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The current study attempts to evaluate the formation, morphology, and physico-chemical properties of zinc oxide nanoparticles (ZnO NPs) synthesized from Clinopodium vulgare extract at different pH values and to investigate their antimicrobial and biomedical application potential. The reduction of zinc ions to ZnO NPs was determined by UV spectra, which revealed absorption peaks at 390 nm at pH 5 and 348 nm at pH 9, respectively. The spherical morphology of the nanoparticles was observed using scanning electron microscopy (SEM), and the size was 47 nm for pH 5 and 45 nm for pH 9. Fourier-transformed infrared spectroscopy (FTIR) was used to reveal the presence of functional groups on the surface of nanoparticles. The antibacterial activity was examined against Staphylococcus aureus, Streptococcus pyogenes, and Klebsiella pneumonia via the agar-well diffusion method. Comparatively, the highest activities were recorded at pH 9 against all bacterial strains, and among these, biogenic ZnO NPs displayed the maximum inhibition zone (i.e., 20.88 ± 0.79 mm) against S. aureus. ZnO NPs prepared at pH 9 exhibited the highest antifungal activity of 80% at 25 mg/mL and antileishmanial activity of 82% at 400 mg/mL. Altogether, ZnO NPs synthesized at pH 9 show promising antimicrobial potential and could be used for biomedical applications.

Occurrence of cyanobacterial blooms in source waters challenges water treatment processes. During a successive bloom, typical characteristics of elevated cell-density and pH were observed from development to maintenance stage. However, studies about their influences on the coagulation process have been limited. Here, PACl coagulation experiments were conducted to investigate Microcystis removal with varied pH and cell-density. Results showed that PACl coagulation alone was sufficient to remove Microcystis with low cell-density (105–106 cells mL−1), since an elevated pH value (8.5–9.5) can promote PACl coagulation, possibly ascribed to sweeping cells via neutral gelatinous precipitate of alum. Nevertheless, elevated cyanobacterial biomass was a striking factor in decreasing Microcystis removal (80%–100%) by PACl coagulation, since its inhibitory effects on the coagulation process could not be offset by in situ elevated pH value. Chlorination-assisted (1 mg L−1) coagulation was recommended to treat cyanobacteria-laden source waters with high cell-density of >107 cells mL−1, as it promoted cyanobacterial removal and achieved the highest removal ratio of DOC and turbidity among these treatments. These findings will provide an important reference for water supplies to choose the proper water treatment process to treat cyanobacteria-laden source waters during a successive bloom. HIGHLIGHTS Elevated pH (8.5–9.5) enhanced cyanobacterial removal by PACl coagulation.; Elevated cell-density (107 cells mL−1) hindered cyanobacterial removal by PACl coagulation.; Coagulation alone was sufficient to remove cyanobacteria of 105–106 cells mL−1.; Pre-chlorination was necessary to treat elevated cyanobacterial biomass of 107 cells mL−1.

The purpose of the work is to check samples of cosmetic face or hand creams for compliance with the requirements of technical documents declared by manufacturers.

The mycelium-free supernatant (MFS) of a five-day-old culture medium of Fusarium oxysporum was used to synthesize gold nanoparticles (AuNPs). The experimental design of the study was to answer the question: can this production process of AuNPs be controllable like classical chemical or physical approaches? The process of producing AuNPs from 1 mM tetrachloroauric (III) acid trihydrate in MFS was monitored visually by color change at different pH values and quantified spectroscopically. The produced AuNPs were analyzed by transmission electron microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The presence of capping agents was confirmed by Fourier transform infrared spectroscopy (FTIR). Two AuNP samples with acidic and alkaline pH were selected and adjusted with the pH gradient and analyzed. Finally, the size and zeta potential of all samples were determined. The results confirmed the presence of the proteins as capping agents on the surface of the AuNPs and confirmed the production of AuNPs at all pH values. All AuNP samples exhibited negative zeta potential, and this potential was higher at natural to alkaline pH values. The size distribution analysis showed that the size of AuNPs produced at alkaline pH was smaller than that at acidic pH. Since all samples had negative charge, we suspect that there were other molecules besides proteins that acted as capping agents on the surface of the AuNPs. We conclude that although the biological method of nanoparticle production is safe, green, and inexpensive, the ability to manipulate the nanoparticles to obtain both positive and negative charges is limited, curtailing their application in the medical field.

The aim of the present research work is experimental investigation to evaluate various physical, Mechanical and Corrosion Test Properties and concentrates on the progress of biomaterials in the field of orthopedics especially for Tibia bone an effort to utilize the 10% JPCM(S1), 10% EPCM(S2) and 10% CPCM(S3), and fabricated the bio composites materials. The present invention focuses on the enhanced properties of 10% JPCM(S1), 10% EPCM(S2) and 10% CPCM(S3) as Tibia bone implant material. It is a challenge to the creation of better materials for the improvement of quality of life and Economical one suggests to use Tibia Bone Prosthesis (Rods, Plates etc.,) and also Characterization is carried out using Epoxy resin -LY556 as a matrix material and hardener -HY 951 with 10% Carbon fiber, E-Glass fiber and Jute fiber reinforced composite material with 0+/-90 Degree orientation. by using hand layup fabrication technique the specimens are prepared as per biomaterials ASTM standards for Tensile Tests specimens are prepared by ASTM D-3039, For Compression Tests specimens are prepared by ASTM D-3410 and for Bending Tests specimens are prepared by ASTM D-790 , Wear by G-99, Fatigue test was conducted i.e. ASTM D3479 / D3479M - 19 and ASTM D- 3039 Standard also Moisture ,Impact and Corrosion test was also carried out according to ISO standard for the same specimen to know the biocompatibility.

The aim of the present research work is experimental investigation to evaluate various physical, Mechanical and Corrosion Test Properties and concentrates on the progress of biomaterials in the field of orthopedics especially for Tibia bone an effort to utilize the 10% JPCM(S1), 10% EPCM(S2) and 10% CPCM(S3), and fabricated the bio composites materials. The present invention focuses on the enhanced properties of 10% JPCM(S1), 10% EPCM(S2) and 10% CPCM(S3) as Tibia bone implant material. It is a challenge to the creation of better materials for the improvement of quality of life and Economical one suggests to use Tibia Bone Prosthesis (Rods, Plates etc.,) and also Characterization is carried out using Epoxy resin -LY556 as a matrix material and hardener -HY 951 with 10% Carbon fiber, E-Glass fiber and Jute fiber reinforced composite material with 0+/-90 Degree orientation. by using hand layup fabrication technique the specimens are prepared as per biomaterials ASTM standards for Tensile Tests specimens are prepared by ASTM D-3039, For Compression Tests specimens are prepared by ASTM D-3410 and for Bending Tests specimens are prepared by ASTM D-790 , Wear by G-99, Fatigue test was conducted i.e. ASTM D3479 / D3479M - 19 and ASTM D- 3039 Standard also Moisture ,Impact and Corrosion test was also carried out according to ISO standard for the same specimen to know the biocompatibility.

Our aim was to assess the blood physiology and antioxidant and immune responses of the olive flounder (Paralichthys olivaceus) following pH changes in the water. P. olivaceus (mean weight 95.7 ± 6.5 g and mean length 21.4 ± 1.3 cm) were exposed to the different pH levels (pH 5, 6, 7, 8, 9, and 10) for 2 weeks. Blood physiology parameters, such as the levels of hematocrit, magnesium, glucose, glutamic oxalate transaminase (GOT), glutamic pyruvate transaminase (GPT), and alkaline phosphatase (ALP) were significantly altered by low (acidic) pH or high (alkaline) pHs. With regard to antioxidant responses, the superoxide dismutase (SOD) and glutathione S-transferase (GST) activities in the liver were significantly altered by the pH changes, but there were no significant changes of these activities in the gill tissues. The immunoglobulin M levels increased significantly at pH 10 after 2 weeks. The results of this study suggest that pH changes (acidity: < pH 6, alkalinity:> pH 9) affect blood physiology, as well as antioxidant and immune responses in P. olivaceus.

