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1.
Heliyon ; 10(2): e24149, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-38293457

RESUMEN

This study introduces a numerical model to assess the thermal and frictional properties of LBE crossflow over tube bundles on the shell side of a Helical-coiled Once-Through Steam Generator (H-OTSG) considering different arrangements, including inline, obliquely staggered, triangular, and rotated square configurations. The k-ω SST turbulence model combined with Kays turbulent Prandtl number model is utilized to develop the numerical model. The simulation results have been validated against experimental data and empirical correlations. The layouts of the tube bundles significantly influence the generation of transverse flow, vortical structures and rate of heat transfer in the flow domain. The maximum Nusselt number of 8.2 is observed for the triangular layout as significant crossflow is induced, which is a 10% increase compared to the inline arrangement where the Nusselt number is 7.45. Triangle layouts also exhibit a higher friction factor of 0.45, marking a 20% increase compared to the 0.45 friction factor observed in the inline arrangement. Increasing the oblique angle usually reduces the heat transfer rate and friction factor. Yet, at a 45-degree layout, higher turbulence intensity results in a Nu of 7.05, surpassing 6.93 observed at 30° but falling short of 7.15 at 15°. Nu decreases for rotated square arrangements, but a friction factor greater than the inline arrangement is observed at higher diagonal pitches. The Thermal Enhancement Factor (THEF) is employed to assess the thermal effectiveness of the different tube bundle layouts, and the maximum THEF of 1.1 is observed for the layout with an oblique angle of 45°. Favorable THEF values of 1.06 and 1.05 are recorded for the triangular layout and 30-degree oblique angle, respectively. This numerical study will assist the design and development of LBE H-OTSG.

2.
Sci Rep ; 13(1): 18452, 2023 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-37891218

RESUMEN

This research paper investigates the optimization of radiation performance of a plasma-based bioconvective nanofluid integrated Magneto-hydrodynamic (MHD) micropump for radiative oncology. It addresses a literature gap by analysing the radiative impact of blood-based hybrid nanofluids in MHD micropumps. Three blood-based bio-convective radiating hybrid nanofluids-blood-Pt, blood-Au and blood-MWCNT are studied to understand their radiation behaviour in MHD pump while being employed as transportation medium. The investigation employs two non-dimensional parameters, namely Rd (Radiation number) and Ha (Hartmann number), to examine the fluid dynamics, magnetic characteristics, and electrical properties of the MHD micropump. The temperature gradient, velocity distribution, and pressure drop along the flow channel are examined within the specified range of Rd and Ha. Magnetic flux density (MFD) and electric flux intensity (EFI) are evaluated to understand nanoparticle behaviour during drug delivery and blood transportation. Findings highlight that MWCNT and Pt are the most efficient bioconvective nanoparticles for plasma transportation under high radiative conditions. MWCNT-based blood flow exhibits desirable characteristics, including sufficient intake pressure of 4.5 kPa and minimal relative pressure drop of 34%. Coherence between radiation flux and electromagnetic flux reduces pumping power and ensures uniform heat dissipation for improved drug delivery. Au nanoparticles provide moderate magnetic flux density with least fluctuation within the range of Ha and Rd number (2.57 T to 4.39 T), even in highly radiative environments (such as-Rd = 4, Rd = 5), making them suitable for applications like embedded chemotherapy or cell treatment. Au nanoparticles maintain moderate electrical flux intensity with a minimal drop of 16nA, particularly at higher radiative environments influenced by the Radiation number (Rd = 4 to Rd = 5) while Ha values from Ha = 2 to Ha = 4. Conclusively, it has been identified that MWCNT and Au are superior nanofluids for advanced radiative oncological treatments. These nanofluids have the potential to enhance plasma transportation, thermal regulation, and aetilogical disease management. The present study provides significant findings on enhancing the radiation performance in MHD micropumps through utilization of blood-based hybrid nanofluids, thereby offering potential advantages to the domain of biomedical engineering.

