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OBJECTIVES@#The current study aimed to investigate the bonding properties of a novel low-shrinkage resin adhesive containing expanding monomer and epoxy resin monomer after thermal cycling aging treatment.@*METHODS@#Expanding monomer of 3,9-diethyl-3,9-dimethylol-1,5,7,11-tetraoxaspiro-[5,5] undecane (DDTU) as an anti-shrinkage additive and unsaturated epoxy monomer of diallyl bisphenol A diglycidyl ether (DBDE) as a coupling agent were synthesized. A blend of DDTU and DBDE at a mass ratio of 1∶1, referred to as "UE", was added into the resin matrix at the mass fraction of 20% to prepare a novel low-shrinkage resin adhesive.Then, the methacrylate resin adhesive without UE was used as the blank control group, and a commercial resin adhesive system was selected as the commercial control group. Moreover, the resin-dentin bonding and micro-leakage testing specimens were prepared for the thermal cycling aging treatment. The bonding strength was tested, the fracture modes were calculated, the bonding fracture surface was observed by scanning electron microscope (SEM), and the dye penetration was used to evaluate the tooth-restoration marginal interface micro-leakage. All the data were analyzed statistically.@*RESULTS@#After aging, the dentin bonding strength of the experimental group was (19.20±1.03) MPa without a significant decrease (P>0.05), that of the blank control group was (11.22±1.48) MPa with a significant decrease (P<0.05) and that of the commercial control group was (19.16±1.68) MPa without a significant decrease (P>0.05). The interface fracture was observed as the main fracture mode in each group after thermal cycling by SEM. The fractured bonding surfaces of the experimental group often occurred on the top of the hybrid layer, whereas those of the blank and commercial control groups mostly occurred on the bottom of the hybrid layer. Micro-leakage rating counts of specimens before and after thermal cycling were as follows: the experimental group was primarily 0 grade, thereby indicating that a relatively ideal marginal sealing effect could be achieved (P>0.05); meanwhile, the blank control group was primarily 1 grade, and the penetration depth of dye significantly increased after thermal cycling (P<0.05); the commercial control group was primarily 0 grade without statistical difference before and after thermal cycling (P>0.05), while a significant difference was observed between the commercial control group and experimental group after thermal cycling (P<0.05).@*CONCLUSIONS@#The novel low-shrinkage resin adhesive containing 20%UE exhibited excellent bonding properties even after thermal cycling aging treatment, thereby showing a promising prospect for dental application.
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Composite Resins , Dental Bonding , Dental Cements , Surface Properties , Resin Cements , Dentin-Bonding Agents , Dentin , Materials Testing , Microscopy, Electron, ScanningABSTRACT
Objective:To explore the application effect of progressive case teaching method based on core competency in standardized nursing training.Methods:A total of 63 nursing students rotated in department of neurosurgery from June 2020 to June 2022 were selected as the research objects and randomized into experimental group ( n=31) and control group ( n=32). The experimental group adopted the progressive case teaching method based on core competency, and the control group adopted the conventional teaching mode. The data was analyzed using SPSS 26.0 to conduct t-test or non-parametric test based on the data normality for comparing the theory results, objective structure clinical examination (OSCE) scores, core competency, self-directed learning ability scores, teaching satisfaction and nursing satisfaction of patients in two wards between the two groups. Results:The theoretical results ( t=4.74, P<0.001) and OSCE scores ( t=3.81, P<0.001) of the experimental group were better than those of the control group. The scores of core competency and autonomous learning ability ( t=4.32, P<0.001) of the experimental group were better than those of the control group. The teaching satisfaction score ( t=2.21, P=0.044) and patient satisfaction score ( t=2.92, P=0.011) of the observation group were better than those of the control group. Conclusion:The progressive case teaching method based on core competency can improve the post competency of nurses, and also improve the teaching satisfaction rate and patient satisfaction rate, which is worthy of being carried out in the subsequent teaching activities.
