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1.
Sci Rep ; 14(1): 16908, 2024 Jul 23.
Article in English | MEDLINE | ID: mdl-39043685

ABSTRACT

Biofiltration is a method of pollution management that utilizes a bioreactor containing live material to absorb and destroy pollutants biologically. In this paper, we investigate mathematical models of biofiltration for mixing volatile organic compounds (VOCs) for instance hydrophilic (methanol) and hydrophobic ( α -pinene). The system of nonlinear diffusion equations describes the Michaelis-Menten kinetics of the enzymic chemical reaction. These models represent the chemical oxidation in the gas phase and mass transmission within the air-biofilm junction. Furthermore, for the numerical study of the saturation of α -pinene and methanol in the biofilm and gas state, we have developed an efficient supervised machine learning algorithm based on the architecture of Elman neural networks (ENN). Moreover, the Levenberg-Marquardt (LM) optimization paradigm is used to find the parameters/ neurons involved in the ENN architecture. The approximation to a solutions found by the ENN-LM technique for methanol saturation and α -pinene under variations in different physical parameters are allegorized with the numerical results computed by state-of-the-art techniques. The graphical and statistical illustration of indications of performance relative to the terms of absolute errors, mean absolute deviations, computational complexity, and mean square error validates that our results perfectly describe the real-life situation and can further be used for problems arising in chemical engineering.

2.
Small ; : e2401589, 2024 Apr 03.
Article in English | MEDLINE | ID: mdl-38567494

ABSTRACT

Despite possessing substantial benefits of enhanced safety and cost-effectiveness, the aqueous zinc ion batteries (AZIBs) still suffers with the critical challenges induced by inherent instability of Zn metal in aqueous electrolytes. Zn dendrites, surface passivation, and corrosion are some of the key challenges governed by water-driven side reactions in Zn anodes. Herein, a highly reversible Zn anode is demonstrated via interfacial engineering of Zn/electrolyte driven by amino acid D-Phenylalanine (DPA) additions. The preferential adsorption of DPA and the development of compact SEI on the Zn anode suppressed the side reactions, leading to controlled and uniform Zn deposition. As a result, DPA added aqueous electrolyte stabilized Zn anode under severe test environments of 20.0 mA cm-2 and 10.0 mAh cm-2 along with an average plating/stripping Coulombic efficiency of 99.37%. Under multiple testing conditions, the DPA-incorporated electrolyte outperforms the control group electrolyte, revealing the critical additive impact on Zn anode stability. This study advances interfacial engineering through versatile electrolyte additive(s) toward development of stable Zn anode, which may lead to its practical implementation in aqueous rechargeable zinc batteries.

3.
Heliyon ; 10(8): e29491, 2024 Apr 30.
Article in English | MEDLINE | ID: mdl-38681612

ABSTRACT

Background: White pitaya, a popular tropical fruit, is known for its high nutritional value. It is commercially cultivated worldwide for its potential use in the food and pharmaceutical industries. This study aims to assess the nutritional and phytochemical contents and biological potential of the South Chinese White Pitaya (SCWP) peel, flesh, and seed extracts. Methods: Extract fractions with increasing polarity (ethyl acetate < acetone < ethanol < methanol < aqueous) were prepared. Antibacterial potential was tested against multidrug-resistant (MDR) bacteria, and antioxidant activity was determined using, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assays, and cytotoxic activity against human keratinocyte cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Pharmacological screening and molecular docking simulations were conducted to identify potential antibacterial compounds with druggable characteristics. Molecular dynamics simulation (MDS) was employed to validate the binding stability of the promising ligand-protein complexes. Results: All parts of the fruit exhibited a substantial amount of crucial nutrients (minerals, sugars, proteins, vitamins, and fatty acids). The ethanol (ET) and acetone (AC) fractions of all samples demonstrated notable inhibitory effects against tested MDR bacteria, with MIC50 ranges of 74-925 µg/mL. Both ET and AC fractions also displayed remarkable antioxidant activity, with MIC50 ranges of 3-39 µg/mL. Cytotoxicity assays on HaCaT cells revealed no adverse effects from the crude extract fractions. LC-MS/MS analyses identified a diverse array of compounds, known and unknown, with antibacterial and antioxidant activities. Molecular docking simulations and pharmacological property screening highlighted two active compounds, baicalein (BCN) and lenticin (LTN), showing strong binding affinity with selected target proteins and adhering to pharmacological parameters. MDS indicated a stable interaction between the ligands (BCN and LTN) and the receptor proteins over a 100-ns simulation period. Conclusion: Our study provides essential information on the nutritional profile and pharmacological potential of the peel, flesh, and seeds of SCWP. Furthermore, our findings contribute to the identification of novel antioxidants and antibacterial agents that could be capable of overcoming the resistance barrier posed by MDR bacteria.

