A randomized, controlled trial examining quarter-level somatic cell count and culture-based selective dry cow therapy against blanket dry cow therapy on early-lactation production outcomes

The objective of this study was to determine quarters requiring antimicrobial treatment using either a benchtop somatic cell counter (S-SDCT) or culture with gram-positive selective media (C-SDCT) and compare outcomes in these cows to those receiving blanket dry cow therapy (BDCT) in a randomized, controlled trial. Two novel methods of identifying cows with intramammary infections followed by selective antimicrobial treatment were evaluated at a commercial dairy farm to determine their usefulness in decreasing antibiotic usage during the dry period without significant detrimental effects on milk quality and production. Cows (n = 840) were randomly allocated to one of 3 groups (BDCT, C-SDCT, S-SDCT) the day before dry-off and quarter-level milk samples (QLMS) were collected. The QLMS from cows in the S-SDCT group were evaluated using the cell counter and quarters were treated if somatic cell count (SCC) was ≥200,000 cells/mL, while QLMS from cows in the C-SDCT group were cultured and quarters were treated if the culture showed growth. All cows in the BDCT received antimicrobial therapy and all cows received an internal teat sealant regardless of treatment group. Outcomes measured were first and second DHIA test somatic cell count, milk production through 60 d in milk, cows leaving the farm, clinical mastitis, and bacteriologic new infections in a subset of quarters. Cows in both SDCT groups had fewer antimicrobial treatments than cows in the BDCT group as was expected, and cows in the C-SDCT group had fewer treatments than those in the S-SDCT group. Cows in both SDCT groups had higher linear score at the first DHIA test (BDCT: 1.8, S-SDCT: 2.2, C-SDCT: 2.2), however there were no other differences between groups regarding any other outcomes measured. While antimicrobial use was significantly reduced, farms should use caution in adopting the benchtop analyzer and the selective media described in this study as ways to identify infected cows for dry cow therapy as they may result in increased linear score early in lactation.

Assessment of maxillary sinus fluid volume for postmortem diagnosis of drowning

INTRODUCTION

Drowning is a comprehensive and exclusive diagnosis at autopsy. Autopsy findings such as pleural effusion and waterlogged lungs contribute to the diagnosis. Herein, we aim to reveal the practical usefulness and postmortem changes of the maxillary sinus fluid volume to diagnose drowning.

METHODS

We evaluated 52 drowning and 59 nondrowning cases. The maxillary sinus fluid volume was measured using a computed tomography (CT) scan, and pleural effusion volume and lung weight were manually measured at autopsy. The utility of these three indices for diagnosing drowning and its postmortem changes was evaluated.

RESULTS

The maxillary sinus fluid volume was significantly higher in drowning cases than in other external causes and cardiovascular death cases. Receiver operating characteristic curve analysis revealed that a total maxillary sinus fluid volume >1.04 mL more usefully indicated drowning (odds ratio, 8.19) than a total pleural effusion volume >175 mL (odds ratio, 7.23) and a total lung weight >829 g (odds ratio, 2.29). The combination of maxillary sinus fluid volume and pleural effusion volume more effectively predicted drowning than one index alone. Moreover, the maxillary sinus fluid volume was less influenced by the postmortem interval than the other two indices up to a week after death.

CONCLUSION

Maxillary sinus fluid volume can be more useful than pleural effusion volume and lung weight with higher sensitivity and odds ratio for diagnosing drowning.

IMPLICATIONS FOR PRACTICE

Fluid accumulation in both the maxillary sinuses strongly predicts drowning in the postmortem imaging.

