High Calcium Concentrations Research Articles

Identification and antimicrobial sensitivity profiling of bacteria isolated from cultured catfish shing (Heteropneustes fossilis)

The cultivated species of catfish (Heteropneustes fossilis), also known as "Shing" has a delectable flavor, a high market value, a high nutritional and therapeutic value, and a high iron and calcium content. In Bangladesh, the shing (H. fossilis) fish is one of the most sought-after, popular, and extremely valuable indigenous species. The purpose of this research was to isolate bacterial pathogens from infected shing (H. fossilis) fish and determine their antibiotic sensitivity. In total, 76 medically infected shing fish were collected by the cultivators from their own ponds in the Jashore district, in southern Bangladesh. Disease-causing bacteria were found in 62 (81.5%) of the infected fish, while normal flora were found in 14 (18.5%) of the 76 samples. There were 62 pathogenic bacterial isolates found, and Aeromona spp., Pseudomonas spp., Streptococcus spp., Flavobacterium spp. and Vibrio spp. were the main causes of disease in the sick fish. Among the species of bacteria that were isolated, the prevalence of the largest pathogens, Aeromonas spp. was 34 (51.4%) and the prevalence of the second largest, Pseudomonas spp. was 13 (20.3%). The other isolates were comprised of the following species: Streptococcus spp. 9 (9.4%), Flavobacterium spp. 4 (5.4%) and Vibrio spp. 2 (4.1%). The farming of shing (H. fossilis) fish has been increased rapidly all around the country. Therefore, bacterial infections may reduce the production of fish in ponds. In this research, bacterial strains showed a high degree of sensitivity to ciprofloxacin (77%) and levofloxacin (54%). Significantly, oxytetracycline (52%) enrofloxacin (45%) and erythromycin (45%) were the intermediate/moderate sensitive antibiotics. All the strains were found to be resistant to amoxicillin 57/62 (92%) and neomycin 42/62 (68%). The findings of this research will be beneficial to fish farmers in the treatment of bacterial infections in fish, as these diseases are caused by microorganisms. The PCR method might be studied further as a means of identifying all bacterial cultures, which would require additional research.

Electrospun PCL/fibrin scaffold as a bone implant improved the differentiation of human adipose-derived mesenchymal stem cells into osteo-like cells

Bone remodeling is not able to repair the major injuries caused by trauma, cancer, etc. Bone tissue engineering is aimed to provide implants for bone repair or replacement. To approach such a purpose, polymeric scaffolds along with stem cells are used to fabricate a supportive matrix mimicking in vivo microenvironment. Here, we developed an in vivo-like matrix based on polycaprolactone (PCL) and fibrin to enhance the differentiation of human adipose-derived mesenchymal stem cells into osteo-like cells (AD-MSCs). PCL scaffold was fabricated by electrospinning and coated with fibrin. AD-MSCs were cultured and differentiate on PCL and PCL/fibrin. The viability of cultured cells in comparison with tissue culture plate (TCPS) was evaluated by MTT assay on days 1, 2, and 3 of differentiation. The differentiation was compared to TCPS on days 7, 14, and 21 of differentiation. To evaluate the differentiation efficiency, calcium content, alkaline phosphatase (ALP), and expression of RUNX-2, Collagene-I, Osteocalcin, and Osteonectin were assessed in differentiated cells. A slight increase in cell viability was observed in the TCPS group on day 3 of differentiation. Higher calcium content and ALP activity were observed in PCL and PCL/fibrin groups, respectively. The expression of osteogenic genes was higher in the PCL/fibrin group on days 7, 14, and 21 of differentiation. It seems PCL acts synergistically with fibrin to make an in vivo-like microenvironment and enhanced the differentiation of AD-MSCs into osteo-like cells.

