Low Calcium Concentrations Research Articles

Обмен кальция и остеопороз у больных ишемической болезнью сердца в пожилом и старческом возрасте

im. To analyze the relationship between calcium and various clinical and laboratory parameters in old and very old patients with coronary artery disease (CAD) based on the determination of the blood concentration of ionized calcium and daily excretion of calcium in the urine. Materials and methods. This work was a cross-sectional study enrolled 102 patients (84 women and 18 men) with coronary artery disease with a mean age of 83.0±5.9 years. The blood level of ionized calcium (N 1.16–1.32 mmol/l), daily excretion of calcium in the urine (N 2.5– 7.5 mmol/l) and concentration of 25-hydroxycalciferol (25(OH)D) were determined in all patients. Along with this, the bone mineral density of the lumbar spine and proximal femur was analyzed using dual-energy x-ray absorptiometry. Results. The mean daily excretion of calcium in the urine was 1.39±1.1 mmol/l (0.17–7.44 mmol/l). 84.4% of patients had low calcium content in daily urine. The mean blood concentration of ionized calcium was 1.26±0.05 mmol/l (1.16–1.53 mmol/l). Hypercalcemia was observed in 8.3% of patients. Osteoporosis in the proximal femur was registered in 32.9% of patients, in the lumbar spine – in 18.1% of patients. In patients with normal vitamin D level the mean urinary calcium excretion was 1.77±1.2 mmol/l, with vitamin D deficiency – 1.1±0.7 mmol/l (p=0.07). In patients with low calcium excretion in the urine, the mean blood concentration of vitamin D was 18.7±7.7, with normal excretion – 28.5±10.8 ng/ml (p=0.007). Significant inverse relationships were registered between urinary calcium excretion and creatinine (r=-0.36; p<0.0001). In the group of patients with low urinary calcium excretion the mean creatinine level reached 102.3±23.9 µmol/l, with normal excretion – 84.9±11.2 µmol/l (p<0.0001). There was a significant direct correlation between daily urinary calcium excretion and glomerular filtration rate, estimated using the CKD-EPI formula (r=0.39; p<0.0001) and an inverse correlation between blood calcium and GFR (r=-0.26; p=0.01). Significant direct relationship was registered between the blood concentration of ionized calcium and the creatinine (r=0.2; p=0.05) and urea (r=0.32; p=0.04) concentration. Conclusion. The study results demonstrate a low level of calcium excretion in the urine in old and very old patients with coronary artery disease. The urine calcium excretion is primarily due to impaired renal function and low vitamin D concentration.

Increasing Phosphorus Intake Reduces Urinary Concentrations of Magnesium and Calcium in Adult Ovariectomized Cats Fed Purified Diets

We assessed the phosphorus requirement of adult cats and the relationship between phosphorus intake and the fecal and urinary excretion of calcium, magnesium and phosphorus. Female cats (ovariectomized at the onset of sexual maturity) were fed purified diets containing 4.6, 9.2, 18.4 or 27.7 mmol phosphorus/MJ in a 4 × 4-wk crossover study. During the experiment, balance studies were performed and blood samples were taken. A dietary level of 4.6 mmol phosphorus/MJ was found to be sufficient to maintain phosphorus balance and normal plasma concentrations of phosphorus in the adult ovariectomized cats. Increasing levels of dietary phosphorus in the form of NaH2PO4·2H2O caused lower urinary pH values, lower urinary concentrations of calcium and magnesium, and higher urinary concentrations of phosphorus. When dietary levels of phosphorus were raised, the percentage of apparent absorption of magnesium was lower, whereas that of phosphorus was higher. Although it could be predicted that dietary phosphorus levels higher than the National Research Council recommendation of 9.2 mmol/MJ markedly reduced urinary struvite saturation, these higher levels are discouraged because they are associated with lower plasma phosphorus concentrations and creatinine clearance.

