Exploring the Charge Density Wave Phase of 1T-TaSe_{2}: Mott or Charge-Transfer Gap?

1T-TaSe_{2} is widely believed to host a Mott metal-insulator transition in the charge density wave (CDW) phase according to the spectroscopic observation of a band gap that extends across all momentum space. Previous investigations inferred that the occurrence of the Mott phase is limited to the surface only of bulk specimens, but recent analysis on thin samples revealed that the Mott-like behavior, observed in the monolayer, is rapidly suppressed with increasing thickness. Here, we report combined time- and angle-resolved photoemission spectroscopy and theoretical investigations of the electronic structure of 1T-TaSe_{2}. Our experimental results confirm the existence of a state above E_{F}, previously ascribed to the upper Hubbard band, and an overall band gap of ∼0.7 eV at Γ[over ¯]. However, supported by density functional theory calculations, we demonstrate that the origin of this state and the gap rests on band structure modifications induced by the CDW phase alone, without the need for Mott correlation effects.

High-efficiency, fifth-harmonic generation of a joule-level neodymium laser in a large-aperture ammonium dihydrogen phosphate crystal.

High-energy deep ultraviolet (UV) sources are required for high-density plasma diagnostics. The fifth-harmonic generation of large-aperture neodymium lasers in ammonium dihydrogen phosphate (ADP) can significantly increase UV energies due to the availability of large ADP crystals. Noncritical phase matching in ADP for (ω + 4ω) was achieved by cooling a 65 × 65-mm crystal in a two-chamber cryostat to 200 K. The crystal chamber used helium as the thermally conductive medium between the crystal and the crystal chamber, which was surrounded by a high-vacuum chamber with a liquid nitrogen reservoir. A temperature variation of 0.2 K across the crystal aperture was obtained. The total conversion efficiency from the fundamental to the fifth harmonic at 211 nm was 26%.

Photoemission from non-polar aromatic molecules in the gas and liquid phase.

The photoelectron spectra of both liquid and gas phase aromatic molecules are reported. The spectra were obtained using a 34.1 eV source produced by high harmonic generation and analysed with the help of high-level ab initio simulations using the reflection principle combined with path integral molecular dynamics simulations accounting for nuclear quantum effects for the gas phase. We demonstrate the suitability of three trimethylbenzenes (1,3,5-trimethylbenzene, 1,2,3-trimethylbenzene and 1,2,4-trimethylbenzene) as a solvent for liquid photoelectron spectroscopy of solute species. We also discuss the electrokinetic charging of a non-polar liquid jet.

Non-host larvae negatively impact persistence of the entomopathogen Beauveria bassiana in soil.

A better understanding of the ecology of the insect pathogenic fungus, Beauveria bassiana, in soil is needed to identify reasons behind the variable efficacy often seen after field application. A transformed strain of a candidate commercial strain of B. bassiana (F418 gfp tr3), expressing the green fluorescent protein and the hygromycin B resistance gene, was used to assess the effects of the larvae of a host insect, Tenebrio molitor L. (Coleoptera: Tenebrionidae), a non-host, Costelytra zealandica (Coleoptera: Scarabaeidae) and the absence of larvae on the persistence of F418 gfp tr3 in pasteurised and non-sterile soil over 4 months. In the presence of a T. molitor larvae, F418 gfp tr3 populations increased significantly in pasteurised and non-sterile soil; however, populations increased less in non-sterile soil than in pasteurised soil. Lower populations of F418 gfp tr3 were recovered in pasteurised soil in the presence of C. zealandica larvae than in pasteurised soil without larvae. No difference was observed between F418 gfp tr3 populations in non-sterile soil with a non-host larvae or without larvae. Accompanying studies showed that F418 gfp tr3 conidia germinated and produced appressoria on live and excised cuticle of non-host (C. zealandica) larvae but infection did not occur, leading to a net loss of viable conidia in the soil. Conidia administrated orally to C. zealandica larvae were viable on recovery from faecal samples, suggesting that ingestion of the fungus by the larvae had little impact on the viable fungal population. Soil bacterial and fungal community patterns were analysed using Single-Strand Conformation Polymorphism (SSCP) and showed a correlation between changes in F418 gfp tr3 persistence in pasteurised and non-sterile soil and changes in soil communities in the presence of a host insect, non-host insect or in the absence of insect. In pasteurised soil, non-specific germination of F418 gfp tr3 conidia on the non-host larval cuticle and the presence of antagonistic bacteria introduced with the field-collected larvae are most likely responsible for the differences observed. The more complex microbial community structures in non-sterile soil could lead to fungistasis, preventing potentially antagonistic bacteria degrading conidia or inhibiting attachment and germination on the non-host larval cuticle, resulting in the observed lack of difference between non-host and no larval treatments.

