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1.
Addict Behav ; 155: 108038, 2024 08.
Artigo em Inglês | MEDLINE | ID: mdl-38613857

RESUMO

BACKGROUND: The proposed FDA product standard to prohibit menthol as a characterizing flavor in combustible cigarettes has the potential to significantly reduce tobacco-related health disparities. Whether a menthol e-liquid product standard would improve or hinder public health is unknown. No known research has directly examined the impact of menthol vs. tobacco flavored e-liquid use on acute e-cigarette use patterns, subjective experience, behavioral intentions, and craving and withdrawal among menthol cigarette smokers. METHODS: Black (n = 47) and White (n = 4) nicotine-deprived menthol smokers with limited e-cigarette experience completed two counterbalanced in-laboratory 30-minute ad libitum vaping sessions with menthol and tobacco nicotine salt-based e-liquid in a randomized crossover pilot trial design. Questionnaires assessed reductions in craving and withdrawal and post-session subjective experience and behavioral intentions. Puff topography was measured continuously throughout each vaping session. RESULTS: Measures of puff topography did not differ significantly by e-liquid flavor (all p > .40). Similarly, menthol and tobacco flavored e-cigarettes were both rated positively in terms of subjective effects and behavioral intentions (all p > .10) and about 40 % of participants reported a preference for the tobacco-flavored e-liquid. Finally, participants showed comparable reductions in craving (p = .210) and withdrawal (p = .671) from pre- and post-session regardless of e-liquid flavor. CONCLUSIONS: Among menthol smokers in a lab-based setting, findings suggest that menthol vs tobacco e-liquid flavor has little impact on acute changes in puff patterns, subjective experience, behavioral intentions, or craving and withdrawal.


Assuntos
Negro ou Afro-Americano , Fissura , Estudos Cross-Over , Sistemas Eletrônicos de Liberação de Nicotina , Aromatizantes , Intenção , Mentol , Vaping , População Branca , Humanos , Masculino , Feminino , Vaping/psicologia , Adulto , População Branca/psicologia , Negro ou Afro-Americano/psicologia , Adulto Jovem , Síndrome de Abstinência a Substâncias/psicologia , Projetos Piloto , Pessoa de Meia-Idade , Fumantes/psicologia , Produtos do Tabaco
2.
Int J Biol Macromol ; 258(Pt 1): 128838, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38128798

RESUMO

Pseudomonas aeruginosa is one of the leading causes of opportunistic infections such as chronic wound infection that could lead to multiple organ failure and death. Gallium (Ga3+) ions are known to inhibit P. aeruginosa growth and biofilm formation but require carrier for localized controlled delivery. Lactoferrin (LTf), a two-lobed protein, can deliver Ga3+ at sites of infection. This study aimed to develop a Ga-LTf complex for the treatment of wound infection. The characterisation of the Ga-LTf complex was conducted using differential scanning calorimetry (DSC), Infra-Red (FTIR) and Inductive Coupled Plasma Optical Emission Spectrometry (ICP-OES). The antibacterial activity was assessed by agar disc diffusion, liquid broth and biofilm inhibition assays using the colony forming units (CFUs). The healing capacity and biocompatibility were evaluated using a P.aeruginosa infected wound in a rat model. DSC analyses showed thermal transition consistent with apo-lactoferrin; FTIR confirmed the complexation of gallium to lactoferrin. ICP-OES confirmed the controlled local delivery of Ga3+. Ga-LTf showed a 0.57 log10 CFUs reduction at 24 h compared with untreated control in planktonic liquid broth assay. Ga-LTf showed the highest antibiofilm activity with a 2.24 log10 CFUs reduction at 24 h. Furthermore, Ga-LTf complex is biocompatible without any adverse effect on brain, kidney, liver and spleen of rats tested in this study. Ga-LTf can be potentially promising novel therapeutic agent to treat pathogenic bacterial infections.