Rheological behaviour, hydration, and microstructure of self-compacting concrete incorporating ground ferronickel slag as partial cement replacement

Self-compacting concrete (SCC) is a special type of concrete which has some additional requirements beyond those of traditionally vibrated concrete, such as high flowability and consolidation by self-weight without any segregation of the ingredients. In this research, the production of SCC has been investigated by utilizing a metallurgical by-product, namely ferronickel slag (FNS) to enhance the green supply chain in concrete industry. FNS at 40% replacement of natural sand, and ground ferronickel slag (GFNS) at the rates of 0%, 20%, 35%, and 50% replacement of cement was used, and the rheological, hydration, strength, and microstructural development of SCC are presented in this paper. The fresh properties were assessed by rheology, slump flow, T50, V-funnel, J ring, L-box, U-box, and visual stability index tests. The heat of hydration was determined by isothermal calorimetry, and scanning electron microscope, energy dispersive x-ray spectroscopy, and x-ray powder diffraction techniques were used for microstructural analysis. The results were evaluated against the recommendations of the European and Japanese standards for SCC. Increases in fluidity and workability and decreases in yield stress and viscosity were observed with the increase in GFNS content. Delayed hydration heat was observed with the use of GFNS. The low calcium content of GFNS is attributed to this retardation. The 28 days compressive strength decreased from 79 MPa for the control mix by 16% due to 35% cement replacement by GFNS. This is considered reasonable due to the use of low-calcium GFNS as a cement replacement. The heterogeneous and porous morphology of the microstructure of GFNS incorporated SCC is ascribed to this decrement. Considering both fresh and hardened properties, the GFNS incorporated SCC mixtures are found comparable to the control SCC mixture. Therefore, FNS can be used as a promising alternative ingredient for SCC to strengthen the eco-friendly supply chain and sustainable waste management.

Serum 1,25-dihydroxyvitamin D levels in the diagnosis and pathogenesis of nutritional rickets – a multivariable re-analysis of a case-control study

BackgroundA multivariable logistic regression model resulting from a case-control study of nutritional rickets in Nigerian children suggested that higher levels of serum 25(OH)D may be required to prevent nutritional rickets in populations with low-calcium intakes. ObjectivesThis current study evaluates if adding serum 1,25-dihydroxyvitamin D [1,25(OH)2D] to that model shows that increased levels of serum 1,25(OH)2D are independently associated with risk of children on low-calcium diets having nutritional rickets. MethodsMultivariable logistic regression analysis was used to model the association between serum 1,25(OH)2D and risk of having nutritional rickets in cases (n = 108) and controls (n = 115) after adjusting for age, sex, weight-for age z-score, religion, phosphorus intake and age began walking and the interaction between serum 25(OH)D and dietary calcium intake (Full Model). ResultsSerum 1,25(OH)2D levels were significantly higher (320 pmol/L vs. 280 pmol/L) (P = 0.002), and 25(OH)D levels were lower (33 nmol/L vs. 52 nmol/L) (P < 0.0001) in children with rickets than in control children. Serum calcium levels were lower in children with rickets (1.9 mmol/L) than in control children (2.2 mmol/L) (P < 0.001). Dietary calcium intakes were similarly low in both groups (212 mg/d) (P = 0.973). In the multivariable logistic model, 1,25(OH)2D was independently associated with risk of having rickets [coefficient = 0.007 (95% confidence limits: 0.002–0.011)] after adjusting for all variables in the Full Model. ConclusionsResults confirmed theoretical models that in children with low dietary calcium intake, 1,25(OH)2D serum concentrations are higher in children with rickets than in children without rickets. The difference in 1,25(OH)2D levels is consistent with the hypothesis that children with rickets have lower serum calcium concentrations which prompt the elevation of PTH levels resulting in an elevation of 1,25(OH)2D levels. These results support the need for additional studies to identify dietary and environmental risks for nutritional rickets.

