Part Of Present Study Research Articles

IMPROVEMENT OF SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUNDS BY JOINT HYBRIDIZATION WITH SMALL AMOUNTS OF SECONDARY FILLERS AND POLYMERS

ABSTRACTTo improve the properties of silica-reinforced truck tire tread compounds, especially abrasion resistance, the effect of vinyl contents in butadiene rubber (BR) or solution styrene–butadiene rubber (SSBR) as secondary polymers in silica-filled natural rubber (NR) compounds at a ratio of 80/20 phr is investigated in the first part of this study. By increasing the levels of vinyl contents in BR in combination with NR, a better Payne effect, 300% modulus, reinforcement index, and tan delta at −20 and 0 ° C are obtained, whereas the tensile strength, elongation at break, and DIN abrasion resistance index decrease with increasing vinyl contents. Higher vinyl contents in SSBR result in improvements in Payne effect, 300% modulus, tan delta at −20 and 0 °C but only a small improvement in DIN abrasion resistance index. Combinations of secondary fillers and polymers in silica-filled NR are covered in the second part of present study. Silica/carbon black–filled NR/BR and NR/SSBR, respectively, and silica/organoclay–filled NR/BR and NR/SSBR show positive effects on scorch time and optimum cure time, with only slight changes in Payne effect, tensile properties, tan delta at −20 and 0 ° C and DIN abrasion resistance as compared with compounds with carbon black N134. The use of organoclay results in an enhanced Payne effect and tan delta at 60 °C, indicative of reduced filler–filler networking and consequently a lower rolling resistance of tire tread compounds as compared with the compound without organoclay. The specific combination of a small amount of organoclay replacing the same amount of silica, together with some of the NR replaced by high-vinyl BR, promises a substantial overall boost in wet and ice traction, abrasion, and wear resistance as compared with straight NR/silica tire treads. This new observation helps to overcome one of the main shortcomings of NR/silica compounds: their generally low wear resistance.

Processos de internacionalização

O artigo apresenta parte de estudos desenvolvidos em projeto de mestrado e de Iniciação científica, no âmbito do NEPPES – Núcleo de Estudos em Políticas e Processos de Educação Superior e também no âmbito do GIEPES – Grupo Internacional de Estudos e Pesquisas em Educação Superior e discute os espaços de internacionalização vividos pela URI – Universidade Regional Integrada do Alto Uruguai e das Missões – localizada na região Noroeste do Estado do Rio Grande do Sul – Brasil. Em seus apontamentos, traz as marcas de uma Instituição comunitária, sem fins lucrativos, que nasce de um projeto sonhado e construído por sua comunidade. Nessa perspectiva, a construção dos processos de internacionalização configura-se como grandes desafios, de um lado, e conquistas muito significativas, por outro. A perspectiva do intercâmbio discente e docente, assim como a possibilidade de participação em grupos de pesquisa nacionais e internacionais, passando por ações de extensão e ensino, tem desafiado a URI a construir possibilidades de internacionalização que vem nascendo a partir dos convívios e contatos docentes com seus pares, dando vida a convênios com inúmeras instituições de diversos países.

Herbal Medicine for Oligomenorrhea and Amenorrhea: A Systematic Review of Ancient and Conventional Medicine.

Introduction Menstrual bleeding cessation is one of the most frequent gynecologic disorders among women in reproductive age. The treatment is based on hormone therapy. Due to the increasing request for alternative medicine remedies in the field of women's diseases, in present study, it was tried to overview medicinal plants used to treat oligomenorrhea and amenorrhea according to the pharmaceutical textbooks of traditional Persian medicine (TPM) and review the evidence in the conventional medicine. Methods This systematic review was designed and performed in 2017 in order to gather information regarding herbal medications of oligomenorrhea and amenorrhea in TPM and conventional medicine. This study had several steps as searching Iranian traditional medicine literature and extracting the emmenagogue plants, classifying the plants, searching the electronic databases, and finding evidences. To search traditional Persian medicine references, Noor digital library was used, which includes several ancient traditional medical references. The classification of plants was done based on the repetition and potency of the plants in the ancient literatures. The required data was gathered using databases such as PubMed, Scopus, Google Scholar, Cochrane Library, Science Direct, and web of knowledge. Results In present study of all 198 emmenagogue medicinal plants found in TPM, 87 cases were specified to be more effective in treating oligomenorrhea and amenorrhea. In second part of present study, where a search of conventional medicine was performed, 12 studies were found, which had 8 plants investigated: Vitex agnus-castus, Trigonella foenum-graecum, Foeniculum vulgare, Cinnamomum verum, Paeonia lactiflora, Sesamum indicum, Mentha longifolia, and Urtica dioica. Conclusion. Traditional Persian medicine has proposed many different medicinal plants for treatment of oligomenorrhea and amenorrhea. Although just few plants have been proven to be effective for treatment of menstrual irregularities, the results and the classification in present study can be used as an outline for future studies and treatment.

