Roles of Baseline Intrinsic Capacity and its Subdomains on the Overall Efficacy of Multidomain Intervention in Promoting Healthy Aging among Community-Dwelling Older Adults: Analysis from a Nationwide Cluster-Randomized Controlled Trial.

BACKGROUND: Impaired intrinsic capacity (IC), which affects approximately 90% of older adults, is associated with a significantly heightened risk of frailty and cognitive decline. Existing evidence suggests that multidomain interventions have the potential to enhance cognitive performance and yield positive effects on physical frailty. OBJECTIVE: To examine roles of baseline IC and its subdomains on the efficacy of multidomain interventions in promoting healthy aging in older adults. DESIGN: a cluster-randomized controlled trial. SETTING AND PARTICIPANTS: 1,054 community-dwelling older adults from 40 community-based clusters across Taiwan. INTERVENTION: A 12-month pragmatic multidomain intervention of exercise, cognitive training, nutritional counseling and chronic condition management. MEASUREMENTS: Baseline IC was measured by 5 subdomains, including cognition (Montreal Cognitive Assessment, MoCA), sensory (visual and hearing impairment), vitality (handgrip strength or Mini-Nutritional Assessment-short form), psychological well-being (Geriatric Depression Scale-5), and locomotion (6m gait speed). Outcomes of interest were cognitive performance (MoCA scores) and physical frailty (CHS frailty score) over a follow-up period of 6 and 12 months. RESULTS: Of all participants (mean age:75.1±6.4 years, 68.6% female), about 90% participants had IC impairment at baseline (2.0±1.2 subdomains). After covariate adjustment using a generalized linear mixed model (GLMM), the multidomain intervention significantly prevented cognitive declines and physical frailty, particularly in those with IC impairment ≥ 3 subdomains (MoCA: coefficient: 1.909, 95% CI: 0.736 ~ 3.083; CHS frailty scores: coefficient = -0.405, 95% CI: -0.715 ~ -0.095). To assess the associations between baseline poor capacity in each IC subdomain and MoCA/CHS frailty scores over follow-up, a 3-way interaction terms (time*intervention*each poorer IC subdomains) were added to GLMM models. Significant improvements in MoCA scores were shown for participants with poorer baseline cognition (coefficient= 1.138, 95% CI: 0.080 ~ 2.195) and vitality domains (coefficient= 1.651, 95% CI: 0.541 ~ 2.760). The poor vitality domain also had a significant modulating effect on the reduction of CHS frailty score after the 6- and 12-month intervention period (6 months: coefficient= -0.311, 95% CI: -0.554 ~ -0.068; 12 months: coefficient= -0.257, 95% CI: -0.513 ~ -0.001). CONCLUSION AND IMPLICATIONS: A multidomain intervention in community-dwelling older adults improves cognitive decline and physical frailty, with its effectiveness influenced by baseline IC, highlighting the importance of personalized strategies for healthy aging.

The Effectiveness of Frailty Intervention for Older Patients with Frailty during Hospitalization.

OBJECTIVES: This study aims to assess the effectiveness of a multidomain intervention program on the change in functional status of hospitalized older adults. DESIGN: This single-arm, prospective, non-randomized interventional study investigates the efficacy of a multidomain interventional program including cognitive stimulation activity, simple exercises, frailty education, and nutrition counseling. SETTING AND PARTICIPANTS: At a tertiary hospital in southern Taiwan, 352 eligible patients were sequentially enrolled. Included patients were aged ≥65 years (mean age, 79.6 ± 9.0 years; 62% male), scored 3-7 on the Clinical Frailty Scale (CFS), and were hospitalized in the geriatric acute ward. INTERVENTION: Those receiving standard care (physical rehabilitation and nutrition counseling) during January-July 2019 composed the historical control group. Those receiving the multidomain intervention during August-December 2019 composed the intervention group. MEASUREMENTS: The primary outcome was the change in activities of daily life (ADL) and frailty status, as assessed by Katz Index and Clinical Frailty Scale, with using the generalized estimating equation model. The length of hospital stay, medical costs, and re-admission rates were secondary outcomes. RESULTS: Participants undergoing intervention (n = 101; 27.9%) showed greater improvements in the ADL and CFS during hospitalization (ADL adjusted estimate, 0.61; 95% CI, 0.11-1.11; p = 0.02; CFS adjusted estimate, -1.11; 95% CI, -1.42- -0.80; p < 0.01), shorter length of hospital stay (adjusted estimate, -5.00; 95% CI, -7.99- -2.47; p < 0.01), lower medical costs (adjusted estimate, 0.58; 95% CI, 0.49-0.69; p < 0.01), and lower 30- and 90-day readmission rates (30-day adjusted OR [aOR], 0.12; 95% CI, 0.27-0.50; p < 0.01; 60-day aOR, 0.04; 95% CI, 0.01-0.33; p < 0.01) than did controls. CONCLUSIONS: Participation in the multidomain intervention program during hospitalization improved the functional status and decreased the hospital stay length, medical costs, and readmission rates of frail older people.