Publisher's Note: Hydrogen Bonds in Excited State Proton Transfer [Phys. Rev. Lett. 117, 163002 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.117.163002.

Investigating the Pygmy Dipole Resonance Using ß Decay.

In this contribution it is explored whether γ-ray spectroscopy following ß decay with high Q values from mother nuclei with low ground-state spin can be exploited as a probe for the pygmy dipole resonance. The suitability of this approach is demonstrated by a comparison between data from photon scattering, ^{136}Xe(γ,γ^{'}), and ^{136}I [J_{0}^{π}=(1^{-})]→^{136}Xe^{*} ß-decay data. It is demonstrated that ß decay populates 1^{-} levels associated with the pygmy dipole resonance, but only a fraction of those. The complementary insight into the wave functions probed by ß decay is elucidated by calculations within the quasiparticle phonon model. It is demonstrated that ß decay dominantly populates complex configurations, which are only weakly excited in inelastic scattering experiments.

Hydrogen Bonds in Excited State Proton Transfer.

Hydrogen bonding interactions between biological chromophores and their surrounding protein and solvent environment significantly affect the photochemical pathways of the chromophore and its biological function. A common first step in the dynamics of these systems is excited state proton transfer between the noncovalently bound molecules, which stabilizes the system against dissociation and principally alters relaxation pathways. Despite such fundamental importance, studying excited state proton transfer across a hydrogen bond has proven difficult, leaving uncertainties about the mechanism. Through time-resolved photoelectron imaging measurements, we demonstrate how the addition of a single hydrogen bond and the opening of an excited state proton transfer channel dramatically changes the outcome of a photochemical reaction, from rapid dissociation in the isolated chromophore to efficient stabilization and ground state recovery in the hydrogen bonded case, and uncover the mechanism of excited state proton transfer at a hydrogen bond, which follows sequential hydrogen and charge transfer processes.

Generation and Evolution of Spin-, Valley-, and Layer-Polarized Excited Carriers in Inversion-Symmetric WSe_{2}.

We report the spin-selective optical excitation of carriers in inversion-symmetric bulk samples of the transition metal dichalcogenide (TMDC) WSe_{2}. Employing time- and angle-resolved photoelectron spectroscopy (trARPES) and complementary time-dependent density functional theory (TDDFT), we observe spin-, valley-, and layer-polarized excited state populations upon excitation with circularly polarized pump pulses, followed by ultrafast (<100 fs) scattering of carriers towards the global minimum of the conduction band. TDDFT reveals the character of the conduction band, into which electrons are initially excited, to be two-dimensional and localized within individual layers, whereas at the minimum of the conduction band, states have a three-dimensional character, facilitating interlayer charge transfer. These results establish the optical control of coupled spin-, valley-, and layer-polarized states in centrosymmetric materials with locally broken symmetries and suggest the suitability of TMDC multilayer and heterostructure materials for valleytronic and spintronic device concepts.

Outdoor, indoor, and personal black carbon exposure from cookstoves burning solid fuels.

