Bleaching Method Research Articles

Allomorphic regulation of bamboo cellulose by mild alkaline peroxide for holocellulose nanofibrils production

The exploration of sustainable lignocellulosic nanomaterials with unique properties and applicable functions is receiving growing interest. In this work, holocellulose nanofibrils (HCNFs) were prepared from moso bamboo using mild alkaline peroxide bleaching method (MAPB) followed by mechanical nanofibrillation. MAPB was proved to effectively remove lignin and retain hemicellulose. Meanwhile, partial allomorphic changes from cellulose I to cellulose II were revealed together with varying degrees of crystallinity. Thermogravimetric analysis (TGA) experiment showed an increasing thermal stability trend due to more allomorphic changes into anti-parallel cellulose II. Well-dispersed HCNFs suspensions were successfully prepared by homogenization and HCNFs films with high transparency and flexibility were fabricated. The films reached the maximum tensile strength of 55.8 MPa and tensile strain of 1.55 % along with a calculated toughness of 25 MJ/m3. Moreover, the prepared materials are biocompatible and completely non-toxic, which will theoretically support the application of HCNFs materials in fields of biology, medicine and food industry.

Design and Development of Bamboo and Cotton Blended Fabric using Natural Antibacterial Coating for Infant Clothing

Today natural fiber has become one among the foremost discussed within the research field amongst various scientists and other people within the world rather than using synthetic fibers. This is often thanks to various advantages related to natural fibers like eco-friendly, low cost, availability in abundance and its biodegradability.Bamboo is that the fastest-growing plant on earth. Bamboo fiber is obtained from bamboo pulp, which extracted from the bamboo stem through the method of hydrolysis-alkalization and multiphase bleaching. thanks to the soft silky fabric and environmental benefits of bamboo fiber, bamboo clothing has become popular in some modern luxury fashions.Cotton may be a natural and soft fiber that grows with the seeds of the cotton, round the seed of the cotton plants of the Gossypium within the Malvaceous. Cultivated under controlled environmental conditions, these are very soft and clean to use in various purposes.Aloe vera gel contains powerful antioxidants belongings to an outsized family of substance referred to as polyphenols. These polyphenols, alongside several other components in burn plant, help inhibit the expansion of certain bacteria which will cause infections in humans. In this paperthe bamboo fabric blended with cotton was weaved, and therefore the antibacterial finish of aloe vera gel was applied with the natural dyes of beetroot. The finished fabric isconstructed into a garment.

Microwave‐Assisted Bleaching of Olive Pomace Oil: Optimization of Bleaching Parameters and Comparison with Conventionally Bleached Oil

AbstractIn this research, microwave‐assisted bleaching of olive pomace oil is studied under different conditions. Microwave power, mixing time, and adsorbent dosage are optimized using the response surface central composite design, where the optimum conditions are 102 W, 20.07 min, and 4.15%, respectively. The microwave‐bleached oil is compared with the conventionally bleached oil in terms of color, oxidation parameters, sterol composition, and benzo[a]pyrene content. Microwave‐assisted bleaching of the olive pomace oil is performed by using 17% less adsorbent in an 83% shorter time compared to the conventional method. A bleaching performance comparable to the conventional method is achieved using the microwave‐assisted bleaching technique. Microwave‐assisted bleaching can thus be used as an alternative method for the bleaching of olive pomace oil.Practical applications: The microwave‐assisted bleaching method presents attractive advantages, including a shorter bleaching time and a lower amount of adsorbent used. In this respect, the current research contributes toward the conventional bleaching method in the vegetable oil refinery industry and creates a paradigm for future studies on the bleaching of vegetable oils.

Genoprotective, antimutagenic, and antioxidant effects of methanolic leaf extract of Rhamnus alaternus L. from the Bissa mountains in Algeria