Assuntos
Gálio , Ratos , Animais , Gálio/química , Gálio/metabolismo , Gálio/farmacologia , Pseudomonas aeruginosa , Lactoferrina/metabolismo , Antibacterianos/farmacologia , Biofilmes
3.
Artigo em Inglês | MEDLINE | ID: mdl-38038676

RESUMO

TiO2 nanotube arrays grown through electrochemical anodization in a formamide-based electrolyte (TNTA-FA) exhibited a whole host of unusual properties compared to nanotubes grown in the conventional ethylene glycol-based electrolyte (TNTA-EG). TNTA-FA exhibited shorter phonon lifetimes, lower lattice strain, more visible light absorption, lower work function, and a highly unusual adsorbate structure consisting of physisorbed and chemisorbed CO along with linearly adsorbed CO2 and various monodentate and bidentate carbonate species. The observation of adsorbed CO in the dark is highly unusual and indicates spontaneous deoxygenation of CO2 on the surface of TNTA-FA. The significance of this finding is that the formation of CO2•- is no longer the rate-limiting bottleneck for the reduction of CO2 on TNTA-FA surfaces as it is for all TiO2 surfaces. TNTA-FA samples are strongly colored (inclusive of a fluorescent green color) and consist of rounded, vertically oriented hollow cylinders as opposed to the honeycomb-like morphology of TNTA-EG arranged in an approximate triangular lattice. The photocatalytic activity was tested through the CO2 photoreduction and dye degradation tests. Formamide-based nanotubes outperformed the EG-based nanotubes by almost 1.7 and 2 times, respectively, in CO2 reduction and dye degradation tests done on methylene blue, brilliant green, and rhodamine B dyes. These results are attributed to stronger surface band bending in TNTA-FA which facilitates more efficient separation of photogenerated electron-hole pairs.

4.
Eur J Surg Oncol ; 49(10): 107001, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37579618

RESUMO

The laparoscopic approach for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (L-CRS + HIPEC) in highly selected patients was previously reported from the PSOGI registry with a demonstrable reduction in length of stay and post-operative morbidity. This study aims to update this international PSOGI registry with a larger cohort of patients and a longer follow-up period. METHODS: An international registry was designed through a networking database (REDCAP®). All centers performing L-CRS + HIPEC were invited through PSOGI to submit data on their cases. Variables such as demographics, clinical outcomes, and survival were analyzed. RESULTS: A total of 315 L-CRS + HIPEC cases were provided by 14 worldwide centers. A total of 215 patients were included in the L-CRS + HIPEC group. The median peritoneal cancer index (PCI) was 3 (3-5). The median length of stay was 7 days (5-10) and the major morbidity (Clavien-Dindo ≥3) was 6.1% after 30 days. The 5-year disease-free survival (DFS) per tumor origin was: 94% for PMP-LG, 85% for PMP-HG, 100% for benign multicyst peritoneal mesothelioma (MPM), 37.4% for colonic origin, and 54%(at 3 years) for ovarian origin. The 5 years overall survival (OS) per tumor origin was: 100% for PMP-LG, PMP-HG and MPM; 61% for colonic origin, and 74% (at 3 years) for ovarian origin. In addition, a total of 85 patients were analyzed in the laparoscopic risk-reducing HIPEC (L-RR + HIPEC). The median length of stay was 5 days (4-6) and the major morbidity was 6% after 30 days. The 5-year DFS per tumor origin was: 96% for perforated low grade appendiceal mucinous neoplasm (LAMN II) and 68.1% for colon origin. The 5 years OS per tumor origin was: 98% for LAMN II and 83.5% for colonic origin. CONCLUSIONS: Minimally invasive CRS + HIPEC is a safe procedure for selected patients with peritoneal carcinomatosis in specialized centers. It improves perioperative results while providing satisfactory oncologic outcomes. L-RR + HIPEC represents a promising strategy that could be evaluated in patients with high risk of developing peritoneal carcinomatosis into prospective randomized trials.

