Chemical Preparations Research Articles

Effect of Trichloromethane on the Bond Strengths between Acrylic Teeth and Different Heat-cured Denture Bases: A Comparative Study

This study is to evaluate the role of 1:1 v/v 30% trichloromethane and monomer solvent in enhancing the durability of bonding between cross-linked acrylic teeth and different heatcured denture bases with or without mechanical preparations made on ridge lap portion of the artificial teeth. Two high impact denture base resin materials (Trevalon HI, DeTrey, UK, and DPI Tuff, Mumbai) and one nonhigh impact denture base resin material (DPI Quick Set, Mumbai) were selected to form three groups. Each group contains 30 specimens prepared by five different methods. A mixture of 30% trichloromethane and monomer, mixed in the ratio of 1:1 and applied for 1 minute on the ridge lap area of experimental specimens of methods--B, C, D and E (Specimens of method--A being control group, where no alterations were made at the ridge lap portion of acrylic teeth) before curing. Hounsfield universal testing machine is employed to evaluate the comparative bond strengths. No significant difference was seen in bond strengths between specimens of experimental methods in all groups. When each group was assessed separately method B specimens in group 1 (739.2 N), group 2 (758 N) and method D specimens in group 3 (729 N) showed highest mean bond strengths. Control group specimens showed the least bond strength (400-460 N) in all groups with more adhesive failures. Ridge lap portion of the specimens treated with chemical solvent as in method B showed increased bond strength in groups 1 and 2. Hence, this is a preferred method. Evaluation of effect of different chemical and mechanical preparations at the ridge lap areas of acrylic teeth before acrylization helps the clinician and technician to overcome the problem of debonding of teeth from denture bases and in turn provides better quality prosthesis to the patient.

3D techniques and fossil identification: An elephant shrew hemi-mandible from the Malapa site

Conventional methods for extracting fossilised bones from calcified clastic sediments, using air drills or chemical preparations, can damage specimens to the point of rendering them unidentifiable. As an alternative, we tested an in silico approach that extended preparation and identification possibilities beyond those realisable using physical methods, ultimately proving to be crucial in identifying a fragile fossil. Image data from a matrix-encased hemi-mandible of a micromammal that was collected from the Plio-Pleistocene site of Malapa, Cradle of Humankind, South Africa, were acquired using microtomography. From the resultant images, a 3D rendering of the fossil was digitally segmented. Diagnostic morphologies were evaluated on the rendering for comparison with extant comparative specimens, positively identifying the specimen as an elephant shrew (Elephantulus sp.). This specimen is the first positively identified micromammal in the Malapa faunal assemblage. Cutting-edge in silico preparation technology provides a novel tool for identifying fossils without endangering bone integrity, as is commonly risked with physical preparation.

"Persons That Live Remote from London": Apothecaries and the Medical Marketplace in Seventeenth-and Eighteenth-Century Wales

This article uses evidence from Welsh apothecary shops as a means to access the mechanisms of the "medical marketplace" in seventeenth- and eighteenth-century Wales. As a country physically remote from large urban medical centers, and with few large towns, Wales has often been overlooked in terms of medical commerce. Nevertheless, evidence suggests that Welsh apothecaries participated in broad and sophisticated networks of trade with London suppliers. Moreover, their shops contained a wide range of medicines from herbal simples to exotic ingredients and chemical preparations, highlighting the availability of such goods far from large urban centers.

Inside athletes' minds: preliminary results from a pilot study on mental representation of doping and potential implications for anti-doping.

