Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis

One of the main consumers of microcrystalline cellulose (MCC) is the pharmaceutical industry, where MCC is used as a binder and filler in direct compression of tablets. MCC is produced by acidic hydrolysis of cellulose, which usually results in a decrease in whiteness. This is due to the destruction of sugars formed during hydrolysis and the subsequent formation of colored products. The composition and properties of these products depend on the method of hydrolysis, acid concentration, temperature, and process duration. One of the most promising methods for producing MCC is gas-phase hydrolysis of cellulose with hydrogen chloride gas-air mixtures. The method has a high rate of hydrolysis, low reagent and energy consumption. The requirements of the pharmaceutical industry determine the need to produce MCC with high whiteness. The research purpose is to select bleaching modes for MCC using sodium hypochlorite and hydrogen peroxide as bleaching agents. MCC produced by gas-phase hydrolysis of bleached wood pulp was used during the study. The whiteness and intensity of the yellow tint of MCC in the bleaching process were determined by digital colorimetry on a flatbed scanner. The paper shows that sodium hypochlorite and hydrogen peroxide allow achieving the whiteness not less than 90 % and the intensity of the yellow tint not more than 3 standard units. High-quality bleaching can be carried out even for MCC samples with an initial whiteness of about 40 %. The most effective bleaching agent is sodium hypochlorite when the pH of the bleaching solution is 2–3. Hydrogen peroxide also provides high whiteness of MCC at pH of 10–11. However, the consumption of active oxygen (AO) for bleaching is more than three times higher in comparison with the consumption of active chlorine (ACh). It was found that the dyes of MCC produced by gas-phase hydrolysis consist of two chromophore groups that decolorize at different rates. The easily oxidized group of components makes up about 90 % of the total amount of dyes, and the resistant to oxidation components make up about 10 % and determine the intensity of the yellow tint of MCC. The modes of bleaching MCC with sodium hypochlorite and hydrogen peroxide to product samples with whiteness comparable to that of imported samples were determined. For citation: Sizov A.I., Pimenov S.D., Stroiteleva A.D., Stroiteleva K.D. Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 173–183. DOI: 10.37482/0536-1036-2021-6-173-183

Headache, Uveitis, and Leptomeningeal Enhancement

A 35-year-old man sought care for a severe, acute-onset, pounding, bifrontal headache, photopsias, and nausea for 1 day. Initially, bilateral red eyes developed, and within 24 hours he had central blurred vision problems in the left eye. He reported that objects had a yellow tint with the left eye and looked “wavy” supranasally. An emergent evaluation documented bilateral red eyes, and an initial diagnosis of bilateral panuveitis was given. By 48 hours after symptom onset, he started vomiting. He also was feeling feverish and off-balance. He reported no tinnitus or hearing loss, any change in color of his eyelashes or eyebrows, alopecia, poliosis, or cognitive difficulties. An initial work-up for infectious processes was negative. Given the patient’s ethnic background, including Chinese, Japanese, and Filipino origin, and typical findings of uveomeningitis, he was diagnosed with probable Vogt-Koyanagi-Harada syndrome. There is no specific diagnostic test for this entity, and the diagnosis remains reliant on a combined interpretation of clinical and ancillary testing. The patient was kept on oral prednisone daily, and azathioprine was initiated, as well as prophylaxis against Pneumocystis carinii pneumonia and gastrointestinal tract hemorrhage. During the tapering phase of prednisone, liver function test abnormalities were found, so azathioprine was discontinued. At 1-year follow-up, he had some mild skin flaking and weight gain from the corticosteroid therapy but no other symptoms, despite having discontinued azathioprine for 3 months. He continued to taper off prednisone. He had development of bilateral hip pain; imaging showed bilateral aseptic hip necrosis. A decision was made to initiate tumor necrosis factor (TNF)-α‎ inhibitors. He lost all the weight gained and recovered from the aseptic necrosis of the hip to be able to continue running. The final diagnosis was recurrent Vogt-Koyanagi-Harada syndrome. Vogt-Koyanagi-Harada syndrome is an idiopathic inflammatory disease with panuveitis and neurologic involvement in the form of aseptic meningitis and/or hearing loss. Although the full spectrum of the disorder may involve many skin changes and additional findings, most patients have incomplete disease because they are urgently treated with corticosteroids and the disorder is steroid responsive.