Rhamnus alaternus L. is a Rhamnaceae shrub and a popular traditional medicine in Algeria. The present research objective was to investigate the antioxidant, genotoxic, and antigenotoxic properties of R. alaternus methanolic leaf extract. 
 Antiradical scavenging activity was tested by α, α-diphenyl-β-picrylhydrazyl free radical scavenging and β-carotene bleaching method. DNA damage and repair were measured by the Allium cepa test with sodium azide as a mutagenic agent. Mitotic index and chromosomal aberrations were calculated by microscopy of meristem roots stained with 2% carmine acetic. 
 The methanolic extract of R. alaternus leaves inhibited the free radical DPPH (IC50 = 0.74 ± 0.30 mg/mL) and prevented the oxidation of β-carotene (50.71 ± 4.17%). The root phenotyping showed that sodium azide changed their color and shape, decreased their stiffness, and significantly reduced their length. The roots treated with both R. alaternus leaf extract and sodium azide demonstrated a better root growth. The roots treated with the methanolic extract were much longer than the control roots (P < 0.001). The microscopy images of root meristem treated with the sodium azide mitodepressant agent showed significant chromosomal aberrations, which indicated a disruption of the cell cycle. 
 The R. alaternus leaf extract appeared to have a beneficial effect on cytotoxicity. The antioxidant properties of R. alaternus L. makes this plant an excellent genoportector.

An environment-benign approach of bamboo pulp bleaching using extracellular xylanase of strain Bacillus stratosphericus EB-11 isolated from elephant dung.

The use of microbial enzymes is highly encouraged in paper and pulp industries to reduce the excessive use of hazardous chemicals. During the study, xylanase of BacillusstratosphericusEB-11 was characterized for pulp bleaching applications. The extracellular xylanase was produced under submerged fermentation using bamboo wasteas a natural carbon source. There was fast cell division and enzyme production under optimized fermentation conditions in the bioreactor. The highest activity was 91,200Uafter30h of growth with Km and Vmax of 3.52mg/mL and 391.5μmol/min per mgrespectively. The purified enzyme with molecular mass ~ 60kDa had conferred positive activity on native PAGE. The strong inhibition by ethylenediaminetetraacetate and SDS showed the metallo-xylanase nature of the purified enzyme.The bacterial xylanase reduces the use of hydrogen peroxide by 0.4%. Similarly, biological oxygen demand and chemical oxygen demand were reduced by 42.6 and 35.2%. The xylanase-hydrogen peroxide combined treatment and conventional chlorine dioxide-alkaline (CDE1D1D2) bleaching showed almost similar improvement in physicochemical properties of bamboo pulp. Xylanase-peroxide bleaching reduces the lignin content to 4.95% from 13.32% unbleached pulp. This content after CDE1D1D2treatment was 4.21%. The kappa number decreased from 15.2 to 9.46 with increasing the burst factor (15.51),crystallinity index (60.25%), viscosity (20.1 cp), and brightness (65.4%). The overall finding will encourage the development of new cleaner methods of bleaching in the paper and pulp industry.

Evaluation of modified bleach technique for the detection of acid fast bacilli in lymph node aspirate at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia

BackgroundTuberculous Lymphadenitis (TBLN) is the commonest form of extrapulmonary tuberculosis. Definitive diagnosis of TBLN is difficult due to the low efficacy of the routine diagnostic techniques as compared to culture. ObjectiveTo determine whether prior bleach concentration can improve the detection of acid-fast bacilli when compared with conventional Ziehl-Neelsen (ZN) staining by using culture as the gold standard. MethodsCross-sectional study was conducted from March 01, 2015 to May 30, 2015. The study subjects were clinically suspected TBLN patients. Fine needle aspiration (FNA) was performed. Two different smears were prepared directly from the first needle pass for cytology and ZN staining. The remaining aspirate was used for the modified bleach concentration. The second needle pass aspirate was transferred into a sterile container containing sterile normal saline. The sediment was inoculated on the Lowenstein Jensen (LJ) medium. Measurement parameters for reliability and validity were used to analyze the results. ResultA total of 93 participants were included in the study. Fifty-six out of the 93 (60.2 %) cases were positive for mycobacterium tuberculosis complex on LJ culture. The detection rates of direct ZN staining and modified bleach method were 20.4 % and 44.1 %, respectively. 73.1 % of the cases showed cytomorphological features consistent with TBLN by cytologic examination. The sensitivities of direct ZN staining and modified bleach method and cytomorphology were 32.0 %, 67.8 %, and 92.8 %, respectively. ConclusionImplementation of bleach concentration increases the detection rate of AFB over the direct ZN method. The bleach method can also be easily performed and provide a safe working environment by reducing infections.

Application of the Method of Melanin Bleaching After Immunohistochemical Staining of Melanin-containing Tissues.