4.
Sci Rep ; 14(1): 8801, 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38627455

ABSTRACT

This paper presents a study investigating the performance of functionally graded material (FGM) annular fins in heat transfer applications. An annular fin is a circular or annular structure used to improve heat transfer in various systems such as heat exchangers, electronic cooling systems, and power generation equipment. The main objective of this study is to analyze the efficiency of the ring fin in terms of heat transfer and temperature distribution. The fin surfaces are exposed to convection and radiation to dissipate heat. A supervised machine learning method was used to study the heat transfer characteristics and temperature distribution in the annular fin. In particular, a feedback architecture with the BFGS Quasi-Newton training algorithm (trainbfg) was used to analyze the solutions of the mathematical model governing the problem. This approach allows an in-depth study of the performance of fins, taking into account various physical parameters that affect its performance. To ensure the accuracy of the obtained solutions, a comparative analysis was performed using guided machine learning. The results were compared with those obtained by conventional methods such as the homotopy perturbation method, the finite difference method, and the Runge-Kutta method. In addition, a thorough statistical analysis was performed to confirm the reliability of the solutions. The results of this study provide valuable information on the behavior and performance of annular fins made from functionally graded materials. These findings contribute to the design and optimization of heat transfer systems, enabling better heat management and efficient use of available space.

5.
Plant Foods Hum Nutr ; 79(2): 474-481, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38363439

ABSTRACT

Red dragon fruit is gaining popularity globally due to its nutritional value and bioactive components. The study aimed to assess the phytochemical, nutritional composition, antioxidant, antibacterial, and cytotoxic properties of extracts from the South Chinese red dragon fruit peel, flesh, and seeds. Extract fractions with increasing polarity (ethyl acetate

Subject(s)
Anti-Bacterial Agents , Antioxidants , Cactaceae , Fruit , Phytochemicals , Plant Extracts , Fruit/chemistry , Phytochemicals/pharmacology , Phytochemicals/analysis , Antioxidants/pharmacology , Antioxidants/analysis , Humans , Cactaceae/chemistry , Plant Extracts/pharmacology , Plant Extracts/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/analysis , Microbial Sensitivity Tests , Seeds/chemistry , Tandem Mass Spectrometry , HaCaT Cells , Quercetin/analysis , Quercetin/pharmacology , Computer Simulation , Nutritive Value , East Asian People
6.
Dalton Trans ; 53(4): 1809-1816, 2024 Jan 23.
Article in English | MEDLINE | ID: mdl-38173319

ABSTRACT

The development of low-cost earth-abundant electrocatalysts to produce ammonia (NH3) with high efficiency for the nitrogen (N2) reduction reaction (NRR) remains challenging. Herein, we propose the development of highly efficient ultrathin nitrogen-vacancy-rich molybdenum nitride nanosheets (MoN-NV) for NRR using basic electrolytes under ambient conditions. In 0.1 M KOH, this catalyst attained a high faradaic efficiency (FE) of ∼14% with an NH3 yield of 22.5 µg h-1 mg-1cat at -0.3 V vs. a reversible hydrogen electrode under ambient conditions. The characterization results and electrochemical studies disclosed that nitrogen vacancies in the MoN-NV nanosheets played a critical role in the enhanced electrocatalytic activity for NRR. Furthermore, the recycling tests confirmed the stability of the catalyst during NRR electrolysis.