Prognostic Impact of Delirium in Older People With/Without Dementia: A Retrospective Cohort Study in Taiwan.

OBJECTIVES: To elucidate the hypothetically different interactions between delirium and post-discharge prognostic indicators in elderly hospital inpatients with versus without dementia. DESIGN: Retrospective cohort study of claims data by Taiwan National Health Insurance beneficiaries between 2002-2013. SETTING: Records of public hospital admissions in the Taiwan National Health Insurance Research database. PARTICIPANTS: Propensity-score matched subgroups of patients with delirium superimposed on dementia (n = 922) versus dementia alone (n = 922), delirium alone (n = 680) versus neither delirium nor dementia (n = 680). MEASUREMENTS: Mortality, emergency department visits, readmissions, and psychotropic drug use, within 30, 180, and 365 days of discharge, were analyzed using multivariate proportional hazards or logistic regression analyses. RESULTS: Delirium superimposed on dementia was not associated with increased post-discharge mortality, or emergency department visits, but significantly increased the risk of readmissions at 365-day follow-up (adjusted HR, 95% CI: 1.26, 1.01-1.56). However, delirium without dementia was significantly associated with increased post-discharge mortality, emergency department visits and readmissions at 180 days and 365 days (respective adjusted HRs: mortality, 1.63 and 1.79; adjusted ORs: emergency department visits, 1.89 and 1.81; readmissions, 1.47 and 1.53). Delirium in patients both with dementia and without, was associated with six-fold higher likelihood of in-hospital psychotropic drug use, and doubled post-discharge psychotropic drug usage. CONCLUSIONS: The obvious association between in-hospital delirium and worsened long-term prognosis, irrespective of dementia, raises awareness to warrants proactive and multimodal prevention and intervention strategies. Furthermore, the mechanisms about different influence of delirium for patients with/without dementia need to be further explored.

The Adverse Effects of Physical Restraint Use among Older Adult Patients Admitted to the Internal Medicine Wards: A Hospital-Based Retrospective Cohort Study.

OBJECTIVES: To evaluate the negative effect of physical restraint use on the hospital outcomes of older patients. DESIGN: A retrospective cohort study. SETTING: Internal medicine wards of a tertiary medical center in Taiwan. PARTICIPANTS: Subjects aged 65 years and over who were admitted during April to Dec 2017 were recruited for study. MEASUREMENTS: Demographic data, geriatric assessments (polypharmacy, visual impairment, hearing impairment, activities of daily living before and after admission, risk of pressure sores, change in consciousness level, mood condition, history of falls in the previous year, risk of malnutrition and pain) and hospital conditions (admission route, department of admission, length of hospital stay and mortality) were collected for analysis. RESULTS: Overall, 4,352 participants (mean age 78.7±8.7 years, 60.2% = male) were enrolled and 8.3% had physical restraint. Results of multivariate logistic regression showed that subjects with physical restraints were at greater risk of functional decline (adjusted odds ratio 2.136, 95% confidence interval 1.322-3.451, p=0.002), longer hospital stays (adjusted odds ratio 5.360, 95% confidence interval 3.627-7.923, p<0.001) and mortality (adjusted odds ratio 4.472, 95% confidence interval 2.794-7.160, p<0.001) after adjustment for covariates. CONCLUSION: The use of physical restraints during hospitalization increased the risk of adverse hospital outcomes, such as functional decline, longer length of hospital stay and mortality.

Predictive Effect of Malnutrition on Long-Term Clinical Outcomes among Older Men: A Prospectively Observational Cohort Study.