The purpose of this research was to investigate the method of melanin bleaching in immunohistochemical staining of melanin-containing tissues. Forty melanin-containing tissue samples were selected, including 30 with malignant melanoma and 10 with blue naevi. The samples were divided into the following 3 groups: the prestaining bleaching group, nonbleaching group, and poststaining bleaching group. Each group was subjected to HMB45 and MelanA immunohistochemical staining. The detection system used was Roche ventana ultraview universal alkaline phosphatase red kit. In the prestaining bleaching group, melanin pigment was mostly removed. However, antigen expression was also affected, which resulted in significantly weaker positive staining and even represented false-negative expression. In the nonbleaching group, positive staining resulted in a red color that could easily be distinguished from the brown granules of melanin pigment. However, some melanin granules covered the tissue, impacting our observation of tissue structure. In the poststaining bleaching group, the results of positive staining were comparable to those in the nonbleaching group. The melanin pigment in these sections was almost completely removed, resulting in clearer staining and easier observation of tissue and cell structure. The method of melanin bleaching after immunohistochemical staining of melanin-containing tissue can almost completely bleach the melanin pigment and do not impact the expression of antigen. In our work, poststaining bleaching allowed for clearer immunohistochemical staining results and more obvious observation of tissue structure. This method also has the advantages of requiring simple reagents, utilizing simple operation procedures, and producing practical staining results, which makes it worthy of promotion!

In vitro and in vivo bioactivities of Ambrosia maritima and Bituminaria bituminosa organic extracts from Algeria.

Two medicinal plants, Ambrosia maritima and Bituminaria bituminosa, growing in Algeria were investigated for their flavonoids content and their biological activities. Different organic extracts were prepared from the aerial parts of each plant using maceration method followed by liquid/liquid type extractions. The anti-antioxidant activity was tested using the β-carotene bleaching method. The anti-inflammatory activity was tested by performing the protein anti-denaturation assay. Acute toxicity and immunostimulatory effect were tested in mice, while the antimicrobial activity was tested according to the minimal inhibition concentration technique. In term of flavonoids content, ethyl acetate extract of B. bituminosa was the highest (193.39 ± 24.1 µg QE/mg). Ethyl acetate extract of A. maritima showed antioxidant activity with IC50 value of 11.72 ± 0.79 µg/mL. The hydroethanolic extract of A. maritima showed the best anti-denaturation effect in a dose-dependent manner with the IC50 value of 131.07 ± 0.027 µg/mL. The studied plants showed no toxicity or mortality in vivo. Both plants showed a significant immunostimulatory effect; while the Butanolic extract of B. bituminosa demonstrated the best antimicrobial activity against Staphylococcus aureus and Candida albicans strains. We recommend A. maritima and B. bituminosa as potent sources of antioxidants and as antimicrobial agents for further assays to better elucidate their actions on the immune system.

Utilization of Peroxide Bleached Sugar Palm (Arenga pinnata) Fibre Waste into Cellulose Nano Crystal

Sugar palm (Arenga pinnata) fibre (SPF) waste is a side product of sugar palm starch production and needs to be processed to avoid environmental pollution. Since the SPF has high cellulose content, it can be beneficial if it is valorized into high-value products such as cellulose nanocrystal (CNC). The CNC production from SPF was initiated by cellulose production by using an environmentally friendly peroxide bleaching as elementary chlorine free bleaching method. The CNC production was conducted via sulfuric acid hydrolysis at a temperature of 40°C, solid/liquid ratio of 1:10, and hydrolysis time of 45, 60, 75, and 90 minutes. The same functional groups were observed in all CNC samples, including the appearance of the ester sulfate group. The decrease in yield and crystallinity index (CrI) as the hydrolysis time was observed. These phenomena were caused by the degradation of the crystalline structure of cellulose and the formation of the ester sulfate group. The measurement of CNC diameter size was carried out by using the scanning electron microscopy (SEM) technique. The CNC diameter was below 100 nm which indicated the nanoparticle formation was observed at CNC produced at hydrolysis times of 75 and 90 minutes. In conclusion, CNC production was successfully produced from peroxide bleached SPF which is more environmentally friendly than the conventional method using chlorite bleached cellulose. Furthermore, it is needed to optimize the production of SPF CNC in further research.

