Ru-decorated gallium nitride nanotubes as chemical sensor for detection of purinethol drug: a density functional theory study

We employed density functional B3LYP to inspect the impact of Ru-decoration on a GaN nanotube (GaNNT) sensing performance in detection of purinethol (PT) drug. The interaction of the pristine GaNNT with the PT was found to be weak, and the sensing response is 4.3. Decorating an Ru atom into the GaNNT surface increases the adsorption energy (Ead) of PT from -6.5 to -23.6 kcal/mol. The sensing response significantly rises to 93.6 by Ru-decoration. A short recovery time of 15.7 s is found for the PT desorption from the Ru-decorated GaNNT surface at 298 K. The water solvent reduces Ead of PT to -20.1 kcal/mol. Thus, it suggests that Ru-decorated GaNNT may be a highly sensitive PT sensor with a short recovery time.

Comparison of the Stability of 2H Nanosurfaces by the Adsorption of Small Molecules : A DFT Study

Density functional theory (DFT) calculations were carried out to understand the structural stability of 2D nanosheets of gold and silver in hexagonal phase of 2H by the adsorption of small molecules. In this work, we have obtained the bonding and adsorption properties of such small molecules as H2O, H2O2, and C2H5OH on 2H phase of gold and silver nanosurfaces, through DFT method using Quantum Expresso (QE) code. The high absorption energy values of (-2.45 eV, -2,46 eV, -2, 41 eV) for H2O, H2O2, and C2H5OH molecules on 2H-Au surfaces, respectively obtained than that of 2H-silver surfaces that the interaction between small molecules and both 2H nanosurfaces corresponds to physisorption. However, during the adsorption, the gold surface in the 2H phase (2H-Au) seems to preserve its atomic structure, while 2H-Ag surface changes from 2H to the fcc structure. Based on the analysis of electronic and physicochemical properties, the composite systems of 2H-gold/2H-silver-small molecules exhibit semiconductor behaviour. While 2H-Ag surfaces have short recovery time values for hydrogen peroxide (H2O2), this time is quite long for 2H-Au surfaces. Because of the long recovery time, Au-2H reported surfaces can be a candidate for possible applications of viral capture. Thus, the reported results are significant, and they would stimulate the experimental and further studies.

Improving Gas-Sensing Performance Based on MOS Nanomaterials: A Review

In order to solve issues of air pollution, to monitor human health, and to promote agricultural production, gas sensors have been used widely. Metal oxide semiconductor (MOS) gas sensors have become an important area of research in the field of gas sensing due to their high sensitivity, quick response time, and short recovery time for NO2, CO2, acetone, etc. In our article, we mainly focus on the gas-sensing properties of MOS gas sensors and summarize the methods that are based on the interface effect of MOS materials and micro–nanostructures to improve their performance. These methods include noble metal modification, doping, and core-shell (C-S) nanostructure. Moreover, we also describe the mechanism of these methods to analyze the advantages and disadvantages of energy barrier modulation and electron transfer for gas adsorption. Finally, we put forward a variety of research ideas based on the above methods to improve the gas-sensing properties. Some perspectives for the development of MOS gas sensors are also discussed.

Treatment of chest wall osteoradionecrosis with contralateral breast Y-V flap: case report

Introduction:Chest wall osteoradionecrosis(ORN) in breast cancer is one of the most serious complications of radiation therapy. Treatment requires wide debridement and coverage with a well-vascularized flap. However, the extensive radiation-induced injury, and a limit to performing wide resection of the injured bones are challaged to treatment. Herein, we present our experience with chest wall ORN treated with contralateral breast Y-V flap.Case presentationAn 81-year-old woman diagnosed with ORN of the chest wall had a severe ptotic breast. Reconstruction was planned to cover the open wound of the chest wall using redundant contralateral breast tissue. The flap was elevated in the subfascial plane after an inverted-T incision was made in the lower pole and inframammary fold of the contralateral breast while preserving the perforators of the left lateral thoracic artery. The flap was spread in a Y-V advancement fashion to cover the open wound. The patient was discharged 2 weeks after surgery following suture removal. At 19 months post-operation, there were no complications or recurrences of ulcers. The patient was satisfied with the short recovery time and the surgical results.ConclusionThe contralateral breast Y-V flap allows simple and quick reconstruction, and having more options for chest wall reconstruction will allow for a more flexible treatment plan for each patient.

Theoretical Investigation of Br2 and Cl2 Detection by the Pristine and Co-Doped Graphyne

The Br2 and Cl2 interaction with the intrinsic, and Co-doped graphyne nanosheets has been explored by density functional theory calculations. Two vertical and parallel configurations were identified for Br2 and Cl2 adsorption. Calculations showed that the adsorption of Br2 was stronger than Cl2 on the graphyne nanosheet. Neither Br2 nor Cl2 could make serious changes to the HOMO-LUMO gap (Eg) and electrical resistance pf pristine sheet. By manipulating the structure of pristine graphyne by Co atom, its reactivity and sensitivity dramatically improved toward Br2 and Cl2 gases. Compared to the Cl2, the Br2 much more decreases the electrical resistance and Eg of the Co-doped graphyne (~ -40.25%). Thus, the Co-doped graphyne may selectively recognize the Br2 gas in the presence of Cl2. The computed recovery time value for Br2 from the surface of the Co-doped graphyne is 36.4 s, which shows that the graphyne, as a sensor, benefits from a short recovery time to detect Br2.

