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Journal articles on the topic 'High-pressure spectrophotometry'
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1
Arabas, J., P. Butz, C. Merkel, Z. Spolnicki, J. Szczepek, and B. Tauscher. "Miniature optical cell for spectrophotometry under high pressure." High Pressure Research 19, no. 1-6 (September 2000): 379–83. http://dx.doi.org/10.1080/08957950008202581.
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Duke, Stephen O., Mary V. Duke, Timothy D. Sherman, and Ujjana B. Nandihalli. "Spectrophotometric and Spectrofluorometric Methods in Weed Science." Weed Science 39, no. 3 (September 1991): 505–13. http://dx.doi.org/10.1017/s004317450007329x.
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The utility, advantages, and disadvantages of several spectrofluorometric and in vivo spectrophotometric methods in plant science are reviewed, with emphasis on their use in weed science. Examples of the use of in vivo, dual-wavelength spectrophotometry to probe the effects of herbicides on cytochromefoxidation/reduction, the P515 chromatic shift, phytochrome synthesis, and other processes are discussed. Use of in vivo spectrophotometry to examine effects of herbicides on phytylation of chlorophyllide, protochlorophyllide photoconversion, porphyrin accumulation, and other processes that result in spectral changes is discussed and examples are provided. Spectrofluorometric methods for pigment identification and quantification and for enzyme assays are illustrated with examples. Spectrofluorometric methods used in conjunction with high-pressure liquid chromatography (HPLC) and thin-layer chromatography (TLC) are discussed.
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Webb, D. J., B. K. Burnison, A. M. Trimbee, and E. E. Prepas. "Comparison of Chlorophyll a Extractions with Ethanol and Dimethyl Sulfoxide/Acetone, and a Concern about Spectrophotometric Phaeopigment Correction." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 11 (November 1, 1992): 2331–36. http://dx.doi.org/10.1139/f92-256.
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Chlorophyll a (Chl a) in water samples from three mesotrophic to eutrophic lakes in north-central Alberta was extracted with one of three solvents (95% ethanol, 90% ethanol, or a 2:3 mixture of dimethyl sulfoxide and 90% acetone (DMSO/acetone)) and analyzed by two techniques (spectrophotometry and high pressure liquid chromatography (HPLC). The dominant phytoplankton were blue-green algae and diatoms. Total Chl a concentrations (i.e. no correction for phaeopigments (Pha)) were not significantly different among solvents (P > 0.5). Total Chl a concentrations from spectrophotometric analyses were significantly higher than those from HPLC analyses (4.2 ± 0.88 and 2.6 ± 0.50 μg∙L−1 respectively, P < 0.05). Pha concentrations derived by spectrophotometry were 64 times higher than those derived by HPLC (1.7 ± 0.52 and 0.025 ± 0.01 μg∙L−1 respectively, P < 0.005). Thus, spectrophotometry appears to dramatically overestimate Pha concentrations and may overestimate total Chl a (i.e. no correction for Pha). Therefore, ethanol and DMSO/acetone are equally suitable for Chl a extraction from natural populations dominated by blue-green algae and/or diatoms, but if information on Pha and/or accessory pigments is required, HPLC analyses are the appropriate route rather than spectrophotometry.
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Suleimenov, O. M. "Simple, compact, flow-through, high temperature high pressure cell for UV-Vis spectrophotometry." Review of Scientific Instruments 75, no. 10 (September 24, 2004): 3363–64. http://dx.doi.org/10.1063/1.1791317.
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Hu†, Ye, Hao Liang†, Qipeng Yuan, and Yuancheng Hong. "Determination of glucosinolates in 19 Chinese medicinal plants with spectrophotometry and high-pressure liquid chromatography." Natural Product Research 24, no. 13 (August 15, 2010): 1195–205. http://dx.doi.org/10.1080/14786410902975681.
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Afandy, Moh A., Wahyudi B. Sediawan, Muslikhin Hidayat, Devi Y. Susanti, and Fikrah D. I. Sawali. "Bioactive Compound Contents and Antioxidant Activity of Purified Red Sorghum Pericarp Extract by Membrane Ultrafiltration Process." Jurnal Akademika Kimia 12, no. 1 (February 28, 2023): 13–19. http://dx.doi.org/10.22487/j24775185.2023.v12.i1.pp13-19.
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Sorghum plants contain bioactive compounds such as phenolic compounds and proanthocyanidins. The presence of these compounds is extremely valuable for use as antioxidants in health care. This study aims to determine the total phenolic content, total proanthocyanidin content, and antioxidant activity of purified red sorghum extract using the ultrafiltration membrane method with different transmembrane pressure. At pressures of 8, 9, and 10 Bar, an ultrafiltration process was carried out using a polyethersulfone (PES) membrane with a molecular weight cut-off size of 10 kDa. The total phenolic content was determined using the Follin-Ciocalteu method and identified using UV-Vis spectrophotometry at 760 nm. Total proanthocyanidin content was measured using the acid-butanol method and then analyzed using UV-Vis spectrophotometry at 550 nm. The DPPH (2,2-diphenyl-2-picrylhydrazyl) method will be used to determine the antioxidant activity of purified red sorghum extract. The results of the measurements show that the higher the transmembrane pressure, the higher the concentration of phenolic and proanthocyanidins content, and that the purified red sorghum extract has a high antioxidant value (IC 50 = 66.852 ppm).
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Pick, Frans E., Pieter R. De Beer, Susan M. Prinsloo, and Louis P. Van Dyk. "Contaminant and formulation analysis of MSMA using high-pressure liquid chromatography - graphite furnace atomic absorption spectrophotometry." Pesticide Science 21, no. 1 (1987): 45–49. http://dx.doi.org/10.1002/ps.2780210105.
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Von Fischern, T., S. Langefeld, L. Yuan, N. Völcker, M. Reim, B. Kirchhof, and N. F. Schrage. "The “Aachen” keratoprosthesis: A New Approach towards Successful Keratoprosthesis-Surgery." International Journal of Artificial Organs 21, no. 1 (January 1998): 52–57. http://dx.doi.org/10.1177/039139889802100111.
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Background None of the keratoprostheses available today is absolutely successful in the long term, neither the problems of extrusion, retroprosthetic membrane formation and intraocular pressure rise are yet solved. A new type of keratoprosthesis is required which can show improved ingrowth characteristics and allow intraocular pressure measurements. In order to possibly meet the above mentioned requirements we developed a flexible silicone keratoprosthesis with scleral fixation and chemical surface modification. Methods The one-piece keratoprosthesis is made of silicone rubber. Its optical zone has a diameter of 11 mm and is 0.3 mm thick. The surface-modified haptic consists of a scleral rim and eight branches for scleral fixation. A ridge at the back of the keratoprosthesis fitting into the trephination hole shall avoid leakage and retroprosthetic membrane formation. Optical and mechanical qualities are characterised by tensile tests, spectrophotometry and topography. Results A method for keratoprosthesis-production was established. The optical quality of the device was improved by submicron lathing of the mould. Spectrophotometry showed high visible and ultraviolet light transmission of the silicone. Mechanical tests with silicone samples revealed high tensile strength and elongation at break. The mechanical properties were not impaired by surface modification. Conclusions The production of a flexible silicone keratoprosthesis with high optical and mechanical properties was established. Its use both for the treatment of permanently opacified corneas and as temporary keratoprosthesis seems to be possible.
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Einhorn, Todd C., Cecil Stushnoff, Ann E. McSay, Phil L. Forsline, Sam Cox, Joel R. L. Ehrenkranz, and Loretta Sandoval. "(18) Biodiversity of the Flavonoid Phlorizin in a Subset of the USDA Apple Germplasm Core Collection." HortScience 40, no. 4 (July 2005): 1067D—1067. http://dx.doi.org/10.21273/hortsci.40.4.1067d.
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Phlorizin is known for its role in reducing glucotoxicity and has a long history of use in diabetes research. In addition, its contribution to the pool of total phenolics adds to the overall health benefits attributed to fruit. Phlorizin is limited to Rosaceae family plants, of which apple comprises its current commercial source; however, limited information exists regarding its biodiversity among apple taxa. A subset of 22 taxa from a core collection of apple accessions representative of the global genetic diversity of apple was used to investigate the biodiversity of phlorizin present in apple shoots and in fruit relative to total phenolic content and free radical scavenging capacity. Fruit and shoots were harvested from the USDA Plant Genetic Resources Unit in Geneva, N.Y. Validation and quantification of phlorizin was conducted using a rigorous high-pressure liquid chromatography (HPLC) procedure. Total phenolics in fruit, assayed using a Folin-Ciocalteu method and expressed as gallic acid equivalents, ranged from 227 to 7181 mg·L-1 and were strongly related to 2,2' azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) antioxidant capacity for the core collection (r= 0.778). On a molar basis, phlorizin had lower antioxidant capacity than other major phenolic compounds present in apple fruit, but was more effective than ascorbic acid. Phlorizin yield in dormant apple shoots, expressed as percent weight, ranged from 0.9% to 5.5%. A rapid, 96 well micro-plate spectrophotometric assay was also developed to aid in the screening of multiple samples for selection of high phlorizin yielding apple taxa. Spectrophotometry overestimated phlorizin content as expected, but the calibration curve between HPLC and spectrophotometry was acceptable, r2 = 0.88.
