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The binding mechanism of gas molecules on material surfaces is essential for understanding adsorption and sensing performance. In the present study, we examine the interaction of some volatile organic compounds (VOCs), including HCHO, C 2 H 5 OH, and CH 3 COCH 3 , on pristine graphene and its Fe/Cu-adsorbed surfaces using first-principles calculations. The results indicate that the adsorption of these molecules on graphene is regarded as physisorption, while chemisorption is observed for Fe/Cu attached surfaces. The binding of sites on molecules and surfaces primarily involves hydrogen bonds for the pure form of graphene. In contrast, stable interactions occur at functional groups such as >CO, -OH with Fe/Cu atoms, as well as CC bonds of π-rings on modified structures of graphene. It is noticeable that stronger adsorption is observed in the case of Fe addition (Gr-Fe) compared to Cu (Gr-Cu), enhancing the gas adsorption and sensing performance on graphene. Remarkably, the graphene surfaces supported by Fe and Cu improved selectivity in detecting VOC molecules, particularly C 2 H 5 OH and CH 3 COCH 3 for Gr-Fe, and HCHO for Gr-Cu. Quantum chemical analyses reveal that the Fe/Cu⋯O/C contacts are covalent interactions, contributing significantly to the stability of configurations and sensing properties of Fe/Cu-adsorbed graphene. In summary, the observed improvements in selectivity, enhanced adsorption strength, and the identification of crucial interactions at the surface offer valuable insights into designing highly efficient gas sensors and developing advanced sensing materials.

Embedding rare-earth monopnictide nanoparticles into III-V semiconductors enables unique optical, electrical, and thermal properties for THz photoconductive switches, tunnel junctions, and thermoelectric devices. Despite the high structural quality and control over growth, particle size (<3 nm), and density, the underlying electronic structure of these nanocomposite materials has only been hypothesized. Structural and electronic properties of ErAs nanoparticles with different shapes and sizes (cubic to spherical, 1.14, 1.71, and 2.28 nm) in AlAs, GaAs, InAs, and their alloys are investigated using first-principles calculations, revealing that spherical nanoparticles have lower formation energies. For the lowest-energy nanoparticles, the Fermi level is pinned near midgap in GaAs and AlAs but resonant in the conduction band in InAs. The Fermi level is shifted down as the particle size increases and is pinned on an absolute energy scale considering the band alignment at AlAs/GaAs/InAs interfaces, offering insights into the rational design of these nanomaterials.

Thin films of rare-earth monopnictide (RE-V) semimetals are expected to turn into semiconductors due to quantum confinement effects (QCE), lifting the overlap between electron pockets at Brillouin zone edges (X) and hole pockets at the zone center (Γ). Instead, using LaSb as an example, we find the emergence of the quantum spin Hall (QSH) insulator phase in (001)-oriented films as the thickness is reduced to 7, 5, or 3 monolayers (MLs). This is attributed to a strong QCE on the in-plane electron pockets and the lack of quantum confinement on the out-of-plane pocket projected onto the zone center, resulting in a band inversion. Spin-orbit coupling (SOC) opens a sizable nontrivial gap in the band structure of ultrathin films. Such effect is anticipated to be general in rare-earth monopnictides and may lead to interesting phenomena when coupled with the 4 f magnetic moments present in other members of this family of materials.

In one-dimensional (1D) systems, electronic interactions lead to a breakdown of Fermi liquid theory and the formation of a Tomonaga-Luttinger Liquid (TLL). The strength of its many-body correlations can be quantified by a single dimensionless parameter, the Luttinger parameter K, characterising the competition between the electrons' kinetic and electrostatic energies. Recently, signatures of a TLL have been reported for the topological edge states of quantum spin Hall (QSH) insulators, strictly 1D electronic structures with linear (Dirac) dispersion and spin-momentum locking. Here we show that the many-body interactions in such helical Luttinger Liquid can be effectively controlled by the edge state's dielectric environment. This is reflected in a tunability of the Luttinger parameter K, distinct on different edges of the crystal, and extracted to high accuracy from the statistics of tunnelling spectra at tens of tunnelling points. The interplay of topology and many-body correlations in 1D helical systems has been suggested as a potential avenue towards realising non-Abelian parafermions., (© 2022. The Author(s).)