Synthesis, Characterization, and Antioxidant, Antimicrobial and Toxic Properties of Novel Δ2 -1,3,4-thiadiazoline and Δ2 -1,3,4-selenadiazoline Derivatives

Two new series of N-(4-acetyl-5-aryl-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide and N-(4-acetyl-5-aryl-4,5-dihydro1,3,4-selenadiazol-2-yl)acetamide compounds (where aryl = 4-nitrophenyl, 4-hydroxy-3-methoxyphenyl, 3-ethoxy-4- hydroxyphenyl, 2-chloroquinolinyl, and 6-chloro-4-oxo-4H-chromenyl) were synthesized in good yields by heterocyclization of thiosemicarbazones (TSCs) and selenosemicarbazones (SSCs) with acetic anhydride, respectively. The new TSCs and SSCs compounds was prepared by condensation reaction of thiosemicarbazide and Selenosemicarbazide with aromatic aldehydes in acidic medium. The structures of newly synthesized 1,3,4-thiadiazoline (TDZs) and 1,3,4-selenadiazoline (SDZs) derivatives were characterized by the analytical and spectroscopic method such as IR, 1 H NMR, 13C NMR, mass spectra and elemental analysis. The purity of compound and evaluation of Rf value were determined by TLC. The toxicity of new compounds was assayed via the determination of their LD50 value by using Dixon’ s up and down method. The antibacterial activity of 1,3,4-thiadiazoline and 1,3,4-selenadiazoline compounds were tested in vitro against Staphylococcus aureus, Bacillus, Escherichia coli and Pseudomonas aeruginosa. Finally, antioxidant efficiency of all compounds were detected according to β-carotene bleaching method.

Effects of an alternative bleaching method for yerba mate leaves on total phenolic content: evaluation and prediction with soft-computing approaches.

The effects of an alternative bleaching method on the total phenolic content (TPC) and antioxidant activity (AA) of yerba mate extracts were evaluated. Traditional bleaching ('zapeco') was compared with submerging the leaves in water followed by a hot air oven-drying process. Seven different approaches, i.e. linear model (LM), response surface model (RSM), Mamdani, Larsen, adaptive neuro-fuzzy inference system (ANFIS) with the product (Prod) and the minimum (Min) operators, and ANFIS with automatically membership functions (Auto), were employed to compare the TPC of yerba mate extracts based on drying temperature and AA assays. The results showed that if leaves were bleached followed by drying at higher temperatures, we obtained higher AA and TPC values. For submerging bleaching treatment, RSM model delivered the best accuracy measures with a mean absolute error (MAE), average absolute percentage error (MAPE), and mean squared error (MSE) of 0.128, 0.006, and 0.028, respectively. The ANFIS Auto model was the best for traditional bleaching treatment, with MAE, MAPE, and MSE of 0.490, 0.013, and 0.612, respectively. The results suggest a second-order linear relation between drying temperature, AA assays to TPC, and a high level of relation complexity of drying temperature, AA assays, and TPC. The evaluated soft-computing approaches have the excellent ability to estimate TPC from bleached leaves. © 2022 Society of Chemical Industry.

Assessment of lipid preservation by carotenoids extracted from Daucus carota (L.) and Beta vulgaris (L.) roots

Fruits and vegetables are good sources of phytochemicals such as carotenoids capable of preventing diseases and maintaining well-being. This study aims to investigate the antioxidant activity of carotenoids obtained from Daucus carota L. (D. carota) and Beta vulgaris L. (B. vulgaris) roots and to determine their impact on the fat preservation. Carotenoids were extracted using a mixture of an equal volume of methanol, ethyl acetate, and petroleum ether. The antioxidant activity of the roots extracts was determined using DPPH scavenging and β-carotene bleaching methods. The oxidative stability of the butter added to the roots extracts was assessed using the Schall test. Results have shown that carotenoid contents of D. carota and B. vulgaris extracts were about 2.47±0.24 and 1.44±0.09 mg β-carotene equivalent per g of roots extract, respectively. DPPH-scavenging activity revealed IC50 values of 0.58 and 0.89 mg /mL, and a percentage of β-carotene bleaching inhibition of 51.25±4.26% and 56.84% in the presence of 1mg/mL of B. vulgaris and D. carota extract, respectively. The oxidation of the butter fats was significantly reduced (P<0.05) in the presence of the two carotenoid extracts compared to the control. The present study clearly showed the protective effect of D. carota and B. vulgaris against oxidative reactions in general and lipid peroxidation in particular. In addition to its use as a natural colorant, the carotenoids roots extract of these two plants could be used as a potential food preservative.