BackgroundDespite the growing body of literature and putative links between the use of ergogenic nutritional supplements, doping and illicit drugs, it remains unclear whether, in athletes' minds, doping aligns with illicit behaviour or with functional use of chemical or natural preparations. To date, no attempt has been made to quantitatively explore athletes' mental representation of doping in relation to illegality and functionality.MethodsA convenience sample of student athletes from a large South-Eastern Australian university responded to an on-line survey. Competitive athletes (n = 46) were grouped based on self-reported use as follows: i) none used (30%), ii) supplement only (22%), iii) illicit only (26%) and iv) both supplements and illicit drug use (22%). Whereas no athlete reported doping, data provided on projected supplement-, doping- and drug use by the four user groups allowed evaluation of doping-related cognition in the context of self-reported supplement- and illicit drug taking behaviour; and comparison between these substances.ResultsA significantly higher prevalence estimation was found for illicit drug use and a trend towards a biased social projection emerged for supplement use. Doping estimates by user groups showed mixed results, suggesting that doping had more in common with the ergogenic nutritional supplement domain than the illicit drug domain.ConclusionsAssessing the behavioural domain to which doping belongs to in athletes' mind would greatly advance doping behaviour research toward prevention and intervention. Further investigation refining the peculiarity of the mental representation of doping with a larger study sample, controlling for knowledge of doping and other factors, is warranted.

Morphoquantitative study of the submucous plexus (of Meissner) of the jejunum-ileum of young and old guinea pigs

To study the aging of submucous plexus of the small intestine (jejunum-ileum) of the guinea pigs from the quantitative, structural and ultrastructural perspective. Chemical preparations of membrane of the jejunum-ileum of old and young animals with the use of light and electronic microscope. The ganglia of young animals presented between 1 and 56 neurons and the old animals presented from 1 to 30 neurons. The mean density of the ganglia by cm(2) in the young jejunum-ileum was of 551±36.89 and in the old one 413±11.86. The density of the neurons was 5011±291.11 neurons/cm(2) average in young animals and 2918±120.70 neurons/cm(2) in the old ones. The size of the neurons varied in both age groups. The collagen fibers in the ganglia of old animals they were condensed. Degenerated mitochondrias in the interior of the cell were frequent in the old animals. In submucous plexus of the jejunum-ileum there is a loss of 38% of the neurons with aging.

Current issues with paracetamol induced toxicity

Paracetamol (acetaminophen; APAP), a commonly-used analgesic and anti-pyretic drug, is usually safe when administered at therapeutic doses in children. However, at overdoses, APAP has the potential for causing fulminant hepatic necrosis and nephrotoxicity in both humans and animals. In pre-school children, many poisonings are due to chemical or pharmaceutical preparations like APAP which is an important example for poisoning with pharmaceutics. Liver has an important role in the metabolism of toxic chemicals, certain drugs and environmental pollutants. Using the cytochrome P450 pathway, APAP is converted to a highly toxic metabolite, namely N–acetyl–p–benzoquinamine (NAPQI). By this way, ...

A MINIREVIEW OF CELLULOSE NANOCRYSTALS AND ITS POTENTIAL INTEGRATION AS CO-PRODUCT IN BIOETHANOL PRODUCTION

Cellulose nanocrystals appeared as important bio-based products and the collected information in term of production, characterization and application suggest that this nanomaterial could be easily extrapolated to bioethanol production. This review describes recent published syntheses using chemical and enzymatic hydrolyses and different preparations such as high pressure homogenization. Their industrial and medical applications, such as controled of delivery carriers, suggest a large projection of this nanomaterial. The most important aspect in this collected data is the potential to decrease significantly the final cost of the enzymes or the hydrolysis pre-treatment of lignocellulosic materials of all bioethanol processes in such a way that it could be economically feasible from materials such as bagasse, straw or wood resources.

The effect of mechanical roughening and chemical treatment on shear bond strength of urethane dimethacrylate denture base resin

