Brownian motion of single glycerol molecules in an aqueous solution as studied by dynamic light scattering

Aqueous solutions of glycerol are investigated by dynamic light scattering (DLS) over the whole concentration range (10-98 wt.% water) and in the temperature range 283-303 K. The measurements reveal one slow relaxation process in the geometry of polarized light scattering. This process is present in the whole concentration range, although it is very weak at the highest and lowest water concentrations and is considerably slower than the structural alpha relaxation, which is too fast to be observed on the experimental time scale in the measured temperature range. The relaxation time of the observed process exhibits a 1/q(2) dependence, proving that it is due to long-range translational diffusion. The Stokes-Einstein relation is used to estimate the hydrodynamic radius of the diffusing particles and from these calculations it is evident that the observed relaxation process is due to the Brownian motion of single or a few glycerol molecules. The fact that it is possible to study the self-diffusion of such small molecules may stimulate a broadening of the research field used to be covered by the DLS technique

Sedimentology of the Swift Formation (Jurassic) in the Little Rocky Mountains of Montana

The marine strata of the Swift Formation (Upper Callovian-Oxfordian) are widely distributed and well exposed in the Little Rocky Mountains of north-central Montana. The contact between the Swift and the underlying marine Rierdon Formation is sharp, whereas the upper contact with the non-marine Morrison Formation is gradational. The Swift Formation is about 30 m to 50 m thick and is divided into two members: a lower shale and an upper sandstone. Detailed sedimentological analysis defined six facies; three in each member. The shale member contains a conglomerate facies (Facies A), a shale-siltstone facies (Facies B), and a bioclastic limestone facies (Facies C). The facies of the sandstone member comprise a sandstone­-siltstone-shale facies (Facies D), a cross-bedded sandstone facies (Facies E), and a limestone facies (Facies F). The Swift Formation forms a coarsening-upward sequence from mud to sand-silt-mud intercalations to sand, which has been interpreted by other people as a progradational sequence across a shelf. The Rierdon-Swift contact is a disconformity spanning three ammonite zones. The whole section of the Swift Formation is considered to be a shallow marine shelf deposit that formed in the course of a transgressive-regressive episode during Late Callovian-Oxfordian time. Facies A was produced by the reworking of sediment by waves in a near­shore setting during the early stage of the transgressive sea. Facies B was deposited from suspension in relatively deep, open, marine waters during the maximum expansion of the Oxfordian sea. Facies C was formed by the winnowing effect of frequent storm-generated waves, reworking the muddy platform deposits of Facies B. Facies D and E form a continuous regressive sequence that was deposited in a storm-dominated, lower shoreface environment. Facies F was deposited in a shallow, relatively protected setting. The depositional model proposed for the Swift Formation in the study area is one of a shifting pattern of sedimentation in a shallow marine setting, where inner shelf deposits passed transitionally into lower shoreface deposits; these, in turn, gave way to middle-to-upper shoreface sediments. The sea-level changes during the deposition of the Swift Formation were as a result of mainly local and regional tectonism; eustatic factors, if any, were minor

Regulation of adenovirus replication by miR-199 confers a selective oncolytic activity in hepatocellular carcinoma