Mechanical strength and the degradation mechanism of metakaolin based geopolymer mixed with ordinary Portland cement and cured at high temperature and high relative humidity

Geopolymer is a new type of eco-friendly cementitious material, and its superior drying and high temperature resistance has been widely recognized. The service performance of geopolymer under 150 °C high-temperature hydrothermal conditions is still less discussed. In this paper, the mechanical strength of pure metakaolin system with low calcium content and metakaolin-cement system with high calcium content under hydrothermal and non-hydrothermal conditions were studied. The results show that under 150 °C hydrothermal conditions, the strength of pure metakaolin geopolymer sharply decreases by reduction rate of 81.8% compared to the sample under 150 °C drying conditions, while the strength of metakaolin-cement geopolymers is well retained with only a slight decrease of 14.4%. This is mainly because the predominantly hydration product sodium aluminosilicate (N-A-S-H) gel of pure metakaolin system undergoes the process of “dissociation–repolymerization–crystallization” under 150 °C hydrothermal conditions, resulting in the loss of cementation ability and obvious deterioration of mechanical strength. In the metakaolin-cement system, the high-calcium calcium silicate gel (C-A-S-H) gel maintains a stable structure, thereby maintaining the macroscopic strength of the material under the hydrothermal conditions.

Identifying the Biomarker Profile of Pre-Frail and Frail People: A Cross-Sectional Analysis from UK Biobank.

This study aimed to compare the biomarker profile of pre-frail and frail adults in the UK Biobank cohort by sex. In total, 202,537 participants (67.8% women, aged 37 to 73 years) were included in this cross-sectional analysis. Further, 31 biomarkers were investigated in this study. Frailty was defined using a modified version of the Frailty Phenotype. Multiple linear regression analyses were performed to explore the biomarker profile of pre-frail and frail individuals categorized by sex. Lower concentrations of apoA1, total, LDL, and HDL cholesterol, albumin, eGFRcys, vitamin D, total bilirubin, apoB, and testosterone (differences ranged from -0.30 to -0.02 per 1-SD change), as well as higher concentrations of triglycerides, GGT, cystatin C, CRP, ALP, and phosphate (differences ranged from 0.01 to 0.53 per 1-SD change), were identified both in pre-frail and frail men and women. However, some of the associations differed by sex. For instance, higher rheumatoid factor and urate concentrations were identified in pre-frail and frail women, while lower calcium, total protein, and IGF-1 concentrations were identified in pre-frail women and frail women and men. When the analyses were further adjusted for CRP, similar results were found. Several biomarkers were linked to pre-frailty and frailty. Nonetheless, some of the associations differed by sex. Our findings contribute to a broader understanding of the pathophysiology of frailty as currently defined.

Environmentally friendly comprehensive recycling utilization technology of foundation engineering slurry

A set of environmentally friendly comprehensive recycling utilization technology was developed to occupy fewer land resources and realize the recycling of engineering slurry. In this study, the engineering slurry was divided into circulating and waste slurries. The technology of “desanding plus reusing of purified slurry and drill cuttings” can be adopted to the circulating slurry, and the technology of “lowering calcium concentration, pH control, flocculation separation, pressure filtration and recycling of wastewater and mud cakes” can be adapted to the waste slurry. For the purified slurry and drill cuttings obtained from the circulating slurry, the former can be directly recycled in foundation engineering, and the latter can be directly used to cultivate grass seeds, with an average germination rate of 62.22%. Wastewater and mud cakes were collected from the flocculating substances after pressure filtration. With the addition of 2% sodium bicarbonate, the wastewater satisfied the mud-making requirements of foundation engineering. Moreover, mud cakes mixed with 30–60% nutrient soil can be used to cultivate grass, with an average germination rate of 72%. The germination rate of Phi alkali grass exceeded 80% in a field trial with drill cuttings from an underground diaphragm wall project, whereas that of ryegrass and slope king grass was 100% with drill cuttings from a geothermal well project. This method can realize the comprehensive recycling utilization of all drill cuttings (or mud cakes) and purified slurry (or wastewater).

Growth studies in commercial broiler birds offered citric acid in formulated feed with low mineral density.

