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Mikrochimica Acta Jun 2024The engineering of a home-made portable double-layer filtration and concentration device with the common syringe for rapid analysis of water samples is reported. The...
The engineering of a home-made portable double-layer filtration and concentration device with the common syringe for rapid analysis of water samples is reported. The core elements of the device were two installed filtration membranes with different pore sizes for respective functions. The upper filtration membrane was used for preliminary intercepting large interfering impurities (interception membrane), while the lower filtration membrane was used for collecting multiple target pathogens (enrichment membrane) for determination. This combination can make the contaminated environmental water, exemplified by surface water, filtrated quickly through the device and just retained the target bacteria of Escherichia coli O157:H7, Staphylococcus aureus, and Listeria monocytogenes on the lower enrichment membrane. Integrating with surface-enhanced Raman spectra (SERS) platform to decode the SERS-Tags (SERS-Tag, SERS-Tag, and SERS-Tag) already labeled on each of the enriched bacteria based the antibody-mediated immuno-recognition effect, fast separation, concentration, and detection of multiple pathogenic bacteria from the bulk of contaminated environmental water were realized. Results show that within 30 min, all target bacteria in the lake water can be simultaneously and accurately measured in the range from 10 to 10 CFU mL with detection limit of 10.0 CFU mL without any pre-culture procedures. This work highlights the simplicity, rapidness, cheapness, selectivity, and the robustness of the constructed method for simultaneous detecting multiple pathogens in aqueous samples. This protocol opens a new avenue for facilitating the development of versatile analytical tools for drinking water and food safety monitoring in underdeveloped or developing countries.
Topics: Spectrum Analysis, Raman; Drinking Water; Filtration; Staphylococcus aureus; Listeria monocytogenes; Limit of Detection; Escherichia coli O157; Metal Nanoparticles; Water Microbiology
PubMed: 38942915
DOI: 10.1007/s00604-024-06492-0 -
Nature Communications Jun 2024Transition metal-catalyzed asymmetric hydrogenation is one of the most efficient methods for the preparation of chiral α-substituted propionic acids. However, research...
Transition metal-catalyzed asymmetric hydrogenation is one of the most efficient methods for the preparation of chiral α-substituted propionic acids. However, research on this method, employing cleaner earth-abundant metal catalysts, is still insufficient in both academic and industrial contexts. Herein, we report an efficient nickel-catalyzed asymmetric hydrogenation of α-substituted acrylic acids affording the corresponding chiral α-substituted propionic acids with up to 99.4% ee (enantiomeric excess) and 10,000 S/C (substrate/catalyst). In particular, this method can be used to obtain (R)-dihydroartemisinic acid with 99.8:0.2 dr (diastereomeric ratio) and 5000 S/C, which is an essential intermediate for the preparation of the antimalarial drug Artemisinin. The reaction mechanism has been investigated via experiments and DFT (Density Functional Theory) calculations, which indicate that the protonolysis of the C-Ni bond of the key intermediate via an intramolecular proton transfer from the carboxylic acid group of the substrate, is the rate-determining step.
PubMed: 38942809
DOI: 10.1038/s41467-024-49801-0 -
The Journal of Prosthetic Dentistry Jun 2024While the presence of a ferrule has been reported to be essential for post-and-core restorations, many extensively damaged teeth lack complete ferrules. The outcome of...
STATEMENT OF PROBLEM
While the presence of a ferrule has been reported to be essential for post-and-core restorations, many extensively damaged teeth lack complete ferrules. The outcome of post-and-core restorations for these teeth remains uncertain.
PURPOSE
The purpose of this retrospective clinical study was to assess the outcome of cast alloy post-and-cores and knife-edged crowns for the restoration of teeth lacking complete ferrules.
MATERIAL AND METHODS
A total of 106 participants with endodontically treated teeth with 2 or fewer walls with ferrules who had received cast precious metal alloy post-and-cores along with knife-edged crowns between 2013 and 2022 were recalled for a clinical examination. The minimum follow-up time was 5 months after restoration, and restoration failure and the periodontal status difference between restored teeth and reference teeth were determined. Kaplan-Meier analysis was performed to obtain success curves. The influence of age, sex, jaw position, tooth type, and antagonistic dentition upon the success function was analyzed with the log-rank or Breslow test (α=.05).
