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1.
J Chromatogr A ; 1707: 464326, 2023 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-37639846

RESUMO

Preconcentration for on-site detection or subsequent determination is a promising technique for selective sensing explosive markers at low concentrations. Here, we report divinylbenzene monolithic polymer in its blank form (neat-DVB) and as a composite incorporated with sodalite topology zeolite-like metal-organic frameworks (3-ZMOF@DVB), as a sensitive, selective, and cost-effective porous preconcentrator for aliphatic nitroalkanes in the vapor phase as explosive markers at infinite dilution. The developed materials were fabricated as 18 cm gas chromatography (GC) monolithic capillary columns to study their separation performance of nitroalkane mixture and the subsequent physicochemical study of adsorption using the inverse gas chromatography (IGC) technique. A strong preconcentration effect was indicated by a specific retention volume adsorption/desorption ratio equal to 3 for nitromethane on the neat-DVB monolith host-guest interaction, and a 14% higher ratio was observed using the 3-ZMOF@DVB monolithic composite despite the low percentage of 0.7 wt.% of sod-ZMOF added. Furthermore, Incorporating ZMOF resulted in a higher percentage of micropores, increasing the degree of freedom more than bringing stronger adsorption and entropic-driven interaction more than enthalpic. The specific free energy of adsorption (ΔGS) values increased for polar probes and nitroalkanes, denoting that adding ZMOFs earned the DVB monolithic matrix a more specific character. Afterward, Lewis acid-base properties were calculated, estimating the electron acceptor (KA) and electron donor (KB) constants. The neat-DVB was found to have a Lewis basic character with KB/KA = 7.71, and the 3-ZMOF@DVB had a less Lewis basic character with KB/KA = 3.82. An increased electron-accepting nature can be directly related to incorporating sod-ZMOF into the DVB monolithic matrix. This work considers the initial step in presenting a portable explosives detector or preconcentrating explosive markers trace prior to more sophisticated analysis. Additionally, the IGC technique allows for understanding the factors that led to the superior adsorption of nitroalkanes for the developed materials.


Assuntos
Substâncias Explosivas , Estruturas Metalorgânicas , Zeolitas , Polímeros , Alcanos , Bases de Lewis
2.
Cureus ; 15(6): e40531, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37461772

RESUMO

Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterized by an exaggerated response of the immune system (a hypersensitivity response) to the fungus Aspergillus. Aspergillus-associated pericarditis leading to pericardial tamponade is rare. In our case, we presented a case of a 22-year-old female asthmatic patient with no other medical conditions who presented to the emergency department (ED) complaining of severe chest tightness and shortness of breath. Echocardiography revealed significant pleural and pericardial effusion consistent with cardiac tamponade. Both pleural and pericardial fluids were hemorrhagic. Four months later, she presented to the ED with chief complaints of shortness of breath and a cough lasting two days. She was admitted as a case of asthma exacerbation. In the following months, when the patient visited the pulmonology outpatient clinic, the doctors recommended for specific IgE test. Allergen-specific IgE testing was positive for A. fumigatus to confirm the presence of ABPA. As we rolled out other causes of cardiac tamponade, we link the development of cardiac tamponade secondary to an underlying Aspergillus infection. We report this case with the aim of improving clinical knowledge regarding probable causes of cardiac tamponade in patients with asthma, which may facilitate the establishment of early diagnosis and treatment protocols.

