Strictly One-Dimensional Electron System in Au Chains on Ge(001) Revealed By Photoelectron K-Space Mapping

Atomic nanowires formed by Au on Ge(001) are scrutinized for the band topology of the conduction electron system by k-resolved photoemission. Two metallic electron pockets are observed. Their Fermi surface sheets form straight lines without undulations perpendicular to the chains within experimental uncertainty. The electrons hence emerge as strictly confined to one dimension. Moreover, the system is stable against a Peierls distortion down to 10 K, lending itself for studies of the spectral function. Indications for unusually low spectral weight at the chemical potential are discussed.Comment: 4 pages, 4 figures - revised version with added Fig. 2e) and additional reference

Anderson Transition in Disordered Graphene

We use the regularized kernel polynomial method (RKPM) to numerically study the effect disorder on a single layer of graphene. This accurate numerical method enables us to study very large lattices with millions of sites, and hence is almost free of finite size errors. Within this approach, both weak and strong disorder regimes are handled on the same footing. We study the tight-binding model with on-site disorder, on the honeycomb lattice. We find that in the weak disorder regime, the Dirac fermions remain extended and their velocities decrease as the disorder strength is increased. However, if the disorder is strong enough, there will be a {\em mobility edge} separating {\em localized states around the Fermi point}, from the remaining extended states. This is in contrast to the scaling theory of localization which predicts that all states are localized in two-dimensions (2D).Comment: 4 page

US-LHC Magnet Database and conventions

The US-LHC Magnet Database is designed for production-magnet quality assurance, field and alignment error impact analysis, cryostat assembly assistance, and ring installation assistance. The database consists of tables designed to store magnet field and alignment measurements data and quench data. This information will also be essential for future machine operations including local IR corrections. (7 refs)

High mobility in a van der Waals layered antiferromagnetic metal

Magnetic van der Waals (vdW) materials have been heavily pursued for fundamental physics as well as for device design. Despite the rapid advances, so far magnetic vdW materials are mainly insulating or semiconducting, and none of them possesses a high electronic mobility - a property that is rare in layered vdW materials in general. The realization of a magnetic high-mobility vdW material would open the possibility for novel magnetic twistronic or spintronic devices. Here we report very high carrier mobility in the layered vdW antiferromagnet GdTe3. The electron mobility is beyond 60,000 cm2 V-1 s-1, which is the highest among all known layered magnetic materials, to the best of our knowledge. Among all known vdW materials, the mobility of bulk GdTe3 is comparable to that of black phosphorus, and is only surpassed by graphite. By mechanical exfoliation, we further demonstrate that GdTe3 can be exfoliated to ultrathin flakes of three monolayers, and that the magnetic order and relatively high mobility is retained in approximately 20-nm-thin flakes

Associations Between Covid-19-Related Threat, Stress, and Smoking in UK Adults Aged Under- and Over-30.

It has been suggested that smoking and age are associated with higher vulnerability to Covid-19. While threat of Covid-19 may reduce or stop smoking, increased stress due to lockdown could increase smoking behaviour. This study aimed to investigate changes in smoking behaviour in relation to age, Covid-19-related threat and subjective perceived stress during the UK lockdown. A cross-sectional study was performed. Online adverts were used to recruit UK residents who smoked combustible tobacco any time from January 2020. A questionnaire measured demographic information, smoking behaviour pre- and during-lockdown, perceived subjective stress (PSS), and Covid-19 related threat. Data were collected from a total of 145 participants (58% women, 39% men, 3% non-binary; mean age: 26 years, SD = 7.7), during UK lockdown between 22nd May and 22nd June 2020. Independent of stress and Covid-19-related threat, smoking was reduced in those aged less than 30 years. In participants aged 30 and above, increases in smoking behaviour were associated with higher PSS. The results highlight the relevance of the different stages of life on the relationship between stress, threat, and smoking behaviour. Greater emphasis should be placed on stress reduction for adult smokers aged 30 and above to enable smoking cessation

How has COVID-19 lockdown impacted smoking? A thematic analysis of written accounts from UK smokers.