7.
Adv Colloid Interface Sci ; 323: 103068, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38101149

ABSTRACT

The persistent issue of CO2 emissions and their subsequent impact on the Earth's atmosphere can be effectively addressed through the utilization of efficient photocatalysts. Employing a sustainable carbon cycle via photocatalysis presents a promising technology for simultaneously managing the greenhouse effect and the energy dilemma. However, the efficiency of energy conversion encounters limitations due to inadequate carrier utilization and a deficiency of reactive sites. Single-atom catalysts (SACs) have demonstrated exceptional performance in efficiently addressing the aforementioned challenges. This review article commences with an overview of SAC types, structures, fundamentals, synthesis strategies, and characterizations, providing a logical foundation for the design and properties of SACs based on the correlation between their structure and efficiency. Additionally, we delve into the general mechanism and the role of SACs in photocatalytic CO2 reduction. Furthermore, we furnish a comprehensive survey of the latest advancements in SACs concerning their capacity to enhance efficiency, long-term stability, and selectivity in CO2 reduction. Carbon-structured support materials such as covalent organic frameworks (COFs), graphitic carbon nitride (g-C3N4), metal-organic frameworks (MOFs), covalent triazine frameworks (CTFs), and graphene-based photocatalysts have garnered significant attention due to their substantial surface area, superior conductivity, and chemical stability. These carbon-based materials are frequently chosen as support matrices for anchoring single metal atoms, thereby enhancing catalytic activity and selectivity. The motivation behind this review article lies in evaluating recent developments in photocatalytic CO2 reduction employing SACs supported on carbon substrates. In conclusion, we highlight critical issues associated with SACs, potential prospects in photocatalytic CO2 reduction, and existing challenges. This review article is dedicated to providing a comprehensive and organized compilation of recent research findings on carbon support materials for SACs in photocatalytic CO2 reduction, with a specific focus on materials that are environmentally friendly, readily accessible, cost-effective, and exceptionally efficient. This work offers a critical assessment and serves as a systematic reference for the development of SACs supported on MOFs, COFs, g-C3N4, graphene, and CTFs support materials to enhance photocatalytic CO2 conversion.

8.
Case Rep Oncol ; 16(1): 1353-1361, 2023.
Article in English | MEDLINE | ID: mdl-37946745

ABSTRACT

Introduction: Bing-Neel syndrome (BNS) is a rare and heterogenous manifestation of Waldenström macroglobulinemia (WM) involving central nervous system (CNS) infiltration by malignant lymphoplasmacytic cells. Efforts to standardize diagnostic criteria have improved in recent years, as have treatment options including the use of the Bruton tyrosine kinase inhibitor (BTKI) ibrutinib. Case Presentation: Here, we present the case of a 70-year-old male with a remote history of WM previously treated with bendamustine and rituximab, who presented to medical attention with several months of left-sided weakness, headache, and ataxia. Brain magnetic resonance imaging revealed numerous enhancing masses in the bilateral cerebral hemispheres, inferior medulla, and upper cervical spine. Laboratory studies showed serum IgM lambda monoclonal gammopathy and elevated free serum kappa and lambda light chains, while cerebrospinal fluid flow cytometry revealed CD19+ B cells. Stereotactic brain biopsy of a right frontal brain lesion was consistent with lymphoplasmacytic lymphoma, confirmed by a positive MYD88 L265P mutation. He received ibrutinib 420 mg orally daily, and this resulted in appreciable clinical and radiologic responses, which have persisted over a 31-month period. Conclusion: The advent of molecularly targeted agents and novel therapies for WM has provided patients and clinicians with additional therapeutic options. The use of BTK inhibitors with their high-level CNS penetrance, in particular, offers a novel way to treat BNS and improve patient overall survival while maintaining a high level of quality of life. We discuss the importance of MYD88 L265P testing in the context of BNS as well as the expanding role of BTKIs in treating this disease.

9.
Angew Chem Int Ed Engl ; 62(27): e202302174, 2023 Jul 03.
Article in English | MEDLINE | ID: mdl-37010981

ABSTRACT

Rechargeable Zinc batteries (RZBs) are considered a potent competitor for next-generation electrochemical devices, due to their multiple advantages. Nevertheless, traditional aqueous electrolytes may cause serious hazards to long-term battery cycling through fast capacity fading and poor Coulombic efficiency (CE), which happens due to complex reaction kinetics in aqueous systems. Herein, we proposed the novel adoption of the protic amide solvent, N-methyl formamide (NMF) as a Zinc battery electrolyte, which possesses a high dielectric constant and high flash point to promote fast kinetics and battery safety simultaneously. Dendrite-free and granular Zn deposition in Zn-NMF electrolyte assures ultra-long lifespan of 2000 h at 2.0 mA cm-2 /2.0 mAh cm-2 , high CE of 99.57 %, wide electrochemical window (≈3.43 V vs. Zn2+ /Zn), and outstanding durability up to 10.0 mAh cm-2 . This work sheds light on the efficient performance of the protic non-aqueous electrolyte, which will open new opportunities to promote safe and energy-dense RZBs.