OBJECTIVES: To determine whether nutritional status can predict 3-year cognitive and functional decline, as well as 4-year all-cause mortality in older adults. DESIGN: Prospectively longitudinal cohort study. SETTING AND PARTICIPANTS: The study recruited 354 men aged 65 years and older in the veteran's retirement community. MEASURES: Baseline nutritional status was evaluated using the Mini-Nutritional Assessment-Short Form (MNA-SF). Cognitive function and Activities of Daily Living (ADL) function were determined by the Mini-Mental State Examination (MMSE) and the Barthel Index, respectively. Three-year cognitive and functional decline were respectively defined as a >3 point decrease in the MMSE scores and lower ADL scores than at baseline. Univariate and multivariable logistic regression analyses were conducted to identify nutritional status as a risk factor in poor outcome. The Kaplan-Meier method and Cox proportional regression models were used to estimate the effect of malnutrition risk on the mortality. RESULTS: According to MNS-SF, the prevalence of risk of malnutrition was 53.1% (188/354). Multivariate logistic regression found risk of malnutrition significantly associated with 3-year cognitive decline (Adjusted odds ratio [OR] 2.07, 95% Confidence Interval [CI] 1.05-4.08, P =0.036) and functional decline (Adjusted OR 1.83, 95% CI 1.01-3.34, P =0.047) compared with normal nutritional status. The hazard ratio (HR) for all-cause mortality was 1.8 times higher in residents at risk of malnutrition (Adjusted HR 1.82, 95% CI 1.19-2.79, P =0.006). CONCLUSIONS: Our results provide strong evidence that risk of malnutrition can predict not only cognitive and functional decline but also risk of all-cause mortality in older men living in a veteran retirement's community. Further longitudinal studies are needed to explore the causal relationship among nutrition, clinical outcomes, and the effect of an intervention for malnutrition.

Unique Gap Structure and Symmetry of the Charge Density Wave in Single-Layer VSe_{2}.

Single layers of transition metal dichalcogenides (TMDCs) are excellent candidates for electronic applications beyond the graphene platform; many of them exhibit novel properties including charge density waves (CDWs) and magnetic ordering. CDWs in these single layers are generally a planar projection of the corresponding bulk CDWs because of the quasi-two-dimensional nature of TMDCs; a different CDW symmetry is unexpected. We report herein the successful creation of pristine single-layer VSe_{2}, which shows a (sqrt[7]×sqrt[3]) CDW in contrast to the (4×4) CDW for the layers in bulk VSe_{2}. Angle-resolved photoemission spectroscopy from the single layer shows a sizable (sqrt[7]×sqrt[3]) CDW gap of ∼100 meV at the zone boundary, a 220 K CDW transition temperature twice the bulk value, and no ferromagnetic exchange splitting as predicted by theory. This robust CDW with an exotic broken symmetry as the ground state is explained via a first-principles analysis. The results illustrate a unique CDW phenomenon in the two-dimensional limit.

Large quantum-spin-Hall gap in single-layer 1T' WSe2.

Two-dimensional (2D) topological insulators (TIs) are promising platforms for low-dissipation spintronic devices based on the quantum-spin-Hall (QSH) effect, but experimental realization of such systems with a large band gap suitable for room-temperature applications has proven difficult. Here, we report the successful growth on bilayer graphene of a quasi-freestanding WSe2 single layer with the 1T' structure that does not exist in the bulk form of WSe2. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy/spectroscopy (STM/STS), we observe a gap of 129 meV in the 1T' layer and an in-gap edge state located near the layer boundary. The system's 2D TI characters are confirmed by first-principles calculations. The observed gap diminishes with doping by Rb adsorption, ultimately leading to an insulator-semimetal transition. The discovery of this large-gap 2D TI with a tunable band gap opens up opportunities for developing advanced nanoscale systems and quantum devices.

Strain Engineering a 4a×√3a Charge Density Wave Phase in Transition Metal Dichalcogenide 1T-VSe2.

We report a rectangular charge density wave (CDW) phase in strained 1T-VSe2 thin films synthesized by molecular beam epitaxy on c-sapphire substrates. The observed CDW structure exhibits an unconventional rectangular 4a×√3a periodicity, as opposed to the previously reported hexagonal 4a×4a structure in bulk crystals and exfoliated thin layered samples. Tunneling spectroscopy shows a strong modulation of the local density of states of the same 4a×√3a CDW periodicity and an energy gap of 2ΔCDW = (9.1 ± 0.1) meV. The CDW energy gap evolves into a full gap at temperatures below 500 mK, indicating a transition to an insulating phase at ultra-low temperatures. First-principles calculations confirm the stability of both 4a×4a and 4a×√3a structures arising from soft modes in the phonon dispersion. The unconventional structure becomes preferred in the presence of strain, in agreement with experimental findings.