Terahertz (THz) technologies have been of interest for many years due to the variety of applications including gas sensing, nonionizing imaging of biological systems, security and defense, and so forth. To date, scientists have used different classes of materials to perform different THz functions. However, to assemble an on-chip THz integrated system, we must understand how to integrate these different materials. Here, we explore the growth of Bi 2 Se 3 , a topological insulator material that could serve as a plasmonic waveguide in THz integrated devices, on technologically important GaAs(001) substrates. We explore surface treatments and find that an atomically smooth GaAs surface is critical to achieving high-quality Bi 2 Se 3 films despite the relatively weak film/substrate interaction. Calculations indicate that the Bi 2 Se 3 /GaAs interface is likely selenium-terminated and shows no evidence of chemical bonding between the Bi 2 Se 3 and the substrate. These results are a guide for integrating van der Waals materials with conventional semiconductor substrates and serve as the first steps toward achieving an on-chip THz integrated system.

Interactions of dimethyl sulfoxide with carbon dioxide and water molecules which induce 18 significantly stable complexes are thoroughly investigated. An addition of CO 2 or H 2 O molecules into the DMSO⋯1CO 2 and DMSO⋯1H 2 O systems leads to an increase in the stability of the resulting complexes, in which it is larger for a H 2 O addition than a CO 2 . The overall stabilization energy of the DMSO⋯1,2CO 2 is mainly contributed by the S=O⋯C Lewis acid-base interaction, whereas the O - H⋯O hydrogen bond plays a significant role in stabilizing complexes of DMSO⋯1,2H 2 O and DMSO⋯1CO 2 ⋯1H 2 O. Remarkably, the complexes of DMSO⋯2H 2 O are found to be more stable than DMSO⋯1CO 2 ⋯1H 2 O and DMSO⋯2CO 2 . The level of the cooperativity of multiple interactions in ternary complexes tends to decrease in going from DMSO⋯2H 2 O to DMSO⋯1CO 2 ⋯1H 2 O and finally to DMSO⋯2CO 2 . It is generally found that the red shift of the O - H bond involved in an O - H⋯O hydrogen bond increases while the blue shift of a C - H bond in a C - H⋯O hydrogen bond decreases when a cooperative effect occurs in ternary complexes as compared to those of the corresponding binary complexes. © 2018 Wiley Periodicals, Inc., (© 2018 Wiley Periodicals, Inc.)

The purpose of this paper is to investigate the relationship between clinical outcome and the intactness of cagPAI in Helicobacter pylori strains from Vietnam. The presence or absence of 30 cagPAI genes was investigated by polymerase chain reaction (PCR) and dot-blotting. H. pylori-induced interleukin-8 secretion and hummingbird phenotype, and H. pylori adhesion to gastric epithelial cells were examined. The serum concentration of pepsinogen 1, pepsinogen 2, and gastrin was also measured in all patients. cagPAI was present in all 103 Vietnamese H. pylori isolates, of which 91 had intact cagPAI and 12 contained only a part of cagPAI. Infection with the partial cagPAI strains was less likely to be associated with peptic ulcer and chronic gastric mucosal inflammation than infection with strains possessing intact cagPAI. The partial cagPAI strains lacked almost all ability to induce interleukin-8 secretion and the hummingbird phenotype in gastric cells. Their adhesion to epithelial cells was significantly decreased in comparison with intact cagPAI strains. Moreover, for the first time, we found an association between cagPAI status and the serum concentration of pepsinogens 1 and 2 in infected patients. H. pylori strains with internal deletion within cagPAI are less virulent and, thus, less likely to be associated with severe clinical outcomes.

Purpose: This study attempted to assess the value of the RAPIRUN test for the diagnosis of Helicobacter pylori infection in the Vietnamese population., Methods: We recruited 148 Vietnamese patients undergoing upper gastrointestinal endoscopy during which five gastric biopsies were taken; blood and urine samples were collected from each patient. Helicobacter pylori infection status was determined by a combination of three different methods, including culture, immunohistochemistry, and serum ELISA. RAPIRUN tests were performed using urine samples., Results: The sensitivity, specificity, and accuracy of the RAPIRUN test in these Vietnamese patients were 79.5, 90.7, and 84.5%, respectively., Conclusions: The RAPIRUN test is useful for the diagnosis of H. pylori infection in the Vietnamese population, showing high specificity, acceptable sensitivity, non-invasiveness, convenience, and rapidity.