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Mao, Xiao Jing, Ye Hong Shi, and Hua Chang Li. "Comments on Technical Progress in Pretreatment and Analysis Method of Inorganic Elements of Electroplating Sludge." Advanced Materials Research 1010-1012 (August 2014): 413–16. http://dx.doi.org/10.4028/www.scientific.net/amr.1010-1012.413.
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The latest technical progress in pretreatment and analysis method of inorganic elements of electroplating sludge was briefly reviewed. Some pretreatment methods were summarized, including exposure system digestion, high-pressure tank digestion, microwave digestion and dry ash digestion as well as some analysis methods, such as spectrophotometry, atomic absorption spectrometry, inductively coupled plasma spectrometry and inductively coupled plasma mass spectrometry. Finally, the trend for future technical development in inorganic elements determination of electroplating sludge was prospected.
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Pasák, Michael, Marie Vanišová, Lucie Tichotová, Jana Křížová, Taras Ardan, Yaroslav Nemesh, Jana Čížková, et al. "Mitochondrial Dysfunction in a High Intraocular Pressure-Induced Retinal Ischemia Minipig Model." Biomolecules 12, no. 10 (October 21, 2022): 1532. http://dx.doi.org/10.3390/biom12101532.
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Purpose: Retinal ischemia (RI) and progressive neuronal death are sight-threatening conditions. Mitochondrial (mt) dysfunction and fusion/fission processes have been suggested to play a role in the pathophysiology of RI. This study focuses on changes in the mt parameters of the neuroretina, retinal pigment epithelium (RPE) and choroid in a porcine high intraocular pressure (IOP)-induced RI minipig model. Methods: In one eye, an acute IOP elevation was induced in minipigs and compared to the other control eye. Activity and amount of respiratory chain complexes (RCC) were analyzed by spectrophotometry and Western blot, respectively. The coenzyme Q10 (CoQ10) content was measured using HPLC, and the ultrastructure of the mt was studied via transmission electron microscopy. The expression of selected mt-pathway genes was determined by RT-PCR. Results: At a functional level, increased RCC I activity and decreased total CoQ10 content were found in RPE cells. At a protein level, CORE2, a subunit of RCC III, and DRP1, was significantly decreased in the neuroretina. Drp1 and Opa1, protein-encoding genes responsible for mt quality control, were decreased in most of the samples from the RPE and neuroretina. Conclusions: The eyes of the minipig can be considered a potential RI model to study mt dysfunction in this disease. Strategies targeting mt protection may provide a promising way to delay the acute damage and onset of RI.
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Mijin, Dusan, Vuk Tomic, and Branimir Grgur. "Electrochemical decolorization of the reactive orange 16 dye using dimensionally stable Ti/PtOx anode." Journal of the Serbian Chemical Society 80, no. 7 (2015): 903–15. http://dx.doi.org/10.2298/jsc140917107m.
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Electrochemical decolorization of the Reactive Orange 16 was studied using dimensionally stable Ti/PtOx anode in the chloride containing solution. Different reaction parameters, agitation speed, applied current, sodium chloride concentration, and dye concentration was varied and optimum electrolysis conditions were suggested. The hypohlorous acid was suggested to be an active species in the electrochemical decolorization. Reaction was also studied using UV-Vis spectrophotometry, high-pressure liquid chromatography (HPLC), and total organic carbon (TOC) and total nitrogen (TN) analyses.
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Fitriani, Perti, and Davit Nugraha. "Albumin Identification in Catfish ( Clarias sp ) Using Spectrophotometry UV-VIs." Ad-Dawaa : Journal of Pharmacy 1, no. 1 (May 17, 2023): 29–36. http://dx.doi.org/10.52221/dwj.v1i1.223.
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Albumin is a simple protein with globular protein molecules. Albumin is water soluble and can be coagulated with heat. Albumin solution in water can be precipitated by adding ammonium sulfate until saturated. Albumin functions to regulate the osmotic pressure in the blood, maintain the presence of water in the blood plasma so that it can maintain the volume of blood in the body and as a means of transportation and transportation. Catfish contains 15.6 grams of high-quality protein in each fish so that it can meet the needs of the amino acids needed by the body. The high-quality protein in catfish helps the body build lean brain mass and the protein content in catfish also helps increase the effectiveness of immune function. The purpose of this study was to determine albumin levels in catfish by extracting catfish meat using the oven method and determining the maximum albumin wavelength. In the identification test with the heating method and UV-Vis spectrophotometry test. This research method uses the experimental method. The extraction results were then heated in an oven to observe coagulation and determine the wavelength using UV-Vis spectrophotometry using Bovine Serum Albumin (BSA) as a reference solution and Bromocressol green as a reagent. The conclusion of this study is that catfish meat extract was coagulated using the oven method and maximum absorption was obtained at a wavelength of 625 nm using UV-Vis spectrophotometry.
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Schwenger, Katherine J. P., Bianca M. Arendt, Marek Smieja, David W. L. Ma, Fiona Smaill, and Johane P. Allard. "Relationships between Atherosclerosis and Plasma Antioxidant Micronutrients or Red Blood Cell Polyunsaturated Fatty Acids in People Living with HIV." Nutrients 11, no. 6 (June 7, 2019): 1292. http://dx.doi.org/10.3390/nu11061292.
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Background: People living with human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) (PLWH) are at an increased risk of cardiovascular disease. Diet-related factors may contribute. The aim of this pilot study was to determine, in PLWH, the relationship between atherosclerosis assessed by carotid intima-media thickness (CIMT) and (A) plasma antioxidant micronutrients and oxidative stress or (B) red blood cell polyunsaturated fatty acids (RBC PUFA), particularly long chain omega-3 polyunsaturated fatty acids (n-3 PUFA). Methods: (A) In a cross-sectional study, subjects had CIMT evaluated by high resolution carotid artery ultrasound. Plasma was collected for vitamin C, measured by spectrophotometry; and alpha- and gamma-tocopherol, retinol, and malondialdehyde—a marker of oxidative stress—using high pressure liquid chromatography and fluorescence spectrophotometry. (B) In a prospective cohort study, other subjects had RBC PUFA measured at baseline, using gas chromatography, and CIMT assessed at baseline and repeated after 2 years. Clinical data was also collected. Results: (A) 91 PLWH participated. Only alpha- and gamma-tocopherol levels were positively correlated with CIMT. In a multivariate analysis, age and systolic blood pressure were significantly associated with CIMT with gamma-tocopherol near significance (p = 0.053). (B) 69 PLWH participated. At baseline, docosahexaenoic acid (n-3 PUFA) and the ratio of docosahexaenoic acid to arachidonic acid (n-6 PUFA) were significantly and negatively correlated with CIMT. However, a multivariate analysis failed to detect a significant relationship either at baseline or 2 years after. Conclusion: In addition to age and systolic blood pressure, atherosclerosis assessed by CIMT might be associated with higher serum gamma-tocopherol levels. There was a non-significant association between CIMT and RBC n-3 PUFA or the ratio of n-3 to n-6 PUFA.
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Ghafurian Nasab, Atefe, Sayed Ali Mortazavi, Farideh Tabatabaei Yazdi, and Mahboobe Sarabi Jamab. "Optimization of Gamma Aminobutyric Acid Production Using High Pressure Processing (HPP) by Lactobacillus brevis PML1." BioMed Research International 2022 (January 13, 2022): 1–9. http://dx.doi.org/10.1155/2022/8540736.
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In the present research, the production potential of gamma aminobutyric acid (GABA) using Lactobacillus brevis PML1 was investigated. In addition, the microorganism viability was examined in MAN, ROGOSA, and SHARPE (MRS) after undergoing high hydrostatic pressure at 100, 200, and 300 MPa for 5, 10, and 15 min. Response surface methodology (RSM) was applied to optimize the production conditions of GABA as well as the bacteria viability. Analysis of variance (ANOVA) indicated that both the independent variables (pressure and time) significantly influenced the dependent ones (GABA and bacteria viability) ( P < 0.05 ). The optimum extraction conditions to maximize the production of GABA included the pressure of 300 MPa and the time of 15 min. The amount of the compound was quantified using thin-layer chromatography (TLC) and spectrophotometry. For the process optimization, a central composite design (CCD) was created using Design Expert with 5 replications at the center point, whereby the highest content of GABA was obtained to be 397.73 ppm which was confirmed by high performance liquid chromatography (HPLC). Moreover, scanning electron microscopy (SEM) was utilized to observe the morphological changes in the microorganism. The results revealed that not only did have Lactobacillus brevis PML1 the potential for the production of GABA under conventional conditions (control sample) but also the content of this bioactive compound could be elevated by optimizing the production parameters.
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Nixon, D. E., and T. P. Moyer. "Arsenic Analysis II: Rapid Separation and Quantification of Inorganic Arsenic Plus Metabolites and Arsenobetaine from Urine." Clinical Chemistry 38, no. 12 (December 1, 1992): 2479–83. http://dx.doi.org/10.1093/clinchem/38.12.2479.
