios de Ligação , Chalconas/farmacocinética , Dicroísmo Circular , Simulação por Computador , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Simulação de Acoplamento Molecular , Naftóis/química , Estrutura Secundária de Proteína , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Biomed Pharmacother ; 87: 92-101, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28049097

RESUMO

BACKGROUND: Rheumatoid arthritis (RA), an autoimmune inflammatory disorder with synovial hyperplasia, destruction of cartilage, bone damage is often associated with risk of infections. Such risk could be attributed towards usage of immunosuppressive agents. Thus, the present study was undertaken to evaluate the anti-arthritic efficacy of aquo-alcoholic extract of Camellia sinensis (L.). MATERIAL AND METHODS: Dried leaves of Camellia sinensis (L.) or Cs were filtered and extracted in 1:1 aqueous: ethanol by Soxhlet apparatus followed by lyophilization and spray drying to develop amorphous powder. Four different oral doses (50, 100, 200, 400mg/kg/body wt.) of aquo-alcoholic extract were evaluated for anti-edematogenic effect in collagen induced arthritis model. The selected anti-arthritic doses of Cs were evaluated for the oxidative stress markers like Glutathione [5-5'dithio-bis-2-nitrobenzoicacid (DTNB)], Superoxide dismutase [Epinephrine], Catalase [Hydrogen peroxide], Lipid peroxidation [Thiobarbituric acid reactive substance (TBARS)], Nitric oxide [Griess reagents:Nitrobluetetrazolium], Articular elastase [N-methoxysuccinyl-Ala-Ala-Pro- Val p-nitroanilide] in joints followed by haematological evaluation including RBC, WBC, Haemoglobin, platelets and haematocrit. To validate these biochemical changes, the radiological and histopathological (Haematoxylin & Eosin) evaluation was also conducted. RESULTS: The selected anti-arthritic dose of Cs i.e. 400mg/kg/body wt. (∼60% anti-arthritic efficacy on 35th day) could be attributed towards significant (p<0.05) increase in the levels of enzymatic (Superoxide dismutase and Catalase) and non-enzymatic (Glutathione) antioxidants by 34%, 59% and 50% respectively. Simultaneously, the significant (p<0.05) reduction of lipid peroxides, nitrite radical and elastase activity by 32%, 45% & 32% respectively as compare to control indicated overall decrease in oxidative stress. Haematological evaluation revealed restoration of RBC, WBC and platelets level in treatment group. The confirmatory analysis utilizing radiological and histological assessment showed alleviation of joint deformity, tissue swelling, pannus formation and neutrophils infiltration in treatment group as compared to collagen induced arthritis. CONCLUSION: The analysis showed that Cs can play an effective role in reduction of oxidative stress by modulating levels of antioxidants, reducing levels of free radicals while restoring normal haematopoietic cascade as observed in collagen induced arthritis model. Thus, the cumulative dose impact of 400mg/kg body wt., over a period of 14days also found extremely effective in terms of safeguarding their structural conformity against such auto-immune disorder.


Assuntos
Antirreumáticos/uso terapêutico , Artrite Experimental/tratamento farmacológico , Artrite Experimental/patologia , Camellia sinensis , Extratos Vegetais/uso terapêutico , Animais , Antirreumáticos/isolamento & purificação , Feminino , Extratos Vegetais/isolamento & purificação , Folhas de Planta , Ratos , Ratos Wistar , Resultado do Tratamento
18.
Life Sci ; 168: 65-76, 2017 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-27863957

RESUMO

AIMS: p-tertbutylcalix[4]arene loaded nanoemulsion has been designed, characterized and evaluated for skin decontamination of radionuclides of interest in nuclear and radiological emergencies. Further, nanoemulsion was evaluated for Ex-vivo complexation, skin permeation, interaction and cytodermal toxicity. MATERIALS AND METHODS: Ex-vivo skin complexation studies were conducted using High-resolution sector field inductively coupled plasma mass spectroscopy (HR-SF-ICPMS). Skin studies at dermal and cyto-dermal level have been carried out using techniques such as florescence microscopy, Differential scanning calorimetry (DSC), Flow cytometry, Confocal microscopy, Prestoblue and Comet assay. KEY FINDINGS: HR-SF-ICPMS study confirmed >95% complexation of surrogate nuclides of thallium and Iodine applied on excised rat skin mounted over Franz diffusion cell. Temporal analysis of aliquots obtained from Franz diffusion cell using UV-Vis absorption spectroscopy indicated that only 3.37% of formulation permeates through the skin. Skin penetration study of rhodamine 123 nanoemulsion carried out using florescence microscopy confirmed that formulation remains localised in epidermis of rat skin. DSC data confirmed skin compatibility of nanoemulsion, as no lipid extraction was observed from skin. In-vitro cell viability and cellular uptake assays performed on human skin fibroblasts prove no cellular uptake and cytotoxic effects. Comet assay, cell cycle arrest, and apoptosis-inducing mechanistic studies prove that prepared nanoemulsion is safe at cellular level. SIGNIFICANCE: Taken together, data indicate that p-tertbutylcalix[4]arene nanoemulsion is both effective and safe formulation to use on skin for radio-decontamination.