Study of 35days was conducted to evaluate citric acid (CA) as an additive in poultry broiler feed with lower mineral content of calcium (Ca) and total phosphorus (TP) in commercial broiler poultry birds for its effect on growth, nutrient utilization, carcass characteristics, and economics. Vancobb-400 strain day old broiler chicks were divided into four main treatment groups T0, T1, T2, and T3. Treatment groups were further divided into eight replicates with ten chicks in each. T0 served as control, given standard corn-soy flakes-based ration (Pre-starter %: Crude protein (CP)-23, Ca-1.00, TP-0.70; Starter %: CP-22, Ca-1.10, TP-0.72, and Finisher %: CP-20, Ca-0.99, TP-0.70). Treatment T1 served as positive control with added 0.5% CA (Pre-starter %: CP-23, Ca-1.00, TP-0.70; Starter %: CP-22, Ca-1.10, TP-0.72 and Finisher %: CP-20, Ca-0.99, TP-0.70). Treatment T2 was given feed containing 0.5% CA with low Ca and TP content (Pre-starter %: CP-23, Ca-0.90, TP-0.66; Starter %: CP-22, Ca-0.99, TP-0.71 and Finisher %: CP-20, Ca-0.90, TP-0.69), whereas treatment T3 was given feed containing 0.5% CA with moderately low Ca and TP content (Pre-starter %: CP-23, Ca-0.80, TP-0.65; Starter %: CP-22, Ca-0.88, TP-0.70 and Finisher %: CP-20, Ca-0.79, TP-0.68). Birds offered moderately low Ca and TP with 0.5% CA addition, exhibited higher growth rate (P < 0.05), better nutrient utilization with positive influence on dressing percentage and forequarters weight. Economics of broiler feeding revealed that 0.5% CA supplementation fetched highest gross return above feed cost in broiler birds offered feed with moderately low Ca and TP content whereas lowest profit was recorded in feed with low content of Ca and TP. In conclusion, supplementation of 0.5% CA in feed with low and moderately low Ca and TP content positively influenced overall growth, and carcass characteristics. Economics of broiler feeding with moderately low Ca and TP content revealed highest profit with CA (0.5%) supplementation.

Respostas de plantas de tangor Murcott IAC 221, supridas com cálcio,à infecção por Alternaria alternata

Abstract Alternaria brown spot - ABS (Alternaria alternata) causes lesions on fruits, leaves and branches of mandarins. The cost of fungicide application is high and alternative managements for the control need to be studied. We aimed to evaluate calcium (Ca) nutrition to mitigate the effects of ABS. Murcott IAC 221 tangor plants were nourished with calcium nitrate at three different concentrations (30, 150 and 300 mg Ca L-1), and the N content was standardized in the nutrient solution of the treatments (245 mg L-1 of N) with ammonium nitrate. In vitro and in vivo tests were installed, evaluating the severity and area under the disease progress curve (AUDPC), total proteins, peroxidase (POX), catalase (CAT), superoxide dismutase (SOD) and hydrogen peroxide (H2O2), during four times. In all evaluations a negative correlation was observed between leaf Ca content and the severity and AUDPC of ABS. On the other hand, there was a positive correlation between N and the occurrence of the disease. In the treatment with the lowest concentration of calcium there was accumulation of H2O2 and hypersensitivity reaction (HR), with low detoxification of H2O2 by CAT. There is potential for use of calcium supply to plants of Murcott IAC 221 tangor as an alternative management against the fungus A. alternata.

Radiação e condições de temperatura pré colheita determinam a suscetibilidade dos frutos do tomate a danos causados pelo frio pós-colheita

ABSTRACT The aim of this work was to improve the understanding about the relationship between solar radiation and temperature exposure during crop and tomato fruit susceptibility to postharvest chilling injury. Two preharvest treatments were applied: direct sunlight exposed plants (Ex) and shaded plants (Sh). After harvest, fruit were stored at 10⁰C and 4⁰C for ten days. Then, fruit were removed from the chambers and stored at room temperature for four days. Several determinations were carried out: total mineral and calcium content, fruit quality and postharvest parameters, ions leakage and thiobarbituric acid reactive species content and chilling injury index (CII). Ex fruit had higher values of chilling injury index than the Sh fruit, and at the same time, fruit under 4⁰C storage treatment presented a more marked damage than those stored at 10⁰C, demonstrating that accumulated radiation in the field, as a result of a higher solar radiation exposure, is a critical factor affecting postharvest chilling injury susceptibility. The lower calcium content in the Ex fruit could be one of the causes of their response to chilling.

