Heavy Group Research Articles

Association between secondhand smoke and liver injury among US non-smoking adults: Mediation analysis of body mass index in the NHANES.

Liver injury is a primary factor in the pathogenesis of most liver diseases, which can lead to liver failure. Secondhand smoke (SHS) is a serious public problem. This research explored the correlation between SHS and the indicators of liver injury. This cross-sectional study was based on the National Health and Nutrition Examination Survey (NHANES) 2011-2016. The relationship between SHS and indicators of liver injury was explored by the weighted linear regression model and smooth curve fitting. The weighted threshold saturation effect model tested the relationship and inflection point between them. Mediation analyses were used to explore whether body mass index (BMI) mediates the correlation between SHS and liver injury indicators. Our cross-sectional study included 3811 non-smoking participants (aged 20-80 years). The full covariate adjustment model (β= -0.05; 95% CI: -0.08 - -0.02) showed a significant and negative correlation between log cotinine and albumin (ALB). Compared to the unexposed group, the ALB, and total protein (TP) were decreased by 0.16 g/dL, 0.26 g/dL in the heavy exposure group [ALB: -0.16 (-0.26 - -0.05), TP: -0.26 (-0.38 - -0.13)], respectively. Smoothed curve fitting revealed a nonlinear relationship between log cotinine and fibrosis-4 index (FIB-4 score), with the inflection point of log cotinine at -1.72. When log cotinine was < -1.72, the log cotinine significantly and positively correlated with the FIB-4 score (β=0.27; 95% CI: 0.06-0.49). BMI partially mediated the effect of SHS exposure on ALB or TP. SHS has harmful effects on the liver in never-smoking adults. BMI partially mediated the effect of SHS exposure on ALB or TP. More prospective and basic research in the future is necessary to focus on validating our results.

Effects of Light Versus Very Heavy Resisted Sprint Training on Multidirectional Speed in Semi-professional Soccer Players.

Baena-Raya, A, Robles-Ruiz, J, Pérez-Castilla, A, Pareja-Blanco, F, and Rodríguez-Pérez, MA. Effects of light versus very heavy resisted sprint training on multidirectional speed in semi-professional soccer players. J Strength Cond Res XX(X): 000-000, 2024-The purpose of this study was to evaluate the effects of an 8-week resisted linear sprint training (RST) program with 2 loading conditions (light vs. very heavy) on linear sprint (LS), curve sprint (CS), and change of direction (COD) performance in young soccer players. Thirty-eight male under-19 soccer players were assessed for 30-m LS, CS, and modified 505 COD tests. Players were randomly allocated into 3 groups: control (n = 18), light (n = 10), and very heavy RST (n = 10). Light and very heavy RST groups performed RST with external loads resulting in a 25 and 75% velocity loss from the player's maximal LS velocity, respectively. The control group did not perform any sprint training. Significant group × time interactions were observed for LS, CS, and COD performances (p < 0.05). The control group showed no performance improvement. Both RST groups showed significant improvements in LS at 10-, 20-, and 30-m (p ≤ 0.03; effect size [ES] ≥ 0.62), whereas no significant changes were observed for the split times (p > 0.05). CS performance was significantly increased by the 2 RST groups (p ≤ 0.03; ES ≥ 0.60), except for light RST on CS right side at 17-m (p = 0.09; ES = 0.46). Change of direction performance was only significantly enhanced by the very heavy RST group (p ≤ 0.001; ES ≥ 0.80). No significant changes between RST groups were observed. In conclusion, using both light and very heavy RST can enhance LS and CS performance, whereas very heavy RST is recommended to optimize COD performance in young soccer players.