Black carbon (BC) emissions from solid fuel combustion are associated with increased morbidity and mortality and are important drivers of climate change. We studied BC measurements, approximated by particulate matter (PM2.5 ) absorbance, in rural Yunnan province, China, whose residents use a variety of solid fuels for cooking and heating including bituminous and anthracite coal, and wood. Measurements were taken over two consecutive 24-h periods from 163 households in 30 villages. PM2.5 absorbance (PMabs ) was measured using an EEL 043 Smoke Stain Reflectometer. PMabs measurements were higher in wood burning households (16.3 × 10(-5) /m) than bituminous and anthracite coal households (12 and 5.1 × 10(-5) /m, respectively). Among bituminous coal users, measurements varied by a factor of two depending on the coal source. Portable stoves (which are lit outdoors and brought indoors for use) were associated with reduced PMabs levels, but no other impact of stove design was observed. Outdoor measurements were positively correlated with and approximately half the level of indoor measurements (r = 0.49, P < 0.01). Measurements of BC (as approximated by PMabs ) in this population are modulated by fuel type and source. This provides valuable insight into potential morbidity, mortality, and climate change contributions of domestic usage of solid fuels.

Indoor concentrations of nitrogen dioxide and sulfur dioxide from burning solid fuels for cooking and heating in Yunnan Province, China.

The Chinese national pollution census has indicated that the domestic burning of solid fuels is an important contributor to nitrogen dioxide (NO2 ) and sulfur dioxide (SO2 ) emissions in China. To characterize indoor NO2 and SO2 air concentrations in relation to solid fuel use and stove ventilation in the rural counties of Xuanwei and Fuyuan, in Yunnan Province, China, which have among the highest lung cancer rates in the nation, a total of 163 participants in 30 selected villages were enrolled. Indoor 24-h NO2 and SO2 samples were collected in each household over two consecutive days. Compared to smoky coal, smokeless coal use was associated with higher NO2 concentrations [geometric mean (GM) = 132 µg/m(3) for smokeless coal and 111 µg/m(3) for smoky coal, P = 0.065] and SO2 [limit of detection = 24 µg/m(3) ; percentage detected (%Detect) = 86% for smokeless coal and 40% for smoky coal, P < 0.001]. Among smoky coal users, significant variation of NO2 and SO2 air concentrations was observed across different stove designs and smoky coal sources in both counties. Model construction indicated that the measurements of both pollutants were influenced by stove design. This exposure assessment study has identified high levels of NO2 and SO2 as a result of burning solid fuels for cooking and heating.

Using Deception to Establish a Reproducible Improvement in 4-Km Cycling Time Trial Performance.

We investigated whether performance gains achieved with deception persisted after the deception was revealed, and whether pacing strategy changed. 14 trained cyclists completed 4 simulated 4-km time trials (TT) on a cycle ergometer comprising familiarization and baseline trials (BAS), followed by "unaware" (of deception, UAW) and "aware" (of deception, AW) trials on separate days. In the UAW trial, participants competed against an on-screen avatar set at 102% of their baseline trial mean power output (Pmean) believing it was set at 100% of BAS Pmean. 24 h prior to the AW trial, participants were informed of the deception in the UAW trial. 4 participants did not improve in the UAW trial compared to BAS. 10 participants improved time to completion (TTC) and Pmean in the UAW and AW trials compared to BAS (p<0.03) with no significant differences between UAW and AW (p=1.0). Pacing strategy (at 0.5-km intervals) and RPE responses were unchanged (p>0.05) for these participants. In summary, deception did not improve performance in all participants. However, participants whose time trial performance improved following deception could retain their performance gains once the deception was revealed, demonstrating a similar pacing strategy and RPE response.

The Effect of Inspiratory Muscle Training on Respiratory and Limb Locomotor Muscle Deoxygenation During Exercise with Resistive Inspiratory Loading.

