Antiferromagnetic spin chain behavior and a transition to 3D magnetic order in Cu(D,L-alanine)2: Roles of H-bonds

We study the spin chain behavior, a transition to 3D magnetic order and the magnitudes of the exchange interactions for the metal-amino acid complex Cu(D,L-alanine)2.H2O, a model compound to investigate exchange couplings supported by chemical paths characteristic of biomolecules. Thermal and magnetic data were obtained as a function of temperature (T) and magnetic field (B0). The magnetic contribution to the specific heat, measured between 0.48 and 30 K, displays above 1.8 K a 1D spin-chain behavior that can be fitted with an intrachain antiferromagnetic (AFM) exchange coupling constant 2J0 = (-2.12 $\pm$ 0.08) cm$^{-1}$, between neighbor coppers at 4.49 {\AA} along chains connected by non-covalent and H-bonds. We also observe a narrow specific heat peak at 0.89 K indicating a phase transition to a 3D magnetically ordered phase. Magnetization curves at fixed T = 2, 4 and 7 K with B0 between 0 and 9 T, and at T between 2 and 300 K with several fixed values of B0 were globally fitted by an intrachain AFM exchange coupling constant 2J0 = (-2.27 $\pm$ 0.02) cm$^{-1}$ and g = 2.091 $\pm$ 0.005. Interchain interactions J1 between coppers in neighbor chains connected through long chemical paths with total length of 9.51 {\AA} are estimated within the range 0.1 < |2J1| < 0.4 cm$^{-1}$, covering the predictions of various approximations. We analyze the magnitudes of 2J0 and 2J1 in terms of the structure of the corresponding chemical paths. The main contribution in supporting the intrachain interaction is assigned to H-bonds while the interchain interactions are supported by paths containing H-bonds and carboxylate bridges, with the role of the H-bonds being predominant. We compare the obtained intrachain coupling with studies of compounds showing similar behavior and discuss the validity of the approximations allowing to calculate the interchain interactions.Comment: 10 pages, 4 figure

Opportunistic Infections and Associated Factors among HIV Infected Patients on Anti-Retroviral Treatment at Bombo Hospital in Tanga Region, Tanzania

Background: A substantive number of People Living with HIV (PLHIV) develop Opportunistic Infections (OIs). The introduction of Anti-Retroviral Therapy (ART) in Tanzania led to a significant decline in opportunistic infections and a slower progression to AIDS, but OIs are still prevalent. This study was set to determine the magnitude of OIs and associated factors among HIV/AIDS patients on Anti-Retroviral Therapy (ART) attending care and treatment clinic at Bombo Regional Referral hospital, Tanga region. Materials and Methods: A cross‐sectional descriptive study was conducted on HIV/AIDS patients on ART attending Bombo Hospital in Tanga from July to October 2019. A non-probability, consecutive sampling technique was employed to obtain study participants. Data were collected using available data obtained from the patients’ files, hospital record books and interviews of study participants by using semi-structured questionnaires. Data were entered into the computer using Excel 2013, cleaned and analysed using Epi Info version 7.2.2.6. Any p-value of &lt; 0.05, at a 95% confidence interval was regarded as statistically significant. Results: The study showed that out of the 360 participants, 126 cases (35.0%) of OIs were reported. Pulmonary Tuberculosis had the highest prevalence of 18.0% among PLHIV while other opportunistic Infections altogether contributed 17.0%. Late ART initiation (OR=10.9, 95% CI: 6.5 – 18.3, p-value &lt;0.001), Poor drug adherence (OR=19, 95% CI: 9.0 – 39.7, p-value &lt;0.001), female gender (69% vs. 31%), which was however, not statistically significant (p-value – 0.904), Informal and Primary School education (OR = 1.6, 95% CI: 1.1 – 1.6, p-value 0.04) being married (OR=2.1, 95% CI: 1.3 – 3.4, p – value 0.004) and widowed/widower (OR=7.7, 95% CI: 1.7 – 33.7, p – value 0.007) respectively were found to be associated with OIs to PLHIV. Conclusion: The rate of OIs still high among PLHIV, Pulmonary Tuberculosis is the leading disease with 18.0% of all OIs symptomatic patients. Delay in ART initiation after positive test results, poor drug adherence and moderate malnutrition have been identified as major risk factors affecting 66.0%, 70.0%, 71%of PLWHA with OIs. We recommend early initiation of ART, Education on ART adherence and refilling of large quantities of ARV drugs to individuals working far from their homes

