University Transportation Center for Railway Safety
Scholarworks@UTRGV Univ. of Texas RioGrande ValleyNot a member yet
35333 research outputs found
Sort by
Effect of graphene oxide on the upconversion photoluminescence behavior of Er/Yb co-doped PVDF-GO composite nanofibers
No full textUpconversion photoluminescence (UCPL) materials, particularly rare-earth (RE) doped nanoparticles, have garnered significant attention due to their ability to convert near-infrared (NIR) excitation into visible emission, offering benefits such as high photostability, long lifetimes, low autofluorescence, and deep tissue penetration. Among various platforms, polymer-based one-dimensional (1D) nanofibers with in-situ lanthanide doping remain relatively unexplored, despite their superior mechanical flexibility, processability, and potential for improved luminescence performance. In this study, we report the fabrication and UCPL quenching behavior of Er3+/Yb3+ co-doped polyvinylidene difluoride (PVDF) nanofibers incorporated with graphene oxide (GO), synthesized for the first time using the scalable Forcespinning® technique. PVDF, a low-phonon fluorinated polymer, serves as an ideal host to minimize non-radiative losses. GO, a known fluorescence quencher, is introduced to study its effect on the emission intensity and quenching mechanisms of the upconverting fibers. A comprehensive analysis of UCPL intensity variation with GO concentration reveals critical energy transfer interactions between GO and the lanthanide-doped PVDF matrix. This work offers new insights into the design of flexible upconverting platforms and paves the way for their integration in next-generation sensing, biomedical, and optoelectronic applications
Employing AI tools to predict features for dental care use in the United States during the global respiratory illness outbreak
No full textSpinning-Induced Exertional Rhabdomyolysis Without Acute Kidney Injury
No full textRhabdomyolysis is a condition with a myriad of causes, including both traumatic and non-traumatic. Traumatic conditions are observed in crush injuries, compartment syndrome, and fractures, while non-traumatic rhabdomyolysis is commonly seen due to exertional heat stroke, extreme physical exercise, and dehydration. This case report explores two cases of extreme non-traumatic rhabdomyolysis caused by indoor cycling, also known as spinning. A common complication of severe rhabdomyolysis is acute kidney injury (AKI), which increases the risk of renal failure. Rapid interventions such as aggressive intravenous fluids are necessary to prevent kidney function loss. In this case report, two sisters, on two separate occasions, developed Creatine Kinase (CK) levels greater than 100,000 U/L. Recent literature indicates that patients with creatine kinase (CK) levels between 5000 and 10,000 U/L have an increased likelihood of developing acute kidney injury (AKI). However, in these patients, despite creatine kinase (CK) levels ten times greater, these patients demonstrated no signs of acute kidney injury (AKI). This case report aims to highlight the importance of timely treatment of exertional rhabdomyolysis. We also explore the possibility of a genetic predisposition that might increase the likelihood of acquiring this condition. Finally, given the rising cases of spinning-induced rhabdomyolysis, we also highlight preventative measures to prevent future occurrences
Approximate solutions to the one-phase Stefan problem
No full textIn this paper we consider the one-phase Stefan problem for melting and solidification in one-space dimension. By using a modified separation of variables method and power series expansion we obtain approximate solutions to this problem. The constructed solutions satisfy all of the boundary and initial conditions. The properties of the solutions are then studied in the context of the corresponding classical problem and error analysis provided. The advantages and the limitations of the procedure are discussed and numerical examples presented
Is Your Cyst Really a Ganglion Cyst? A Case Report of Angioleiomyoma Mimicking a Plantar Fascia Cystic Lesion
No full textGanglion cysts are among the most common benign soft tissue masses encountered in podiatric clinical practice, and their diagnosis is often presumed based on location, clinical observation, and transillumination. However, this case highlights a diagnostic idiosyncrasy: a lesion clinically presumed to be a ganglion cyst within the plantar fascia was ultimately identified as an angioleiomyoma following surgical excision and histopathological evaluation. This finding underscores the importance of maintaining a broad differential diagnosis when assessing cystic lesions, particularly those that transilluminate, as benign vascular tumors may closely mimic more common entities in both clinical presentation and imaging. More importantly, what if it were not a ganglion cyst? A misdiagnosis could lead to suboptimal treatment plans, including prolonged observation periods, unnecessary immobilization, or repeated aspiration attempts. Such delays in appropriate care emphasize the purpose of this publication, raising awareness of this pathology and its potential to mimic a benign cyst. Our patient lived with this lesion for over 11 years before being properly evaluated and referred to a foot and ankle specialist, with the correct diagnosis of benign angioleiomyoma made only after surgical excision and histopathological analysis. In this article, we discuss the challenges and shortcomings in the diagnostic process and comprehensive management of cystic lesions, the clinical behavior of angioleiomyoma, and the growing advocacy for routine biopsy of all masses and lesions as a standard component of surgical patient care
Low burden of clinically relevant anaemia and thrombocytopenia among adolescents living with HIV receiving tenofovir/lamivudine plus dolutegravir: the CIPHER-ADOLA study in Cameroon
No full textBackground: Anaemia and thrombocytopenia adversely affect adolescent HIV outcomes, yet adolescent-specific data from the tenofovir/lamivudine/dolutegravir (TLD) era remain scarce, and access to full blood count (FBC) testing is limited in Cameroon. We evaluated the prevalence, severity, and factors associated with these cytopenias among adolescents living with HIV (ADLHIV) in the TLD era.
Methods: Multicentre cross-sectional study was conducted among ADLHIV (10-19 years) receiving TLD in the CIPHER-ADOLA cohort in Cameroon. Full blood count, viral load (VL) and CD4-count were performed. Factors associated with anaemia and thrombocytopenia were ascertained.