The digestive system of the chicken plays an important role in metabolism, immunity, and chicken health and production performance. The chicken ceca harbor a diverse microbial community and play a crucial role in the microbial fermentation and production of energy-rich short-chain fatty acids (SCFA). For humans, dogs, and piglets in vitro digestive system models have been developed and are used to study the microbiota composition and metabolism after intervention studies. For chickens, most research on the cecal microbiota has been performed in in vivo experiments or in static in vitro models that may not accurately resemble the in vivo situations. This paper introduces an optimized digestive system model that simulates the conditions in the ceca of the chicken, i.e., the Chicken ALIMEntary tRact mOdel-2 (CALIMERO-2). The system is based on the well-validated TNO in vitro model of the colon-2 (TIM-2) and is the first dynamic in vitro digestion model for chickens species. To validate this model, the pH, temperature, and different types of microbial feeding were compared and analyzed, to best mimic the conditions in the chicken ceca. The bacterial composition, as well as the metabolite production at 72 h, showed no significant difference between the different microbial feedings. Moreover, we compared the CALIMERO-2 digestive samples to the original inoculum and found some significant shifts in bacterial composition after the fermentation started. Over time the bacterial diversity increased and became more similar to the original inoculum. We can conclude that CALIMERO-2 is reproducible and can be used as a digestive system model for the chicken ceca, in which the microbial composition and activity can be maintained and shows similar results to the in vivo cecum. CALIMERO-2 can be used to study effects on composition and activity of the chicken cecum microbiota in response to in-feed interventions.

Hot dip galvanizing technology is now widely used as a method of protection for steel rebars. The corrosion behaviors of Q235 carbon steel and hot galvanized steel in a Ca(OH)2 solution with a pH from 10 to 13 was investigated by electrode potential and polarization curves testing. The results indicated that carbon steel and hot galvanized steel were all passivated in a strong alkaline solution. The electrode potential of hot dip galvanized steel was lower than that of carbon steel; thus, hot dip galvanized steel can provide very good anodic protection for carbon steel. However, when the pH value reached 12.5, a polarity reversal occurred under the condition of a certain potential. Hot dip galvanized coating became a cathode, and the corrosion of carbon steel accelerated. The electrochemical behaviors and passivation abilities of hot dip galvanized steel and carbon steel were affected by pH. The higher the pH value was, the more easily they were passivated.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16675

In this study, experiments were designed to reveal in-depth information of the effect of pH and hydraulic retention time (HRT) on biohydrogen fermentation from liquid swine manure supplemented with glucose using an Anaerobic Sequencing Batch Reactor (ASBR) System. Five values of HRT (8, 12, 16, 20, and 24 h) were first tested and the best HRT determined was further studied at five pH levels (4.4, 4.7, 5.0, 5.3, and 5.6). The results showed that for HRT 24 h, there was a dividing H 2 content (around 37%) related to the total biogas production rate for the ASBR System running at pH 5.0. When the H 2 content went beyond 37%, an appreciable decline in biogas production rate was observed, implying that there might exist an H 2 content limit in the biogas. For other HRTs (8 through 20 h), an average H 2 content of 42% could be achieved. In the second experiment (HRT 12 h), the highest H 2 content (35%) in the biogas was found to be associated with pH 5.0. The upswing of pH from 5.0 to 5.6 had a significantly more impact on biogas H 2 content than the downswing of pH from 5.0 to 4.3. The results also indicated good linear relationships of biogas and H 2 production rates with HRT ( r =0.9971 and 0.9967, respectively). Since the optimal ASBR operating conditions were different for the biogas/H 2 production rates and the H 2 yield, a compromised combination of the running parameters was determined to be HRT 12 h and pH 5.0 in order to achieve good biogas/H 2 productions.

The proton transfer mechanism on the carbon cathode surface has been considered as an effective way to boost the electrochemical performance of Zn-ion hybrid supercapacitors (SCs) with both ionic liquid and organic electrolytes. However, cheaper, potentially safer, and more environmental friendly supercapacitor can be achieved by using aqueous electrolyte. Herein, we introduce the proton transfer mechanism into a Zn-ion hybrid supercapacitor with the ZnSO4 aqueous electrolyte and functionalized activated carbon cathode materials (FACs). We reveal both experimentally and theoretically an enhanced performance by controlling the micropores structure and hydrogen-containing functional groups (&ndash, OH and &ndash, NH functions) of the activated carbon materials. The Zn-ion SCs with FACs exhibit a high capacitance of 435 F g&minus, 1 and good stability with 89% capacity retention over 10,000 cycles. Moreover, the proton transfer effect can be further enhanced by introducing extra hydrogen ions in the electrolyte with low pH value. The highest capacitance of 544 F g&minus, 1 is obtained at pH = 3. The proton transfer process tends to take place preferentially on the hydroxyl-groups based on the density functional theory (DFT) calculation. The results would help to develop carbon materials for cheaper and safer Zn-ion hybrid SCs with higher energy.

The article deals with two wells in the country of Brno-district (Brčálka well and Well Olšová). The aim of work was monitoring of elementary parameters of water at regular monthly intervals to measure: water temperature, pH values, solubility oxygen and spring yield. According to the client's requirements (Lesy města Brno) laboratory analyzes of selected parameters were done twice a year and their results were compared with Ministry of Health Decree no. 252/2004 Coll.. These parameters: nitrate, chemical oxygen demand (COD), calcium and magnesium and its values are presented in graphs, for ammonium ions and nitrite in the table. Graphical interpretation of spring yields dependence on the monthly total rainfall and dependence of water temperature on ambient temperature was utilized. The most important features of wells include a water source, a landmark in the landscape, aesthetic element or resting and relaxing place. Maintaining wells is important in terms of future generations.

Using targeted genetical genomics, a quantitative trait locus (QTL) affecting the initial postmortem pH value of chicken breast muscle (Pectoralis major) on chromosome 1 (GGA1) recently was fine-mapped. Thirteen genes were present in the QTL region of approximately 1 Mb. In this study, 10 birds that were inferred to be homozygous for either the high (QQ) or low (qq) QTL allele were selected for resequencing. After enrichment for 1 Mb around the QTL region, >500 × coverage for the QTL region in each of the 10 birds was obtained. In total 5056 single-nucleotide polymorphisms (SNPs) were identified for which the genotypes were consistent with one of the QTL genotypes. We used custom tools to identify putative causal mutations in the mapped QTL region from these SNPs. Four nonsynonymous SNPs differentiating the two QTL genotype groups were identified within four local genes (PRDX4, EIF2S3, PCYT1B, and E1BTD2). Although these are likely candidate SNPs to explain the QTL effect, 54 additional consensus SNPs were detected within gene-related regions (untranslated regions, splicing sites CpG island, and promoter regions) for the QQ birds and 71 for the qq birds. These could also play a role explaining the observed QTL effect. The results provide an important step for prioritizing among a large amount of candidate mutations and significantly contribute to the understanding of the genetic mechanisms affecting the initial postmortem pH value of chicken muscle.

Gamma-Aminobutyric acid (GABA) could regulate physiological functions in the gastrointestinal tract. The present study aimed to investigate the effect of GABA on colon health in mice. The female Kunming mice were given GABA at doses of 5, 10, 20 and 40 mg/kg/d for 14 days. Afterwards, the short-chain fatty acids (SCFAs) concentrations, pH values, colon index, colon length and weight of colonic and cecal contents were determined to evaluate the effects of GABA on colon health. The results showed that intake of GABA could increase the concentrations of acetate, propionate, butyrate and total SCFAs in colonic and cecal contents, as well as the weight of colonic and cecal contents. The colon index and length of the 40 mg/kg/d GABA-treated group were significantly higher than those of the control group (p < 0.05). In addition, decrease of pH values in colonic and cecal contents was also observed. These results suggest that GABA may improve colon health.

