Geochemical, Mineralogical and Isotopic Fracturing during the Progressive Evaporation of Chott Djerid Brine (Southern Tunisia)

Djerid Chott, in southwestern Tunisia, is one of the biggest salt lakes in the world. This work follows the specific precipitation of evaporites through progressive evaporation of Chott Djerid brines using geochemical, isotopic and mineralogical approaches, to explain the intricacy of the working of saline frameworks controlled basically by climatic driving and the underlying geochemical structure acquired from the geographical system. Toward the finish of every evaporation step, solid and liquid samples went through analyses. Djerid brine is remarkably saline (427.7 g/l) and it is supersaturated contrasted with halite. The outcomes indicated that the Chott Djerid brines shaped fundamentally Cl--Na+-SO4- type geochemistry. Added to halite and gypsum as significant minerals, other minor minerals including carnallite, hexahydrite and sylvite were recognized in various phases of progressive evaporation of Djerid brine. Regardless of their low costs, significant minerals are of geo-economic interest because of their high amounts of production. Then, minor valuable minerals secure their geo-economic interest from their excessive costs. In this work, we find the window of precipitation of these valuable minerals' at the evaporation paces of 80% and 100%.

ANALISIS KADAR POLIFENOL DAN AKTIVITAS ANTIOKSIDAN YANG TERDAPAT PADA EKSTRAK BUAH : STUDI KEPUSTAKAAN

ABSTRACTPolyphenols are one of the largest categories of phytochemicals and are the most widely distributed among various types of plants and fruits. Polyphenols can also inhibit, prevent, and reduce oxidation by free radicals, which are good for health. Analysis of polyphenol content starts from the sample preparation process which includes the extraction of solid and liquid samples. The types of solvents commonly used for extraction are ethanol, methanol, and acetone. Furthermore, the analysis of polyphenol levels uses the Folin-Ciocalteau analysis method. The results of the review show that ripe bisbul fruit extract (Diospyros blancoi A. DC.) which was extracted using ethanol as a solvent had the highest polyphenol content and yield of several fruit extracts reported in this review. Meanwhile, the extract of green grapes (Vitis vinifera Linn. Var. Chinsiang) which was extracted using ethanol as a solvent had the lowest levels and yields of polyphenols. The highest antioxidant activity was shown by samples of red dragon fruit extract (Hylocereus polyrhizus (f.a.c weber) britton & rose). Meanwhile, the lowest antioxidant activity was shown by samples of Watermelon (Citrullus lanatus) fruit extract.Keywords: Pholyphenol, Extracts, Solvents, Folin CiocalteauABSTRAKPolifenol adalah salah satu kategori terbesar dari fitokimia yang paling banyak penyebarannya diantara berbagai jenis tanaman dan buah-buahan. Polifenol juga dapat menghambat, mencegah, mengurangi oksidasi oleh radikal bebas sehingga baik untuk kesehatan. Analisis kadar polifenol dimulai dari proses preparasi sampel yang meliputi ekstrasi sampel padat dan ekstraksi sampel cair. Jenis pelarut yang umum digunakan saat pengekstrakan yaitu etanol, metanol, dan aseton. Selanjutnya analisis kadar polifenol menggunakan metode analisis folin ciocalteau. Hasil review menunjukkan Ekstrak buah bisbul matang (Diospyros blancoi A. DC.) yang diekstrak menggunakan pelarut etanol memiliki kadar dan rendemen polifenol yang tertinggi dari beberapa ekstrak buah yang dilaporkan dalam review ini. Sedangkan ekstrak buah anggur hijau (Vitis vinifera Linn. Var. Chinsiang) yang diekstrak menggunakan pelarut etanol memiliki kadar dan rendemen polifenol yang terendah. Aktivitas antioksidan yang tertinggi ditunjukkan oleh sampel ekstrak buah naga Merah (Hylocereus polyrhizus (f.a.c weber) britton & rose) dibandingkan sampel lain dalam review ini. Sedangkan aktivitas antioksidan yang terendah ditunjukkan oleh sampel ekstrak buah Semangka (Citrullus lanatus) dibandingkan sampel lain dalam review ini.Kata kunci: Polifenol, ekstraksi, pelarut, folin ciocalteau

Preservation Method of Rumen Fluid Collected From Harvested Cattle Alters in vitro Digestibility of Reference Feedstuffs