Comparison of an image cytometry somatic cell count analyzer to a flow cytometry analyzer

The objective of this study was to evaluate the performance of a small footprint benchtop somatic cell counter based on image cytometry (LactiCyte HD; Page and Pedersen International Ltd., Hopkinton, MA) against a flow cytometer employed at a regional dairy herd improvement (DHI) laboratory. Milk samples collected during monthly DHI testing were split into 2 samples. One sample was evaluated using flow cytometry (Bentley SomaCount FCM; Bentley Instruments, Chaska, MN) at the regional DHI laboratory, whereas the other was evaluated using image cytometry at 2 different image levels (full number of images, 16 pictures per slide; half number of images, 8 pictures per slide). Mean bias of the image cytometer at 16 images was -15,500 cells/mL, whereas at 8 images the bias was 21,800 cells/mL. When considering only cell counts ≤400,000 cells per mL, the bias for both imaging resolutions was positive, meaning the image cytometer read higher than the flow cytometer. Both imaging resolutions (16 and 8) had a concordance correlation coefficient greater than 0.95. Considering ≥200,000 cells/mL to be indicative of subclinical mammary gland infection, the sensitivity and specificity of the image cytometer at 16 images were 92.0% and 91.7%, whereas the sensitivity and specificity of the analyzer at 8 images were 92.0% and 85.7%, respectively. Method precision (repeatability; coefficients of variation) were calculated at 3 different somatic cell counts (100,000, 200,000, and 400,000 cells/mL) where each sample was run repeatedly 12 times. When analyzed at the full number of images the coefficients of variation were 16.9%, 11.7%, and 10.9% for 100,000, 200,000, and 400,000 cells/mL, respectively. Analysis at half the number of images resulted in coefficients of variation of 18.9%, 24.8%, and 8.7% for 100,000, 200,000, and 400,000 cells/mL. We conclude that the image cytometer is an acceptable somatic cell count analyzer for on-farm use for applications such as screening cows for microbiological testing, and that precision is superior when the analysis is performed at the full number of images allowed by the instrument.

Estimation of brain natriuretic peptide values from N-terminal pro brain natriuretic peptide levels and other factors

Funding Acknowledgements

Type of funding sources: None.

Backgrounds

Both brain natriuretic peptide (BNP) and N-terminal proBNP (NT-pro BNP) are established biomarkers that are necessary in the diagnosis and management of heart failure (HF). Recently with the introduction of angiotensin receptor-neprilysin inhibitor in the treatment of HF, the course of HF is now assessed using NT-ProBNP levels1). However, it is difficult to infer BNP concentration from NT-proBNP levels for a physician who is familiar with BNP. Generally, simultaneous measurement of BNP and NT-proBNP is not permitted in medical insurance.

Purpose

To estimate BNP concentration from NT-proBNP levels and other factors as an equivalent prognostic strength compared to the actual BNP concentration.

Methods

From August 2021 to October 2021, we measured BNP and NT-proBNP levels of patients who were known or suspected to have HF (n=200). We created a formula for estimating BNP concentration from the data of NT-proBNP, age, body mass index (BMI), white cell counts, hemoglobin (Hb), estimated glemerular filtration rate) (eGFR) and C-reactive protein (CRP) using multivariate analysis.

Results

Patients’ background were as follows: age 66.4±23.6 years, male /female : 112/88 , BMI: 23.1±5.2 kg/m2, Hb level: 12.3±2.2 g/dL, albmine level: 3.7±0.7 g/dL, eGFR level: 63.3±27.0 mL/min/1.73m², CRP level; 1.80±4.67 mg/dL, BNP level: 103.3±207.9 pg/mL, NT-proBNP level: 1,505.1±3,479.6 pg/mL (mean ± SD). There was a strong correlation between BNP concentration and NT-proBNP level when using actual measured values (r= 0.84) and when using log-transformed values (r=0.92) in these patients.Using multiple regression analysis, we created an equation that estimated

LogBNP=-0.864+0.734×LogNT-proBNP+0.005×age-0.003×eGFR-0.009×BMI+0.016×CRP (R²=0.89).

Conclusion

This equation will be useful, especially for a physician who is not familiar with NT-proBNP. Testing BNP concentrations were reliably estimated from an equation featuring NT-proBNP, eGFR, age, BMI and CRP2),3),4).

