Improving Bagasse Pulp Paper Sheet Properties with Microfibrillated Cellulose Isolated from Xylanase-Treated Bagasse

To improve the properties of paper sheets, microfibrillated cellulose (MFC) was isolated from bleached bagasse pulp pretreated with xylanase enzymes and returned to the pulp in varying amounts. The standard hand sheet paper-making method was used. The effect of adding different amounts of MFC on tensile strength (wet and dry), tear resistance, burst strength, opacity, and porosity of paper sheets was studied. Adding MFC to bagasse pulp improved wet and dry tensile strength, but tear resistance and burst strength decreased with increasing amounts of MFC. Also, adding MFC to bagasse pulp did not significantly affect opacity, slightly decreased porosity, and tightened the texture of the paper sheets as observed from scanning electron microscopy images. The strength properties of paper sheets made from bagasse and MFC were compared with those of paper sheets made from bagasse and softwood fibers. Paper sheets containing MFC had higher tensile strength (wet and dry) than those containing softwood fibers, but the later had higher tear resistance and burst strength

Theoretical Study of the [4+2] Cycloaddition Reaction of Trifluoroethylene with Five-membered Chalcogens Heterocyclic Compounds

[4+2] cycloaddition reaction has enormous significant in organic chemistry synthesis reactions and yet remains unexplored for the synthesis of fluorine-containing compounds. A density functional theory study of the stereo- and regioselectivity of the [4+2] cycloaddition reaction of trifluoroethylene with furan, thiophene, and selenophene was carried out in the gas phase. The B3LYP functional is used throughout in combination with 6-31G(d) basis set. The analysis of stationary points and the energetic parameters indicates that the reaction mechanism is concerted and confirms that the exo-adducts are thermodynamically and kinetically more favored than endo-adducts. The calculated branching ratio indicates that the exo-adducts have the higher percent yield than endoadducts and the yield of endo-adducts is increased only slightly on proceeding from furan, through thiophene, and onto selenophene. The analysis of the frontier molecular highest occupied molecular orbital (MO) and lowest unoccupied MO orbitals indicates that the exo-adducts are more stable due to their higher energy gab. The reaction energies were compared to the MP2/6-31G(d) and CCSD(T)/6-31G(d) calculations

Molekularni dokaz infekcija uzrokovanih hemoplazmama u pasa u južnom Iranu i njihovo razlikovanje na osnovi polimorfizma dužine restrikcijskog fragmenta.

Two hemoplasma species are known in dogs: Mycoplasma haemocanis (Mhc) and Candidatus Mycoplasma haematoparvum (CMhp). The aim of the present study was to develop a novel restriction fragment length polymorphism (RFLP)-PCR method based on the 16S rDNA gene, using endonuclease Hind III, for detection and differentiation of canine hemoplasmas. Also, analysis of risk factors, clinical features and hematologic changes of positive cases was performed in dogs living in the Shiraz area of Iran. Blood samples were collected from anemic (packed cell volume (PCV) ≤35; n = 26) and control dogs (PCV >35; n = 27) and were examined for the presence of canine hemoplasmas, using RFLP-PCR and 16S rDNA Sanger sequencing. The presence of Mhc (4 out of 53 cases; 7.5%) and CMhp (3 out of 53 cases; 5.7%) was confirmed by RFLP analysis of the amplified 16S rDNA and sequencing. No association was found between hemoplasma infection and anemia, health status, age, breed, gender, type of housing or the presence of other dogs in this study. Only the platelet number in Mhc infected dogs was statistically higher compared to CMhp positive and hemoplasma negative dogs. The present report documents the occurrence of Mhc and CMhp in southern Iran, and these hemotropic Mycoplasma infections must be expected even in the absence of clinical symptoms or hematologic abnormalities in dogs. For the first time, it has been indicated that RFLP-PCR assay is able to successfully distinguish hemotropic Mycoplasma in dogs.U pasa su poznate dvije vrste hemoplazama: Mycoplasma haemocanis (Mhc) i Candidatus Mycoplasma haematoparvum (CMhp). Cilj je ovog istraživanja bio razviti novu metodu za dokaz i razlikovanje pasjih hemoplazama temeljenu na određivanju polimorfizma dužine restrikcijskog fragmenta (PDRF) gena 16S rDNA uporabom endonukleaze Hind III. Analizirani su i rizični čimbenici, kliničke osobitosti i hematološke promjene u inficiranih pasa na području Shiraza u Iranu. Uzorci krvi bili su prikupljeni od anemičnih (hematokrit ≤35; n = 26) i kontrolnih pasa (hematokrit >35; n = 27) te pretraženi na prisutnost pasjih hemoplazama metodom RFLPPCR i Sangerovom metodom sekvenciranja 16S rDNA. Prisutnost Mhc (4 od 53 slučaja; 7,5%) i CMhp (3 od 53 slučaja; 5,7%) bila je potvrđena analizom polimorfizma restrikcijskog fragmenta 16S rDNA i sekvenciranjem. Nije ustanovljena veza između infekcije hemoplazmama i anemije te zdravstvenog stanja, dobi, pasmine, spola, načina držanja i prisutnosti drugih pasa. Jedino je broj trombocita u pasa inficiranih vrstom Mycoplasma haemocanis bio statistički značajno veći od onih inficiranih Candidatus Mycoplasma haematoparvum i pasa negativnih na hemoplazme. Ovo izvješće potkrepljuje prisutnost Mhc i CMhp u južnom Iranu. Infekcije hemotropnim mikoplazmama mogu se očekivati i u pasa bez kliničkih znakova ili hematoloških poremećaja. Prvi put je pokazano da se metodom RFLP-PCR mogu uspješno razlikovati hemotropne mikoplazme u pasa