International audience; Calcium carbonate (CaCO3) precipitation in tunnel drainage system poses serious problems to railway tracks. In this study, the calcification phenomenon identified in Meyssiez tunnel was analyzed through laboratory testing and site water monitoring. In particular, the surrounding soils were investigated in the laboratory. Site water table was regularly monitored in the field and site water was taken for laboratory analyses in terms of pH and electrical conductivity (EC). Examination of the test results showed that the calcification phenomenon was mainly induced by the calcium carbonate dissolution in the fine fractions (d

Carbon xerogels (CXs) synthesized from resorcinol and formaldehyde under different pH conditions were investigated. Both the textural and surface properties of the CXs depend closely on the pH used in the synthesis procedure. Concerning the texture, the mesoporous surface area (Smeso) increases and the micropore volume (Vmicro) decreases as the pH increases; concerning the surface chemistry, surface oxygen functional groups were easier to be created (by O2) on CX synthesized at lower pH. Application of these CXs as support of gold catalysts was also studied. Results showed that the oxygen activated CX that was synthesized at moderate pH (i.e., pH 6.0) was the most favorable support for gold catalysts used in selective oxidation of benzyl alcohol by molecular oxygen in liquid phase, due to the adequate amounts of surface oxygen functional groups created on the surface.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:07:56Z No. of bitstreams: 1 S1516-35982012000700032.pdf: 49701 bytes, checksum: 2ada2a4be8dcdde3d2f7e1c6a23c5a29 (MD5) Made available in DSpace on 2013-08-22T19:07:56Z (GMT). No. of bitstreams: 1 S1516-35982012000700032.pdf: 49701 bytes, checksum: 2ada2a4be8dcdde3d2f7e1c6a23c5a29 (MD5) Previous issue date: 2012-07-01 Made available in DSpace on 2013-09-30T20:12:44Z (GMT). No. of bitstreams: 2 S1516-35982012000700032.pdf: 49701 bytes, checksum: 2ada2a4be8dcdde3d2f7e1c6a23c5a29 (MD5) S1516-35982012000700032.pdf.txt: 27863 bytes, checksum: 25a397bb8f488e8746baefff3f4a30ce (MD5) Previous issue date: 2012-07-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:18:13Z No. of bitstreams: 2 S1516-35982012000700032.pdf: 49701 bytes, checksum: 2ada2a4be8dcdde3d2f7e1c6a23c5a29 (MD5) S1516-35982012000700032.pdf.txt: 27863 bytes, checksum: 25a397bb8f488e8746baefff3f4a30ce (MD5) Made available in DSpace on 2014-05-20T13:18:13Z (GMT). No. of bitstreams: 2 S1516-35982012000700032.pdf: 49701 bytes, checksum: 2ada2a4be8dcdde3d2f7e1c6a23c5a29 (MD5) S1516-35982012000700032.pdf.txt: 27863 bytes, checksum: 25a397bb8f488e8746baefff3f4a30ce (MD5) Previous issue date: 2012-07-01 The characteristics of fermentation and aerobic stability were evaluated in corn silage inoculated with different doses of Lactobacillus buchneri. The whole corn plant (300 g/kg DM) was ensiled in quadruplicate laboratory silos (7L). L. buchneri 40788 was applied at 5×10(4), 1×10(5), 5×10(5) and 1×10(6) cfu/g of fresh forage. Silages with no additive were used as controls. After 130 d of ensiling, the silages were subjected to an aerobic stability evaluation for 12 days, in which chemical and microbiological parameters as well as the temperature of the silage were measured to determine the aerobic deterioration. The addition of L. buchneri resulted in increased acetic acid concentrations. The number of yeast colonies was low in all treated silages. The pH, lactic and propionic acid concentrations did not differ between silages. Under aerobic conditions, all the treated silages showed a low number of yeasts and a great aerobic stability. Therefore, L. buchneri is effective against yeasts and improves the aerobic stability of corn silage in laboratory silos. However, doses equal or superior to 1×10(5) cfu/g of fresh forage were more efficient in the control of aerobic spoilage. UNESP Faculdade de Ciências Agrárias e Veterinárias Universidade Federal de Lavras (UFLA) UNESP Faculdade de Ciências Agrárias e Veterinárias

A low molecular weight hydrogelator with a covalently appended imidazole moiety is reported. Capable of percolating water in the pH range of 6 to 8, it proves to be an efficient catalyst upon self-assembly, showing Michaelis-Menten type kinetics. Activities at different pH values correlated with dramatic structural changes were observed. It can hydrolyse p-nitrophenyl acetate (pNPA) as well as inactivated esters, and L and D-phenylalanine methyl esters. The enhanced activity can be related to the conglomeration of catalytic groups upon aggregation resulting in their close proximity and the formation of hydrophobic pockets. This work was supported by the EU Marie Curie ITN-Smartnet and the Ministry of Economy and Competitiveness of Spain (Grant CTQ2012-37735). N.S. and M.P.C. thank EU for an ESR Marie Curie contract.

Bismuth molybdate single-crystallites were synthesized by a simple hydrothermal method at different pH values. The as-fabricated samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM); it has been found that the pH values of the precursors can significantly influence the structures of the products. Under the Bi/Mo ratio of 2:1 conditions (a nominal composition of Aurivillius structure), low pH leads to the formation of γ-Bi2MoO6 with Aurivillius type structure, while neutral and higher pH values lead to the formation of γ-Bi2MoO6/Bi2O3 composite, and Bi2O3, respectively. The photocatalytic activities of the samples with different structures were measured for the degradation of methylene blue (MB) under simulated sunlight irradiation. Among the as-fabricated bismuth molybdate samples, the γ-Bi2MoO6 exhibited superior photocatalytic efficiency to the γ-Bi2MoO6/Bi2O3 composite and the Bi2O3, mainly due to its unique layered Aurivillius structure, smaller band gap structures and smaller particle sizes.

The synthesis of pure and well dispersed lutetium aluminum garnet (LuAG) powder is crucial and important for the preparation of LuAG transparent ceramics. In this paper, high purity and well dispersed LuAG powders have been synthesized via co-precipitation method with lutetium nitrate and aluminum nitrate as raw materials. Ammonium hydrogen carbonate (AHC) was used as the precipitant. The influence of aging time, pH value, and dripping speed on the prepared LuAG powders were investigated. It showed that long aging duration (&gt, 15 h) with high terminal pH value (&gt, 7.80) resulted in segregation of rhombus Lu precipitate and Al precipitate. By decreasing the initial pH value or accelerating the dripping speed, rhombus Lu precipitate was eliminated and pure LuAG nano powders were synthesized. High quality LuAG transparent ceramics with transmission &gt, 75% at 1064 nm were fabricated using these well dispersed nano LuAG powders.

High-powered means of slaughter chickens production cause on certain individuals abnormal biochemical development of postmortal changes in their muscles. It consequently lead to interferences of sensory quality of the chicken meat. So called myopathies of the chicken breast meat occur in the low extent. It is typical variation in dark colouring of breast muscle. Veterinary supervision confiscates chickens embodying myopathy by reason of sensorical unacceptable dark muscle colour. Deepness of colour is evaluated by adspection of veterinary supervisors. It is tendency leading to find out objective parameters for evaluating this sensual chicken meat colour variation. Incidence of the chickens with myopathy has been evaluating for 3 years in big poultry slaughter, therewithal high-quality chickens and chickens with perspicuous myopathy have been taking out of slaughter-line. Electric conductivity values and pH values were measuring during 60 till 330 minutes post mortem in breast muscles. Aproximately 9 millions chicken was annually slaughtered and 13 thousands of them was confiscated out of the slaughter line by reason of myopathy. It amounts to 0.14 per cent of annually count of processed chickens. Myopatical chickens had significantly higher muscle pH values as compared with healthy ones. Healthy chicken muscles decreased on ultimative pH values aproximately past 3 hours post mortem. It means pH 6.03, and after 300 minutes decreased to pH 5.82. However, myopatical chickens values varied from pH 6.46 to pH 6.30. Concurrently measured values of electric conductivity significantly corellated with pH values. Whereto, it's predication of similarity chicken myopathies and dark, firm, dry (DFD) pork or turkey meat. Beyond unacceptable dark meat colour have disadvantage in poor post mortem acidifying of the meat and in consequence of microbial proteolyse. Significantly correlation between pH and electric conductivity values foreshadows on identification of myopatical chicken meat by means of conductivity measuring.

