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1.
Front Pharmacol ; 15: 1428440, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39092235

RESUMO

Background: Boswellin® Super is a standardized extract of Boswellia serrata Roxb gum resin, standardized to contain 30% 3-acetyl-11-keto-ß-boswellic acid along with other ß-boswellic acids (BSE). A randomized, double-blind, placebo-controlled clinical trial was conducted at two doses of BSE to understand its safety and efficacy in supporting joint health and improving mobility and symptoms of osteoarthritis (OA) of the knee. Methods: Based on the inclusion/exclusion criteria, 105 newly diagnosed participants with degenerative hypertrophy OA were recruited and randomized into Placebo, BSE-150 mg or BSE-300 mg (n = 35 in each group) to receive either 150 mg or 300 mg BSE or a placebo tablet twice a day for 90 days. All the participants were evaluated for pain and physical function using the standard tools including the Visual Analog Scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lequesne Functional Index (LFI), EuroQol- 5 Dimension (EQ-5D) quality of life, 6-min walk test at day 0, days 5, 30, 60 and 90 of treatment. Additionally, the circulating levels of inflammatory biomarkers, tumor necrosis factor-α (TNFα), high-sensitive C-reactive protein (hs-CRP), and interleukin-6 (IL-6) were evaluated. Safety was evaluated by blood biochemical, hematological analysis, urinary analyses and by monitoring adverse events throughout the study. Results: Ninety-eight subjects completed the study. Improvements in pain scores were observed as early as 5 days after the start of the supplement in the BSE-150 and BSE-300 groups. By 90 days, the VAS pain score reduced by 45.3% and 61.9%, WOMAC- total score improved by 68.5% and 73.6% in the BSE-150 and BSE-300 groups respectively. WOMAC pain (70.2%, 73.9%, WOMAC stiffness (65.6%,68.9%), WOMAC function (68.8%,74.2%), LFI severity (50%,53.3%), decreased and EQ5D (56.9%, 62.9%) and distance walked in 6 minutes (21.2%, 21.9%) improved in the BSE-150 and BSE-300 groups in 90 days. Further, the levels of TNFα, hs-CRP, and IL-6 were found to decrease in the serum in BSE-supplemented participants. No significant adverse events were recorded during the study. Conclusion: The study confirms that Boswellin® Super can be used as a safe and effective supplement to support joint health and mobility in the management of osteoarthritis. Clinical Trial Registration: https://ctri.nic.in/Clinicaltrials/pmaindet2.php?EncHid=NzU2Nzc=&Enc=&userName=CTRI, identifier CTRI/2022/11/047397.

2.
Am Heart J ; 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39033994

RESUMO

BACKGROUND: Quality of chronic care for cardiovascular disease (CVD) remains suboptimal worldwide. The Collaborative Quality ImProvement (C-QIP) trial aims to develop and test the feasibility and clinical effect of a multicomponent strategy among patients with prevalent CVD in India. METHODS: The C-QIP is a clinic-based, open randomized trial of a multicomponent intervention versus usual care that was locally developed and adapted for use in Indian settings through rigorous formative research guided by Consolidated Framework for Implementation Research (CFIR). The C-QIP intervention consisted of 5 components: 1) electronic health records and decision support system for clinicians, 2) trained non-physician health workers (NPHW), 3) text-message based lifestyle reminders, 4) patient education materials, 5) quarterly audit and feedback reports. Patients with CVD (ischemic heart disease, ischemic stroke, or heart failure) attending outpatient CVD clinics were recruited from September 2022 to September 2023 and were randomized to the intervention or usual care arm for at least 12 months follow-up. The co-primary outcomes are implementation feasibility, fidelity (i.e., dose delivered and dose received), acceptability, adoption and appropriateness, measured at multiple levels: patient, provider and clinic site-level, The secondary outcomes include prescription of guideline directed medical therapy (GDMT) (provider-level), and adherence to prescribed therapy, change in mean blood pressure (BP) and LDL-cholesterol between the intervention and control groups (patient-level). In addition, a trial-based process and economic evaluations will be performed using standard guidelines. RESULTS: We recruited 410 socio-demographically diverse patients with CVD from four hospitals in India. Mean (SD) age was 57.5 (11.7) years, and 73.0% were males. Self-reported history of hypertension (48.5%) and diabetes (41.5%) was common. At baseline, mean (SD) BP was 127.9 (18.2) /76.2 (11.6) mm Hg, mean (SD) LDLc: 80.3 (37.3) mg/dl and mean (SD) HbA1c: 6.8% (1.6%). At baseline, the GDMT varied from 62.4% for patients with ischemic heart disease, 48.6% for ischemic stroke and 36.1% for heart failure. CONCLUSION: This study will establish the feasibility of delivering contextually relevant, and evidence-based C-QIP strategy and assess whether it is acceptable to the target populations. The study results will inform a larger scale confirmatory trial of a comprehensive CVD care model in low-resource settings. TRIAL REGISTRATION: Clinical Trials Registry India: CTRI/2022/04/041847; Clinicaltrials.gov number: NCT05196659.