5.
Nanotechnology ; 34(30)2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37158486

RESUMO

A new type of heavy-metal free single-element nanomaterial, called sulfur quantum dots (SQDs), has gained significant attention due to its advantages over traditional semiconductor QDs for several biomedical and optoelectronic applications. A straightforward and rapid synthesis approach for preparing highly fluorescent SQDs is needed to utilize this nanomaterial for technological applications. Until now, only a few synthesis approaches have been reported; however, these approaches are associated with long reaction times and low quantum yields (QY). Herein, we propose a novel optimized strategy to synthesize SQDs using a mix of probe sonication and heating, which reduces the reaction time usually needed from 125 h to a mere 15 min. The investigation employs cavitation and vibration effects of high energy acoustic waves to break down the bulk sulfur into nano-sized particles in the presence of highly alkaline medium and oleic acid. In contrast to previous reports, the obtained SQDs exhibited excellent aqueous solubility, desirable photostability, and a relatively high photoluminescence QY up to 10.4% without the need of any post-treatment. Additionally, the as-synthesized SQDs show excitation-dependent emission and excellent stability in different pH (2-12) and temperature (20 °C-80 °C) environments. Hence, this strategy opens a new pathway for rapid synthesis of SQDs and may facilitate the use of these materials for biomedical and optoelectronic applications.

6.
Nanomaterials (Basel) ; 13(9)2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37177028

RESUMO

Solar energy harvesting using semiconductor photocatalysis offers an enticing solution to two of the biggest societal challenges, energy scarcity and environmental pollution. After decades of effort, no photocatalyst exists which can simultaneously meet the demand for excellent absorption, high quantum efficiency and photochemical resilience/durability. While CdS is an excellent photocatalyst for hydrogen evolution, pollutant degradation and organic synthesis, photocorrosion of CdS leads to the deactivation of the catalyst. Surface passivation of CdS with 2D graphitic carbon nitrides (CN) such as g-C3N4 and C3N5 has been shown to mitigate the photocorrosion problem but the poor oxidizing power of photogenerated holes in CN limits the utility of this approach for photooxidation reactions. We report the synthesis of exfoliated 2D nanosheets of a modified carbon nitride constituted of tris-s-triazine (C6N7) linked pyromellitic dianhydride polydiimide (CN:PDI) with a deep oxidative highest occupied molecular orbital (HOMO) position, which ensures sufficient oxidizing power for photogenerated holes in CN. The heterojunction formed by the wrapping of mono-/few layered CN:PDI on CdS nanorods (CdS/CN:PDI) was determined to be an excellent photocatalyst for oxidation reactions including photoelectrochemical water splitting, dye decolorization and the photocatalytic conversion of benzyl alcohol to benzaldehyde. Extensive structural characterization using HR-TEM, Raman, XPS, etc., confirmed wrapping of few-layered CN:PDI on CdS nanorods. The increased photoactivity in CdS/CN:PDI catalyst was ascribed to facile electron transfer from CdS to CN:PDI in comparison to CdS/g-C3N4, leading to an increased electron density on the surface of the photocatalyst to drive chemical reactions.

7.
Nanotechnology ; 34(20)2023 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-36787629

RESUMO

Blended films comprising poly(butyl acrylate) (PBA)-grafted cellulose nanocrystals (CNCs) and poly(3-hexylthiophene) (P3HT), exhibited more intense photoluminescence (PL) and longer PL emission lifetimes compared to pristine P3HT films. Optical absorption and photoluminescence spectra indicated reduced torsional disorder i.e. enhanced backbone planarity in the P3HT@CNC blended composites compared to the bare P3HT. Such molecule-level geometrical modification resulted in both smaller interchain and higher intrachain exciton bandwidth in the blended composites compared to the bare P3HT, because of reduced interchain interactions and enhanced intrachain order. These results indicate a potential switch of the aggregation behavior from dominant H-aggregates to J-aggregates, supported by Raman spectroscopy. The reorganization of micromolecular structure and concomitant macroscopic aggregation of the conjugated polymer chains resulted in a longer conjugation length for the P3HT@CNC blended composites compared to the bare P3HT. Additionally, this nanoscale morphological change produced a reduction in the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap of the blends, evidenced from optical absorption spectra. Classical molecular dynamics simulation studies predicted the probability of enhanced planarity in the polymer backbone following interactions with CNC surfaces. Theoretical results from density functional theory calculations corroborate the experimentally observed reduction of optical bandgap in the blends compared to bare P3HT. The blended composite outperformed the bare P3HT in nitro-group PL sensing tests with a pronounced difference in the reaction kinetics. While the PL quenching dynamics for bare P3HT followed Stern-Volmer kinetics, the P3HT@CNC blended composite exhibited a drastic deviation from the same. This work shows the potential of a functionalized rod-like biopolymer in tuning the optoelectronic properties of a technologically important polymeric organic semiconductor through control of the nanoscale morphology.