Exploring the effects of reduced alcohol consumption on major adverse cardiovascular and cerebrovascular events in chronic heavy drinkers: a nationwide population-based cohort study

Abstract Background/Introduction Chronic heavy alcohol consumption is a well-established risk factor for cardiovascular disease (CVD), and the potential cardiovascular benefits of mild to moderate alcohol consumption need validation, particularly in the context of behavioral change from heavy drinking. Currently, there is a lack of research examining the potential benefits of reduced alcohol consumption in chronic heavy drinkers, specifically in relation to different subtypes of CVD. We hypothesized that habitual changes in alcohol consumption among chronic heavy drinkers would have a long-term prognostic effect on future CVD outcomes. Purpose We investigated the association between reduced alcohol consumption and the risk of major adverse cardiovascular and cerebrovascular events (MACCE) in chronic heavy drinkers. Methods From the Korean National Health Insurance Service-Health Screening database, we included a cohort of chronic heavy drinkers who underwent serial health examinations over two consecutive time-periods (first period: 2005–2008; second period: 2009–2012). Heavy drinking was defined according to the National Institute on Alcohol Abuse and Alcoholism criteria as &amp;gt;56 g/day or &amp;gt;196 g/week for men, and &amp;gt;42 g/day or &amp;gt;98 g/week for women. Overall, 13,854 heavy drinkers at baseline (mean age 55.84 ± 5.98 years; 91.6 % men) were categorized into two groups based on the alcohol consumption changes in the second period: sustained heavy drinking (n=9,403; 67.9%) or reduced drinking (n=4,451; 32.5%). The primary outcome was MACCE, a composite of nonfatal myocardial infarction or angina undergoing revascularization, any stroke accompanied by hospitalization, and all-cause death during follow-up. Results In this nationwide population-based cohort study, during a total follow-up of 107,102 person-years, the sustained heavy drinking group experienced a significantly higher incidence of MACCE than the reduced drinking group (incidence rate, 825 vs. 655 per 100,000 person-years; log-rank p=0.004). Reduced alcohol consumption was associated with a 28% lower risk of MACCE compared to sustained heavy drinking (adjusted-hazard ratio [HR]: 0.780, 95% confidence interval [CI] 0.656–0.928). These benefits were mostly driven by a significant reduction in the incidence of angina (adjusted-HR: 0.631, 95% CI 0.425–0.926) and ischemic stroke (adjusted-HR: 0.657, 95% CI 0.472–0.914). The preventive effects of reduced alcohol intake were consistently observed across various subgroups of heavy drinkers, except for smoking status (p-interaction=0.015) and even after including abstainers in the sensitivity analysis. Conclusion Reduced alcohol consumption in heavy drinkers could lower the future risk of CVD, with the most pronounced benefits expected for stable/unstable angina and ischemic stroke. Further research is warranted to explore the optimal strategies for promoting sustained reductions in alcohol intake.Cumulative MACCE incidence curves

Organic Room Temperature Phosphorescence from BN‐Substituted Xanthene Derivatives

Emissive organic materials are predominantly fluorescent and there is significant interest in realizing and understanding examples that defy this paradigm and exhibit phosphorescence under ambient conditions. Organic room temperature phosphorescence (ORTP) offers the long‐lived excited states and bathochromically‐shifted emission maxima of phosphorescence without the use of potentially toxic and expensive transition metals. Most ORTP materials rely on well‐studied structural motifs that include aryl carbonyls, sulfones, and heavy main group elements. We report the unexpected ORTP of a series of heavy atom‐free BN‐substituted xanthene derivatives. The creation of heteroatom‐rich scaffolds, combined with stabilizing C–H···F interactions in the solid‐state, resulted in oxygen‐tolerant heavy atom‐free organic phosphorescence without relying on the use of cryogenic temperatures, polymer matrices, or host‐guest interactions. The observation of ORTP in these simple systems sets a blueprint for the further development of heavy atom‐free organic phosphors.

Organic Room Temperature Phosphorescence from BN-Substituted Xanthene Derivatives.

Emissive organic materials are predominantly fluorescent and there is significant interest in realizing and understanding examples that defy this paradigm and exhibit phosphorescence under ambient conditions. Organic room temperature phosphorescence (ORTP) offers the long-lived excited states and bathochromically-shifted emission maxima of phosphorescence without the use of potentially toxic and expensive transition metals. Most ORTP materials rely on well-studied structural motifs that include aryl carbonyls, sulfones, and heavy main group elements. We report the unexpected ORTP of a series of heavy atom-free BN-substituted xanthene derivatives. The creation of heteroatom-rich scaffolds, combined with stabilizing C-H···F interactions in the solid-state, resulted in oxygen-tolerant heavy atom-free organic phosphorescence without relying on the use of cryogenic temperatures, polymer matrices, or host-guest interactions. The observation of ORTP in these simple systems sets a blueprint for the further development of heavy atom-free organic phosphors.