10.
Int J Occup Saf Ergon ; 29(2): 912-924, 2023 Jun.
Article in English | MEDLINE | ID: mdl-35678558

ABSTRACT

COVID-19 pandemic has brought unprecedented psychological challenges for frontline healthcare workers, especially nurses, causing anxiety and depression leading to burnout. The responsibility of healthcare leaders has increased manyfold to deal with such challenges. This study attempts to employ the conservation of resources theory to examine the relationship between servant leadership and nurses' burnout, with the mediating role of psychological safety and the moderating effect of trust in leader. A three-wave longitudinal design was employed for data collection from 1204 nurses from 27 hospitals in China. The partial least squares structural equation modeling technique was used for data analyses with SmartPLS version 3.2.8. The findings endorse that servant leadership at time 1 significantly reduces nurses' burnout measured at time 3 through the mediating role of psychological safety measured at time 2, and that a higher level of trust in the leader enhances the impact of servant leadership in reducing nurses' burnout.


Subject(s)
Burnout, Professional , COVID-19 , Humans , Leadership , Trust , Longitudinal Studies , Pandemics , Burnout, Professional/psychology
11.
Struct Multidiscipl Optim ; 65(11): 317, 2022.
Article in English | MEDLINE | ID: mdl-36320454

ABSTRACT

Abstract: The present study analyzes the thermal attribute of conductive, convective, and radiative moving fin with thermal conductivity and constant velocity. The basic Darcy's model is utilized to formulate the governing equation for the problem, which is further nondimensionalized using certain variables. Moreover, an effective soft computing paradigm based on the approximating ability of the feedforword artificial neural networks (FANN's) and meta-heuristic approach of global and local search optimization techniques is developed to quantify the effect of variations in significant parameters such as ambient temperature, radiation-conduction number, Peclet number, nonconstant thermal conductivity, and initial temperature parameter on the temperature gradient of the rod. The results by the proposed FANN-AOA-SQP algorithm are compared with radial basis function approximation, Runge-Kutta-Fehlberg method and machine-learning algorithms. An extensive graphical and statistical analysis based on solution curves and errors such as absolute errors, mean square error, standard deviations in Nash-Sutcliffe efficiency, mean absolute deviations, and Theil's inequality coefficient are performed to show the accuracy, ease of implementation, and robustness of the design scheme.

12.
ACS Omega ; 7(35): 31509-31519, 2022 Sep 06.
Article in English | MEDLINE | ID: mdl-36092561

ABSTRACT

Terpolymerizations of newly synthesized ethylene (E), vinylcyclohexene (VCH), and 1-hexene were carried out with symmetrical metallocene catalysts rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2 (catalyst A) and rac-Et(Ind)2ZrCl2 (catalyst B). X-ray diffractometry (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), high-temperature gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) spectroscopy were used to evaluate the behavior and microstructure of the polymers. The activity of catalyst B was 1.49 × 106 gm/mmolMt·h), with a T m of 73.45 (°C) and ΔH m of 43.19 (J/g), while catalyst A produced first higher 1-hexene, 19.6 mol %, and VCH contents with a narrow molecular weight distribution (MWD). In previous reports, ethylene propylene monomer dienes (EPDM) had a low content and were used for dielectric and insulating properties with nanomaterials. Second, this paper presents a kind of elastomeric polymers based on E/1-hexene and VCH with a high dielectric constant (k = 6-4) and mechanical properties. In addition, low dielectric loss suggests the suitable application potential of these polymeric materials for the fabrications of capacitors. Also, this work reveals that these polymers can be a better candidate for high-voltage electrical insulation due to their enhanced dielectric, mechanical, and thermal characteristics. To examine the insulating property, the interface characteristics of the polymer were evaluated using electrochemical impedance spectroscopy (EIS) with a frequency range of 1 × 105-0.01 Hz and an amplitude of 5.0 mV. EIS is an effective method to investigate the polymers' interfacial electron transfer characteristics. The EIS Nyquist plot showed high Warburg impedance features in the low-frequency domain with straight lines without a semicircle, suggesting that the property of the polymer owing to the high electrical resistance and poor conductivity for ionic kinetics in the electrolyte may have surpassed that of the semicircle. Although the slope of low frequencies in polymers holding potent exoelectrogenic bacteria (Shewanella oneidensis MR-1) as a charge carrier in the electrolyte could significantly reduce the Warburg resistance, it still could not improve the conductivity, which demonstrated that the external charge supply could not alter the insulating property in the used polymers.