CYTODIAGNOSIS OF TUBERCULOSIS USING CONVENTIONAL ZIEHL-NEELSON STAINING METHOD AND MODIFIED BLEACH METHOD ON LYMPH NODE ASPIRATES ALONG WITH CLINICAL CORRELATION IN TERTIARY CARE CENTRE.

Tuberculosis (TB) is a common public health problem and second leading cause of communicable disease world wide. Tuberculosis is one of the top ten causes of death and the leading cause from a single infectious agent (above HIV/AIDS). India accounting for almost one fth (21%) of global incidence. Lymphadenopathy accounts for the most common form of Extra-Pulmonary Tuberculosis (EPTB) 3. A prospective study was carried on 100 cases of suspected tubercular lymphadenopathy patients over a period of 18 months at Gajra Raja Medical College and JAH Group of Hospitals, Gwalior from Jan 2020 to Jun 2021. All cases of clinically suspected tubercular lymphadenopathy reporting for Fine Needle Aspiration Cytology (FNAC) examination in Department of Pathology, Gajra Raja Medical College and Jay Arogya Group of Hospitals (J.A.H.), Gwalior, Madhya Pradesh (M.P.) with proper marking for affected lymph nodes and documentation. Aim was to evaluate the efcacy of bleach method with cytological diagnosis and the conventional method. Patients with tubercular lymphadenitis were evaluated. The acid-fast positivity by routine staining was compared with modied bleach method of AFB staining. Among 100 patients, 23(23%) were positive for AFB on conventional ZN method and the smear positivity was increased to 33 (33%) by bleach method. The bleach method is simple and inexpensive. It clearly improves microscopic detection of AFB.

Utility of cartridge based nucleic acid amplification test in diagnosis of tubercular lymph nodes on fine needle aspiration and its comparison with zeihl-neelsen staining and concentration bleach method

Tuberculosis (TB) is one of the oldest disease known to humanity and among the deadliest epidemics and is in the top 10 causes of death worldwide. The incidence of tuberculosis in India has dramatically increased and contributing to it is Human Immunodeficiency Virus (HIV). Various diagnostic methods are available for detection of tubercular bacilli. Only full proof criteria for diagnosis of TB is to demonstrate the bacilli from affected tissue. This study was planned in extra pulmonary tuberculosis cases to evaluate different staining methods for demonstration of mycobacterium on FNAC material. To evaluate efficacy of Cartridge Based Nucleic Acid Amplification Test (CBNAAT) in the initial cytodiagnosis of Tubercular Lymphadenitis 147 clinically suspected cases of extra pulmonary tuberculosis mainly TB lymphadenitis who attended cytology OPD were selected irrespective of age and sex. FNAC was performed. Slides stained for PAP, ZN and concentration bleach. Material remained in hub was sent for CBNAAT. PAP stained slides were observed for various morphological pattern.Six morphological patterns were observed. Positivity for acid fast bacilli by ZN staining, concentration bleach method and CBNAAT were compared. Detection of acid-fast bacilli by CBNATT was found more as compared to ZN and Concentration bleach method.

Phenolic Contents, Organic Acids, and the Antioxidant and Bio Activity of Wild Medicinal Berberis Plants- as Sustainable Sources of Functional Food.

Wild fruits have increasingly been investigated as part of recent searches for food products with a high antioxidant activity. In this study, wild edible berberis Berberis vulgaris collected from three different provinces (Jilin, Heilongjiang, and Liaoning) were investigated for their phenolic contents, organic acid contents, mineral contents, antioxidant activity as well as their antimicrobial potential against a range of common food borne pathogens. In addition, a physiochemical and mineral analysis of the fruits was also performed. The methanol extracts of berberis fruit collected from Jilin province were highly active against all the studied food borne bacterial pathogens, i.e., S. aureus and L. monocytogenes, E. coli, P. fluorescens, V. parahaemolyticus, and A. caviae while the berberis extracts from Heilongjiang and Liaoning showed activity only against Gram-negative bacteria. The phenolic content and antioxidant activity were determined by the HPLC separation method and β-carotene bleaching methods, respectively. Four organic acids such as malic acid, citric acid, tartaric acid, and succinic acid were identified while a variety of phenolic compounds were detected among which catechin, chlorogenic acid, and gallic acid were found to be the predominant phenolic compounds in all three of berberis fruit samples. The berberis fruit from Jilin was found to be superior to the Heilongjiang and Liaoning fruit regarding desired physiochemical analysis; however, there were no significant differences in the mineral contents among the three samples. Overall, the berberis fruit from Jilin was ranked as the best in term of the nutritional, physiochemical, antimicrobial, and antioxidant properties. This study confirms the various useful characteristics and features of berberis at a molecular level that can be used as a sustainable source for their potential nutritional applications for making functional foods in different food industries.

