65 research outputs found

    Some Characteristics And Allopurinol Release Of Carrageenan/ Allopurinol Films Using Polyethylene Oxide As A Dispersion Aid Agent

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    This paper presents the effect of carrageenan (CG) on some characteristics and drug release of allopurinol in the presence of polyethylene oxide (PEO) as a dispersion aid agent. The samples were prepared in film shape by solution method, in which, the content of PEO was changed from 1 wt.% to 5 wt.% and the content of allopurinol was fixed at 10 wt.% in comparison with carrageenan weight. FTIR , FESEM, UV-Vis methods were used to evaluate characterizations and morphology of CG/PEO/allopurinol films

    Geometric nonlinear vibration analysis of steel frames with semi-rigid connections and rigid-zones

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    To obtain an accurate insight into the behavior of the most realistic steel frames, joint flexibility should be allowed for in the analysis. So far, most research work is concentrated on the linear and geometric nonlinear static analysis of steel frames with flexible connections. Very few papers were contributed to the dynamic and vibration analysis of these types of frames. This paper proposes a numerical method for geometric nonlinear vibration analysis of frames with semi-rigid connections and rigid-zones. The effect of initial stress due to the applied load is accounted for in the suggested method, which is believed to be more general than the existing methods and does not involve complex calculations

    A new semislug of the genus Laocaia (Gastropoda, Pulmonata, Helicarionidae) from Vietnam

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    A new species of the genus Laocaia Kuzminykh, 1999, Laocaia simovi Dedov & Schneppat, sp. nov., is described, which was collected from a single locality in northern Vietnam. Color pictures of living specimens are provided. For the first time, information on the ecology and biology of a representative of the genus Laocaia is presented

    Dynamic stiffness method for free vibrations analysis of partial fluid-filled orthotropic circular cylindrical shells

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    Free vibrations of partial fluid-filled orthotropic circular cylindrical shells are investigated using the Dynamic Stiffness Method (DSM) or Continuous Element Method (CEM) based on theFirst Order Shear Deformation Theory (FSDT) and non-viscous incompressible fluid equations. Numerical examples are given for analyzing natural frequencies and harmonic responses of cylindrical shells partially and completely filled with fluid under various boundary conditions. The vibration frequencies for different filling ratios of cylindrical shells are obtained and compared with existing experimental and theoretical results which indicate that the fluid filling can reduce significantly the natural frequencies of studiedcylindrical shells. Detailed parametric analysis is carried out to show the effects of some geometrical and material parameters on the natural frequencies of orthotropic cylindrical shells. The advantages of this current solution consist in fast convergence, low computational cost and high precision validating for all frequency ranges

    Green synthesis and crystal structure of 3-(benzo-thia-zol-2-yl)thio-phene.

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    The title compound, C11H7NS2, was prepared in high yield (87%) using a solvent-free microwave-assisted synthesis. The structure shows whole-mol-ecule disorder with occupancies for two orientations (A and B) of 0.4884 (10) and 0.5116 (10), respectively. The thio-phene and benzo-thia-zole rings are almost planar and make dihedral angles of 10.02 (18) and 12.54 (19)° for orientations A and B, respectively. Slipped π-π stacking between the aromatic rings, together with C-H⋯π, C-H⋯S and C-H⋯N inter-actions, result in a herringbone motif in the crystal packing

    EFFECT OF FISH SCALE COLLAGEN ON SOME CHARACTERISTICS AND DRUG RELEASE OF CARRAGEENAN/COLLAGEN/ALLOPURINOL FILM

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    ABSTRACT - QMFS2019Collagen from fish is attracting a lot of attention thanks to its high absorbance ability, biocompatibility as well as non-religious obstruction and cheap sources. It could be applied in many fields, for example: food, cosmetic, or biomedicine. Using of collagen also helps to reduce the environment pollution from fish scale waste in fish processing. In this study, collagen extracted from Vietnamese fresh-water tilapia fish scales was used in combination with carrageenan for the improvement of drug release control. The influence of fish scale collagen content on morphology, thermal behavior and drug release from carrageenan/collagen/allopurinol composite film was evaluated by methods such as field emission scanning electron microscopy (FESEM), differential scanning calorimetric (DSC) and ultraviolet-visible spectroscopy (UV-Vis). From the DSC data, FESEM analysis and drug release of carrageenan/collagen/allopurinol composite films, the most suitable collagen in composite film is 5 wt.%

    Crystal structure of (<i>E</i>)<i>-N</i>'-[1-(4-amino-phen-yl)ethyl-idene]-2-hy-droxy-5-iodo-benzohydrazide methanol monosolvate.

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    In the title compound, C15H14IN3O2·CH3OH, two aromatic rings are linked by an N-substituted hydrazide function. The dihedral angle between the aromatic rings is 10.53 (8)°. The stereochemistry about the imine function is E. The methanol mol-ecule forms an O-H⋯O hydrogen bond to the hydrazide O atom. In the crystal, chains of mol-ecules running along the c-axis direction are formed by O-H⋯O hydrogen bonds. Adjacent chains are linked through N-H⋯O hydrogen bonds and π-π stacking inter-actions. The inter-molecular inter-actions in the crystal packing were investigated using Hirshfeld surface analysis, which indicated that the most significant contacts are H⋯H (38.2%), followed by C⋯H/H⋯C (20.6%), O⋯H/H⋯O (11.1%) and I⋯H/H⋯I (9.7%)

    Crystal structure of two <i>N</i>'-(1-phenyl-benzyl-idene)-2-(thio-phen-3-yl)acetohydrazides.