RESULTS
A total of 100 participants with 130 restorations were studied. The success rate of the restorations was 93.85% in a mean ±standard deviation period of 48.3 ±26.1 months. The estimated 5-year cumulative success probability was 91.61%. No significant effect on the success of restorations was found regarding age, sex, jaw position, tooth type, or antagonistic dentition (P>.05). The main failure types were post debonding, root fracture, and apical periodontitis. No statistical difference in tooth mobility (Z=-1.265, P=.206) was found between the restored and the reference teeth, but the plaque index and calculus index of the restored teeth were significantly lower than of the reference teeth (Z=-7.216, P<.001; Z=-7.044, P<.001). Teeth that had received cast post-and-cores and knife-edged crowns were found to have no significant correlation with periodontal disease (χ²=1.131, P=.288) or bleeding on probing (χ²=3.436, P=.064).
CONCLUSIONS
The clinical outcomes for the restoration of teeth with 2 or fewer walls with ferrules using cast precious metal alloy post-and-cores and knife-edged crowns were favorable, exhibiting a high 5-year cumulative success probability and no increased periodontal health risk.
PubMed: 38942716
DOI: 10.1016/j.prosdent.2024.05.015 -
Academic Radiology Jun 2024RATIONALE AND OBJECTIVES: Detection of tumor marker location in the breast and axilla using a less commonly utilized color Doppler ultrasound (CDUS) artifact.
UNLABELLED
RATIONALE AND OBJECTIVES: Detection of tumor marker location in the breast and axilla using a less commonly utilized color Doppler ultrasound (CDUS) artifact.
MATERIALS AND METHODS
This prospective study was conducted between August and December 2023 and included consecutive patients with markers placed in the breast and axilla, both before and after neoadjuvant chemotherapy (NACT). Examinations were conducted using a 14 to 5 MHz linear array transducer with B-mode and Doppler capability. By reducing the velocity scale and increasing the color gain values, adjustments were made to create a bloom-like artifact. CDUS was performed with the ultrasound transmit frequency set between 14-5 MHz, color frequency between 6 and 7, color gain ranging from 58 to 80, and velocity scale within the range of 4.6-6.1 cm/s.
RESULTS
Twenty patients, with a mean age of 55.50 years ± 12.04 SD (range, 31-72), were included in the study. 14 (70%) were pre-NACT, and six (30%) were post-NACT patients. A total of 20 breast lesions and six axillary lymph nodes were marked. The breast lesions and axillary lymph nodes where the biopsy marker was placed (14 breast lesions and five axillary lymph nodes before NACT, six breast lesions and one axillary lymph node after NACT) were localized with blooming-like artifact. The average size of breast lesions was 20.95 mm ± 6.56 SD (range, 15-40). For axillary lymph nodes, the average size was 20.63 mm ± 5.01 SD (range: 31-14).
CONCLUSION
The blooming-like CDUS artifact is a novel and easily applicable method determining the location of metallic markers in the breast and axilla on diagnostic examinations.
PubMed: 38942644
DOI: 10.1016/j.acra.2024.05.036 -
Methods in Enzymology 2024Structural biology research of terpene synthases (TSs) has provided a useful basis to understand their catalytic mechanisms in producing diverse terpene products with...
Structural biology research of terpene synthases (TSs) has provided a useful basis to understand their catalytic mechanisms in producing diverse terpene products with polycyclic ring systems and multiple chiral centers. However, compared to the large numbers of>95,000 terpenoids discovered to date, few structures of TSs have been solved and the understanding of their catalytic mechanisms is lagging. We here (i) introduce the basic catalytic logic, the structural architectures, and the metal-binding conserved motifs of TSs; (ii) provide detailed experimental procedures, in gene cloning and plasmid construction, protein purification, crystallization, X-ray diffraction data collection and structural elucidation, for structural biology research of TSs; and (iii) discuss the prospects of structure-based engineering and de novo design of TSs in generating valuable terpene molecules, which cannot be easily achieved by chemical synthesis.
Topics: Alkyl and Aryl Transferases; Crystallography, X-Ray; Terpenes; Cloning, Molecular; Models, Molecular; Protein Conformation
PubMed: 38942516
DOI: 10.1016/bs.mie.2024.03.012 -
Methods in Enzymology 2024Vanadium-dependent haloperoxidases (VHPOs) are a unique family of enzymes that utilize vanadate, an aqueous halide ion, and hydrogen peroxide to produce an electrophilic...