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star-black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1 - 1 + 12 ( 10 - 10 + 52 ) for binary neutron star mergers, of 0 - 0 + 19 ( 1 - 1 + 91 ) for neutron star-black hole mergers, and 17 - 11 + 22 ( 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.

P1547 Left ventricular papillary muscle strain as an indicator of hypertrophic cardiomyopathy

Results

Among the 42 patients, 22 (52%) and 17 (40%) had hypertension and HCM, respectively. We measured the strength of linear associations among paired variables (LV-PMS, age, EF, e’, s’, E/e’, E/A, LAV-I and GLS) using Pearson product-moment correlation coefficients.

Age (r = 0.64), e’ (r = -0.76), s’ (r = -0.61), LAV-I (r = 0.61) and GLS (r = 0.57; all p < 0.001), as well as E/e’ (r = 0.44, p < 0.05) significantly correlated in patients without HCM, whereas only GLS correlated in patients with HCM (r = 0.723, p < 0.001).

One-way analyses of variance showed that LV-PMS values significantly differed only among patients without HCM when categorized according to age < 50, ≥ 50 < 75 and > 75 years (p < 0.001), whereas these values significantly differed in all patients (p < 0.05) when categorized according to GLS < -20%, ≥ -20 to < -15% and > -15%.

Conclusions

We found that LV-PMS correlated with five factors including age in patients without HCM, but only with GLS in those with HCM. Despite the small study cohort, we considered that LV-PMS and GLS would be useful for evaluating left ventricular function in patients with HCM.

Stromal-type Nephroblastoma with or without Anaplasia in Two Hedgehogs (Atelerix albiventris)

We describe the clinical and histological characteristics of stromal-type nephroblastomas that developed in two hedgehogs (Atelerix albiventris). In case 1, the tumour was composed of a proliferation of anaplastic stromal cells with ductal structures resembling the epithelium of nephroblastoma. In case 2, spindle-shaped cells that were somewhat larger than nephroblasts were frequently seen surrounding the cell cluster, and there was proliferation of stromal cells with collagen fibres at the periphery. Immunohistochemically, the tumour cells labelled weakly to strongly for the nephroblast marker Wilms' tumour-1 and were positive for Ki67 with rates of 5% and 10% for cases 1 and 2, respectively. Based on the above, the diagnosis was of stromal-type nephroblastoma with anaplasia in case 1 and without anaplasia in case 2. Our findings suggest that stromal-type nephroblastomas arise in adult hedgehogs and are clinically benign, and that histological anaplasia does not affect the prognosis.

Basal Cell Adenoma of the Salivary Gland and Possible Recurrence as Basal Cell Adenocarcinoma in a Black-tailed Prairie Dog (Cynomys ludovicianus)

We describe a black-tailed prairie dog (Cynomys ludovicianus) with a benign biphasic nodular tumour that recurred as a malignant biphasic tumour at the same site 2 years after resection. Both tumours were biphasic with regard to the glandular epithelium and basal cells and contained little of the mucus, cartilage or fibrous tissue that characterize pleomorphic adenoma and carcinoma ex-pleomorphic adenoma. Both the first and second tumours exhibited histopathological features similar to those exhibited by human basal cell adenoma and adenocarcinoma, respectively. Both were resected and the animal was alive with no recurrence or metastasis at the time of writing, 9 months after the second surgery.

Strange metal from a frustration-driven charge order instability

Interparticle interactions are self-conflicting rather than cooperative on particular lattices. When such geometrical frustration occurs, charge ordering (CO) can be destabilized into non-trivial charge states such as the recently observed charge glass (CG). A more extreme case is the frustration-induced quantum melting of the CO that has been theoretically proposed. Here, we report d.c. charge transport and noise spectroscopy measurements for a triangular-lattice organic conductor situated close to the CO or CG. Our experiments demonstrate that these materials can host a strange metal with unusual charge dynamics, which we attribute to frustration-induced fluctuations of the CO or CG. Our results also show that the anomalous charge fluctuations can freeze into an insulating state when uniaxial stress is applied, which reduces the geometrical frustration. The present observations suggest the existence of the frustration-induced quantum melting of charges analogous to spin liquids.