ИЗМЕНЧИВОСТЬ И ЭКОЛОГИЧЕСКОЕ СОСТОЯНИЕ РИСОВЫХ ПОЧВ РОСТОВСКОЙ ОБЛАСТИ (НА ПРИМЕРЕ РИСОВОЙ СИСТЕМЫ ООО «МАНЫЧ-АГРО»)

Purpose: to study the soil properties in the rice system at Manych-Agro LLC, to determine their variability in the space of rice paddies and to assess the ecological state of soils. Materials and methods. On a representative plot, the groundwater table level (GWL), water-physical and physico-chemical properties of soils under different crops of rice crop rotation were studied. Soil samples in non-irrigated plots were also taken for comparative analysis (sunflower, winter wheat and alfalfa). Results. It was revealed that the soils in the arable layer of rice system of Manych-Agro LLC are characterized mainly by weak salinity, gypsum-bearing layers in depth. There is practically no alkalinity, but magnesium alkalinity prevails in the absence of sodium one and low content of exchangeable calcium in the soil absorbtion complex (SAC) in the 40-cm layer (from 60 to 72 % of the total SAC). The humus content is low to very low. The above mentioned negative properties of soils contribute to their strong compaction. Variability of soil properties indicators in space is different. The most significant soil variability was found in salinity (V = 103 %) and solonetzization of soils (V = 25...40 %), and insignificant – in exchangeable calcium (V = 10 %). Humus has an average variability (V = 16 %) for rice fields. Conclusions. The ecological state of soils is ambiguous. Exceeding the GWL, loss of humus and the increase in the proportion of magnesium in SAC characterize the situation as an ecological disaster, and an increase in soil compaction and a decrease in the amount of exchangeable calcium form an emergency situation. A relatively satisfactory situation is emerging in terms of soil salinity and exchangeable sodium.

The Influence of Calcium on the Growth, Morphology and Gene Regulation in Gemmatimonas phototrophica.

The bacterium Gemmatimonas phototrophica AP64 isolated from a freshwater lake in the western Gobi Desert represents the first phototrophic member of the bacterial phylum Gemmatimonadota. This strain was originally cultured on agar plates because it did not grow in liquid medium. In contrast, the closely related species G. groenlandica TET16 grows both on solid and in liquid media. Here, we show that the growth of G. phototrophica in liquid medium can be induced by supplementing the medium with 20 mg CaCl2 L-1. When grown at a lower concentration of calcium (2 mg CaCl2 L-1) in the liquid medium, the growth was significantly delayed, cells were elongated and lacked flagella. The elevated requirement for calcium is relatively specific as it can be partially substituted by strontium, but not by magnesium. The transcriptome analysis documented that several groups of genes involved in flagella biosynthesis and transport of transition metals were co-activated after amendment of 20 mg CaCl2 L-1 to the medium. The presented results document that G. phototrophica requires a higher concentration of calcium for its metabolism and growth compared to other Gemmatimonas species.

Fluidised-bed incineration bottom ash as the sole precursor of alkali-activated binders: A comparison with bottom ash from grate incinerators

The novel formulation of alkali-activated binders (AABs) using incineration bottom ash (IBA) from fluidised bed (FB) combustion technology as a sole precursor was assessed. In addition, IBA-FB was compared with IBA from moving grate (IBA-MG) combustion technology. The AABs formulated with IBA-FB (AAB-FB) and IBA-MG (AAB-MG) were also evaluated from a physicochemical, mechanical, and environmental perspective. The results revealed that specific surface area in IBA-FB hinders the retention of kneading water of fresh pastes, affecting the workability, consistency, porosity, and mechanical strength of AAB-FB. Moreover, the low calcium content of IBA-FB requires that the formulated AABs must be cured at higher curing temperatures to ensure the formation of (N,C)ASH gels, while the high calcium content of IBA-MG promotes the formation of CSH gels at room temperature. The compressive strength results demonstrated that AAB-MG (≈ 11 MPa) and AAB-FB (≈ 8 MPa) could be used for non-structural purposes.