13.
Entropy (Basel) ; 24(9)2022 Sep 11.
Article in English | MEDLINE | ID: mdl-36141166

ABSTRACT

The present study concerns the modeling of the thermal behavior of a porous longitudinal fin under fully wetted conditions with linear, quadratic, and exponential thermal conductivities surrounded by environments that are convective, conductive, and radiative. Porous fins are widely used in various engineering and everyday life applications. The Darcy model was used to formulate the governing non-linear singular differential equation for the heat transfer phenomenon in the fin. The universal approximation power of multilayer perceptron artificial neural networks (ANN) was applied to establish a model of approximate solutions for the singular non-linear boundary value problem. The optimization strategy of a sports-inspired meta-heuristic paradigm, the Tiki-Taka algorithm (TTA) with sequential quadratic programming (SQP), was utilized to determine the thermal performance and the effective use of fins for diverse values of physical parameters, such as parameter for the moist porous medium, dimensionless ambient temperature, radiation coefficient, power index, in-homogeneity index, convection coefficient, and dimensionless temperature. The results of the designed ANN-TTA-SQP algorithm were validated by comparison with state-of-the-art techniques, including the whale optimization algorithm (WOA), cuckoo search algorithm (CSA), grey wolf optimization (GWO) algorithm, particle swarm optimization (PSO) algorithm, and machine learning algorithms. The percentage of absolute errors and the mean square error in the solutions of the proposed technique were found to lie between 10-4 to 10-5 and 10-8 to 10-10, respectively. A comprehensive study of graphs, statistics of the solutions, and errors demonstrated that the proposed scheme's results were accurate, stable, and reliable. It was concluded that the pace at which heat is transferred from the surface of the fin to the surrounding environment increases in proportion to the degree to which the wet porosity parameter is increased. At the same time, inverse behavior was observed for increase in the power index. The results obtained may support the structural design of thermally effective cooling methods for various electronic consumer devices.

14.
Polymers (Basel) ; 14(16)2022 Aug 09.
Article in English | MEDLINE | ID: mdl-36015497

ABSTRACT

The objectives of this work were to address the fundamental characteristics of ansa-zirconocene catalyzed E/diene copolymerization and E/diene/1-hexene and E/diene/propylene terpolymerizations, and the quantitative relationship between diene structure and polymer chain propagation rate constant in term of quantifiable catalytic active sites. One of the most important but unknown factors in olefins ansa-zirconocene complexes is the distribution of the catalyst between sites actively participating in polymer chain formation and dormant sites. A set of ethylene/dienes copolymerizations, and ethylene/dienes/1-hexene and ethylene/dienes/1-hexene terpolymerizations catalyzed with ansa-zirconocenes/borate/triisobutylaluminium (rac-Et(Ind)2ZrCl2/[Ph3C][B(C6F5)4]/triisobutylaluminium (TIBA) were performed in toluene at 50 °C To determine the active center [C*]/[Zr] ratio variation in the copolymerization of E with different dienes and their terpolymerization with 1-hexene and propylene, each polymer propagation chain ends were quenched with 2-thiophenecarbonyl, which selectively quenches the metal-polymer bonds through acyl chloride. The ethylene, propylene, 1-hexene, and diene composition-based propagation rate constants (kpE, kpP, kp1-H, and kpdiene), thermal (melting and crystalline) properties, composition (mol% of ethylene, propylene, 1-hexene, and diene), molecular weight, and polydispersity were also studied in this work. Systematic comparisons of the proportion of catalytically [Zr]/[C*] active sites and polymerization rate constant (kp) for ansa-zirconocenes catalyzed E/diene, E/diene/1-hexene, and E/diene/propylene polymerization have not been reported before. We evaluated the addition of 1-hexene and propylene as termonomers in the copolymerization with E/diene. To make a comparison for each diene under identical conditions, we started the polymerization by introducing an 80/20 mole ratio of E/P and 0.12 mol/L of 1-hexene in the system. The catalyst behavior against different dienes, 1-hexene, and propylene is very interesting, including changes in thermal properties, cyclization of 1-hexene, and decreased incorporation of isoprene and butadiene, changes in the diffusion barriers in the system, and its effect on kp.

