Common variants in CLDN2 and MORC4 genes confer disease susceptibility in patients with chronic pancreatitis

A recent Genome-wide Association Study (GWAS) identified association with variants in X-linked CLDN2 and MORC4 and PRSS1-PRSS2 loci with Chronic Pancreatitis (CP) in North American patients of European ancestry. We selected 9 variants from the reported GWAS and replicated the association with CP in Indian patients by genotyping 1807 unrelated Indians of Indo-European ethnicity, including 519 patients with CP and 1288 controls. The etiology of CP was idiopathic in 83.62% and alcoholic in 16.38% of 519 patients. Our study confirmed a significant association of 2 variants in CLDN2 gene (rs4409525—OR 1.71, P = 1.38 x 10-09; rs12008279—OR 1.56, P = 1.53 x 10-04) and 2 variants in MORC4 gene (rs12688220—OR 1.72, P = 9.20 x 10-09; rs6622126—OR 1.75, P = 4.04x10-05) in Indian patients with CP. We also found significant association at PRSS1-PRSS2 locus (OR 0.60; P = 9.92 x 10-06) and SAMD12-TNFRSF11B (OR 0.49, 95% CI [0.31–0.78], P = 0.0027). A variant in the gene MORC4 (rs12688220) showed significant interaction with alcohol (OR for homozygous and heterozygous risk allele -14.62 and 1.51 respectively, P = 0.0068) suggesting gene-environment interaction. A combined analysis of the genes CLDN2 and MORC4 based on an effective risk allele score revealed a higher percentage of individuals homozygous for the risk allele in CP cases with 5.09 fold enhanced risk in individuals with 7 or more effective risk alleles compared with individuals with 3 or less risk alleles (P = 1.88 x 10-14). Genetic variants in CLDN2 and MORC4 genes were associated with CP in Indian patients

Synergistic delamination toughening of composites using multi-scale carbon reinforcements

Multi-scale toughening is a key strategy employed by biological systems, made of intrinsically brittle constituents, to achieve high damage tolerance. This paper presents an investigation of the synergistic enhancements to the mode I interlaminar fracture toughness of fibre-polymer composite laminates using multi-scale carbon reinforcements. By combining carbon nanofibres (CNFs) dispersed in the matrix and z-pins in the laminate thickness at various contents, an extra mechanism of energy dissipation occurs. This additional mechanism synergistically improves the laminate's resistance to delamination growth under mode I loading. Addition of the nanofibres in the matrix increases the interfacial strength and frictional energy dissipation during z-pin pull-out, thus generating a greater-than-additive toughening effect that would not have existed should either the nanofibres or the z-pins been deployed alone. The results reveal that the magnitude of the synergistic toughening effect was dependent on the volume fraction and combinations of CNFs and z-pins used; where synergy values ranged between 24 and 69% over the expected additive toughness value. A numerical model was developed to successfully predict the crack growth resistance and the synergistic toughening effect with filler content of the multi-scale composites

Temperature dependent structural, vibrational and magnetic properties of K<SUB>3</SUB>Gd<SUB>5</SUB>(PO<SUB>4</SUB>)<SUB>6</SUB>

Herein we report the evolution of the crystal structure of K<SUB>3</SUB>Gd<SUB>5</SUB>(PO<SUB>4</SUB>)<SUB>6</SUB> in the temperature range from 20 K to 1073 K, as observed from variable temperature X-ray diffraction and Raman spectroscopic studies. K<SUB>3</SUB>Gd<SUB>5</SUB>(PO<SUB>4</SUB>)<SUB>6</SUB> has an open tunnel containing a three dimensional structure built by [Gd<SUB>5</SUB>(PO<SUB>4</SUB>)<SUB>6</SUB>]<SUP>3−</SUP> ions which in turn are formed of PO<SUB>4</SUB> tetrahedra and GdO<SUB>n</SUB> (n = 8 and 9) polyhedra. The empty tunnels in the structure are occupied by K+ ions and maintain charge neutrality in the lattice. Evolution of unit cell parameters with temperature shows a systematic increase with temperature. The average axial thermal expansion coefficients between 20 K and 1073 K are: α<SUB>a</SUB> = 10.6 × 10<SUP>−6</SUP> K<SUP>−1</SUP>, α<SUB>b</SUB> = 5.5 × 10<SUP>−6</SUP> K<SUP>−1</SUP> and α<SUB>c</SUB> = 16.4 × 10<SUP>−6</SUP> K<SUP>−1</SUP>. The evolution of distortion indices of the various coordination polyhedra with temperature indicates a gradual decrease with increasing temperature, while those of Gd2O<SUB>9</SUB> and K2O<SUB>8</SUB> polyhedra show opposite trends. The overall anisotropy of the lattice thermal expansion is found to be controlled largely by the effect of temperature on GdO<SUB>n</SUB> polyhedra and their linkages. Temperature dependent Raman spectroscopic studies indicated that the intensities and wavenumbers of most of the Raman modes decrease continuously with increasing temperature. Anharmonic analyses of Raman modes indicated that the lattice, rigid translation and librational modes have larger contributions towards thermal expansion of K<SUB>3</SUB>Gd<SUB>5</SUB>(PO<SUB>4</SUB>)<SUB>6</SUB> compared to high frequency internal modes. The temperature and field dependent magnetic measurements indicated no long range ordering down to 2 K and the observed effective magnetic moment per Gd<SUP>3+</SUP> ion and the Weiss constant are 7.91 μ<SUB>B</SUB> and 0.38 K, respectively