External marking and behavior of early instar \u3ci\u3eHelicoverpa armigera\u3c/i\u3e (Lepidoptera: Noctuidae) on soybean

Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a pest of major agricultural crops, such as soybean and cotton. A better understanding of larval movement is important for its integrated management and resistance management. Studies with neonates through second instar larvae are still limited by the difficulties involving the handling and observation of these instars. Many studies require marking larvae, and most research involving marking is focused on moths. However, our study investigated aspects of larval behavior of the second instar of H. armigera on soybean plants. The dyes luminous powder red and Sudan Red 7B were tested as external larval markers. Both dyes successfully marked the larvae for most of 1 stadium (48 h) without deleterious effects, and are useful for short-period behavioral studies. Luminous powder red was selected for the H. armigera larval behavior study on soybean because of ease of detection during both day and night. Second instar on-plant movement was consistent, independent of the d period (morning, afternoon, evening). In general, larvae established their feeding site within a few hours of release, and remained feeding on soybean leaves. Second instar behavior suggests that management by nocturnal insecticide application, based on H. armigera larval movement, would not have an advantage over daytime application. Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) está entre as principais pragas de importancia para culturas agrícolas, como soja e algodão. Compreender o comportamento larval desta espécie, principalmente durante os estádios iniciais é de suma importância para seu manejo integrado e para o manejo de populações resistentes. No entanto, pesquisas com neonatas ou lagartas de segundo ínstar são limitadas devido às dificuldades envolvendo o manuseio e observação de insetos tão diminutos. Muitos desses estudos requerem a marcação de indivíduos, e até o momento, a maioria das pesquisas com marcação de insetos é focada em adultos. Assim, nosso estudo investigou aspectos do comportamento de lagartas de segundo instar de H. armigera em plantas de soja. Estudos prévios também foram realizados com o intuito de se avaliar métodos alternativos e eficazes para marcação de estádios iniciais das larvas desse noctuídeo e suas aplicações em estudos de comportamento. Para tanto, os corantes luminous powder (azul e vermelho) e Sudan (azul e vermelho 7B) foram testados por meio da incorporação em dieta artifical e polvilhamento sobre as lagartas. Baseado em nossos ensaios prévios de laboratório, os corantes incorporados na dieta artifical apresentaram efeitos variáveis sobre os parâmetros biológicos de H. armigera e baixa persistência após o segundo ínstar. Os corantes aplicados por polvilhamento marcaram com sucesso as lagartas e luminous powder vermelho foi selecionado para o estudo de comportamento de lagartas de segundo ínstar em plantas de soja. Lagartas de segundo ínstar apresentaram comportamento de movimento nas plantas semelhantes, independentemente do período de avaliação (manhã, tarde e noite). Em geral, a maioria das lagartas estabeleceram seu sítio de alimentação após algumas horas e permaneceram se alimentando sobre as folhas de soja. Os resultados de comportamento de larvas de H. armigera em segundo instar, documentado no presente trabalho, indicam que aplicacões noturnas de insecticidas não representa vantagem para aumento da eficiência de controle, quando comparado com aplicacões de inseticidas durante o dia

Bulbos úmidos a partir da irrigação por gotejamento subsuperficial com água de abastecimento e efluente de esgoto tratado