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Abstract We describe the rapid separation of inorganic arsenic plus metabolites from arsenobetaine or seafood arsenic in urine. Traditional, high-pressure liquid chromatography is replaced by disposable silica-based cation-exchange cartridges for this separation. Both fractions are quickly separated and collected for analysis by atomic absorption spectrophotometry. Analytical recovery of both fractions is > or = 95%, with an overall precision (CV) ranging from 1.6% to 6.4%. Using this method, we correctly identified the sources of arsenic exposure, whether of inorganic or seafood origin, in 11 urine specimens supplied by the Centre de Toxicologie du Quebec.
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Barre, Douglas E., Kazimiera A. Mizier-Barre, Odette Griscti, and Kevin Hafez. "Relationships of apolipoprotein E genotypes with a cluster of seven in persons with type 2 diabetes." Endocrine Regulations 58, no. 1 (January 1, 2024): 40–46. http://dx.doi.org/10.2478/enr-2024-0005.
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Abstract Objective. The objective of the study was to determine if there would be statistically significant differences or trends among apolipoprotein E genotypes (2/2, 2/3, 2/4, 3/3, 3/4, and 4/4) for each member of the cluster of seven associated with type 2 diabetes (T2D). The cluster of seven includes abdominal obesity, hypertension, platelet hyperaggregability, hyperglycemia, dyslipidemia (decreased plasma levels of high-density lipoprotein cholesterol (HDL-C) and increased plasma levels of triglycerides)), increased low-density lipoprotein (LDL) oxidation, and increased inflammation. Methods. Forty-six patients with well-controlled T2D participated in the study. Abdominal obesity (assessed by waist circumference), hypertension (measured by manual sphygmomanometry), platelet hyperaggregability (measured by bleeding time), hyperglycemia (by enzymatic kit and spectrophotometry), decreased plasma levels of HDL-C and increased plasma levels of triglycerides (by enzymatic kit and spectrophotometry), increased LDL oxidation (measured by LDL conjugated dienes using spectrophotometry) and increased inflammation measured by C-reactive protein (CRP) (by EIA kit) were determined. Results. All genotypes, except 2/2 were found in the population studied. Abdominal obesity did not vary significantly across the five genotypes. However, glucose levels trended progressively higher going from 2/3 to 2/4 to 3/4 to 4/4. Systolic blood pressure was higher in 3/4 compared to 2/4 and trended higher in 3/4 compared to 3/3. Diastolic blood pressure trended higher in 3/3 vs 2/4 and significantly higher in 3/4 compared to 2/4. Triglycerides trended higher in 3/4 vs 3/3 while HDL-C came close to trending downward in 4/4 compared to 2/4. Bleeding time was unaffected by genotype. Plasma LDL conjugated dienes trended higher in 3/4 vs 2/4 and were significantly higher in 3/4 vs 3/3. CRP trended higher in 4/4 vs 2/3. Conclusion. We can conclude that those with at least one 4 allele in the presence of another allele being 2, 3 or 4 is potentially (in the case of trends) deleterious or is deleterious in terms of hyperglycemia, hypertension (systolic and diastolic blood pressure), dyslipidemia, LDL conjugated dienes and CRP levels.
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Shi, Yixin, Ping Jiang, Fujie Wang, and Shuxian Zhou. "Experimental Study on Mixing Uniformity of Injection On-Line Mixer of Crop Protection Equipment." International Journal of Heat and Technology 39, no. 4 (August 31, 2021): 1143–52. http://dx.doi.org/10.18280/ijht.390412.
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In order to promote pesticide application reduction and efficiency enhancement, to avoid the direct mixing of pesticides caused by secondary pollution and life safety risksand, further improve the mixing uniformity of on-line mixing system of crop protection equipment. The numerical simulation on structural parameters and fluid parameters of the mixer was performed by the CFD method to determine the best structural parameters of the mixer. And an injection online mixing system experiment platform was built. The experiments were carried out by high speed photography and spectrophotometry respectively. The experimental results show as following: The variable mixing ratio experiment was carried out in the case of pure reagents mixing test in the mixer. When the water flow is 140 L/min and the pesticide pressure is 1 MPa, the ratio of pesticide solution is controlled in the range of 1:300 ~ 1:3000, and the images of pesticide entering the mixer are collected respectively. The results of image analysis and processing show that the online mixing system has good mixing performance in qualitative analysis. When the mixing ratio is 1:300 to 1:300 and the normal pressure of pesticide is 0.1 MPa, the maximum mixing uniformity variation coefficient of the pesticide solution is 6.87%. When the mixing ratio is 1:300, the minimum mixing uniformity coefficient is 3.33%. It is proved that the overall trend of mixing uniformity variation coefficient increases with the increase of mixing ratio when the pesticide is mixed at normal pressure. When mixing under pressure, the mixing uniformity coefficient of variation is less than 5% and the maximum is 3.903%, which indicates that the mixing uniformity of the mixer is well when mixing under pressure. The results can improve pesticide utilization, safety of plant protection, reduce secondary pollution and reduce pesticide residues. Through the qualitative analysis of high-speed photography, it is found that the drug mixer has good time and space distribution uniformity in the process of drug mixing. The quantitative detection of spectrophotometry shows that the drug liquid has good time and space distribution uniformity after passing through the mixer. The conclusion of this paper has certain guiding function and reference value for plant protection technology and liquid on-line mixing in chemical and pharmaceutical fields.
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Feng, Fa-mei, Fu-an Liu, Shu-lan Cai, and Jia-qing Xie. "The Catalytic Oxidation of Aqueous Phenol by H2O2Using a Macrocyclic (N-Donor) Cobalt(Ii) Complex." Progress in Reaction Kinetics and Mechanism 36, no. 4 (November 2011): 342–51. http://dx.doi.org/10.3184/146867811x13103063934140.
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A new macrocyclic (N-donor) cobalt(II) complex, denoted CoR, was synthesized and characterized, and used as a mimetic peroxidase in the catalytic oxidation of phenol by H2O2. The catalytic system displayed high catalytic activity and the catalytic character of a metalloenzyme, although it did not attain the catalytic efficiency of enzymes. The final products were maleic and oxalic acids. Intermediate products, such as catechol and hydroquinone and p-benzoquinone, were detected by high-pressure liquid chromatography (HPLC) and UV-Vis spectrophotometry. The effects of temperature and the pH of the system on the rate of the catalytic oxidation were investigated. A reaction mechanism and kinetic model for the catalytic oxidation are proposed, which are supported by the results of the experimental and calculation data.
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Savaj, Bhadresh V., Ashutoshkumar Patidar, and Hasumati A. Raj. "Analytical Techniques for Determination of Hydrochlorothiazide and its Combinations: A Review." International Journal of Advances in Scientific Research 1, no. 3 (April 30, 2015): 114. http://dx.doi.org/10.7439/ijasr.v1i3.1786.
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Hydrochlorothiazide is chemically 6-chloro-1, 1-dioxo-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-7-sulfonamide. Hydrochlorothiazide is a diuretic drug used for treatment of high blood pressure(hypertension) and accumulation of fluid (edema). It works by blocking salt and fluid reabsorption from the urine in the kidneys, causing increased urine output (dieresis). Hydrochlorothiazide is used to treat excessive fluid accumulation and swelling (edema) of the body caused byheart failure, cirrhosis, chronickidney failure, corticosteroid medications, and nephrotic syndrome. It can be used alone or in conjunction with otherblood pressure lowering medicationstotreat high blood pressure.This review focuses on the recent developments in analytical techniques for estimation of Hydrochlorothiazide alone or in combinations with other drugs in various biological media like human plasma and urine. This review will critically examine the (a) sample pretreatment method such as solid phase extraction (SPE), (b) separation methods such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), ultra performance liquid chromatography (UPLC), high performance thin layer chromatography (HPTLC), liquid chromatography coupled to tandem mass spectrometry (LC-MS) and capillary electrophoresis (CE), (c) other methods such as spectrophotometry, diffuse reflectance near infrared spectroscopy and electrochemical methods.
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Swaddle, T. W. "Inorganic solution chemistry at elevated pressures." Canadian Journal of Physics 73, no. 5-6 (May 1, 1995): 258–66. http://dx.doi.org/10.1139/p95-037.
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Recent interest in pressure effects on inorganic systems in solution has been centred upon the use of volumes of activation ΔV‡ as criteria of reaction mechanism. Work in our laboratory has sought to determine whether ΔV‡ is indeed a useful parameter in this respect, i.e., whether it is substantially independent of pressure and reaction conditions and whether it can be quantitatively predicted for suitably "simple" reactions. For solvent exchange on metal ions (the simplest conceivable substitution process), a semi-empirical model predicts ΔV‡ for limiting dissociative (bond breaking) and associative (bond making) mechanisms in water, but experimental values lie between these extremes, vindicating the Langford–Gray "interchange" model in which associative and dissociative processes are viewed as being concerted. For adiabatic electron transfer reactions of the outer-sphere type (the simplest conceivable oxidation–reduction process) in water, an adaptation of Marcus theory accounts for the essentially pressure-independent ΔV‡ satisfactorily, and failures of such predictions can be ascribed to complications such as nonadiabaticity or the incursion of inner-sphere (ligand-bridged) reaction pathways. The theory is less successful in nonaqueous solvents. Experimental methods used for these and related studies include high pressure adaptations of nuclear magnetic resonance, UV–visible spectrophotometry, stopped-flow techniques, cyclic voltammetry, and sampling under pressure.