The Potential of Cellulose from the Sugar Palm (Arenga Pinnata) Seed Shell for Removal of Cr(Vi) Ions

Cr (VI) is persistent, bio-accumulative, toxic metal, unable to decompose in the environment, and accumulates in the human body through the food chain. The Cr(VI) ions can remove in aqueous solution by adsorption technique with cellulose extracted. Extract of cellulose were prepare from palm (Arenga pinnata) seed shell using acidified H2SO4 and bleaching methods. The cellulose have contained the hydroxyl (–OH) functional groups in structure, it can be an adsorbent for heavy metal ions. Cellulose was obtained with delignification and bleaching methods to break the bond between lignin and cellulose. The cellulose extracted were characterized by Fourier Transformation Infra-Red (FT-IR) and Scanning Electron Microscopy - Energy Dispersive X-Ray (SEM)-EDX. The adsorption process was conducted using pH, contact time, and concentration of Cr(VI) ions. The results showed that the optimum pH was obtained at pH 3 with an adsorption capacity is 0.88 mg/g. The optimum contact time was obtained at 120 minutes with an adsorption capacity is 0.89 mg/g. The optimum concentration was obtained at a concentration of 200 ppm with an adsorption capacity is 20.34 mg/g

Various Aspects Involved in the Study of Tooth Bleaching Procedure: A Questionnaire-Based Study.

A beautiful smile is an important feature when it comes to a pleasant appearance of the face, and one of the most common situations that drive patients to book a dental appointment is tooth discoloration. Tooth bleaching is the treatment of choice for extrinsic tooth discoloration, as it is a cheap, fast, and minimally invasive procedure. This study aimed to provide comparative information on the perceptions of both patients and dentists regarding different whitening methods and on the factors involved in people’s willingness to recommend and use a bleaching procedure. In addition to this, this study evaluated the degree of satisfaction in relation to the bleaching methods and materials used; it also evaluated the following: negative side effects, economic characteristics and the patients’ perceptions of the aesthetic appearance of their dental arches, especially tooth color. The subjects that participated in the present study were selected based on their background and were then divided into two categories. The first group consisted of 120 patients who had received tooth-bleaching treatments in dental clinics during the study and the second group consisted of 127 dentists. A conventional sampling method was used. The study aimed to define a relationship between multiple aspects of the tooth-bleaching procedure, including the patients’ desires and their general knowledge of this procedure. Tooth color and the way it changes is a very important factor that motivates patients to come to the dentist for whitening procedures. Patients showed the highest levels of satisfaction with the results of in-office bleaching procedures. In the group consisting of dentists, satisfaction levels were higher for the procedure of home bleaching supervised by a dentist. Factors influencing the choice of bleaching materials are appreciated differently by dentists and patients. Furthermore, the rate of patients using OTC (over the counter) products was found to be high. Further research is needed to find more effective and safer alternatives to home tooth-bleaching procedures.

Monomer release from dental restorative materials containing dimethacrylate resin after bleaching.