Quantum-disordered state of magnetic and electric dipoles in an organic Mott system

Strongly enhanced quantum fluctuations often lead to a rich variety of quantum-disordered states. Developing approaches to enhance quantum fluctuations may open paths to realize even more fascinating quantum states. Here, we demonstrate that a coupling of localized spins with the zero-point motion of hydrogen atoms, that is, proton fluctuations in a hydrogen-bonded organic Mott insulator provides a different class of quantum spin liquids (QSLs). We find that divergent dielectric behavior associated with the approach to hydrogen-bond order is suppressed by the quantum proton fluctuations, resulting in a quantum paraelectric (QPE) state. Furthermore, our thermal-transport measurements reveal that a QSL state with gapless spin excitations rapidly emerges upon entering the QPE state. These findings indicate that the quantum proton fluctuations give rise to a QSL—a quantum-disordered state of magnetic and electric dipoles—through the coupling between the electron and proton degrees of freedom.

The organic material κ-H₃(Cat-EDT-TTF)₂ has been suggested to exhibit a quantum spin liquid phase in which quantum fluctuations prevent the formation of magnetic order. Here, the authors show that this may be a result of fluctuations of hydrogen atoms, rather than more conventional geometric frustration.

Crystallization and vitrification of electrons in a glass-forming charge liquid

Charge ordering (CO) is a phenomenon in which electrons in solids crystallize into a periodic pattern of charge-rich and charge-poor sites owing to strong electron correlations. This usually results in long-range order. In geometrically frustrated systems, however, a glassy electronic state without long-range CO has been observed. We found that a charge-ordered organic material with an isosceles triangular lattice shows charge dynamics associated with crystallization and vitrification of electrons, which can be understood in the context of an energy landscape arising from the degeneracy of various CO patterns. The dynamics suggest that the same nucleation and growth processes that characterize conventional glass-forming liquids guide the crystallization of electrons. These similarities may provide insight into our understanding of the liquid-glass transition.

Prevention of steroid-induced osteonecrosis of femoral head in systemic lupus erythematosus by anti-coagulant

Although osteonecrosis of femoral head (ONF) is one of the serious complications in systemic lupus erythematosus (SLE) associated with corticosteroid therapy, there has been few trials of prevention of ONF described. We aimed to prevent ONF in steroid-treated SLE patients using anticoagulant, warfarin, conducting a multicenter prospective study. Sixty newly diagnosed SLE patients requiring 40 mg/day or more prednisolone were alternately assigned to either of two groups; a warfarin group and a control one. Warfarin (1 ∼ 5 mg/day) was started together with the beginning of steroid therapy and continued at least for three months. Patients were observed for the development of silent ONF by magnetic resonance imaging (MRI) and symptomatic ONF by plain radiography for over five years. The warfarin group consisted of 31 patients (62 hips) and the control one 29 patients (58 hips). Silent ONF developed in 13 hips (21%) and 19 hips (33%) in the warfarin group and the control group, respectively ( P = 0.13). On the other hand, warfarin tended to prevent symptomatic ONF; only three hips of 62 (4.8%) in the warfarin group and eight hips of 58 (14%) in the control group ( P = 0.08) developed silent ONF. It was also found that silent ONF developed, if it did, very early; within three months in 16 of 18 patients (89%). Among risk factors for silent ONF, steroid pulse therapy was most outstanding and it seemed to overcome the effect of warfarin. Taken together, for the time being, anticoagulant therapy, if not significantly sufficient, may be of use for the prevention of steroid-induced ONF in SLE. We consider that this study added to important evidence for the pathogenesis and prevention of ONF.