GEOLOGIA E GEOQUÍMICA DO STOCK SERRA DO CAPUXU: MAGMATISMO CÁLCIO-ALCALINO DE ALTO-K NO DOMÍNIO RIO PIRANHAS-SERIDÓ, PROVÍNCIA BORBOREMA

O Stock Serra do Capuxu (SSC) está situado na porção setentrional da Província Borborema, na porção sudoeste do Domínio Rio Piranhas-Seridó. O stock intrude rochas gnáissicas do Complexo Caicó, dos quais guarda xenólitos, e trunca feições dúcteis prévias. Ocorrem enclaves tipo MME, localmente com feições de coexistência de magmas (mixing e mingling); e schlierens múltiplos e complexos. O SSC caracteriza-se por rochas leucocráticas (ΣMáficos=7,5-13%) de composição monzogranítica, textura equigranular fina/média, ocorrendo localmente fenocristais de K-feldspato (microclina). K-feldspato+plagioclásio+quartzo constituem mais de 85% modal; biotita é o principal máfico (6-10%); titanita, opacos, allanita e zircão são acessórios; e clorita, mica branca e carbonato ocorrem como produtos de transformações tardi-magmáticas. São rochas bastante evoluídas (SiO2=71,80-73,14), com teores de álcalis elevados (Na2O+K2O=8,25-8,77) e baixos teores de cálcio (CaO=1,23-1,69). Os espectros de elementos terras raras (ETR’s) mostram enriquecimento dos ETR’s leves, em relação aos pesados, com pronunciada anomalia negativa de Európio (Eu/Eu*=0,34-0,44). O índice de saturação em alumina do SSC revela um caráter transicional metaluminoso a peraluminoso (A/CNK=0,98-1,03). Diagramas discriminantes de séries magmáticas revelam, na sua maioria, afinidade química com rochas da série subalcalina (cálcio-alcalina de alto-K) e diagramas classificativos de ambiente tectônico associam o SSC a ambiente dominantemente pós-colisional. Esses dados são corroborados pela idade U-Pb em zircão de 579 Ma encontrada para o stock, sugerindo um alojamento tardi-tectônico para o SSC, consonante com os aspectos de campo do pluton. Postula-se uma fonte litosférica, mas diferente dos dioritos associados, para o SSC, possivelmente fusão de gnaisses do embasamento (baixo grau de fusão, face seus elevados e pouco variados teores de SiO2) gerando um magma já de natureza cálcio-alcalina de alto-K. Rochas com assinaturas similares têm sido denominadas de “Granitos Tipo-I Fracionados”

Impact of Troponin in Cardiomyopathy Development Caused by Mutations in Tropomyosin

Tropomyosin (Tpm) mutations cause inherited cardiac diseases such as hypertrophic and dilated cardiomyopathies. We applied various approaches to investigate the role of cardiac troponin (Tn) and especially the troponin T (TnT) in the pathogenic effects of Tpm cardiomyopathy-associated mutations M8R, K15N, A277V, M281T, and I284V located in the overlap junction of neighboring Tpm dimers. Using co-sedimentation assay and viscosity measurements, we showed that TnT1 (fragment of TnT) stabilizes the overlap junction of Tpm WT and all Tpm mutants studied except Tpm M8R. However, isothermal titration calorimetry (ITC) indicated that TnT1 binds Tpm WT and all Tpm mutants similarly. By using ITC, we measured the direct KD of the Tpm overlap region, N-end, and C-end binding to TnT1. The ITC data revealed that the Tpm C-end binds to TnT1 independently from the N-end, while N-end does not bind. Therefore, we suppose that Tpm M8R binds to TnT1 without forming the overlap junction. We also demonstrated the possible role of Tn isoform composition in the cardiomyopathy development caused by M8R mutation. TnT1 dose-dependently reduced the velocity of F-actin-Tpm filaments containing Tpm WT, Tpm A277V, and Tpm M281T mutants in an in vitro motility assay. All mutations impaired the calcium regulation of the actin-myosin interaction. The M281T and I284V mutations increased the calcium sensitivity, while the K15N and A277V mutations reduced it. The Tpm M8R, M281T, and I284V mutations under-inhibited the velocity at low calcium concentrations. Our results demonstrate that Tpm mutations likely implement their pathogenic effects through Tpm interaction with Tn, cardiac myosin, or other protein partners.