Analysis of thin-walled steel beams retrofitted by bonding GFRP stiffeners: Numerical model and investigation of design parameters

Enhancing the load capacity of aged and deficient thin-walled steel structures can be accomplished by increasing member stiffness in buckling prone regions. The literature shows that composite materials have become a major player in retrofitting applications. A new strengthening concept, Strengthening-by-Stiffening (SBS), is applied to buckling prone web panels in thin walled steel beams by bonding pultruded glass fiber reinforced polymer (GFRP) sections. The first part of present study is focused on the construction of a finite element (FE) model for accurate simulation of experimentally obtained results. Initial imperfections, material non-linearity, interlaminar fracture law to simulate adhesive debonding, and GFRP rupture or delamination are accounted for in the construction of the FE model. The second part of the study was focused on parametric studies using the validated FE model to investigate different GFRP sizes, contact areas, panel aspect ratio and slenderness of the web panels on steel beam with SBS retrofitting. Results from the parametric study were used to establish some limits to assist in SBS design. Finally, possible use of SBS strengthening method in new construction was investigated by substituting all steel stiffeners with bonded composite GFRP stiffeners for the improvement of fatigue related behavior that is known to start at the weld toes of steel stiffeners.

Towards the Selection of Superior Sesame Lines Based on Genetic and Phenotypic Characterisation for Uganda

Understanding agricultural biodiversity is critical to formulate breeding strategies for crop improvement and it impacts both, conservation and collection activities. Especially germplasm collections serve as valuable resources, thus, their adequate characterisation is of utmost importance. Although Uganda ranks seventh in African sesame production, meagre research was conducted to determine the current genetic diversity among its germplasm. Therefore, in the present study part of the sesame germplasm conserved at the National Semi-Arid Resources Research Institute (NaSARRI) in Uganda focusing on 85 established lines was genetically and phenotypically characterised. Population genetic and structure analyses revealed rather a low extend of genetic diversity (expected heterozygosity [HE], or gene diversity [D]) ranging from 0 to 0.38 per entry, but a high extend of admixture within and between entries. This decrease of heterozygosity is supported by a fixation index (FST) of 0.530, indicating a medium genetic differentiation among entries. The analysis of quantitative and qualitative agromorphological traits revealed a great inter-trait variability among the entries and further indicated a certain conservation of some of the traits reflecting the geographic origin of the analysed entries. Based on both, the genetic and phenotypic characterisation, a selection of 26 superior entries is proposed, which may form a valuable basis both for farmers and breeders.

Inhibition of Intermediate-Conductance Calcium-Activated K Channel (KCa3.1) and Fibroblast Mitogenesis by α-Linolenic Acid and Alterations of Channel Expression in the Lysosomal Storage Disorders, Fabry Disease, and Niemann Pick C.

The calcium/calmodulin-gated KCa3.1 channel regulates normal and abnormal mitogenesis by controlling K+-efflux, cell volume, and membrane hyperpolarization-driven calcium-entry. Recent studies suggest modulation of KCa3.1 by omega-3 fatty acids as negative modulators and impaired KCa3.1 functions in the inherited lysosomal storage disorder (LSD), Fabry disease (FD). In the first part of present study, we characterize KCa3.1 in murine and human fibroblasts and test the impact of omega-3 fatty acids on fibroblast proliferation. In the second, we study whether KCa3.1 is altered in the LSDs, FD, and Niemann-Pick disease type C (NPC). Our patch-clamp and mRNA-expression studies on murine and human fibroblasts show functional expression of KCa3.1. KCa currents display the typical pharmacological fingerprint of KCa3.1: Ca2+-activation, potentiation by the positive-gating modulators, SKA-31 and SKA-121, and inhibition by TRAM-34, Senicapoc (ICA-17043), and the negative-gating modulator, 13b. Considering modulation by omega-3 fatty acids we found that α-linolenic acid (α-LA) and docosahexanenoic acid (DHA) inhibit KCa3.1 currents and strongly reduce fibroblast growth. The α-LA-rich linseed oil and γ-LA-rich borage oil at 0.5% produce channel inhibition while α-LA/γ-LA-low oils has no anti-proliferative effect. Concerning KCa3.1 in LSD, mRNA expression studies, and patch-clamp on primary fibroblasts from FD and NPC patients reveal lower KCa3.1-gene expression and membrane expression than in control fibroblasts. In conclusion, the omega-3 fatty acid, α-LA, and α-LA/γ-LA-rich plant oils, inhibit fibroblast KCa3.1 channels and mitogenesis. Reduced fibroblast KCa3.1 functions are a feature and possible biomarker of cell dysfunction in FD and NPC and supports the concept that biased lipid metabolism is capable of negatively modulating KCa3.1 expression.