Elaboration, characterization and color stability of an isotonic beverage based on whey permeate with carotenoid powder from pequi

The aim of our research was to elaborate, characterize and evaluate the stability under light/darkness and different temperatures (4 and 25 ºC) of the color of an isotonic beverage based on whey permeate with carotenoid extract powder from pequi, and verify its microbiological safety and sensory acceptance. The 3% (w/v) concentration of powdered carotenoid from pequi was chosen because it has osmolality (314.89 mOsmol/L) in the range of hydroelectrolytic beverages and light-yellow tint. The beverage was evaluated for minerals Na (662 mg/L), K (1363.73 mg/L), total carotenoids (75.9 mg/L) and antioxidant capacity by the radicals ABTS (10.79 μmol equivalent Trolox/100 mL) and DPPH (73.38 μmol equivalent Trolox/100 mL), had good sensory acceptance by athletes and remained within microbiological criteria during stability study. The color coordinate L* has undergone less change and C*, greater change. The condition darkness at 4 ºC showed less change in yellow tint, for more than 30 days (t1/2=121.6 day). Due to its characteristics, the beverage has potential benefits for consumption by athletes, because besides being isotonic, it has bioactive properties of pequi carotenoids and natural constituents of whey permeate. The use of permeate, often discarded as effluent, has benefits for the environment.

Virtual Cleaning of Works of Art Using Deep Convolutional Neural Networks

Virtual cleaning of art is a key process that conservators apply to see the likely appearance of the work of art they have aimed to clean, before the process of cleaning. It is also of public interest, allowing people to see their favorite work of art without the yellow tint of the varnish which has covered the work. There have been many different approaches to virtually clean artwork, all of which need to physically clean the work in at least a few spots, an impediment in some cases. Another issue regarding the methods devised until now is that some of them need samples of pure white or black paint on the painting which might be, again, an obstacle as there are certainly works without any pure black and white paint. To overcome these shortcomings, a Convolutional Neural Network is trained on representative RGB images; the images are first artificially yellowed using a physics based model and the network is trained to go from the yellowed images to the original colored images. The results show improvement over a proposed method using a physical model to remove the impacts of age. The CNN is then applied to images of the Mona Lisa and The Virgin and Child with Saint Anne, both painted by Leonardo da Vinci, and works for which we have images from both before and after physical cleaning. Results show both a qualitative and quantitative improvement in the color quality of the resulting image. The novelty of the work proposed herein lies in two premises. First is the accuracy of the method, which is demonstrated through comparing the method with the only physical approach derived until now. Second is the generalizability of the method which is shown through blindly applying the method to two famous works of art for which no information but an RGB image of the uncleaned artwork is known.

Native tungsten from the Bol'shaya Pol'ya river valley and Mt Neroyka, Russia

Native tungsten (IMA2011-004), W, is officially described as a new mineral from gold placers in the Bol'shaya Pol'ya river valley, Prepolar Urals, Russia, associated with yttriaite-(Y) and from quartz veins in the Mt Neroyka rock-crystal field, Ust–Puiva, Tyumenskaya Oblast', Russia. Tungsten forms polycrystalline grains and masses, and rarely cubo-octahedra. It is silver white to steel grey in colour, with metallic lustre and grey streak. The calculated density is 19.226 g/cm3. The Vickers hardness (VHN25) is 571.45 kg/mm2. In plane polarised light, tungsten is white with a pale-yellow tint and optically isotropic. Electron microprobe analyses of Bol'shaya Pol'ya river valley material provided W 99.27, Mo 0.06, Mn 0.04, Fe 0.01, total 99.38 wt.%. The five strongest powder X-ray diffraction lines are [dobs Å(I)(hkl)]: 2.2422(100)(110), 1.5835(25)(200), 1.2929(48)(211), 1.0010(23)(310) and 0.8457(24)(321). Tungsten is cubic, Im $\bar{3}$ m, a = 3.1648(4) Å, V = 31.69(4) Å3 and Z = 2. Some additional occurrences of native tungsten and technogenic tungsten found in Nature are also described.

