OBJECTIVE: To predict the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training based on the modified Wright learning curve model, then to analyze and applicate the learning curve. METHODS: Twelve graduate students participating in standardized dental resident training were selected to prepare the resin maxillary central incisors on phantom head simulators for all ceramic crowns 4 times. The results of preparation were evaluated by 3 prosthetic experts with at least 10 years' experience focusing on the reduction, contour, taper, shoulder, finish line, margin placement, adjacent tooth injury, and preparation time for tooth preparation. The learning rate of tooth preparation was calculated by scores of tooth preparation of 4 times. The learning curve of tooth preparation was predicted based on the modified Wright learning curve model. According to the criteria of standardized training skill examinations for dental residents in Beijing, 80 was taken as the qualified standard score. The minimum training times for tooth preparation to satisfy the qualified standard score (80) was calculated, to analyze the characteristics of learning curve and evaluate the effectiveness of tooth preparation. RESULTS: The scores of 4 tooth preparation were 64.03±7.80, 71.40±6.13, 74.33±5.96, and 75.98±4.52, respectively. The learning rate was (106±4)%, which showed the learning curve an upward trend. There were no significant differences between the qualified standard score and the predicted scores of tooth preparation from the 5^th preparation to the 13^th preparation (P > 0.05). The predicted score of the 14^th preparation was higher than the qualified standard score (P < 0.05). CONCLUSION The trend of the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training is upward, which predicts the minimum training times higher than the qualified standard score is 14 times.
Humans ; Tooth Preparation, Prosthodontic/methods* ; Incisor ; Learning Curve ; Crowns ; Tooth Preparation ; Ceramics ; Dental Porcelain ; Dental Prosthesis Design

In the past 37 years, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) has undergone various major transmission routes in China, with the world most complex co-circulating HIV-1 subtypes, even the prevalence is still low. In response to the first epidemic outbreak of HIV in injecting drug users and the second one by illegal commercial blood collection, China issued the Anti-Drug Law and launched the Blood Donation Act and nationwide nucleic acid testing, which has avoided 98,232 to 211,200 estimated infections and almost ended the blood product-related infection. China has been providing free antiretroviral therapy (ART) since 2003, which covered >80% of the identified patients and achieved a viral suppression rate of 91%. To bend the curve of increasing the disease burden of HIV and finally end the epidemic, China should consider constraining HIV spread through sexual transmission, narrowing the gaps in identifying HIV cases, and the long-term effectiveness and safety of ART in the future.
Acquired Immunodeficiency Syndrome/prevention & control* ; China/epidemiology* ; Disease Outbreaks ; HIV Infections/prevention & control* ; Humans ; Prevalence

Background: Cardiopulmonary resuscitation (CPR) strategies in COVID-19 patients differ from those in patients suffering from cardiogenic cardiac arrest. During CPR, both healthcare and non-healthcare workers who provide resuscitation are at risk of infection. The Working Group for Expert Consensus on Prevention and Cardiopulmonary Resuscitation for Cardiac Arrest in COVID-19 has developed this Chinese Expert Consensus to guide clinical practice of CPR in COVID-19 patients. Main recommendations: 1) A medical team should be assigned to evaluate severe and critical COVID-19 for early monitoring of cardiac-arrest warning signs. 2) Psychological counseling and treatment are highly recommended, since sympathetic and vagal abnormalities induced by psychological stress from the COVID-19 pandemic can induce cardiac arrest. 3) Healthcare workers should wear personal protective equipment (PPE). 4) Mouth-to-mouth ventilation should be avoided on patients suspected of having or diagnosed with COVID-19. 5) Hands-only chest compression and mechanical chest compression are recommended. 6) Tracheal-intubation procedures should be optimized and tracheal-intubation strategies should be implemented early. 7) CPR should be provided for 20-30 min. 8) Various factors should be taken into consideration such as the interests of patients and family members, ethics, transmission risks, and laws and regulations governing infectious disease control. Changes in management: The following changes or modifications to CPR strategy in COVID-19 patients are proposed: 1) Healthcare workers should wear PPE. 2) Hands-only chest compression and mechanical chest compression can be implemented to reduce or avoid the spread of viruses by aerosols. 3) Both the benefits to patients and the risk of infection should be considered. 4) Hhealthcare workers should be fully aware of and trained in CPR strategies and procedures specifically for patients with COVID-19.