3.
Sci Rep ; 14(1): 3316, 2024 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-38332177

RESUMO

Effective treatment of breast cancer relies heavily on early detection. Routine annual mammography is a widely accepted screening technique that has resulted in significantly improving the survival rate. However, it suffers from low sensitivity resulting in high false positives from screening. To overcome this problem, adjunctive technologies such as ultrasound are employed on about 10% of women recalled for additional screening following mammography. These adjunctive techniques still result in a significant number of women, about 1.6%, who undergo biopsy while only 0.4% of women screened have cancers. The main reason for missing cancers during mammography screening arises from the masking effect of dense breast tissue. The presence of a tumor results in the alteration of temperature field in the breast, which is not influenced by the tissue density. In the present paper, the IRI-Numerical Engine is presented as an adjunct for detecting cancer from the surface temperature data. It uses a computerized inverse heat transfer approach based on Pennes's bioheat transfer equations. Validation of this enhanced algorithm is conducted on twenty-three biopsy-proven breast cancer patients after obtaining informed consent under IRB protocol. The algorithm correctly predicted the size and location of cancerous tumors in twenty-four breasts, while twenty-two contralateral breasts were also correctly predicted to have no cancer (one woman had bilateral breast cancer). The tumors are seen as highly perfused and metabolically active heat sources that alter the surface temperatures that are used in heat transfer modeling. Furthermore, the results from this study with twenty-four biopsy-proven cancer cases indicate that the detection of breast cancer is not affected by breast density. This study indicates the potential of the IRI-Numerical Engine as an effective adjunct to mammography. A large scale clinical study in a statistically significant sample size is needed before integrating this approach in the current protocol.


Assuntos
Neoplasias da Mama , Feminino , Humanos , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Mamografia/métodos , Densidade da Mama , Temperatura Alta , Mama/diagnóstico por imagem , Mama/patologia , Detecção Precoce de Câncer/métodos
4.
J Integr Complement Med ; 30(3): 233-249, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37878297

RESUMO

Introduction: Endothelial dysfunction is the initial step in the pathogenesis of atherosclerosis; and it plays a central role in the development of cardiovascular diseases and many types of human diseases (diabetes, kidney failure, cancer, and viral infections). Strategies that are effective in protecting vascular endothelial function and retard or reversing endothelial dysfunction in the early stage appear to be potential in the prevention of vascular, cardiac, and many human diseases. Several studies have been carried out on the effects of yoga on endothelial function, but the results of these studies have not been synthesized. This study aimed at conducting a systematic review and meta-analysis to determine the effectiveness of yoga on endothelial function. Methods: A systematic review and meta-analysis of studies that assessed the effect of yoga practice on vascular endothelial function was done as per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, Scopus, Google Scholar, and Cochrane controlled register of trials (CENTRAL) were searched from inception to August 2022. The search strategy was constructed around yoga-based techniques and endothelial function. All the yoga-based interventional studies on endothelial function or dysfunction were included in this review. A narrative synthesis and descriptive analysis were done due to the diverse methodology of selected studies. We carried out a formal meta-analysis of controlled trials that assessed the effect of yoga on flow-mediated dilatation (FMD), a measure of endothelial function. Results: A total of 18 studies were included for review involving 1043 participants. Yoga training showed improved endothelial function in 12 studies, whereas 6 studies did not find any statistically robust effect. Meta-analysis (n = 395 participants, 6-studies, 7 comparisons) showed an increase in brachial FMD by yoga practice (mean difference = -1.23%; 95% confidence interval -2.23 to -0.23; p = 0.02). The heterogeneity between the studies was 43% (Tau2 = 0.70, χ2 = 10.49). The risk of bias was low to moderate in these studies. No adverse effects were reported. Conclusions: Yoga practice improved endothelial function. Yoga could be a safe and potential integrative medicine to improve endothelial function. However, as the statistical heterogeneity, that is, variation in the FMD among the studies was moderate, large clinical trials are necessary for its clinical recommendations.