Hydrodynamic study of drying on Qisthi Hindi using a Fluidized Bed Dryer

A Fluidized Bed Dryer (FBD) is one of the most efficient and prominent moisture-reducing dryers in the food, chemical, and pharmaceutical industries. This work investigates changes in moisture content and drying rate in the FBD with a dense bed as a perforated plate and uses an indirect heating medium. Here the air flows by the blower and acts as a dryer after passing through the heater to reduce the moisture content contained in the material. Qisthi Hindi can be used as herbal medicine for several diseases such as asthma, cough, diabetes, and liver and stomach problems. It can even be consumed during the COVID-19 pandemic. The Qisthi Hindi root has a fairly high calcium and protein content, so drying must be carried out at moderate temperatures because it is a heat-sensitive material. Drying using FBD is carried out at temperatures ranging from 50-100 °C. On air drying at 50 °C, the protein content increased by 3.13%, calcium content increased by 29% from the levels before drying, and water content decreased by 5.3%. At the drying air temperature of 100 °C, the protein content decreased to 3.87%, and the calcium content decreased by 15% from drying at 50 °C. FBD reduced the moisture content significantly in Qisthi Hindi, which is heat sensitive.

Evaluation of Phytochemical and Mineral Composition of Malaysia’s Purple-Flesh Sweet Potato

Sweet potato (Ipomoea batatas (L.) Lam) is one of Malaysia’s underutilized main crops. However, systematic characterization of phytochemical and mineral contents of the sweet potato tuber and flour is still required for further specific food product development. Therefore, this study aims to evaluate the effects of the peeling conditions on the nutritional composition of sweet potato tuber and flour of the Anggun 1 cultivar. The following properties were investigated in the different peeling conditions of the sweet potato tuber (unpeeled, peeled, and skin only), i.e., the phytochemical properties (total phenolic, total flavonoid, anthocyanin content) and mineral elements (calcium and iron). The results indicated a significant interaction between the peeling conditions of the sweet potato tuber and flour on all the examined properties (p<0.05), total flavonoid content (2615.05 mg quercetin/100g and 3362.96 mg quercetinrties (p < 0.05). The unpeeled sweet potato tuber and flour had the highest value of total phenolic content (3142.98 mg GAE/100g and 4303.80 mg GAE/10/100g), anthocyanin (628.35 mg/100g and 960.30 mg/100g) and iron (5.45 mg/100g for flour only). Moreover, the result had indicated a higher calcium content (701.87 mg/100g) in the skin of the sweet potato. Therefore, this study provides a broad insight into the sweet potato’s phytochemical properties and the mineral composition, which can be used for further specific food product development and processing.

Effect of calcium on the thermal denaturation of whey proteins and subsequent fouling in a benchtop fouling device: An experimental and numerical approach

The key role of calcium in whey protein fouling behavior is well known in plate heat exchangers (PHEs), as it affects both the thermal denaturation of proteins and deposition reaction on the surface. However, the complex flow pattern and the closed configuration of PHEs make it hard to investigate this phenomenon in situ. In this paper, a microchannel benchtop fouling device was designed, making it possible to achieve a similar temperature profile to that performed in PHEs but in a laminar regime. A 3D simulation was developed to predict the thermal denaturation of β-lactoglobulin (BLG) as well as its deposition in the microchannel using computational fluid dynamics (CFD). The thermodynamics and heat transfer of the numerical model was validated by experimentally measuring the bulk fluid temperature profile in the microchannel using fluorescence microscopy, where Pyrromethene 556 was used as a temperature indicator. Results revealed a quasi-linear relationship between the pre-exponential factor of deposition reaction and the calcium concentration, implying that the fouling was built in such a pattern that only one calcium ion per one BLG molecule is involved. The imaging of the fouling deposit in situ showed spherical structures of deposits at low calcium levels, while denser and more rod-like ones were found at higher calcium concentrations. The fouling behavior was found to follow a crystallization-like pattern with preference upon the previously fouled layer instead of clean stainless steel surface. These findings confirm the essential role of ionic calcium on the formation of fouling deposits by anchoring the denatured BLG protein upon the surface as well as strengthening the protein-protein interactions for fouling build-up.

