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1.
Biomacromolecules ; 25(7): 4581-4590, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38836359

RESUMO

Polylactide is a high potential polymer that can satisfy the growing demand for sustainable and lightweight materials in construction, packaging, and structural applications. However, their high flammability poses a serious concern. Herein, with the aid of solvent exchange and noncovalent interactions, poly(l-lactide) (PLLA) thermoreversible gel was modified with sodium alginate (SA), chitosan (CS), and phytic acid (PA) via a layer-over-layer approach. Freeze-drying of the modified hydrogel furnished a highly flame retardant aerogel with shape stability and no shrinkage. The modified PLLA aerogel (PLLA@SA@CS@PA) exhibited self-extinguishment of flame, the highest limiting oxygen index of any porous polylactide (∼32%), and a tremendous reduction in flammability parameters such as the heat release rate, heat release capacity, total heat release, etc. A comprehensive mechanism of flame retardancy was proposed. This work provides a sustainable strategy for the flame retardant modification of semicrystalline polymer-based aerogels and is expected to expand their practical applications in various industrial sectors.


Assuntos
Alginatos , Quitosana , Retardadores de Chama , Poliésteres , Poliésteres/química , Alginatos/química , Quitosana/química , Géis/química , Eletricidade Estática , Ácido Fítico/química , Porosidade , Hidrogéis/química
2.
Data Brief ; 52: 110061, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38304383

RESUMO

The data was collected from 169 school-going adolescents of grades sixth to twelfth from two cities in South India. The data set contains information of the frequency and type of bullying involvement (perpetration and victimization; physical, verbal, and social) among the participants in traditional and virtual classrooms. The data set can be used by all stakeholders to identify the frequency and types of bullying involvement among Indian adolescents. Further, relevant policies and programs can be developed that is tailored to the Indian adolescent population and the specific sociodemographic groups that are most vulnerable. Researchers can also replicate the study in various parts of India to compare bullying involvement among school-going adolescents across different parts of the nation.

3.
ACS Polym Au ; 4(2): 128-139, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38618004

RESUMO

Strategic customization of crystalline forms of poly(vinylidene fluoride) (PVDF) aerogels is of great importance for a variety of applications, from energy harvesters to thermal and acoustic insulation. Here, we report sustainable strategies to prepare crystalline pure α, ß, and γ forms of PVDF aerogels from their respective gels using a solvent exchange strategy with green solvents, followed by a freeze-drying technique. The crucial aspect of this process was the meticulous choice of appropriate solvents to enable the formation of thermoreversible gels of PVDF by crystallization-induced gelation. Depending on the polymer-solvent interactions, the chain conformation of PVDF can be modulated to obtain gels and aerogels with specific crystalline structures. The crystalline pure α-form and piezoelectric ß-form aerogels were readily obtained by using cyclohexanone and γ-butyrolactone as gelation solvents. On the other hand, the γ-form aerogel was obtained using a binary solvent system consisting of dimethylacetamide and water. These aerogels with distinct crystalline structures exhibit different morphologies, mechanical properties, hydrophobicities, acoustic properties, and electrical properties. Measurement of thermal conductivity for these aerogels showed exceptionally low thermal conductivity values of ∼0.040 ± 0.003 W m-1 K-1 irrespective of their crystal structures. Our results showcase the fabrication approaches that enable PVDF aerogels with varied physicochemical properties for multifunctional applications.

4.
Bioengineering (Basel) ; 11(5)2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38790314

RESUMO

Excessive fibrosis and resultant poor control of intraocular pressure (IOP) reduce the efficacy of glaucoma surgeries. Historically, corticosteroids and anti-fibrotic agents, such as mitomycin C (MMC) and 5-fluorouracil (5-FU), have been used to mitigate post-surgical fibrosis, but these have unpredictable outcomes. Therefore, there is a need to develop novel treatments which provide increased effectiveness and specificity. This review aims to provide insight into the pathophysiology behind wound healing in glaucoma surgery, as well as the current and promising future wound healing agents that are less toxic and may provide better IOP control.