The aim of this study is to determine the type and amount of monomer released over time after bleaching was applied to dental restorative materials containing dimethacrylate resin. Thirteen different restorative materials containing dimethacrylate resin were used in this study. Twenty samples were prepared from each material and the samples were randomly divided into 4 subgroups, namely, office bleaching, home bleaching, and separate control group for each of the bleaching methods. After bleaching, the samples were stored in 75% ethanol solution for 1, 14, and 28days. Analysis of the samples collected to determine the type and amount of residual monomer released from the materials was performed using a liquid chromatography-tandem mass/mass spectrometer (LC-MS/MS). Data were analyzed using Friedman and Kruskal-Wallis tests. Statistical significance level was taken as p < 0.05. In terms of bleaching groups, mostly no significant difference was found between the groups in each time period in restorative materials (p > 0.05). In terms of time periods, it was determined that the amount of release of all monomers was decreased over time. In terms of restorative materials, the highest monomer release was detected in composite resin groups and the least monomer release was detected in CAD/CAM blocks. Although monomers were released from all materials, bleaching did not affect the amount of released monomer. Amounts of released monomers were generally below toxic limits. Within the limits of this study, bleaching does not significantly affect monomer release in restorative materials containing dimethacrylate resin.

Artemisia absinthium L. Aqueous and Ethyl Acetate Extracts: Antioxidant Effect and Potential Activity In Vitro and In Vivo against Pancreatic α-Amylase and Intestinal α-Glucosidase.

Artemisia absinthium L. is one of the plants which has been used in folk medicine for many diseases over many centuries. This study aims to analyze the chemical composition of the Artemisia absinthium ethyl acetate and its aqueous extracts and to evaluate their effect on the pancreatic α-amylase enzyme and the intestinal α-glucosidase enzyme. In this study, the total contents of phenolic compounds, flavonoids, and condensed tannins in ethyl acetate and the aqueous extracts of Artemisia absinthium leaves were determined by using spectrophotometric techniques, then the antioxidant capacity of these extracts was examined using three methods, namely, the DPPH (2, 2-diphenyl-1picrylhydrazyl) free radical scavenging method, the iron reduction method FRAP, and the β-carotene bleaching method. The determination of the chemical composition of the extracts was carried out using high-performance liquid chromatography—the photodiode array detector (HPLC-DAD). These extracts were also evaluated for their ability to inhibit the activity of the pancreatic α-amylase enzyme, as well as the intestinal α-glucosidase enzyme, in vitro and in vivo, thus causing the reduction of blood glucose. The results of this study showed that high polyphenol and flavonoid contents were obtained in ethyl acetate extract with values of 60.34 ± 0.43 mg GAE/g and 25.842 ± 0.241 mg QE/g, respectively, compared to the aqueous extract. The results indicated that the aqueous extract had a higher condensed tannin content (3.070 ± 0.022 mg EC/g) than the ethyl acetate extract (0.987 ± 0.078 mg EC/g). Ethyl acetate extract showed good DPPH radical scavenging and iron reduction FRAP activity, with an IC50 of 0.167 ± 0.004 mg/mL and 0.923 ± 0.0283 mg/mL, respectively. The β-carotene test indicated that the aqueous and ethyl acetate extracts were able to delay the decoloration of β-carotene with an inhibition of 48.7% and 48.3%, respectively, which may mean that the extracts have antioxidant activity. HPLC analysis revealed the presence of naringenin and caffeic acid as major products in AQE and EAE, respectively. Indeed, this study showed that the aqueous and ethyl acetate extracts significantly inhibited the pancreatic α-amylase and intestinal α-glucosidase, in vitro. To confirm this result, the inhibitory effect of these plant extracts on the enzymes has been evaluated in vivo. Oral intake of the aqueous extract significantly attenuated starch- and sucrose-induced hyperglycemia in normal rats, and evidently, in STZ-diabetic rats as well. The ethyl acetate extract had no inhibitory activity against the intestinal α-glucosidase enzyme in vivo. The antioxidant and the enzyme inhibitory effects may be related to the presence of naringenin and caffeic acid or their synergistic effect with the other compounds in the extracts.

Древесина как химическое сырье. История и современность. IV. Делигнификация древесины как путь получения целлюлозы. Часть I

The article is devoted to the history of the development of wood delignification methods in order to obtain cellulose. A brief description of their use in paper production has been given since its inception. The technologies of sodium, sulfate and sulfite delignification of wood are described in detail. The development of methods of bleaching and ennobling of technical pulps, improvement of their hardware design and their influence on the quality of finished products is shown. The dynamics of the pulp industry development in the leading countries of the world, its current state and development prospects are given. This article is the fourth part of the cycle «Wood as a chemical raw material. History and modernity»; the first, second and third parts are published in the journal Forest Bulletin, 2020, vol. 24, No. 1, No. 5 and 2021, vol. 25, No. 3.