OBJECTIVEFrictions of Lock-loose brackets with ligated main wings or all six wings were measured as they slid along archwires in dry and artificial saliva environments. The Lock-loose brackets were then compared with traditional brackets and self-ligating brackets.

METHODSThe surface states of the stainless steel archwires were observed with atomic force microscopy before and after mechanical traction. The Lock-loose brackets, traditional brackets, and self-ligating brackets used in this study were composed of 0.406 4 and 0.457 2 mm stainless steel round archwires and 0.457 2 mm x 0.634 9 mm and 0.482 6 mm x 0.634 9 mm stainless steel rectangular archwires. Two different ligating methods were applied to the Lock-loose brackets, i.e., main wings ligated and all six wings ligated. Frictions were measured by using an electronic universal testing machine.

RESULTSNo significant differences were found between the roughness of different archwires before and after mechanical traction in different brackets (P > 0.05). When the main wings of the Lock-loose brackets were ligated, the frictions of the four different stainless steel archwires were close to zero, and the difference with frictions of traditional brackets was significant (P < 0.05). When using 0.457 2 mm x 0.634 9 mm rectangular archwires, maximum friction (P < 0.05; significantly different from those of other brackets) was reached when all six wings of the Lock-loose brackets were ligated. Frictions in the dry state were higher than those in the wet state (P < 0.05).

CONCLUSIONThe Lock-loose brackets can adjust the friction efficiently with different ligating methods, thus solving the problem of low friction and strengthening anchorage.

Friction ; Humans ; Materials Testing ; Microscopy, Atomic Force ; Orthodontic Appliance Design ; Orthodontic Brackets ; Orthodontic Wires ; Stainless Steel ; Surface Properties

OBJECTIVETo screen rare blood groups Fy(a-), s-, k-, Di(b-) and Js(b-) in an ethnic Zhuang population.

METHODSSequence-specific primers were designed based on single nucleotide polymorphism (SNP) sites of blood group antigens Fy(b) and s. A specific multiplex PCR system I was established. Multiplex PCR system II was applied to detect alleles antigens Di(b), k, Js(b)1910 and Js(b) 2019 at the same time. The two systems was were used to screen for rare blood group antigens in 4490 randomly selected healthy donors of Guangxi Zhuang ethnic origin.

RESULTSWe successfully made the multiplex PCR system I. We detected the rare blood group antigens using the two PCR system. There are five Fy(a-), three s(-), two Di(b-) in 4490 Guangxi zhuang random samples. The multiplex PCR system I has achieved good accuracy and stability. With multiplex PCR systems I and II, 4490 samples were screened. Five Fy(a-), three s(-) and two Di(b-) samples were discovered.

CONCLUSIONMultiplex PCR is an effective methods, which can be used for high throughput screening of rare blood groups. The rare blood types of Guangxi Zhuang ethnic origin obtained through the screening can provide valuable information for compatible blood transfusion. Through screening we obtained precious rare blood type materials which can be used to improve the capability of compatible infusion and reduce the transfusion reactions.

Blood Group Antigens ; genetics ; Duffy Blood-Group System ; genetics ; Genotype ; Humans ; Multiplex Polymerase Chain Reaction ; methods ; Receptors, Cell Surface ; genetics

【Objective】 To explore the application of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) in the genotyping of difficult blood typing samples, and to provide evidence for clinical blood transfusion. 【Methods】 Three ambiguous blood group samples, submitted to Shanghai Blood Center by Shanghai regional hospitals, were studied, of which Sample1 included the proband and his parents. Serological methods were used to perform blood group typing, direct antibody test, unexpected antibody screening and identification test. Blood group genotyping was performed by using the MALDI-TOF MS detection systeme stablished in our laboratory. Sanger sequencing was used to confirm gene mutation sites, and serological or flow methods were used to verify specific samples′ phenotype. 【Results】 Serological results indicated the existence of antibodies against high frequency antigens in sample 1 (including proband and her mother), 2 and 3. The genotyping results of MALDI-TOF MS showed that the proband of sample 1 was Di(a+ b+ ), her father was Di(a-b+ ), her mother was Di(a+ b-), sample 2 was p, and sample 3 was Jr(a-). Sequencing results of three samples were consistent with mass spectrometry typing results. Serological results showed that sample 2 had a p phenotype. The flow cytometry results suggested that sample 3 had a Jr(a-) phenotype. 【Conclusion】 For the first time, we applied MALDI-TOF MS technology to blood type genotyping of ambiguous clinical samples in China. Compared with other genotyping methods such as PCR-SSP, MALDI-TOF MS has the advantages of rapid detection, high throughput and high specificity, which would contribute to identification of difficult blood typing samples in the future, as well as rare blood group screening.

BackgroundsInsomnia is frequent in schizophrenia and is found to be negatively affected by stressful life events， psychotic symptoms and depressive disorder， while the relationship among the four remains understudied in community-dwelling patients with schizophrenia. ObjectiveTo analyze the effect of stressful life events on insomnia in community-dwelling patients with schizophrenia， and to explore the mediation effect of psychotic symptoms and depression， so as to provide references for the intervention of insomnia in community-dwelling patients with schizophrenia. MethodsFrom April to June 2023， a sample of 1 105 patients with schizophrenia attending 48 community health centers in Chengdu， Sichuan province and fulfilling the International Classification of Diseases， tenth edition （ICD-10） diagnostic criteria were included. All subjects were assessed using Stressful Life Event Scale （SLEs）， Athens Insomnia Scale （AIS）， Psychosis Screening Questionnaire （PSQ）， and Patient Health Questionnaire Depression Scale （PHQ-9）. Spearman correlation analysis was used to determine the correlation among the scales. Then the mediation model was constructed using Smart PLS 4.0， and tested with partial least squares algorithm and Bootstrap techniques. Results332 patients （30.05%） with community schizophrenia were found to have insomnia. AIS scores in patients with schizophrenia were positively correlated with the scores on SLEs， PSQ and PHQ-9 （r=0.165， 0.322， 0.554， P<0.01）. Stressful life events indirectly contributed to insomnia through both separate mediation path and chained mediation path of psychotic symptoms and depressive disorder， and the indirect effect size of 0.102， 0.372 and 0.190 was obtained， accounting for 10.46%， 38.15% and 19.49%， respectively. ConclusionThe stressful life events not only directly exert an impact on insomnia， but also indirectly contribute to insomnia through both the separate and chained mediation effect of psychotic symptoms and depressive disorder.