Assuntos
Aterosclerose , Doenças Cardiovasculares , Yoga , Humanos , Doenças Cardiovasculares/prevenção & controle
5.
AAPS J ; 26(1): 10, 2023 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-38133698

RESUMO

RNA therapeutics, including siRNAs, ASOs, and PMOs, have great potential to treat human disease. However, RNA therapeutics are too large, too charged, and/or too hydrophilic to cross the cellular membrane and are instead taken up into cells by endocytosis. Unfortunately, the vast majority of RNA therapeutics remain trapped inside endosomes (≥ 99%), which is the sole reason preventing their use to treat cancer, COVID, and other diseases. In contrast, enveloped viruses, such as influenza, also have an endosomal escape problem, but have evolved a highly efficient endosomal escape mechanism using trimeric hemagglutinin (HA) fusogenic protein. HA contains an outer hydrophilic domain (HA1) that masks an inner hydrophobic fusogenic/endosomal escape domain (HA2). Once inside endosomes, HA1 is shed to expose HA2 that, due to hydrophobicity, buries itself into the endosomal lipid bilayer, driving escape into the cytoplasm in a non-toxic fashion. To begin to address the RNA therapeutics rate-limiting endosomal escape problem, we report here a first step in the design and synthesis of a universal endosomal escape domain (uEED) that biomimics the enveloped virus escape mechanism. uEED contains an outer hydrophilic mask covalently attached to an inner hydrophobic escape domain. In plasma, uEED is inert and highly metabolically stable; however, when placed in endo/lysosomal conditions, uEED is activated by enzymatic removal of the hydrophilic mask, followed by self-immolation of the linker resulting in exposure of the hydrophobic indole ring domain in the absence of any hydrophilic tags. Thus, uEED is a synthetic biomimetic of the highly efficient viral endosomal escape mechanism.


Assuntos
Endocitose , Endossomos , Humanos , Endossomos/metabolismo , Proteínas/metabolismo , RNA Interferente Pequeno/metabolismo , Membrana Celular
6.
Nucleic Acid Ther ; 32(5): 361-368, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35612432

RESUMO

RNA therapeutics, including siRNAs, antisense oligonucleotides, and other oligonucleotides, have great potential to selectively treat a multitude of human diseases, from cancer to COVID to Parkinson's disease. RNA therapeutic activity is mechanistically driven by Watson-Crick base pairing to the target gene RNA without the requirement of prior knowledge of the protein structure, function, or cellular location. However, before widespread use of RNA therapeutics becomes a reality, we must overcome a billion years of evolutionary defenses designed to keep invading RNAs from entering cells. Unlike small-molecule therapeutics that are designed to passively diffuse across the cell membrane, macromolecular RNA therapeutics are too large, too charged, and/or too hydrophilic to passively diffuse across the cellular membrane and are instead taken up into cells by endocytosis. However, similar to the cell membrane, endosomes comprise a lipid bilayer that entraps 99% or more of RNA therapeutics, even in semipermissive tissues such as the liver, central nervous system, and muscle. Consequently, before RNA therapeutics can achieve their ultimate clinical potential to treat widespread human disease, the rate-limiting delivery problem of endosomal escape must be solved in a clinically acceptable manner.


Assuntos
COVID-19 , Bicamadas Lipídicas , Humanos , Bicamadas Lipídicas/metabolismo , COVID-19/genética , COVID-19/terapia , Endossomos/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/uso terapêutico , RNA Interferente Pequeno/química , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/uso terapêutico , Oligonucleotídeos Antissenso/metabolismo , Oligonucleotídeos/metabolismo
7.
Org Biomol Chem ; 20(12): 2518-2529, 2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35266938

RESUMO

Scandium triflate (Sc(OTf)3) catalyzed, mild, and regioselective ring-opening reaction of donor-acceptor (D-A) cyclopropanes has been developed using sulfoximines for the synthesis of γ-sulfoximino malonic diesters. This protocol allows the synthesis of different N-alkyl sulfoximines in good to excellent yields (up to 94%) with broad functional group tolerance. In this process, N-H and C-C bonds are cleaved to form new C-N and C-H bonds. The feasibility of this method is supported by a gram-scale reaction and synthetic elaboration of the obtained product.