Very early development of steroid-associated osteonecrosis of femoral head in systemic lupus erythematosus: prospective study by MRI

The objective of this study was to define prospectively the early development of corticosteroid-induced osteonecrosis of femoral head (ONF) in patients with systemic lupus erythematosus (SLE) and to identify the association of initial steroid treatment with the development of early (silent) ONF. Forty-five patients who were newly diagnosed as having SLE and required 40 mg/day or more prednisolone were enrolled. To detect silent ONF, examinations using magnetic resonance imaging (MRI) were done three months after starting steroid therapy, followed by every year’s MRI and plain radiography for over five years. Clinical and laboratory data were compared between silent ONF and non-ONF groups. Of 45 patients, 15 (33%) developed silent ONF and five (11%) symptomatic ONF. It was of interest that MRI detected silent ONF very early (by three months) in 14 patients (93%). It should be noted that pulse therapy with 1000 mg/day methylprednisolone was found to be done very frequently (13 of 15, 87%) in the silent ONF group compared to non-ONF group (11 of 30, 37%) (P, 0.01) although other clinical features were not significantly different between both groups. High dose corticosteroids caused elevation of serum levels of total cholesterol, albumin, and leukocyte count in most of patients. The degree of elevation of those parameters at one or three months was more prominent in the silent ONF group. In particular, the change ratio of total cholesterol at one month was outstanding in the silent ONF group compared to non-ONF group (0.551 versus 0.374, P, 0.05). In conclusion, pathological ONF develops very early in one-third of SLE patients who received high dose corticosteroids and steroid pulse therapy could be a significant risk factor. An abrupt elevation of serum total cholesterol and/or sensitivity to steroids seem to be associated with the pathogenesis of ONF.

Catastrophic antiphospholipid syndrome associated with malignancies (case report and review of the literature)

We describe a 58-year old female patient with rapid development of arterial and venous thromboembolisms, including deep vein thrombosis (DVT) in the lower limbs, recurrent cerebral infarctions and bilateral pulmonary emboli. Her laboratory data on admission showed positive anticardiolipin antibody of IgG isotype (IgG aCL) and positive anti-β2 glycoprotein-I antibody of IgG isotype (IgG aβ2-GPI), and decreased protein C activity and protein S antigen. Systemic examinations revealed the presence of an ovarian cancer. Surgical resection was attempted, but her cancer infiltrated the pelvic wall and could not be resected. Despite treatment with unfractionated heparin followed by warfarin, she died due to recurrent episodes of cerebral infarction.

This case was considered as probable catastrophic antiphospholipid syndrome (CAPS), which might be associated with ovarian cancer. Known as Trousseau's syndrome, arterial and, more commonly, venous thrombosis is a frequent complication of cancer and sometimes a harbinger of occult cancer. Our case indicates that there is an overlap between antiphospholipid syndrome (APS) and Trousseau's syndrome. It is important to bear in mind that a thrombotic event associated with cancer can be the first manifestation of CAPS.

Case Study of Volatile Organic Compounds in Indoor Air of a House before and after Repair where Sick Building Syndrome Occurred

A housewife in her late thirties, mother of two children, had an indefinite complaint about the indoor air quality of her house. Inspectors from a public health center treating the housewife's complaint quantified formaldehyde (FA) in high concentration exceeding Japanese national guideline of FA in some rooms of the house. We also determined FA and total volatile organic compounds (TVOCs) in higher concentrations more than the national guidelines. Remodeling of the house was performed to improve the air quality as follows. Vinyl wallpaper was exchanged to plant made paper, plywood made doors were exchanged to pure wood made doors, plywood stairs were covered with plant cork and so on. After remodeling the house, we measured the concentrations of FA and TVOCs again. The concentrations of the chemicals in the indoor air decreased which approve effectiveness of the remodeling. Moreover complaints of the housewife lessened. This also proved the effectiveness of the remodeling. Four years after the inspection, we visited the house again and found that the concentration of FA in the house was still lower than that of national guideline. The housewife was evaluated in a good healthy condition by her answers to our questions related to indoor air quality, daily life, physical condition, and so on.