8.
J Chem Phys ; 158(3): 034901, 2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36681636

RESUMO

In this work, we studied TEMPO-oxidized cellulose nanofibril (OCNF) suspensions in the presence of diverse surfactants. Using a combination of small angle neutron scattering (SANS) and rheology, we compared the physical properties of the suspensions with their structural behavior. Four surfactants were studied, all with the same hydrophobic tail length but different headgroups: hexaethylene glycol mono-n-dodecyl ether (C12EO6, nonionic), sodium dodecyl sulfate (SDS, anionic), cocamidopropyl betaine (CapB, zwitterionic), and dodecyltrimethylammonium bromide (DTAB, cationic). Contrast variation SANS studies using deuterated version of C12EO6 or SDS, or by varying the D2O/H2O ratio of the suspensions (with CapB), allowed focusing only on the structural properties of OCNFs or surfactant micelles. We showed that, in the concentration range studied, for C12EO6, although the nanofibrils are concentrated thanks to an excluded volume effect observed in SANS, the rheological properties of the suspensions are not affected. Addition of SDS or CapB induces gelation for surfactant concentrations superior to the critical micellar concentration (CMC). SANS results show that attractive interactions between OCNFs arise in the presence of these anionic or zwitterionic surfactants, hinting at depletion attraction as the main mechanism of gelation. Finally, addition of small amounts of DTAB (below the CMC) allows formation of a tough gel by adsorbing onto the OCNF surface.


Assuntos
Celulose Oxidada , Tensoativos , Tensoativos/química , Espalhamento a Baixo Ângulo , Dodecilsulfato de Sódio/química
9.
Plant Direct ; 6(12): e469, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36514785

RESUMO

Five genes of large phenotypic effect known to confer abiotic stress tolerance in rice were selected to characterize allelic variation in commercial Colombian tropical japonica upland rice cultivars adapted to drought-prone acid soil environments (cv. Llanura11 and Porvenir12). Allelic variants of the genes ART1, DRO1, SUB1A, PSTOL1, and SPDT were characterized by PCR and/or Sanger sequencing in the two upland cultivars and compared with the Nipponbare and other reference genomes. Two genes were identified as possible targets for gene editing: SUB1A (Submergence 1A), to improve tolerance to flooding, and SPDT (SULTR3;4) (SULTR-like Phosphorus Distribution Transporter), to improve phosphorus utilization efficiency and grain quality. Based on technical and regulatory considerations, SPDT was targeted for editing. The two upland cultivars were shown to carry the SPDT wild-type (nondesirable) allele based on sequencing, RNA expression, and phenotypic evaluations under hydroponic and greenhouse conditions. A gene deletion was designed using the CRISPR/Cas9 system, and specialized reagents were developed for SPDT editing, including vectors targeting the gene and a protoplast transfection transient assay. The desired edits were confirmed in protoplasts and serve as the basis for ongoing plant transformation experiments aiming to improve the P-use efficiency of upland rice grown in acidic soils.

