Do thermodynamically stable rigid solids exist?

Customarily, crystalline solids are defined to be {\em rigid} since they resist changes of shape determined by their boundaries. However, rigid solids cannot exist in the thermodynamic limit where boundaries become irrelevant. Particles in the solid may rearrange to adjust to shape changes eliminating stress without destroying crystalline order. Rigidity is therefore valid only in the {\em metastable} state that emerges because these particle rearrangements in response to a deformation, or strain, are associated with slow collective processes. Here, we show that a thermodynamic collective variable may be used to quantify particle rearrangements that occur as a solid is deformed at zero strain rate. Advanced Monte Carlo simulation techniques are then employed to obtain the equilibrium free energy as a function of this variable. Our results lead to a new view on rigidity: While at zero strain a rigid crystal coexists with one that responds to infinitesimal strain by rearranging particles and expelling stress, at finite strain the rigid crystal is metastable, associated with a free energy barrier that decreases with increasing strain. The rigid phase becomes thermodynamically stable by switching on an external field, which penalises particle rearrangements. This produces a line of first-order phase transitions in the field - strain plane that intersects the origin. Failure of a solid once strained beyond its elastic limit is associated with kinetic decay processes of the metastable rigid crystal deformed with a finite strain rate. These processes can be understood in quantitative detail using our computed phase diagram as reference.Comment: 11 pages, 7 figure

Role of inflammation as reflected by serum hsCRP and ferritin level in major depressive disorder

Background: The relationship between depression and inflammation has been strengthened by different studies for which Immune Cytokine Mechanism has been proposed to explain pathogenesis of depression.Methods: The role of inflammation in major depressive disorder (MDD) has been evaluated in this study among 101 patients suffering from MDD along with 106 age and sex matched control subjects. Two well known acute phase reactant proteins namely hsCRP and Ferritin were assayed in all study subjects by Enzyme Immuno Assay method.Results: Concentration of hsCRP in serum was found to be significantly increased in all patients suffering from MDD whereas Ferritin level was found to be significantly decreased in male MDD subjects only (male: 70.6 ng/ml±53.54 ng/ml in MDD vs 100.16 ng/ml±39.93 in controls; female: 38.43 ng/ml±11.2 in MDD vs 39.93 ng/ml±15.0 in controls). There was no significant alteration of the parameters among different grades of MDD. The possibility of these two parameters to be used as biomarkers has also been evaluated by ROC curve.Conclusions: The significant change in hsCRP & Ferritin which is not associated with grade wise alteration suggests that probably inflammation is the early event which causes depression. Therefore no gradual change is observed with increase in severity of the disease. hsCRP can be used as a biomarker of Inflammation in MDD cases

Socio-Demographic and Clinical Profile of Drug Resistant Tuberculosis Patients in a Tertiary Care Centre of Kolkata

Background: Drug resistant tuberculosis is a major public health threat that hinders progress in tuberculosis control worldwide. In 2019, India contributed highest cases of TB (27%) Worldwide. In 2019, 3.3% of new TB cases and 18% of previously treated cases had MDR/RRTB worldwide and India (27%) had the largest share of the global burden. This study was done to find out the sociodemographic and clinical profile of drug resistant TB patients. Methodology: It is an observational descriptive study with cross-sectional design, conducted at the drug resistant tuberculosis centre of R. G. Kar Medical College of Kolkata, West Bengal. Study Population consisted of the patients who were registered for the DR-TB regimen. Study duration was July 2016 –March 2017. Pre-tested, semi-structured schedule was designed to capture their sociodemographic profile, treatment history, clinical findings and available medical records. Data were compiled in MS Excel and analyzed in IBM SPSS 23.0. Results: Out of 159 cases, 27% patients were between 21-30 years. Males were predominant (68.6%). Most patients (56.6%) were underweight (BMI<18.5kg/m2). HIV seropositivity was found in 4 (2.5%) cases. Among all cases, 81.1% had history of taking ATD and 34.4% was cured in previous episode of treatment. The commonest associated comorbidity was DM (15.7%). Rifampicin resistance (93.1%) was most common followed by Isoniazid (8.2%). Pallor was found among 94.3% patients. Most patients had bilateral (62.3%) and moderately extensive (57.2%) lesions in chest x-ray. Conclusion: DR-TB control should focus adequately on younger age group as numbers of resistance is increasing among them. Relapse in previously cured cases was found to be major contributor of DR-TB suspect cases. Though, Rifampicin resistance was so common but prevalence of resistance to 2nd line drugs is still low. Focus should be given on early detection of drug resistance in all TB cases and improvement of nutritional status of the TB patient