Relining of ill-fitting denture is often required to establish the fit of denture base, hence better retention and stability of the prostheses. However clinical success depends on the ability of reline resin to bond with denture base. The effect of surface preparations of urethane dimethacrylate (UDMA) denture base resin (Eclipse) on the shear bond strength (SBS) to auto-polymerizing polyethyl methacrylate reline material was evaluated. Eclipse specimens were mechanically prepared using two different tungsten carbide burs and submitted to chemical treatments either with dichloromethane (Secure adhesive) or methyl acetate (Eclipse Bonding Agent). Reline resin was then applied to the prepared surface and shear bond strength was tested after 24 h. Data was analyzed using two-way ANOVA and post-hoc Tukey HSD test at p=0.05. The morphological changes of Eclipse surfaces after preparations were also observed under SEM. The results showed that SBS was significantly affected by mechanical roughening, chemical treatment and their interactions. Higher reline SBS values were observed for Eclipse specimens without mechanical roughening compared to those with roughening. Both chemical agents improved reline SBS with the highest bond strength shown when chemically treated using Secure adhesive. For mechanically roughened specimens, Eclipse Bonding Agent (BA) resulted in significantly higher reline bond strength than Secure adhesive. SEM showed different surface appearance of Eclipse resin with various mechanical and chemical preparations.

No Beneficial Effects of Pine Bark Extract on Cardiovascular Disease Risk Factors

Although modifiable cardiovascular disease risk factors are common, some patients eschew conventional drug treatments in favor of natural alternatives. Pine bark extract, a dietary supplement source of antioxidant oligomeric proanthocyanidin complexes, has multiple putative cardiovascular benefits. Studies published to date about the supplement have notable methodological limitations. We randomized 130 individuals with increased cardiovascular disease risk to take 200 mg of a water-based extract of pine bark (n = 64; Toyo-FVG, Toyo Bio-Pharma, Torrance, California; Shinyaku Co, Ltd, Saga, Japan; also marketed as Flavagenol in Japan) or placebo (n = 66) once per day. Blood pressure, our primary outcome, and other cardiovascular disease risk factors were measured at baseline and at 6 and 12 weeks. Statistical analyses were conducted using regression models. Baseline characteristics did not differ between the study groups. Over the 12-week intervention, the sum of systolic and diastolic blood pressures decreased by 1.0 mm Hg (95% confidence interval, -4.2 to 2.1 mm Hg) in the pine bark extract-treated group and by 1.9 mm Hg (-5.5 to 1.7 mm Hg) in the placebo group (P = .87). Other outcomes were likewise not significantly different, including body mass index, lipid panel measures, liver transaminase test results, lipoprotein cholesterol particle size, and levels of insulin, lipoprotein(a), fasting glucose, and high-sensitivity C-reactive protein. There were no subgroups for whom intake of pine bark extract affected cardiovascular disease risk factors. This pine bark extract (at a dosage of 200 mg/d) was safe but was not associated with improvement in cardiovascular disease risk factors. Although variations among participants, dosages, and chemical preparations could contribute to different findings compared with past studies, our results are consistent with a general failure of antioxidants to demonstrate cardiovascular benefits. clinicaltrials.gov Identifier: NCT00425945.

Optimal duration of prophylactic antibiotic administration for elective colon cancer surgery: A randomized, clinical trial

Procedures for perioperative infection prophylaxis in elective colon cancer surgery consist of preoperative mechanical preparation, chemical preparation with oral antibiotic administration, perioperative intravenous antibiotic administration, and others. However, the optimal combination of these procedures and drugs and their durations of administration have not yet been established. A randomized study was conducted to determine the optimal duration of perioperative antibiotic administration with use of mechanical and chemical preparation. A total of 370 patients who were to undergo elective colon cancer surgery were randomized into 2 groups. After mechanical and chemical preparations, a single, 1-g dose of flomoxef was administered immediately before surgery to patients in group A. Flomoxef 1 g was administered twice daily for a total of 4 days from the day of surgery to postoperative day 3 to patients in group B. Comparison was performed between 179 patients in group A and 181 patients in group B with analyzable data. The incidences of incisional surgical site infections (SSIs), organ/space SSIs, and remote infections (RIs) were 15 patients (8.4%), 1 patient (0.6%), and 8 patients (4.5%), respectively, in group A, and 13 patients (7.2%), 2 patients (1.1%), and 6 patients (3.3%), respectively, in group B. There were no differences in the incidence of incisional SSIs, organ/space SSIs, or RIs between groups A and B. It was shown that a single dose of intravenous antibiotic immediately before surgery is sufficient as perioperative infection prophylaxis in elective colon cancer surgery when mechanical and chemical preparation is performed.