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Jin, Bo, Zhi Wei Chen, and Shi Qiang Zhu. "Development of an In Situ Analyzer for Iron in Deep Sea Environment." Advanced Materials Research 694-697 (May 2013): 1187–91. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.1187.
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This study presents the development of an in-situ analyzer, ‘IonConExplorer’, which can detect iron concentration in deep seawater at maximum 4000 meters with the method of spectrophotometry coupling with liquid waveguide capillary cell. The detection of limit is 27.25nM (n=20) for Fe(II) at 562nm, while the linear range is 100 nM - 1 μM. On the whole linear range, relative standard deviation of the seven replicate measurements is less than 2%. IonConExplorer is composed of pressure house and equipressure house containing control unit and fluid system, respectively. Via TCP protocol of network communication protocol(TCP/IP) when connecting to the ocean observing network, IonConExplorer transfers abundant real time data instantly to the shore-based station, demonstrating high temporal and spatial distribution resolution of iron.
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Figliuzzi, M. M., S. Sestito, D. Pacifico, L. Parentela, and Carlo Rengo. "Relationship between Macrovascular and Microvascular Hemodynamics Assessed by Spectrophotometry in Periodontal Diseases." International Journal of Dentistry 2021 (June 3, 2021): 1–4. http://dx.doi.org/10.1155/2021/9925198.
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Objective. The aim of this study is to identify a possible link between macrovascular hemodynamic status and microvascular hemodynamic indices in patients with periodontal disease. Methods and Materials. Seventeen adult patients are recruited on a voluntary basis at the Dentistry Department of the “Mater Domini” University of Catanzaro, with sampling that determines the lipid profile, blood glucose, inflammatory mediators, blood plasma viscosity: anamnesis, blood pressure measurement, and detection of anthropometric parameters: eco-Doppler of the carotid arteries and brachial arteries with noninvasive measurements of hemodynamics and evaluation of inflammation and periodontal circulation with a noninvasive spectroscopic technique. The subjects underwent a dental inspection with periodontal proves. The different indices of periodontal disease were evaluated. Results. The sites with high probing depth differ from the healthy ones, showing low oxygen saturation and a notable increase in tissue edema, but no correlation between macro- and microvascular values was found. Conclusion. Periodontal probing and spectroscopic examination showed the correlation between low oxygen saturation levels and tissue edema values with probing depth; however, no correlation between macrovascular hemodynamic status and microvascular hemodynamics indices was found probably given the heterogeneity of the population under consideration, the low number of data gathered, and the small sample size.
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Pak, Oleg, Adel G. Bakr, Mareike Gierhardt, Julia Albus, Ievgen Strielkov, Florian Kroschel, Timm Hoeres, et al. "Effects of carbon monoxide-releasing molecules on pulmonary vasoreactivity in isolated perfused lungs." Journal of Applied Physiology 120, no. 2 (January 15, 2016): 271–81. http://dx.doi.org/10.1152/japplphysiol.00726.2015.
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In addition to its renowned poisonous effects, carbon monoxide (CO) is being recognized for its beneficial actions on inflammatory and vasoregulatory pathways, particularly when applied at low concentrations via CO-releasing molecules (CO-RMs). In the lung, CO gas and CO-RMs are suggested to decrease pulmonary vascular tone and hypoxic pulmonary vasoconstriction (HPV). However, the direct effect of CO-RMs on the pulmonary vasoreactivity in isolated lungs has not yet been investigated. We assessed the effect of CORM-2 and CORM-3 on the pulmonary vasculature during normoxia and acute hypoxia (1% oxygen for 10 min) in isolated ventilated and perfused mouse lungs. The effects were compared with those of inhaled CO gas (10%). The interaction of CORM-2 or CO with cytochrome P-450 (CYP) was measured simultaneously by tissue spectrophotometry. Inhaled CO decreased HPV and vasoconstriction induced by the thromboxane mimetic U-46619 but did not alter KCl-induced vasoconstriction. In contrast, concentrations of CORM-2 and CORM-3 used to elicit beneficial effects on the systemic circulation did not affect pulmonary vascular tone. High concentration of CO-RMs or long-term application induced a continuous increase in normoxic pressure. Inhaled CO showed spectral alterations correlating with the inhibition of CYP. In contrast, during application of CORM-2 spectrophotometric signs of interaction with CYP could not be detected. Application of CO-RMs in therapeutic doses in isolated lungs neither decreases pulmonary vascular tone and HPV nor does it induce spectral alterations that are characteristic of CO-inhibited CYP. High doses, however, may cause pulmonary vasoconstriction.
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Olmedilla Arnal, Luis Enrique, Oscar Diaz Cambronero, Guido Mazzinari, José María Pérez Peña, Jaime Zorrilla Ortúzar, Marcos Rodríguez Martín, Maria Vila Montañes, Marcus J. Schultz, Lucas Rovira, and Maria Pilar Argente Navarro. "An Individualized Low-Pneumoperitoneum-Pressure Strategy May Prevent a Reduction in Liver Perfusion during Colorectal Laparoscopic Surgery." Biomedicines 11, no. 3 (March 14, 2023): 891. http://dx.doi.org/10.3390/biomedicines11030891.
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High intra-abdominal pressure (IAP) during laparoscopic surgery is associated with reduced splanchnic blood flow. It is uncertain whether a low IAP prevents this reduction. We assessed the effect of an individualized low-pneumoperitoneum-pressure strategy on liver perfusion. This was a single-center substudy of the multicenter ‘Individualized Pneumoperitoneum Pressure in Colorectal Laparoscopic Surgery versus Standard Therapy II study’ (IPPCollapse–II), a randomized clinical trial in which patients received an individualized low-pneumoperitoneum strategy (IPP) or a standard pneumoperitoneum strategy (SPP). Liver perfusion was indirectly assessed by the indocyanine green plasma disappearance rate (ICG–PDR) and the secondary endpoint was ICG retention rate after 15 min (R15) using pulse spectrophotometry. Multivariable beta regression was used to assess the association between group assignment and ICG–PDR and ICG–R15. All 29 patients from the participating center were included. Median IAP was 8 (25th–75th percentile: 8–10) versus 12 (12,12) mmHg, in IPP and SPP patients, respectively (p < 0.001). ICG–PDR was higher (OR 1.42, 95%-CI 1.10–1.82; p = 0.006) and PDR–R15 was lower in IPP patients compared with SPP patients (OR 0.46, 95%-CI 0.29–0.73; p = 0.001). During laparoscopic colorectal surgery, an individualized low pneumoperitoneum may prevent a reduction in liver perfusion.
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Luo, Hui. "Anodized Preparation of Titanium Dioxide Nanotube Arrays and Photocatalytic Degradation of Chloramine Phosphorus." Advanced Materials Research 804 (September 2013): 62–66. http://dx.doi.org/10.4028/www.scientific.net/amr.804.62.
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Anodic oxidation processing titanium foil in an aqueous solution of hydrofluoric acid+ glacial acetic acid+polyethylene glycol constant pressure, Synthesized by high-density ordered TiO2nanotube arrays. Calculate the degradation rate of chloramine phosphorus, TiO2nanotubes catalytic performance test.The use of scanning electron microscopy (SEM) and X-ray diffraction (XRD) to characterize the morphology and structure of the nanotubes, Visits oxidation time on the morphology and size of the nanotube arrays, mapping and analysis of current - time curve. An average particle diameter d of the sample may be calculated the strongest diffraction peak of the plane FWHM ,So chloramine phosphorus selection of organic phosphorus drugs for the photocatalytic degradation object, Molybdenum blue spectrophotometry measured and calculated degradation rate, Study of heat treatment temperature and anodizing time photocatalytic degradation, And the sol - gel prepared TiO2 thin film and photocatalytic comparative experiments.
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Eswarudu, M. M., P. Roja, P. Ravi Sankar, and P. Srinivasa Babu. "An Updated Review On Analytical Methods For Estimation Of Azelnidipine And Telmisartan." Asian Journal of Pharmaceutical Research and Development 10, no. 2 (April 15, 2022): 59–76. http://dx.doi.org/10.22270/ajprd.v10i2.1108.
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High blood pressure, also called hypertension, is a common condition that is characterized by having a higher amount of pressure in blood vessels than normal. Hypertension (HT) is a very common disorder, particularly past middle age. It is not a disease in itself, but is an important risk factor for cardiovascular mortality and morbidity. For improvement activity of hypertension, Azelnidipine and Telmisartan newer combination in market, which is effective in Hypertension. This combination was developed to improve medication for Stage II Hypertension. Azelnidipine is Ca2+ channel blocker and chemically 3-[1-(Benzyldrylazetidin-3-yl] 5-isopropyl- 2- amino 6 methyl-4-(3-nitrophenyl)-1,4- dihydropyridine-3, 5dicarboxylate.Telmisartan is AT1-receptor blocker and Chemically2-{4-[[4-methyl-6-(1-methylbenzimidazol-2yl)-2–propylbenzimidazol-1yl] methyl] biphenyl)-benzoic acid. It provides information about different analytical method development like UV spectrophotometry, HPTLC, HPLC, and LC-MS methods reported for Azelnidipine and Telmisartan for individual and other drug combination. All reported methods found to be simple, accurate, economic, precise and reproducible in nature. This Review focuses on recent development in analytical method development for Azelnidipine and Telmisartan, and there were two methods reported for this combination as per our knowledge.
