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BACKGROUND: Prefabricated myofunctional appliance can guide tooth eruption, improve dentition alignment, correct myofunctional disorders and harmful oral habits. However, its application to skeletal discrepancy may result in unsatisfactory tooth inclination. This study aimed to construct a novel appliance with overjet design to avoid this side effect and investigated its shape and mechanical changes under occlusion using three-dimensional finite element method. METHODS: We established three samples of prefabricated myofunctional appliances. The first one was edge to edge without overjet, and the outer shield of both jaws were flattened. The second one was 3 mm overjet with stepped the outer shield. The last one was 3 mm overjet, and the outer shield of both jaws were flatted, which meant the front wall of lower jaw was strengthened with bumper, termed as lower bumper. A complete dentition model was applied to the study. 150 N occlusal force was applied to each type of appliance and the deformation displacement and the changes in stress was recorded. RESULTS: The deformation was significant in the incisors regions, especially in the vertical and lateral dimensions. The maximum displacements of 3 mm overjet with step shield group were 7.08 mm (vertical), 3.99 mm (lateral), and 2.90 mm (sagittal), while it decreased to 3.92 mm(vertical), 1.94 mm (lateral), and 1.55 mm (sagittal) in overjet with bumper group. Moreover, the upper molar regions exhibited higher vertical and sagittal displacement in 3 mm overjet with step shield group, which were 3.03 mm (vertical) and 1.99 mm (sagittal), and the bumper design could decrease the maximum displacement to 1.72 mm (vertical) and 0.72 mm (sagittal). In addition, the Von Mises stress of appliances was analyzed, and results indicated that 3 mm overjet with step shield generated higher stress than other groups, with the maximum Von Mises stress was 0.9387 MP, which were 0.5858 and 0.5657 MP in edge to edge group and 3 mm overjet with lower bumper group, respectively. CONCLUSION: The prefabricated myofunctional appliances may cause deformation during occlusion. Compared to step shield group, the application of lower bumper exhibited better resistance to occlusal force.
Subject(s)
Finite Element Analysis , Orthodontic Appliance Design , Humans , Myofunctional Therapy/instrumentation , Myofunctional Therapy/methods , Bite Force , Imaging, Three-Dimensional/methods , Overbite/therapy , Stress, Mechanical , Mandible , Incisor , Biomechanical PhenomenaABSTRACT
The recently emerged coronavirus disease COVID-19 has now evolved into a global pandemic. Early detection is crucial for its effective control. Nucleic acid testing for viral pathogen and serological testing for host antibodies are playing important roles in current COVID-19 diagnosis. However, while nucleic acid testing is complicated, facility-restricted and time-consuming, antibody testing may result in high rates of false-negative diagnoses, especially during the early stages of viral infection. Thus, a more rapid and reliable test for both early COVID-19 diagnosis and whole-population screening is urgently needed. Here, we developed a novel nanozyme-based chemiluminescence paper assay for rapid and high-sensitive testing of SARS-CoV-2 spike antigen. Our paper test uses a newly established peroxidase-mimic Co-Fe@hemin nanozyme instead of natural HRP that catalytically amplifies the chemiluminescent signal, allowing for target concentrations to be as low as 0.1 ng/ml. Furthermore, our nanozyme-based chemiluminescence test exhibits a linear range that is 32-fold wider compared to ELISA tests. Importantly, testing is completed in less than 16 min, compared to 1-2 h required for ELISA or nucleic acid tests. Critically, signal detection is feasible using a smartphone camera. Ingredients for our test are simple and readily available, rendering overall cost considerably lower than those used in current diagnoses. In conclusion, our novel test provides a high-sensitive, point-of-care testing (POCT) approach for SARS-CoV-2 antigen detection, which should greatly increase current early screening capacities for suspected infections, and considerably lower demand for national healthcare resources.
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Objective To investigate the changes of visual acuity,fundus changes,and serum vitamin D concentration in diabetic retinopathy patients treated with metformin,and to evaluate its clinical efficacy.Methods Totally 80 cases (160 eyes) patients with background diabetic retinopathy were included in the study,and were divided into observation group (metformin + Pancreatic Kininogenase Enteric-coated Tablets) and control group (Pancreatic Kininogenase Enteric-coated Tablets) according to the different treatment methods used for 3 months.Fundus fluorescein angiography was used to evaluate the improvement of the fundus lesions.The serum levels of vitamin D were measured with electrochemiluminescence immunoassay (ECLIA).Results After 3 months of treatment,serum vitamin D concentration of the observation group increased,and the differences were statistically significant (P ＜ 0.05) when compared to before treatment.However,3 months after treatment,serum vitamin D levels of the control group increased slightly,but the difference was not statistically significant (P ＞ 0.05).The total effective rate of fundus improvement in the observation group and the control group was 70％ and 55％,respectively.There was significant difference between the two groups in the improvement of fundus (P ＜ O.05).Conclusions Metformin has an adjunctive effect on background diabetic retinopathy,and the increase of serum vitamin D may be one of the mechanisms of metformin in improving diabetic retinopathy.