Fabrication and characterisation of novel algin incorporated bioactive-glass 58S calcium-silicate-based root canal sealer

The usage of bioceramic-based root canal sealers has escalated over the years due to their excellent properties. The present study aimed to fabricate a novel algin incorporated bioactive glass 58S calcium-silicate (Bio-G) sealer and characterise its surface microstructure and chemical compositions in comparison to commercially available bioceramic sealers (BioRoot RCS and iRoot SP). The powder form of experimental Bio-G sealer consisted of synthesised BG 58S particle, calcium silicate, zirconia dioxide, calcium carbonate and alginic acid powder as binder. The liquid composed of 5% calcium chloride solution. Five standardised disc specimens were prepared for each sealer group according to the manufacturer's instructions. Subsequently, sealer disc-specimens were placed in an incubator at 37°C, 95% relative humidity for 72h to allow setting prior to testing under scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Experimental Bio-G sealer revealed irregular micro-sized particles ranging from 0.5μm to 105μm aggregated in clusters comparable to those of BioRoot RCS and iRoot SP. EDS microanalysis showed that Bio-G had high content of oxygen, silicon, and calcium, with the presence of aluminium and chloride similar to BioRoot RCS. Meanwhile, the FTIR and XRD findings suggested that all sealers predominantly contained calcium silicate hydrate, calcium carbonate, and zirconium dioxide, while calcium aluminium silicate oxide was detected in Bio-G. The present novel Bio-G sealer demonstrated desirable particle size distribution and acceptable degree of purity. Future studies are warranted to explore its properties and clinical application.

Repression of the antiporter SLC7A11/glutathione/glutathione peroxidase 4 axis drives ferroptosis of vascular smooth muscle cells to facilitate vascular calcification

Vascular calcification is a common pathologic condition in patients with chronic kidney disease (CKD). Cell death such as apoptosis plays a critical role in vascular calcification. Ferroptosis is a type of iron-catalyzed and regulated cell death resulting from excessive iron-dependent reactive oxygen species and lipid peroxidation. However, it is unclear whether ferroptosis of vascular smooth muscle cells (VSMCs) regulates vascular calcification in CKD. Our results showed that high calcium and phosphate concentrations induced ferroptosis in rat VSMCs invitro. Inhibition of ferroptosis by ferrostatin-1 dose-dependently reduced mineral deposition in rat VSMCs under pro-osteogenic conditions, as indicated by alizarin red staining and quantification of calcium content. In addition, gene expression analysis revealed that ferrostatin-1 inhibited osteogenic differentiation of rat VSMCs. Similarly, ferrostatin-1 remarkably attenuated calcification of rat and human arterial rings exvivo and aortic calcification in vitamin D3-overloaded mice invivo. Moreover, inhibition of ferroptosis by either ferrostatin-1 or deferoxamine attenuated aortic calcification in rats with CKD. Mechanistically, high calcium and phosphate downregulated expression of SLC7A11 (a cystine-glutamate antiporter), and reduced glutathione (GSH) content in VSMCs. Additionally, GSH depletion induced by erastin (a small molecule initiating ferroptotic cell death) significantly promoted calcification of VSMCs under pro-osteogenic conditions, whereas GSH supplement by N-acetylcysteine reduced calcification of VSMCs. Consistently, knockdown of SLC7A11 by siRNA markedly promoted VSMC calcification. Furthermore, high calcium and phosphate downregulated glutathione peroxidase 4 (GPX4) expression, and reduced glutathione peroxidase activity. Inhibition of GPX4 by RSL3 promoted VSMC calcification. Thus, repression of the SLC7A11/GSH/GPX4 axis triggers ferroptosis of VSMCs to promote vascular calcification under CKD conditions, providing a novel targeting strategy for vascular calcification.

Leaf elemental composition analysis in spider plant [Gynandropsis gynandra L. (Briq.)] differentiates three nutritional groups.