Objective. This study was designed to investigate UK smokers' accounts of impacts of COVID-19 on their smoking, to develop implications for supporting smoking cessation. Design. One hundred and thirty-two smokers aged 19-52 years (mean age 25 years), recruited through an advert distributed through social media and a dedicated Twitter page, completed an anonymous online questionnaire. Main Outcome Measures. Smokers produced written accounts of how COVID-19 had impacted their smoking. Responses were of unlimited length and completed online 22nd May-22nd June 2020 during UK COVID-19 lockdown. Results. Inductive thematic analysis generated three themes: i) increased smoking as a coping mechanism to deal with anxiety, boredom, stress, and anger in COVID-19 lockdown; ii) lockdown as enabling quitting through lifting social barriers and enabling a focus on health benefits; and iii) no change, avoiding Government/media COVID-19 information due to disbelief, lack of trust, and perceptions of bias. Conclusions. Results demonstrate a need for credible public health messaging on COVID-19 risk aimed at smokers. Implications for supporting smoking cessation are discussed, including maintaining quitting in those "social smokers" who quit during lockdown, and support on stress-management and emotion regulation in those who use smoking as a way to cope with stress, anger, and boredom

Controlling the balance between remote, pinhole, and van der Waals epitaxy of Heusler films on graphene/sapphire

Remote epitaxy on monolayer graphene is promising for synthesis of highly lattice mismatched materials, exfoliation of free-standing membranes, and re-use of expensive substrates. However, clear experimental evidence of a remote mechanism remains elusive. In many cases, due to contaminants at the transferred graphene/substrate interface, alternative mechanisms such as pinhole-seeded lateral epitaxy or van der Waals epitaxy can explain the resulting exfoliatable single-crystalline films. Here, we find that growth of the Heusler compound GdPtSb on clean graphene on sapphire substrates produces a 30 degree rotated epitaxial superstructure that cannot be explained by pinhole or van der Waals epitaxy. With decreasing growth temperature the volume fraction of this 30 degree domain increases compared to the direct epitaxial 0 degree domain, which we attribute to slower surface diffusion at low temperature that favors remote epitaxy, compared to faster surface diffusion at high temperature that favors pinhole epitaxy. We further show that careful graphene/substrate annealing ($T\sim 700 ^\circ C$) and consideration of the film/substrate vs film/graphene lattice mismatch are required to obtain epitaxy to the underlying substrate for a variety of other Heusler films, including LaPtSb and GdAuGe. The 30 degree rotated superstructure provides a possible experimental fingerprint of remote epitaxy since it is inconsistent with the leading alternative mechanisms

Formation primaquine-5, 6-orthoquinone, the putative active and toxic metabolite of primaquine via direct oxidation in human erythrocytes

Copyright © 2019 by The American Society for Pharmacology and Experimental Therapeutics Short precorneal residence time and poor transocular membrane permeability are the major challenges associated with topical ocular drug delivery. In the present research, the efficiency of the electrolyte-triggered sol-to-gel-forming system of natamycin (NT) transfersomes was investigated for enhanced and prolonged ophthalmic delivery. Transfersomes were optimized by varying the molar ratios of phospholipid, sorbitan monostearate (Span) and tocopheryl polyethylene glycol succinate (TPGS). NT transfersome formulations (FNs) prepared with a 1:1 molar ratio of phospholipid-to-Span and low levels of TPGS showed optimal morphometric properties, and were thus selected to fabricate the in situ gelling system. Gellan gum-based (0.3% w/v) FN-loaded formulations (FNGs) immediately formed an in situ gel in the simulated tear fluid, with considerable viscoelastic characteristics. In vitro cytotoxicity in corneal epithelial cells and corneal histology studies demonstrated the ocular safety and cytocom-patibility of these optimized formulations. Transcorneal permeability of NT from these formulations was significantly higher than in the control suspension. Moreover, the ocular disposition studies of NT, from the FNs and FNGs, in New Zealand male albino rabbits demonstrated the superiority of the electrolyte-sensitive FNGs in terms of NT delivery to the ocular tissues