Structural and Thermal Properties of BaTe₂O₆: Combined Variable-Temperature Synchrotron X‑ray Diffraction, Raman Spectroscopy, and ab Initio Calculations

Variable-temperature Raman spectroscopic and synchrotron X-ray diffraction studies were performed on BaTe₂O₆ (orthorhombic, space group: <i>Cmcm</i>), a mixed-valence tellurium compound with a layered structure, to understand structural stability and anharmonicity of phonons. The structural and vibrational studies indicate no phase transition in it over a wider range of temperature (20 to 853 K). The structure shows anisotropic expansion with coefficients of thermal expansion in the order α_b ≫ α_a > α_c, which was attributed to the anisotropy in bonding and structure of BaTe₂O₆. Temperature evolution of Raman modes of BaTe₂O₆ indicated a smooth decreasing trend in mode frequencies with increasing temperature, while the full width at half-maximum (fwhm) of all modes systematically increases due to a rise in phonon scattering processes. With the use of our earlier reported isothermal mode Grüneisen parameters, thermal properties such as thermal expansion coefficient and molar specific heat are calculated. The pure anharmonic (explicit) and quasiharmonic (implicit) contribution to the total anharmonicity is delineated and compared. The temperature dependence of phonon mode frequencies and their fwhm values are analyzed by anharmonicity models, and the dominating anharmonic phonon scattering mechanism is concluded in BaTe₂O₆. In addition to the lattice modes, several external modes of TeO_<i>n</i> (<i>n</i> = 5, 6) are found to be strongly anharmonic. The ab initio electronic structure calculations indicated BaTe₂O₆ is a direct band gap semiconductor with gap energy of ∼2.1 eV. Oxygen orbitals, namely, O-2p states in the valence band maximum and the sp-hybridized states in the conduction band minimum, are mainly involved in the electronic transitions. In addition a number of electronic transitions are predicted by the electronic structure calculations. Experimental photoluminescence results are adequately explained by the ab initio calculations. Further details of the structural and vibrational properties are explained in the manuscript

Phase Transformation, Vibrational and Electronic Properties of K₂Ce(PO₄)₂: A Combined Experimental and Theoretical Study

Herein we report the high-temperature crystal chemistry of K₂Ce­(PO₄)₂ as observed from a joint in situ variable-temperature X-ray diffraction (XRD) and Raman spectroscopy as well as ab initio density functional theory (DFT) calculations. These studies revealed that the ambient-temperature monoclinic (<i>P</i>2₁<i>/n</i>) phase reversibly transforms to a tetragonal (<i>I</i>4₁<i>/amd</i>) structure at higher temperature. Also, from the experimental and theoretical calculations, a possible existence of an orthorhombic (<i>Imma</i>) structure with almost zero orthorhombicity is predicted which is closely related to tetragonal K₂Ce­(PO₄)₂. The high-temperature tetragonal phase reverts back to ambient monoclinic phase at much lower temperature in the cooling cycle compared to that observed at the heating cycle. XRD studies revealed the transition is accompanied by volume expansion of about 14.4%. The lower packing density of the high-temperature phase is reflected in its significantly lower thermal expansion coefficient (α_V = 3.83 × 10^–6 K^–1) compared to that in ambient monoclinic phase (α_V = 41.30 × 10^–6 K^–1). The coexistences of low- and high-temperature phases, large volume discontinuity in transition, and large hysteresis of transition temperature in heating and cooling cycles, as well as drastically different structural arrangement are in accordance with the first-order reconstructive nature of the transition. Temperature-dependent Raman spectra indicate significant changes around 783 K attributable to the phase transition. In situ low-temperature XRD, neutron diffraction, and Raman spectroscopic studies revealed no structural transition below ambient temperature. Raman mode frequencies, temperature coefficients, and reduced temperature coefficients for both monoclinic and tetragonal phases of K₂Ce­(PO₄)₂ have been obtained. Several lattice and external modes of rigid PO₄ units are found to be strongly anharmonic. The observed phase transition and structures as well as vibrational properties of both ambient- and high-temperature phases were complimented by DFT calculations. The optical absorption studies on monoclinic phase indicated a band gap of about 2.46 eV. The electronic structure calculations on ambient-temperature monoclinic and high-temperature phases were also carried out