15.
Nanomaterials (Basel) ; 12(13)2022 Jul 01.
Article in English | MEDLINE | ID: mdl-35808108

ABSTRACT

This paper investigates the heat transfer of two-phase nanofluid flow between horizontal plates in a rotating system with a magnetic field and external forces. The basic continuity and momentum equations are considered to formulate the governing mathematical model of the problem. Furthermore, certain similarity transformations are used to reduce a governing system of non-linear partial differential equations (PDEs) into a non-linear system of ordinary differential equations. Moreover, an efficient stochastic technique based on feed-forward neural networks (FFNNs) with a back-propagated Levenberg-Marquardt (BLM) algorithm is developed to examine the effect of variations in various parameters on velocity, gravitational acceleration, temperature, and concentration profiles of the nanofluid. To validate the accuracy, efficiency, and computational complexity of the FFNN-BLM algorithm, different performance functions are defined based on mean absolute deviations (MAD), error in Nash-Sutcliffe efficiency (ENSE), and Theil's inequality coefficient (TIC). The approximate solutions achieved by the proposed technique are validated by comparing with the least square method (LSM), machine learning algorithms such as NARX-LM, and numerical solutions by the Runge-Kutta-Fehlberg method (RKFM). The results demonstrate that the mean percentage error in our solutions and values of ENSE, TIC, and MAD is almost zero, showing the design algorithm's robustness and correctness.

16.
RSC Adv ; 12(24): 15284-15295, 2022 May 17.
Article in English | MEDLINE | ID: mdl-35693231

ABSTRACT

Copolymerization of ethylene (E) with 5-vinyl-2-norbornene (VNB) catalyzed by ansa-metallocenes allows the precise control of essential polymeric properties such as comonomer incorporation, molecular weight (M w), and polydispersity (D). Significant efforts have been devoted to synthesizing and developing novel catalysts, cocatalysts, and activators, although the fundamental elements of catalytic processes remain unclear. For example, it is questionable how polymeric catalysts are divided across dormant and active sites and how this distribution affects the order of monomers for the propagation rate, which widely vary in the literature. Furthermore, although the empirical correlation between the monomers and average M w has been established in many systems, the fundamental processes of chain termination remain unknown. Furthermore, the involvement of ion-pairing in metallocene-catalyzed polymerization and the termination mechanisms are also contentious issues. In this study, we describe the use of a quenched-labeling technique based on acyl chloride to selectively quench the zirconium metal-polymeric bond, which can be used to study the kinetics, active site [Zr][C*] counting, copolymer microstructure, and molecular weight distribution (MWD) to determine the rate laws for chain initiation, chain propagation rate (R p), propagation rate constant (k p) and chain termination. In addition, we also predict previously unknown chemical characteristics of E/bicyclic copolymerization processes, where either a cis-endocyclic double bond with steric properties or a vinyl exocyclic double bond affects the activity, i.e., [Zr]/[*C], (R p) and (k p). All these properties require the implementation of a particular kinetic mechanism that assumes the low activity of the building copolymer chains incorporating a single ethylene/VNB unit, i.e., the Cp2Zr-C2H5 group, in the ethylene addition process in the Cp2Zr-C bond. Due to ß-agostic stabilization, the Cp2Zr-C2H5 group exhibits a distinct feature. These effects were confirmed experimentally, such as the E/VNB co-polymer activity and VNB mol%, propagation rate decrease in the polymerization time (t p) of 120 s to 1800 s, crystalline properties, and significant increase in molecular weight. The active center [Zr]/[*C] fraction considerably increased in the initial (t p) 840 s, and subsequently tended to the steady stage of 33%, which is lower than previously reported E homo- and E/P copolymerization. The lower [C*]/[Zr] in both the early and stable stages, decrease in VNB mol%, and R p with t p can be associated with the more significant fraction of Cp2Zr-CH2CH3-type dormant site by the ß-agostic hydrogen interaction with the Cp2Zr metal. The t p versus R pE, R pVNB, k pE, k pVNB, and [Zr]/[C*] count could be fitted to a model that invokes deactivation of the growing polymer chains. In the case of the thermal behavior of the copolymers (melting temperature (T m) and crystalline temperature (ΔH m)), T m varied from 101 °C to 121 °C, while ΔH m varied from 9 to 16 (J g-1).