Understanding the genetic variability within a plant species is paramount in implementing a successful breeding program. Spider plant (Gynandropsis gynandra) is an orphan leafy vegetable and an extraordinary source of vitamins, secondary metabolites and minerals, representing an important resource for combatting malnutrition. However, an evaluation of the leaf elemental composition, using a worldwide germplasm collection to inform breeding programs and the species valorization in human nutrition is still lacking. The present study aimed to profile the leaf elemental composition of G. gynandra and depict any potential geographical signature using a collection of 70 advanced lines derived from accessions originating from Asia and Eastern, Southern and West Africa. The collection was grown in a greenhouse using a 9 × 8 alpha lattice design with two replications in 2020 and 2021. Inductively coupled plasma–optical emission spectrometry was used to profile nine minerals contents. A significant difference (p < 0.05) was observed among the lines for all nine minerals. Microelements such as iron, zinc, copper and manganese contents ranged from 12.59–430.72, 16.98–166.58, 19.04–955.71, 5.39–25.10 mg kg−1 dry weight, respectively, while the concentrations of macroelements such as potassium, calcium, phosphorus and magnesium varied in the ranges of 9992.27–49854.23, 8252.80–33681.21, 3633.55–14216.16, 2068.03–12475.60 mg kg−1 dry weight, respectively. Significant and positive correlations were observed between iron and zinc and calcium and magnesium. Zinc, calcium, phosphorus, copper, magnesium, and manganese represented landmark elements in the genotypes. Eastern and Southern African genotypes were clustered together in group 1 with higher phosphorus, copper and zinc contents than Asian and West African lines, which clustered in group 2 and were characterized by higher calcium, magnesium and manganese contents. An additional outstanding group 3 of six genotypes was identified with high iron, zinc, magnesium, manganese and calcium contents and potential candidates for cultivar release. The genotype × year interaction variance was greater than the genotypic variance, which might translate to phenotypic plasticity in the species. Broad-sense heritability ranged from low to high and was element-specific. The present results reveal the leaf minerals diversity in spider plant and represent a baseline for implementing a minerals-based breeding program for human nutrition.

Phase-transition kinetics of calcium-doped TiO2: A high-temperature XRD study

Controlling titanium dioxide crystallinity is crucial in view of the possible oxide applications. In this study, we examined the effects of calcium doping on the anatase-rutile phase transition via in-situ high-temperature X-ray diffraction. The phase transition temperature of calcium-doped TiO2 was approximately 900 °C, specifically 900 °C, 875 °C, and 900 °C for the 2%, 4%, and 6% calcium-doped TiO2, respectively. The larger radius of the calcium ion compared to that of the titanium ion hindered the calcium incorporation into the TiO2 lattice. Moreover, the hampered titanium-oxygen bond rotation during the phase transition led to an increase in the phase-transformation temperature. Furthermore, at higher calcium concentrations, the corresponding activation energies increased first and then decreased. This may have been controlled by the decreasing nucleation rate during the reaction.

Effect of Coal Blending on Ash Fusibility and Slurryability of Xinjiang Low-Rank Coal

This work investigated the effect of coal blending on ash fusibility and slurryability of Xinjiang low-rank coal. The results showed that Xinjiang low-rank coals were characterized by high internal water content, high volatile content, high ash fusing point, and poor slurryability, which can not be directly used in coal water slurry gasification. The blending method not only reduced the ash fusibility but also improved the slurryability of these low-rank coals. When the coals with low calcium and high silicon contents (KG and YK) were blended with coal with high calcium content (SH), the ash fusion temperatures of the blended coal were significantly reduced. Moreover, the SH coal showed the worst slurryability performance with a concentration of 48.56%. The slurryability of HS coal can be dramatically improved by blending with KG. When the mass fraction of KG coal reached 70%, the concentration of coal water slurry increased by 11%. For the blended coal of KG and YK, the concentration and stability of coal water slurry gradually increase with the increasing mass ratio of KG. The coal blending method can effectively improve the concentration of coal water slurry for the low-rank coals, which were difficult-to-prepare slurry.

Bioremediation of soil contaminated with oil residues using Helianthus annuus and Aspergillus Niger

A study was conducted in the greenhouse / Department of Life Sciences / College of Education / Samarra University on 10/5/2021 and lasted for 4 and a half months. T0P2) The highest conductivity was (4.94) dS. M-1 significantly increased, while the electrical conductivity decreased in treatment T3P2) to (1.93) dS. M-1, and treatment (T3P2) recorded the highest pH value of (7.98), while treatment (T1P1) recorded the lowest value of (7.1), and treatment (T3P0) had the highest percentage of organic matter that reached (3.50) g. kg-1 soil, while the treatment (T2P0) recorded the lowest percentage which is (1.25 gm). kg-1 soil, while treatment T0P1) achieved the highest concentration of dissolved bicarbonate equal to (20.68 cmol. L-1), while the lowest concentration achieved by treatment (T2P1) was (14.40 cmmol. L-1), while the dissolved sulfate was the highest concentration equal to (16.86 cmol. l-1) in treatment (T0P2) and the lowest concentration in treatment (T1P2) is (8.58 cmol. l-1), and the highest concentration of calcium was in treatment (T1P2) equal to (35.37 cmol. l-1).

