Silicon Revisited: Understanding Pure Phonon Anharmonicity and the Effects on Thermophysical Properties

Phonons, quantized lattice vibrations, govern most of the thermophysical properties of solid-state materials such that understanding the temperature dependent lattice dynamics is of great technological importance. I performed inelastic neutron scattering measurements at the Spallation Neutron Source on ARCS, a wide-angular chopper spectrometer, to measure phonon dispersions and density of states over a wide range of temperatures. Large phonon anharmonicities manifested by phonon energy shifts and broadenings were observed in both measured phonon dispersions and phonon density of states. The sources of deviations from the simple harmonic model with temperature were elucidated using experimentally assessed lattice dynamics coupled with ab initio methods. Pure anharmonicity dominates the changes in lattice dynamics with temperature and therefore drive the entropy and thermophysical properties of thermal expansion and thermal conductivity. Crystal structure, anharmonicity, and nuclear quantum effects all play important roles in the thermal expansion of silicon, and a simple mechanical explanation is inappropriate. The quantum effect of nuclear vibrations is also expected to be important for thermal expansion of many materials. My experimental techniques capture the linewidth broadenings from phonon anharmonicity needed to calculate thermal conductivity. The methods developed for data reduction on single crystal inelastic neutron scattering data and predicting macroscopic quantities should also be useful for understanding microscopic mechanisms behind thermophysical properties for materials

Heavy quarkonium with finite three momentum near TcT_c

We investigate the non-trivial 3-momentum effects on the masses of heavy quarkonium states that are moving in a hot medium using QCD sum rules. For all charmonium states, we observe a negative mass shift near $T_c$ that is less than 3$\%$ at a momentum of 1$\rm{GeV}$. Specifically, we first investigate the difference between the longitudinal and transverse modes of both $J/\psi$ and $\chi_{c1}$. We find that the transverse mode of the $J/\psi$ experiences larger modification than the longitudinal mode, while the $\chi_{c1}$ has the opposite behavior. By comparing the $\eta_c$ and $\chi_{c0}$, and also the unpolarized $J/\psi$ and $\chi_{c1}$, we recognize that the P-wave particles have stronger momentum dependencies on their masses than the S-wave ones. We also find $\Upsilon$(1S) has negligible 3-momentum dependence compared to the charmonium states, e.g. less than 0.01$\%$ even at 1.4$T_c$ and at a momentum of 4$\rm{GeV}$.Comment: 6 pages, 7 figure

Korean Red Ginseng protects dopaminergic neurons by suppressing the cleavage of p35 to p25 in a Parkinson's disease mouse model

AbstractBackgroundGinseng is known to have antiapoptotic, anti-inflammatory, and antioxidant effects. The present study investigated a possible role of Korean Red Ginseng (KRG) in suppressing dopaminergic neuronal cell death and the cleavage of p35 to p25 in the substantia nigra (SN) and striatum (ST) using a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease mouse model.MethodsTen-week-old male C57BL/6 mice were injected intraperitoneally with 30 mg/kg of MPTP at 24-h intervals for 5 d, and then administered KRG (1 mg/kg, 10 mg/kg, or 100 mg/kg) once a day for 12 consecutive days from the first injection. Pole tests were performed to assess the motor function of the mice, dopaminergic neuronal survival in the SN and ST was evaluated using tyrosine hydroxylase-immunohistochemistry, and the expressions of cyclin-dependent kinase 5 (Cdk5), p35, and p25 in the SN and ST were measured using Western blotting.ResultsMPTP administration caused behavioral impairment, dopaminergic neuronal death, increased Cdk5 and p25 expression, and decreased p35 expression in the nigrostriatal system of mice, whereas KRG dose-dependently alleviated these MPTP-induced changes.ConclusionThese results indicate that KRG can inhibit MPTP-induced dopaminergic neuronal death and suppress the cleavage of p35 to p25 in the SN and the ST, suggesting a possible role for KRG in the treatment of Parkinson's disease

Cre-LoxP-regulated expression of monoclonal antibodies driven by an ovalbumin promoter in primary oviduct cells

<p>Abstract</p> <p>Background</p> <p>A promoter capable of driving high-level transgene expression in oviduct cells is important for developing transgenic chickens capable of producing therapeutic proteins, including monoclonal antibodies (mAbs), in the whites of laid eggs. Ovalbumin promoters can be used as oviduct-specific regulatory sequences in transgenic chickens, but their promoter activities are not high, according to previous reports.</p> <p>Results</p> <p>In this study, while using a previously characterized ovalbumin promoter, we attempted to improve the expression level of mAbs using a Cre/<it>lox</it>P-mediated conditional excision system. We constructed a therapeutic mAb expression vector, pBS-DS-hIgG, driven by the CMV and CAG promoters, in which the expression of the heavy and light chains of humanized immunoglobulin G (hIgG) is preceded by two floxed stuffer reporter genes. In the presence of Cre, the stuffer genes were precisely excised and hIgG expression was induced in pBS-DS-hIgG-transfected 293T cells. In chicken oviduct primary culture cells, hIgG was expressed after transfection of pBS-DS-hIgG together with the ovalbumin promoter-driven Cre expression vector. The expression level of hIgG in these cells was increased 40-fold over that induced directly by the ovalbumin promoter. On the other hand, hIgG was not induced by the ovalbumin promoter-driven Cre in chicken embryonic fibroblast cells.</p> <p>Conclusions</p> <p>The Cre/<it>lox</it>P-based system could significantly increase ovalbumin promoter-driven production of proteins of interest, specifically in oviduct cells. This expression system could be useful for producing therapeutic mAbs at high level using transgenic chickens as bioreactors.</p