Oncolytic virotherapy represents a growing field of experimental cancer therapy. For safe and effective virotherapy, restricted tissue expression and replication of the virus is desirable. Various methods have been developed to achieve such restricted expression. They included the engineering of viral genomes through the insertion of tissue-specific promoters or genes encoding for tissue specific binding proteins. Here, we employed a new approach based on the use of microRNAs (miRNAs) to achieve tumor-specific viral expression and replication. miRNAs are approximately 22-nucleotide (nt)- long non-coding RNAs that are able to bind the 3’ untranslated regions (UTRs) of homologous target mRNAs and causing either their degradation or translation inhibition. Since miRNA are differentially expressed in cancer versus normal cells, it is theoretically possible to make virus expression restricted to cancer cells in a miRNA-dependent manner. Several studies have shown that miR-199 is significantly down-regulated in primary hepatocellular carcinoma (HCC) tissue and HCC cell lines. With this notion in mind, we developed a conditionally replication-competent oncolytic adenovirus, Ad-199T, by introducing four copies of miR-199 target sites within the 3′ UTR of the E1A gene, which is essential for adenovirus replication. In vitro studies of the properties of Ad-199T virus revealed that E1A expression was indeed tightly regulated both at RNA and protein levels depending upon the expression of miR-199. Consequently, Ad-199T could replicate in the HCC derived cells HepG2, negative for miR-199 expression, while its replication was strictly controlled in HepG2-199 cells, which were engineered to express high level of miR-199. A replication-competent miRNA independent Ad-Control was also generated,. Thus, these in vitro studies proved that cytotoxicity of Ad-199T was effective in HCC derived cells, which lacks expression of miR-199, and could be successfully controlled in cells that express miR-199 at high level. To assess in vivo properties of Ad-199T, we tested an orthotopic tumor model. HepG2 cells were implanted in the liver of newborn B6D2 mice. The cells could survive at least one week in this environment, enough for testing in vivo properties of Ad-199T. These studies revealed that intrahepatic delivery of Ad-199T led to virus replication in HepG2 derived xenograft tumors and a faster removal of cancer cells. Conversely, Ad-199T replication was not detected in normal, miR-199 positive, liver parenchyma. These results demonstrate that Ad-199T is a conditionally replicative adenovirus (CRAd) miR-199 dependent, with antitumor activity in vivo. This system allows replication of the oncolytic virus in HCC cells and, at the same time, tightly control replication in normal liver tissues, thus avoiding or reducing hepatotoxicity

Calorimetric and relaxation properties of xylitol-water mixtures

We present the first broadband dielectric spectroscopy (BDS) and differential scanning calorimetry study of supercooled xylitol-water mixtures in the whole concentration range and in wide frequency (10(-2)-10(6) Hz) and temperature (120-365 K) ranges. The calorimetric glass transition, T-g, decreases from 247 K for pure xylitol to about 181 K at a water concentration of approximately 37 wt. %. At water concentrations in the range 29-35 wt. % a plentiful calorimetric behaviour is observed. In addition to the glass transition, almost simultaneous crystallization and melting events occurring around 230-240 K. At higher water concentrations ice is formed during cooling and the glass transition temperature increases to a steady value of about 200 K for all higher water concentrations. This Tg corresponds to an unfrozen xylitol-water solution containing 20 wt. % water. In addition to the true glass transition we also observed a glass transition-like feature at 220 K for all the ice containing samples. However, this feature ismore likely due to ice dissolution [A. Inaba and O. Andersson, Thermochim. Acta, 461, 44 (2007)]. In the case of the BDS measurements the presence of water clearly has an effect on both the cooperative a-relaxation and the secondary beta-relaxation. The a-relaxation shows a non-Arrhenius temperature dependence and becomes faster with increasing concentration of water. The fragility of the solutions, determined by the temperature dependence of the a-relaxation close to the dynamic glass transition, decreases with increasing water content up to about 26 wt. % water, where ice starts to form. This decrease in fragility with increasing water content is most likely caused by the increasing density of hydrogen bonds, forming a network-like structure in the deeply supercooled regime. The intensity of the secondary beta-relaxation of xylitol decreases noticeably already at a water content of 2 wt. %, and at a water content above 5 wt. % it has been replaced by a considerably stronger water (w) relaxation at about the same frequency. However, the similarities in time scale and activation energy between the w-relaxation and the beta-relaxation of xylitol at water contents below 13 wt. % suggest that the w-relaxation is governed, in some way, by the beta-relaxation of xylitol, since clusters of water molecules are rare at these water concentrations. At higher water concentrations the intensity and relaxation rate of the w-relaxation increase rapidly with increasing water content (up to the concentration where ice starts to form), most likely due to a rapid increase of small water clusters where an increasing number of water molecules interacting with other water molecules

Effect of cultivar, packaging treatments and temperature on post-harvest quality of okra