3.
MethodsX ; 11: 102401, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37817981

RESUMEN

This paper presents the design and construction of a hydroponics monitoring system that can collect parameters of hydroponic systems, such as temperature, water limit, pH level, and nutrient levels. The monitoring system was developed using an ESP32 microcontroller and several sensors, including total dissolved solids (TDS), pH, water level, and temperature sensors. The ESP32 microcontroller gathers and processes data from the sensors to automatically activate the water or salt pump and drain the necessary materials into the hydroponic system's plant basin. The user can then view the hydroponic parameters through the Blynk application on a smartphone. The user can also activate the pumps for water, nutrients, or salt using the application's interface on a smartphone, or the ESP32 microcontroller can activate them automatically if the parameter values deviate from the required values. The monitoring hydroponics system and IoT interface were successfully built and implemented. The experiments were compiled, and the data gathered and discussed.•An ESP32 microcontroller with TDS, pH, water level, and temperature sensors was used to build the hydroponic monitoring system.•The ESP32 automatically collects and evaluates sensor data in order to drain water nutrients, or salt into the plant basin of the hydroponic system as necessary.•The user can also check the parameters of the hydroponic system and, if necessary, run the pumps for water, fertilizers, or salt using his smartphone through the Blynk IoT app.

4.
ACS Omega ; 8(24): 21830-21841, 2023 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-37360433

RESUMEN

Drilling fluids, commonly referred to as drilling mud, are pumped into the wellbore to expedite the drilling process by moving drilling cuttings to the surface, suspending cuttings, controlling pressure, stabilizing exposed rock, and providing buoyancy, cooling, and lubrication. Understanding the settling of drilling cuttings in base fluids is crucial for successfully mixing drilling fluid additives. In this study, the response surface method Box-Benhken design (BBD) is used to analyze the terminal velocity of the drilling cuttings in a polymeric base fluid of carboxymethyl cellulose (CMC). The impact of polymer concentration, fiber concentration, and cutting size on the terminal velocity of the cuttings is investigated. The BBD of the three factors (low, medium, and high) is used for two fiber aspect ratios (3 and 12 mm length). The size of the cuttings varied between 1 and 6 mm, while the concentration of CMC was between 0.49 and 1 wt %. The concentration of the fiber was in the range of 0.02-0.1 wt %. Minitab was utilized to determine the optimum conditions for reducing the terminal velocity of the suspended cuttings and then evaluate the effects and interactions of the components. The results show good agreement between model predictions and the experimental results (R2 = 0.97). According to the sensitivity analysis, cutting size and polymer concentration are the most crucial factors affecting the terminal cutting velocity. Large cutting sizes have the most significant impact on polymer and fiber concentrations. The optimization results revealed that a CMC fluid with a viscosity of 630.4 cP is sufficient to maintain a minimum cutting terminal velocity of 0.234 cm/s with a cutting size of 1 mm and a 0.02 wt % of the 3 mm length fiber.

5.
Artículo en Inglés | MEDLINE | ID: mdl-36817293

RESUMEN

Clonorchis Sinensis, a common liver fluke, is known to cause biliary disease and can present with a wide array of symptoms. It's mostly found in Asian countries due to consumption of undercooked or raw fish. Although Cholangiocarcinoma is a known serious complication of this disease, Pancreatic neoplasms are rare and have seldom been reported. Here, we report a case of an 80-year-old man who presents with pancreatic adenocarcinoma associated with Clonorchis Sinensis infection.

6.
Artículo en Inglés | MEDLINE | ID: mdl-36817304

RESUMEN

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive genetic disorder which commonly affects males. It is due to a defect in the red blood cell enzyme, G6PD. Lack of G6PD makes the RBCs vulnerable to oxidant stress resulting in hemolysis. The severity of hemolytic anemia varies among individuals with G6PD deficiency. Here we present a case of an 80-year-old man admitted with syncope and jaundice. He was treated with phenazopyridine for a UTI 2 weeks ago. Subsequent investigation revealed G6PD deficiency as well as methemoglobinemia. Historically, phenazopyridine has been associated with causing methemoglobinemia and triggering hemolysis in G6PD deficient individuals. However, only a few cases have been reported in the last 60 years, making it a very rare occurrence.