Shift of calcium-induced Microcystis aeruginosa colony formation mechanism: From cell adhesion to cell division

Colony formation is an essential stage of cyanobacterial blooms. High calcium concentration can promote Microcystis aeruginosa aggregation behavior, but the mechanism of colony formation caused by calcium has rarely been reported. In this study, high calcium-induced colony formation was identified as a shift from cell adhesion to cell division, rather than only cell adhesion as previously thought. Algae responded to this calcium-induced environmental pressure by aggregating and forming colonies. Algal cells initially secreted large quantities of extracellular polysaccharides (EPS) and rapidly aggregated by cell adhesion. The highest aggregation proportion was up to 68.93%. However, high calcium concentrations cannot completely inhibit algal cell growth, but only delay the algae into the rapid growth phase. With adaption to calcium and existing high EPS content, the daughter cells reduced EPS synthesis and the aggregation proportion decreased. The increasing growth rate was also responsible for the decreased xylose content in EPS. The mechanism of colony formation changed to cell division. The downregulation of genes related to EPS secretion also supported this hypothesis. Overall, these results can benefit for our understanding of cyanobacterial bloom formation.

Effects of high Ca and Mg stress on plants water use efficiency in a Karst ecosystem.

BackgroundKarst ecosystems are widely distributed in the world, with one of the largest continuous Karst landforms in Southwest China. Karst regions are characterized by water shortage, high soil calcium (Ca) and magnesium (Mg) content, and soil nutrient leaching, resulting in drought stress and growth limitation of plants.MethodsThis study compared nitrogen (N), phosphorus (P), potassium (K), Ca, and Mg of herbaceous and woody plants in a small Karst ecosystem in Southwest China. The indexes of water use efficiency (WUE) were calculated to identify the drought stress of plants in this Karst ecosystem. Meanwhile, the relationship between Ca and Mg accumulation and WUE was evaluated in herbaceous and woody plants.ResultsHerbaceous plants showed a higher content of leaf N (13.4 to 40.1 g·kg−1), leaf P (2.2 to 4.8 g·kg−1) and leaf K (14.6 to 35.5 g·kg−1) than woody plants (N: 10.4 g to 22.4 g·kg−1; P: 0.4 to 2.3 g·kg−1; K: 5.7 to 15.5 g·kg−1). Herbaceous plants showed a significantly positive correlation between WUE and K:Ca ratio (R = 0.79), while WUE has a strongly positive correlation with K:Mg ratio in woody plants (R = 0.63).ConclusionHerbaceous plants suffered from nitrogen (N) limitation, and woody plants were constrained by P or N+P content. Herbaceous plants had higher leaf N, P, and K than woody plants, while Ca and Mg showed no significant differences, probably resulting from the Karst environment of high Ca and Mg contents. Under high Karst Ca and Mg stress, herbaceous and woody plants responded differently to Ca and Mg stress, respectively. WUE of herbaceous plants is more sensitive to Ca stress, while that of woody plants is more sensitive to Mg stress. These findings establish a link between plant nutrients and hydraulic processes in a unique Karst ecosystem, further facilitating studies of the nutrient-water cycling system in the ecosystem.

Calcium inhibits penetration of Alzheimer's Aβ1 -42 monomers into the membrane.