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Kovalchuk, Valentyn P., Oleksandr A. Nazarchuk, Vita M. Burkot, Nadiia S. Fomina, Zoіa M. Prokopchuk, and Oleksandr Dobrovanov. "BIOFILM FORMING ACTIVITY OF NON-FERMENTING GRAM-NEGATIVE BACTERIA." Wiadomości Lekarskie 74, no. 2 (2021): 252–56. http://dx.doi.org/10.36740/wlek202102114.
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The aim: To study the influence of chemical, physical factors on the biofilm forming activity of P. aeruginosa, A. baumannii. Materials and methods: Biofilm forming activity of P. aeruginosa (10 isolates) and A. baumannii (10 isolates) was studied in nutrient media of different composition. There was used the method in 96-well crystalline violet staining plates with spectrophotometry (STAT FAX®4300, wavelength of 620 nm). Results: Results showed that in standard medium (trypto-soy broth), strains of P. aeruginosa (90%) and A. baumannii (60%) obtained high biofilm forming activity. A. baumannii formed biofilms even in sterile water. Biofilm forming activity of urease positive P. aeruginosa increased in the medium with 1.0% urea. Both Acinetbacteria and Pseudomonas intensively produced their biofilms in the presence of 5% serum or sub-bacteriostatic concentrations of levofloxacin in the media. High concentrations of sodium chloride inhibited their biofilm activity. Conclusions: Isolates of Acinetobacter and Pseudomonas obtain the protective biofilm-forming ability under such adverse environmental conditions as insufficient nutrients, high osmotic pressure, the presence of antibiotics but at high concentrations sodium chloride biofilm-formation is stimulated only in the first bacteria and suppressed in the second one.
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Daud, Azra Mat, Suzanne McDonald, and Carolyn E. Oldham. "Dissolved organic carbon characteristics in an acidified groundwater-dependent ecosystem." Marine and Freshwater Research 66, no. 7 (2015): 582. http://dx.doi.org/10.1071/mf13215.
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Quantifying and characterising dissolved organic carbon (DOC) is critical to understanding its role in aquatic ecosystems. This is particularly challenging in acidic groundwater-dependent ecosystems, where low pH and high concentrations of Fe affect DOC characterisation. We investigated the variability in DOC concentrations and chemical structure in an acidic wetland, using UV visible spectrophotometry, a range of digestion methods and subsequent TOC analysis, high-pressure size exclusion chromatography (HPSEC) and rapid fractionation techniques. HPSEC results showed that increasing the pH from an original pH 2.3 to a neutral pH reduced the column adsorption of organic carbon, but did not change molecular weight distributions. Principal component analysis suggested that iron concentrations had a more direct effect on molecular structure than pH. The pH, Fe concentrations and DOC characteristics were highly dynamic and spatially variable, and were linked to surface water–groundwater connectivity, as well as horizontal connectivity of surface ponding. The changing pH and Fe concentrations affected DOC concentration and molecular structure with expected effects on bioavailability of DOC.
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El-Khatib, Ahmed M., Mohamed S. Badawi, Gamal D. Roston, Alaa M. Khalil, Ramy M. Moussa, and Moustafa M. Mohamed. "Synthesis and Characterization of Cobalt Nanoparticles Prepared by Arc Discharge Method Using an Ultrasonic Nebulizer." Journal of Nano Research 52 (May 2018): 88–101. http://dx.doi.org/10.4028/www.scientific.net/jnanor.52.88.
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Magnetic cobalt nanostructured was synthesized by a two-stage method. First, a solution of cobalt precursor droplets was prepared by an ultrasonic nebulizer. Second, the arc discharge method between two electrodes in an inert gas at atmospheric pressure is used to obtain the nanostructured cobalt powder. The sample obtained was characterized by X-ray diffraction (XRD). Scanning electron microscope (SEM), High Resolution Transmission Electron Microscope (HR-TEM), UV-Vis Spectrophotometry, zeta potential (ZP) and vibrating sample magnetometer (VSM). The dielectric constant, and AC conductivity of the prepared sample was determined in the frequency range of 4 Hz to 8 MHz. The investigations showed that the Co nanoparticles prepared in this way have smaller and homogeneous nanoparticles with spherical shape morphology with good stability and unique magnetic properties as compared with the bulky one. The dielectric properties analysis shows an enhancement in the dielectric constant and the AC conductivity of the Co nanoparticles.
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Nalini, Calamur Nagarajan, and Nivedhitha Mathivanan. "A Review on Analytical Methods of Irbesartan and its Combinations in Pharmaceutical Dosage Forms." Current Pharmaceutical Analysis 16, no. 8 (September 28, 2020): 1020–29. http://dx.doi.org/10.2174/1573412915666190802164428.
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Pharmaceutical analysis plays an indispensable role in various stages of drug pipeline including drug development, fabrication of formulation, stability studies and quality control. It is also used for characterizing the composition of different dosage forms in quantitative and qualitative ways. Comprehensive literature survey forms the foundation stone for the focused analysis of research activity. Irbesartan is a hypertension antagonist chiefly employed in the treatment of high blood pressure which is an Angiotensin II Receptor blocker. The multiple mixtures of various antihypertensive medicaments raise challenges in the method development and validation. A genuine venture is undertaken to compile the literatures related to the antihypertensive drug Irbesartan published in various peer reviewed journals. HPLC and UV spectrophotometry are the most preferred analytical techniques when compared to other methods. This present review provides an in-depth assortment of various analytical techniques published for Irbesartan and its combinations, which will help the researchers in their future endeavors.
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Mukhopadhyay, Mausumi, and Dhiraj P. Daswat. "Photochemical degradation of 4-chlorophenol in the aqueous phase using peroxyacetic acid (PAA)." Water Science and Technology 67, no. 2 (January 1, 2013): 440–45. http://dx.doi.org/10.2166/wst.2012.591.
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The photochemical degradation of 4-chlorophenol (4-CP) using ultraviolet irradiation (UV) of 6, 12 and 18 W with peroxyacetic acid (PAA) was studied in a batch reactor. The objective of this work was to investigate degradation and mineralization of 4-CP by PAA. The degradation efficiency increased with increasing UV input. The degradation process was also pH and initial PAA concentration dependent. The optimum conditions for the photochemical degradation of 4-CP as UV input, pH and PAA concentration was found to be 18 W, 9.5 and 3,040 ppm. The reaction efficiency decreased with increasing initial 4-CP concentrations. More than 95% mineralization of 4-CP was achieved with the UV/PAA process. The chloride ion concentration and chemical oxygen demand (COD) was evaluated. The chloride ion concentration and COD were decreased gradually with increasing UV input. Samples were analyzed by high pressure liquid chromatography (HPLC), UV spectrophotometry and gas chromatography–mass spectrometry (GC-MS) for residual concentration and identification of final degraded products.
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Daulton, Tyrone L., Brenda J. Little, Kristine Lowe, and Joanne Jones-Meehan. "In Situ Environmental Cell–Transmission Electron Microscopy Study of Microbial Reduction of Chromium(VI) Using Electron Energy Loss Spectroscopy." Microscopy and Microanalysis 7, no. 6 (November 2001): 470–85. http://dx.doi.org/10.1007/s10005-001-0021-3.
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AbstractReduction of Cr(VI) by the bacterium, Shewanella oneidensis (previously classified Shewanella putrefaciens strain MR-1), was studied by absorption spectrophotometry and in situ, environmental cell–transmission electron microscopy (EC-TEM) coupled with electron energy loss spectroscopy (EELS). Bacteria from rinsed cultures were placed directly in the environmental cell of the transmission electron microscope and examined under 100 Torr pressure. Bright field EC-TEM images show two distinct populations of S. oneidensis in incubated cultures containing Cr(VI)O42−: those that exhibit low image contrast and heavily precipitateencrusted cells exhibiting high image contrast. Several EELS techniques were applied to determine the oxidation state of Cr associated with encrusted cells. The encrusted cells are shown to contain a reduced form of Cr in oxidation state +3 or lower. These results demonstrate the capability to determine the chemistry and valence state of reduction products associated with unfixed, hydrated bacteria in an environmental cell transmission electron microscope.
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Bolevich, Stefani, Nevena Draginic, Marijana Andjic, Nevena Jeremic, Sergey Bolevich, Petr F. Litvitskiy, and Vladimir Jakovljevic. "The Effects of DPP4 Inhibitors on Lipid Status and Blood Pressure in Rats with Diabetes Mellitus Type 2." Serbian Journal of Experimental and Clinical Research 20, no. 4 (December 31, 2019): 301–7. http://dx.doi.org/10.2478/sjecr-2019-0037.