The objective of this study was to investigate the joint effects of the temperature, carbohydrate concentration, and pH value of the nutrient medium on the initial and final growth of the mycelium of two Pleurotus ostreatus strains. The experiment was carried out at the Institute of Field and Vegetable Crops in Novi Sad. The strains were grown in five climatic chambers, each with a different temperature (15 degreesC, 20 degreesC, 25 degreesC, 30 degreesC, and 35 degreesC). Three different concentrations of carbohydrates (0.1%, 0.2% and 0.3%) and two pH values (5.0 and 6.0) of the medium were used to grow the mycelium and three replicates. It was concluded that the optimum mycelium growth of the two strains requires different conditions for initial growth in relation to the final growth, with respect to temperature, pH level and sugar concentration in the nutrient medium. The optimum relationship between nutrient medium and temperature was found to be strain-specific.

The use of metals and alloys in dentistry has seen remarkable progress due to the deep research on their biocompatibility or the application of advanced technologies to improve surface properties by controlling material/environment interactions occurring in the mouth. The biocompatibility of metals and alloys is a consequence of the presence of the surface oxide layer. The chemical properties and therefore the interface chemical processes are determined precisely by this oxide layer and not the metal itself. The material response to changes in pH, to the application of force or the degrading effects of fluids may impair biocompatibility. Corrosion resistance, an important feature of the biocompatibility, can be verified by studying the electrochemical behaviour of metals and alloys in specific environments. This paper presents some research results on the corrosion behaviour of Co-Cr biomaterial composition in aqueous solutions with different pH (Fusayama - Meyer artificial saliva, Hank’ s and Ringer’ s solutions, citric acid) given that many of chemical reactions in the mouth are extremely sensitive to the environmental pH. The electrochemical methods used (free potential, potentiodynamic curves and cyclic polarization) are relevant methods for studying interactions of materials - specific environment of use/exploitation. Research has shown different behaviour of the alloy according to the pH, the chloride content and the oxidizing nature of the environment.

The paper presents the results of sensory perception of saltiness of various 0.2% aqueous solutions of sodiumchloride, potassium-chloride and their mixtures, at different pH values. Water solutions were prepared with deionised water at three pH values: 4.60, 5.80 and 3.60. To identify potential differences in the salinity of different solutions, ranking test in three sets as well as triangle test in nine sets were organized with eight trained assessors . In all three sets of ranking test, five assessors (62.50%) recognized the increasing level of salinity and correctly ranked the three solutions, while three assessors (37.50%) incorrectly ranked the solutions according to the level of salinity. Completely recognizing of different samples by assessors was established in the case of solutions prepared with deionized water with initial pH values of 5.80 and 3.60, while the least level of recognizing was established in solutions prepared from water with pH value of 4.60 . According to the obtained results, it can be concluded that the highest recognition of the differences in the level of salinity was in solutions prepared with water of pH value 5.80 and 3.60 . In one solution set, at pH values close to 5.80, all of the assessors (100 %) recognized the sample solution, which was different from the other two, while in two sets different sample was recognized by seven of the eight assessors (87.50 %). Full recognition of the difference (100 %) was recorded in the set of solutions prepared with deionised water of an initial pH value of 3.60.

Dissertação de mestrado integrado em Engenharia Biológica (área de especialização em Tecnologia Química e Alimentar), A carne é um alimento com características que a tornam um meio propício à deterioração. O pH é um dos fatores que mais influencia a conservação da carne bovina, pelo facto de interferir com a capacidade de retenção de água e com o desenvolvimento microbiano nesta. Por outro lado, o pH tem um papel decisivo na qualidade exibida pela carne, pois influencia características às quais os consumidores dão elevado ênfase, como cor, textura e suculência. Uma forma de se prolongar o tempo de vida útil de carnes de bovino frescas é embalando-as a vácuo. A remoção do ar da embalagem faz com que se previna o crescimento de microrganismos que deterioram o produto, a oxidação e a descoloração da carne. O presente trabalho tinha como principais objetivos avaliar a variação do pH mediante o local de medição na carcaça e determinar quais os parâmetros que influenciam o pH post mortem. Acresce ainda, a atribuição do máximo tempo de vida útil a peças de bovino embaladas a vácuo, com pH inicial conhecido. De forma a atingir os objetivos supra mencionados procedeu-se à medição de pH, pelo método potenciométrico (método não destrutivo), em carcaças de bovino, ao nível da 5ª e da 14ª costelas no músculo Longissimus dorsi. Constatou-se que o pH da carne de bovino é mais elevado quando medido do lado esquerdo da carcaça, tanto ao nível da 5ª costela como ao nível da 14ª costela. Verificou-se ainda que a média de pH se apresentou mais elevada para bovinos do sexo feminino do que para bovinos do sexo masculino, 5,77 ± 0,03 e 5,70 ± 0,02, respetivamente. Por outro lado, apurou-se que o pH é superior em bovinos mais velhos já que a média de pH para animais entre 0-25 meses foi de 5,68 e entre 101-200 foi de 5,82. Relativamente à carne embalada a vácuo verificou-se que, de uma forma geral, o pH diminuiu ao longo do tempo de armazenamento e que esta diminuição de pH era acompanhada por um aumento do crescimento microbiano, o que leva a inferir que a diminuição de pH é resultado da produção de ácido láctico por ação das bactérias lácticas microaerófilas. Apurou-se ainda que valores de pH da carne superiores a 5,80, passadas, no mínimo, 24 horas post mortem, podem advir, por exemplo, do stresse e tempo de jejum a que os bovinos estão sujeitos, momentos antes do abate. Verificou-se que existe uma tendência de elevado crescimento microbiano em carnes DFD (“dark, firm and dry”) e que nestas há uma dificuldade acrescida em determinar o seu tempo de vida útil. Concluiu-se que existem vários fatores que influenciam o pH da carne, como: sexo e idade do animal. O lado da carcaça onde se realizam as medições de pH também interfere muito nos resultados obtidos. Na metade esquerda da carcaça é onde se observam os valores mais elevados de pH. O fator mais difícil neste trabalho foi conseguir determinar o tempo de vida útil de carne de bovino DFD pelo facto de que muitos microrganismos têm um ótimo crescimento para valores de pH próximo de 7,00. Inferiu-se ainda que a determinação do tempo de vida útil da carne de bovino embalada a vácuo não foi realizada de forma rigorosa pelo facto de, no decorrer deste estudo, se alterarem variáveis como tipo de saco utilizado na embalagem a vácuo, pressão e tempo de armazenamento. Assim, os resultados obtidos apenas se podem aplicar àquelas condições em particular, não podendo ser extrapolados para a carne bovina no geral., Meat pH is one of the factors that influence the most its preservation, once it interferes with the ability to retain water and with microbial growth. Futhermore, the pH plays a decisive role in the quality exhibited by the meat, since it influences the characteristics which consumers rate the most, such as colour, texture and juiciness. One way to extend the shelf life of fresh beef meat is to pack it in vacuum. The removal of the air from the container prevents the following aspects: the growth of microorganisms which degrade the product, oxidation and discoloration of the meat. The main objectives of this work were the evaluation of the changes in pH values depending on the measurement place, as well as the determination of which parameters influence postmortem pH values. It was also attributed the maximum shelf life for vacuum packed beef meat, knowing its initial pH value. In order to achieve the objectives referred above, pH measurements were done using potentiometric methods (nondestructive) in the 5th and in the 14th ribs of the Longissimus dorsi muscle in the bovine carcass. It was found that the pH values for bovine meat were higher when measured in the left side of the carcass for both 5th and 14th ribs. It was also observed that the average pH values were higher in female bovine meat than in male bovine meat (5,77 ± 0,03 and 5,70 ± 0,02, respectively). On the other hand, it was possible to verify that pH values are higher in the older bovine, given that the average pH values for the animals from 0 to 25 months were 5,68 and 5,82 to animals from 101 to 200 months. In what concerns to the beef meat vacuum packed, it was found that, in general, pH values decreased during storage time and that this decrease was accompanied by an increase in microbial growth. This leads to the conclusion that the decrease in pH values was due to lactic acid production by microaerophilic lactic acid bacterias. It was also possible to conclude that pH values higher than 5,80 for, at least, 24 hours postmortem can be due to factors such as stress and time of fasting animals are subjected just before slaughter. It was observed a high tendency for microbial growth in DFD meat and, therefore, there were a further difficulty to determine the shelf life in this type of meat. It was concluded that there are several factors which influence the pH values of the meat, such as the gender and the age of the animal. Besides, the side of the carcasses where the measurements took place interferes with the results obtained and it was realized that the best pH value results were observed in the left half of the carcass. The predominant and most difficult factor in this study was the determination of the shelf life of DFD meat because of the fact that many microorganisms have an optimum growth at pH values near 7,00. We can also conclude that the determination of the shelf life of vacuum-packed beef meat was not performed accurately because, during this study, there were a change in variables as the type of bag used in vacuum packing, the pressure and the storage time. Thus, the results obtained can only be applied to those particular conditions and they cannot be extrapolated for beef meat in general.