ABSTRACT    Okra is one of the most popular vegetable crops in Sudan. The introduced cultivars such as Pusa Swani and Clemson Spineless have smooth pods and more adapted to the winter conditions of central Sudan. However, the local cultivar, Khartoumia, has hairy pods and not acceptable in international markets. Okra pods are highly perishable and subject to shriveling especially under the hot arid conditions of central Sudan. Therefore, the objective of this study was to determine the effect of packaging and temperature on the shelf life of okra pods of three introduced cultivars. Treatments consisted of three okra cultivars, namely, Clemson Spineless, Pusa Swani and Mahyco (hybrid); packaging treatments consisted of packing okra pods in cartons lined with intact polyethylene film, perforated polyethylene film or in cartons only and storage temperatures were 140C and 320C. Results showed that pods of the  cultivar Mahyco had the lowest weight loss, retained good colour and had the least decay and rot. Packaging of okra pods in intact or perforated polyethylene film and storing at 140C reduced weight loss and resulted in the best pod colour compared to the control. Packaging in perforated polyethylene film and storing at 140C resulted in the lowest incidence of decay and rot and best overall quality of pods. It is recommended to package okra pods in perforated polyethylene film and ship them to markets at 140C

Transport Properties and Local Structure of an Imidazole/Protic Ionic Liquid Mixture Confined in the Mesopores of Hydrophobic Silica

The local structure and the molecular dynamics of an imidazole/protic ionic liquid mixture have been investigated while confined in only ca. 5 nm mesopores of silica particles. The walls of the silica pores were functionalized with trioctyl groups to ensure a hydrophobic character, and a series of hybrid materials with varying liquid-to-silica ratios were investigated. Results from vibrational spectroscopy (both Raman and infrared) indicate that the local ion-ion interactions as well as the nature of hydrogen bonds inside the nanopores are not significantly different from the case of the bulk liquid mixture. Nevertheless, the ionic conductivity decreases rapidly and monotonically with decreasing amount of liquid, while the self-diffusion coefficients measured by pulsed field gradient nuclear magnetic resonance (NMR) show a distinct dependence on composition. The population of molecules outside the particles seems to contribute with an enhanced diffusivity, while the molecules inside the mesopores diffuse at a rate comparable to that observed in the bulk liquid. In addition, when experimentally possible, we have measured higher diffusivities for the exchangeable -NH proton than for any other molecular species, which is indicative of a decoupled proton motion. Results from X-ray scattering, employed to elucidate the local molecular structure, reveal an additional feature characteristic of the nanoconfined state, which is associated with a real space distance of about 3.5 nm. This distance describes a specific molecular organization inside the mesopores and may reflect the formation of a monolayer of the octyl-imidazolium cations self-assembled at the hydrophobic silica surface. Such a local structure would favor the localization of charges, including the exchangeable protons. In addition, the analysis of molar conductivity suggests that a major problem with a low pore filling is the emergence of discontinuities throughout the liquid phase

Conduction mechanism in polymeric membranes based on PEO or PVdF-HFP and containing a piperidinium ionic liquid

Two types of polymer electrolyte membranes were prepared using poly(ethylene oxide) (PEO) and poly(vinylidene difluoride-co-hexafluoropropylene) (PVdF-HFP), with different amounts of the ionic liquid N-methyl-N-propylpiperidinium bis(trifluoromethane-sulfonyl) imide ([PP13][TFSI]) added. The results from differential scanning calorimetry and conductivity measurements show that in the case of PVdF-HFP membranes the glass transition temperature T-g decreases and the room temperature ionic conductivity increases with increasing content of the ionic liquid (up to 60 wt.%). However, in the case of PEO based membranes Tg is less significantly affected and the room temperature ionic conductivity increases only up to 30 wt.% of ionic liquid, beyond which a steady value of about 5.10(-5) S/cm is reached. The results from Raman spectroscopy show that the characteristic vibrational mode of the TFSI anion at similar to 742 cm(-1) is weakly affected in the membranes prepared from PVdF-HFP, whereas for those based on PEO it has a clearer composition dependence. These results suggest ion-ion and ion-polymer interactions of different nature, which together with the different nanomorphologies adopted by PEO and PVdF-HFP, as revealed by X-ray scattering, give rise to different composition dependences of the macroscopically measured ionic conductivity. (C) 2019 The Authors. Published by Elsevier Ltd