Latitudinal trends in an invasive plant: genetic differentiation, phenotypic plasticity, and the effects of heavy metals and herbivores on growth, defence, and reproductive characteristics

Abstract Background and Aims Invasive species usually demonstrate remarkable adaptability across diverse environments, successfully inhabiting a wide variety of regions. This adaptability often links to genetic differentiation and phenotypic plasticity, leading to latitudinal trends in phenotypic traits. In this study, we collected seeds of invasive plant Phytolacca americana from different latitudes and planted them in homogeneous gardens to investigate the latitudinal variation of P. americana phenotypic traits and to evaluate the effects of herbivory and heavy metals on plant growth, defence, and reproductive characteristics. Methods P. americana seeds from different latitudes were planted in a homogeneous garden. For the experimental treatment, the seeds were divided into four groups: a heavy metal treatment group and its corresponding control group, and a cover treatment group with its corresponding control group. After the fruits matured, their growth, reproduction, and defence indicators were measured. Key Results Significant latitudinal trends were observed in P. americana’s growth and defence characteristics, including changes in branch number, underground biomass, total biomass, and leaf tannin content. Compared to previous field surveys on P. americana, our study found that the latitude trends in growth structure and defence traits were consistent. But the latitudinal trend of reproductive structure is different. Moreover, heavy metals and herbivory substantially influenced the plant’s growth, reproduction, and defence mechanisms, further shaping its latitudinal patterns. Conclusions The observed phenotypic variations in P. americana across latitudes can be largely attributed to the synergistic effects of phenotypic plasticity and genetic variation. At a broader geographical scale, adaptations to heavy metal stress and herbivory pressure among different P. americana populations involve distinct trade-offs related to growth, reproduction, and defence strategies.

Carbodiphosphorane-Activated Distibene and Dibismuthene Dications.

Low-valent antimony and bismuth have emerged as novel platforms for achieving reversible small-molecule activation at main-group metals. Although various examples of oxidative addition reactions at monomeric Sb(I) and Bi(I) have been reported, the chemistry of the heavy group 15 Sb(I)═Sb(I)/Bi(I)═Bi(I) double bonds toward small molecules remains largely unexplored. In this study, we present a straightforward synthesis of distibene and dibismuthene dications coordinated with a neutral carbodiphosphorane (CDP) ligand. The nonbonding interactions between the occupied p-orbital at the CDP ligand and the π-bonding orbital of the Sb═Sb/Bi═Bi bonds yield compounds with exceptionally small HOMO-LUMO gaps. In addition, the reduction of steric hindrance compared to known neutral derivatives stabilized with bulky aryl groups allows for better accessibility of the double bonds. This high reactivity is demonstrated in the oxidative addition of distibene to diphenyldisulfide as well as in [2+2] cycloadditions to alkynes. Additionally, the Sb═Sb bond reversibly adds to 2,3-dimethylbutadiene in a [4+2] cycloaddition reaction.

Heavy ion detection in thermally and non-thermally treated CR-39 detectors: Fission fragment ranges and etchable track lengths

For the first time, etched track diameter and over-etched track diameter (OETD) measurements have been used to determine etchable track lengths in thermally treated poly allyl diglycole carbonate (PADC) in the form of CR-39, as well as heavy ion track ranges in non-thermally treated samples. These heavy ions are produced spontaneously from 252Cf radioactive source as fission fragments. Isochronal heating experiment was conducted on CR-39 detectors prior to their irradiation to 252Cf radioactive source. In a reverse sequence, another set of detector films was first subjected to 252Cf irradiation and then thermally treated as described above. The diameters of etched heavy ion tracks in non-thermally treated and thermally treated CR-39 detectors have been measured as a function of etching time at different heating temperatures and times. The fission fragment ranges in non-thermally treated CR-39 detectors determined using the OETD method were found to be 17.7 ± 0.2 μm for the heavy group and 21.8 ± 0.3 μm for the light group, whereas the etchable track lengths in thermally treated detectors are by far lesser than that those of non-thermally treated ones. The results of heavy ion ranges in non-thermally treated detectors are in excellent agreement with theoretical calculations based on SRIM code. While in the case of the etchable track lengths of these heavy ions in thermally treated detectors, there is no such theoretical data for comparison with experiment till present.