3.
J Chromatogr A ; 1694: 463922, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-36931139

RESUMO

Organic monolithic columns are mainly used to separate macromolecules; however, many attempts to extend their performance toward small molecules were examined by incorporating micro- and nanoparticles. The incorporation technique enabled utilizing organic monoliths in gas chromatography (GC) for small molecules, which are still scarce. Here, we prepared a composite matrix of capillary monolithic columns of a zeolite-like metal-organic framework with a sodalite topology (sod-ZMOF) and Divinylbenzene polymer (DVB) for GC separations under 0.5 MPa. Relatively short DVB monolithic columns (18 cm long × 0.25 mm i.d.) incorporated with a tiny amount of sod-ZMOF nanoparticles (0.7 and 1.17 wt%) with an average particle size of 225 nm were successfully fabricated and used to separate linear alkanes and polar probes mixtures with increasing resolution up to 3.7 and 5.1 times, respectively, compared to a blank DVB monolithic column. A high-performance separation of linear alkanes series mixture (methane to decane) was exhibited in less than 2 min. McReynolds constants revealed that sod-ZMOF provided the composite monolith with a nonpolar character yielding a negative average polarity value smaller than the standard squalene column. An Excellent retention time of pentane and octane day-to-day reproducibility was achieved during 16 days and over more than 500 runs with RSD% of 2.25% and 3.3% using a composite monolithic column with 5 mg mL-1 sod-ZMOF (5-ZMOF@DVB). In addition, a qualitative determination of the gas mixture content of three commercially available Lighter gas cartridges was performed via the 5-ZMOF@DVB column. Finally, successfully separating an azeotropic freon mixture of difluoromethane (R-32) and pentafluoroethane (R-125) was achieved with a selectivity of up to 4.84. A further thermodynamic study related the preferential adsorption of R-125 to entropic factors rather than enthalpic while trapping inside ZMOF pores. This work sheds light on utilizing the infinite diversity of MOFs and combining their properties with high permeability and easily fabricated organic monoliths for GC separations of light molecules and gasses. Furthermore, the study highlights the role of GC as an easy and fast approach for the preliminary evaluation of the separation efficiency of porous polymers.


Assuntos
Fluorocarbonos , Estruturas Metalorgânicas , Zeolitas , Polímeros/química , Reprodutibilidade dos Testes , Alcanos/análise , Fluorocarbonos/análise
4.
Cureus ; 15(2): e35285, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36974247

RESUMO

Background Hypoglycemia has a major impact on patient health and glycemic management during insulin therapy for both type 1 (T1DM) and type 2 diabetes mellitus (T2DM). It is the rate-limiting complication in diabetes management that prevents stringent glucose control. Objectives To assess the knowledge and awareness about hypoglycemia as a complication of T2D in adults in Al Qassim, Saudi Arabia. Methods This is a cross-sectional study done among type 2 diabetes patients in Al-Qassim, Kingdom of Saudi Arabia, from January to June 2022. A previously validated online questionnaire was disseminated through social media to gather information from respondents. Participants were chosen via a simple random sampling technique. Data analysis was completed using SPSS (version 23; IBM Corp., Armonk, NY). Results Overall, 213 respondents were included in our study. The majority of them were females (70.9%). The participants' average age was 35.9 + 13.0 years. Our results revealed that the average awareness score of the study population was found to be 3.6 ± 1.1 (by using the Clarke method) and 3.7 ± 2.1 (by using the Gold method). Moreover, we found that impaired awareness of hypoglycemia's prevalence by Clarke's questionnaire was 52.1% and 53.5% by using the Gold questionnaire. In addition, almost half of the respondents reported weakness as a symptom of hypoglycemia over the last six months and unconsciousness over the last 12 months. Hypertension was the most commonly reported chronic disease by our participants. Lastly, factors such as age, gender, educational level, geographic distribution, and history of chronic illness did not show any significant association with impaired awareness of the prevalence of hypoglycemia. Conclusion According to our research, we concluded that patients with type 2 diabetes mellitus in the region of Al-Qassim, Saudi Arabia, had insufficient knowledge about hypoglycemia as a complication of T2D. Moreover, the impaired awareness of hypoglycemia in diabetic patients was found to be high. Hence, there is a need for interventional programs to raise public awareness.

5.
Antibiotics (Basel) ; 9(10)2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-33096893

RESUMO

Bacterial antibiotic resistance has been deemed one of the largest modern threats to human health. One of the root causes of antibiotic resistance is the inability of traditional wastewater management techniques, such as filtration and disinfection, to completely eliminate residual antibiotics from domestic and industrial effluents. In this study, we examine the ability of UiO-66; a metal-organic framework (MOF); in removing the antibiotic Doxycycline from aqueous environments. This study's findings suggest that UiO-66 was able to remove nearly 90% of the initial Doxycycline concentration. To correlate the isothermal data, Langmuir and Freundlich models were used. It was determined that the Langmuir model was best suited. Pseudo-first and -second order models were examined for kinetic data, where the pseudo-second order model was best suited-consistent with the maximum theoretical adsorption capacity found by the Langumir model. Thermodynamic analysis was also examined by studying UiO-66 adsorption under different temperatures. Mechanisms of adsorption were also analyzed through measuring adsorption at varying pH levels, thermogravimetric analysis (TGA), Infrared spectroscopy (IR) and Brunauer-Emmet-Teller (BET). This study also explores the possibility of recycling MOFs through exposure to gamma radiation, heat, and heating under low pressure, in order for UiO-66 to be used in multiple, consecutive cycles of Doxycycline removal.

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