7.
Cureus ; 14(6): e26014, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35720779

RESUMEN

Cardiac tumors are an uncommon phenomenon. Although they can be cardiac in origin, most represent a distant neoplastic growth metastasizing to the heart. Cardiac tumors can be benign or malignant. They may be symptomatic or, more commonly, found incidentally. Clinical presentation is typically related to that of dispersed neoplasm. We report a case of a 36-year-old young man with an unusually large and smooth-surfaced right ventricular mass. The patient presented to the emergency department with exertional dyspnea for two weeks. Past medical history was significant for deep venous thrombosis with non-adherence to anti-coagulation. Computerized tomographic (CT) angiography showed bilateral pulmonary emboli and a hypodense opacity in the right ventricle. A transthoracic echocardiogram showed a right ventricular non-mobile mass. The patient underwent surgical removal of the mass, which pathology demonstrated to be a thrombus. Cardiac masses can be difficult to differentiate based on imaging alone. Physicians should maintain a high index of suspicion for intracardiac thrombi as early identification and prompt treatment are imperative in improving patient outcomes.

8.
Cult Med Psychiatry ; 46(2): 531-563, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34328610

RESUMEN

In low- and middle-income countries (LMIC) it is vital to understand acceptable, comprehensive, and culturally appropriate ways of communicating about mental distress. Diagnostic terminology is rarely used, may be stigmatizing, and is subject to misinterpretation. Local terms, such as idioms of distress, can improve mental health literacy and service delivery. Our objective was to examine lived experience and coping connected to distress and depression in an under-researched population: young men from LMIC urban slums. We conducted 60 qualitative interviews with men (ages 18-29) in Bhashantek slum, Bangladesh. Themes were generated using thematic analysis and grounded theory techniques. The heart-mind (mon), mentality (manoshikota), mood (mejaj), head (matha or "brain"), and body (shorir) comprised the self-concept, and were related to sadness, hopelessness, anger, worry, and mental illness. The English word "tension" was the central idiom of distress. "Tension" existed on a continuum, from mild distress or motivational anxiety, to moderate distress including rumination and somatic complaints, to severe psychopathology including anhedonia and suicidality. Respondents connected "tension" to burnout experiences and mental illness which was summarized in an ethnopsychological model. These findings can inform culturally sensitive measurement tools and interventions that are acceptable to the community, potentially increasing engagement and enhancing therapeutic outcomes.


Asunto(s)
Depresión , Áreas de Pobreza , Adolescente , Adulto , Ansiedad , Bangladesh , Etnopsicología , Humanos , Masculino , Adulto Joven
9.
Anim Biotechnol ; 33(6): 1134-1141, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33509025

RESUMEN

The current study was conducted to investigate effects of copper (sulfate, acetate and nano) in ovo injection at 10 days of the embryogenesis period on body weight (BW), immunity, biochemical parameters and carcass traits of broiler chicks at 35 days of age. A total number of 462 fertile eggs were used in seven groups, each group containing 66 eggs in three replicates. The experimental design was as follows: the group 1 as a control, while groups 2, 3 and 4 injected with 8 µg/egg of Cu sulfate, Cu acetate and nano Cu, respectively, and groups 5, 6 and 7 injected with 16 µg/egg of Cu sulfate, Cu acetate and nano Cu, respectively. Results stated that BW was increased in Cu-injected groups, except groups of Cu acetate, but plasma constituents, carcass and relative weight of organs did not affect. Cu level (8 µg/egg) had better results than Cu level (16 µg/egg). No differences between among groups in relative weights of spleen and bursa and immune response. In conclusion, it is recommended that in ovo injection of different sources of Cu can augment the BW and did not harmfully affect immunity, carcass traits and biochemical parameters of broiler chicks.


Asunto(s)
Pollos , Cobre , Animales , Pollos/fisiología , Cobre/farmacología , Peso Corporal , Sulfatos , Inmunidad
10.
Cureus ; 13(8): e17136, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34532174

RESUMEN

We report a case of non-bacterial thrombotic endocarditis in a 52-year-old woman due to ovarian cancer that was complicated by acute ischemic stroke through pulmonary arteriovenous malformation. Echocardiography showed tricuspid valve vegetation and a positive bubble study that revealed pulmonary arteriovenous malformation in the absence of patent foramen ovale. The patient opted for palliative management and was discharged home with comfort care.