EXPERIMENTAL JUSTIFICATION OF THE PREVENTION OF PERIODONTAL BONE TISSUE DESTRUCTION IN OVARIOECTOMIZED RATS WITH CALCIUM-CONTAINING ADDITIVES

Purpose. Study of periodontoprotective properties of preventive complexes based on calcium, quercetin, vitamins, macro- and microelements in ovariectomized rats with alimentary deficiency of protein and calcium. Materials and methods. The study was conducted on 32 female rats in which pathology of periodontal bone tissue was simulated due to hipoestrogenicity; as well as the prevention of the said pathology with biologically active complexes based on calcium citrate from the shells of Black Sea oysters and "Minerol". Hypoestrogenicity was caused by bilateral ovariectomy, the negative effect of which on bone tissue was further complicated by a diet with a low content of calcium and protein. After 5 months, the animals were removed from the experiment; the degree of atrophy of the alveolar process was determined on the drugs; the content of acid and alkaline phosphatases, elastase, catalase and MDA was determined in the homogenate of the alveolar process. Results. The combination of ovariectomy and an inferior diet caused characteristic inflammatory-dystrophic changes in the bone tissue of the jaws, which are expressed in an increase in the activity of elastase, catalase, and MDA content in the alveolar bone homogenate. Also, under the condition of pathology, an increase in the degree of atrophy of the alveolar process, an increase in the activity of acid and alkaline phosphatases was observed, which indicates a violation of mineralization processes. Prophylactic administration of a complex based on calcium citrate from the shells of Black Sea oysters and a complex based on the biologically active additive "Minerol" showed a pronounced osteoprotective effect, which consisted in the decrease of the degree of the alveolar process atrophy and the reduction of the activity of markers of bone resorption and peroxidation lipids.

Biogeochemical Features of Landscapes of the Nadym Region of YANAO

The purpose of the study is to reveal the biogeochemical features of soils (illuvial-ferruginous podzols, podzols, cryozems, oligotrophic peat frozen soils, alluvial gray-humus and lacustrine-alluvial soils) and vegetation (Betula nana L., Chamaedaphne calyculata (L.) Moench, Vaccinium uliginosum L., Ledum palustre L., Sphagnum sp L.) of the Nadym region. To achieve the goal, the following tasks were set and implemented: to determine the total content and radial differentiation of elements in the studied soils; to reveal the features of the biological accumulation of elements by the dominant types of vegetation cover. The elemental composition of soils and plants was determined on a serial X-ray fluorescence spectrometer S6 JAGUAR according to the method for determining the mass fraction of metals and metal oxides in powder samples. It has been established that the soils of the Nadym region are characterized by a low content of macroelements, including potassium, calcium, and phosphorus necessary for the mineral nutrition of plants. Calculation of soil-geochemical coefficients shows that the studied soils have an average degree of weathering and leaching moisture regime, peat-gley and cryozems are classified as more fertile soils. Ca, P, and S are accumulated in organic soil horizons, and Co, Cr, and Ni are accumulated in mineral horizons. The radial geochemical structure of cryozems combines features of eluvial-illuvial differentiation and biogenic accumulation. In podzols, the distribution of all elements is eluvial-illuvial, with a minimum in the podzolic horizon. Among plants, the leader in the accumulation of elements is dwarf birch (the maximum accumulation of Ca, K, P, Mg, Zn, Ni), in mosses, on the contrary, the minimum accumulation of elements was found. The elements of energetic and strong accumulation (Kb=n-100n) include Pb, Mo, Cd, Cl, S.

Scalant Removal at Acidic pH for Maximum Ammonium Recovery.