8.
J Org Chem ; 86(15): 10129-10139, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34264087

RESUMO

We have reported an efficient and metal-free method for the construction of α-diarylmethine imino sulfanone using acid-catalyzed 1,6-conjugate addition of sulfoximines on para-quinine methides (p-QMs). This method showed broad functional group tolerance and a wide range of substrate scope with good to excellent yield. The excellent protocol exhibits mild reaction conditions with high atom economy. The practicability of the present method was supported by a Gram-scale reaction.


Assuntos
Indolquinonas , Metais , Catálise , Quinina
9.
Nat Mater ; 20(5): 575-577, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33911220
10.
J Org Chem ; 86(3): 2107-2116, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33492145

RESUMO

The highly regioselective synthesis of substituted hemiaminal via addition of ethers to quinone imine ketals (QIKs) has been developed under metal-free conditions. In the presence of tetrabutylammonium chloride and potassium persulfate (K2S2O8), QIKs couple efficiently with cyclic and acyclic ethers to give hemiaminals. This strategy offers an easy access to substituted hemiaminal ethers with high functional group tolerance in good to excellent yields.

11.
Curr Hypertens Rev ; 17(3): 245-249, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33475075

RESUMO

BACKGROUND: Increased arterial stiffness is an independent predictor of cardiovascular morbidity and mortality. It is unknown whether low BMI has any detrimental effect on the arterial wall during young age. OBJECTIVES: The present study was aimed to determine if low BMI can increase arterial stiffness in young, healthy individuals. METHODS: A cross-sectional study was conducted on young, healthy subjects (n=100) with low BMI <18.5 (n=50) and normal BMI: 18.5-24.9 (n=50) with ages ranging between 15-23 years. BMI, heart rate, blood pressure, and arterial stiffness indices such as regional pulse wave velocity (PWV) between brachial-ankle (baPWV), carotid-femoral (cfPWV), heart-ankle (haPWV), heartbrachial (hbPWV) were measured. RESULTS: A significantly increased pulse pressure (p=0.014), baPWV (1059.2 ± 140.26 cm/s vs 994.66 ± 129.23 cm/s; p=0.019) and cfPWV (641.03 ± 113.83 cm/s vs 583.96 ± 120.48 cm/s; p=0.017) was found in individuals with low BMI than normal BMI group. There was a significant negative correlation between BMI and central arterial PWV. Further multiple regression analysis showed that BMI was robustly associated with cf-PWV (p=0.004) and baPWV (p=0.016) even after multiple adjustments with potential confounders using several models. CONCLUSION: These findings show a significant increased aortic stiffness and pulse pressure in low BMI subjects compared to those with normal BMI. Low BMI was inversely and independently associated with central arterial or aortic stiffness. These findings suggest that low BMI may be a risk factor for aortic stiffness in young, healthy individuals.


Assuntos
Rigidez Vascular , Adolescente , Adulto , Índice Tornozelo-Braço , Pressão Sanguínea , Índice de Massa Corporal , Artéria Braquial , Estudos Transversais , Humanos , Análise de Onda de Pulso , Adulto Jovem
12.
Rev Sci Instrum ; 91(10): 104702, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33138573

RESUMO

There is an increasing interest in synchronization of multiple spark gap switches while maintaining compact geometry, less-complex circuit, and low jitter switching performances. A study of the effect of electrical parameters on switching performances is necessary for the operation of a large number of simultaneous switches. A miniaturized trigatron switch assembly (Outer diameter: 35 mm and thickness: 5 mm) is developed and experimentally investigated for switching performance. A polyether ether ketone insulator and brass conductor electrodes are utilized due to their high insulation and solderable properties, respectively. Important switching parameters, delay time, switch time delay, jitter in delay time, discharging peak current, trigger break down time, and trigger break down voltage, are studied under four typical conditions. These four conditions are: (a) a fast trigger (FT) with normal circuit inductance (10 ns, 20 nH); (b) a fast trigger with higher circuit inductance (10 ns and 500 nH); (c) a slow trigger (ST) with normal circuit inductance (250 ns and 20 nH) and (d) a slow trigger with higher circuit inductance (250 ns and 500 nH). Subsequently, three trigatron spark gaps (4 kV, 5 kA, >100 shots, 4 nH, and 20 mΩ) are simultaneously switched within 5 ns time. Many experimental results are the first of their kind in terms of compact switch development, switching performance, and single electrical trigger based synchronization. This paper will also add a good value to presently available knowledge through systematically implementing the simultaneous switching condition for the generation of 5 kA, 50 ns current pulses. These low cost (US$40) trigatron switches can be utilized in low energy, compact pulsed power applications.