12-volframfosforna (WPA), 12-volframsilicijumova (WSiA) i 12-molibdenfosforna kiselina (MoPA) su heteropoli kiseline (HPK) koje pripadaju velikoj klasi jedinjenja koja se nazivaju polioksometalati. U osnovi struktura ovih kiselina je Keggin-ov anjon (KA) čija se hidrolitička stabilnost razlikuje od kiseline do kiseline, što je utvrđeno ULj, IC, ramanskom i 31P NMR spektroskopijom. Najmanje je stabilna MoPA, kod koje roditeljska Keggin-ova struktura u razblaženim rastvorima (2∙10-5 moldm-3) nije prisutna čak ni pri pH < 1,0, a u koncentrovanim rastvorima (5∙10-2 moldm-3) egzistira samo pri pH < 1,0. WPA je stabilnija, i kod nje je roditeljski anjon prisutan pri pH < 1,0 u razblaženim, odnosno pH < 1,5 u koncentrovanim rastvorima. Najstabilnija je WSiA, kod koje je KA prisutan u razblaženim vodenim rastvorima do pH = 8,5 odnosno do pH = 6,4 u koncentrovanim rastvorima. Korišćenje 50 % metanola kao rastvarača dovodi do stabilizacije KA u ovim kiselinama, tako da se u slučaju MoPA javlja sve do pH = 3,5 i u razblaženim i u koncentrovanim rastvorima. Za WPA u koncentrovanim rastvorima oblast pH u kojoj se javlja KA se proširuje do pH = 2,5, a u razblaženim čak i do pH = 7,0. Najstabilnija WSiA se dodatno stabiliše u prisustvu metanola, pa se KA javlja sve do pH = 11,5 u razblaženim, odnosno pH = 7,8 u koncentrovanim rastvorima. Proces dekompozicije WPA je delimično reverzibilan, a za vodene rastvore je potvrđena vremenska stabilnost u toku jedne godine. Prilikom upotrebe pufera za podešavanje pH vrednosti rastvora HPK, mora se voditi računa o mogućoj interakciji HPK sa puferom, kao što je to slučaj pri primeni TRIS pufera. Dobijeni rezultati se mogu iskoristiti za utvrđivanje oblika HPK prisutnih u različitim sistemima. U slučaju polianilin - WPA mikro/nanostruktura KA je dominantno prisutna vrsta, ali se identifikuju i male količine Dawson-ovog i monolakunarnog KA. WPA i WSiA u inkubacionom medijumu (uz prisustvo enzima Na+/K+_ATPaze i ATP), u obliku monolakunarnog KA, inhibiraju dejstvo enzima Na+/K+_ATPaze, što je od značaja za različite biohemijske procese. Heteropoly acids (HPA): 12-tungstophosphoric (WPA), 12-tungstosilicic (WSiA) and 12-molibdophosphoric acid (MoPA) belong to the polyoxometalates, the huge and important class of compounds. The main structure of those acids is Keggin anion (KA). The hydrolytic stability of KA differs between acids, and that is confirmed by UV, IR, Raman and 31P NMR spectroscopy. The less stable is MoPA, where parent Keggin structure in diluted solutions (2∙10-5 moldm-3) not exists even on pH < 1.0, while in concentrated solutions (5∙10-2 moldm-3) exists only if pH < 1.0. WPA is more stable; the parent Keggin anion is stable at pH < 1.0 in diluted, and pH < 1.5 in concentrated WPA solutions. The highest stability has WSiA, where KA remains in toto up to pH 8.5 and 6.4, in diluted and concentrated solutions, respectively. The addition of methanol to the HPA solutions (50 % (v/v)) leads to KA stabilization for the investigated acids. As the result, KA remains stable up to pH 3.5 for both diluted and concentrated MoPA solutions. In presence of methanol, WPA structure remains stable till pH 2.5 in concentrated, and even to pH 7.0 in diluted solutions. In case of WSiA, the KA structure is present up to pH 11.5 and 7.8, in diluted and concentrated solutions, respectively. The WPA decomposition process is partly reversible. Further, we confirmed the stability of the water solutions during the period of one year. In the case of buffer using, it is necessary to take into consideration the possible interactions of HPA with buffer’s components (TRIS buffer was tested as an example). The results can be used to determine the form of HPA present in different systems. In the case of polyaniline - WPA micro/nanostructures, KA is dominantly present species, while the traces of Dawson and monolacunar KA were identified by using IR spectroscopy. WPA and WSiA in the incubation medium (in the presence of commercial enzyme and its substrate-ATP) form monolacunary Keggin anion and exibit concentration-dependent inhibitory effect on the activity of Na+/K+-ATPase. This is important for different biochemical processes.

Ponencia presentada a la 51 Reunión Científica de la SEEP celebrada en la Escuela Superior de Ingenieros Agrónomos de la Universidad Pública de Navarra entre el 14 y el 18 de mayo de 2012. El objetivo del presente trabajo fue estudiar los efectos de la aplicación de purín de vacuno (PV) y PV mezclado con diferentes dosis de concha de mejillón (CM) sobre las propiedades químicas del suelo; así como en la producción y calidad forrajera de una pradera. Respecto a las parcelas que no fueron tratadas (control) la aplicación de PV mantuvo el pH del suelo pero disminuyó el porcentaje de saturación por acidez en el complejo de cambio. La incorporación de CM con el purín mejoró algunos parámetros de fertilidad del suelo: incrementó la concentración de Ca en el complejo de cambio, la capacidad de intercambio catiónica efectiva, disminuyó la saturación por acidez e incrementó el pH del suelo hasta niveles más apropiados para el desarrollo del cultivo, manteniendo la producción y calidad de forraje. Así mismo, benefició la persistencia del trébol en la pradera respecto a la aplicación de purín de vacuno sin concha. A la vista de los resultados, es recomendable la utilización de este producto en las explotaciones ganaderas, hecho que permitiría reducir costes derivados de la adquisición de otros productos encalantes. The aim of the present study was to determine the effects of cattle slurry (CS) application and CS mixed with mussel shell on soil chemical properties and also in the production and quality of a sown meadow. pH values in CS plots were similar to those found in not-treated soil while the concentration of Al in the soil cation exchangeable complex decreased. The addition of mussel shell to CS improved some of the soil fertility parameters: increased the concentration of exchangeable Ca, increased effective cation exchange capacity and decreased Al saturation. The pH values were significant higher in plots treated with mussel shell than that of CS treated soil without shell. The total production of pasture and forage quality were similar in all treated plots (CS and CS mixed with mussel shell treatments). The percentage of legume in the pasture was slight increased by the addition of mussel shell to CS. We concluded that the use of mussel shell can be recommended as livestock litter in farms and would provide an alternative to the use of lime reducing costs. Los autores agradecen la financiación recibida por la Xunta de Galicia, “Acciones de Cooperación para el Desarrollo de Nuevos Productos, Procesos y Tecnologías en el Ámbito Agroalimentario, Agrícola y Forestal”: FEADER 2009/37.