11.
BMC Psychiatry ; 21(1): 291, 2021 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-34088289

RESUMEN

BACKGROUND: Binary categorical approaches to diagnosing depression have been widely criticized due to clinical limitations and potential negative consequences. In place of such categorical models of depression, a 'staged model' has recently been proposed to classify populations into four tiers according to severity of symptoms: 'Wellness;' 'Distress;' 'Disorder;' and 'Refractory.' However, empirical approaches to deriving this model are limited, especially with populations in low- and middle-income countries. METHODS: A mixed-methods study using latent class analysis (LCA) was conducted to empirically test non-binary models to determine the application of LCA to derive the 'staged model' of depression. The study population was 18 to 29-year-old men (n = 824) from an urban slum of Bangladesh, a low resource country in South Asia. Subsequently, qualitative interviews (n = 60) were conducted with members of each latent class to understand experiential differences among class members. RESULTS: The LCA derived 3 latent classes: (1) Severely distressed (n = 211), (2) Distressed (n = 329), and (3) Wellness (n = 284). Across the classes, some symptoms followed a continuum of severity: 'levels of strain', 'difficulty making decisions', and 'inability to overcome difficulties.' However, more severe symptoms such as 'anhedonia', 'concentration issues', and 'inability to face problems' only emerged in the severely distressed class. Qualitatively, groups were distinguished by severity of tension, a local idiom of distress. CONCLUSIONS: The results indicate that LCA can be a useful empirical tool to inform the 'staged model' of depression. In the findings, a subset of distress symptoms was continuously distributed, but other acute symptoms were only present in the class with the highest distress severity. This suggests a distress-continuum, disorder-threshold model of depression, wherein a constellation of impairing symptoms emerge together after exceeding a high level of distress, i.e., a tipping point of tension heralds a host of depression symptoms.


Asunto(s)
Depresión , Áreas de Pobreza , Adolescente , Adulto , Asia , Bangladesh , Depresión/diagnóstico , Humanos , Análisis de Clases Latentes , Masculino , Adulto Joven
12.
J Hosp Med ; 16(5): 282-289, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33929948

RESUMEN

OBJECTIVE: To describe the seroprevalence and risk for SARS-CoV-2 among healthcare workers (HCWs) by job function and work location following the pandemic's first wave in New York City (NYC). METHODS: A cross-sectional study conducted between May 18 and June 26, 2020, during which HCWs at a large inner-city teaching hospital in NYC received voluntary antibody testing. The main outcome was presence of SARS-CoV-2 antibodies indicating previous infection. Seroprevalence and adjusted odds ratios (aORs) for seropositivity by type and location of work were calculated using logistic regression analyses. RESULTS: Of 2,749 HCWs tested, 831 tested positive, yielding a crude seroprevalence of 30.2% (95% CI, 29%-32%). Seroprevalence ranged from 11.1% for pharmacy staff to 44.0% for nonclinical HCWs comprised of patient transporters and housekeeping and security staff, with 37.5% for nurses and 20.9% for administrative staff. Compared to administrative staff, aORs (95% CIs) for seropositivity were 2.54 (1.64-3.94) for nurses; 2.51 (1.42-4.43) for nonclinical HCWs; between 1.70 and 1.83 for allied HCWs such as patient care technicians, social workers, registration clerks and therapists; and 0.80 (0.50-1.29) for physicians. Compared to office locations, aORs for the emergency department and inpatient units were 2.27 (1.53-3.37) and 1.48 (1.14-1.92), respectively. CONCLUSION: One-third of hospital-based HCWs were seropositive for SARS-CoV-2 by the end of the first wave in NYC. Seroprevalence differed by job function and work location, with the highest estimated risk for nurses and the emergency department, respectively. These findings support current nationwide policy prioritizing HCWs for receipt of newly authorized COVID-19 vaccines.


Asunto(s)
COVID-19/epidemiología , Personal de Salud/estadística & datos numéricos , Hospitales de Enseñanza/estadística & datos numéricos , Ocupaciones/estadística & datos numéricos , Adolescente , Adulto , Anciano , COVID-19/inmunología , Estudios Transversales , Femenino , Humanos , Control de Infecciones , Masculino , Persona de Mediana Edad , Ciudad de Nueva York/epidemiología , SARS-CoV-2 , Estudios Seroepidemiológicos , Lugar de Trabajo/estadística & datos numéricos , Adulto Joven
13.
Artículo en Inglés | AIM (África) | ID: biblio-1259201