THE EFFICIENCY OF BIOLOGICAL PREPARATION ACTOFIT APPLICATION ON HOP AGAINST SPIDER MITE

Spider mite (Tetranychus urticae Koch.). is the most harmful hop pest during the vegetative period. Pest control system foresees 6-8 treatments by different chemical preparations against him. The application of biological preparation Actofit had essentially decreased the pesticide load on hop agricoenosis and had improved the environment situation. Spraying of hop gardens against the spider mite had enabled receipt of high quality cones crop at level 8,2-10,3 c/ha in dependence on doze of preparation which was at level chemical preparation Demitan by quantitative and qualitative indices.

INHIBITORNIH MATTER APPLICATION FOR FIRE PREVENTION ON CONSUMER COAL DEPOLO GREAT FOR ENVIRONMENT PROTECTION

<p>Disposed of in the open air coal is constantly in contact with oxygen from the air, which leads to oxidation of coal in this matter and is released a certain amount of heat. If there are no conditions to the constant heat sinks, warming occurs, then the only inflammatory coal matter. The tendency of matter to carbon just warming up and only inflammatory is different. The tendency of matter to carbon just a warm-up and just broke is different. Especially great propensity just broke show coal with low degree of metamorphosis that is, a high content of volatile matter. Polluting emissions in the ambient environment, in the case of silent or larger fires burning in depou coal, are analyzed in detail to date, although the impact on the environment is very important.</p> <p>The process of oxidation is a natural and constant phenomenon and can not be avoided without taking adequate measures of protection. One of the preventive measures and the application of inhibitornih chemical materials. The possibility of using these preparations is shown in this paper, the experiment was carried out at the dump coal TE Ugljevik, using special preparations. The aim of this experiment was to point out the importance of preventive measures in prevention of oxidation, heating, and only inflammation in the large coal depots, the use of chemical preparations on the basis of inhibition, in order to reduce damage due to loss of coal, the amount of waste matter and protect the environment.</p>

Plasma‐Assisted Approaches in Inorganic Nanostructure Fabrication

Plasma is a unique medium for chemical reactions and materials preparations, which also finds its application in the current tide of nanostructure fabrication. Although plasma-assisted approaches have been long used in thin-film deposition and the top-down scheme of micro-/nanofabrication, fabrication of zero- and one-dimensional inorganic nanostructures through the bottom-up scheme is a relatively new focus of plasma application. In this article, recent plasma-assisted techniques in inorganic zero- and one-dimensional nanostructure fabrication are reviewed, which includes four categories of plasma-assisted approaches: plasma-enhanced chemical vapor deposition, thermal plasma sintering with liquid/solid feeding, thermal plasma evaporation and condensation, and plasma treatment of solids. The special effects and the advantages of plasmas on nanostructure fabrication are illustrated with examples, emphasizing on the understandings and ideas for controlling the growth, structure, and properties during plasma-assisted fabrications. This Review provides insight into the utilization of the special properties of plasmas in nanostructure fabrication.

Structure–Activity Analysis of Semisynthetic Nucleosomes: Mechanistic Insights into the Stimulation of Dot1L by Ubiquitylated Histone H2B

Post-translational modification of histones plays an integral role in regulation of genomic expression through modulation of chromatin structure and function. Chemical preparations of histones bearing these modifications allows for comprehensive in vitro mechanistic investigation into their action to deconvolute observations from genome-wide studies in vivo. Previously, we reported the semisynthesis of ubiquitylated histone H2B (uH2B) using two orthogonal expressed protein ligation reactions. Semisynthetic uH2B, when incorporated into nucleosomes, directly stimulates methylation of histone H3 lysine 79 (K79) by the methyltransferase, disruptor of telomeric silencing-like (Dot1L). Although recruitment of Dot1L to the nucleosomal surface by uH2B could be excluded, comprehensive mechanistic analysis was precluded by systematic limitations in the ability to generate uH2B in large scale. Here we report a highly optimized synthesis of ubiquitylated H2B bearing a G76A point mutation u(G76A)H2B, yielding tens of milligrams of ubiquitylated protein. u(G76A)H2B is indistinguishable from the native uH2B by Dot1L, allowing for detailed studies of the resultant trans-histone crosstalk. Kinetic and structure-activity relationship analyses using u(G76A)H2B suggest a noncanonical role for ubiquitin in the enhancement of the chemical step of H3K79 methylation. Furthermore, titration of the level of uH2B within the nucleosome revealed a 1:1 stoichiometry of Dot1L activation.