Emergence of charge density waves and a pseudogap in single-layer TiTe2.

Two-dimensional materials constitute a promising platform for developing nanoscale devices and systems. Their physical properties can be very different from those of the corresponding three-dimensional materials because of extreme quantum confinement and dimensional reduction. Here we report a study of TiTe2 from the single-layer to the bulk limit. Using angle-resolved photoemission spectroscopy and scanning tunneling microscopy and spectroscopy, we observed the emergence of a (2 × 2) charge density wave order in single-layer TiTe2 with a transition temperature of 92 ± 3 K. Also observed was a pseudogap of about 28 meV at the Fermi level at 4.2 K. Surprisingly, no charge density wave transitions were observed in two-layer and multi-layer TiTe2, despite the quasi-two-dimensional nature of the material in the bulk. The unique charge density wave phenomenon in the single layer raises intriguing questions that challenge the prevailing thinking about the mechanisms of charge density wave formation.Due to reduced dimensionality, the properties of 2D materials are often different from their 3D counterparts. Here, the authors identify the emergence of a unique charge density wave (CDW) order in monolayer TiTe2 that challenges the current understanding of CDW formation.

Association of New-Onset Diabetes Mellitus in Older People and Mortality in Taiwan: A 10-Year Nationwide Population-Based Study.

OBJECTIVE: Older patients with diabetes mellitus are at a higher risk of developing diabetic macro- and micro-vascular complications and cardiovascular diseases than younger diabetes mellitus patients. However, older diabetes mellitus patients are very heterogeneous in their clinical characteristics, diabetes mellitus-related complications and age at disease onset. This study aimed to evaluate the all-cause mortality rates and adverse health outcomes among older adults with new-onset diabetes mellitus through a nationwide population-based study. DESIGN: A retrospective cohort study. SETTING: 2001-2011 data of the National Health Insurance database. POPULATION: Nationally representative sample of Taiwanese adults aged 65 years and older with propensity score-matched controls. MAIN OUTCOME MEASURES: All-cause mortality and adverse health outcomes. RESULTS: During the study period, 45.3% of patients in the diabetes mellitus cohort and 38.8% in the non-diabetes mellitus cohort died. The adjusted relative risk for mortality in the diabetes mellitus cohort compared to the non-diabetes mellitus cohort was 1.23 (95% Confidence Interval [CI]=1.16-1.30) for males and 1.27 (95%CI=1.19-1.35) for females. During the follow-up period, 8.9% of the diabetes mellitus cohort and 5.8% of the non-diabetes mellitus cohort developed cardiovascular diseases; the diabetes mellitus cohort had an adjusted relative risk of cardiovascular complications compared to the non-diabetes mellitus cohort of 1.54 (95%CI=1.36-1.75) for men and 1.70 (95%CI=1.43-2.02) for women. The adjusted relative risk of mortality in the patients with hypoglycemia compared to non-hypoglycemia patients in the diabetes mellitus cohort was 2.33 (95%CI=1.81-3.01) for men and 2.73 (95%CI=2.10-3.52) for women after adjustment for age, Charlson comorbidity index, acute coronary syndrome, respiratory disease, cancer, infectious disease and nervous system disease at baseline. CONCLUSIONS: New-onset diabetes in older adults is associated with an increased risk of mortality, and hypoglycemia is an important marker of this association. Individualized care plans stratified by age at onset, duration of disease, comorbidity and functional status, as well as hypoglycemia avoidance, would benefit the management of diabetes in older adults.

Hidden Order and Dimensional Crossover of the Charge Density Waves in TiSe2.

Charge density wave (CDW) formation, a key physics issue for materials, arises from interactions among electrons and phonons that can also lead to superconductivity and other competing or entangled phases. The prototypical system TiSe2, with a particularly simple (2 × 2 × 2) transition and no Kohn anomalies caused by electron-phonon coupling, is a fascinating but unsolved case after decades of research. Our angle-resolved photoemission measurements of the band structure as a function of temperature, aided by first-principles calculations, reveal a hitherto undetected but crucial feature: a (2 × 2) electronic order in each layer sets in at ~232 K before the widely recognized three-dimensional structural order at ~205 K. The dimensional crossover, likely a generic feature of such layered materials, involves renormalization of different band gaps in two stages.

Dimensional Effects on the Charge Density Waves in Ultrathin Films of TiSe2.