Fast response acetone-sensing properties of SnO2 nanoparticles prepared by the sol-gel method

SnO2 nanoparticle architectures were successfully synthesized using a sol-gel method and developed for acetone gas detection. The morphology and structure of the particles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The SnO2 nanoparticle architectures were configured as high-performance sensors to detect acetone and showed a very fast response time (<1 s), a short recovery time (10 s), good repeatability and high selectivity at a relatively low working temperature. Thus, SnO2 nanoparticles should be promising candidates for designing and fabricating acetone gas sensors with good gas sensing performance. The possible gas sensing mechanism is also presented.

Adsorption of the Guanine Molecule Over the Pristine, Nb- and Au-doped Boron Nitride Nanosheets: A DFT Study

A theoretical study has been performed onto the pristine, Nb- and Au-doped boron nitride (BN) nanosheets using DFT calculations with the B3LYP-D3 method in order to evaluate their stabilities and electronic properties. The interaction of the guanine molecule with these clusters was also examined in aim to determine their adsorption properties. The calculations show that the HOMO-LUMO energy gap (Eg) of the BN nanosheet was strongly decreased upon its doping with Nb and Au atoms, implying a strong enhancement in its surface reactivity. The interaction of the guanine with the BN sheet was found to be weak, which leads a slight variation in its energy gap, therefore a low sensitivity of this nanosheet toward the guanine was observed. The guanine adsorption over the NbBN cluster is very strong, and the calculated adsorptions energies are in the range of – 36.7 to – 60.2 kcal mol-1, suggesting a great chemical adsorption. For the AuBN cluster, the guanine molecule has been chemisorbed onto its surface with adsorption energies varying of – 24.2 to – 38.4 kcal mol-1, which are lower than those obtained for the NbBN cluster. Upon adsorption proceess, the energy gap of the NbBN cluster was greatly increased, which leads to a decrease in its electric conductivity, thereby it cannot be a suitable sensor for the guanine molecule. On the contrary, the energy gap of the AuBN cluster was reduced by the effect of the guanine adsorption on its surface, indicating an increase in its electrical conductivity, thus the AuBN cluster possess a great electronic sensitivity to the guanine molecule. Based on the transition state theory, the recovery time of the guanine from the AuBN cluster was estimated of 27.6 s, reflecting that the Au-doped BN nanosheet could be employed as an appropriate nanomaterial for the guanine molecule detection with a short recovery time.

Noble metal (Ag, Au, Pd and Pt) doped TaS2 monolayer for gas sensing: a first-principles investigation

Ag-doped TaS2 monolayers show an obvious change in work function and short recovery time for NO2, which indicates that TaS2-based nanomaterials might be a promising candidate for constructing high-performance NO2 gas sensors.

The use of 3D printing pelvis and hip in a complex THA: clinical experience and reports of literature

Background: Total hip arthroplasty(THA) is a good solution of developmental dysplasia of the hip(DDH). However, patients diagnosed with Crowe type IV are difficult to deal with. With traditional operation skills, the operation time is quite long and the patients will lose a lot of blood.Case presentation: We present the case of a 58-year-old male patient who underwent left THA due to Crowe type IV DDH with the help of 3D printing models. Before the operation, we put the CT image into a computer software named mimics. After getting the stl. document, we use 3D printer to print the models out. By using the models, we planned the operation in advance. And after sterilizing the models, we put them in the operation area, which saves a lot of operation time and reduces much blood loss by giving surgeons a better anatomy view. Conclusion: THA with the help of 3D printing pelvis and femur can result in a relatively short recovery time and provide good clinical efficacy of type IV DDH patients.

The Use of 3D Printing Pelvis and Hip in a Complex THA: Clinical Experience and Reports of Literature

Background: Total hip arthroplasty(THA) is a good solution of developmental dysplasia of the hip(DDH). However, patients diagnosed with Crowe type IV are difficult to deal with. With traditional operation skills, the operation time is quite long and the patients will lose a lot of blood.Case presentation: We present the case of a 58-year-old male patient who underwent left THA due to Crowe type IV DDH with the help of 3D printing models. Before the operation, we put the CT image into a computer software named mimics. After getting the stl. document, we use 3D printer to print the models out. By using the models, wo planned the operation in advance. And after sterilizing the models, we put them in the operation area, which saves a lot of operation time and reduces much blood loss by giving surgeons a better anatomy view. Conclusion: THA with the help of 3D printing pelvis and femur can result in a relatively short recovery time and provide good clinical efficacy of type IV DDH patients.