Anosmia as a prominent symptom of COVID-19 infection.

According to WHO recommendations, everyone must protect themselves against Coronavirus disease 2019 (COVID-19), which will also protect others. Due to the lack of current effective treatment and vaccine for COVID-19, screening, rapid diagnosis and isolation of the patients are essential (1, 2). Therefore, identifying the early symptoms of COVID-19 is of particular importance and is a health system priority. Early studies from COVID-19 outbreak in China have illustrated several non-specific signs and symptoms in infected patients, including fever, dry cough, dyspnea, myalgia, fatigue, lymphopenia, and radiographic evidence of pneumonia (3, 4). Recently, a probability of association between COVID-19 and altered olfactory function has been reported in South Korea, Iran, Italy, France, UK and the United States (5-8). However, to our knowledge, the definite association between COVID-19 and anosmia has not been published.

Improved time to treatment failure with an intermittent oxaliplatin strategy: results of CONcePT.

BACKGROUND: Oxaliplatin is an integral component of colorectal cancer treatment, but its use is limited by neurotoxicity. The Combined Oxaliplatin Neurotoxicity Prevention Trial (CONcePT) tested intermittent oxaliplatin (IO) administration and the use of concurrent calcium and magnesium salts (Ca/Mg), two modifications intended to reduce neurotoxicity and extend the duration of treatment. PATIENTS AND METHODS: In this trial involving double randomization, 140 patients were randomized to receive modified FOLFOX7 plus bevacizumab with IO (eight-cycle blocks of oxaliplatin treatment) versus continuous oxaliplatin (CO); and Ca/Mg versus placebo (pre- and postoxaliplatin infusion). The primary end point was time-to-treatment failure (TTF). RESULTS: One hundred thirty-nine patients were entered and treated up to the point of early study termination due to concerns by the data-monitoring committee (DMC) that Ca/Mg adversely affected tumor response. Tumor response was not a study end point. Given DMC concerns, an additional independent, blinded radiology review of all images showed no adverse effect of treatment schedule or Ca/Mg on response by Response Evaluation Criteria In Solid Tumors. The IO schedule was superior to CO [hazard ratio (HR) = 0.581, P = 0.0026] for both TTF and time-to-tumor progression (TTP) (HR = 0.533, P = 0.047). CONCLUSIONS: An IO dosing schedule had a significant benefit on both TTF and TTP versus CO dosing in this trial despite the very attenuated sample. There was no effect of Ca/Mg on response.

DFT-based finite element analysis of compressive response in armchair phosphorene nanotubes.

In this paper, the finite element method is utilized to evaluate the behavior of the armchair phosphorene nanotubes under the compressive loading. The energy equations of the molecular and structural mechanics are used to obtain the elemental properties. The critical compressive forces of various armchair phosphorene nanotubes are computed with clamped-clamped and clamped-free boundary conditions. Results show that the stability of armchair phosphorene nanotubes increases with increasing nanotube aspect ratio, particularly under clamped-clamped boundary conditions. Finally, the buckling mode shapes of armchair phosphorene nanotubes under different boundary conditions are compared. Our work offers valuable insights into how these nanotubes respond to mechanical stress, helps determine elemental properties, and investigates the effects of nanotube geometry and different boundary conditions on their stability. This knowledge has broad applications in fields like nanotechnology, materials science, and nanomechanics, advancing the understanding of nanoscale materials and their potential for various practical uses.

Analyzing fine scaling quantum effects on the buckling of axially-loaded carbon nanotubes based on the density functional theory and molecular mechanics method.

In this paper, the quantum effects of fine scaling on the buckling behavior of carbon nanotubes (CNTs) under axial loading are investigated. Molecular mechanics and quantum mechanics are respectively utilized to study the buckling behavior and to obtain the molecular mechanics coefficients of fine-scale nanotubes. The results of buckling behavior of CNTs with different chiralities with finite and infinite dimensions are given, and a comparison study is presented on them. The differences between finite and infinite nanotubes reflect the quantum effects of fine scaling on the buckling behavior. In addition, the results show that the dimensional changes highly affect the mechanical properties and the buckling behavior of CNTs to certain dimensions. Moreover, dimensional changes have a significant effect on the critical buckling strain. Beside, in addition to the structure dimensions, the arrangement of structural and boundary atoms have a major influence on the buckling behavior.