We investigated how inspiratory muscle training impacted respiratory and locomotor muscle deoxygenation during submaximal exercise with resistive inspiratory loading. 16 male cyclists completed 6 weeks of either true (n=8) or sham (n=8) inspiratory muscle training. Pre- and post-training, subjects completed 3, 6-min experimental trials performed at ~80% ˙VO2peak with interventions of either moderate inspiratory loading, heavy inspiratory loading, or maximal exercise imposed in the final 3 min. Locomotor and respiratory muscle oxy-, deoxy-, and total-haemoglobin and myoglobin concentration was continuously monitored using near-infrared spectroscopy. Locomotor muscle deoxygenation changes from 80% ˙VO2peak to heavy inspiratory loading were significantly reduced pre- to post-training from 4.3±5.6 µM to 2.7±4.7 µM. Respiratory muscle deoxygenation was also significantly reduced during the heavy inspiratory loading trial (4.6±3.5 µM to 1.9±1.5 µM) post-training. There was no significant difference in oxy-, deoxy-, or total-haemoglobin and myoglobin during any of the other loading trials, from pre- to post-training, in either group. After inspiratory muscle training, highly-trained cyclists exhibited decreased locomotor and respiratory muscle deoxygenation during exercise with heavy inspiratory loading. These data suggest that inspiratory muscle training reduces oxygen extraction by the active respiratory and limb muscles, which may reflect changes in respiratory and locomotor muscle oxygen delivery.

Increased function of pronociceptive TRPV1 at the level of the joint in a rat model of osteoarthritis pain.

OBJECTIVES: Blockade of transient receptor potential vanilloid 1 (TRPV1) with systemic antagonists attenuates osteoarthritis (OA) pain behaviour in rat models, but on-target-mediated hyperthermia has halted clinical trials. The present study investigated the potential for targeting TRPV1 receptors within the OA joint in order to produce analgesia. METHODS: The presence of TRPV1 receptors in human synovium was detected using western blotting and immunohistochemistry. In a rat model of OA, joint levels of an endogenous ligand for TRPV1, 12-hydroxy-eicosatetraenoic acid (12-HETE), were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Effects of peripheral administration of the TRPV1 receptor antagonist JNJ-17203212 on afferent fibre activity, pain behaviour and core body temperature were investigated. Effects of a spinal administration of JNJ-17203212 on dorsal horn neuronal responses were studied. RESULTS: We demonstrate increased TRPV1 immunoreactivity in human OA synovium, confirming the diseased joint as a potential therapeutic target for TRPV1-mediated analgesia. In a model of OA pain, we report increased joint levels of 12-HETE, and the sensitisation of joint afferent neurones to mechanical stimulation of the knee. Local administration of JNJ-17203212 reversed this sensitisation of joint afferents and inhibited pain behaviour (weight-bearing asymmetry), to a comparable extent as systemic JNJ-17203212, in this model of OA pain, but did not alter core body temperature. There was no evidence for increased TRPV1 function in the spinal cord in this model of OA pain. CONCLUSIONS: Our data provide a clinical and mechanistic rationale for the future investigation of the therapeutic benefits of intra-articular administration of TRPV1 antagonists for the treatment of OA pain.

Tracking Primary Thermalization Events in Graphene with Photoemission at Extreme Time Scales.

Direct and inverse Auger scattering are amongst the primary processes that mediate the thermalization of hot carriers in semiconductors. These two processes involve the annihilation or generation of an electron-hole pair by exchanging energy with a third carrier, which is either accelerated or decelerated. Inverse Auger scattering is generally suppressed, as the decelerated carriers must have excess energies higher than the band gap itself. In graphene, which is gapless, inverse Auger scattering is, instead, predicted to be dominant at the earliest time delays. Here, <8 fs extreme-ultraviolet pulses are used to detect this imbalance, tracking both the number of excited electrons and their kinetic energy with time-and angle-resolved photoemission spectroscopy. Over a time window of approximately 25 fs after absorption of the pump pulse, we observe an increase in conduction band carrier density and a simultaneous decrease of the average carrier kinetic energy, revealing that relaxation is in fact dominated by inverse Auger scattering. Measurements of carrier scattering at extreme time scales by photoemission will serve as a guide to ultrafast control of electronic properties in solids for petahertz electronics.

Type 1 autoimmune pancreatitis and IgG4-related sclerosing cholangitis is associated with extrapancreatic organ failure, malignancy, and mortality in a prospective UK cohort.