10.
Nutrients ; 14(24)2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36558493

RESUMO

Young children in resource-constrained settings are susceptible to zinc deficiency and its deleterious health effects. The objective of this secondary analysis was to evaluate the effects of the following six interventions on biomarkers of iron and zinc status among a subgroup of young children in Dhaka, Bangladesh, who participated in the Zinc in Powders Trial (ZiPT): (1) standard micronutrient powders (MNPs) containing 4.1 mg zinc and 10 mg iron, daily; (2) high-zinc (10 mg) and low-iron (6 mg) (HiZn LoFe) MNP, daily; (3) HiZn (10 mg) and LoFe (6 mg)/HiZn (10 mg) and no-iron MNPs on alternating days; (4) dispersible zinc tablet (10 mg), daily; (5) dispersible zinc tablet (10 mg), daily for 2 weeks at enrollment and at 12 weeks; (6) placebo powder, daily. At the end of the 24 week intervention period, children in the daily dispersible zinc tablet group exhibited a mean serum zinc concentration (SZC) of 92.5 µg/dL, which was significantly higher than all other groups except the HiZn LoFe MNP alternating group (81.3 µg/dL). MNPs containing 10 mg and 6 mg of iron had a similar impact on biomarkers of iron status, with no evidence of an adverse interaction with zinc.


Assuntos
Anemia Ferropriva , Oligoelementos , Humanos , Criança , Lactente , Pré-Escolar , Zinco , Suplementos Nutricionais , Bangladesh , Micronutrientes , Biomarcadores , Pós , Comprimidos
11.
J Contam Hydrol ; 251: 104068, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36108569

RESUMO

Shallow (<30 m) reducing groundwater commonly contains abundant dissolved arsenic (As) in Bangladesh. We hypothesize that dissolved As in iron (Fe)-rich groundwater discharging to rivers is trapped onto Fe(III)-oxyhydroxides which precipitate in shallow riverbank sediments under the influence of tidal fluctuations. Therefore, the goal of this study is to compare the calculated mass of sediment-bound As that would be sequestered from dissolved groundwater As that discharges through riverbanks of the Meghna River to the observed mass of As trapped within riverbank sediments. To calculate groundwater discharge, a Boussinesq aquifer analytical groundwater flow model was developed and constrained by cyclical seasonal fluctuations in hydraulic heads and river stages observed at three sites along a 13 km reach in central Bangladesh. At all sites, groundwater discharges to the river year-round but most of it passes through an intertidal zone created by ocean tides propagating upstream from the Bay of Bengal in the dry season. The annualized groundwater discharge per unit width at the three sites ranges from 173 to 891 m2/yr (average 540 m2/yr). Assuming that riverbanks have been stable since the Brahmaputra River avulsed far away from this area 200 years ago and dissolved As is completely trapped within riverbank sediments, the mass of accumulated sediment As can be calculated by multiplying groundwater discharge by ambient aquifer As concentrations measured in 1969 wells. Across all sites, the range of calculated sediment As concentrations in the riverbank is 78-849 mg/kg, which is higher than the observed concentrations (17-599 mg/kg). This discovery supports the hypothesis that the dissolved As in groundwater discharge to the river is sufficient to account for the observed buried deposits of As along riverbanks.


Assuntos
Arsênio , Água Subterrânea , Poluentes Químicos da Água , Arsênio/análise , Rios , Sedimentos Geológicos , Compostos Férricos , Poluentes Químicos da Água/análise , Monitoramento Ambiental
12.
Cancer Res ; 82(23): 4444-4456, 2022 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-36169922