Calcium ion regulation plays a crucial role in maintaining neuronal functions such as neurotransmitter release and synaptic plasticity. Copper (Cu2+ ) coordination to amyloid-β (Aβ) has accelerated Aβ1-42 aggregation that can trigger calcium dysregulation by enhancing the influx of calcium ions by extensive perturbing integrity of the membranes. Aβ1-42 aggregation, calcium dysregulation, and membrane damage are Alzheimer disease (AD) implications. To gain a detail of calcium ions' role in the full-length Aβ1-42 and Aβ1-42 -Cu2+ monomers contact, the cellular membrane before their aggregation to elucidate the neurotoxicity mechanism, we carried out 2.5μs extensive molecular dynamics simulation (MD) to rigorous explorations of the intriguing feature of the Aβ1-42 and Aβ1-42 -Cu2+ interaction with the dimyristoylphosphatidylcholine (DMPC) bilayer in the presence of calcium ions. The outcome of the results compared to the same simulations without calcium ions. We surprisingly noted robust binding energies between the Aβ1-42 and membrane observed in simulations containing without calcium ions and is two and a half fold lesser in the simulation with calcium ions. Therefore, in the case of the absence of calcium ions, N-terminal residues of Aβ1-42 deeply penetrate from the surface to the center of the bilayer; in contrast to calcium ions presence, the N- and C-terminal residues are involved only in surface contacts through binding phosphate moieties. On the other hand, Aβ1-42 -Cu2+ actively participated in surface bilayer contacts in the absence of calcium ions. These contacts are prevented by forming a calcium bridge between Aβ1-42 -Cu2+ and the DMPC bilayer in the case of calcium ions presence. In a nutshell, Calcium ions do not allow Aβ1-42 penetration into the membranes nor contact of Aβ1-42 -Cu2+ with the membranes. These pieces of information imply that the calcium ions mediate the membrane perturbation via the monomer interactions but do not damage the membrane; they agree with the western blot experimental results of a higher concentration of calcium ions inhibit the membrane pore formation by Aβ peptides.

Co-pyrolysis of paper mill sludge and textile dyeing sludge with high calorific value solid waste: Pyrolysis kinetics, products distribution, and pollutants transformation

Paper mill sludge (PMS) and printing and textile dyeing sludge (TDS) are two typical industrial sludge with high calcium content, high ash content and low calorific value. To attain effective removal of industrial solid waste, in this study, PMS and TDS are first pyrolyzed independently to study their thermochemical behavior. Results show that 600 °C is the optimal pyrolysis temperature for both PMS and TDS from the perspective of organics degradation. However, the yield and quality of pyrolysis oil and gas are still at low level due to the characteristics of high ash content and low organic content, which is not suitable for fuel recovery. Two kinds of organic solid wastes with high calorific value, duckweed (DW) and waste tire (WT), are co-pyrolyzed with PMS and TDS, which can effectively reduce activation energy and increase the yield of liquid and gas products. The most prominent is P1D1 pyrolysis gas, the production of CH4 and C2-C3 increased from 10.80 L/kg and 3.89 L/kg to 20.16 L/kg and 15.58 L/kg respectively, and the high calorific value also increased to 230.93 kJ/kg. The quality of pyrolysis liquid has been improved significantly as the declined N and O-heteroatom content (especially for P1D1 and T1W1) due to the inhibition effect of co-pyrolysis on the N/O migration into pyrolytic liquid. The solid residue from the co-pyrolysis of PMS and DW contains rich N-functional groups and can promote the conversion of pyridinic-N and pyrrolic-N to quaternary-N. Compared with independent pyrolysis, co-pyrolysis can promote the degradation of harmful organic matter in sludge. The addition of DW and WT co-pyrolysis reduced the solid residue yield of PMS by 19.9 wt% and 14.9 wt% (13.4 wt% and 10.5 wt% for TDS). This work provides inspiration for further understanding the safe disposal of PMS and TDS by pyrolysis.

FORMULASI DAN SIFAT ORGANOLEPTIK NUGGET BERBASIS TEMPE DAN SERBUK DAUN KELOR SEBAGAI MAKANAN SELINGAN TINGGI KALSIUM UNTUK LACTO-OVO VEGETARIAN

A problem for vegetarians is the risk of calcium deficiency. Nuggets made from tempeh and moringa leaf powder can be used as an alternative for additional foods that contain calcium so that it is expected to reduce the risk of osteoporosis. This study aims to obtain a formula and determine the effect of the balance of nugget and Moringa leaf powder on the organoleptic properties of nuggets, as well as to determine the calcium levels in each balance. The research design is experimental, the research method used is hedonic test for testing organoleptic properties and spectrophotometry for testing calcium levels. The research was carried out in January 2021 by sending products to the homes of 30 panelists by implementing health protocols related to the COVID-19 pandemic. This nugget formula consists of a balance, with a ratio of tempeh and Moringa leaf powder (%) F1 (97% : 3%) F2 (94% : 6%), and F3 (91% : 9%). The results of statistical tests showed that there was no difference in the aspects of color, taste, texture and overall. As for the aroma, there was a significant difference between the F2 and F3 nuggets. Calcium levels of F1, F2, and F3 produced are 16.4; 16.6 and 16;8 mg/100gr. It is necessary to modify and further research on the manufacture of nuggets with other vegetable protein sources so that the product has a high calcium content so that it can increase calcium in the body, especially for lacto-ovo vegetarians.