OBJECTIVES: Type I autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-related SC) are now recognized as components of a multisystem IgG4-related disease (IgG4-RD). We aimed to define the clinical course and long-term outcomes in patients with AIP/IgG4-SC recruited from two large UK tertiary referral centers. METHODS: Data were collected from 115 patients identified between 2004 and 2013, and all were followed up prospectively from diagnosis for a median of 33 months (range 1-107), and evaluated for response to therapy, the development of multiorgan involvement, and malignancy. Comparisons were made with national UK statistics. RESULTS: Although there was an initial response to steroids in 97%, relapse occurred in 50% of patients. IgG4-SC was an important predictor of relapse (P<0.01). Malignancy occurred in 11% shortly before or after the diagnosis of IgG4-RD, including three hepatopancreaticobiliary cancers. The risk of any cancer at diagnosis or during follow-up when compared with matched national statistics was increased (odds ratio=2.25, CI=1.12-3.94, P=0.02). Organ dysfunction occurred within the pancreas, liver, kidney, lung, and brain. Mortality occurred in 10% of patients during follow-up. The risk of death was increased compared with matched national statistics (odds ratio=2.07, CI=1.07-3.55, P=0.02). CONCLUSIONS: Our findings suggest that AIP and IgG4-SC are associated with significant morbidity and mortality owing to extrapancreatic organ failure and malignancy. Detailed clinical evaluation for evidence of organ dysfunction and associated malignancy is required both at first presentation and during long-term follow-up.

Injury prevention among friends: the benefits of school connectedness.

Unsafe road behaviors, violence and alcohol use, are primary contributors to adolescent injury. Research suggests that adolescents look out for their friends and engage in protective behavior to reduce others' risk-taking and that school connectedness is associated with reduced injury-risks. This study examined the role of school connectedness in willingness to protect and prevent friends from involvement in alcohol use, fights and unlicensed driving. Surveys were completed at two time points, six months apart, by 545 13-14 year olds from seven Australian high schools. Females were significantly more likely than males to report willingness to protect their friends. School connectedness significantly and positively predicted willingness to protect across all three injury-risk behaviors, after accounting for sex and own involvement in injury-risk behaviors. School connectedness may therefore be an important factor to target in school-based prevention programs, both to reduce adolescents' own injury-risk behavior and to increase injury prevention among friends.

Randomized clinical trial: macrogol/PEG 3350 plus electrolytes for treatment of patients with constipation associated with irritable bowel syndrome.

OBJECTIVES: Polyethylene glycol (PEG) 3350 plus electrolytes (PEG 3350+E) is an established treatment for constipation and has been proposed as a treatment option for constipation associated with irritable bowel syndrome (IBS-C). This study aimed to compare the efficacy and safety of PEG 3350+E vs. placebo in adult patients with IBS-C. METHODS: Following a 14-day run-in period without study medication, patients with confirmed IBS-C were randomized to receive PEG 3350+E (N=68) or placebo (N=71) for 28 days. The primary endpoint was the mean number of spontaneous bowel movements (SBMs) per day in the last treatment week. RESULTS: In both groups, mean weekly number of SBMs (±s.d.) increased from run-in. The difference between the groups in week 4 (PEG 3350+E, 4.40±2.581; placebo, 3.11±1.937) was statistically significant (95% confidence interval: 1.17, 1.95; P<0.0001). Although mean severity score for abdominal discomfort/pain was significantly reduced compared with run-in with PEG 3350+E, there was no difference vs. placebo. Spontaneous complete bowel movements, responder rates, stool consistency, and severity of straining also showed superior improvement in the PEG 3350+E group over placebo in week 4. The most common drug related treatment-emergent adverse events were abdominal pain (PEG 3350+E, 4.5%; placebo, 0%) and diarrhoea (PEG 3350+E, 4.5%; placebo, 4.3%). CONCLUSIONS: In IBS-C, PEG 3350+E was superior to placebo for relief of constipation, and although a statistically significant improvement in abdominal discomfort/pain was observed compared with baseline, there was no associated improvement compared with placebo. PEG 3350+E is a well-established and effective treatment that should be considered suitable for use in IBS-C.