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Abstract The aim of the present study was to examine, evaluate and compare the effects of administered dipeptidyl peptidase-4 (DPP4) inhibitors saxagliptin and sitagliptin on lipid status parameters and blood pressure in rats with streptozotocine induced diabetes mellitus type 2. Forty-eight Wistar albino rats were divided randomly into 4 groups: 1. group I: control healthy group; 2. group II: rats with diabetes mellitus type 2; 3. group III: rats with diabetes mellitus type 2+ treated with 0.6 mg/kg of sitagliptin; 4. group IV: rats with diabetes mellitus type 2 treated with 0.45 mg/kg of saxagliptin. The rats from experimental groups were fed with a high-fat diet for 4 weeks and after 6–8 h of starvation received one dose of streptozotocin (STZ) intraperitoneally (25 mg/kg body weight) to induce type 2 diabetes mellitus (T2DM). Animals with fasting glucose above 7 mmol/L and insulin over 6 mmol/L were included in the study as rats with T2DM. Upon completion of the experiments, the blood was collected from the anesthetized animals and serum triglyceride (TG), total cholesterol (TCH), high density lipoprotein (HDL), and low density lipoprotein (LDL) were measured using spectrophotometry and commercial kits. At the beginning of the study and the day before sacrificing animals, the blood pressure and heart rate were measured by a tail-cuff noninvasive method. DPP4 inhibitors, as glucagon-like peptide-1 (GLP-1) agonists, were associated with modest reductions in DBP, LDL-C, TCH, and TGL and significant improvement in HDL, SBP and HR.
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Mac Giolla Eain, Marc, and Ronan MacLoughlin. "In-Line Aerosol Therapy via Nasal Cannula during Adult and Paediatric Normal, Obstructive, and Restrictive Breathing." Pharmaceutics 15, no. 12 (November 27, 2023): 2679. http://dx.doi.org/10.3390/pharmaceutics15122679.
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High-flow nasal oxygen therapy is being increasingly adopted in intensive and home care settings. The concurrent delivery of aerosolised therapeutics allows for the targeted treatment of respiratory illnesses. This study examined in-line aerosol therapy via a nasal cannula to simulated adult and paediatric models with healthy, obstructive and restrictive lung types. The Aerogen Solo vibrating mesh nebuliser was used in combination with the InspiredTM O2FLO high-flow therapy system. Representative adult and paediatric head models were connected to a breathing simulator, which replicated several different states of lung health. The aerosol delivery was quantified at the tracheal level using UV-spectrophotometry. Testing was performed at a range of supplemental gas flow rates applicable to both models. Positive end-expiratory pressure was measured pre-, during and post-nebulisation. The increases in supplemental gas flow rates resulted in a decrease in aerosol delivery, irrespective of lung health. Large tidal volumes and extended inspiratory phases were associated with the greatest aerosol delivery. Gas flow to inspiratory flow ratios of 0.29–0.5 were found to be optimum for aerosol delivery. To enhance aerosol delivery to patients receiving high-flow nasal oxygen therapy, respiratory therapists should keep supplemental gas-flow rates below the inspiratory flow of the patient.
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Bandala, Erick R., and Oscar M. Rodriguez-Narvaez. "On the Nature of Hydrodynamic Cavitation Process and Its Application for the Removal of Water Pollutants." Air, Soil and Water Research 12 (January 2019): 117862211988048. http://dx.doi.org/10.1177/1178622119880488.
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Cavitation is considered a high energy demanding process for water treatment. For this study, we used a simple experimental setup to generate cavitation at a low pressure (low energy) and test it for hydroxyl radical production using a well-known chemical probe as a hydroxyl radical scavenger. The conditions for generating the cavitation process (eg, pressure, flow velocity, temperature, and other significant variables) were used to degrade model contaminants, an azo dye and an antibiotic. The amount of hydroxyl radicals generated by the system was estimated using N,N-dimethyl-p-nitrosoaniline (pNDA) as hydroxyl radical scavenger. The capability of hydrodynamic cavitation (HC) to degrade contaminants was assessed using Congo red (CR) and sulfamethoxazole (SMX) as model contaminants. Different chemical models were analyzed using UV-visible spectrophotometry (for pNDA and CR) and high-performance liquid chromatography (HPLC) (for SMX) after HC treatment under different process conditions (ie, pressure of 13.7 and 10.3 kPa, and flow rates of 0.14 to 3.6 × 10−4 m3/s). No pNDA bleaching was observed for any of the reaction conditions tested after 60 minutes of treatment, which suggests that there was no hydroxyl radical generation during the process. However, 50% degradation of CR and 25% degradation of SMX were observed under the same process conditions, comparable with previously reported results. These results suggest that the process is most likely thermally based rather than radically based, and therefore, it can degrade organic pollutants even if no hydroxyl radicals are produced. Hydrodynamic cavitation, either alone or coupled with other advanced water technologies, has been identified as a promising technology for removing organic contaminants entering the water cycle; however, more research is still needed to determine the specific mechanisms involved in the process and the optimal operation conditions for the system.
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Yánez-Jácome, Gabriela S., David Romero-Estévez, Hugo Navarrete, Karina Simbaña-Farinango, and Pamela Y. Vélez-Terreros. "Optimization of a Digestion Method to Determine Total Mercury in Fish Tissue by Cold Vapor Atomic Fluorescence Spectrophotometry." Methods and Protocols 3, no. 2 (June 23, 2020): 45. http://dx.doi.org/10.3390/mps3020045.
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Several microwave-assisted digestion methods were tested at the Centro de Estudios Aplicados en Química laboratory in Quito, Ecuador, to determine the accuracy and performance efficiency of the mineralization process for the determination of total mercury in fish tissue by cold vapor atomic fluorescence spectrophotometry. The use of MARSEasyPrep high-pressure vessels, low amounts of reagents (1 cm3 HNO3, 1 cm3 H2O2, and 1 cm3 HClO4), an irradiation temperature of 210 °C, and 35 min of mineralization time resulted in accurate performance, with recoveries of certified reference material DORM-4 between 90.1% and 105.8%. This is better than the Association of Official Analytical Chemists 2015.01 method, which has a reported accuracy of 81%. The repeatability precision and intermediate precision were established at three concentration levels (0.167, 0.500, and 0.833 mg·kg−1) and expressed as the percentage of the relative standard deviation ranging from 1.5% to 3.0% and 1.7% to 4.2%, respectively. Further, the method was satisfactorily applied to analyze fortified samples of tilapia (Oreochromis niloticus), with recoveries ranging from 98.3% to 104.3%. The instrumental limits of detection and quantification were 0.118 µg·dm−3 and 0.394 µg·dm−3, respectively.
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Makarova, T. P., Z. R. Khabibrakhmanova, D. I. Sadykova, and Yu M. Chilikina. "The status of element homeostasis in children and adolescents with essential arterial hypertension." Kazan medical journal 93, no. 2 (April 15, 2012): 184–90. http://dx.doi.org/10.17816/kmj2284.
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Aim. To study the features of element homeostasis in children and adolescents with different variants of essential arterial hypertension. Methods. The clinical and functional variant of arterial hypertension was established based on the data of 24-hour monitoring of the arterial blood pressure. Investigation of the element content in the blood serum and daily urine was performed using the method of atomic absorption spectrophotometry. The clearance and the excreted fraction of the investigated elements were measured. Results. Revealed was an increase of the content of lead in the blood serum, an increase in lead excretion with urine, an increase in its clearance and excreted fraction in patients with stable arterial hypertension. It has been shown that for children and adolescents with a variety of clinical and functional variants of arterial hypertension characteristic is an excess of the serum content of a toxic element (lead) over the content of an essential element (zinc), and these changes are most pronounced in the group with stable arterial hypertension. In children and adolescents with the increase in arterial blood pressure registered was a decrease in the content of zinc and magnesium in the blood serum, whereas the disturbances of element homeostasis relate to the metabolic type. The increase in the content of copper and calcium in blood serum of patients with high blood pressure is also a manifestation of the metabolic type of element homeostasis disturbances. Conclusion. The increased level of lead in blood serum in combination with its enhanced excretion may be a cofactor in the development of essential arterial hypertension in childhood and adolescence.
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Craft, D. V., D. J. Lefer, C. E. Hock, and A. M. Lefer. "Significance of production of peptide leukotrienes in murine traumatic shock." American Journal of Physiology-Heart and Circulatory Physiology 251, no. 1 (July 1, 1986): H80—H85. http://dx.doi.org/10.1152/ajpheart.1986.251.1.h80.
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We studied the formation of a leukotriene metabolite in plasma and bile during traumatic shock. Anesthetized rats subjected to Noble-Collip drum trauma developed a lethal shock state characterized by a survival time of 1.9 +/- 0.3 h, a 4.5-fold increase in plasma cathepsin D activity, and a reduction in mean arterial blood pressure to 45 +/- 2 mmHg compared with 108 +/- 5 mmHg in sham-shock controls. Plasma and bile samples were analyzed by reverse-phase high-pressure liquid chromatography (HPLC) for peptide leukotrienes (e.g., LTC4, LTD4, and LTE4), and their retention times were confirmed by co-elution with radioactive standards, radioimmunoassay (RIA), and UV spectrophotometry. No leukotrienes or metabolites were found in plasma. The major peptide leukotriene from bile was eluted between LTC4 and LTD4 and corresponds to a metabolite of LTE4, N-acetyl-LTE4, which is also produced during endotoxin shock. The metabolite increased nearly sevenfold in traumatic shock compared with sham trauma. The identity of the metabolite was confirmed by UV scan, which revealed a spectrum consistent with a peptide leukotriene and similar to that of previously reported spectra for N-acetyl-LTE4. In conclusion, peptide leukotrienes are rapidly cleared from the blood and appear in the bile as N-acetyl-LTE4, a metabolite of the peptide leukotrienes. These findings support a role of the peptide leukotrienes in the pathogenesis of traumatic shock.