The determination of the cagA genotype is generally based on sequencing the variable 3' region of the cagA gene. In a previous study, we successfully generated an anti-East Asian CagA-specific antibody (anti-EAS Ab) immunoreactive only with the East Asian CagA and not with the Western CagA. In a small number of Japanese patients, anti-EAS Ab appeared to be a useful tool for phenotyping CagA immunohistochemically. The present study was conducted to validate the anti-EAS Ab immunohistochemistry method in a larger number of patients from Vietnam and Thailand. A total of 385 Vietnamese and Thais were recruited. Helicobacter pylori status was determined by a combination of three methods, including culture, histology, and immunohistochemistry with anti-H. pylori antibody. The sensitivity, specificity, and accuracy of the anti-EAS Ab immunohistochemistry method for the diagnosis of CagA phenotype were calculated based on the results of the cagA sequencing as the gold standard. The sensitivity, specificity, and accuracy of our immunohistochemistry method were 96.7%, 97.9%, and 97.1%, respectively. Moreover, anti-EAS Ab was not cross-reactive with noninfected gastric mucosa. In conclusion, immunohistochemistry with anti-EAS Ab appears to be a good method for determination of CagA phenotype.

Background: The incidence of gastric cancer differs among countries in Asia, and it has been suggested that virulence factors associated with Helicobacter pylori are partly responsible. The aim of this study was to investigate several genetic factors regarded as virulence or molecular epidemiologic markers in H. pylori isolates from Vietnamese subjects., Results: The cagA, vacA and cag right-end junction genotypes of 103 H. pylori strains from Vietnam (54 from Hanoi and 49 from Ho Chi Minh) were determined by PCR and sequencing. Three types of deletion in the region located upstream of the cagA Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region were identified: the 39-bp deletion type, the 18-bp deletion type, and the no-deletion type. The majority of strains studied (77%; 80/103) had the 18-bp deletion irrespective of geographical location in the country or clinical outcome. All of the 39-bp and 18-bp deletion-type strains possessed the East Asian type cagA repeat region. The type II cag right-end junction genotype was predominant (84%). The vacA m1 genotype was significantly more common in strains isolated in Hanoi, where the incidence of gastric cancer is higher, than in strains from Ho Chi Minh., Conclusion: Pre-EPIYA-region typing of the cagA gene could provide a new genetic marker of H. pylori genomic diversity. Our data support the hypothesis that vacA m1 is closely associated with gastric carcinogenesis.

Interpolation flaps provide an excellent method for reconstruction of large or deep defects where adjacent local tissue cannot supply sufficient donor tissue for repair. These flaps use tissue imported from nonadjacent sites with an inherent blood supply (vascular pedicle) to support the flap while attached to the recipient defect until neovascularization has been ensured between the flap and recipient bed. Hence, they can supply the thickness or bulk needed for large or deep defects and can survive on exposed bone or cartilage. The main disadvantage of these flaps is that they require two stages to complete because the delayed second stage releases the pedicle after inosculation and neovascularization render the tissue independent of the pedicle. This article describes three major interpolation flaps useful in repair of the nose and ear. The forehead, melolabial, and postauricular interpolation flaps are excellent methods that will add to the dermatologic surgeon's reconstructive armamentarium for the repair of large or deep defects.

Therapy for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) does not end with treatment of the initial lesion because almost 50% of patients with one nonmelanoma skin cancer (NMSC) develop another NMSC in the next 5 years. An integrated program of skin cancer awareness, sun protection, and prophylactic approaches is critical. The risk profile of the tumor influences which therapies and specialties will be involved. Most NMSCs may be treated with outpatient methods. Primary care physicians may treat low-risk tumors, but dermatologists specially trained in cutaneous oncology and a multidisciplinary team should manage high-risk lesions. Superficial BCC and SCC may be treated adequately with superficial modalities such as electrodesiccation and curettage (EDC) and cryotherapy. Topical 5-fluorouracil is effective for small in situ lesions. Invasive but low-risk lesions may be treated with EDC and cryotherapy provided that the tumor is limited to the papillary dermis, is not recurrent, and does not have high-risk features. High-risk tumors are best treated with excision and histologic examination or Mohs micrographic surgery (MMS). MMS is the therapeutic gold standard for all NMSCs in terms of cure rates, margin control, and tissue conservation. Because of its higher cost and specialized process, MMS is best reserved for specific indications.

Background: A variety of instruments are available that can objectively assess physical parameters of the skin such as strength, firmness, elasticity, hydration, and color, often undetected by clinical assessment., Objective: To assess the physical properties of healed acute and chronic wounds using several noninvasive instruments., Methods: Four patients with healed acute wounds and four patients with healed chronic wounds were studied using ballistometric, impedance, levarometric, and spectrophotometric measurements., Results: In general, scars were harder, less elastic, dryer, and more erythematous than control skin. These differences were more pronounced in healed chronic wounds., Conclusion: A scar from an acute surgical wound becomes softer, more elastic, dryer, less erythematous, and less pigmented as it ages. In contrast, chronic wound scars become harder as they age. These different properties of healed acute wounds and healed chronic wounds may be a result of the different healing processes in each wound type.