Stigma and discrimination among health care providers towards people living with HIV/AIDS (PLWHA)

Stigma and discrimination among medical care providers (MCPs) towards HIV patients is a common observed problem that can compromise effectiveness of prevention and treatment efforts by discouraging individuals from being tested or seeking information on how to protect themselves and others. This research aimed to determine the existence of stigma and discrimination among health care providers towards people living with HIV and AIDS (PLWHA) in River Nile state. A descriptive cross sectional hospital based study conducted in Atbara, Edamer and Berber hospitals. Questionnaire containing six parts covering the personal data, knowledge about HIV, attitude, availability of PPDs and discriminatory practices of MCPs was used. The data was analyzed using the SPSS. Three hundred and nighty participated consisting of 136 doctors, 219 nurses, and 35 midwives. Out of these, 68.2% of participants had overall satisfactory knowledge, 30% had good knowledge, while only 1.8% had poor knowledge. Majority (74.4%) stated that MCPs were discriminatory in their practices towards HIV patients. There wa correlation between common discriminatory practices and total attitude, and availability of PPDs (p<0.05). No correlation between the common discriminatory practices and total knowledge scores

Letterer Siwe Disease (LSD): A Case Report

Background: Letterer–Siwe Disease (LSD) is one of the variants of Langerhans cell histiocytosis (LCH), which is considered as a rare disease that affects many systems in the body; it is characterized by monoclonal migration and proliferation of specific dendritic cells. The disease affects the bones and skin primarily, but can involveother organs as well, or appear as a multi-system disease leading to different clinical manifestations and eventually death. Summary: The authors present a case report of LSD in a two-year-old child from western Sudan, Messeria tribe, who is presented with one and a half-month history of fever, cutaneous ulcers, purprae,scaly crusted scalp, and pallor. His full blood count showed very low Hb with marked reduction of platelets. TWBC was normal. US showed hepatosplenomegaly with lymphadenopathy. A suspicion of sickle cell anemia and leukemia was suggested. He received treatment in his area in the form of antibiotics, skin care, blood transfusion and platelets aggregate without improvement. Patient was referred to Khartoum for further investigations and management. On presentation, a diagnosis of histiocytosis x was suggested depending on the clinical presentation of a general ill health in a child with purpurae, skin ulcers, and a scaly crusted scalp. A skin biopsy, bone marrow aspirate, and a skull x-ray were requested. Bone marrow aspiration showed hyper cellular BM with marked hemophagocytosis. Patient was admitted in a pediatric ward for further general investigations and blood transfusion, but he passed few days later before starting chemotherapy. Usually this is the prognosis of this rare and fatal aggressive form of histiocytosis x. Conclusion: A sick child with fever, anemia, hepatosplenomegaly, scaly scalp, and skin lesions should be investigated for LSD

Effects of Dietary Furazolidone on the Performance of Broiler Chicks under Sudan Conditions

ABSTRACT The present study was conducted to assess the effects of Furazolidone incorporation in broiler feeds under Sudan Conditions. A total of 144 one-day old non sexed chicks of Lohmann breed were used. Experimental chicks were distributed randomly into 4 treatments, each with three replicates (36 birds/treatment and 12 birds/pen as replicate).Four diets were formulated to be isocaloric and isonitrogenous, supplemented with graded levels of furazolidone (0,100, 200, 300 mg/kg feed). Traits studied were feed intake (weight gain), body weight and feed conversion ratio. Results revealed that body weight, weight gain, feed consumption and feed conversion ratio were not significantly at (P ≤0.05) affected by different levels of Furazolidone. Final body weights at slaughter age (7 weeks) was in the range of 1592±45.9-1706±45.9 g. Weekly weight gain was highest in the fifth week (322-391 g/ day). Average weekly feed intake increased with the advance in age and it approach 100 g in the seventh week of age. Total feed conversion ratio was in the range of 2.24±0.05-2.34±0.05.It is concluded that Furazolidone has neither positive nor negative effects on the performance of broiler chicks. It is suggested that this drug can be used in poultry farms were the hygienic and managerial conditions were poor