RESUMO

Tumor suppressor mutations in head and neck squamous cell carcinoma (HNSCC) dominate the genomic landscape, hindering the development of effective targeted therapies. Truncating and missense mutations in NOTCH1 are frequent in HNSCC, and inhibition of PI3K can selectively target NOTCH1 mutant (NOTCH1MUT) HNSCC cells. In this study, we identify several proteins that are differentially regulated in HNSCC cells after PI3K inhibition based on NOTCH1MUT status. Expression of Aurora kinase B (Aurora B), AKT, and PDK1 following PI3K inhibition was significantly lower in NOTCH1MUT cell lines than in wild-type NOTCH1 (NOTCH1WT) cells or NOTCH1MUT cells with acquired resistance to PI3K inhibition. Combined inhibition of PI3K and Aurora B was synergistic, enhancing apoptosis in vitro and leading to durable tumor regression in vivo. Overexpression of Aurora B in NOTCH1MUT HNSCC cells led to resistance to PI3K inhibition, while Aurora B knockdown increased sensitivity of NOTCH1WT cells. In addition, overexpression of Aurora B in NOTCH1MUT HNSCC cells increased total protein levels of AKT and PDK1. AKT depletion in NOTCH1WT cells and overexpression in NOTCH1MUT cells similarly altered sensitivity to PI3K inhibition, and manipulation of AKT levels affected PDK1 but not Aurora B levels. These data define a novel pathway in which Aurora B upregulates AKT that subsequently increases PDK1 selectively in NOTCH1MUT cells to mediate HNSCC survival in response to PI3K inhibition. These findings may lead to an effective therapeutic approach for HNSCC with NOTCH1MUT while sparing normal cells. SIGNIFICANCE: Aurora B signaling facilitates resistance to PI3K inhibition in head and neck squamous cell carcinoma, suggesting that combined inhibition of PI3K and Aurora kinase is a rational therapeutic strategy to overcome resistance.


Assuntos
Neoplasias de Cabeça e Pescoço , Fosfatidilinositol 3-Quinases , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Fosfatidilinositol 3-Quinases/metabolismo , Aurora Quinase B/genética , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Linhagem Celular Tumoral , Receptor Notch1/metabolismo , Proliferação de Células
13.
Chemosphere ; 308(Pt 2): 136289, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36058378

RESUMO

Elevated dissolved arsenic (As) concentrations in the shallow aquifers of Bangladesh are primarily caused by microbially-mediated reduction of As-bearing iron (Fe) (oxy)hydroxides in organic matter (OM) rich, reducing environments. Along the Meghna River in Bangladesh, interactions between the river and groundwater within the hyporheic zone cause fluctuating redox conditions responsible for the formation of a Fe-rich natural reactive barrier (NRB) capable of sequestering As. To understand the NRB's impact on As mobility, the geochemistry of riverbank sediment (<3 m depth) and the underlying aquifer sediment (up to 37 m depth) was analyzed. A 24-hr sediment-water extraction experiment was performed to simulate interactions of these sediments with oxic river water. The sediment and the sediment-water extracts were analyzed for inorganic and organic chemical parameters. Results revealed no differences between the elemental composition of riverbank and aquifer sediments, which contained 40 ± 12 g/kg of Fe and 7 ± 2 mg/kg of As, respectively. Yet the amounts of inorganic and organic constituents extracted were substantially different between riverbank and aquifer sediments. The water extracted 6.4 ± 16.1 mg/kg of Fe and 0.03 ± 0.02 mg/kg of As from riverbank sediments, compared to 154.0 ± 98.1 mg/kg of Fe and 0.55 ± 0.40 mg/kg of As from aquifer sediments. The riverbank and aquifer sands contained similar amounts of sedimentary organic matter (SOM) (17,705.2 ± 5157.6 mg/kg). However, the water-extractable fraction of SOM varied substantially, i.e., 67.4 ± 72.3 mg/kg in riverbank sands, and 1330.3 ± 226.6 mg/kg in aquifer sands. Detailed characterization showed that the riverbank SOM was protein-like, fresh, low molecular weight, and labile, whereas SOM in aquifer sands was humic-like, older, high molecular weight, and recalcitrant. During the dry season, oxic conditions in the riverbank may promote aerobic metabolisms, limiting As mobility within the NRB.


Assuntos
Arsênio , Água Subterrânea , Poluentes Químicos da Água , Arsênio/análise , Bangladesh , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Água Subterrânea/química , Ferro/análise , Compostos Orgânicos , Rios , Areia , Água , Poluentes Químicos da Água/análise
14.
ACS Appl Mater Interfaces ; 14(21): 24309-24320, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35603941