RESUMEN

Context: Sexual assault is a crime of violence that incorporates unwanted sexual behaviour, such as sexual coercion, uninvited kissing, fondling, touching and ultimately, rape. Individuals prone to sexual abuse are usually the young, poor, and vulnerable members of society, who are often subject to other forms of social vices, such as domestic violence. Aims: To ascertain the pattern of sexual assault in people presenting to a large gynaecological unit of a tertiary referral centre, in Nigeria. Settings and Design: Methods and Material: The study is a descriptive cross-sectional study that was undertaken over a 2-year period from January 2011 to December 2012. Statistical analysis used: SPSS. Results: The prevalence of sexual assault in this study was 1.64%. The majority (90.3%) of victims were single. At least a third (n=35) had secondary education. 62.65% of the patients delayed presentation until after 24hours, (n=52). The commonest reason for delay in presentation was of fear or embarrassment in 51.80% (n=43). The commonest place of assault was at the assailant's home in 33.7% (n=28). Many cases of assault occurred at night. 63.65% of the victims wanted suspects to be prosecuted (n=53). 67.46% of the victims expressed the desire to take legal action (n=56). Only 51.80% of the respondents (n=43) were aware of a route of seeking re-dress. Conclusions: Victims of sexual assault delay their presentation to health facilities because of fear and embarrassment. A significant percentage of the victims do not know how to obtain medical help


Asunto(s)
Víctimas de Crimen , Violencia Doméstica , Nigeria , Delitos Sexuales , Conducta Sexual
14.
Front Plant Sci ; 7: 1336, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27660631

RESUMEN

Plants often experience various biotic and abiotic stresses during their life cycle. The abiotic stresses include mainly drought, salt, temperature (low/high), flooding and nutritional deficiency/excess which hamper crop growth and yield to a great extent. In view of a projection 50% of the crop loss is attributable to abiotic stresses. However, abiotic stresses cause a myriad of changes in physiological, molecular and biochemical processes operating in plants. It is now widely reported that several proteins respond to these stresses at pre- and post-transcriptional and translational levels. By knowing the role of these stress inducible proteins, it would be easy to comprehensively expound the processes of stress tolerance in plants. The proteomics study offers a new approach to discover proteins and pathways associated with crop physiological and stress responses. Thus, studying the plants at proteomic levels could help understand the pathways involved in stress tolerance. Furthermore, improving the understanding of the identified key metabolic proteins involved in tolerance can be implemented into biotechnological applications, regarding recombinant/transgenic formation. Additionally, the investigation of identified metabolic processes ultimately supports the development of antistress strategies. In this review, we discussed the role of proteomics in crop stress tolerance. We also discussed different abiotic stresses and their effects on plants, particularly with reference to stress-induced expression of proteins, and how proteomics could act as vital biotechnological tools for improving stress tolerance in plants.

15.
Front Plant Sci ; 7: 513, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27200003

RESUMEN

This work examined the role of exogenously applied calcium (Ca; 50 mM) and potassium (K; 10 mM) (alone and in combination) in alleviating the negative effects of cadmium (Cd; 200 µM) on growth, biochemical attributes, secondary metabolites and yield of chickpea (Cicer arietinum L.). Cd stress significantly decreased the length and weight (fresh and dry) of shoot and root and yield attributes in terms of number of pods and seed yield (vs. control). Exhibition of decreases in chlorophyll (Chl) a, Chl b, and total Chl was also observed with Cd-exposure when compared to control. However, Cd-exposure led to an increase in the content of carotenoids. In contrast, the exogenous application of Ca and K individually as well as in combination minimized the extent of Cd-impact on previous traits. C. arietinum seedlings subjected to Cd treatment exhibited increased contents of organic solute (proline, Pro) and total protein; whereas, Ca and K-supplementation further enhanced the Pro and total protein content. Additionally, compared to control, Cd-exposure also caused elevation in the contents of oxidative stress markers (hydrogen peroxidase, H2O2; malondialdehyde, MDA) and in the activity of antioxidant defense enzymes (superoxide dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX; glutathione reductase, GR). Ca, K, and Ca + K supplementation caused further enhancements in the activity of these enzymes but significantly decreased contents of H2O2 and MDA, also that of Cd accumulation in shoot and root. The contents of total phenol, flavonoid and mineral elements (S, Mn, Mg, Ca and K) that were also suppressed in Cd stressed plants in both shoot and root were restored to appreciable levels with Ca- and K-supplementation. However, the combination of Ca + K supplementation was more effective in bringing the positive response as compared to individual effect of Ca and K on Cd-exposed C. arietinum. Overall, this investigation suggests that application of Ca and/or K can efficiently minimize Cd-toxicity and eventually improve health and yield in C. arietinum by the cumulative outcome of the enhanced contents of organic solute, secondary metabolites, mineral elements, and activity of antioxidant defense enzymes.