Phase Transformation, Vibrational and Electronic Properties of K₂Ce(PO₄)₂: A Combined Experimental and Theoretical Study

Herein we report the high-temperature crystal chemistry of K₂Ce­(PO₄)₂ as observed from a joint in situ variable-temperature X-ray diffraction (XRD) and Raman spectroscopy as well as ab initio density functional theory (DFT) calculations. These studies revealed that the ambient-temperature monoclinic (<i>P</i>2₁<i>/n</i>) phase reversibly transforms to a tetragonal (<i>I</i>4₁<i>/amd</i>) structure at higher temperature. Also, from the experimental and theoretical calculations, a possible existence of an orthorhombic (<i>Imma</i>) structure with almost zero orthorhombicity is predicted which is closely related to tetragonal K₂Ce­(PO₄)₂. The high-temperature tetragonal phase reverts back to ambient monoclinic phase at much lower temperature in the cooling cycle compared to that observed at the heating cycle. XRD studies revealed the transition is accompanied by volume expansion of about 14.4%. The lower packing density of the high-temperature phase is reflected in its significantly lower thermal expansion coefficient (α_V = 3.83 × 10^–6 K^–1) compared to that in ambient monoclinic phase (α_V = 41.30 × 10^–6 K^–1). The coexistences of low- and high-temperature phases, large volume discontinuity in transition, and large hysteresis of transition temperature in heating and cooling cycles, as well as drastically different structural arrangement are in accordance with the first-order reconstructive nature of the transition. Temperature-dependent Raman spectra indicate significant changes around 783 K attributable to the phase transition. In situ low-temperature XRD, neutron diffraction, and Raman spectroscopic studies revealed no structural transition below ambient temperature. Raman mode frequencies, temperature coefficients, and reduced temperature coefficients for both monoclinic and tetragonal phases of K₂Ce­(PO₄)₂ have been obtained. Several lattice and external modes of rigid PO₄ units are found to be strongly anharmonic. The observed phase transition and structures as well as vibrational properties of both ambient- and high-temperature phases were complimented by DFT calculations. The optical absorption studies on monoclinic phase indicated a band gap of about 2.46 eV. The electronic structure calculations on ambient-temperature monoclinic and high-temperature phases were also carried out

Phase Transformation, Vibrational and Electronic Properties of K₂Ce(PO₄)₂: A Combined Experimental and Theoretical Study

Herein we report the high-temperature crystal chemistry of K₂Ce­(PO₄)₂ as observed from a joint in situ variable-temperature X-ray diffraction (XRD) and Raman spectroscopy as well as ab initio density functional theory (DFT) calculations. These studies revealed that the ambient-temperature monoclinic (<i>P</i>2₁<i>/n</i>) phase reversibly transforms to a tetragonal (<i>I</i>4₁<i>/amd</i>) structure at higher temperature. Also, from the experimental and theoretical calculations, a possible existence of an orthorhombic (<i>Imma</i>) structure with almost zero orthorhombicity is predicted which is closely related to tetragonal K₂Ce­(PO₄)₂. The high-temperature tetragonal phase reverts back to ambient monoclinic phase at much lower temperature in the cooling cycle compared to that observed at the heating cycle. XRD studies revealed the transition is accompanied by volume expansion of about 14.4%. The lower packing density of the high-temperature phase is reflected in its significantly lower thermal expansion coefficient (α_V = 3.83 × 10^–6 K^–1) compared to that in ambient monoclinic phase (α_V = 41.30 × 10^–6 K^–1). The coexistences of low- and high-temperature phases, large volume discontinuity in transition, and large hysteresis of transition temperature in heating and cooling cycles, as well as drastically different structural arrangement are in accordance with the first-order reconstructive nature of the transition. Temperature-dependent Raman spectra indicate significant changes around 783 K attributable to the phase transition. In situ low-temperature XRD, neutron diffraction, and Raman spectroscopic studies revealed no structural transition below ambient temperature. Raman mode frequencies, temperature coefficients, and reduced temperature coefficients for both monoclinic and tetragonal phases of K₂Ce­(PO₄)₂ have been obtained. Several lattice and external modes of rigid PO₄ units are found to be strongly anharmonic. The observed phase transition and structures as well as vibrational properties of both ambient- and high-temperature phases were complimented by DFT calculations. The optical absorption studies on monoclinic phase indicated a band gap of about 2.46 eV. The electronic structure calculations on ambient-temperature monoclinic and high-temperature phases were also carried out