The objective of our experiment was to evaluate preservation and revitalization strategies for rumen inoculum anticipating research and veterinary applications. Rumen fluid samples were collected from 12 harvested cattle. Liquid samples were divided into five 500-mL aliquots which were randomly allocated to one of five treatments in a 2 × 2 + 1 augmented factorial design. Factors included preservation method [freezing (FZN) or lyophilization (LYO)] and preservative (glycerol; + or –). A fresh control (CON) was maintained from each sample. Feedstuffs used in this experiment were alfalfa hay, Coastal bermudagrass hay, cracked maize, rice bran, and soybean meal. Reference feedstuffs were subjected to batch culture in vitro true digestibility (IVTD) and in vitro NDF digestibility (IVNDFD) assays using inoculum from each of the five treatments. There was an effect (P < 0.05) of preservation method, preservative, and their interaction for both IVTD and IVNDFD of each of the five references feedstuffs. Freezing or lyophilization of rumen inoculum reduced (P < 0.05) IVTD and IVNDFD of reference feeds relative to the CON. Despite lower degradation of feeds when frozen or lyophilized rumen fluid was used rather than fresh, differences between them in IVTD and IVNDFD suggest that, in the absence of fresh inoculum, preserved rumen fluid may be a viable option for veterinary applications, such as transfaunation, but likely will not be viable for research applications.

Nanostructured Plasma Polymerized Fluorocarbon Films for Drop Coating Deposition Raman Spectroscopy (DCDRS) of Liposomes

Raman spectroscopy is one of the most used biodetection techniques. However, its usability is hampered in the case of low concentrated substances because of the weak intensity of the Raman signal. To overcome this limitation, the use of drop coating deposition Raman spectroscopy (DCDRS), in which the liquid samples are allowed to dry into well-defined patterns where the non-volatile solutes are highly concentrated, is appropriate. This significantly improves the Raman sensitivity when compared to the conventional Raman signal from solution/suspension. As DCDRS performance strongly depends on the wetting properties of substrates, we demonstrate here that the smooth hydrophobic plasma polymerized fluorocarbon films prepared by magnetron sputtering (contact angle 108°) are well-suited for the DCDRS detection of liposomes. Furthermore, it was proved that even better improvement of the Raman signal might be achieved if the plasma polymer surfaces are roughened. In this case, 100% higher intensities of Raman signal are observed in comparison with smooth fluorocarbon films. As it is shown, this effect, which has no influence on the profile of Raman spectra, is connected with the increased hydrophobicity of nanostructured fluorocarbon films. This results in the formation of dried liposomal deposits with smaller diameters and higher preconcentration of liposomes.

Three dimensional visualization of simulations of liquids and solids

Visualization in three dimensions is invaluable for understanding the nature of condensed and fluid systems, but it is not always easy. In nature it is hard to view sample interiors, but on computers it is possible. We describe and contrast two opposite approaches - “smoke” visualization for viewing interiors of liquid samples and interactive WebGL for solids and molecules. Both are extensions of earlier Technion Computational Physics group projects and complement and are interoperable with the recent SimPhoNy Fp7 project. They require only desktop hardware and software accessible to students. Examples and standalone instructions for both are presented, starting with sample creation and concluding with image galleries.

Oxygen K-edge X-ray absorption spectra of liquids with minimization of window contamination

Oxygen K-edge X-ray absorption spectroscopy is used routinely to study a range of solid materials. However, liquid samples are studied less frequently at the oxygen K-edge due to the combined challenges of high-vacuum conditions and oxygen contamination of window materials. A modular sample holder design with a twist-seal sample containment system that provides a simple method to encapsulate liquid samples under high-vacuum conditions is presented. This work shows that pure silicon nitride windows have lower oxygen contamination than both diamond- and silicon-rich nitride windows, that the levels of oxygen contamination are related to the age of the windows, and provides a protocol for minimizing the background oxygen contamination. Acid-washed 100 nm-thick silicon nitride windows were found to give good quality oxygen K-edge data on dilute liquid samples.

Cross-Contamination Risk of Dental Tray Adhesives: An In Vitro Study

Background: The aim of this study was to investigate the risk of cross-contamination in dental tray adhesives with reusable brush systems. Methods: Four dental tray adhesives with different disinfectant components were examined for risk as a potential transmission medium for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus oralis, and Candida albicans. Bacterial and fungal strains were mixed with artificial saliva. The contaminated saliva was intentionally added to tray adhesive liquid samples. At baseline and up to 60 min, 100 microliters of each sample were collected and cultivated aerobically on Columbia and Sabouraud agar for 24 or 48 h, respectively. Results: At baseline, contamination with Staphylococcus aureus and Candida albicans could be identified in three out of four adhesives. In the subsequent samples, low counts of up to 20 colony-forming units per milliliter could be observed for Staphylococcus aureus. All other strains did not form colonies at baseline or subsequently. Adhesives with isopropanol or ethyl acetate as disinfectant additives were most effective in preventing contamination, while adhesives with hydrogen chloride or acetone as a disinfectant additive were the least effective. Conclusion: Within 15 min, the tested adhesives appeared to be sufficiently bactericidal and fungicidal against all microorganisms tested.