RESUMO

We report a unique photoanode architecture involving TiO2, g-C3N4, and AuNPs wherein a synergistic enhancement of the photoelectrochemical (PEC) performance was obtained with photocurrent densities as high as 3 mA cm-2 under AM1.5G 1 sun illumination. The PEC performance was highly stable and reproducible, and a photoresponse was obtained down to a photon energy of 2.4 eV, close to the interband damping threshold of Au. The photocurrent enhancement was maximized when the Au plasmon band strongly overlapped the g-C3N4 emission band. Our photoanode architecture, which involved AuNPs buried under TiO2 and a plasmon-induced resonance energy transfer-like interaction between g-C3N4 quantum dots (CNQDs) and AuNPs, solved four major problems associated with plasmonic photoelectrocatalysis─it reduced recombination by limiting eliminating direct electrolyte access to AuNPs, it facilitated electron extraction through single-crystal TiO2 nanorod percolation pathways, it facilitated hole extraction through a defective TiO2 seed layer or canopy, and it expanded the range of visible light harvesting by pumping the Au surface plasmons from CNQDs through exciton-to-plasmon resonant energy transfer.

15.
ACS Appl Mater Interfaces ; 14(21): 24281-24289, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35594152

RESUMO

The deployment of two-dimensional (2D) materials for solar energy conversion requires scalable large-area devices. Here, we present the design, modeling, fabrication, and characterization of monolayer MoS2-based lateral Schottky-junction photovoltaic (PV) devices grown by using chemical vapor deposition (CVD). The device design consists of asymmetric Ti and Pt metal contacts with a work function offset to enable charge separation. These early stage devices show repeatable performance under 1 sun illumination, with VOC of 160 mV, JSC of 0.01 mA/cm2, power conversion efficiency of 0.0005%, and specific power of 1.58 kW/kg. An optoelectronic model for this device is developed and validated with experimental results. This model is used to understand loss mechanisms and project optimized device designs. The model predicts that a 2D PV device with ∼70 kW/kg of specific power can be achieved with minimum optimization to the current devices. By increasing the thickness of the absorber layer, we can achieve even higher performance devices. Finally, a 25 mm2 area solar cell made with a 0.65 nm thick MoS2 monolayer is demonstrated, showing VOC of 210 mV under 1 sun illumination. This is the first demonstration of a large-area PV device made with CVD-grown scalable 2D materials.

16.
iScience ; 25(4): 104142, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35434547

RESUMO

Hyperthermia inhibits DNA double-strand break (DSB) repair that utilizes homologous recombination (HR) pathway by a poorly defined mechanism(s); however, the mechanisms for this inhibition remain unclear. Here we report that hyperthermia decreases H4K16 acetylation (H4K16ac), an epigenetic modification essential for genome stability and transcription. Heat-induced reduction in H4K16ac was detected in humans, Drosophila, and yeast, indicating that this is a highly conserved response. The examination of histone deacetylase recruitment to chromatin after heat-shock identified SIRT1 as the major deacetylase subsequently enriched at gene-rich regions. Heat-induced SIRT1 recruitment was antagonized by chromatin remodeler SMARCAD1 depletion and, like hyperthermia, the depletion of the SMARCAD1 or combination of the two impaired DNA end resection and increased replication stress. Altered repair protein recruitment was associated with heat-shock-induced γ-H2AX chromatin changes and DSB repair processing. These results support a novel mechanism whereby hyperthermia impacts chromatin organization owing to H4K16ac deacetylation, negatively affecting the HR-dependent DSB repair.

17.
Langmuir ; 38(11): 3370-3379, 2022 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-35261240

RESUMO

Electrostatic attractions are essential in any complex formation between the nanofibrils of the opposite charge for a specific application, such as microcapsule production. Here, we used cationized cellulose nanofibril (CCNF)-stabilized Pickering emulsions (PEs) as templates, and the electrostatic interactions were induced by adding oxidized cellulose nanofibrils (OCNFs) at the oil-water interface to form microcapsules (MCs). The oppositely charged cellulose nanofibrils enhanced the solidity of interfaces, allowing the encapsulation of Nile red (NR) in sunflower oil droplets. Microcapsules exhibited a low and controlled release of NR at room temperature. Furthermore, membrane emulsification was employed to scale up the preparation of microcapsules with sunflower oil (SFO) encapsulated by CCNF/OCNF complex networks.