Huperzine A is a potent,reversible,and blood-brain barrier permeable acetylcholinesterase irhibitor.The aim of this study was to compare the pharmacokinetics,tolerability,and bioavailability of two formulations with the established reference formulation of huperzine A in a fasting,healthy Chinese male population.This was a randomized,single-dose,3-period,6-sequence crossover study.The plasma concentrations of huperzine A were determined by liquid chromatography tandem mass spectrometry.Tolerability was assessed based on subject interview,vital sign monitoring,physical examination,and routine blood and urine tests.The mean (SD) pharmacokinetic parameters of the reference drug were Cmax,1.550 (0.528) ng/mL;t1/2,12.092 (1.898) h;AUC0-72h,17.550 (3.794) ng.h/mL.Those of the test formulation A and test formulation B were Cmax,1.412 (0.467),1.521 (0.608) ng/mL;t1/2,12.073 (2.068),12.271 (1.678) h;AUC0-72h,15.286 (3.434) ng.h/mL,15.673 (3.586) ng.h/mL.The 90％ confidence intervals for the AUC0-72h and Cmax were between 0.80 and 1.25.No adverse events were reported by the subjects or found with results of clinical laboratory test.The test and reference products met the regulatory criteria for bioequivalence in these fasting,healthy Chinese male volunteers.All three formulations appeared to be well tolerated.

Objective To investigate the value of ultrasonography in the diagnosis and differential diagno-sis of lymphoma and stromal tumor of the small intestine. Methods The clinical characteristics and ultrasound findings of 36 patients with small intestine lymphoma and 69 patients with small intestine stromal tumor confirmed pathologically in Cancer Hospital of Chinese Academy of Medical Sciences between January 2009 and January 2016 were retrospectively analyzed and compared. Results There were statistically significant differences in echotexture,presence of echoless area,intratumoral gas,and ultrasonographic pattern between small intestine lymphoma and small intestine stromal tumor( all P ﹤0. 001 ),whereas no statistically significant difference in clinical characteristics,lesion size,contour,or lobulated mass. On ultrasound,small intestine lymphoma mainly demonstrated as infiltrative or mass-forming type,with homogeneous echotexture without cystic necrotic area;while small intestine stromal tumor demonstrated as mass-forming type with heterogeneous echotexture and cystic necrotic area. Conclusions Lymphoma and stromal tumor of the small intestine both have some characteristic ultrasound features,the difference between which may help in the diagnosis and differential diagnosis of these two conditions.

This study is to develop a sensitive method by using reversed-phase high performance liquid chromatography coupled with UV detector (HPLC-UV) to simultaneously determine four bioactive compounds, iriflophenone 3-C-beta-D-glucoside, iriflophenone 3,5-C-beta-D-diglucoside, mangiferin, and iriflophenone 2-O-alpha-L-rhamnoside in the leaves of Aquilaria sinensis. An Agilent Zorbax SB-C, column (4, 6 mm x 250 mm, 5 microm) was used, and the gradient elution was performed with mobile phase of 0.1% aqueous phosphoric acid and acetonitrile at a flow rate of 1 mL x min(-1). The detection wavelength was 280 nm, and the column temperature was 25 degrees C. The four marker compounds were well separated with good linearity (R2 > 0.9990), precision, stability and repeatabili y. The-recovery rates were in the range of 98.80%-101.39%. For 15 branch of the leaves, the contents of iriflophenone 3-C-beta-D-gluoside, iriflophenone 3,5-C-beta-D-diglucoside, mangiferin, and iriflophenone 2-O-alpha-L-rhamnoside were between 0.41-14.48, 0.72-3.85, 4.30-29.07, 0.24-5.06 mg, respectivley. This method is precise, accurate and reliable, which provides an efficient way for the quality control of the leaves of A. sinensis. This will promote the comprehensive usage of this plant.
Benzophenones ; analysis ; Chromatography, High Pressure Liquid ; methods ; Drugs, Chinese Herbal ; analysis ; Plant Leaves ; chemistry ; Spectrophotometry, Ultraviolet ; methods ; Thymelaeaceae ; chemistry ; Xanthones ; analysis