Occupational Allergic Contact Dermatitis from Mioga (Zingiber Mioga Rosc.) in Greenhouse Cultivators

Mioga ( Zingiber mioga Rosc.) is a member of the ginger family (Zingiberaceae), which is native to tropical Asia. In Japan, the young flower buds are used as a spice, and hand dermatitis suspected as being an allergy to mioga has been recognized in mioga greenhouse cultivators. To investigate the extent of the problems and the causes of dermatitis, 20 householders cultivating mioga in their greenhouses were asked to participate in a questionnaire study. Consecutive patch tests were performed on some subjects with dermatitis. Self-reported questionnaires were distributed to the main cultivator in each household who attended a lecture of mioga cultivation methods held at an agriculture cooperative association in the area. Some subjects who answered as presenting or having had hand dermatitis were patch tested for mioga (as is), four kinds of mioga extracts, and three kinds of natural rubber gloves. Results: 35 cultivators from 16 households answered the questionnaire. Eight of the 35 subjects (22.9%) answered that they had experienced hand dermatitis since they started mioga cultivation. Four of the 8 subjects were patch tested. Two of the 4 subjects showed allergic reactions to mioga (as is) and the extracts. The other two cases showed irritation to mioga (as is). The first two cases also showed allergic reactions to natural rubber gloves. To our knowledge, there is no previous report of allergic contact dermatitis from mioga.

Subjective Symptoms of Medical Students Exposed to Formaldehyde during a Gross Anatomy Dissection Course

The purpose of this study is to investigate the safety of and to try to find the best plan to cope with exposure to FA for students during a gross anatomy dissection course. The FA exposure level and subjective symptoms was estimated. The relationship between exposure to FA and subjective symptoms of irritation were discussed for times; before, in the beginning period, in the middle period, and upon completion of the Anatomy Dissection Course. The geometric means of FA concentration were 32.7 ug/m3 (before), 891.3 ug/m3 (beginning), 763.3 ug/m3 (middle), and 238.9 ug/m3 (completion), respectively. Among them, FA-related symptoms were observed in 61.1%; 28.0% fell strong stress during the course, and 27.4% complained that their normal life situation was affected. Our results indicate that such subjective symptoms during the anatomy dissection course were related to the period spent in the anatomy dissection room. Our study suggests that shortening the time of each anatomy dissection practical class and reduction of the number of cadaver tables could help to reduce symptoms.

The main chemical properties of hot and cold mineral waters in Bayankhongor, Mongolia

In the current study, hot and cold mineral springs and sub mineral waters in the Bayankhongor province were examined for their chemical characteristics and identified cold mineral waters classification according to mineral water classification of Mongolia. The hot spring waters belong to Na+-HCO3- and Na+-SO42- types. The cold mineral spring of Lkham belongs to Ca2+-HCO3- type. All sub mineral waters are generally located in the two areas (northern part or mountain forest area and the southern part or Gobi desert area). TDS concentrations of cold springs of the southern part in the study area were higher than northern part’s cold springs. The total dissolved silica content of cold spring was ranged from 4.5mg/L to 26 mg/L which did not correspond to requirements of mineral water standard of Mongolia. Thus, these cold springs are belonging to sub mineral water classification. The sub mineral waters were characterized into four types such as a Ca2+-SO42-, Na+-SO42-, Na+-HCO3 and Ca2+ - HCO3 by their chemical composition in the study area. The values for the quartz, chalcedony geothermometer and the Na/K geothermometer were quite different. The silica-enthalpy mixing model predicts a subsurface reservoir temperature between 124 and 197°C and most of the hot waters have been  probably mixed with cold water. The result shows that an averaged value of calculated temperature ranges from 77°C to 119°C which indicates that studied area has low temperature geothermal resources. DOI: http://doi.dx.org/10.5564/mjc.v15i0.324 Mongolian Journal of Chemistry 15 (41), 2014, p56-62