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Horyn, M. M., and L. S. Logoyda. "METHODS OF METOPROLOL ANALYSIS IN DRUGS AND BIOLOGICAL FLUIDS: REVIEW AND SUGGESTIONS." International Journal of Medicine and Medical Research 5, no. 2 (February 26, 2020): 88–97. http://dx.doi.org/10.11603/ijmmr.2413-6077.2019.2.10897.
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Background. Analytical method is increasingly implemented into fundamental pharmaceutical chemistry and analysis, considering their high sensitivity, accuracy, specificity and expressiveness.
Objective. Metoprolol’s analytical method development was the research goal.
Methods. The sources were world recognized journals (1990-2019) and key words used as filter were “metoprolol”, “spectrophotometry” “high-performance liquid chromatography, HPLC”, “quantitative analysis”, “validation”.
Results. Chromatographic methods of analysis have the highest specificity and objectivity and allow qualitative and quantitative determination of Active Pharmaceutic Ingredient (API) in combined dosage forms and biological fluids without prior components separation. The main disadvantage of the described API analysis methods is long terms from the beginning of chromatography to API release and specific solvents used as the mobile phase in HPLC. New methods development and selection such chromatographic conditions that provide high speed and high efficiency at lower pressure of the system are essential. Also, the reduction of analysis time is achieved by simplifying the conditions for sample preparation.
Conclusions. Analysts are constantly working on developing new analysis methods and their optimization in order to save time and consumables, which also ensures the efficiency of the developed method. There is no monograph on the substance or dosage forms of metoprolol in SPhU. Therefore, some of the developed methods should be suggested for the SPhU monograph, which is important for ensuring pharmacopoeial quality control of medicines in Ukraine.
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Rérolle, Victoire, Eric Achterberg, Mariana Ribas-Ribas, Vassilis Kitidis, Ian Brown, Dorothee Bakker, Gareth Lee, and Matthew Mowlem. "High Resolution pH Measurements Using a Lab-on-Chip Sensor in Surface Waters of Northwest European Shelf Seas." Sensors 18, no. 8 (August 10, 2018): 2622. http://dx.doi.org/10.3390/s18082622.
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Increasing atmospheric CO2 concentrations are resulting in a reduction in seawater pH, with potential detrimental consequences for marine organisms. Improved efforts are required to monitor the anthropogenically driven pH decrease in the context of natural pH variations. We present here a high resolution surface water pH data set obtained in summer 2011 in North West European Shelf Seas. The aim of our paper is to demonstrate the successful deployment of the pH sensor, and discuss the carbonate chemistry dynamics of surface waters of Northwest European Shelf Seas using pH and ancillary data. The pH measurements were undertaken using spectrophotometry with a Lab-on-Chip pH sensor connected to the underway seawater supply of the ship. The main processes controlling the pH distribution along the ship’s transect, and their relative importance, were determined using a statistical approach. The pH sensor allowed 10 measurements h−1 with a precision of 0.001 pH units and a good agreement with pH calculated from a pair of discretely sampled carbonate variables dissolved inorganic carbon (DIC), total alkalinity (TA) and partial pressure of CO2 (pCO2) (e.g., pHDICpCO2). For this summer cruise, the biological activity formed the main control on the pH distribution along the cruise transect. This study highlights the importance of high quality and high resolution pH measurements for the assessment of carbonate chemistry dynamics in marine waters.
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Jacob, T. D., D. K. Nakayama, I. Seki, R. Exler, J. R. Lancaster, M. A. Sweetland, S. Yousem, et al. "Hemodynamic effects and metabolic fate of inhaled nitric oxide in hypoxic piglets." Journal of Applied Physiology 76, no. 4 (April 1, 1994): 1794–801. http://dx.doi.org/10.1152/jappl.1994.76.4.1794.
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We describe the hemodynamic effects and metabolic fate of inhaled NO gas in 12 anesthetized piglets. Pulmonary and systemic hemodynamic responses to incremental [NO] (5–80 ppm) were tested during ventilation with high- [0.30 inspired O2 fraction (FIO2)] and low-O2 (0.10 FIO2) mixtures. In six animals, inhalation of 40 ppm NO was maintained over 6 h to test effects of prolonged exposure (0.30 FIO2). In the other six animals, pulmonary hypertension was induced by hypoxic ventilation (0.10 FIO2) and responses to NO were tested. Inhaled low [NO] partially reversed pulmonary hypertension induced by alveolar hypoxia; mean pulmonary arterial pressure decreased from 31.4 +/- 2.3 mmHg during hypoxia to 18.2 +/- 1.2 mmHg during 5 ppm NO. Mean pulmonary arterial pressure at 0.10 FIO2 did not fall further at higher [NO] (10–40 ppm) and never reached control levels. Pulmonary vascular resistance increased with institution of hypoxic ventilation and fell with subsequent administration of NO, ultimately reaching control levels. Inhaled NO did not affect systemic vascular resistance. Plasma levels of NO2- + NO3- and methemoglobin (MetHb) levels increased with increasing [NO]. Over 6 h of NO administration during high-O2 ventilation, MetHb equilibrated at subtoxic levels while NO2- + NO3- increased. Nitrosylhemoglobin, analyzed by electron paramagnetic resonance spectrophotometry was not detected in blood at any time. At the relatively low concentrations (5–80 ppm) that are effective in relieving experimental pulmonary hypertension induced by alveolar hypoxia, inhaled NO gas causes accumulation of NO2- + NO3- in plasma and a small increase in MetHb but no detectable nitrosylhemoglobin.
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Boleji, Lesly Aguilar, María Custodio-Villanueva, Fernán Cosme Chanamé Zapata, Walter Javier Cuadrado Campó, and Richard Pavel Peñaloza Fernández. "Bioconcentration and bioaccumulation of toxic metals in Scirpus californicus from natural wetlands in the Central Andes of Peru." Ambiente e Agua - An Interdisciplinary Journal of Applied Science 16, no. 5 (September 22, 2021): 1. http://dx.doi.org/10.4136/ambi-agua.2728.
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Bioconcentration and bioaccumulation levels of lead, zinc, iron and arsenic in Scirpus californicus of the Paca and Tragadero Lagoons, Jauja, Peru, were evaluated. Water, sediment and Scirpus californicus samples were collected from each lagoon, which were transported to the laboratory for the analytical determination of lead, iron, zinc and arsenic, which was performed by atomic absorption spectrophotometry based on the methodology recommended by FAO. The results obtained reveal the current status of the quality of the aquatic environment of natural wetlands in the central region of Peru in terms of heavy metals and arsenic, which provide an important source of water for the populations of large cities in the central region of Peru. The presence of heavy metals and arsenic with great impact on the quality of these water bodies may be due to the pressure exerted by anthropogenic activities such as mining, agriculture, industrial and domestic wastewater. The sediments of Paca and Tragadero Lagoons showed high concentrations of Fe, exceeding international standards. Aquatic vegetation represented by Scirpus californicus in both lagoons bio accumulated mainly Zn, without exceeding international standards.
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Dimiņš, Fredijs, Velga Miķelsone, Ingrīda Augšpole, and Artūrs Niklāvs. "Microwave Facilities for Thermal Treatment of Honey." Key Engineering Materials 800 (April 2019): 103–7. http://dx.doi.org/10.4028/www.scientific.net/kem.800.103.
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Often we are faced with the need for thermal treatment of honey. Traditionally this is done by heating the honey. This process requires certain time consumption. Thermal treatment can be greatly accelerated by the use of microwaves. Indicators for thermal treatment and storage of honey traditionally are hydroxymethylfurfural (HMF) content and activity of enzymes. HMF is organic compound, which is created when carbohydrates are dehydrated. HMF content increases when honey is stored for long time or is thermally treated. Our objective of the study was to find out how the different types of honey heat treatment affect the honey enzyme, invertase, activity and HMF content. HMF content in honey was determined using high pressure liquid chromatography. Invertase activity is determined by spectrophotometry. The study results proved that using microwaves to thermally treat honey significantly impacts honey invertase activity and HMF content increases. Invertase activity reduction is more severe compared to the HMF content increase. Thermally treating honey with microwaves, even treating it only 10 seconds, affects the quality of honey.
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Mauludia, Mauludia, Thamrin Usman, Winda Rahmalia, Dwi Imam Prayitno, and Siti Nani Nurbaeti. "Ekstraksi, Karakterisasi dan Uji Aktivitas Antioksidan Astaxanthin dari Produk Fermentasi Udang (Cincalok)." Jurnal Kelautan Tropis 24, no. 3 (September 5, 2021): 311–22. http://dx.doi.org/10.14710/jkt.v24i3.10497.