Vibrational analysis of double-walled silicon carbide nano-cones: a finite element investigation.

A three-dimensional finite element model is used to investigate the vibrational properties of double-walled silicon carbide nano-cones with various dimensions. The dependence of the vibrational properties of double-walled silicon carbide nano-cones on their length, apex angles and boundary conditions are evaluated. Current model consists a combination of beam and spring elements that simulates the interatomic interactions of bonding and nonbonding. The Lennard-Jones potential is employed to model the interactions between two non-bonding atoms. The fundamental frequency and mode shape of the double-walled silicon carbide nano-cones are calculated.

Updated survival and outcomes for older adults with inoperable stage III non-small-cell lung cancer treated with cisplatin, etoposide, and concurrent chest radiation with or without consolidation docetaxel: analysis of a phase III trial from the Hoosier Oncology Group (HOG) and US Oncology.

BACKGROUND: Concurrent chemoradiation with etoposide and cisplatin (EP/XRT) is standard treatment for inoperable stage III locally advanced non-small-cell lung cancer (LA-NSCLC). Consolidation docetaxel (D; Taxotere) after EP/XRT resulted in increased toxicity but no improvement in survival compared with observation (O). We report updated survival for the entire study population and include an analysis of efficacy and tolerability of EP/XRT with or without D in patients aged ≥ 70 years. PATIENTS AND METHODS: Hoosier Oncology Group LUN 01-24 enrolled 243 patients with LA-NSCLC and randomized 166 after EP/XRT to three cycles of D versus O. the trial was terminated after an analysis of the first 203 patients demonstrated futility of D. RESULTS: Median survival time (MST) for the overall study population was 21.5 months, and 3-, 4-, and 5-year survival rates were 30.7%, 18.0%, and 13.9%, respectively. No differences in MST or 3-year survival were noted between D and O arms. Older patients had similar MST (17.1 versus 22.8 months for younger patients, P = 0.15) but higher rates of grade 3/4 toxicity and hospitalization during induction. CONCLUSIONS: Consolidation docetaxel after EP/XRT does not improve survival in LA-NSCLC. Fit older adults with LA-NSCLC benefit from concurrent chemoradiation similarly as younger patients but experience higher rates of hospitalization and toxicity.

High velocity impact analysis of free-free carbon nanotubes.

In the present work, molecular dynamics (MD) simulations are used to investigate the impact behavior of single-walled carbon nanotubes (SWCNTs) with free boundary conditions in two directions, i.e. vertical and horizontal. To consider the effect of consecutive impacts, the number of carbon nanotubes (CNTs) participated in simulations is chosen from two to five in a row. MD results show that adding the number of impacts increases the magnitude of energy loss in both mentioned directions and reduces the maximum impact force in horizontal cases. In addition, by increasing the velocity of striker CNT from 1 km/s to the maximum value which causes any fracture, the effect of initial velocity on the impact properties and also the ultimate initial velocity for each model are investigated. It is demonstrated that the energy loss and the maximum value of impact force increase as the initial velocity of the striker increases. Also, it is found that the impact strength in the vertical direction is higher than that of the horizontal one, while the horizontal CNTs perform better in the absorption of impact energy. Moreover, for all models, the fracture mechanism of CNTs resulting from the impact process is represented and the procedure of failure is explained.

On the mechanical properties and fracture analysis of polymer nanocomposites reinforced by functionalized silicon carbide nanotubes: A molecular dynamics investigation.