Imidazole ionic liquid effects on coal swelling behavior and pyrolysis characteristics: Experiment and molecular simulation

In view of low-rank coal conventional swelling solvent large pollution and the clean efficient utilization of coal, the effects of imidazole ionic liquid (IL) pretreatment with different anion groups as green solvent on coal thermal expansion and pyrolysis performance were investigated. IL interacts with coal molecules, destroying the hydrogen bonds, resulting coal expansion. Different anion groups have different modification effects, [Bmim]Cl has the best swelling effect, which is 17.37 % higher than raw coal, and the best modification time is 24 h. In addition, IL modification has a catalytic effect on coal pyrolysis, which can significantly reduce the maximum weight loss temperature and increase tar content. Coal solvent pretreatment provides a good theoretical basis for application of swelling and pyrolysis. The reduction of thermochemical reaction temperature not only reduces the content of heavy groups in pyrolysis products, but also provides new ideas for carbon emission reduction.

Relating distractor suppression to problematic drinking behavior

BackgroundImpaired cognitive control has been linked to weakened self-regulatory processes underlying compulsive substance intake. Previous research has provided evidence for impaired task performance in substance-abusing groups during Stroop and Go/No-Go tasks. Mechanisms of distractor suppression in visual search might also involve overlapping regulatory components that support goal-directed behavior by resolving the attentional competition between distractors and the target of search. However, the efficiency of learning-dependent distractor suppression has not been examined in the context of drug abuse and a direct comparison between cognitive control and distractor suppression is lacking. MethodA total of 84 participants were assigned either to the heavy drinking group (ALC, n = 42) or the control group (CTL, n = 42) based on self-reported substance use. Participants completed the Alcohol Use Disorders Identification Test (AUDIT) and Barratt Impulsiveness Scale (BIS). After that, participants completed a computerized version of the Stroop task, Go/No-go task, and a visual search task measuring learning-dependent distractor suppression. ResultsThe Stroop effect and the frequency of no-go errors did not differ between groups. However, learned distractor suppression was significantly blunted in the ALC group compared to the control group. Across participants, performance on the Stroop and Go/No-go task were correlated, while the magnitude of distractor suppression was related to neither. ConclusionsOur findings support a divergence of mechanistic processes underlying cognitive control and attentional control, and demonstrate impaired learning-dependent distractor suppression in heavy drinkers relative to a control group. Impaired distractor suppression offers new insight into why drug cues can be difficult to ignore.

(Invited) Designing Photocatalytic Membrane to Direct Electron and Hole Transport

Surface interaction of chromophore or redox active molecule which dictate the efficiency of energy/electron transfer, plays an important role in realizing photocatalytic and optoelectronic applications. Metal halide perovskite nanocrystals are interesting in the sense that they can either transfer energy or selectively transfer electrons or holes to the adsorbed molecules.1,2 The presentation will focus on two specific scenarios of the flow of energy and electron processes in CsPbX3 (X= Br, I) nanocrystal-molecular hybrids. The energy transfer is probed through three moleculr acceptors – rhodamine B (RhB), rhodamine isothiocyanate (RhB-NCS), and rose Bengal (RoseB), which contain an increasing degree of heavy atom pendant groups. Electron and/or hole transfer from excited CsPbX3 nanocrystals to a molecular relay present near the interface offers another avenue to directly convert light energy into chemical energy. Such interfacial electron transfer of semiconductor nanocrystals has been widely explored in photocatalytic processes. A basic understanding of the fundamental differences between the two excited deactivation processes (energy and charge transfer) and ways to modulate them should enable design of more efficient light harvesting assemblies with semiconductor and molecular systems.

Modulating Heavy Atom Effect in Germylene for Persistent Room Temperature Phosphorescence.

It is worth but still challenging to develop the low-valent main group compounds with persistent room temperature phosphorescence (pRTP). Herein, we presented germylene-based persistent phosphors by introduction of low-valent Ge center into chromophore. A novel phosphors CzGe and its series of derivatives, namely CzGeS, CzGeSe, CzGeAu, and CzGeCu, were synthesized. Experiments and theoretical calculations reveal that the pRTP behavior were "turn on" due to the heavy atom effect of germylene. More importantly, the low-valent of oxidation state and structural traits propelled GeCz had a balance between the intersystem crossing and the shortening of lifetime caused by the heavy atoms, resulting the ultralong lifetime of 309 ms and phosphorescent quantum efficiency of 15.84 %, which is remarkable among heavy main group phosphors. This research provides valuable insights to the design of heavy atoms in phosphors and expand the applications of germylene chemistry.