The use of treated sewage effluent (TSE) combined with the subsurface drip irrigation (SDI) method in agriculture can decrease the costs of agricultural production, in attempts to fertigate crops more efficiently. In this study it was compared the dimensions of the wet bulb formed by the application of TSE and municipal water supply (MWS) in an Oxisoil. We have evaluated the effect of water quality and discharge between drippers used in sugarcane crop. Three trenches were opened and 21 three-rod TDR probes were setup in a mesh and a dripper was buried at 0.30 m, for each constant discharge of 1.0 L h-1and 1.6 L h-1. Comparing results from different wetted soil profiles it was observed that the vertical and horizontal dimensions of the wet bulb are similar for both MWS and TSE, being peculiars according to the discharges used and volume applied. Regardless the water quality, an increase of 60% in discharge decreased the deepest infiltration.352242253O uso de efluente de esgoto tratado (EET), combinado com o método de irrigação por gotejamento subsuperfical (IGS) na agricultura, pode reduzir os custos de produção agrícola, fertirrigando de maneira eficiente as culturas. Neste artigo, compararam-se as dimensões do bulbo úmido formado pela aplicação de EET e água de abastecimento municipal (AAM), em um Latossolo Vermelho distroférrico. Avaliou-se o efeito da qualidade da água e da vazão entre gotejadores utilizados na cultura da cana-de-açúcar. Três trincheiras foram abertas e 21 sondas de TDR com três hastes foram instaladas em malha, e um gotejador foi enterrado a 0,30 m, para cada vazão constante de 1,0 Lh-1 e 1,6 Lh-1. Comparando os resultados de diferentes perfis de umidade do solo, sugere-se que as dimensões vertical e horizontal do bulbo úmido sejam similares para a AAM e para o EET, sendo peculiares de acordo com as vazões utilizadas e o volume aplicado. Independentemente da qualidade da água, o aumento de 60% na vazão reduziu a infiltração em profundidade

Time Domain Reflectometry (TDR) calibration for estimating soil solution concentration

Time Domain Reflectometry (TDR) is a reliable method for in-situ measurements of the humidity and the solution concentration at the same soil volume. Accurate interpretation of electrical conductivity (and soil humidity) measurements may require a specific calibration curve. The primary goal of this work was to establish a calibration procedure for using TDR to estimate potassium nitrate concentrations (KNO3) in soil solution. An equation relating the electrical conductivity measured by TDR and KNO3 concentration was established enabling the use of TDR technique to estimate soil water content and nitrate concentration for efficient fertigation management.A Reflectometria no Domínio do Tempo (TDR) é um método confiável para medidas in situ da umidade e da concentração da solução no mesmo volume de solo. Entretanto, a interpretação precisa da medida de condutividade elétrica do solo (e umidade do solo) pode requerer uma curva de calibração específica. O objetivo principal deste ensaio foi estabelecer um procedimento de calibração para usar a TDR no cálculo de concentrações de nitrato de potássio (KNO3) em solução do solo. Uma equação que relaciona a condutividade elétrica medida pela TDR e a concentração de KNO3 foram encontradas viabilizando o uso da técnica da TDR na estimativa da umidade e da concentração da solução do solo para o manejo eficiente da fertirrigação.282291Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Platelet hyperaggregability in high-fat fed rats: A role for intraplatelet reactive-oxygen species production

<p>Abstract</p> <p>Background</p> <p>Adiposity greatly increases the risk of atherothrombotic events, a pathological condition where a chronic state of oxidative stress is reported to play a major role. This study aimed to investigate the involvement of (NO)-soluble guanylyl cyclase (sGC) signaling pathway in the platelet dysfunction from high fat-fed (HFF) rats.</p> <p>Methods</p> <p>Male Wistar rats were fed for 10 weeks with standard chow (SCD) or high-fat diet (HFD). ADP (10 μM)- and thrombin (100 mU/ml)-induced washed platelet aggregation were evaluated. Measurement of intracellular levels of ROS levels was carried out using flow cytometry. Cyclic GMP levels were evaluated using ELISA kits.</p> <p>Results</p> <p>High-fat fed rats exhibited significant increases in body weight, epididymal fat, fasting glucose levels and glucose intolerance compared with SCD group. Platelet aggregation induced by ADP (<it>n </it>= 8) and thrombin from HFD rats (<it>n </it>= 8) were significantly greater (<it>P </it>< 0.05) compared with SCD group. Platelet activation with ADP increased by 54% the intraplatelet ROS production in HFD group, as measured by flow cytometry (<it>n </it>= 6). N-acetylcysteine (NAC; 1 mM) and PEG-catalase (1000 U/ml) fully prevented the increased ROS production and platelet hyperaggregability in HFD group. The NO donors sodium nitroprusside (SNP; 10 μM) and SNAP (10 μM), as well as the NO-independent soluble guanylyl cyclase stimulator BAY 41-2272 (10 μM) inhibited the platelet aggregation in HFD group with lower efficacy (<it>P </it>< 0.05) compared with SCD group. The cGMP levels in response to these agents were also markedly lower in HFD group (<it>P </it>< 0.05). The prostacyclin analogue iloprost (1 μM) reduced platelet aggregation in HFD and SCD rats in a similar fashion (<it>n </it>= 4).</p> <p>Conclusions</p> <p>Metabolic abnormalities as consequence of HFD cause platelet hyperaggregability involving enhanced intraplatelet ROS production and decreased NO bioavailability that appear to be accompanied by potential defects in the prosthetic haem group of soluble guanylyl cyclase.</p