5.
Cureus ; 16(9): e68670, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39371887

RESUMO

We describe a 29-year-old Iranian male with Jalili-Smith syndrome (JSS), who presented with acute angle closure glaucoma. JSS is a rare autosomal recessive oculo-dental disorder characterized by cone-rod dystrophy and amelogenesis imperfecta. Though the disease is observed worldwide, many cases are concentrated in the Gaza Strip. Consanguinity is an important risk factor. Patients typically present with photophobia, nystagmus, and enamel deformation. Our patient exhibited nystagmus, photophobia, cataracts, hyperopia, narrow-angle glaucoma, marked thinning of the retina, and bull's eye maculopathy. In addition, we describe the findings of optical coherence tomography angiography (OCTA). Our patient also underwent phacoemulsification in both eyes with concomitant minimally invasive glaucoma surgeries (MIGS). To the best of our knowledge, narrow-angle glaucoma, OCTA findings, and cataract surgery combined with MIGS have not been reported before in patients with JSS.

6.
Cureus ; 16(3): e56569, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38646330

RESUMO

INTRODUCTION: The underrepresentation of underrepresented minorities (URMs) in the medical field, particularly in ophthalmology, poses a critical challenge to achieving diversity and equity. While URMs constitute 19% of medical school attendees, their presence is markedly lower in ophthalmology residency programs and among practicing ophthalmologists. This study seeks to investigate the prevalence of diversity statements on ophthalmology residency program websites and their role in the underrepresentation of URMs within the field. METHODS: This observational, cross-sectional study analyzed the websites of 126 ophthalmology residency programs listed on the San Francisco (SF) Match website. Diversity statements were categorized based on their inclusion of specific underrepresented groups (race or ethnicity, gender, sexual orientation, and disability) and analyzed for correlation with program characteristics. Descriptive statistics and Chi-squared tests were utilized to assess the prevalence of diversity statements and their association with program size, ranking, geographical location, and institutional nature. RESULTS: Of the 126 programs analyzed, 21 (16.7%) had diversity statements specific to the ophthalmology residency program, and 115 (91.3%) featured institutional-level diversity statements. Race or ethnicity was the most commonly addressed category in diversity statements (75.3%), followed by gender (65.9%), sexual orientation (61.1%), and disability (53.2%). Statistical analyses revealed no significant correlation between program size and the presence of diversity statements. However, higher-ranked programs were more likely to mention sexual orientation and disability. Significant differences were observed at the institutional level, with public institutions more likely to include specific diversity categories. CONCLUSION: The study highlights a significant disparity in the presence and focus of diversity statements across ophthalmology residency programs. Despite a high prevalence of institutional-level diversity statements, program-specific initiatives are lacking, particularly in addressing disability inclusion. The findings suggest a need for a more comprehensive and targeted effort to address underrepresentation in ophthalmology.

7.
ACS Appl Mater Interfaces ; 15(42): 49567-49582, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37842998

RESUMO

Polymer hybrid materials that contain reinforcements with a preferred orientation have received growing attention because of their unique properties and promising applications in multifunctional fields. Herein, anisotropic poly(vinylidene fluoride) (PVDF)/MXene hybrid aerogels with highly ordered delaminated MXene nanosheets and anisotropic porous structures were successfully fabricated by unidirectional freezing of thermoreversible gels followed by a freeze-drying process. The strong interfacial interactions between PVDF chains and abundant functional groups on the surface of MXene enabled the orientation of MXene nanosheets at the boundaries of ice crystals as the semicrystalline PVDF and delaminated MXene nanosheets are squeezed along the freezing direction. These aerogels display distinct properties along the freezing and perpendicular to the freezing (transverse) directions. These anisotropic aerogels are flexible and flame-retardant and possess an anisotropic compression performance, heat transfer, electrical conductivity, and electromagnetic interference (EMI) shielding. Further, by increasing the MXene loadings, the electrical conductivity and EMI shielding performances of hybrid aerogels were significantly improved. The PVDF aerogel showed sticky hydrophobicity with a contact angle of 139°, whereas the contact angle increased significantly in hybrid aerogels (153°) with low water adhesion, making them suitable as self-cleaning materials. The combination of the above characteristics makes these hybrid aerogels potential candidates for a wide range of electronic applications.