13.
Complement Ther Med ; 52: 102484, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32951734

RESUMO

OBJECTIVES: Arterial stiffness is a major cardiovascular (CV) risk and an independent strong predictor of CV morbidity and mortality. The aim of this systematic review is to evaluate the clinical or interventional studies that assessed the effectiveness of yoga on arterial stiffness in participants of any age or sex, healthy or with any conditions. DESIGN: Systematic review of clinical trials or interventional studies. DATA SOURCES: Cochrane Library, Medline/PubMed, Scopus, and Google Scholar databases. REVIEW METHODS: Databases were searched till July 2019 for clinical trials or interventional studies whether controlled or uncontrolled, randomized or non-randomized studies assessing the effects of yoga on arterial stiffness. Quality of the studies was assessed by using Physiotherapy Evidence Database (PEDro) Scale. RESULTS: Seven full-text articles (total number of participants = 362) that evaluated the effect of yoga on arterial stiffness were included in this review. There were three randomized controlled studies and four were non-controlled studies (single group studies). Four studies have shown significant reduction in arterial stiffness, while three studies did not find any significant change in arterial stiffness. The beneficial effects of yoga intervention on arterial stiffness in young adults and elderly hypertensive patients are encouraging. Methodological quality was good for one study, moderate for two studies and poor for four studies. CONCLUSIONS: This review shows that yoga practice is effective in preventing or reducing the arterial stiffness in young healthy and obese, and elderly hypertensive patients. As the methodology of many studies is of low quality and safety measures were not reported, there is a need of quality randomized controlled trials of yoga effects on arterial stiffness among high risk individuals.


Assuntos
Meditação/métodos , Rigidez Vascular/fisiologia , Yoga , Humanos , Hipertensão/prevenção & controle
14.
Exp Eye Res ; 200: 108230, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32931824

RESUMO

One of the major public health issues is the rising prevalence of cataracts, a primary reason for preventable blindness. The causes for the development of age-related cataracts and accelerated cataractogenesis in diabetes are multifactorial. Hence, this study was designed to examine the status and relationship between the three majorly associated molecular events, namely, oxidative stress, non-enzymatic glycation, and polyol pathway in age-related cataracts with and without diabetes. A total of 472 subjects were distributed into four groups: non-diabetic subjects with clear lens (135), diabetic subjects with clear lens (40), non-diabetic subjects with cataract (174), and diabetic subjects with cataract (123). Cataracts were graded by slit-lamp examination according to the Lens Opacities Classification System III. Age at onset of cataract, type of opacity, anthropometric measurements, and sociodemographic characteristics were recorded, and clinical profile was examined. Plasma oxidative stress markers were assessed by estimating the lipid peroxidation end product malondialdehyde, protein oxidation products protein carbonyls, and DNA oxidative damage marker 8-hydroxy-2-deoxyguanosine. Plasma advanced glycation end products index, erythrocyte aldose reductase activity, and sorbitol levels were evaluated. After adjusting for age, plasma malondialdehyde levels were significantly higher in diabetic cataracts (P < 0.001) and non-diabetic cataract subjects (P < 0.05), compared to non-diabetic subjects with clear lens. Plasma advanced glycation end products index was significantly higher (P < 0.05) only in diabetic cataracts, but not in non-diabetic subjects with cataracts. Aldose reductase activity and sorbitol levels were significantly higher (P < 0.001) in both diabetic and non-diabetic subjects with cataract compared to non-diabetic subjects with clear lens. The data indicated that plasma lipid peroxidation in age-related cataracts was independent of diabetes. An association of pronounced glycation was observed only in diabetic cataracts but not in non-diabetic cataracts and polyol flux between diabetic cataracts and non-diabetic cataracts was comparable.