Sperm Motility Regulatory Proteins: A Tool to Enhance Sperm Quality

Sperm forward motility is an essential parameter in mammalian fertilization. Studies from our laboratory have identified and characterized a few unique sperm motility regulatory proteins/glycoproteins from the male reproductive fluids and mammalian blood serum. The purified sperm motility-initiating protein (MIP) from caprine epididymal plasma as well as the forward motility-stimulating factor (FMSF) and motility-stimulating protein (MSP) from buffalo and goat serum, respectively, have high efficacy to initiate or increase motility in nonmotile or less motile sperm. Antibody of sperm motility inhibitory factor (MIF-II) has the high potential to enhance sperm vertical velocity and forward motility by increasing intracellular cyclic adenosine monophosphate (cAMP) level. The appearance and disappearance of D-galactose–specific lectin and its receptor along the epididymis has been reported to be involved in motility regulation in spermatozoa. A novel synthetic cryopreservation method and role of lipid to protect membrane damage during cryopreservation have been demonstrated. Motility-promoting proteins may be extremely useful for improving cattle breeding and breeding of endangered species, thereby helping in enhanced production of animal products as well as in the conservation of animals. Isolated proteins and developed cryopreservation technology may also be beneficial in human infertility clinics to increase the chance of fertilization

Focused Cardiac Ultrasound to Guide the Diagnosis of Heart Failure in Pregnant Women in India.

BACKGROUND: Cardiac complications are a leading cause of maternal death. Cardiac imaging with echocardiography is important for prompt diagnosis, but it is not available in many low-resource settings. The aim of this study was to determine whether focused cardiac ultrasound performed by trained obstetricians and interpreted remotely by experts can identify cardiac abnormalities in pregnant women in low-resource settings. METHODS: A cross-sectional study was conducted among 301 pregnant and postpartum women recruited from 10 hospitals across three states in India. Twenty-two obstetricians were trained in image acquisition using a portable cardiac ultrasound device following a simplified protocol adapted from focus-assessed transthoracic echocardiography protocol. It included parasternal long-axis, parasternal short-axis, and apical four-chamber views on two-dimensional and color Doppler. Independent image interpretation was performed remotely by two experts, in the United Kingdom and India, using a standard semiquantitative assessment protocol. Interrater agreement between the experts was examined using Cohen's κ. Diagnostic accuracy of the method was examined in a subsample for whom both focused and conventional scans were available. RESULTS: Cardiac abnormalities identified using the focused method included valvular abnormalities (27%), rheumatic heart disease (6.6%), derangements in left ventricular size (4.7%) and function (22%), atrial dilatation (19.5%), and pericardial effusion (30%). There was substantial agreement on the cardiac parameters between the two experts, ranging from 93.6% (κ = 0.84) for left ventricular ejection fraction to 100% (κ = 1) for valvular disease. Image quality was graded as good in 79% of parasternal long-axis, 77% of parasternal short-axis and 64% of apical four-chamber views. The chance-corrected κ coefficients indicated fair to moderate agreement (κ = 0.28-0.51) for the image quality parameters. There was good agreement on diagnosis between the focused method and standard echocardiography (78% agreement), compared in 36 participants. CONCLUSIONS: The focused method accurately identified cardiac abnormalities in pregnant women and could be used for screening cardiac problems in obstetric settings

Simulace venkovního osvětlení sportovišť pomocí vícečetných optických parametrů metodou t-test

The standard lighting design softwares are essentially calculating tools without any optimizing features. Use of these softwares lead to trial & error based iterative design approach. This however produces a set of interim design solutions consisting of appropriate or inappropriate design cases. In this paper, a statistical method, t-test, is successfully applied on these interim design solutions. Hence the list of Determinant Luminaires (DLs) and corresponding Optimized Aiming Angles (OAAs) are identified to enhance multiple optical parameters for the inappropriate design cases

Combustion synthesis of La0.6Sr0.4CO 0.98Ni0.02O3 cathode and evaluation of its electrical and electrochemical properties for IT-SOFC