Assuntos
Calixarenos/farmacologia , Calixarenos/farmacocinética , Descontaminação , Absorção Cutânea , Pele/efeitos dos fármacos , Administração Cutânea , Animais , Calixarenos/administração & dosagem , Calixarenos/toxicidade , Linhagem Celular , Descontaminação/métodos , Emulsões/administração & dosagem , Emulsões/farmacocinética , Emulsões/toxicidade , Feminino , Fibroblastos/efeitos dos fármacos , Humanos , Isótopos de Iodo/isolamento & purificação , Isótopos/isolamento & purificação , Masculino , Ratos , Pele/citologia , Pele/metabolismo , Tálio/isolamento & purificação
19.
Microb Pathog ; 101: 76-82, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27836761

RESUMO

Increasing occurrence of gastroenteritis outbreaks caused by food borne opportunistic microorganisms has become a major problem in food industry as well as in immunocompromised host. Antimicrobial agents are losing their efficacy due to increase in the microbial resistance. For such reasons, conventional treatment has become limited to manage the infections state. Need of the hour is to instigate the search for safer holistic alternatives. The present study was hence conducted to assess the antibiofilm effect and mode of action of aquo alcoholic extracts of Holarrhena antidysentrica (Ha) and Andrographis paniculata (Ap) against the Salmonella enterica serovar typhimurium. Both the extracts were screened for the presence of phytocompounds followed by the characterization using Attenuated Total Reflection (ATR) infrared spectroscopy and bioactivity finger print analysis. Anti-biofilm assays were determined to test the potential of both extracts to inhibit the biofilm formation, while Propidium Iodide (PI) uptake analysis revealed that cell membrane was damaged by the exposure of nutraceuticals for 1 h. This study has demonstrated that both nutraceuticals have anti-biofilm and antimicrobial activity perturbing the membrane integrity of food-borne S. typhimurium and could be used as curative remedy to control the food borne microbial infection.


Assuntos
Andrographis/química , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Holarrhena/química , Extratos Vegetais/farmacologia , Salmonella typhimurium/efeitos dos fármacos , Antibacterianos/isolamento & purificação , Biofilmes/crescimento & desenvolvimento , Membrana Celular/fisiologia , Permeabilidade/efeitos dos fármacos , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/isolamento & purificação , Propídio/análise , Salmonella typhimurium/fisiologia , Análise Espectral , Coloração e Rotulagem
20.
J Glob Antimicrob Resist ; 6: 10-16, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27530832

RESUMO

The aim of this study was to analyse the in vitro synergistic antibacterial potential of an aquoethanolic extract of the stem bark of Berberis aristata (PTRC-2111-A) with third-line antibiotics against carbapenem-resistant Escherichia coli. PTRC-2111-A was prepared and was characterised using phytochemical- and bioactivity-based fingerprinting. Fourier transform infrared spectroscopy (FTIR) and liquid chromatography-mass spectrometry (LC-MS) analyses were performed, and superoxide and hydroxyl scavenging activities were assessed in conjunction with in vitro antimicrobial efficacy testing against the test micro-organism. Analysis of drug combinations of PTRC-2111-A and third-line antibiotics was performed using CompuSyn software. PTRC-2111-A from B. aristata was found to have seven common functional groups in comparison with the pre-identified marker compound quercetin, and phytochemical quantitation analysis revealed the presence of 25.44% alkaloids. Moreover, PTRC-2111-A was found to contain isoquinoline alkaloids, namely berbamine, berberine, reticuline, jatrorrhizine, palmatine and piperazine, as elucidated in the LC-MS analysis. Analysis of combinations of PTRC -2111-A and antibiotics revealed synergistic behaviour [fractional inhibitory concentration index (FICI)<1] with colistin, tigecycline and amoxicillin/clavulanate potassium (Augmentin(®)), whereas antagonism (FICI>1) was seen with ertapenem and meropenem.


Assuntos
Antibacterianos/farmacologia , Berberis/química , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Extratos Vegetais/farmacologia , Carbapenêmicos , Sinergismo Farmacológico , Testes de Sensibilidade Microbiana , Casca de Planta/química
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