One option for new nitrogen sources is industrial liquid side streams containing ammonium nitrogen (NH4-N). Unfortunately, NH4-N often exists in low concentrations in large water volumes. In order to achieve a highly concentrated NH4-Nsolution, scalant removal is needed. In this study, scalant removal by precipitation was investigated. At alkali pH, sodium carbonate (Na2CO3) was used as a precipitation chemical while at acidic pH, the chemical used was oxalic acid (C2H2O4). At alkali pH, high Na2CO3 dose was needed to achieve low content of calcium, which, with sulphate, formed the main scalant in the studied mine water. NH4-N at alkali pH was in the form of gaseous ammonia but it stayed well in the solution during pre-treatment for nanofiltration (NF) and reverse osmosis (RO). However, it was not rejected sufficiently, even via LG SW seawater RO membrane. At acidic pH with CaC2O4 precipitation, NF90 was able to be used for NH4-N concentration up to the volume reduction factor of 25. Then, NH4-N concentration increased from 0.17 g/L to 3 g/L. NF270 produced the best fluxes for acid pre-treated mine water, but NH4-N rejection was not adequate. NF90 membrane with mine water pre-treated using acid was successfully verified on a larger scale using the NF90-2540 spiral wound element.

RAMAN SPECTROSCOPY ANALYSIS OF CORONARY DENTIN OF VITAL AND ENDODONTICALLY TREATED TEETH

PURPOSE: The present study aimed to investigate the properties of coronary dentin of vital and endodontically treated human teeth using Raman Spectroscopy. MATERIAL/METHODS: The samples used were taken from coronary dentin of intact extracted human teeth, ultrasonically cleaned and stored in a 0.2% thymol solution at 4 degrees Celsius for up to 3 months. They were divided into two groups – “vital dentin” and “endodontically treated dentin” samples. Each sample was crossed-sectioned, embedded in resin, polished and subjected to Raman spectroscopy with a Horiba Jobin-Yvon T64000 triple-grating spectrometer, using a CdHe laser with 4 μm diameter of the laser spot and 2.5mW of power on the examined surface. The resultant diagrams were analyzed using the software package Origin 9.6 andunderwent baseline correction and normalization. A comparison between the two studied groups was made. RESULTS: The results from the “vital dentin” group showed a well-expressed crystalline structure, with clear peaks corresponding to pure and b-carbonated hydroxyapatite. The results of the “endodontically treated dentin” group showed the presence of new chemical compounds – octacalcium phosphate, tricalcium phosphate and dicalcium phosphate dihydrate, as well as increased intensity of the b-carbonated hydroxyapatite peaks. CONCLUSIONS: The presence of mineral substances with low calcium content could contribute to a decrease in dentin toughness, which in turn can lessen the mechanical properties of endodontically treated teeth. Raman spectroscopy can be a useful tool in the detection of these dentin components.

One-Part Alkali-Activated Materials: State of the Art and Perspectives.

Alkali-activated materials (AAM) are recognized as potential alternatives to ordinary Portland cement (OPC) to limit CO2 emissions and beneficiate several wastes into useful products. Compared with its counterparts involving the concentrated aqueous alkali solutions, the development of "just add water" one-part alkali-activated materials (OP-AAM) has drawn much attention, mainly attributed to their benefits in overcoming the hazardous, irritating, and corrosive nature of activator solutions. This study starts with a comprehensive overview of the OP-AAM; 89 published studies reported on mortar or concrete with OP-AAM were collected and concluded in this paper. Comprehensive comparisons and discussions were conducted on raw materials, preparation, working performance, mechanical properties, and durability, and so on. Moreover, an in-depth comparison of different material pretreatment methods, fiber types, and curing methods was presented, and their potential mechanisms were discussed. It is found that ground granulated blast-furnace slag (GGBS) provides the best mechanical properties, and the reuse of most aluminosilicate materials can improve the utilization efficiency of solid waste. The curing temperature can be improved significantly for precursor materials with low calcium contents. In order to overcome the brittleness of the AAM, fiber reinforcement might be an efficient way, and steel fiber has the best chemical stability. It is not recommended to use synthetic fiber with poor chemical stability. Based on the analysis of current limitations, both the recommendations and perspectives are laid down to be the lighthouse for further research.