Development of the active clatrate of 3- (2-phenylethyl) -2-thioxo-1,3 thiazolidin-4-one with β-cyclodextrin and study of its bioavailability.

At present, the class of rhodanine com-pounds containing 4-oxo-2-thioxo-1,3-thiazolidine residues is very promising in the development of medical and veterinary drugs. The purpose of the work is to develop a chemical compound 3- (2-phenylethyl) -2-thioxo-1,3 thiazolidin-4-one (XC-3-2-FE-2-TO-1,3T-4-OH) based on clathrate with β- cyclodextrin (CD) - a supramolecular com-pound (CMC) with improved biopharmaceu-tical properties (solubility and bioavailabil-ity). The lattice clathrates KhS-3-2-FE-2-TO-1,3T-4-OHa with CD were synthesized at the ratios of their masses 1: 5 and 1:10. CMC is a crystalline powder of white with a yellow tint with a particle size of less than 100 nm. For the first time, a method was developed for the quantitative determination of CHS-3-2-FE-2-TO-1,3T-4-OHa in the blood plasma of dogs by high performance liquid chromatography (HPLC). In the range of 0.2-4.0 μg / ml, the calibration curve is linear for ChS-3-2-FE-2-TO-1,3T-4-OH, while the regression equation is described by y = 3.977 + 30.343 × X, s the coefficient of accuracy of the approximation equal to R2 = 0.999. The lower limit of quantitative detec-tion is 10 ng / ml. The average maximum concentrations (Cmax) of ChC-3-2-FE-2-TO-1,3T-4-OHa in the blood plasma of dogs with it, as well as in the form of a clathrate single oral administration, respectively, were 0.66 ± 0, 25 and 3.03 ± 0.82 μg / ml (P≤0.05). The average values of the parame-ter AUC (0 → t) with the introduction of ChS-3-2-FE-2-TO-1,3T-4-On and its clath-rate with CD, respectively, were 4.07 ± 2.15 μg × h / ml and 24.58 ± 5.66 μg × h / ml (P≤0.05). According to a pharmacokinetic study, the best bioavailability (DB) is pos-sessed by the C-3-2-FE-2-TO-1,3T-4-OHa clathrate with CD in a ratio of 1: 5, the ob-tained DB value is 6.4 times higher than the same the value of the original compound. It was concluded that, in terms of biopharma-ceutical properties, the most promising agent for medical and veterinary use is the XC-3-2-FE-2-TO-1,3T-4-OHa clathrate with CD with a mass ratio of 1: 5 and an average par-ticle size of 40.5 nm

The Colour of Tropical Woods Influenced by Brown Rot

Interesting aesthetic properties of tropical woods, like surface texture and colour, are rarely impaired due to weathering, rotting and other degradation processes. This study analyses the colour of 21 tropical woods before and after six weeks of intentional attack by the brown-rot fungus Coniophora puteana. The CIEL*a*b* colour system was applied for measuring the lightness, redness and yellowness, and from these parameters the hue tone angle and colour saturation were calculated. Lighter tropical woods tended to appear a less red and a more yellow, and had a greater hue tone angle. However, for the original woods was not found dependence between the lightness and colour saturation. Tropical woods at attack by C. puteana lost a weight from 0.08% to 6.48%. The lightest and moderately light species—like okoumé, iroko, ovengol and sapelli—significantly darkened, while the darkest species—wengé and ipé—significantly lightened. The majority of tropical woods obtained a brighter shade of yellow, typically wengé, okoumé and blue gum, while some of them also a brighter shade of green, typically sapelli, padouk and macaranduba. C. puteana specifically affected the hue tone angle and colour saturation of tested tropical woods, but without an apparent changing the tendency of these colour parameters to lightness. The total colour difference of tested tropical woods significantly increased in connection with changes of their lightness (ΔE*ab = 5.92 − 0.50·ΔL*; R2 = 0.37), but it was not influenced by the red and yellow tint changes, and weight losses.