Chinese Slimming Capsules Containing Sibutramine Over The Internet—A Case Series: Crude Herbal Drugs May Be Safe

The dubious quality of Chinese drug preparations or food supplements is hardly news. However, this problem affects not only herbal preparations but is a general quality issue in some Asian countries, which also affects chemical preparations (heparin) and food preparations (melamine).

Granulation in technology for utilization of industrial waste materials

Technology is presented for the utilization of dust, captured by electric filters of a cement production rotary kiln, with preparation of granulated potassium-lime fertilizer in a drum pelletizer. The binder used is an aqueous solution of potassium, prepared by mixing sinter dust with water and unconditioned granules in the ratio S:L = 1:5. The size of the dried granules is not more than 5 mm, strength in compression 1.2‐1.6 MPa, and this satisfies the requirements for granulated fertilizer. With the aim of utilizing overburden chalk rocks from iron deposits of the Lebedinskii and Stoilenskii Mining and Concentration Combines granulation technology is developed for chalk as an improver for soil deoxidation. It is established that the most effective binder material is bentonite. The optimum weight of bentonite clay per ton of chalk is 2‐3 kg. The granules obtained satisfy the requirements for a granulated fertilizer with respect to size, strength and moisture content. During development of industrial production in the economic revolution of the country ever greater amounts of natural resources are involved. However, the degree of the rational use is very low. About 70% of industrial expenditure in CIS countries is consumed in feedstock, materials, fuel, electrical energy, and at the same time about 10‐70% of starting materials is converted into waste discharged into the atmosphere or volumes of water. In ferrous and nonferrous metallurgy, and also in the production of fertilizer and chemical preparations obtaining concentrates is an obligatory production operation with which it is necessary to grind natural materials, accompanied by an increase in the dispersion of mineral waste materials (that is undesirable from an ecological point of view) and an increase in the amount of them. With known assumptions, it is possible to confirm that the level of the harmful effect on the natural environment of substances contained in dumps is proportional to their dispersion and volume. The practice of operating tailing and slurry pits indicates that they serve as a source of water and atmospheric contamination. In view of the exhaustion of natural resources, it may be suggested that these pits and dumps with time are converted from objects for burying waste materials into reservoirs for storing unclaimed mineral masses undergoing a specific treatment cycle and containing components that it will be necessary to extract in the future. Aggregation of technogenic powders by granulation may be considered as the next step in converting mineral waste material into a source of conditioned technogenic raw material. In order to store powders in pelletized form, powder with binding properties is mainly recommended, i.e., calcium ashes from thermal power stations, cement kiln dust, etc. [1]. A method has also been proposed in [2] for immobilizing and storing condensed harmful substances by processing them with a protective binder solution (aluminosilicate solution of nepheline in a 10‐20% solution of sulfuric or hydrochloric acid) followed by hardening and molding.