The mechanical characteristics of reinforced polymer nanocomposites with Hydrogen (H)- and Fluorine (F)-functionalized silicon carbide nanotubes (H-and F-fSiCNTs) are investigated herein using molecular dynamics (MD) simulations. The effects of covalent functionalization and chirality of SiCNT, and diverse polymer materials on Young's modulus, maximum stress, and strain to the failure point, as well as strain energy are studied. The results reveal that by increasing the functionalization degree, the maximum stress, maximum strain, elastic modulus, and strain energy decrease. The tensile strength of polymer nanocomposites containing SiCNT is higher than that of pure polymer and polymers containing functionalized silicon carbide nanotubes (fSiCNTs). It is also found that the incorporation of fSiCNT into the polymer matrix (fSiCNT/polymer) gives rise to a considerable improvement in the ultimate strength of nanocomposites compared to the pure polymer. Polymer nanocomposites reinforced by armchair SiCNTs and fSiCNTs withstand higher maximum stresses and possess less longitudinal Young's modulus as compared to the same systems comprising zigzag nanotubes. In every percent of functionalization, the zigzag F-fSiCNT/polymer tends to have a higher Young's modulus as compared to the zigzag H-fSiCNT/polymer. Similarly, the armchair F-fSiCNTs incorporated into the polyethylene (PE) matrix (F-fSiCNTs/PE) are stiffer than the armchair H-fSiCNTs/PE in each weight of functionalization. Moreover, the armchair fSiCNTs/polymer nanocomposites show higher storage of strain energy in comparison with their zigzag counterparts.

Phase III trial of gemcitabine plus docetaxel versus capecitabine plus docetaxel with planned crossover to the alternate single agent in metastatic breast cancer.

BACKGROUND: Safety and efficacy of gemcitabine plus docetaxel (GD) and capecitabine plus docetaxel (CD) were compared in patients with metastatic breast cancer, where the alternate crossover monotherapy (GD→C or CD→G) was predetermined. PATIENTS AND METHODS: Patients were randomly assigned to 3-week cycles of either gemcitabine 1000 mg/m(2) on days 1 and 8 plus docetaxel 75 mg/m(2) on day 1 or capecitabine 1000 mg/m(2) twice daily on days 1-14 plus docetaxel 75 mg/m(2) day 1. Upon progression, patients received crossover monotherapy. Primary end point was time to progression (TtP). Secondary end points evaluated overall response rate (ORR), overall survival (OS), and adverse events (AEs). RESULTS: Despite over-accrual of 475 patients, the trial matured with only 324 of 385 planned TtP events due to patient discontinuations. Human epidermal growth factor receptor 2 status was not captured in this study. More CD patients (28%) discontinued due to AEs than GD patients (18.0%, P = 0.009). TtP [hazard ratio (HR) = 1.101, 95% confidence interval (CI) 0.885-1.370, P = 0.387] and OS (HR = 1.031, 95% CI 0.830-1.280, P = 0.785) were not significantly different comparing GD and CD. ORR was not statistically different (P = 0.239) comparing GD (72 of 207, 34.8%) and CD (78 of 191, 40.8%). TtP, OS, and ORR were not significantly different comparing crossover groups. GD caused greater fatigue, hepatotoxicity, neutropenia, and thrombocytopenia but not febrile neutropenia; CD caused more hand-foot syndrome, gastrointestinal toxicity, and mucositis. CONCLUSIONS: GD and CD produced similar efficacy and toxicity profiles consistent with prior clinical experience.

On the derivation of coefficient of Morse potential function for the silicene: a DFT investigation.

In this paper, the structural and mechanical properties of silicene are investigated by the density functional theory calculations. To calculate Young's, bulk, and shear moduli and Poisson's ratio of the silicene, the optimized unit cells containing two atoms are proposed and the effect of chirality on the elastic properties of silicene is examined. It is shown that the silicene has an isotropic behavior, while graphene has an anisotropic behavior. The results showed that calculated moduli for the silicene are significantly lower than those of graphene in zigzag and armchair directions, while Poisson's ratio of silicene is higher than that of graphene. The paper describes one common type of inharmonic interatomic potentials used for constructing nonlinear models of the material using the modified Morse potential function. Using this concept, the effects of chirality on dissociation energy, inflection point, and coefficients of the modified Morse potential function are studied. Comparison of the cutoff distance value in the modified Morse potential showed that inflection point values for the armchair and zigzag graphene are highly direction-dependent, whereas these values have negligible difference for silicene.