Assuntos
Catarata/metabolismo , Diabetes Mellitus/metabolismo , Produtos Finais de Glicação Avançada/metabolismo , Cristalino/metabolismo , Estresse Oxidativo , Polímeros/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/metabolismo , Catarata/complicações , Feminino , Seguimentos , Glicosilação , Humanos , Peroxidação de Lipídeos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
15.
J Family Med Prim Care ; 9(4): 2045-2051, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32670963

RESUMO

BACKGROUND: Oral health is integral part of general health. In certain conditions especially among mentally disabled, oral health is neglected. Studies have shown that mentally disabled population has the risk of poor oral health. People with disabilities deserve the same opportunities for oral health and hygiene as those who are healthy, but sadly dental care is the most common unmet health care need of the disabled people. METHODOLOGY: This comparative, descriptive cross-sectional study was conducted among institutionalized mentally disabled and normal children of age group 6-13 years in Mysore city. RESULTS: Majority of mentally disabled children, that is, 36.73% (n = 180), had poor oral hygiene when compared with normal children, that is, 9.18% (n = 45). This difference was statistically highly significant (P < 0.000). The significant differences in the gingival status and severity of mental disability were seen (P < 0.001). The result showed that the gingival health worsens with increase in the severity of mental disability. CONCLUSION: The present study showed the dental negligence among mentally disabled children where the parents, caretakers, and dentists are responsible. Oral health promotion programs should be conducted for special group children, their parents, as well as caretakers.

16.
Sci Rep ; 10(1): 11941, 2020 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-32686716

RESUMO

We demonstrate a novel technique to achieve highly surface active, functional, and tunable hierarchical porous coated surfaces with high wickability using a combination of ball milling, salt-templating, and sintering techniques. Specifically, using ball-milling to obtain graphene nanoplatelets (GNP) draped copper particles followed by salt templated sintering to induce the strength and cohesiveness to the particles. The salt-templating method was specifically used to promote porosity on the coatings. A systematic study was conducted by varying size of the copper particles, ratio of GNP to copper particles, and process parameters to generate a variety of microporous coatings possessing interconnected pores and tunnels that were observed using electron microscopy. Pool boiling tests exhibited a very high critical heat flux of 289 W/cm2 at a wall superheat of just 2.2 °C for the salt templated 3 wt% GNP draped 20 µm diameter copper particles with exceedingly high wicking rates compared to non-salt-templated sintered coatings. The dramatic improvement in the pool boiling performance occurring at a very low surface temperature due to tunable surface properties is highly desirable in heat transfer and many other engineering applications.

17.
Iran J Microbiol ; 12(2): 138-147, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32494348

RESUMO

BACKGROUND AND OBJECTIVES: Excess use of pesticides in agricultural field not only compromised soil fertility but also posed serious threat to water bodies and life in the surrounding environment. The leftover pesticide residue needs to be remediated effectively. Compared to physical, chemical and enzymatic remediation options the microbial remediation is more practical and sustainable. MATERIALS AND METHODS: The Pseudomonas stutzeri smk strain was found to use dichlorvos as the solitary carbon source. Minimal medium supplemented with dichlorvos was used to test ability of bacterium to degrade pesticide aerobically. The metabolites produced by the bacterium were studied with UV-Vis spectrophotometry, HPLC, FTIR and GC-MS techniques. The toxicity studies of neat dichlorvos and P. stutzeri smk degraded metabolites were studied by subcutaneous injection in Mus musculus. RESULTS: The P. stutzeri smk strain was found to degrade as high as 80% of dichlorvos on 7th day of incubation, at 30 °C temperature and at pH 7. In five steps complete aerobic degradation of 2,2dicholorvinyl dimethyl phosphate (dichlorvos) resulted in production of free methyl and phosphate. The degradation intermediates produced are 2-Chlorovinyl dimethyl phosphate, vinyl dimethyl phosphate, dimethyl phosphate, methylphosphate and finally free phosphate. The histopathological analysis of liver, spleen and thymus of M. musculus were performed to study toxicity of dichlorvos and degraded metabolites. CONCLUSION: P. stutzeri smk could result highest aerobic degradation of dichlorvos to produce free methyl and phosphate. Degradation metabolites could reverse largely toxic effects of dichlorvos when studied in M. musculus.