Ten compounds, including seven sesquiterpenes, two phenols and one phenylpropanoid, were isolated from the roots of Illicium majus by means of silica gel, ODS, Sephadex LH-20, and preparative HPLC. On analysis of MS and NMR spectroscopic data , their structures were established as cycloparviflorolide (1), cycloparvifloralone (2), tashironin (3), tashironin A (4), anislactone A(5), anislactone B (6), pseudomajucin (7), syringaldehyde (8), methyl-4-hydroxy-3, 5-dimethoxybenzoate (9), and (E)-3-methoxy-4,5-methylenedioxycinnamic alchol (10), respectively. Compounds 1-4 and 8-10 were first isolated from this plant. In the in vitro assays, at a concentration of 1.0 x 10(-5) mol x L(-1), compounds 5 and 6 were active against LPS induced NO production in microglia with a inhibition rate of 75.31% and 53.7%, respectively.
Drugs, Chinese Herbal ; analysis ; chemistry ; Illicium ; chemistry ; Organic Chemicals ; analysis ; chemistry ; Plant Roots ; chemistry

Objective:To investigate the expression of MMP-1 and PTEN protein in basal cell papilloma (BCP), as well as their correlation with skin photoaging. Methods:Immunohistochemistry technique via Elivison method was employed to measure the expres-sion of MMP-1 and PTEN protein in lesions from 50 cases of BCP on exposed areas, 50 cases on non-exposed areas, and 30 normal controls. We compared the differences among the three groups and analyzed the result. A total of 90 BCP cases on exposed areas were randomly divided into three groups. Titanium dioxide cream and placebo were respectively applied in the trial groups twice daily for 12 weeks, whereas the control group was non-administered. After 12 weeks, the MMP-1 in the lesions of the three groups was measured and compared. Results:The expression scores of MMP-1 on exposed areas were significantly higher than those in the control group (P<0.01). No significant difference was found between non-exposed areas and the control group (P>0.05). The expression scores of PTEN protein on exposed areas and on non-exposed areas were significantly lower than that in control group (P<0.01). The expression scores of MMP-1 in the group that used titanium dioxide were evidently lower than those in control group after 12 weeks (P<0.05). Conclu-sion:MMP-1 is overexpressed in BCP on exposed areas. PTEN protein is underexpressed in BCP of exposed areas and non-exposed ar-eas. Skin photoaging is a possible cause of BCP on exposed areas.

Phytochemical investigation was carried out on the seeds of Vigna umbellata. The 70% ethanol extract of the seeds of V. umbellata was subjected to silica gel, Sephadex LH-20, ODS column chromatographies and preparative HPLC. The structures of the isolated compounds were elucidated on the basis of NMR and ESI-MS spectroscopic data Eight compounds were obtained and identified as carboxyatractyligenin (1), 2beta-O-beta-D-glucopyranosyl-15alpha-hydroxy-kaur-16-ene-18,19-dicarboxylic acid (2), 2beta-O-(beta-D-glucopyranosyl) atractyligenin (3), 3R-O-[beta-L-arabinopyranosyl-(1-6) -beta-D-glucopyranosyl] oct-1-ene-3-ol (4), (6S, 7E, 9R) -roseoside (5), liriodendrin (6), resveratrol (7) and maltol (8). Compounds 1-7 were isolated from Vigna genus for the first time, and compound 8 was isolated from V. umbellata for the first time.
Fabaceae ; chemistry ; Seeds ; chemistry

OBJECTIVETo observe the effect of vascular endothelial growth factor (VEGF) on bone marrow-derived mesenchymal stem cell (MSC) proliferation and explore the signaling mechanism involved.

METHODSMSC culture was performed following the classical whole bone marrow adhering method. The characteristics of MSC were identified by induction of multi-lineage differentiation and flow cytometry for surface marker analysis (CD34, CD45, CD29, and CD90). Following the addition of 50 nmol/L wortmannin, 50 µmol/L PD98059, 30 µmol/L SB203580, 10 µmol/L H89, 20 µmol/L Y27632, 1 µmol/L rapamycin, 10 µmol/L straurosporine, 6 nmol/L Go6976, or 50 µmol/L Pseudo Z inhibitors in the cell culture, the MSC were treated with 20 ng/ml VEGF and the changes of the cell proliferation rate was measured with MTT assay.

RESULTSCultured MSC were capable of multi-linage differentiation and did not express VEGF-R, CD29 or CD90. Treatment with 20 ng/ml VEGF obviously promoted MSC proliferation, and this effect was inhibited partially by p38 mitogen-activated protein kinase (MAPK) inhibitor rapamycin, PD98059, SB203580, Go6976, and straurosporine.

CONCLUSIONSVEGF promotes MSC proliferation in close relation to the AKT-PKC pathway, in which PKC signal pathway may play the central role.

Animals ; Bone Marrow Cells ; cytology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Female ; Male ; Mesenchymal Stromal Cells ; cytology ; Protein Kinase C ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Vascular Endothelial Growth Factor A ; pharmacology