Mechanical properties of group IV single-walled nanotubes: a finite element approach based on the density functional theory.

In this article, the density functional theory is applied to characterize the mechanical properties of single-walled nanotubes of group IV of the periodic table. These materials include carbon nanotube, silicon nanotube, germanium nanotube, and stanene nanotube. (10,10) armchair nanotube is selected for the investigation. By establishing a link between potential energy expressions in molecular and structural mechanics, a finite element approach is proposed for modeling nanotubes. In the proposed model, the nanotubes are considered as an assemblage of beam elements. Young's modulus of the nanotubes is computed by the proposed finite element model. Young's modulus of carbon, silicon, germanium, and tin nanotubes are obtained as 1029, 159.82, 83.23, and 83.15 GPa, respectively, using the density functional theory. Also, the finite element approach gives the values as 1090, 154.67, 85.2, and 82.6 GPa, respectively. It is shown that the finite element model can predict the results of the density functional theory with good accuracy.

Fundamental frequency analysis of endohedrally functionalized carbon nanotubes with metallic nanowires: a molecular dynamics study.

The endohedral functionalization of carbon nanotubes (CNTs) with nanowires (NWs), i.e., NWs@CNTs, has been the center of attention in a lot of research due to the applications of NWs@CNTs in nanoelectronic devices, heterogeneous catalysis, and electromagnetic wave absorption. To this end, based on the classical molecular dynamics (MD) simulations, the effect of four pentagonal structures of encapsulated metallic nanowires (mNWs), namely the eclipsed pentagon (E), the deformed staggered pentagon (Ds), staggered pentagon (S), and staggered pentagonal structure without the monatomic chain passing through the centers of the parallel pentagons (R) configurations on the vibrational behavior of CNTs, is investigated. Also, the effects of geometrical parameters such as length and radius of CNTs on the natural frequencies of simulated models are explored. The results illustrate that by increasing the length, the natural frequency of pure CNTs and mNWs@CNTs decreases. In a similar length, mNWs@CNTs possess lower natural frequencies compared to the pure CNTs. According to the results, the highest and lowest natural frequencies are calculated by inserting the S structure of sodium NW and Ds structure of aluminum NW inside their proper armchair CNT, i.e., Na-S NW@ (9,9) CNT and Al-Ds NW@ (7,7) CNT, respectively.

Torsional buckling analysis of MWCNTs considering quantum effects of fine scaling based on DFT and molecular mechanics method.

In this paper, quantum and molecular mechanics are used to study the quantum effects of fine scaling on the buckling strength of multi-walled carbon nanotubes (MWCNTs), as well as the effects of changes in length, diameter, chirality, wall number and length-to-diameter ratio of the structure under torsional loading. To this end, the total potential energy of the system is calculated with the consideration of both bond stretching and bond angular variations. The density functional theory (DFT) along with the generalized gradient approximation (GGA) function is used to obtain the relevant elastic constants of the nanotubes. The study shows that the quantum effects of fine scaling cause more buckling strength of the structure against external torsional loadings. Also, with any longitudinal change as well as the changes in the structural arrangement that reduce the quantum effects of fine scaling, the strength of the structure decreases sharply.

A randomized, phase III multicenter trial of gemcitabine in combination with carboplatin or paclitaxel versus paclitaxel plus carboplatin in patients with advanced or metastatic non-small-cell lung cancer.