8.
Adv Ophthalmol Pract Res ; 3(3): 119-125, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37846359

RESUMO

Purpose: To quantitatively measure and compare the vascular morphology in healthy eyes and eyes with primary open-angle glaucoma (POAG) using optical coherence tomography angiography (OCTA) scans. Methods: This is a retrospective and cross-sectional study which include healthy individuals and individuals with POAG that underwent OCTA imaging at an academic center's glaucoma clinic. We analyzed OCTA scans of the macula and optic nerve head (ONH) of one eye from each subject to quantitatively measure vessel density (VD), vessel length density (VLD), and branchpoint density (BPD). We compared these 3 parameters between the healthy and POAG groups and used logistic regression classification models to determine their diagnostic value in differentiating healthy and glaucomatous eyes. Results: We included 49 healthy subjects and 49 subjects with POAG. After age-adjusted analysis, the parameters of VD, VLD, and BPD were significantly reduced in eyes with POAG (P â€‹< â€‹0.001) in all scan layers and most significantly around the ONH. The parameter with the best performances were radial peripapillary capillary (RPC) VD [AUC (areas under the curve): 0.939 (0.891, 0.987)] which had statistically higher performances (P â€‹< â€‹0.05) than parameters in the superficial or deep layers. All 3 parameters in the RPC layer had statistically similar performances. Conclusions: We found that VD, VLD, and BPD were reduced in glaucomatous eyes. The morphologic parameters of VLD and BPD had similar performances to the traditional parameter of VD in RPC layers. Our results suggest that vascular morphology parameters may provide additional value in the diagnosis and evaluation of glaucoma.

9.
ACS Macro Lett ; 11(11): 1272-1277, 2022 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-36282095

RESUMO

Polymer-based multicolor emissive materials have growing demand due to their potential applications in various fields such as full-color displays, bioimaging, and light sources because of their processability and high stability. Herein, we report dual-color emissive hybrid materials based on biocompatible poly(l-lactide) and polyethylene glycol-modified two-dimensional layered double hydroxide quantum dots (PEG-LDHQDs). The morphology of polymer films tunes the spatial distribution of QDs within the polymer matrix, modulating the energy transfer between the QDs and affording the dual emission behavior in the aggregated states. The amorphous hybrid films show single emission (blue) from the finely dispersed QDs (mostly isolated) within the polymer matrix. In contrast, dual emission (blue and red) was observed when the polymer was crystallized due to the possible accumulation of QDs at the interface of crystalline and amorphous phases in the lamellar structure. Furthermore, the dual emission could be enhanced by the aggregation of QDs on the pores of the breath figure pattern constructed on the surface of the hybrid film.


Assuntos
Pontos Quânticos , Transferência de Energia , Polímeros/química , Pontos Quânticos/química
10.
Bioengineered ; 13(5): 14028-14046, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35730402

RESUMO

Bioethanol industries and bioprocesses have many challenges that constantly impede commercialization of the end product. One of the bottlenecks in the bioethanol industry is the challenge of discovering highly efficient catalysts that can improve biomass conversion. The current promising bioethanol conversion catalysts are microorganism-based cellulolytic enzymes, but lack optimization for high bioethanol conversion, due to biological and other factors. A better understanding of molecular underpinnings of cellulolytic enzyme mechanisms and significant ways to improve them can accelerate the bioethanol commercial production process. In order to do this, experimental methods are the primary choice to evaluate and characterize cellulase's properties, but they are time-consuming and expensive. A time-saving, complementary approach involves computational methods that evaluate the same properties and improves our atomistic-level understanding of enzymatic mechanism of action. Theoretical methods in many cases have proposed research routes for subsequent experimental testing and validation, reducing the overall research cost. Having a plethora of tools to evaluate cellulases and the yield of the enzymatic process will aid in planning more optimized experimental setups. Thus, there is a need to connect the computational evaluation methods with the experimental methods to overcome the bottlenecks in the bioethanol industry. This review discusses various experimental and computational methods and their use in evaluating the multiple properties of cellulases.


Assuntos
Celulases , Biocombustíveis , Biomassa , Celulose , Hidrólise
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