Charge density wave (CDW) formation in solids is a critical phenomenon involving the collective reorganization of the electrons and atoms in the system into a wave structure, and it is expected to be sensitive to the geometric constraint of the system at the nanoscale. Here, we study the CDW transition in TiSe2, a quasi-two-dimensional layered material, to determine the effects of quantum confinement and changing dimensions in films ranging from a single layer to multilayers. Of key interest is the characteristic length scale for the transformation from a two-dimensional case to the three-dimensional limit. Angle-resolved photoemission spectroscopy (ARPES) measurements of films with thicknesses up to six layers reveal substantial variations in the energy structure of discrete quantum well states; however, the temperature-dependent band gap renormalization converges at just three layers. The results indicate a layer-dependent mixture of two transition temperatures and a very-short-range CDW interaction within a three-dimensional framework.

Charge density wave transition in single-layer titanium diselenide.

A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene-a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering. The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The observed Bardeen-Cooper-Schrieffer (BCS) behaviour of the gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk.

Saturation of the biological response to orthodontic forces and its effect on the rate of tooth movement.

OBJECTIVES: Investigate the expression and activity of inflammatory markers in response to different magnitudes of orthodontic forces and correlate this response with other molecular and cellular events during orthodontic tooth movement. SETTING AND SAMPLE POPULATION: CTOR Laboratory; 245 Sprague Dawley male rats. METHODS AND MATERIALS: Control, sham, and 5 different experimental groups received different magnitudes of force on the right maxillary first molar using a coil spring. In the sham group, the spring was not activated. Control group did not receive any appliance. At days 1, 3, 7, 14, and 28, the maxillae were collected for RNA and protein analysis, immunohistochemistry, and micro-CT. RESULTS: There was a linear relation between the force and the level of cytokine expression at lower magnitudes of force. Higher magnitudes of force did not increase the expression of cytokines. Activity of CCL2, CCL5, IL-1, TNF-α, RANKL, and number of osteoclasts reached a saturation point in response to higher magnitudes of force, with unchanged rate of tooth movement. CONCLUSION: After a certain magnitude of force, there is a saturation in the biological response, and higher forces do not increase inflammatory markers, osteoclasts, nor the amount of tooth movement. Therefore, higher forces to accelerate the rate of tooth movement are not justified.

Coupled Dirac fermions and neutrino-like oscillations in twisted bilayer graphene.

The low-energy quasiparticles in graphene can be described by a Dirac-Weyl Hamiltonian for massless fermions, hence graphene has been proposed to be an effective medium to study exotic phenomena originally predicted for relativistic particle physics, such as Klein tunneling and Zitterbewegung. In this work, we show that another important particle-physics phenomenon, the neutrino oscillation, can be studied and observed in a particular graphene system, namely, twisted bilayer graphene. It has been found that graphene layers grown epitaxially on SiC or by the chemical vapor deposition method on metal substrates display a stacking pattern with adjacent layers rotated by an angle with respect to each other. The quasiparticle states in two distinct graphene layers act as neutrinos with two flavors, and the interlayer interaction between them induces an appreciable coupling between these two "flavors" of massless fermions, leading to neutrino-like oscillations. In addition, our calculation shows that anisotropic transport properties manifest in a specific energy window, which is accessible experimentally in twisted bilayer graphene. Combining two graphene layers enables us to probe the rich physics involving multiple interacting Dirac fermions.

Promoting access to innovation for frail old persons. IAGG (International Association of Gerontology and Geriatrics), WHO (World Health Organization) and SFGG (Société Française de Gériatrie et de Gérontologie) Workshop--Athens January 20-21, 2012.

UNLABELLED: Frailty tends to be considered as a major risk for adverse outcomes in older persons, but some important aspects remain matter of debate. OBJECTIVES: The purpose of this paper is to present expert's positions on the main aspects of the frailty syndrome in the older persons. PARTICIPANTS: Workshop organized by International Association of Gerontology and Geriatrics (IAGG), World Health Organization (WHO) and Société Française de Gériatrie et de Gérontologie (SFGG). RESULTS: Frailty is widely recognized as an important risk factor for adverse health outcomes in older persons. This can be of particular value in evaluating non-disabled older persons with chronic diseases but today no operational definition has been established. Nutritional status, mobility, activity, strength, endurance, cognition, and mood have been proposed as markers of frailty. Another approach calculates a multidimensional score ranging from "very fit" to "severely frail", but it is difficult to apply into the medical practice. Frailty appears to be secondary to multiple conditions using multiple pathways leading to a vulnerability to a stressor. Biological (inflammation, loss of hormones), clinical (sarcopenia, osteoporosis etc.), as well as social factors (isolation, financial situation) are involved in the vulnerability process. In clinical practice, detection of frailty is of major interest in oncology because of the high prevalence of cancer in older persons and the bad tolerance of the drug therapies. Presence of frailty should also be taken into account in the definition of the cardiovascular risks in the older population. The experts of the workshop have listed the points reached an agreement and those must to be a priority for improving understanding and use of frailty syndrome in practice. CONCLUSION: Frailty in older adults is a syndrome corresponding to a vulnerability to a stressor. Diagnostic tools have been developed but none can integrate at the same time the large spectrum of factors and the simplicity asked by the clinical practice. An agreement with an international common definition is necessary to develop screening and to reduce the morbidity in older persons.