BACKGROUND: Paclitaxel-carboplatin is used as the standard regimen for patients with advanced or metastatic non-small-cell lung cancer (NSCLC). This trial was designed to compare gemcitabine + carboplatin or gemcitabine + paclitaxel to the standard regimen. PATIENTS AND METHODS: A total of 1135 chemonaive patients with stage IIIB or IV NSCLC were randomly allocated to receive gemcitabine 1000 mg/m(2) on days 1 and 8 plus carboplatin area under the concentration-time curve (AUC) 5.5 on day 1 (GC), gemcitabine 1000 mg/m(2) on days 1 and 8 plus paclitaxel 200 mg/m(2) on day 1 (GP), or paclitaxel 225 mg/m(2) plus carboplatin AUC 6.0 on day 1 (PC). Stratification was based on disease stage, baseline weight loss, and presence or absence of brain metastases. Cycles were repeated every 21 days for up to six cycles or disease progression. RESULTS: Median survival (months) with GC was 7.9 compared with 8.5 for GP and 8.7 for PC. Response rates (RRs) were as follows: GC, 25.3%; GP, 32.1%; and PC, 29.8%. The GC arm was associated with a greater incidence of grade 3 or 4 hematologic events but a lower rate of neurotoxicity and alopecia when compared with GP and PC. CONCLUSIONS: Non-platinum and non-paclitaxel gemcitabine-containing doublets demonstrate similar overall survival and RR compared with the standard PC regimen. However, the treatment arms had distinct toxicity profiles.

A DFT-based finite element approach for studying elastic properties, buckling and vibration of the arsenene.

A finite element model is developed to modeli the arsenene nanosheet. To obtain the element properties, which are used to represent As-As bonds in the structure of the arsenene, first principle calculation is used. The developed model is then used to compute Young's modulus, critical compressive force and the fundamental frequency of the arsenene nanosheet with different geometrical parameters. It is seen that the employed finite element model can be efficiently used to predict surface Young's modulus of the arsenene. Furthermore, larger arsenene nanosheets have larger surface Young's modulus. In the next step, the critical compressive forces of the arsenene nanosheet under different boundary conditions are computed. It is seen that the influence of the boundary conditions has higher impact on the bunking force of the smaller arsenenes nanosheets. Finally, investigating the vibrational characteristics of the arsenene nanosheets revealed that increasing the horizontal side length at a constant vertical side length leads to a reduction in the fundamental natural frequency.

A molecular dynamics study on the buckling behavior of single-walled carbon nanotubes filled with gold nanowires.

Molecular dynamics (MD) simulations are carried out to study the buckling of pure gold nanowires (GNWs) and hybrid GNWs@single-walled carbon nanotubes (SWCNTs). The effects of geometrical parameters and endohedral filling of SWCNTs on the critical buckling force are taken into consideration. Two different types of GNWs, namely multi-shell and pentagonal GNWs, with various structures are considered. The results illustrate that the buckling force of the pure GNWs is less than those of the pure SWCNTs and hybrid structures. Also, GNWs possess higher buckling forces by increasing their cross-section area. It is observed that enclosing the GNWs by SWCNTs improves the mechanical behaviors of both CNTs and GNWs. In hybrid multi-shell GNWs@SWCNTs, by increasing the radius, the effect of encapsulation on the buckling force is more remarkable. It can be seen that the encapsulation of pentagonal GNWs has a slightly more effect on the buckling behavior than the encapsulation of multi-shell GNWs. Moreover, it is found out that by increasing the length, the buckling force decreases.

Evaluation of the Morse potential function coefficients for germanene by the first principles approach.

In this paper, first principles calculations are used to investigate atomic structure and mechanical properties of germanene nanosheet. By applying uniaxial and biaxial tensile strains as well as shear strain, the tensile and shear properties of the germanene nanosheet, including Young's and bulk moduli, Poisson's ratio, and shear moduli are computed. Furthermore, the parameters of the modified Morse potential function are calculated for Ge-Ge interaction in the germanene nanosheet. Also, the mechanical behavior of germanene nanosheet is studied under tensile loading at large strains extended to the plastic range. Based on the simulations, Young's modulus of the armchair and zigzag germanene nanosheet are computed as 52.8 and 49.9N/m, respectively. Besides, the values of Poisson's ratio of the armchair and zigzag germanene nanosheet are obtained as 0.35 and 0.29, respectively.

Ameliorating effects of biochar on photosynthetic efficiency and antioxidant defence of Phragmites karka under drought stress.