Preface: Functional biogeography in Japanese cedar

Preface: Functional biogeography in Japanese cedar

Effects of carbon nanofibers on hydration and geopolymerization of low and high-calcium geopolymers

This paper discusses the different modifying mechanisms of carbon nanofiber (CNF) on the geopolymers with different calcium contents. First, the rheological and mechanical properties of CNF modified geopolymers with low and high-calcium content are measured. Results show that the modifying effect on rheological properties is more obvious on high-calcium geopolymers. The compressive and flexural strength of low-calcium geopolymers decrease, while the compressive and flexural strength of high-calcium geopolymers significantly improve. Based on XRD, MIP, and SEM analyses, it can be concluded that CNFs help to produce refined hydration products in high-calcium geopolymers, resulting in a denser structure. Promoting hydration can counteract the adverse effect caused by the agglomeration of CNFs. CNFs have a positive effect on high-calcium geopolymers in general. However, hydration reaction rarely happens in the low-calcium geopolymers because of the low calcium content, and XRD results show that CNFs do not significantly promote the geopolymerization reaction. Moreover, the agglomeration of CNFs leads to a decrease in compactness. CNFs negatively affect low-calcium geopolymers. Generally, CNFs can be applied in high-calcium geopolymers to form a denser structure and improve the mechanical properties.

Relación entre la mancha negra extrínseca y la caries dental en una población de Argentina

Many published studies express that the presence of extrinsic black stain on the enamel of tooth surfaces in children and adolescents is associated with less dental caries (CD) activity, this being valid for both primary and permanent dentition.The objective or this researh was to carry out a multifactorial approach to know the relationship between the presence of extrinsic black stain and the presence of caries, in a population of the city of Córdoba, Argentina.Methods. A case-control study (5: 1) was carried out in patients of both sexes from 3 to15 years of age, between the years 2016-2019, who were attended by spontaneous request to the Chair "A" of Pediatric Dentistry, of the Faculty of Dentistry, from the National University of Córdoba (n = 184). All patients underwent a Clinical History. Stimulated saliva was extracted for calcium and phosphate determination and dental biofilm was taken to measure CFU / mL of Streptococcus mutansand Lactobacillus spp.Results. The prevalence of extrinsic black spot was 1.78%. No significant association was found between sex, age and types of dentition between the groups studied. In the problem group, a lower amount of CFU / mL of S. mutans and Lactobacilluss pp was found, a higher concentration of calcium and phosphate and a lower caries index of the primary dentition. Patients with extrinsic black spot had a much lower rate.Conclusions. The extrinsic black spot could be an element of protection against caries, the recommendation for patients who present them would be to remove them from the visible areas and keep them in the rest of the dental elements

Effects of Multi-stage Procurement on the Viability and Function of Human Donor Parathyroid Glands.

Parathyroid allotransplantation is an emerging treatment for severe hypoparathyroidism. Ensuring the viability and functional integrity of donor parathyroid glands following procurement is essential for optimal transplantation outcomes. Cellular viability, calcium-responsive hormone secretion, and gland xenograft survival were assessed in a series of deceased donor parathyroid glands following a two-stage procurement procedure recently developed by our group (en bloc cadaveric dissection with subsequent gland isolation after transport to the laboratory). Parathyroid glands resected in this manner and stored up to 48h in 4°C University of Wisconsin (UW) media retained invitro viability with no induction of hypoxic stress (HIF-1α) or apoptotic (caspase-3) markers. Exvivo storage did not significantly affect parathyroid gland calcium sensing capacity, with comparable calcium EC50 values and suppression of parathyroid hormone secretion at high ambient calcium concentrations. The isolated glands engrafted readily, vascularizing rapidly invivo following transplantation into mice. Parathyroid tissue retains viability, calcium-sensing capacity, and invivo engraftment capability after en bloc cadaveric resection, exvivo dissection, and extended cold storage.