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Shrimp is one of the aquatic organisms that contain several active compounds, including astaxanthin. Cincalok is one of the fermented shrimp products containing astaxanthin. This study aims to determine the characteristics of astaxanthin extract from cincalok and its antioxidant activity. Extraction of astaxanthin from cincalok was carried out using the reflux method with acetone : cyclohexane (20:80 v/v) as a solvent. The identification and characterization of astaxanthin was carried out using thin-layer chromatography (TLC), UV-Vis spectrophotometry, and High-Pressure Liquid Chromatography (HPLC). Meanwhile, the antioxidant activity test was carried out using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method in one serial concentration (5; 15; 25 ppm). The results of TLC analysis showed that astaxanthin in cincalok extract has Rf value (0.32). The analysis using a UV-Vis spectrophotometer produced a spectrum with a maximum wavelength of 477 nm, which corresponds to the maximum wavelength of standard astaxanthin. The yield of astaxanthin extract from cincalok in this study was 1.47 mg/100 g wet weight. The chromatogram from the results of UHPLC analysis showed that the retention time of cincalok astaxanthin extract was 6.27 minutes with a purity of 18.03%. The antioxidant activity of cincalok astaxanthin extract was 568.32 ppm. Udang merupakan salah satu organisme air yang mengandung banyak senyawa aktif, termasuk astaxanthin. Cincalok merupakan salah satu produk hasil fermentasi udang yang mengandung astaxanthin. Penelitian ini bertujuan untuk mengetahui karakteristik ekstrak astaxanthin dari cincalok dan aktivitas antioksidannya. Ekstraksi astaxanthin dari cincalok menggunakan metode refluks dengan pelarut aseton:sikloheksan (20:80 v/v). Identifikasi dan karakterisasi astaxanthin dilakukan dengan menggunakan kromatografi lapis tipis (KLT), spektrofotometri UV-Vis, dan High Pressure Liquid Chromatography (HPLC). Sedangkan uji aktivitas antioksidan dilakukan menggunakan metode 1,1-difenil-2-pikrilhidrazil (DPPH) dengan memvariasikan konsentrasi larutan uji, yaitu 5; 15; 25 ppm. Hasil dari penelitian ini melaporkan astaxanthin pada ekstrak cincalok menunjukkan nilai Rf 0,32 pada kromatografi lapis tipis (KLT). Hasil analisis menggunakan spektrofotometer UV-Vis menghasilkan spektra dengan panjang gelombang maksimum 477 nm, yang sesuai dengan panjang gelombang maksimum astaxanthin standar. Randemen ekstrak astaxanthin dari cincalok pada penelitian ini adalah 1,47 mg/100 g berat basah. Kromatogram dari hasil analisis UHPLC menunjukkan waktu retensi ekstrak astaxanthin cincalok yaitu selama 6,27 menit dengan kemurnian sebesar 18,03%. Aktivitas antioksidan dari ekstrak astaxanthin cincalok diperoleh sebesar 568,32 ppm.
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Alarcón Hernández, Fidel Benjamín, María del Carmen Fuentes Albarrán, José Luis Gadea Pacheco, Ángel Tlatelpa Becerro, and Víctor Aristeo Cañete Cabrera. "Evaluation of the Degradation Process of Diethyl (3H-1-Ethoxy-3-phenoxazinylidene) Ammonium Chloride in Water, after Exposure to Nonthermal Plasma at Atmospheric Pressure." Journal of Chemistry 2022 (June 13, 2022): 1–8. http://dx.doi.org/10.1155/2022/4486227.
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The present study characterizes the degradation of diethyl dye (3H-1-ethoxy-3-phenoxazinylidene) ammonium chloride in water (concentration of 20.00 mg/L), after its exposure to nonthermal plasma of air at atmospheric pressure. The exposure time of the solution of interest to the plasma was 250 minutes per treatment. Four different nonthermal plasma generation conditions were considered (15, 20, 25, and 30 mA) at a voltage of 2000 V. The change in dilution was determined by UV/VIS spectrophotometry (absorbance and concentration), chemical oxygen demand (COD), pH, and bioassays with lettuce seeds (Lactuca sativa). Given the increase in temperature of the sample under study due to exposure to plasma, the change in each of the measured parameters was also explored as an exclusive function of the increase in temperature (27°C to 44°C). The measurements did not show the influence of temperature on the changes observed in the parameters of interest in this experiment. In general, the maximum degradation obtained from the samples analyzed at the end of the treatments corresponds to the 30 mA treatment. For this, reductions of 70.4% in absorbance, 71.5% of dye concentration, 81.6% of COD, and 51.85% of pH were achieved. The germination percentage of the lettuce seeds obtained was 74%. The degradation of the dye in the solution of interest depends on the plasma generating parameters high power and the high degradation rate.
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Dimiņš, Fredijs, Velga Miķelsone, and Miķelis Kaņeps. "Antioxidant Characteristics of Latvian Herbal Tea Types." Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences 67, no. 4-5 (November 1, 2013): 433–36. http://dx.doi.org/10.2478/prolas-2013-0067.
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Abstract The aim of the study was to characterise antioxidative properties and antiradical activity of the herbal tea collection in Latvia. High-pressure liquid chromatography and spectrophotometry methods were used to characterise antioxidant properties of herbal tea. Antiradical activity was determined spectrophotometrically. The antiradical scavenging activity was measured by the DPPH (2,2-diphenyl-1-picrylhydrazyl) reaction. The herbal tea antiradical scavenging activity was estimated as the broken down quantity of DPPH on 100 grams of the herbal tea. Individual polyphenols in the herbal tea were identified and determined by liquid chromatography. Antiradical scavenging activity of the herbal tea was found to be 104 mol 100 g-1 tea. The following polyphenols were identified chromatographically in herbal tea: gallic, caffeic, chlorogenic, ferulic acids, rutin, catechin, vanillin, and epicatechin. Altogether 12 different varieties of herbal tea samples were analyzed. The results showed that different types of herbal tea substantially differed in composition. Polyphenol content of herbal teas was in the range of 1 mg in 100 g of tea up to 8 g per 100 g of tea. In the case of virus-related disease, infections and weakness of the organism, it is recommended to use tea with high content of rutin, as in Verbascum thapsiforme Schr., Alchemilla vulgaris L., Comarum palustre L. herbal tea.
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Nucuhay, Peerapong, Chinoros Laongwan, Wimol Promcham, Saksorn Limwichean, and Mati Horprathum. "Effect of controlled operating pressure on physical optical and electrical properties of AZO thin film by DC magnetron sputtering technique." Journal of Materials Science and Applied Energy 11, no. 3 (August 31, 2022): 244616. http://dx.doi.org/10.55674/jmsae.v11i3.244616.
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The study aimed to research the controlled operating pressure in the range of 1.10 × 10–2 − 2.60 × 10–3 mbar with the adjustment position of plate valve (40 – 100%) using DC pulsed magnetron sputtering system. The AZO films were prepared onto n-type silicon (100) and glass slide substrates. A comparison, all samples were assigned 400 nm of AZO film thickness and then the prepared AZO films were investigated by field-emission scanning electron microscope (FE-SEM) for surface morphologies, X-ray diffraction (XRD) for crystallinity, UV-Vis-NIR spectrophotometry for optical property, Four-point probe and Hall effect instrument for electrical properties, respectively. The results from FE-SEM image showed that the AZO film was columnar structure. The XRD patterns of AZO films demonstrated the crystal growth direction which preferred AZO growth was indicated the (polycrystalline) hexagonal wurtzite structure. For the optical property, the transmittance (%T) clearly showed transparent film, indicating good average value which was 81.54 – 83.28% in visible region (380 to 780 nm of wavelength). Furthermore, the sheet resistivity, high mobility and carrier concentration displayed 91.48 Ohm sq−1, 3.40 cm2 Vs–1 and 7.00 × 1020 cm–3, respectively. These results were decided that the position of plate valve of 85% with operating pressure of 2.70 × 10–3 mbar was the optimal condition. Finally, the excellent electrical and good optical properties of AZO film is mainly applied in several application for optoelectronic device and solar cell.
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Parker, Mark, and R. Kenneth Marcus. "Investigation of Sample Atomization Using a Power-Modulated Radio-Frequency Glow Discharge Source." Applied Spectroscopy 50, no. 3 (March 1996): 366–76. http://dx.doi.org/10.1366/0003702963906276.
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A power-modulated (pulsed), radio-frequency glow discharge source by atomic absorption spectrophotometry (rf-GD-AAS) atomizer was used to evaluate the roles of applied power, pressure, orifice diameter, duty cycle, and power-on time in the production of gas-phase sample atoms. As expected, the response of the modulated rf-GD-AAS source generally followed the same trends as those exhibited by the more common continuous-powering scheme. The effects of discharge power and pressure on the observed plasma emission and absorbance transients are presented. Use of small duty cycles and higher instantaneous powers, thus keeping the same overall average power as in the continuous mode, was shown to increase the production of ground-state atoms. However, using very high instantaneous powers may more efficiently populate excited states of the atomic species, thus decreasing the observed absorption signal for resonant transitions. Individual pulse transients were shown to be distorted if the plasma “on” times approached periods down to 2 ms. Plasma stabilization times for measurements taken in the “dark” portion of the pulse cycle (i.e., after pulse termination) were comparable to those obtained in the continuous mode (on the order of a few seconds) with the use of the same source and sample. Calibration curves were used to investigate the analytical utility of different temporal regions of the absorption transients with comparisons made between the plasma “on” and “off” portions of the cycle in the quantification of continuous plasma operation.
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Ott, P. "Plasma elimination of indocyanine green in the intact pig after bolus injection and during constant infusion: Comparison of spectrophotometry and high-pressure liquid chromatography for concentration analysis,." Hepatology 18, no. 6 (December 1993): 1504–15. http://dx.doi.org/10.1016/0270-9139(93)90245-i.
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