Quantum Monte Carlo investigations of adsorption energetics on graphene.

We have performed calculations of adsorption energetics on the graphene surface using the state-of-the-art diffusion quantum Monte Carlo method. Two types of configurations are considered in this work: the adsorption of a single O, F, or H atom on the graphene surface and the H-saturated graphene system (graphane). The adsorption energies are compared with those obtained from density functional theory with various exchange-correlation functionals. The results indicate that the approximate exchange-correlation functionals significantly overestimate the binding of O and F atoms on graphene, although the preferred adsorption sites are consistent. The energy errors are much less for atomic hydrogen adsorbed on the surface. We also find that a single O or H atom on graphene has a higher energy than in the molecular state, while the adsorption of a single F atom is preferred over the gas phase. In addition, the energetics of graphane is reported. The calculated equilibrium lattice constant turns out to be larger than that of graphene, at variance with a recent experimental suggestion.

Fractal Landau-level spectra in twisted bilayer graphene.

The Hofstadter butterfly spectrum for Landau levels in a two-dimensional periodic lattice is a rare example exhibiting fractal properties in a truly quantum system. However, the observation of this physical phenomenon in a conventional material will require a magnetic field strength several orders of magnitude larger than what can be produced in a modern laboratory. It turns out that for a specific range of rotational angles twisted bilayer graphene serves as a special system with a fractal energy spectrum under laboratory accessible magnetic field strengths. This unique feature arises from an intriguing electronic structure induced by the interlayer coupling. Using a recursive tight-binding method, we systematically map out the spectra of these Landau levels as a function of the rotational angle. Our results give a complete description of LLs in twisted bilayer graphene for both commensurate and incommensurate rotational angles and provide quantitative predictions of magnetic field strengths for observing the fractal spectra in these graphene systems.

Charge transport through graphene junctions with wetting metal leads.

Graphene is believed to be an excellent candidate material for next-generation electronic devices. However, one needs to take into account the nontrivial effect of metal contacts in order to precisely control the charge injection and extraction processes. We have performed transport calculations for graphene junctions with wetting metal leads (metal leads that bind covalently to graphene) using nonequilibrium Green's functions and density functional theory. Quantitative information is provided on the increased resistance with respect to ideal contacts and on the statistics of current fluctuations. We find that charge transport through the studied two-terminal graphene junction with Ti contacts is pseudo-diffusive up to surprisingly high energies.

Impact of interleukin-8 gene polymorphisms and environmental factors on oral cancer susceptibility in Taiwan.

OBJECTIVES: Interleukin-8 (IL-8), which is an angiogenic chemokine with a high expression level in tumor tissues, plays important roles in developing many human malignancies including oral squamous cell carcinoma (OSCC). This study was designed to examine the association of IL-8 gene polymorphisms with the susceptibility and clinicopathological characteristics of OSCC. METHODS: A total of 270 patients with OSCC and 350 healthy control subjects were recruited. Four single nucleotide polymorphisms (SNPs) of IL-8 genes were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping analysis. RESULTS: Results showed that four IL-8 SNPs (-251 T/A, +781 C/T, +1633 C/T, and +2767 A/T) were not associated with oral cancer susceptibility as well as clinicopathological parameters. But among 345 smokers, IL-8 polymorphisms carriers with betel quid chewing were found to have a 17.41- to 23.14-fold risk to have oral cancer compared to IL-8 wild-type carriers without betel quid chewing. Among 262 betel quid chewers, IL-8 polymorphisms carriers with smoking have a 10.54- to 20.44-fold risk to have oral cancer compared to those who carried wild type without smoking. CONCLUSIONS: Our results suggest that the combination of IL-8 gene polymorphisms and environmental carcinogens might be highly related to the risk of oral cancer.