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    The synthesis, spectroscopic data, crystal and mol-ecular structures of two N'-(1-phenyl-benzyl-idene)-2-(thio-phen-3-yl)acetohydrazides, namely N'-[1-(4-hy-droxy-phen-yl)benzyl-idene]-2-(thio-phen-3-yl)acetohydrazide, C13H10N2O2S, (3a), and N'-[1-(4-meth-oxy-phen-yl)benzyl-idene]-2-(thio-phen-3-yl)acetohydrazide, C14H14N2O2S, (3b), are described. Both compounds differ in the substituent at the para position of the phenyl ring: -OH for (3a) and -OCH3 for (3b). In (3a), the thio-phene ring is disordered over two orientations with occupancies of 0.762 (3) and 0.238 (3). The configuration about the C=N bond is E. The thio-phene and phenyl rings are inclined by 84.0 (3) and 87.0 (9)° for the major- and minor-occupancy disorder components in (3a), and by 85.89 (12)° in (3b). Although these dihedral angles are similar, the conformation of the linker between the two rings is different [the C-C-C-N torsion angle is -ac for (3a) and -sc for (3b), while the C6-C7-N9-N10 torsion angle is +ap for (3a) and -sp for (3b)]. A common feature in the crystal packing of (3a) and (3b) is the presence of N-H⋯O hydrogen bonds, resulting in the formation of chains of mol-ecules running along the b-axis direction in the case of (3a), or inversion dimers for (3b). The most prominent contributions to the surface contacts are those in which H atoms are involved, as confirmed by an analysis of the Hirshfeld surface

    Development of a solar/LED lighting system for a plant tissue culture room

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    As the green energy, sunlight provides a friendly-environment and reduces electricity used for lighting. Our target is to enhance the use of natural energy and minimize the consumption of electricity for improving indoor environments. For this reason, a hybrid lighting system, combining sunlight with LEDs for plant tissue culture, are presented. The optical fiber daylighting system consists of three main parts: concentration, collimation beam, and transportation. The concentration part is formed by Fresnel lenses to collect and focus the sunlight into a small area by a non-imaging optical effect. The collimation part consists of optical filters and collimator lenses; the optical filters are used to reflect the ultraviolet (UV) and near infrared (NIR) regions, therefore, only the visible range of the solar light can be transmitted. The transportation part is a large-core optical fiber bundle. To increase the coupling efficiency, the collimator lens is used to expand and to collimate the focused light beam. The collimated light beam is then transported by the optical fiber bundle into a plant tissue culture room. In order to keep the plant tissue culture room at a constant illumination, a lighting control system based on LEDs is used to compensate variations of the natural light. In this paper, a prototype of optical fiber daylighting system and our proposed application will be presented.Ánh sáng mặt trời, một nguồn năng lượng xanh, được sử dụng cho chiếu sáng nhằm mang lại nguồn ánh sáng thân thiện với môi trường và giảm điện năng. Mục tiêu của chúng tôi là tăng cường sử dụng năng lượng tự nhiên và linh kiện tiêu thụ điện thấp để cải thiện môi trường ánh sáng trong nhà và giảm tiêu thụ điện cho chiếu sáng. Vì lý do này, một hệ thống chiếu sáng kết hợp ánh sáng mặt trời với đèn LED để nuôi cấy mô thực vật sẽ được trình bày. Hệ thống chiếu sáng ban ngày bằng sợi quang bao gồm ba phần chính:Bộ phận thu nhận và hội tụ ánh sáng, bộ phận chuẩn trực chùm sáng và bộ phận vận chuyển ánh sáng mặt trời tới nơi cần chiếu sáng. Phần tập trung được hình thành bởi một thấu kính Fresnel để thu thập và hội tụ ánh sáng mặt trời vào một vùng nhỏ bằng hiệu ứng quang học không tạo ảnh. Bộ phận chuẩn trực chumg sáng bao gồm bộ lọc quang học và thấu kính chuẩn trực. Bộ phận vận chuyển là các bó sợi quang lõi lớn. Bộ lọc quang học được sử dụng để phản xạ vùng cực tím (UV) và vùng hồng ngoại gần (NIR), chỉ cho phần ánh sáng nhìn thấy truyền qua. Để tăng hiệu quả ghép nối, thấu kính chuẩn trực được sử dụng để mở rộng và chuẩn trực chùm ánh sáng hội tụ. Chùm sáng chuẩn trực sau đó được vận chuyển bởi bó sợi quang vào phòng nuôi cấy mô thực vật. Để giữ cho phòng nuôi cấy mô thực vật được chiếu sáng liên tục, một hệ thống điều khiển ánh sáng dựa trên đèn LED để bù lại sự biến đổi của ánh sáng tự nhiên. Trong bài báo này, một nguyên mẫu của hệ thống chiếu sáng ban ngày bằng sợi quang và ứng dụng đề xuất của hệ thống sẽ được trình bày

    Crystal structure of 4-amino-3-(thio-phen-3-ylmeth-yl)-1<i>H</i>-1,2,4-triazole-5(4<i>H</i>)-thione.

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    In the title compound, C7H8N4S2, the thio-phene ring shows rotational disorder over two orientations in a 0.6957 (15):0.3043 (15) ratio. The plane of the 1,2,4-triazole ring makes a dihedral angle of 75.02 (17)° with the major-disorder component of the thiophene ring. In the crystal, two types of inversion dimers, described by the graph-set motifs R22(8) and R22(10), are formed by N-H⋯S inter-actions. Chains of mol-ecules running in the [101] direction are linked by weaker N-H⋯N inter-actions. The thio-phene ring is involved in π-π and C-H⋯π inter-actions
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