Assuntos
Celulose , Cápsulas , Emulsões , Eletricidade Estática , Óleo de Girassol
18.
Health Sci Rep ; 5(2): e549, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35284647

RESUMO

Background and Aims: Common mental health symptoms (CMHS) like depressive moods, anxiety, and stress are the underlying causes of suicidal behavior. The incidence of suicide is higher among Bangladeshi students. Due to the pandemic, students of health/rehabilitation sciences are at the most significant risk. This study aimed to measure the prevalence rate and predicting factors for depression, anxiety and stress, suicidal ideation, and suicide attempts in Bangladeshi undergraduate rehabilitation students. Methods: This cross-sectional study included data from 731 participants. Descriptive analyses estimated prevalence, and multivariate logistic regression models identified the factors associated with CMHS and suicidal behavior after adjusting the confounders. Results: The result shows a high prevalence of moderate to very severe CMHS and a higher risk of suicidal ideation among rehabilitation students. Sociodemographic factors, illness, behavior, institution, and subject-related issues were identified as the predicting factors of CMHS and suicidal behavior. The students suffering from mental health symptoms reported suicidal ideation and attempted at a significantly higher rate. Conclusion: To deal with CHMS and suicide risk, a holistic, supportive approach from government and academic institutions are essential for minimizing the predicting factors identified by this study. The study is helpful for the government regulatory body and policymakers to take immediate steps for preventing CMHS and suicidal behavior among rehabilitation students in Bangladesh.

19.
Malays Orthop J ; 15(3): 78-83, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34966499

RESUMO

INTRODUCTION: Fractures of the distal femur account for 0.4% of all fractures. They involve about 7% of all femur fractures, with bimodal age distribution, commonly occur during high-velocity trauma of motor vehicle accidents in the younger group of patients and are frequently associated with other skeletal injuries. The treatment of distal femoral fractures has evolved from conservative treatment to more aggressive operative treatment. The aim is to achieve and maintain a good reduction of the joint to allow early active mobilisation, thus minimising the joint stiffness and severe muscular atrophy encountered in the conservative treatment. MATERIALS AND METHODS: This is a retrospective study of 25 patients with distal femur fracture with intra-articular extension treated with open reduction and internal fixation with DFLP, admitted at our institute between 2016 to 2019, with a minimum follow-up of six months. RESULTS: In our study, 19 (76%) patients had excellent to good results. Three (12%) patients had fair outcomes, and three (12%) patients had poor outcomes according to Neer's score. The average time for bone union in closed fractures was earlier (4.25 months) than open fractures, averaging 5.86 months. The outcome was almost similar between closed and open fractures. There were 2 (8%) cases of infection in the early post-operative period, 7 (12%) patients suffered from knee stiffness, and there were 3 (12%) cases with a pre-operative bone loss that required bone grafting. CONCLUSION: Management of complex intra-articular distal femur fracture has always been a challenge. Anatomical reduction of articular fragments and rigid fixation of these fractures are a must. DFLP provides angular stability with multiple options to secure fixation of both metaphyseal and articular fragments with the restoration of the joint congruity, limb length, alignment and rotation, allowing early mobilisation and aggressive physiotherapy without loss of fixation, resulting in gratifying functional outcome and low complication rate.

20.
Nanotechnology ; 33(5)2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34633304

RESUMO

We present the electrical properties of zinc phthalocyanine covalently conjugated to cellulose nanocrystals (CNC@ZnPc). Thin films of CNC@ZnPc sandwiched between two gold electrodes showed pronounced hysteresis in their current-voltage characteristics. The layered metal-organic-metal sandwich devices exhibit distinct high and low conductive states when bias is applied, which can be used to store information. Density functional theory results confirmed wave function overlap between CNC and ZnPc in CNC@ZnPc, and helped visualize the lowest (lowest unoccupied molecular orbital) and highest molecular orbitals (highest occupied molecular orbital) in CNC@ZnPc. These results pave the way forward for all-organic electronic devices based on low cost, earth abundant CNCs and metallophthalocyanines.

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