18.
Eur Phys J E Soft Matter ; 42(12): 159, 2019 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-31863297

RESUMO

Compared to nanofluids with spherical particles, nanofluids with anisotropic particles possess higher thermal conductivity and present a better enhancement option in heat transfer applications. The viscosity variation of such nanofluids becomes of great importance in evaluating their pumping power in thermal systems. This paper presents a comprehensive review of the experimental and theoretical studies on the viscosity of nanofluids with anisotropic particles. The internal mechanisms of viscosity evolution are investigated considering three aspects: particle clustering, particle interactions, and Brownian motion. In experimental studies, important factors including classification and synthetic methods for particle preparation, base fluid, particle loading, particle shape and size, temperature, p H, shear stress and electric field are investigated in detail. Classical theoretical models and empirical relations of the effective viscosity of suspensions are discussed. Some crucial factors such as maximum particle packing fraction, fractal index and intrinsic viscosity models, are examined. A comparison of predictions and experimental results shows that the classical models underestimate suspension viscosity. A comprehensive combination of the modified Krieger-Dougherty (K-D) model with intrinsic viscosity relations for different aspect ratios is suggested for low particle loadings, and the modified Maron-Pierce model (M-D) is recommended for high particle loadings. Possible directions for future works are discussed.

19.
Langmuir ; 35(25): 8294-8307, 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31141373

RESUMO

The collision of a bubble at liquid?liquid, solid?liquid?liquid, and gas?liquid?liquid interfaces, the latter two of which are referred to as compound interfaces, is modeled to predict the bubble?s velocity profile and the pressure buildup and drainage rate of the film(s) formed at impact. A force balance approach, previously outlined for bubble collisions at solid and free surfaces, is employed, which takes into account four forces acting on the bubble: buoyancy, drag, inertia of the surrounding liquid through an added mass force, and a film force resulting from the pressure buildup in the liquid film formed between the bubble and the interface upon impact. The augmented Young?Laplace equation is applied to define the pressure buildup in the film(s), while lubrication theory is employed to define the film drainage rate(s) through the use of the Stokes?Reynolds equation. This is the first time this modeling technique has been implemented for bubble collisions with these interface types as all previous models have relied only on grid-based simulations. The models were validated through experiments conducted here with water and silicone oils of various viscosities and from data found in literature. A reasonable agreement is observed between the theoretical and experimental velocity profiles found for these liquid combinations under varying conditions of impact velocity and top film thickness. The spatiotemporal film thickness and pressure profile evolution, features not yet able to be captured through experiment, are also presented and discussed.

20.
J Environ Public Health ; 2019: 4807913, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30944570

RESUMO

Overuse of pesticides in agriculture may harm environmental and agricultural yields. Sustainable maintenance of soil fertility and management of the environment have become a concern due to the persistence of pesticides in the soil. Microbes have various mechanisms for the bioremediation of persistent organic pollutants from the environment. A bacterium that degrades clothianidin was isolated from the pesticide and applied to agricultural soil by the enrichment technique. The identity of the bacterium was determined by studying morphological, cultural, and biochemical characteristics and 16S rRNA gene sequences. The ability to metabolize clothianidin was confirmed using UV-visible spectrophotometric, chromatographic, and spectroscopic analyses. A Gram-negative bacterium, designated smk, isolated from clothianidin-contaminated soil was confirmed to be a member of Pseudomonas stutzeri. The biodegradation of clothianidin was studied using P. stutzeri smk. Approximately 62% degradation of clothianidin was achieved within two weeks when grown at 30°C and pH 7. The effects of various physicochemical parameters, including pH, temperature, and clothianidin concentrations, on catabolic rates were studied. The biodegradation studies using UV-Vis spectrophotometry, HPLC, FTIR, and LC-MS indicated the production of the following metabolites: 2-chloro-5-methyl thiazole (CMT), methyl nitroguanidine (MNG), methyl 3-[thiazole-yl], and methyl guanidine (TMG). Identification of specific degradation metabolites indicates that bioremediation of toxic neonicotinoid insecticides may be achieved by application of P. stutzeri smk.


Assuntos
Guanidinas/metabolismo , Inseticidas/metabolismo , Neonicotinoides/metabolismo , Pseudomonas stutzeri/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Tiazóis/metabolismo , Agricultura , Biodegradação Ambiental , Pseudomonas stutzeri/classificação , Pseudomonas stutzeri/genética , RNA Ribossômico 16S/genética
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