In this study, we extensively report the effect of glycine betaine during the refolding of partially folded bovine a-lactalbumin (a-LA) in presence of hexadecyl trimethyl ammonium bromide (HTAB), and Ribonuclease A (RNAse A) in presence of sodium dodecyl sulfate (SDS) by different complementary biophysical, light scattering, and microscopic techniques. Though a substantial refolding/compaction was observed in both the studied proteins, the fluorescence studies contradicted the finding obtained from circular dichroism spectroscopy (CD) in case of a-LA. CD stopped flow showed extensive presence of intermediates during the refolding of proteins which could potentially lead to aggregation. The aggregates as observed in dynamic light scattering (DLS), in a-LA were massive as compared to RNAse A and was directly proportional to betaine concentration. The zeta potential confirmed that the aggregates are a direct manifestation of strong aggregating and/or immense preferential excluding tendency of GB and not because of charge neutralization; however a possible role of conformational change as observed in FTIR spectroscopy cannot be completely ruled out. In contrary though RNAse A showed a substantial refolding, the final state of the folded protein was significantly different from the native state. These findings for a-LA and RNAse A were further supported by electron microscopic and thermodynamic studies. We thus propose that betaine has a strong macromolecular excluding tendency, primarily directed to shield the hydrophobic exposure either by refolding or aggregation, and depending on the hydrophobicity of the proteins, the functional restoration of the protein is manifested. (c) 2012 Wiley Periodicals, Inc. Biopolymers 97:933949, 2012.

Determination and control of the parameters influencing three-phase contact formation and wetting film stability under dynamic conditions is important for both industrial applications and fundamental studies. Hydrophobicity profoundly affects not only the critical thickness of rupture but also the subsequent rate of the three-phase contact expansion. On the other hand, surface charge has a significant impact on the wetting film stability. In the present study, by comparing collision of air bubbles of different sizes with hydrophobized amorphous titanium dioxide (TiO2) surfaces immersed into solutions at different pH values, we demonstrated that for an intermediate degree of hydrophobicity (advancing contact angle ≤ 60°), the surface charge becomes a decisive factor determining the time of the three-phase contact formation, tTPC, and the time of wetting film drainage, td. For pH values below the isoelectric point (IEP) of TiO2, the tTPC and td were significantly shorter than for pH values above the IEP. Moreover, the tTPC and td values decreased with the bubble diameter. Refereed/Peer-reviewed

CPRM O Rio Meia Ponte, principal curso d’água que atravessa a região metropolitana de Goiânia, é fortemente degradado em conseqüência da intensa urbanização da região, que vem ocorrendo desde a transferência da capital goiana de município. Esse estudo teve por objetivo analisar a qualidade das águas em oito pontos ao longo do rio no que diz respeito aos critérios ambientais. As avaliações das condições do rio se deram tanto pelo critério do Índice de Qualidade de Água (IQA) da National Sanitation Foudation (NSF) dos EUA quanto pelos padrões exigidos pela resolução CONAMA 357 de 2005 para as águas de classe dois. Dois períodos distintos foram comparados: o mês de novembro representando o chuvoso e o mês de junho representando o seco. Os padrões de qualidade da água foram levemente superiores no período seco em relação ao período úmido. Identificou-se queda nos padrões de qualidade do Rio Meia Ponte ao longo do trecho analisado, sendo essa queda mais intensa quando atravessa a região metropolitana de Goiânia. Esse estudo deixa evidente que a ocupação de uma bacia sem critérios ambientais pode comprometer consideravelmente a qualidade das águas superficiais.

La condición PSE (pálida, suave y exudativa) altera el color, la textura y el sabor de la carne, acidificándola y ocasionándole baja retención de agua, menor valor nutricional y rechazo por el consumidor. Para determinar la presencia de la característica PSE se hace medición de pH a 45 minutos (pH45) y a 24 horas post-mortem (pH24), en 520 canales de cerdo. Los valores medios de pH45 indican que el 33.65% de las canales son PSE, el 47.12% es carne normal y el 19.23% se clasifica como DFD (oscura, firme y seca). El pH24 indica aumento de PSE llegando al 68% de las canales, mientras que los porcentajes de carne normal (31.23%) y DFD (0.77%) disminuyen. Al comparar el cambio de los estados de la carne entre 45 minutos y 24 horas, el 62.44% de la carne normal pasa a ser PSE, el 87% de carne DFD pasa a ser PSE, y el 94.85% de carne PSE continua igual. Las canales presentan alta incidencia de la condición PSE tanto a 45 minutos, como a 24 horas, indicando problemas antes y después del sacrificio. Existe diferencia altamente significativa (P < 0.01) para los tres estados de la carne evaluados entre las mediciones de pH45 y pH24. The PSE (pale, soft and exudative) meat condition alters the color, the texture and the flavor of pork, increasing its acidity and occasioning low water retention, low nutritional level and rejection by the consumer. To determine the presence of the PSE characteristic, the pork carcasses are evaluated by pH measurements at 45 minutes (pH45) and 24 hours (pH24 after the slaughter of the pigs. The mean pH45 values indicate that 33.65% of the carcasses present the PSE condition, 47.12% are Normal and 19.23 % can be described as DFD (dark, firm and dry). The pH24 values indicate an increase in the PSE carcasses up to 68% while the normal and DFD ones decrease to 31.23 % and 0.77%, respectively. Comparing the change of the meat characteristics from 45 min to 24 hours, after the pig slaughter , it is observed that 62.44% of the normal meat and 87% of DFD one become PSE meat and 94.85% of the initial PSE one does not suffer any transformation. The pork carcasses present high incidence of the PSE characteristics at 45 minutes as well as 24 hours, indicating that there is problems before and after the slaughter of the pigs. High statistically significant difference (P < 0.01) is found for the three meat conditions evaluated at pH45 and pH24.

Sourdough is a semi-product which has been usually used as a starter during fermentation of bread dough. The aim of this study was to determine the influence of three parameters of sourdough fermentation (temperature, water content and type of flour) on the rate of pH value during fermentation of bread dough. Twelve fermentations of sourdough were conducted according to the following experimental design: at three fermentation temperatures (25, 30 and 35 °C), two types of flour (T-400 and T-1100) and two different water contents in THE mixture were used. Each prepared sourdough was added to the mixture for bread dough preparation. Different rates of change in pH per minute (RCpH) for all analyzed samples were determined. The obtained results showed that all of three parameters of sourdough preparation influenced RH during fermentation of bread dough. However, the highest influence on RCpH during fermentation of bread dough had incubation temperature.

Nanocomposites which consist of polymer matrix and nanoparticles of noble metal are a very important class of nanomaterials. The optical properties of these materials are strongly dependent on the nanoparticles size as well as on the synthesized procedure of nanocomposites preparation. In this work the Au nanoparticles were synthesized by the simple radiolytic procedure, using steady state gamma irradiation, under different pH values. PVA/Au nanocomposite films were obtained by solvent evaporation from Au colloids. UV-Vis absorption spectra of Au colloids show absorption in the range of 450 to 650 nm with the maximum around 520 nm, which is the typical plasmon band of Au nanoparticles. Absorption spectra of PVA/Au nanocomposites are red shifted compared to corresponding primary Au colloids. This red shift is not result of any change in particle size distribution and can be explained by the change of dielectric property of surrounding medium. IR spectra indicated anchoring the OH groups of PVA molecule at the cluster surface. This effect limits the growing of the metal clusters and confirmed that the PVA is a god matrix for in situ synthesis of Au nanoparticles. The size of Au nanoparticles is dependent on the experimental conditions. Obtained results indicated that the pH value of solution played an important role. The values of absorption maximum were not dependent on the concentration of Au3+ cations, but show strong dependence on the pH value of the initial solution. The increase of pH value reduced the mean diameters of nanoparticles. The lowest value of lambda(max) was obtained for colloid with pH 7, which theoretically corresponds to the nanoparticles with minimum dimension. These results are in agreement with the XRD measurement of PVA/Au nanocomposite films and theoretical calculations. According to obtained results of radiolytic synthesis of Au nanoparticles in PVA solution can be conclude that it is possible to control the particle size by tuning the pH value of solution. 6th Conference of Young Researchers, Dec 24-26, 2007, Belgrade, Serbia

Legionellaceae familly includes 50 strain, and more than 70 serogroups of Legionella. Natural habit of this bacteria are water and moist soil where these bacteria lives in biofilms like the parasites of protozoi. In contrast to most Legionella strain which lives in water environments, L. longbeachae is isolated from poting soil and compost. In this work we explore how different pH values affects survival of L. longbeachae. In the same time we tested if the number of bacteria or change of incubation temperature affects survival of this bacteria. In our experiments we used two different doses of L. longbeachae (A5H5 strain) of 108 CFU/ml and 1010 CFU/ml, and inoculated them in 100 ml of sterile tap water, which pH were corrected (pH 2, 5, 7 and 8). Samples were incubated on 25oC and 37oC during 60 days. We determined the number of bacteria in different time points. At pH 2 L. longbeachae survived 3 days after inoculation of 108 CFU/ml, apropos 5 days after inoculation of 1010 CFU/ml at 25oC. At incubation on 37oC Legionella survived shorter time. At pH 5, 7 and 8, after inoculation of 1010 CFU/ml at 25oC after 60 days bacteria still can be detected. If we change the temperature of incubation (37oC) and decrease number of bacteria exposed to those conditions (108 CFU/ml), bacterium lives shorter time. The number of bacteria in inoculum and the temperature of incubation affects survival of L. longbeachae at different pH values of water. The higher number of bacteria and lower temperature of incubation prolong survival of bacterium in unfavourable conditions.