16.
Front Plant Sci ; 7: 347, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27066020

RESUMEN

This work was designed to evaluate whether external application of nitric oxide (NO) in the form of its donor S-nitroso-N-acetylpenicillamine (SNAP) could mitigate the deleterious effects of NaCl stress on chickpea (Cicer arietinum L.) plants. SNAP (50 µM) was applied to chickpea plants grown under non-saline and saline conditions (50 and 100 mM NaCl). Salt stress inhibited growth and biomass yield, leaf relative water content (LRWC) and chlorophyll content of chickpea plants. High salinity increased electrolyte leakage, carotenoid content and the levels of osmolytes (proline, glycine betaine, soluble proteins and soluble sugars), hydrogen peroxide (H2O2) and malondialdehyde (MDA), as well as the activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase in chickpea plants. Expression of the representative SOD, CAT and APX genes examined was also up-regulated in chickpea plants by salt stress. On the other hand, exogenous application of NO to salinized plants enhanced the growth parameters, LRWC, photosynthetic pigment production and levels of osmolytes, as well as the activities of examined antioxidant enzymes which is correlated with up-regulation of the examined SOD, CAT and APX genes, in comparison with plants treated with NaCl only. Furthermore, electrolyte leakage, H2O2 and MDA contents showed decline in salt-stressed plants supplemented with NO as compared with those in NaCl-treated plants alone. Thus, the exogenous application of NO protected chickpea plants against salt stress-induced oxidative damage by enhancing the biosyntheses of antioxidant enzymes, thereby improving plant growth under saline stress. Taken together, our results demonstrate that NO has capability to mitigate the adverse effects of high salinity on chickpea plants by improving LRWC, photosynthetic pigment biosyntheses, osmolyte accumulation and antioxidative defense system.

17.
Front Plant Sci ; 7: 243, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27014283

RESUMEN

Silicon (Si) has been known to augment plant defense against biotic and abiotic pressures. Maize (Zea maize L.) is classified as a Si accumulator and is relatively susceptible to alkaline stress. In this study, seeds of maize were grown in pots and exposed to various concentrations of Na2CO3 (0, 25, 50, and 75 mM) with or without 1.5 mM Si in the form of sodium metasilicate Na2O3Si.5H2O for 25 days. Alkaline-stressed plants showed a decrease in growth parameters, leaf relative water content (LRWC), and the contents of photosynthetic pigments, soluble sugars, total phenols and potassium ion (K(+)), as well as potassium/sodium ion (K(+)/Na(+)) ratio. By contrast, alkaline stress increased the contents of soluble proteins, total free amino acids, proline, Na(+) and malondialdehyde (MDA), as well as the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in stressed plants. On the other hand, application of Si by seed-priming improved growth of stressed plants, which was accompanied by the enhancement in LRWC, and levels of photosynthetic pigments, soluble sugars, soluble proteins, total free amino acids and K(+), as well as activities of SOD, CAT, and POD enzymes. Furthermore, Si supplement resulted in a decrease in the contents of proline, MDA and Na(+), which together with enhanced K(+) level led to a favorable adjustment of K(+)/Na(+) ratio, in stressed plants relative to plants treated with alkaline stress alone. Taken together, these results indicate that Si plays a pivotal role in alleviating the negative effects of alkaline stress on maize growth by improving water status, enhancing photosynthetic pigments, accumulating osmoprotectants rather than proline, activating the antioxidant machinery, and maintaining the balance of K(+)/Na(+) ratio. Thus, our findings demonstrate that seed-priming with Si is an efficient strategy that can be used to boost tolerance of maize plants to alkaline stress.