Biochar (BC) has been reported to improve growth and drought resistance in many plants. However, adequate information on the drought resistance mechanism mediated of BC on Phragmites karka, a bioenergy plant, is not available. The impact of BC addition (0%, 0.75% and 2.5%) on plant growth and physiology of P. karka under drought was assessed. Soil water-holding capacity and soil water content were significantly improved with 0.75% BC as compared with the un-amended controls. This resulted in improved plant performance under drought conditions. An increase of parameters, such as plant fresh and dry biomass, root to shoot ratio and root mass fraction, was paralleled by an increase of chlorophyll content, net photosynthesis rate and water use efficiency of plants. Plants treated with 0.75% BC experienced less oxidative stress due to higher photosystem II efficiency and stimulated activity of antioxidant defense systems. Our results demonstrate that soil amendment with 0.75% BC allow the potential energy plant P. karka to grow in an arid habitat.

Long-term functional restoration by neural progenitor cell transplantation in rat model of cognitive dysfunction: co-transplantation with olfactory ensheathing cells for neurotrophic factor support.

Neural progenitor cell transplantation has emerged as a promising approach for cell replacement therapy in the brain of neurodegenerative diseases. These are multipotent stem cells with self-renewal capabilities and can give rise to cells of all the three lineages of nervous system and can be maintained and differentiated to desirable neuronal subtypes in vitro with known trophic factors. However, like fetal cells, neural progenitor cells after differentiating to specific neuronal type also require continuous neurotrophic factor support for their long-term survival following transplantation. Recent reports suggest that olfactory ensheathing cells are capable of providing continuous neurotrophic factor to the transplanted neural progenitor cells for their long-term survival. In the present investigation, an attempt has been made to validate functional restoration in kainic acid lesioned rat model of cognitive dysfunction following co-transplantation of neural progenitor cells with olfactory ensheathing cells. Animals lesioned with kainic acid in CA3 subfield of hippocampal region were transplanted with neural progenitor cells, olfactory ensheathing cells or neural progenitor cells+olfactory ensheathing cells together. Twelve weeks post-transplantation functional restoration was assessed using neurobehavioral, neurochemical, and immunohistochemical approaches. Significant recovery in learning and memory (89%) was observed in co-transplanted group when compared to lesioned group. This was accompanied by significantly higher expression of choline acetyltransferase and restoration in cholinergic receptor binding in co-transplanted group (61%) over the animals transplanted either olfactory ensheathing cells or neural progenitor cells alone. Role of olfactory ensheathing cells in supplementing neurotrophic factors was further substantiated in vitro by pronounced differentiation of neural progenitor cells to choline acetyltransferase/acetylcholine esterase immunoreactive cells when co-cultured with olfactory ensheathing cells as compared to neural progenitor cells alone. The results strengthened the hypothesis that co-transplantation of olfactory ensheathing cells and neural progenitor cells may be a better approach for functional restoration in kainic acid induced rat model of cognitive dysfunction.

On the mechanical stability and buckling analysis of carbon nanotubes filled with ice nanotubes in the aqueous environment: A molecular dynamics simulation approach.

In this article, molecular dynamics (MD) simulations are utilized to investigate the buckling behavior of carbon nanotubes (CNTs) containing ice nanotubes in the vacuum and aqueous environment. The obtained results show that unlike the critical strain, the critical buckling load of CNT containing ice nanotube is higher than that of pure CNT in the vacuum. It is also indicated that the sensitivity of critical buckling load and the critical strain of CNT containing ice nanotube to the variation of length decreases when the nanostructure is subjected to the aqueous environment. Additionally, it is observed that the calculated critical buckling load and the critical strain of CNTs filled with ice nanotubes in the aqueous environment are respectively larger and smaller than those obtained in the vacuum. It is further observed that CNTs lose their symmetric buckling mode shape as they are filled with ice nanotubes in the vacuum. The results of these simulations can be used as a benchmark for further studies in designing novel potential applications such as proton electronic-based nanoelectromechanical systems (NEMS).