Results: A total of 252 ADLHIV was enrolled (50.8% male, 83.3% were vertically infected, and 7.2% were underweighted). ART-duration and TLD-exposure were 10 [6-13] years and 26 [12-33] months, respectively. Concerning virological response, 71.4%, 13.1%, and 15.5% had a VL \u3c 50, 50-999, and ≥ 1000, respectively. Overall, 102 (40.5%) were anaemic, with only 2.9% severe. Anaemia rate was twice higher in females (55.6%, p \u3c 0.001); 64.1% with VL ≥ 1000 against 35.0% with VL \u3c 50 (p = 0.003); 60.0% with CD4 \u3c 200 against 35.4% with CD4 \u3e 500 (p = 0.046). Regarding thrombocytopenia, the burden was low (6.7%), but higher among VL ≥ 1000 (p = 0.003). Multivariate analyses showed a threefold higher anaemia prevalence in females (aOR [95% CI: 3.406 [1.8952-5.940]), fivefold without formal education (0.191 [0.047-0.776]), threefold in VL ≥ 1000 copies/ml (0.338 [0.156-0.733]). Thrombocytopenia was fourfold more likely in males (aOR: 0.236 [0.072-0.774]) and sevenfold more likely in individuals with VL ≥ 1000 copies/mL (aOR: 0.140 [0.038-0.510]).
Conclusion: In the TLD era, anaemia remains common but generally mild, and thrombocytopenia is uncommon. Cytopenias were associated with unsuppressed viral load, with a stronger association for anaemia in females. These findings support programmatic targeted haemovigilance prioritising adolescents with unsuppressed viral load, particularly females, in settings where access to FBC testing is limited
Direct ink writing of shear exfoliated two-dimensional nanomaterial- elastomeric multifunctional nanocomposite
No full textDirect ink writing (DIW) of polymer nanocomposites with high loadings of two-dimensional (2D) nanofillers (graphene and hexagonal boron nitride (hBN)) is challenging because of potential clogging, use of hazardous solvents, and agglomeration. Here, in this work, a shear exfoliation and sieving method to prepare DIW ink with high loading of nanofillers produced from low-cost bulk layered materials such as graphite and bulk hBN powder for successful DIW printing without the use of any solvents, binders, or plasticizers. The single-step exfoliation technique resulted in a composite with substantial layer reduction along the c-axis, as confirmed by SEM, TEM, XRD, and Raman analysis. Incorporating exfoliated graphene (40 wt%) increased viscosity by ∼6 orders of magnitude due to enhanced particle–matrix interactions, leading to pronounced yield stress behavior and a yield stress of approximately 1598 Pa, which enabled excellent shape retention during extrusion. Using the DIW technique, porous structures such as desalination membranes, self-sensing bone scaffolds, thermal management coating, and serpentine strain sensors were fabricated. When tested in a direct contact membrane distillation setup, the fabricated membrane demonstrated a promising permeate flux of 21.85 Lm−2h−1 and a salt rejection of 74.3 %. The fabricated serpentine sensor exhibited stable signal variations under cyclic tensile loading, with a working range of 0–200 % strain and a maximum gauge factor of 43,735. A cell culture test using the printed bone scaffold demonstrated promising cell attachment and proliferation. The DIW printed hBN nanocomposite exhibited reversible shape change under heat, demonstrating potential 4D printing capability and efficient thermal management when exposed to high heat or flame
Using low-cost sensors for source attribution and health assessment: An air quality study in Brownsville, Texas
No full textAir quality monitoring remains a challenge in areas lacking or having sparse federal monitoring infrastructure, posing significant barriers to public health research. This study demonstrates the usage of low-cost sensors in addressing gaps in air quality monitoring, source attribution, and health risk assessment in a Brownsville, TX neighborhood impacted by emissions from a barite and celestite mineral processing unit. PM2.5 concentrations were measured using PurpleAir sensors deployed across three residential locations, with the site nearest to the processing unit recording a 24-h averaged PM2.5 concentration of 25.12 μg/m3—approximately 2.79 times higher than the nearest Texas Commission of Environmental Quality (TCEQ) CAMS (Continuous Ambient Monitoring Station) site. Indoor air quality was also evaluated in two of the residential units to characterize the influence of outdoor pollution on indoor microenvironment. The local wind data was used to conduct source attribution, and the results suggested that the mineral processing entity located south of the neighborhood was the likely source of particulate pollution in this middle-income neighborhood. A health risk assessment for PM2.5 exposure was conducted, and the results indicate a hazard quotient level below unity, suggesting low-risk non-carcinogenic effects on the community. This study underscores the pivotal role of low-cost sensors in generating localized air quality data, and their potential to support ameliorative evidence-based interventions
Robust explicit estimators of the shifted Rayleigh distribution under Type II censoring
No full textIn this paper, we consider robust explicit estimators for the shifted Rayleigh distribution under Type II censoring, addressing challenges posed by data contamination. We propose two alternative estimation methods: M-estimation and power-weighted repeated medians (PWRM) as robust alternatives to conventional estimators derived from the maximum likelihood (ML) and ordinary least squares (OLS) approaches. We conduct simulation studies to investigate the efficiency and robustness of these estimators in clean and contaminated data sets. Numerical results show that while all methods perform comparably in the absence of data contamination, the PWRM estimator outperforms OLS and ML in contaminated cases in terms of achieving high relative efficiency and maintaining stability across different levels of censoring considered. Finally, we provide a real-data application for illustrative purposes. Our findings highlight the advantages of robust estimation techniques in improving the accuracy of parameter estimation for the analysis of data with potential data anomalies