Risk assessment of citrinin in Chinese dark tea and inhibitory effects of tea polyphenols on citrinin production

The fungus Penicillium citrinum (P. citrinum), which is found in Chinese dark tea, is involved in the production of citrinin (CIT), a secondary metabolite with renal toxicity. In this study, a rapid method was used to detect CIT in Chinese dark tea samples from different regions and years. Of the 216 samples tested, 5 were detected to have CIT contamination, with a concentration ranging from 272.43 ± 16.57 to 649.68 ± 62.16 μg kg−1. Risk assessment for consuming dark tea showed that four heavy intake consumer groups in the deterministic risk assessment had hazard quotients (HQ) > 1, and the HQ for the probabilistic risk assessment was significantly below the acceptable level of 1.0. Furthermore, we found that tea polyphenols (TPs) inhibited the growth of P. citrinum. Transcriptome results showed that there were 483 downregulated and 783 upregulated genes between the TPs and control groups. Of which, orf1 and ctnD were significantly downregulated, demonstrating that TPs can affect CIT biosynthesis. Our research indicates that CIT in dark tea is within an acceptable risk level, and provides new insights into the inhibition of CIT. Furthermore, this study suggests that the suppression of CIT in dark tea by polyphenols make the consumption of dark tea safe.

Metabolic dysfunction-associated fatty liver disease and heavy alcohol consumption increase mortality:A nationwide study.

The effects of excessive alcohol consumption on the prognosis of metabolic dysfunction-associated fatty liver disease (MAFLD) remain unclear. We investigated all-cause and cause-specific mortality according to the amount of alcohol consumed by Asian individuals with MAFLD. This nationwide retrospective study included 996,508 adults aged 40-79years who underwent health check-ups between 2009 and 2012. Participants were categorized by the alcohol consumption-non-alcohol, moderate alcohol, and heavy alcohol group (≥ 30g/day for men, ≥ 20g/day for women) and by the combination of the presence or absence of MAFLD. Hepatic steatosis was defined as the fatty liver index ≥ 30. Cox analyses were used to analyze the association between alcohol consumption and MAFLD and all-cause and cause-specific mortality. MAFLD significantly increased all-cause, liver-, and cancer-related mortality. Individuals with both MAFLD and heavy alcohol consumption expressed the highest mortality risk in liver-related mortality compared to non-MAFLD and non-alcohol group (adjusted hazard ratio (HR), 9.8; 95% confidence interval (CI), 8.20-12.29). Regardless of MAFLD, heavy alcohol consumption increased the risk of liver- and cancer-related mortality. MAFLD and heavy alcohol consumption increased all-cause, liver-, and cancer-related mortality. Heavy alcohol consumption and MAFLD synergistically increase liver-related mortality.

#939 Association between alcohol consumption and the risk of incident chronic kidney disease in community-dwelling older adults

Abstract Background and Aims The relationship between alcohol consumption and kidney function decline is not well established, especially in older adults. This study aimed to investigate the effects of alcohol consumption on the risk of incident chronic kidney disease (CKD) in community-dwelling older adults. Method Adults aged ≥ 65 years with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 and without proteinuria between 2009 and 2010 were recruited and followed through December 2018 from a Korean national population-based cohort. Alcohol consumption was categorised into non-, mild, moderate, and heavy drinking groups based on self-administered questionnaires. New-onset CKD was defined as an eGFR &amp;lt;60 mL/min/1.73 m2. Results Of the total 122,319 subjects, the non-, mild, moderate, and heavy drinking groups were 99,091 (81.0%), 14,842 (12.1%), 4,257 (3.5%), and 4,139 (3.4%), respectively. During follow-up, 19,796 (20.0%), 4,636 (31.2%), 1,696 (39.8%), and 1,695 (41.0%) developed CKD in the non-, mild, moderate, and heavy drinking groups. Univariate Cox regression analyses showed a significantly increased risk of incident CKD in older adults in all drinking groups compared to non-drinkers (all P &amp;lt; 0.001). However, hazard ratios (HR) for developing CKD were 0.90 (95% confidence interval [CI] 0.87–0.94, P &amp;lt; 0.001) for mild, 0.89 (95% CI 0.84–0.95, P &amp;lt; 0.001) for moderate, and 0.93 (95% CI 0.88–0.99, P = 0.027) for heavy drinkers after fully adjusting for confounding variables. This inverse relationship between alcohol consumption and CKD risk was observed in males in all drinking groups, whereas in females it was found only in mild drinkers. Conclusion In the subgroup analysis, the beneficial effect of alcohol consumption on incident CKD was prominent among moderate drinkers aged 65–75 years, male mild drinkers aged ≥ 75 years, and female mild drinkers aged &amp;lt; 85 years. This study shows that alcohol consumption is inversely associated with the risk of incident CKD in older adults. Further studies are required to elucidate the effects of alcohol on kidney damage in older adults.