Vanadium-dependent haloperoxidases (VHPOs) are a unique family of enzymes that utilize vanadate, an aqueous halide ion, and hydrogen peroxide to produce an electrophilic halogen species that can be incorporated into electron rich organic substrates. This halogen species can react with terpene substrates and trigger halonium-induced cyclization in a manner reminiscent of class II terpene synthases. While not all VHPOs act in this capacity, several notable examples from algal and actinobacterial species have been characterized to catalyze regio- and enantioselective reactions on terpene and meroterpenoid substrates, resulting in complex halogenated cyclic terpenes through the action of single enzyme. In this article, we describe the expression, purification, and chemical assays of NapH4, a difficult to express characterized VHPO that catalyzes the chloronium-induced cyclization of its meroterpenoid substrate.
Topics: Alkyl and Aryl Transferases; Terpenes; Cyclization; Vanadium; Substrate Specificity; Peroxidases; Enzyme Assays
PubMed: 38942514
DOI: 10.1016/bs.mie.2024.03.024 -
Methods in Enzymology 2024Magnesium ions (Mg) are crucial in class II terpene cyclases that utilize substrates with diphosphate groups. Interestingly, these enzymes catalyze reactions without...
Magnesium ions (Mg) are crucial in class II terpene cyclases that utilize substrates with diphosphate groups. Interestingly, these enzymes catalyze reactions without cleaving the diphosphate group, instead initiating the reaction through protonation. In our recent research, we discovered a novel class II sesquiterpene cyclase in Streptomyces showdoensis. Notably, we determined its crystal structure and identified Mg within its active site. This finding has shed light on the previously elusive question of Mg binding in class II terpene cyclases. In this chapter, we outline our methods for discovering this novel enzyme, including steps for its purification, crystallization, and kinetic analysis.
Topics: Magnesium; Sesquiterpenes; Streptomyces; Binding Sites; Kinetics; Bacterial Proteins; Catalytic Domain; Crystallography, X-Ray; Structure-Activity Relationship; Crystallization; Carbon-Carbon Lyases
PubMed: 38942506
DOI: 10.1016/bs.mie.2024.02.018 -
International Journal of Biological... Jun 2024Passive daytime radiative cooling (PDRC) technology offers a green and sustainable strategy for cooling, eliminating the need for external energy sources through its...
Passive daytime radiative cooling (PDRC) technology offers a green and sustainable strategy for cooling, eliminating the need for external energy sources through its exceptional efficiency in heat radiation and sunlight reflection. Despite its benefits, the widespread usage of non-biodegradable PDRC materials has unfortunately caused environmental pollution and resource wastage. Furthermore, the effectiveness of outdoor PDRC materials can be significantly diminished by rainfall. In this work, a superhydrophobic composite aerogel composed of stereocomplex-type polylactide and ultra-fine glass fiber has been successfully developed through simple physical blending and freeze-drying, which exhibits low thermal conductivity (36.26 mW m K) and superhydrophobicity (water contact angle up to 150°). Additionally, its high solar reflectance (91.68 %) and strong infrared emissivity (93.95 %) enable it to effectively lower surface temperatures during daytime, resulting in a cooling effect of approximately 3.8 °C below the ambient temperature during the midday heat of summer, with a cooling power of 68 W/m. This aerogel offers an environmentally friendly and sustainable approach for the utilization of radiative refrigeration materials, paving the way for environmental protection and sustainable development.
PubMed: 38942401
DOI: 10.1016/j.ijbiomac.2024.133470 -
The American Journal of Medicine Jun 2024African-Americans and Hispanic Americans experience a higher incidence and prevalence of dementia than white Americans while also experiencing more environmental,... (Review)
Review
African-Americans and Hispanic Americans experience a higher incidence and prevalence of dementia than white Americans while also experiencing more environmental, metabolic and nutritional factors potentially promoting such disparities. Greater exposure to air, water and soil pollutants including toxic metals associated with neurodegeneration accrue to both minorities, as does worse dental care than whites exposing them to periodontitis raising dementia risk. Hispanic Americans experience greater occupational exposure to herbicides and pesticides develop more non-alcoholic fatty liver disease (NAFLD) predisposing to dementia. African-Americans have a greater likelihood of both Vitamin D deficiency and magnesium deficiency increasing neuroinflammation and dementia risk. Both have greater air pollution exposure, a known dementia risk. Nutritional changes including greater nut consumption and reduced sugar drink consumption, improved dental care, and reduced toxicant exposure may help reduce this higher risk of dementia among African Americans and Hispanic Americans.
PubMed: 38942346
DOI: 10.1016/j.amjmed.2024.06.023 -
Gastrointestinal Endoscopy Jun 2024
PubMed: 38942326
DOI: 10.1016/j.gie.2024.06.019