17.
Front Psychol ; 13: 686373, 2022.
Article in English | MEDLINE | ID: mdl-35369243

ABSTRACT

None of the studies published in the extant literature has discussed the role of green innovation climate and green autonomy concerning green creativity and this study aims to offer these two novel constructs. By introducing the componential theory of creativity, this study explores green transformational leadership (GTL), green innovation climate, and green autonomy as antecedents of green creativity. The authors employed structural equation modeling (SEM) to analyze survey-based data collected from automotive firms in China. Data were collected from employee-supervisor working in the automotive industry located in Liaoning province, China. The findings reveal that GTL directly and indirectly via green innovation climate partially mediates the green creativity of employees in China. Moreover, green autonomy moderates the relationship between green innovation climate and green creativity. This pivotal contribution suggests that automotive business enterprises should develop GTL to nurture a green innovation climate and offer green autonomy for the green creativity of employees. The above antecedents of green creativity may enable business firms to gain a competitive advantage by innovating green products and practices.

18.
Clin Nucl Med ; 47(5): 409-413, 2022 May 01.
Article in English | MEDLINE | ID: mdl-35307721

ABSTRACT

BACKGROUND: Peptide receptor radioligand therapy (PRRT) was Food and Drug Administration approved in 2018 for the treatment of unresectable somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors (NETs) and provides an important option for patients with advanced disease. A known adverse effect of this treatment is hematologic toxicity, although usually transient. We present 3 patients with metastatic gastroenteropancreatic NETs treated with PRRT who were evaluated for severe persistent thrombocytopenia. METHODS: Three patients who commenced therapy with PRRT were known to proceed to a bone marrow (BM) biopsy for persistent severe thrombocytopenia and were included in this study. These patients were identified retrospectively and evaluated for their tumor properties, including immunohistochemical markers, treatment modalities, and clinical outcomes. RESULTS: All 3 patients had metastatic NETs that progressed on prior lines of therapy and were treated with 1 to 4 doses of 177Lu-DOTATATE 7.4 GBq (200 mCi) before developing grade 3 (25,000 to 50,000/µL) refractory thrombocytopenia. All patients had concurrent bone metastases, and 2 of the 3 had baseline grade 1 thrombocytopenia. In all 3 cases, BM biopsy documented widespread tumor infiltration. CONCLUSIONS: Severe refractory thrombocytopenia after PRRT is rare and may result from numerous known causes, including radiation-induced myelotoxicity, myelodysplastic syndrome, and tumor BM infiltration. We present 3 cases of thrombocytopenia related to persistent or progressive BM metastasis. Although known bone metastasis is not a contraindication to PRRT, thrombocytopenia may be a manifestation of tumor progression and should be considered when making decisions about continuation of therapy.


Subject(s)
Neuroendocrine Tumors , Organometallic Compounds , Thrombocytopenia , Humans , Neuroendocrine Tumors/complications , Neuroendocrine Tumors/radiotherapy , Octreotide/therapeutic use , Organometallic Compounds/adverse effects , Positron-Emission Tomography , Radionuclide Imaging , Receptors, Peptide , Retrospective Studies , Thrombocytopenia/complications
19.
Polymers (Basel) ; 14(3)2022 Jan 24.
Article in English | MEDLINE | ID: mdl-35160449