Hepcidin levels in diabetes mellitus and polycystic ovary syndrome.

AIM: Increased body iron is associated with insulin resistance. Hepcidin is the key hormone that negatively regulates iron homeostasis. We hypothesized that individuals with insulin resistance have inadequate hepcidin levels for their iron load. METHODS: Serum concentrations of the active form of hepcidin (hepcidin-25) and hepcidin:ferritin ratio were evaluated in participants with Type 2 diabetes (n = 33, control subjects matched for age, gender and BMI, n = 33) and participants with polycystic ovary syndrome (n = 27, control subjects matched for age and BMI, n = 16). To investigate whether any changes observed were associated with insulin resistance rather than insulin deficiency or hyperglycaemia per se, the same measurements were made in participants with Type 1 diabetes (n = 28, control subjects matched for age, gender and BMI, n = 30). Finally, the relationship between homeostasis model assessment of insulin resistance and serum hepcidin:ferritin ratio was explored in overweight or obese participants without diabetes (n = 16). RESULTS: Participants with Type 2 diabetes had significantly lower hepcidin and hepcidin:ferritin ratio than control subjects (P < 0.05 and P < 0.01, respectively). Participants with polycystic ovary syndrome had a significantly lower hepcidin:ferritin ratio than control subjects (P < 0.05). There was no significant difference in hepcidin or hepcidin:ferritin ratio between participants with Type 1 diabetes and control subjects (P = 0.88 and P = 0.94). Serum hepcidin:ferritin ratio inversely correlated with homeostasis model assessment of insulin resistance (r = -0.59, P < 0.05). CONCLUSION: Insulin resistance, but not insulin deficiency or hyperglycaemia per se, is associated with inadequate hepcidin levels. Reduced hepcidin concentrations may cause increased body iron stores in insulin-resistant states.

Late immune tolerance induction in haemophilia A patients.

The incidence of inhibitor development in patients with severe haemophilia A is approximately 30%. Immune tolerance induction (ITI) is commonly utilized to eradicate these antibodies and is successful in 63-100% of cases. Potential predictors of a poor outcome in ITI include a high preinduction titre, high historical peak titre, older age at start of ITI and prolonged interval from diagnosis to start of ITI. The goal of this study was to characterize the outcomes of patients from our centre who have undergone late ITI, many of whom had poor prognostic features. Medical records of patients in our centre with severe/moderately severe haemophilia A (<2% FVIII activity) and history of inhibitor were reviewed. Data were abstracted from all patients who attempted late ITI. Nine patients underwent late ITI between January 1999 and December 2011. Within this cohort, 7 (78%) patients were black, 6 (67%) were <21 years old and 4 (44%) had a family history of inhibitor. Three patients had previously received ITI unsuccessfully. To date, 4 (44%) patients are tolerized (persistently negative inhibitor titre, FVIII recovery >66% and successfully treated with FVIII products ± FVIII t(½) of >6 h). Three patients are partially tolerized (have low responding inhibitor, variable FVIII recovery and successfully treated with FVIII products). Two patients are not tolerized. Some patients with haemophilia A and long-standing inhibitors may benefit from ITI.

The effect of propofol on patient reaction time and its relationship with loss of verbal contact before induction of anaesthesia.

Increasing the calculated plasma concentration of propofol has been shown to increase choice reaction time and visual and auditory response times. We studied the relationship of reaction to a vibrating handset as the effect-site target-controlled propofol concentration was incrementally increased in 20 patients during sedation, before induction of general anaesthesia. The reaction time increased, initially slowly and then more rapidly, as the calculated effect-site concentration of propofol increased, until the reaction to the vibrating handset was lost at a mean (SD) propofol effect-site concentration of 2.0 (0.6) µg.ml(-1) . The loss of response to verbal contact occurred at a propofol effect-site concentration of 2.4 (0.5) µg.ml(-1) . Reaction time may be of use clinically to warn of impending loss of verbal contact.