Nanocrystalline powder (30-40 nm) of 2 mol% Ni-doped lanthanum strontium cobaltite (La0.6Sr0.4Co0.98Ni0.02O3) was synthesized by combustion technique using glycine as fuel with various combinations of fuel to nitrate ratios. The thermal analysis revealed that the crystallization process is not single step and remained incomplete even up to 700{degree sign}C. In XRD analysis, existence of two minor phases was observed in addition to lanthanum strontium cobaltite phase. One particular synthesis condition i.e., with a slightly fuel excess ratio (0.45) showed highest electrical conductivity of 96 S/cm at 800{degree sign}C in air. For the application as cathode in SOFC, this material was studied in the symmetric cell mode with Gd-doped CeO2 as electrolyte and it showed lowest interfacial polarization resistance of 0.158 •cm2 when sintered at 1000{degree sign}C. Significantly high current density of ~ 3.4 A/cm2 and power density of ~ 2.4 W/cm2 at 800{degree sign}C was obtained with this cathode in anode-supported single cell with doped CeO2 as a buffer layer

Glass-based Sealants for Application in Planar Solid Oxide Fuel Cell Stack

One of the major challenges for the commercialization of planar anode-supported solid oxide fuel cell (SOFC) is the development of suitable high temperature sealant. The sealants must maintain gas-tightness between the anode and the cathode compartments to avoid intermixing of fuel and oxidant at high operating temperature (700 degrees-800 degrees C), be an electrical insulator and chemically non-reactive with the stack components. Due to the high commercial importance of such sealants, very few sealing compositions are available in the open literature and have to be developed by the individual SOFC developer. In this context the present article gives an overview on such sealant development with particular emphasis on glass-ceramics based sealants. Other than glass-based sealants, very recent approaches such as compressive and self healing seals also show some potential as SOFC sealants. The review of literature is followed by description of the progress of work related to,development of glass based sealant at our Institute for application in the developed planar anode-supported SOFC stack. Under this developmental activity, a number of glass systems having SiO(2) and B(2)O(3) as glass formers and BaO, MgO and CaO as the alkaline earth metal oxide content have been investigated and thoroughly characterized. Based on the findings, some of these glasses have been used for making seals between different types of SOFC components, e.g. ferritic stainless steel (Crofer22APU) (metallic interconnect) and 8 mol% yttria-stabilized zirconia (YSZ) (electrolyte) under various combinations, viz. metal-metal, metal-ceramic and ceramic-ceramic. A novel concept of ``bi-layered sealing'' consisting of two different glass compositions having graded CTE values has been implemented for the first time during actual SOFC stack operation. The performance of the developed sealants has been evaluated in several working SOFC short stacks (up to 6-cell) for a maximum period of 20 days. It is observed that the open circuit voltage (OCV) of these stacks is very near to its theoretical value and remains same during the stack testing period and thus ensured the potentiality of the developed sealant for SOFC application

Glass-ceramic sealants for planar IT-SOFC: A bilayered approach for joining electrolyte and metallic interconnect

To develop suitable sealants for planar anode-supported intermediate temperature solid oxide fuel cells (IT-SOFC) operating at around 800 degrees C, several glass-ceramic compositions based on the RO-Al2O3-SiO2 (R=Ba,Ca) system have been prepared and investigated. Thermal, chemical, and electrical properties of the glass ceramics along with crystallization behavior and bonding characteristics of parent glasses with yttria-stabilized zirconia (YSZ) electrolyte and ferritic steel-based interconnect Crofer22APU are studied. The glass transition temperatures (T-g) of the developed glasses are within 600-635 degrees C. By varying the alkaline-earth metal content, the coefficient of thermal expansion (CTE) values can be tailored between that of YSZ and Crofer22APU. Based on the crystallization behavior, a single glass seal having matching CTE with Crofer22APU and a bilayer glass seal having different CTE values within the range of 10-13x10(-6)/K are found to be effective for metal-metal and metal-electrolyte sealing, respectively. The electrical resistivities of the sealants are quite high (rho(800 degrees C)> 10(5) Omega cm), and under sandwiched condition between two metals, the developed glasses are found to maintain this high resistivity even after 100 h of operation. A low helium leak rate value (< 10(-6) Pa m(2) s(-1)) has been observed for most of the developed glasses. (c) 2008 The Electrochemical Society