Influence of Shape, Number, and Position of Horizontal Minifins on Thermal-Hydraulic Performance of Minichannel Heat Sink Using Nanofluid

ABSTRACTIn the first part of present study, an experimental setup with constant heat flux is used to investigate the thermal performance of the water inside a horizontal triangular pin fin channel. For the sake of validation of the computational fluid dynamics (CFD) study, a simulation is conducted according to the geometry and operating conditions of the experimental work. The numerical model consists of a study that has been established based on the geometrical parameters and operating conditions similar to the experimental work. The influence of four different cross sections of minifins (shaped as square, trapezoidal, triangular, and sinusoidal) and of number of triangular minifins (1, 3, 5, 7, and 9) and their positions (in the regions of entrance, central, and terminal) on the heat transfer rate and pressure drop in a minifin minichannel heat sink are numerically investigated by a two-dimensional CFD model. The coolant is Cu–water nanofluid at a volumetric concentration of 2%. The results demonstrated that the sinusoidal minifin minichannel heat sink has the highest convective heat transfer coefficient in comparison with other shapes, while the trapezoidal minifin minichannel showed the highest thermal resistance. The highest pressure drop was observed for the triangular minifin inside minichannel. By increasing the number of fins, thermal resistance considerably decreased. Likewise, at the central and entrance positions, respectively, the highest Nusselt number and friction factor inside the minichannel was observed. This study can provide useful guidelines for the design of the cooling devices.

Effect of Thiosulfate on Pitting Corrosion of 316SS: II. Metastable Pitting and Transition to Stability

In the present part of study, the effect of thiosulfate ion on pitting corrosion of AISI 316 stainless steel in 0.1 M NaCl solution was investigated. In order to elucidate the effect of thiosulfate on pitting corrosion, the metastable pitting has been studied in more details. The results showed that the thiosulfate addition increased susceptibility to pit initiation and increased the dissolution kinetics of metastable growing pits in a fashion that facilitates the transition from metastability to stability. Consequently, the pitting potential of the stainless steel was decreased in the presence of thiosulfate ion.

Zinc deficiency induces behavioral alterations in the tail suspension test in mice. Effect of antidepressants

BackgroundRecently, experimental zinc deficiency has been correlated with depression-like alterations in rodents. MethodsIn the first part of present study, the time course of zinc deficient diet induced alterations in the tail suspension test (TST) in mice was investigated. In the second part, the effect of imipramine and escitalopram in control and zinc-deprived for 3 weeks mice was examined in the TST. ResultsA 4- and 10-week administration of a Zn-deficient diet enhanced the immobility time in the TST (by 20% and 57%, respectively). By contrast, a 2-week period of a zinc deficient diet effected the reduction (by 24%) of the immobility time. Moreover, a 2- and 4-week (but not 10-week) of a Zn-deficient diet resulted in the reduction of the body weight (by 37% and 18%, respectively). These results indicate the developing response to zinc deficiency induced by a zinc-deficient diet. The antidepressant-like effect (reduction in the immobility time) of both drugs was significantly reduced in zinc-deprived mice, which suggests treatment-resistance induced by zinc deprivation. ConclusionsZinc deprivation induces “pro-depressive” behavior and alters antidepressant efficacy.

Initial pregnancies after intravaginal transport and partial zona dissection of human ova

We report on 72 couples with previous failure of fertilisation during several trials of conventional in-vitro fertilisation (IVF). In the present study part of the aspirated oocytes was subjected to partial zona dissection (PZD) before insemination, thereby achieving 7 pregnancies during 104 cycles. Normal in-vitro insemination of the remaining zona-intact oocytes was again unsuccessful. Since microinsemination techniques, in contrast to conventional IVF, are not yet being offered by many clinics, we developed the following new concept: hormonal stimulation, sonographic control of follicular growth, aspiration of oocytes, and sperm preparation were performed at the usual place (Munich) whereas PZD and control IVF were accomplished in another laboratory (Ulm). In order to transport the gametes between these two institutes, we modified the previously reported intravaginal culture (IVC) of inseminated oocytes by transferring oocytes and spermatozoa into separate plastic capsules. In our view, this procedure offers a suitable opportunity for infertile couples living too far away from a microinsemination centre to afford long daily journeys or even several overnight stays for superovulation treatment. The fertilisation and pregnancy rates in our study are comparable to those reported in the literature.