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The design and simulation of meshing of a single enveloping worm-gear drive with a localized bearing contact is considered. The bearing contact has a longitudinal direction and two branches of contact path. The purpose of localization is to reduce the sensitivity of the worm-gear drive to misalignment. The author's approach for localization of bearing contact is based on the proper mismatch of the surfaces of the hob and drive worm. The developed computer program allows the investigation of the influence of misalignment on the shift of the bearing contact and the determination of the transmission errors and the contact ratio. The developed approach has been applied for K type of single-enveloping worm-gear drives and the developed theory is illustrated with a numerical example. [S1050-0472(00)00502-X]

Background: Currently, there is no clearly established therapy to treat mild cognitive impairment (MCI); consequently, alternative therapies, such as acupuncture, have been attempted. In many clinical studies, the potential benefits of acupuncture for cognitive improvement have been identified in clinical outcomes; however, the mechanism remains unclear. Accordingly, this study aims to investigate the therapeutic mechanism of acupuncture therapy using functional near-infrared spectroscopy and its feasibility in treating individuals with impaired cognitive function. Methods: This study is designed to be a prospective, two-arm, parallel clinical trial involving 24 participants. The patient group will be treated with acupuncture twice per week for 12 weeks; meanwhile, the healthy control group will not undergo acupuncture treatment. Functional near-infrared spectroscopy assessment and a working memory test will be performed at baseline and every 6 weeks to investigate the therapeutic mechanism of acupuncture. The primary outcome will be measured using the Korean version of the Montreal Cognitive Assessment. The secondary outcomes will be the Alzheimer's Disease Assessment Scale-cognitive subscale score, working memory task accuracy, response rate, response time, and hemodynamic response of the prefrontal lobe. The outcomes will be evaluated at baseline, and at 6 and 12 weeks after subject allocation. Discussion: This clinical pilot trial is designed to determine the feasibility of acupuncture as an effective and safe treatment for improving cognitive function in patients with MCI. Results of this study may provide guidance for future larger-scale clinical trials. Trial registration: Clinical Research Information Service (CRIS), Republic of Korea: KCT0002451. Registered September 5, 2017. Keywords: Acupuncture, Functional near-infrared spectroscopy, Mild cognitive impairment

A 77-year-old professional gold craftsman ingested a white powder used in goldsmithing, mistaking the powder for a health supplement. He detected a strange taste and immediately fell sick, reported the incident to 911, and was taken to the emergency room. He died approximately 8.5 h post-ingestion despite treatment. There were no significant findings in the autopsy, the victim's heart blood sample, gastric contents, and the white powder the victim had taken were submitted to the department of forensic toxicology. Using scanning electron microscopy energy dispersive X-ray analysis, potassium and gold (Au) were detected in the white powder. Ion chromatography analysis detected cyanide. Concentrations of cyanide were 0.5 mg/L in heart blood and 13.3 mg/L in gastric contents. Qualitative and quantitative analyses of Au in the heart blood sample and gastric contents using inductively coupled plasma-optical emission spectrometry detected concentrations of 79.8 mg/L and 2010.1 mg/L, respectively. Au and cyanide synergistically enhance cytotoxicity through inhibition of detoxification and increasing intracellular accumulation. In the present case, the detected blood cyanide concentration was sub or minimally lethal, and the blood Au concentration was high. The cause of the victim's death was the combined toxicity of Au and cyanide., (© 2024 American Academy of Forensic Sciences.)

Lophophora is a member of the Cactaceae family, which contains two species: Lophophora williamsii and L. diffusa. Lophophora williamsii is an illegal plant containing mescaline, a hallucinogenic alkaloid. In this study, a novel method based on a single nucleotide polymorphism (SNP) assay was developed for identifying L. williamsii; this assay reliably detects SNPs within chloroplast DNA (rbcL, matK, and trnL-trnF IGS) and was validated for identifying Lophophora and L. williamsii simultaneously. The chloroplast DNA sequences from four L. williamsii and three L. diffusa plants were obtained and compared using DNA sequence data from approximately 300 other Cactaceae species available in GenBank. From this sequence data, a total of seven SNPs were determined to be suitable for identifying L. williamsii. A multiplex assay was constructed using the ABI PRISM ® SNaPshot™ Multiplex Kit (Applied Biosystems, Forster City, CA) to analyze species-specific SNPs. Using this multiplex assay, we clearly distinguished the Lophophora among 19 species in the Cactaceae family. Additionally, L. williamsii was distinguished from L. diffusa. These results suggest that the newly developed assay may help resolve crimes related to illegal distribution and use. This multiplex assay will be useful for the genetic identification of L. williamsii and can complement conventional methods of detecting mescaline., (© 2020 American Academy of Forensic Sciences.)

Hair is one of the key samples for judging drug abuse in the field of forensic science. However, few studies have examined synthetic cannabinoids and their metabolites in human hair. Synthetic cannabinoids are a class of chemicals that bind to cannabinoid receptors, but they differ structurally from the cannabinoids found in cannabis. They have been sold sprayed on dried, shredded plant material under brand names such as "Spice" since the 2000s. In South Korea, synthetic cannabinoids have been widely distributed since 2009 and many types detected up to now. Unlike traditional drugs such as methamphetamine and cannabis, the abuse trends of synthetic cannabinoids were variable by regions and changed according to the times. If new types of synthetic cannabinoids become popular which has been altered in some structures, it becomes difficult to identify using exist analytical method. Therefore, it is important to develop a new analytical method for synthetic cannabinoids currently being abused in society. In this study, we developed simultaneous analytical methods for the detection of 18 synthetic cannabinoids and 41 of their metabolites in authentic human hair samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Selectivity, linearity, limits of detection (LODs), limits of quantification (LOQs), precision, accuracy, matrix effect, recovery, and process efficiency were evaluated, and all results were acceptable. Additionally, the distribution of synthetic cannabinoids in the head hair of Korean drug abusers from 2016 to 2018 was investigated. Hair samples from 43 individuals suspected of synthetic cannabinoid use were provided by law enforcement agencies. The drugs detected most prevalently in the head hair of Korean drug abusers were AB-CHMINACA and JWH-210., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The aim of this study was to investigate whether the results of segmental hair analysis can be used to estimate patterns of methamphetamine (MA) use. Segmental hair analysis for MA and amphetamine (AP) was performed. Hair was cut into the hair root, consecutive 1 cm length segments and 1-4 cm length segments. Whole hair was also analyzed. The hair samples were incubated for 20 h in 1 mL methanol containing 1 % hydrochloric acid after washing the hair samples. Hair extracts were evaporated and derivatization was performed using trifluoroacetic anhydride in ethylacetate at 65 °C for 30 min. Derivatized extract was analyzed by gas chromatography/mass spectrometry. The 15 subjects consisted of 13 males and two females and their ages ranged from 25 to 42 (mean, 32). MA and AP concentrations in the whole hair ranged from 3.00 to 105.10 ng/mg (mean, 34.53) and from 0.05 to 4.76 ng/mg (mean, 2.42), respectively. Based on the analysis of the 1 cm length segmental hair, the results were interpreted in a way to distinguish between continuous use of MA (n = 10), no recent but previous use of MA (n = 3), and recent but no previous use of MA (n = 2). Furthermore, the individuals were interpreted as light, moderate, and heavy users based on concentration ranges previously published.