18.
Materials (Basel) ; 9(3)2016 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-28773288

RESUMEN

The mechanical behavior of aluminum hexagonal honeycombs subjected to out-of-plane dynamic indentation and compression loads has been investigated numerically using ANSYS/LS-DYNA in this paper. The finite element (FE) models have been verified by previous experimental results in terms of deformation pattern, stress-strain curve, and energy dissipation. The verified FE models have then been used in comprehensive numerical analysis of different aluminum honeycombs. Plateau stress, σpl, and dissipated energy (EI for indentation and EC for compression) have been calculated at different strain rates ranging from 10² to 104 s-1. The effects of strain rate and t/l ratio on the plateau stress, dissipated energy, and tearing energy have been discussed. An empirical formula is proposed to describe the relationship between the tearing energy per unit fracture area, relative density, and strain rate for honeycombs. Moreover, it has been found that a generic formula can be used to describe the relationship between tearing energy per unit fracture area and relative density for both aluminum honeycombs and foams.

19.
Sensors (Basel) ; 15(3): 4749-65, 2015 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-25730480

RESUMEN

A double SAW resonator system was developed as a novel method for gas sensing applications. The proposed system was investigated for hydrogen sensing. Commercial Surface Acoustic Wave (SAW) resonators with resonance frequencies of 433.92 MHz and 433.42 MHz were employed in the double SAW resonator system configuration. The advantages of using this configuration include its ability for remote measurements, and insensitivity to vibrations and other external disturbances. The sensitive layer is composed of functionalized multiwalled carbon nanotubes and polyaniline nanofibers which were deposited on pre-patterned platinum metal electrodes fabricated on a piezoelectric substrate. This was mounted into the DSAWR circuit and connected in parallel. The sensor response was measured as the difference between the resonance frequencies of the SAW resonators, which is a measure of the gas concentration. The sensor showed good response towards hydrogen with a minimum detection limit of 1%.

20.
J Mol Model ; 20(3): 2156, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24567162

RESUMEN

5' Nucleotidase (5' NUC) is a ubiquitously distributed enzyme known to be present in snake venoms (SV) that is responsible primarily for causing dysregulation of physiological homeostasis in humans by inducing anticoagulant effects and by inhibiting platelet aggregation. It is also known to act synergistically with other toxins to exert a more pronounced anti-coagulant effect during envenomation. Its structural and functional role is not yet ascertained clearly. The 3D structure of snake venom 5' nucleotidase (SV-5' NUC) is not yet known and was predicted by us for the first time using a comparative homology modeling approach using Demansia vestigiata protein sequence. The accuracy and stability of the predicted SV-5' NUC structure were validated using several computational approaches. Key interactions of SV-5' NUC were studied using experimental studies/molecular docking analysis of the inhibitors vanillin, vanillic acid and maltol. All these inhibitors were found to dock favorably following pharmacologically relevant absorption, distribution, metabolism and excretion (ADME) profiles. Further, atomic level docking interaction studies using inhibitors of the SV-5' NUC active site revealed amino acid residues Y65 and T72 as important for inhibitor-(SV-5' NUC) interactions. Our in silico analysis is in good agreement with experimental inhibition results of SV-5' NUC with vanillin, vanillic acid and maltol. The present study should therefore play a guiding role in the experimental design of new SV-5' NUC inhibitors for snake bite management. We also identified a few pharmacophoric features essential for SV-5' NUC inhibitory activity that can be utilized further for the discovery of putative anti-venom agents of therapeutic value for snake bite management.


Asunto(s)
5'-Nucleotidasa/química , Simulación de Dinámica Molecular , Estructura Terciaria de Proteína , Venenos de Serpiente/enzimología , 5'-Nucleotidasa/genética , 5'-Nucleotidasa/metabolismo , Secuencia de Aminoácidos , Animales , Benzaldehídos/química , Benzaldehídos/metabolismo , Sitios de Unión , Ligandos , Datos de Secuencia Molecular , Estructura Molecular , Unión Proteica , Mapeo de Interacción de Proteínas , Estructura Secundaria de Proteína , Pironas/química , Pironas/metabolismo , Homología de Secuencia de Aminoácido , Electricidad Estática , Ácido Vanílico/química , Ácido Vanílico/metabolismo
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