Analysis of grassland associations of Stara Planina mountain

Production of organic, biologically valuable food is a trend in the World today, and in our country it can be successfully realized in production of meat and milk from small ruminants, sheep and goats in hilly-mountainous region. Namely, grasslands in these regions are well preserved from the utilization of mineral fertilizers and chemical preparations for plant protection, therefore production of healthy food is still possible with minimum investments. The quality of plant mass is very important, i.e. presence of high quality plant species in the grassland, as well as possibility for increase of their percentage in the grassland. For this purpose, research was carried out and plant associations most present on Stara Planina Mountain on altitude of 650 to 1200 m were analyzed from the aspect of phytocenology. On these locations recordings were made and samples were taken for analysis in the period 2002-2005 and in year 2008. Total of 8 associations were analyzed, and two of them Agrostietum vulgarae Z. Pavl. 1955. sensu lato. and Festucetum vallesiacae Borisavljevic 1956. occurred repeatedly on several location and different time interval of analysis. Beside mentioned two associations the following were also analyzed: Arrhenatheretum elatioris Br.-Bl. 1925.senso lato, Festuco-Chrysopogonetum grylli Randj. 1977., Danthonietum calycinae Cinc. et Kojic 1958., Medicago falcata-Festucetum rubrae, Trifolio campestre- Agrostietum vulgaris i Festuco vallesiacae-Agrostieutum vulgaris Danon et Blaz.1978 on 17 locations. Number of species in analyzed associations was from 34 to 77. Beside number of plant species also their share categorized in categories of high qualiity grasses, high quality leguminous plants and useful species from other families, as well as harmful i.e. weed species. Main quality parameters were established in samples from all associations. Objective of analyses of natural grasslands was to establish share of high quality plant species, which is reflected directly through production and quality of plant mass grazed by small ruminants, sheep and goats.

Comparative Study of the Adsorption Activity of Medicinal Sorbents

A comparative study of the adsorption activity of some medical sorbents with respect to physiologically active substances with different molecular weights has been carrried out. It is shown that Siliks (Polysorb MP) exhibits greater ability to adsorb proteins in comparison to other sorbents. In contrast, the carbon-based sorbents do not absorb proteins but have a high affinity for low-and medium-molecular-weight substances. The adsorption activity of Smecta in acid media is close to that of carbons. Due to similar chemical properties, the Siliks and Enterosgel preparations demonstrate analogous adsorption characteristics.

Half a Century of Antidepressant Drugs

MILESTONES OF PHARMACOLOGICAL TREATMENT The 50th anniversary of antidepressant pharmacotherapy is worth remembering. We review the onset of drug treatment with convincing antidepressive efficacy in 2 parts, and in this first part, we recapitulate on the development and clinical introduction of monoamine oxidase inhibitors (MAOI). Before the clinical introduction of the first antidepressants, imipramine and iproniazid, the therapeutic choice in dealing with mood disorders was extremely small. In the early 20th century, the agents used were chloral hydrate, barbiturates, amphetamines, and even opiate derivatives in agitated melancholic patients. During the first half of that century biological treatments were insulin coma, chemical and electric shock therapy, or the famous and widespread Bsleep cures.[ Available chemical preparations were only some nonspecific ones, such as succinic dinitrite, malonic nitrite, or lactic acid with rather unsatisfactory antidepressant results. In the 1950s, a veritable revolution took place in the fields of psychopharmacology and psychiatry with the clinical introduction of the main groups of psychoactive substances still used today. Chance played an important role in the discovery of the majority of psychotropic drugs in the early phases of psychopharmacology; in addition, a large dose of wisdom and astute clinical observation3 was truly important to the final results of these research processes. It suffices to highlight, apart from the discovery of imipramine and the psychiatric use of iproniazid, the discovery of the antimanic properties of lithium in 1949, the clinical introduction of chlorpromazine in 1952 and meprobamate in 1954, and, finally, the introduction of chlordiazepoxide in 1960. This contributes to the 1950s being considered to be the Bgolden decade of psychopharmacology.[

Helium-Plasma-Prepared (111)A HgCdTe and (211)B InSb

Brief low-energy helium plasma exposure of mercury cadmium telluride and indium antimonide results in oxide- and elemental-component-free, nearly stoichiometric surfaces. In these initial experiments, the only remaining residue is a topmost trace layer of carbon similar to that present on wet etched and reduced surfaces. The nature of these surfaces was determined by in situ Auger electron spectroscopy, monochromatic X-ray photoelectron, and ion scattering spectroscopy, and compared with established wet chemical and hydrogen argon plasma preparations.