The Cu-containing nitrite reductase from Alcaligenes faecalis S-6 catalyzes the one-electron reduction of nitrite to nitric oxide (NO). Electrons enter the enzyme at the so-called type-1 Cu site and are then transferred internally to the catalytic type-2 Cu site. Protein film voltammetry experiments were carried out to obtain detailed information about the catalytic cycle. The homotrimeric structure of the enzyme is reflected in a distribution of the heterogeneous electron-transfer rates around three main values. Otherwise, the properties and the mode of operation of the enzyme when it is adsorbed as a film on a pyrolytic graphite electrode are essentially unchanged compared to those of the free enzyme in solution. It was established that the reduced type-2 site exists in either an active or an inactive conformation with an interconversion rate of similar to 0.1 s(-1). The random sequential mechanism comprises two routes, one in which the type-2 site is reduced first and subsequently binds nitrite, which is then converted into NO, and another in which the oxidized type-2 site binds nitrite and then accepts an electron to produce NO. At high nitrite concentration, the second route prevails and internal electron transfer is rate-limiting. The midpoint potentials of both sites could be established under catalytic conditions. Binding of nitrite to the type-2 site does not affect the midpoint potential of the type-1 site, thereby excluding cooperativity between the two sites.

Acidic characteristics of various inorganic materials, such as silica gel, aluminum, and titanium(IV) oxides, original and modified with F- and SO 4 2- ions, in the form of hydrogels and nanostructured powders doped by copper(II) ions, are studied. It is shown that pH values inside pores of the studied sorbents (pHintr) differ from the pH of external solutions by 0.5-1.1 units. In the pores of original γ-Al 2O3, the pHintr values are higher, while, in pores of γ-Al2O3 samples modified with F- Ee Cyrillic sign SO 4 2- , as well as nonmodified α-Al2O3, SiO2 gel, and TiO2 hydrogels, pHintr are lower compared to the pH of the external solution. It is found that pHintr decreases, as the content of Cu2+ ions in the TiO2 phase grows, and, beginning with a certain moment, it coincides with pH of an equilibrium solution. The pK a values of functional group dissociation in some materials are determined. It is shown that, using spin probes, that is, pH-sensitive nitroxyl radicals, the electrostatic potential of the surface of nanostructured TiO 2 can be estimated. © 2007 Pleiades Publishing, Ltd.

The kinetics of the assembly of two complementary fragments of oxidized horse heart cytochrome c (cyt c), namely the heme-containing fragment-(1-56) and the fragment-(57-104), have been characterized at different pH values. At neutral pH the fragment-(1-56) is hexacoordinated and has two histidines axially ligated to the heme-Fe(III) (Santucci, R., Fiorucci, L., Sinibaldi, F., Polizio, F., Desideri, A., and Ascoli, F. (2000) Arch. Biochem. Biophys. 379, 331-336), thus mimicking what occurs in the folding intermediate of cyt c. The kinetics of the formation of the complex between the two fragments are characterized at pH 7.0 by a slow rate constant that is independent of the concentration of the reactants; conversely, at a low pH the kinetics are much faster and depend on the concentration of the fragments. This behavior suggests that the rate-limiting step observed in the recombination process of the fragments at neutral pH (that leads to the final coordination of Met-80) has to be ascribed to the detachment of the "misligated" histidine. Thus, the faster recombination rate at a low pH can be related to the fact that histidine is protonated and not able to coordinate to the metal. Furthermore, the independence of the rate constant on the concentration of the reactants observed at pH 7.0 can be accounted for by the occurrence of a conformational transition, which takes place immediately after the two fragments collapse together, likely simulating what induces the detachment of the misligated histidine during cytochrome folding.

Variants of the copper-containing nitrite reductase (NiR) of Alcaligenes faecalis S6 were constructed by site-directed mutagenesis, by which the C-terminal histidine ligand (His145) of the Cu in the type-1 site was replaced by an alanine or a glycine. The type-1 sites in the NiR variants as isolated, are in the reduced form, but can be oxidized in the presence of external ligands, like (substituted) imidazoles and chloride. The reduction potential of the type-1 site of NiR-H145A reconstituted with imidazole amounts to 505 mV vs NHE (20degreesC, pH 7, 10 mM imidazole), while for the native type-1 site it amounts to 260 mV. XRD data on crystals of the reduced and oxidized NiR-H145A variant show that in the reduced type-1 site the metal is 3-coordinated, but in the oxidized form takes up a ligand from the solution. With the fourth (exogenous) ligand in place the type-1 site is able to accept electrons at about the same rate as the wt NiR, but it is unable to pass the electron onto the type-2 site, leading to loss of enzymatic activity. It is argued that the uptake of an electron by the mutated type-1 site is accompanied by a loss of the exogenous ligand and a concomitant rise of the redox potential. This rise effectively traps the electron in the type-1 site.

Twenty-three reindeer bulls, aged 2-3 years, fed during two winter months at the Vuolda reindeer research station in Arjeplog, Sweden, were used in the study. The first group of eight reindeer was moved from their feeding corral to a selection corral, captured by lasso and stunned with a captive bolt outside the selection corral. The second group of seven reindeer was moved to the selection corral, captured by lasso and restrained, after which they were loaded onto a lorry- and transported for 1 hour and then slaughtered. The third group of eight reindeer was moved to the selection corral and herded directly onto the lorry, without any manual handling. They were transported for 5 h and then slaughtered. In both transport groups, four reindeer were fitted with pre-programmed automatic blood sampling equipment (ABSE). ABSE sampled blood at predetermined times via a jugular vein catheter. Ultimate pH-values in three muscles (Mm. longissimus, triceps brachii and biceps femoris) were significantly lower in the group carefully handled and transported for 5 h compared with the other two groups. The physiological mechanisms behind these results are discussed. Samples from M. semimembranosus were collected at slaughter and after 2, 6 and 10 days of refrigerated storage (+4 °C). The samples were analysed for total counts of aerobic bacteria (pour-plated in Tryptone Glucose Extract Agar, Difco, incubated at 20 °C and 30 °C, respectively for 72 h), coliform bacteria 37 °C (pour-plated in Violet Red Bile Agar, Oxoid, incubated at 37 °C for 24 h), Enterococci (surface-plated onto Slantez and Bartley Agar, Oxoid, incubated at 44 °C for 48 h) and Bacillus cereus (surface-plated onto Blood Agar Plates (Blood Agar Base, Difco, supplemented with 5% defibrinated horse blood) 30 °C for 24 h). All samples fell in the range 'fit for consumption'. At slaughter, there was no difference in ASAT activity, urea and Cortisol concentrations between the two transported groups. However, the plasma ASAT activity and urea concentrations at slaughter were significantly lower in the non-transported group. In both transport groups, the plasma Cortisol concentrations increased during loading onto and unloading from the lorry. Abomasal lesions were observed in all treatment groups. It was concluded that reindeer showed an acute stress response to manual handling and transport.

Third stage larvae of the nematode Anisakis simplex (L3) were isolated by pepsin (artificial) digestion from hipaxial muscles from Atlantic mackerel (Scomber scombrus L.).