ABSTRACT

In toluene at 50 °C, the vinyl addition polymerization of 4-vinyl-cyclohexene (VCH) comonomers with ethylene is investigated using symmetrical metallocene (rac-Et(Ind)2ZrCl2) combined with borate/TIBA. To demonstrate the polymerizations' living character, cyclic VCH with linear-exocyclicπ and endocyclicπ bonds produces monomodal polymers, but the dispersity (Ɖ) was broader. The copolymers obtained can be dissolved in conventional organic solvent and have excellent thermal stability and crystalline temperature (ΔHm), and their melting temperature (Tm) varies from 109 to 126 °C, and ΔHm ranges from 80 to 128 (J/g). Secondly, the distribution of polymeric catalysts engaged in polymer chain synthesis and the nature of the dormant state are two of the most essential yet fundamentally unknown aspects. Comprehensive and exhaustive kinetics of E/VCH have shown numerous different kinetic aspects that are interpreted as manifestations of polymeric catalysts or of the instability of several types of active center [Zr]/[C*] fluctuations and formation rates of chain propagation RpE, RpVCH, and propagation rate constants kpE and kpVCH, the quantitative relationship between RpE, RpVCH and kpE, kpVCH and catalyst structures, their constituent polymer Mw, and their reactivity response to the endocyclic and exocyclic bonds of VCH. The kinetic parameters RpE, RpVCH, kpE, and kpVCH, which are the apparent rates for the metallocene-catalyzed E/VCH, RpE, and kpE values, are much more significant than RpVCH and kpVCH at 120 s, RpE and RpVCH 39.63 and 0.78, and the kpE and kpVCH values are 6461 and 93 L/mol·s, respectively, and minor diffusion barriers are recommended in the early stages. Compared with previously reported PE, RpE and kpE values are 34.2 and 7080 L/mol·s. VCH increases the RpE in the initial stage, as we are expecting; this means that the exocyclic bond of VCH is more active at the initial level, and that the chain transfer reaction of cyclic internal π double is increased with the reaction time. The tp versus Rp, kp, and [Zr]/[C*] fraction count may be fitted to a model that invokes deactivation of growing polymer chains. At tp 120-360 s higher, the incorporation rate of VCH suppresses E insertion, resulting in reduced molecular weight.

20.
Cureus ; 14(1): e21453, 2022 Jan.
Article in English | MEDLINE | ID: mdl-35223237

ABSTRACT

Introduction With recent development in the treatment of trigeminal neuralgia (TN), percutaneous stereotactic rhizotomy is being widely used as an interventional technique. The purpose of this study was to find the recurrence rate of TN in patients who were treated with stereotactic rhizotomy at 80°C for 90 seconds, in a tertiary care set up in a developing country. Methodology A retrospective cohort study was conducted at Shifa International Hospital, Islamabad, Pakistan from September 2016 to August 31, 2021. A total of 57 patients (19 males and 38 females) aged 27-90 years old, whose MRI of the brain had ruled out organic or structural pathologies, and who fulfilled the International Classification of Headache Disorders, 3rd edition for TN were recruited for the study. Of these patients, 51 underwent radiofrequency ablation (RFA) of the trigeminal ganglion (one or more branches of the trigeminal nerve (cranial nerve V (CN V)) in the operation theater. Patients having concomitant comorbid conditions like brain tumors, vascular pathologies, or coagulopathies, those who had previously undergone trigeminal ganglion neurolysis with either alcohol or phenol, who were lost to follow-up before the completion of the six months or had not visited back after the procedure, and those on oral anticoagulants and the ones declared high risk or American Society of Anesthesiologists (ASA) 3 and above for general anesthesia were excluded. Ethical approval was obtained and data were collected from the medical records department. The pain was recorded using the Numeric Rating Scale and recurrence was recorded from the follow-up visits of the patient over at least 12 months. Results Out of 51 patients, three patients who underwent RFA reported recurrence of the same problem for which they had initially reported to the pain clinic and were treated again with RFA. Five patients came back with the neuralgia of a different but contiguous branch of the same Gasserian ganglion opted for the RFA and were treated with no subsequent recurrences. The initial pain relief rate was 84.31%. At the end of the five-year study period, 16 patients reported variable degrees of sensory deficit, and two patients experienced non-debilitating unilateral reversible motor weakness of the jaw. One patient experienced keratitis due to unintentional loss of corneal reflex and subsequent ipsilateral loss of vision. Conclusion RFA is one of the leading treatment options for TN, with lower recurrence at higher temperatures of the radiofrequency electrode, at the cost of more significant sensory and motor deficits.

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