Improvement of halitosis by probiotic bacterium Weissella cibaria CMU: A randomized controlled trial

Several in vitro and in vivo studies have evaluated the effect of probiotics on oral health; however, human clinical studies are still limited. Therefore, this study aimed to examine the effects of Weissella cibaria Chonnam Medical University (CMU)-containing tablets on halitosis. This randomized, double-blinded, placebo-controlled study included 100 adults with halitosis (age, 20–70 years). The participants were randomly assigned to the test group (n = 50) and control group (n = 50). One tablet [1 × 108 colony forming units (CFU)/tablet] was to be taken each day over 8 weeks. The concentrations of volatile sulfur compounds (VSCs), bad breath improvement scores, and oral colonization of W. cibaria were measured. Psychosocial indicators including depression, self-esteem, oral health-related quality of life, and subjective oral health status were evaluated. Most variables were assessed at baseline, 4, and 8 weeks, and W. cibaria number and safety variables were assessed at baseline and 8 weeks. Intergroup comparisons were carried out using Student’s t-test, Chi-square test, or Fisher’s exact test on per-protocol analysis. Intragroup differences before and after intake were analyzed using the linear mixed-effect model (LMM). Per-protocol analysis was carried out in the test group (n = 45) and control group (n = 46). Total VSC was significantly lower in the probiotics group than in the placebo group at baseline (week 0, p = 0.046) and at 8 weeks (p = 0.017). The sum of hydrogen sulfide and methyl mercaptan did not differ significantly between the groups at baseline; however, it was significantly lower in the probiotics group than in the placebo group at week 8 (p = 0.012). Bad breath improvement (BBI) scores were significantly reduced at week 8 (p = 0.006) in the probiotics group. Statistically significant intergroup differences were observed for changes in the level of W. cibaria at week 8 (p &lt; 0.001). Psychological indicators significantly improved from baseline to week 8 in the probiotics group. No safety issues were observed in either group. The levels of W. cibaria was higher in patients with halitosis using W. cibaria CMU-containing tablets. The subjective degree of bad breath and psychological indicators were improved in patients with halitosis using W. cibaria CMU-containing tablets

S100A8 and S100A9 in saliva, blood and gingival crevicular fluid for screening established periodontitis: a cross-sectional study

Background Periodontitis is one of major oral diseases, which has no consensus on early screening tool. This study aimed to compare the association and screening ability of S100A8 and S100A9 in saliva, blood and gingival crevicular fluid (GCF) for periodontitis status. Methods We recruited 149 community Korean adults, 50 no or initial periodontitis (NIPERIO) and 99 established periodontitis (PERIO). Using clinical attachment loss and a panoramic radiograph, stage II–IV of new classification of periodontitis proposed at 2018 was considered cases as PERIO. Enzyme linked immunosorbent assay kit was used to quantify S100A8 and S100A9. T-test, analysis of covariance, Mann–Whitney test and correlation analysis were applied to compare the relationship of S100A8 and S100A9 in saliva, blood, and GCF for periodontitis. Receiver operating characteristic curve was applied for screening ability. Results Among S100A8 and S100A9 in saliva, blood and GCF, S100A8 in saliva was significantly higher in PERIO than in NIPERIO (p < 0.05). However, S100A8 and S100A9 in GCF were higher in NIPERIO (p < 0.05). The screening ability of salivary S100A8 was 75% for PERIO, while that of GCF S100A8 was 74% for NIPERIO. Salivary S100A8 was positively correlated to blood S100A8 (p < 0.05). Conclusion Salivary S100A8 could be a potential diagnostic marker for established periodontitis and be useful for screening established periodontitis.This research was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Ministry of Science and ICT, Korea (NRF-2017M3A9B6062986). The funder had no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscrip

A Parametric Study on the Immunomodulatory Effects of Electroacupuncture in DNP-KLH Immunized Mice

This study was conducted to compare the effects of low frequency electroacupuncture (EA) and high frequency EA at acupoint ST36 on the production of IgE and Th1/Th2 cytokines in BALB/c mice that had been immunized with 2,4-dinitrophenylated keyhole limpet protein (DNP-KLH), as well as to investigate the difference in the immunomodulatory effects exerted by EA stimulations at acupoint ST36 and at a non-acupoint (tail). Female BALB/c mice were divided into seven groups: normal (no treatments), IM (immunization only), ST36-PA (IM + plain acupuncture at ST36), ST36-LEA (IM + low frequency (1 Hz) EA at ST36), ST36-HEA (IM + high frequency (120 Hz) EA at ST36), NA-LEA (IM + low frequency (1 Hz) EA at non-acupoint) and NA-HEA (IM + high frequency (120 Hz) EA at non-acupoint). EA stimulation was performed daily for two weeks, and total IgE, DNP-KLH specific IgE, IL-4 and IFN-γ levels were measured at the end of the experiment. The results of this study showed that the IgE and IL-4 levels were significantly suppressed in the ST36-LEA and ST36-HEA groups, but not in the NA-LEA and NA-HEA groups. However, there was little difference in the immunomodulatory effects observed in the ST36-LEA and ST36-HEA groups. Taken together, these results suggest that EA stimulation-induced immunomodulation is not frequency dependent, but that it is acupoint specific