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Objective To explore the role of transforming growth factor-β1/serum and glucocorticoid induced kinase 1 (TGF-β1/SGK1) signaling pathway in diabetic nephropathy (DN).Methods Totally 60 clean grade healthy male Sprague-Dawley (SD) rats were divided into normal control (Con group,n =20) and diabetic model group (diabetic group,n =40).Type 2 diabetic animal model was induced by intraperitoneal injection of streptozotocin (STZ,45 mg/kg) to SD rats.Half of rats in each group were sacrificed after implemented for 4 weeks and 8 weeks,respectively.Fasting glucose,serum urea and creatinine,as well as urine protein in 24 h were detected.Pathological changes of rats' kidney cortex tissue were examined by hematoxylin-eosin staining.The expression of SGK1 was detected by immunohistochemistry in renal tissue.The mRNA level of SGK1 was analyzed by real-time polymerase chain reaction (PCR).The protein expression of TGF-β1 and SGK1 were determined by Western blotting.Results Compared to the control group,the blood glucose of the diabetic group rats was significantly increased,kidney hypertrophy index,serum urea and creatinine,24 h urine volume and urinary microalbumin as well as kidney index were significantly higher (P ＜0.05).The mRNA expressed of SGK1,protein expression of TGF-β1 and SGK1 were also increased obviously in the renal cortex of diabetic rats (all P ＜ 0.05 vs Control).Conclusions TGF-β1/SGK1 signaling pathway is closely related to the TIF damage of kidney cortex in diabetic rats.
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In this paper, a simple mathematical model depicting blood flow in the deforming porous channel is developed with an emphasis on the permeability property of the blood vessel and slip boundary based on Beavers and Joseph slip condition. In this study, the blood is represented by a micropolar fluid. With such an ideal model, the governing equations are reduced to ordinary ones by introducing suitable similar transformations. Homotopy analysis method is employed to obtain the expressions for velocity and microrotation fields. Graphs are sketched for some values of parameters such as slip coefficient and expansion ratio, and the associated dynamic characteristics are analysed in detail.
Subject(s)
Hemodynamics , Models, Cardiovascular , Permeability , Porosity , RotationABSTRACT
Objective To investigate the effects of alpha lipoic acid on patients with diabetic retinopathy (DR),explore the possible mechanisms,and provide experimental evidence for the treatment of DR with lipoic acid.Methods Totally 75 DR patients were randomly divided into control group and treatment group.Patients in control group received the standard hypoglycemic treatment,antihypertensive therapy,and other comprehensive treatment.Patients from the treatment group were treated with alpha lipoic acid 600 mg + 250 ml 0.9％ sodium chloride injection additionally,avoiding light intravenous therapy,for a total of 4 weeks.Before and after treatment,fundus fluorescein angiography and visual inspection were detected in two groups.In addition,serum level of asymmetric dimethylarginine (ADMA) were detected with high performance liquid chromatography,serum lipid peroxidation product malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were detected to reflect the in vivo oxidative stress before and after treatment in two groups.Results Compared to the control group,visual acuity was improved significantly (P ＜ 0.05),and total efficiency of ocular lesions-improved was increased significantly (84.21％ vs 40.54％,x2 =15.28,P ＜ 0.01).Serum levels of endogenous inhibitor of nitric oxide synthase ADMA [(0.32 ±0.13) μmol/L vs (0.51 ± 0.26) μmol/L,P ＜ 0.05] and MDA [(3.22 ± 0.90) nmol/L vs (5.13 ± 0.42) nmol/ml,P ＜ 0.05] were significantly decreased,while SOD levels [(72.68 ± 1.31) U/ml vs (53.16 ± 1.54) U/ml,P ＜0.05] were significantly increased in DR patients after alpha lipoic acid treatment.Conclusions Alpha lipoic acid had some therapeutic effects for DR patients,which mainly lied in the improvement of visual acuity and eye disease,might be related to the decrease of oxidative stress and serum level of endogenous nitric oxide synthase (NOS) inhibitor ADMA.
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@#Objective To describe the results of the Universal Newborn Hearing Screening (UNHS) in Beijing in 2010; and investigatethe factors related with the results. Methods The result of the UNHS investigated by 106 maternity hospitals were reported. These hospitalswere investigated with the self-made questionnaire. Results In 2010, 159888 infants (91.99%) were screened in 106 maternity hospitals inBeijing as the 1st stage UNHS. 10.32% of them failed OAE tests. 72.30% received the 2nd stage UNHS and 13.27% of them failed testsagain. The referral rate was 0.99% in the end. The screening rate of both the 1st and 2nd stage was more in the newborn with Beijing householdregistration than in those with other household registration, as well as the hospitals in urban than in rural areas. For the rate fail in the1st stage UNHS, it was more in hospitals in urban than in rural areas, with distortion product otoacoustic emission (DPOAE) than with transientevoked otoacoustic emissions (TEOAE), by the bed than in the special room, and screening only once than screening again. ConclusionThe quality of UNHS is as high as in the developed countries in the newborn with Beijing household registration. To further improvethe screening rate, it is important to focus on the newborn with other household registers and the hospitals in rural areas. The instrument, personnelqualifications, environment and operation need to be further standardized.
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@#Objective To study the universal newborn hearing screening (UNHS) results obtained in Beijing from 2007 to 2010 and to evaluate the index of hearing screening in Beijing. Methods The newborn born in Beijing just from October 1, 2007 to September 30, 2010 were selected and their hearing screening and diagnosis data were retrospectively collected. Results From 2007 to 2010, 470537 infants (90.2%) were screened in Beijing as 1st stage UNHS. 43019(9.1%) failed otoacoustic emission (OAE) tests. 31009 infants (72.8%) were screened in 2nd stage UNHS and 4568 failed tests. 1262 infants were referred for more testing and 1087 of them were diagnosed regularly.501infants were normal. 266 infants were finally diagnosed with single hearing loss and 303 infants were diagnosed with binaural hearing loss. 61infants were diagnosed with severe binaural hearing loss. Conclusion Establishment of the perfect newborn hearing screening system and advanced information system, and follow-up for the suspected children actively by doctors of community health care unit facilitate to improve UNHS.