The changes of S. aureus population was examined during the manufacture of white cheese from naturally contaminated raw milk. Population of S. aureus survived during the manufacture and storage of white cheese. During the manufacture of white cheese population of S. aureus increased from 5,69 log cfu/ml of milk to 6,81 log cfu/g of coagulum and to 7.35 cfu/g of curd and then decreased to 7,10 log cfu/g of cheese. During white cheese storage at + 4º/C for ten days population of S. aureus decreased for 1,11 log clu/g. The mean value of total number of S. aureus in the cheese on the first day was 6,97 log clu/g, and on the tenth day was 5,86 log cfu/g. Decreasing number of S. aureus during storage of white cheese correlated with decreasing of pH values in the cheese. . Praćena je promena populacije S. aureus tokom proizvodnje belog sira iz sirovog mleka prirodno kontaminiranog ovim mikroorganizmom. Utvrđeno je da S. aureus preživljava proces proizvodnje belog sira. Populacija S. aureus se za vreme proizvodnje belog sira povećavala sa 5,69 log cfu/ml sirovog mleka na 6.81 log cfu/g gruša odnosno na 7,35 log cfu/g grude, a zatim se smanjila na 7.10 log cfu/g sira. Tokom čuvanja deset dana pri + 4ºC populacija S. aureus se smanjila za 1,11 logaritamskih jedinica. Srednja vrednost broja S. aureus u siru starom jedan dan je iznosila 6,97 log cfu/g, a desetog dana dana 5,86 log cfu/g. Smanjenje broja S. aureus u siru, tokom skladištenja, bilo je u korelaciji sa padom pH vrednosti u siru. .

Chemistry Department, Bhavan's R. A. College of Science, Khanpur, Ahmedabad-380001, India Manuscript received 22 April 1974; accepted 3 April 1975 A Chromatographic Study of some Reactive Dyestuff.

Twenty-three endoscopically healed duodenal ulcer patients entered a long-term treatment with pirenzepine for 1 year (two 25-mg tablets at breakfast and two tablets at bedtime). One day before and 7 days after the long-term treatment started, gastric pH and BAO were measured in each patient after fasting. The patients were clinically examined monthly and underwent endoscopy 4, 8 and 12 months after the trial started or when they complained of ulcer symptoms. Blood and urine laboratory tests were carried out before treatment began and 6 and 12 months afterwards. Eighteen of the 22 patients that completed the trial (82%) did not relapse. The statistical analysis tended to show a relationship between absence of pH increase and relapses. No severe side-effects or changes in the results of laboratory tests were observed.

A survey of epilithic filamentous algae was carried out at 15 sites on 10 streams with a range of mean pH from 4.37 to 6.67 in the Loch Ard area of the Trossachs, between 1986 and 1988. Monitoring of physical and chemical parameters was carried out in parallel. Photosynthetically Available Radiation (PAR) was measured using electronic integrators developed during the course of the study.Samples of epilithic algae were taken from natural and artificial substrates( microscope slides) to determine the relative contribution of different species to the community structure. Taxa could not be identified to species level in most cases, and are described by genus and cell diameter. Forty-nine taxa were distinguished in the filamentous algal communities found. Relative abundance of taxa was estimated. The mean value of abundance was calculated for use in subsequent statistical analyses. As an alternative, presence-absence(p/a) on each occasion was scored,a nd a mean value (pooled p/a) similarly calculated. Samples were taken also to determine algal biomass, as acetone or methanol extractable pigments (chlorophyll a and carotenoid) and ash-free dry weight (AFDW).The community structure at the different sites was investigated using statistical ecology computer programs. Using Inverse Association Analysis and Canonical Correspondence Analysis, distinct species assemblages were found in sites with mean pH values towards the extremes of the range encountered. Using Normal Association Analysis, Cluster Analysis and Canonical Correspondence Analysis, it was shown that sites are separable on the basis of the species they contain into groups related by mean pH. Using the results of Canonical Correspondence Analyses carried out by the program CANOCO (Ter Braak, 1988) on one half of the data set, field pH may be inferred from the species data, showing the indicator value of the community structure. In all analyses it was found that the pooled p/a data gave essentially the same result as the relative abundance data.The effects of changes in the pH and Aluminium content of water on the growth rate of selected species of green algaewas investigated using a laboratory-scale recirculating miniature artificial stream apparatus which allowed six variations to be tested at one time. Algae were grown attached to microscope slides. Growth rates were measured by counting cells in individual filaments over several successive time intervals. Mixed cultures of up to eight species were employed.Species characteristic of the lower-pH streams such as Hormidium subtile, Geminella 8μm. Stigeoclonium 5μm. and some species of Mougeotia have a pH optimum for growth rate between pH 4.5 and 5.5. Species characteristic of circumneutral streams, Draparnaldia sp. Stigeoclonium 8μm. and Oedogonaum species, have a pH optimum between pH 5.0 and 6.0 or above. Hormidium subtile and Geminella 8μm. can grow at a reduced rate in a monomeric Aluminium concentration of 200 μg litre to the power -1 in which the majority of species tested are rapidly killed. Evidence was found for ecotypes with respect to pH in the genus Stigeoclonium.Biomass in natural waters was positively correlated with pH in contrast to some previous reports. In mixed cultures inthe laboratory, the maximum biomass developed was in the range pH 4.5 to 5.5. around the pH optimum of the speciespresent. At higher pH values (5.5 to 6.0) diatoms were predominant giving a brown-coloured periphyton layer whichis less visually obtrusive than the bright green growth of the filamentous chlorophytes. Therefore anecdotal reports ofan increased biomass upon acidification may reflect only a shift to more visible species. Inhibition of diatom growth byGermanium addition provided no evidence in favour of competition between diatoms and chlorophytes.Differences in community structure and changes in biomass with pH in laboratory culture cannot be ascribed to changesin invertebrate grazing or heterotrophic microbial activity. It is concluded therefore that - differences between speciesin tolerance towards pH or associated water chemistry variables are sufficient to explain differences in algal community structure in the field.

Microbial and physicochemical changes during the ripening of the Croatian traditionally fermented sausages was studied. Three batches of sausages were produced under controlled conditions according to the standard procedure. Lactic acid bacteria constituted the dominant microbial flora (7– 8 log10 cfu g-1 in the final product), while coagulase-negative cocci were found in small numbers (2– 3 log10 cfu g-1) just in the second phase of ripening (between 14 and 28 days). An important finding was the high number of yeasts (4– 5 log10 cfu g-1), which have an important role in the evolution of sensory features of fermented sausages. During the fermentation phase, the pH values rapidly decreased (from initially 6.15 to 5.20 on day 7), resulting in a progressive elimination of the population of enterobacteria and pathogenic staphylococci present at the beginning of the fermentation process. Among the lactic acid bacteria isolated, the predominant genus was Lactobacillus, with prevalence of Lactobacillus plantarum. The collected isolates of coagulase negative cocci were determined as Staphylococcus (S.) xylosus, S. capitis, S. carnosus and S. saprophyticus.The sensory evaluation of sausages showed some deficiencies due to the prolongation of the regular ripening time.

The aim of this study was to determine the influence of three parameters (temperature, water content and type of flour) on the rate of pH value during fermentation of bread dough produced with sourdough. Fermentations of sourdough were conducted according to following experimental design: at three fermentation temperatures (25, 30 and 35 °C), using two types of flour (T-400 and T-1100) and two different water contents during 20 hours. Sourdough produced by the fermentation with Lactobacillus brevis L-62 was used for bread dough fermentation. Different rates of change in pH per minute (RCpH) for all analyzed samples were calculated. According to experimental data and calculated kinetic parameters, neither of analyzed parameters had statistically significant influence on pH profile during bread dough fermentation. Sourdough fermented on 30 °C could be selected as an optimal, because at this temperature pH values of bread dough decreased more rapidly, except sourdough produced from T-400 flour type and 1:1 water:flour ratio. It leads to assumption that the most of lactic acid bacteria actions occur during sourdough fermentation, whereas their influence on bread dough fermentation is considerably fewer. From that reason, influence of selected parameters on pH value changes during bread dough fermentation was considerably lower.