Efecto del tiempo y temperatura de almacenamiento en los parámetros físico-químicos y de color de frutos de aguaymanto (Physalis peruviana)

Los frutos de aguaymanto (Physalis peruviana) son comercializados en fresco, en diversas regiones de Sudamérica y del mundo. No obstante, existen algunos problemas relacionados a la pérdida de calidad, debido al mal manejo del almacenamiento postcosecha. Por ello, este estudio evaluó el efecto del tiempo y temperatura de almacenamiento postcosecha, sobre las propiedades fisicoquímicas e índice de madurez de frutos de aguaymanto. Se utilizó un diseño factorial de dos factores (temperatura y tiempo de almacenamiento). Los frutos de aguaymanto fueron colocados en empaques de polietileno tereftalato perforados y fueron almacenados en oscuridad a 4 °C, 12 °C y 20 °C. Las mediciones de Brix, pH, acidez, índice de madurez y parámetros de color (L*, a*. b*) se realizaron a los 0, 8, 17 y 27 días. Los frutos de aguaymanto que fueron almacenados a bajas temperaturas (4 °C) mostraron una ligera variación en su índice de madurez y presentaron una reducción en los parámetros L* y b* y un incremento del parámetro a* a los 7 días de almacenamiento. Se observó un efecto significativo (p&lt;0.05) del tiempo y temperatura de almacenamiento postcosecha sobre el Brix, pH, acidez, índice de madurez y los parámetros de color de frutos de aguaymanto

Antiplasmodial Properties and Cytotoxicity of Endophytic Fungi from Symphonia globulifera (Clusiaceae)

Ateba JET, Toghueo RMK, Awantu AF, et al. Antiplasmodial Properties and Cytotoxicity of Endophytic Fungi from Symphonia globulifera (Clusiaceae). JOURNAL OF FUNGI. 2018;4(2): UNSP 70.There is continuing need for new and improved drugs to tackle malaria, which remains a major public health problem, especially in tropical and subtropical regions of the world. Natural products represent credible sources of new antiplasmodial agents for antimalarial drug development. Endophytes that widely colonize healthy tissues of plants have been shown to synthesize a great variety of secondary metabolites that might possess antiplasmodial benefits. The present study was carried out to evaluate the antiplasmodial potential of extracts from endophytic fungi isolated from Symphonia globulifera against a chloroquine-resistant strain of Plasmodium falciparum (PfINDO). Sixty-one fungal isolates with infection frequency of 67.77% were obtained from the bark of S. globulifera. Twelve selected isolates were classified into six different genera including Fusarium, Paecilomyces, Penicillium, Aspergillus, Mucor, and Bipolaris. Extracts from the 12 isolates were tested against PfINDO, and nine showed good activity (IC50 < 10 mu g.mL(-1)) with three fungi including Paecilomyces lilacinus (IC50 = 0.44 mu g.mL(-1)), Penicillium janthinellum (IC50 = 0.2 mu g.mL(-1)), and Paecilomyces sp. (IC50 = 0.55 mu g.mL(-1)) showing the highest promise. These three isolates were found to be less cytotoxic against the HEK293T cell line with selectivity indices ranging from 24.52 to 70.56. Results from this study indicate that endophytic fungi from Symphonia globulifera are promising sources of hit compounds that might be further investigated as novel drugs against malaria. The chemical investigation of active extracts is ongoing