Relationship between nitrate, heavy metal, and sterols contents in Japanese agricultural soils with risk of groundwater pollution

In Japanese agricultural lands, nitrate-nitrogen contamination of soil and groundwater often occurs due to the application of livestock excrements and compost. Therefore, rural soils in Japan were sampled and analyzed for nitrate-nitrogen leaching, heavy metal content, and sterols associated with livestock excrement and compost to calculate contamination risk indicators. The results were analyzed using self-organizing maps and cluster analysis. Nitrate-nitrogen content using water extraction was detected in most of the sampled soils. In addition, many samples from areas that were already severely contaminated with nitrate-nitrogen showed particularly high concentrations. Coprostanol, an indicator of fecal contamination, was detected in more than half of the samples. The main source of nitrate-nitrogen contamination in these areas is livestock excrement and compost. Self-organization maps showed that areas with high nitrate-nitrogen contamination also corresponded to areas with high copper and zinc soil contents. The self-organization maps and cluster analysis resulted in five clusters: a nitrate-contaminated group mainly originating from livestock excrement and compost, a heavy metal-contaminated group, a general group, a nitrate-contaminated group mainly originating from chemical fertilizers, and a contaminated group with potentially hazardous substances requiring attention. Authorities and decision-makers can use the results to prioritize areas requiring remediation.

Association between secondhand smoke exposure and rheumatoid arthritis in US never-smoking adults: a cross-sectional study from NHANES

While smoking is widely acknowledged as a risk factor for rheumatoid arthritis (RA), the connection between secondhand smoke (SHS) exposure and RA in never-smoking adults remains limited and inconsistent. This study aims to explore and quantify this association using serum cotinine levels. We conducted a cross-sectional study with 14,940 adults who self-report as never smokers, using National Health and Nutrition Examination Survey data from 1999 to 2018. Based on previous literature, SHS exposure was categorized into four groups according to serum cotinine levels. Compared to individuals in the unexposed group (serum cotinine < 0.05 ng/mL), the adjusted odds ratio (OR) for RA was 1.37 (95% CI 1.14–1.64, p = 0.001) in the low exposure group (serum cotinine at 0.05 to 0.99 ng/mL) after adjusting for covariates. However, no significant association was found in the moderate exposure group (serum cotinine at 1 to 10 ng/mL) or the heavy exposure group (serum cotinine ≥ 10 ng/mL). Furthermore, we detected a non-linear, positively saturated correlation between the cotinine levels after log2 transformation and RA, with a turning point at approximately − 2.756 ng/mL (OR = 1.163, 95% CI 1.073–1.261, p = 0.0002). The stability of the results was confirmed by subgroup analysis.