Effect of Pretreatment of Bagasse Pulp on Properties of Isolated Nanofibers and Nanopaper Sheets

Nanofibers were isolated from bagasse pulp pretreated with dilute hydrochloric acid, dilute sodium hydroxide, cellulase, or xylanase enzymes using high-shear ultrafine grinding and high-pressure homogenization. The effect of the different pretreatments on chemical composition and structure of isolated nanofibers was studied using chemical analyses, X-ray diffraction, and Fourier transform infrared. The dimensions and properties of the isolated nanofibers were followed at the different processing stages using optical microscopy, transmission electron microscopy, atomic force microscopy, and tensile properties (wet and dry). The diameter of the microfibrils was in the range of 7-30 nm for untreated and pretreated bagasse pulps while larger microfibrillar bands (to 150 nm wide) were observed for untreated bagasse pulp than the pretreated pulps (to 90 nm wide). Nanopaper sheets made from nanofibers isolated from alkali- and xylanase-treated pulps showed better wet and dry tensile strength than those made from the other pulps

Antioxidant, antimicrobial and cytotoxic activities of Corypha taliera Roxb

The methanol extract of Corypha taliera fruits as well as its n-hexane, carbon tetrachloride, dichloromethane and aqueous soluble fractions were subjected to screening for antioxidant, antimicrobial and cytotoxic activities. The methanolic crude extract exhibited the highest antioxidant activity (IC50 19.33 μg/ml as compared to 9.5 μg/ml for the standard agent, BHT). The crude methanol extract and its carbon tetrachloride, dichloromethane and aqueous soluble fractions showed mild to moderate inhibition of microbial growth against some of the tested organisms. All the extractives exhibited strong cytotoxic properties, among which the methanol extract revealed the strongest cytotixicity (LC50 = 0.43 μg/ml).Colegio de Farmacéuticos de la Provincia de Buenos Aire

An improved genetic algorithm based fractional open circuit voltage MPPT for solar PV systems

To extract the maximum power from solar PV, maximum power point tracking (MPPT) controllers are needed to operate the PV arrays at their maximum power point under varying environmental conditions. Fractional Open Circuit Voltage (FOCV) is a simple, cost-effective, and easy to implement MPPT technique. However, it suffers from the discontinuous power supply and low tracking efficiency. To overcome these drawbacks, a new hybrid MPPT technique based on the Genetic Algorithm (GA) and FOCV is proposed. The proposed technique is based on a single decision variable, reducing the complexity and convergence time of the algorithm. MATLAB/Simulink is used to test the robustness of the proposed technique under uniform and non-uniform irradiance conditions. The performance is compared to the Perturb & Observe, Incremental Conductance, and other hybrid MPPT techniques. Furthermore, the efficacy of the proposed technique is also assessed against a commercial PV system\u27s power output over one day. The results demonstrate that the proposed GA-FOCV technique improves the efficiency of the conventional FOCV method by almost 3%, exhibiting an average tracking efficiency of 99.96% and tracking speed of around 0.07 s with minimal steady-state oscillations. Additionally, the proposed technique can also efficiently track the global MPP under partial shading conditions and offers faster tracking speed, higher efficiency, and fewer oscillations than other hybrid MPPT techniques

Antioxidant, antimicrobial and cytotoxic activities of Corypha taliera Roxb

The methanol extract of Corypha taliera fruits as well as its n-hexane, carbon tetrachloride, dichloromethane and aqueous soluble fractions were subjected to screening for antioxidant, antimicrobial and cytotoxic activities. The methanolic crude extract exhibited the highest antioxidant activity (IC50 19.33 μg/ml as compared to 9.5 μg/ml for the standard agent, BHT). The crude methanol extract and its carbon tetrachloride, dichloromethane and aqueous soluble fractions showed mild to moderate inhibition of microbial growth against some of the tested organisms. All the extractives exhibited strong cytotoxic properties, among which the methanol extract revealed the strongest cytotixicity (LC50 = 0.43 μg/ml).Colegio de Farmacéuticos de la Provincia de Buenos Aire

Experimental and numerical investigation of the effect of water cooling on the temperature distribution of photovoltaic modules using copper pipes

In hot climates, PV efficiency drops dramatically if the surface temperature of the panels rises over a specific limit. Consequently, a cooling system is required to preserve PV modules as close to their operating temperature as feasible. For this purpose, the influence of an increase in PV surface temperature on PV performance was studied experimentally and numerically at the Research Institute of Petroleum Industry (RIPI) in July. The current study uses a cooling system consisting of rows of copper pipes connected to the PV backside. The experiments are conducted for four distinct scenarios, each with a different input fluid temperature ranging from 19.5 to 61 °C. The parametric analysis focuses on three influential factors: ambient temperature, solar radiation, and fluid inlet temperatures. In addition, other inputs are configured in accordance with the experimental conditions. The results showed that installing a cooling water system decreased the PV surface temperature from 60.20 °C to 40.24 °C at 9:00 am and from 73.98 °C to 73.33 °C at 1:30 pm. Furthermore, the electrical, thermal, overall, and exergy efficiencies drop as radiation intensity and water inlet temperature increase. In addition, the numerical results are validated with the experimental ones, and it shows high degrees of concordance