INVESTIGATION OF THE INFLUENCE OF CRYOPOWDERS “BROCCOLI” AND “LAMINARIA” ON QUALITY PARAMETERS OF CHEESE MASSES OF DIFFERENT FAT

Crafty combination of cryopowders as bio-supplements to the “milk” base has great prospects in both bio-technological and social aspect. Main criteria at developing recipes of cheese masses were a search for optimal ratios of components for getting proper normative taste characteristics. In this connection, there is offered to study the influence of cryopowders “Broccoli” and “Laminaria” on quality parameters of cheese masses of the new generation, namely ones of the treating-prophylactic destination. The analysis of organoleptic characteristics of salty cheese masses with the cryopowders “Laminaria” and “Broccoli” demonstrates that they have undergone no essential changes and correspond to normative requirements. Thus, the color of salt masses with the cryopowder “Laminaria” was light-grey with a green tint: at using the cryopowder “Broccoli” – grey with a yellow tint. The smell of cheese masses remained fresh, sour-milk. But the expressed smell of the added cryosupplement was felt in samples. The smack of experimental samples at adding the cryopowder “Broccoli” was more expressed. Their consistence was homogenous, delicate, paste-like. The titrated acidity of experimental samples of salty cheese masses with the cryopowder “Laminaria” was 124–130 0Т, mass share of moisture 62–60 % and mass share of dry substance – 40–38 %, and values of energetic value were 164 and 118 kcal/100 g of the product. The titrated acidity of experimental samples of salty cheese masses with the cryopowder “Broccoli” was 126–134 0Т, mass share of moisture 63–66 % and mass share of dry substances – 34–37 %, and values of energetic value were 174 and 128 kcal/100 g of the product. Cheese salty masses with using the cryopowders “Laminaria” and “Broccoli” as phytosupplements are products of the increased biological value, which production doesn’t need the additional specialized equipment, is a potential source as to widening the assortment of products of the treating-prophylactic destination.

Difference Analysis of Different Standard Illuminants on Yellow-Green to Green Jadeite-Jade

Under A, CWF, D55, D65, D75 five different illuminants, color differences of 53 natural oval Jadeite-jade with fine texture are analyzed, which color is yellow-green to dark green. All 5 tested lighting sources were compared based on the uniform color space CIE 1976L*a*b*. Jadeite-jade’s lightness L* is increasing when color temperatures of five different standard illuminants increase, and it can reach the very top of 45.72 under D75, so it appears brighter and lighter than any other illuminants and it influences the appraisal of the samples’ color. The spectrum power distribution of D75, D65 and D55 reveal the strong radiant energy in the range from 500 to 570nm, so consequently the color coordinates a*, b* and chroma C* is higher than the other two illuminants. But samples’ lightness and chroma under D55 are weaker compared to D65 and the color under D55 is dark. Meanwhile, D65 stands for the average daylight and color under D65 close to the true color of samples. Because of weakest radiant energy in the range from 500 to 540nm (green area) and strongest radiant energy in the range from 540 to 570nm (orange area) in CWF’s spectrum power distribution, the absolute value of a*=14.01 is lowest and b*=12.93 is highest under CWF, so samples’ color under CWF is green with a yellow tint. The maximum hue angle h0 is 150.42 under A, and the absolute value of a* is higher than that under CWF, so it shows stronger green tone than CWF. It is concluded that D65 is preferred to be ideal illuminants for the evaluation of jadeite-jade color green especially compared with other 4 illuminants.