How the Amount of Hartree-Fock Exchange Affects the Observation of the Pseudo Jahn-Teller Effect

Heavy group 14 analogs of planar carbon molecules are well known to prefer bent or pyramidalized geometries. The pseudo Jahn-Teller effect (pJTE) is a general approach to understanding the origin of such molecular geometries. Computationally intensive multi-reference post Hartree-Fock methods are generally required to obtain values relevant to the pJTE. However, an alternative approach, using more computationally efficient density functional theory (DFT) and fitting a model vibronic Hamiltonian, can account for the pJTE parameters. Previous studies have detailed the effect of both integration grid size and exact exchange on various properties including the nature of stationary points (i.e., transition structure v. minimum) on potential energy surfaces but none have addressed the root cause of such discrepancies. In this work we examine two contentious stationary points belonging to planar disilene and 2Si TCNQ from the perspective of the pseudo Jahn-Teller effect (pJTE) using DFT methods. First the planar stationary points are characterized using a variety of model chemistries and integration grids. The effect of the amount of Hartree-Fock exchange is then studied and the usage of DFT for assessing pJT parameters is explored. It is shown that the DFT approach is a viable alternative for determining values relevant to the pJTE. A complementary cusp catastrophe theory approach to the problem is also introduced. Difficulties associated with the DFT-based approach to the study of the pJTE are discussed and changes in the electronic structure are explored using the Quantum Theory of Atoms in Molecules.

Study of the Effects of Remote Heavy Group Vibrations on the Temperature Dependence of Hydride Kinetic Isotope Effects of the NADH/NAD+ Model Reactions.

It has recently been observed that the temperature(T)-dependence of KIEs in H-tunneling reactions, characterized by isotopic activation energy difference (ΔEa = EaD - EaH), is correlated to the rigidity of the tunneling ready states (TRSs) in enzymes. A more rigid system with narrowly distributed H-donor-acceptor distances (DADs) at the TRSs gives rise to a weaker T-dependence of KIEs (i.e., a smaller ΔEa). Theoreticians have attempted to develop new H-tunneling models to explain this, but none has been universally accepted. In order to further understand the observations in enzymes and provide useful data to build new theoretical models, we have studied the electronic and solvent effects on ΔEa's for the hydride-tunneling reactions of NADH/NAD+ analogues. We found that a tighter charge-transfer (CT) complex system gives rises to a smaller ΔEa, consistent with the enzyme observations. In this paper, we use the remote heavy group (R) vibrational effects to mediate the system rigidity to study the rigidity-ΔEa relationship. The specific hypothesis is that slower vibrations of a heavier remote group would broaden the DAD distributions and increase the ΔEa value. Four NADH/NAD+ systems were studied in acetonitrile but most of such heavy group vibrations do not appear to significantly increase the ΔEa. The remote heavy group vibrations in these systems may have not affected the CT complexation rigidity to a degree that can significantly increase the DADs, and further, the ΔEa values.

Effects of Improper Mechanical Force on the Production of Sonic Hedgehog, RANKL, and IL-6 in Human Periodontal Ligament Cells In Vitro.

Improper mechanical stress may induce side effects during orthodontic treatment. If the roots and alveolar bones are extensively resorbed following excess mechanical stress, unplanned tooth mobility and inflammation can occur. Although multiple factors are believed to contribute to the development of side effects, the cause is still unknown. Sonic hedgehog (Shh), one of the hedgehog signals significantly associated with cell growth and cancer development, promotes osteoclast formation in the jawbone. Shh may be associated with root and bone resorptions during orthodontic treatment. In this study, we investigated the relationships between Shh, RANKL, and IL-6 in human periodontal ligament (hPDL) cells exposed to improper mechanical force. Weights were placed on hPDL cells and human gingival fibroblasts (HGFs) for an optimal orthodontic force group (1.0 g/cm2) and a heavy orthodontic force group (4.0 g/cm2). A group with no orthodontic force was used as a control group. Real-time PCR, SDS-PAGE, and Western blotting were performed to examine the effects of orthodontic forces on the expression of Shh, RANKL, and IL-6 at 2, 4, 6, 8, 12, and 24 h after the addition of pressure. The protein expression of Shh was not clearly induced by orthodontic forces of 1.0 and 4.0 g/cm2 compared with the control in HGFs and hPDL cells. In contrast, RANKL and IL-6 gene and protein expression was significantly induced by 1.0 and 4.0 g/cm2 in hPDL cells for forces lasting 6~24 h. However, neither protein was expressed in HGFs. RANKL and IL-6 expressions in response to orthodontic forces and in the control were clearly inhibited by Shh inhibitor RU-SKI 43. Shh did not directly link to RANKL and IL-6 for root and bone resorptions by orthodontic force but was associated with cell activities to be finally guided by the production of cytokines in hPDL cells.