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Objective@#To investigate the effects of neonatal intensive care unit (NICU)-centered regional neonatal transport network (NTN) on the treatment of retinopathy of prematurity (ROP).@*Methods@#A retrospective analysis was conducted to analyze the transfer, treatment and outcomes of 406 preterm infants with ROP who were transferred to the Bayi Children's Hospital Affiliated to the Seventh Medical Center of PLA General Hospital via the NTN from July 2008 to December 2014. Independent sample t-test, Chi-square test and Mann-Whitney nonparametric test were used for statistical analysis.@*Results@#Among the 406 premature infants who were transferred to our hospital because of ROP, there were 257 males and 149 females with the gestational age of (29.5±1.9) weeks (24+5-36 weeks) and the birth weight of (1 234.8± 268.9) g (580-2 400 g). The age at transfer was (48.9±18.5) d (15-78 d) and the transport distance was (216.5±78.6) km (10-625 km). No death was reported during the transportation. Very preterm births and very low birth weight infants (VLBWI) accounted for 88.7% (360 cases) and 82.5% (335 cases), respectively. Lesions occurred in 1, 2 and 3 zones were detected in 98 (24.1%), 286 (70.4%) and 22 (5.4%) cases, respectively. Lesions of stage 1-5 were observed in 51 (12.6%), 156 (38.4%), 183 (45.1%), 12 (3.0%) and 4 (1.0%) cases. There were 186 cases (45.8%) with Plus lesions. A total of 252 cases (62.1%) underwent surgery which were achieving treatment standards, including 165 (65.5%) undergoing laser therapy, 93 (36.9%) receiving anti-vascular endothelial growth factor (VEGF) therapy, 16 (6.4%) having vitrectomy and two (0.8%) having scleral buckling. Eighteen infants were diagnosed with retinal structural abnormalities, among which 16 had retinal detachment before admission (12 in phase 4 and four in phase 5). Two without retinal detachment on admission developed to phase 4 after surgery. The incidence of retinal structural dysplasia was 0.9% (2/236) in infants receiving laser and/or anti-VEGF therapy in our hospital. Compared with the cured patients (n=234), those with retinal structural dysplasia (n=18) had a late transfer time [80 (38-270) vs 50 (19-150) d, Z=3.387, P<0.001].@*Conclusions@#The NICU-centered and regional transfer-based ROP treatment network provides timely and effective treatment for infants with ROP.
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Objective To investigate the effects of neonatal intensive care unit (NICU)-centered regional neonatal transport network (NTN) on the treatment of retinopathy of prematurity (ROP). Methods A retrospective analysis was conducted to analyze the transfer, treatment and outcomes of 406 preterm infants with ROP who were transferred to the Bayi Children's Hospital Affiliated to the Seventh Medical Center of PLA General Hospital via the NTN from July 2008 to December 2014. Independent sample t-test, Chi-square test and Mann-Whitney nonparametric test were used for statistical analysis. Results Among the 406 premature infants who were transferred to our hospital because of ROP, there were 257 males and 149 females with the gestational age of (29.5±1.9) weeks (24+5-36 weeks) and the birth weight of (1 234.8± 268.9) g (580-2 400 g). The age at transfer was (48.9±18.5) d (15-78 d) and the transport distance was (216.5±78.6) km (10-625 km). No death was reported during the transportation. Very preterm births and very low birth weight infants (VLBWI) accounted for 88.7% (360 cases) and 82.5% (335 cases), respectively. Lesions occurred in 1, 2 and 3 zones were detected in 98 (24.1%), 286 (70.4%) and 22 (5.4%) cases, respectively. Lesions of stage 1-5 were observed in 51 (12.6%), 156 (38.4%), 183 (45.1%), 12 (3.0%) and 4 (1.0%) cases. There were 186 cases (45.8%) with Plus lesions. A total of 252 cases (62.1%) underwent surgery which were achieving treatment standards, including 165 (65.5%) undergoing laser therapy, 93 (36.9%) receiving anti-vascular endothelial growth factor (VEGF) therapy, 16 (6.4%) having vitrectomy and two (0.8%) having scleral buckling. Eighteen infants were diagnosed with retinal structural abnormalities, among which 16 had retinal detachment before admission (12 in phase 4 and four in phase 5). Two without retinal detachment on admission developed to phase 4 after surgery. The incidence of retinal structural dysplasia was 0.9% (2/236) in infants receiving laser and/or anti-VEGF therapy in our hospital. Compared with the cured patients (n=234), those with retinal structural dysplasia (n=18) had a late transfer time [80 (38-270) vs 50 (19-150) d, Z=3.387, P<0.001]. Conclusions The NICU-centered and regional transfer-based ROP treatment network provides timely and effective treatment for infants with ROP.
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Objective To observe the efficacy and safety of intravitreal injection of ranibizumab in the treatment of retinopathy of prematurity (ROP).Methods Data from 49 consecutive ROP patients (95 eyes) including type Ⅰ pre-threshold,threshold and aggressive posterior ROP who had received anti-VEGF treatment for the first time in our hospital from June 2014 to August 2015 were collected.60 eyes from the 95 eyes were confined as the zone Ⅰ disease group,while the remaining 35 eyes as zone Ⅱ disease group.The difference of birth weight,gestational age,corrected gestational age,treatment effects,recurrence and re-treatment time between two groups were compared.0.025 mL ranibizumab (10 mg · mL-1) was injected through 1.5 mm puncture after corneal limbus by using 30G 1 mL injection syringe.At the end of the injection,tobramycin and dexamethasone ophthalmic ointment eye bag was used.After the injection of 3 days,the portable slit lamp and tonometer were used to observe the intraocular pressure,intraocular hemorrhage and endophthalmitis.The indirect ophthalmoscope was used to observe the retinal vascular tortuosity and ridge regression of lesion expansion at 1 week after treatment.At the same time,the systemic adverse reactions related to treatment were observed.Results After receiving ranibizumab treatment for the first time,93 eyes (95.9％) exhibited ROP regression after single injection,including 58 eyes in zone Ⅰ disease group,35 eyes in zone Ⅱ disease group.There was no statistical difference between two groups (P ＞ 0.05).22 eyes required additional anti-VEGF injection or laser treatment for ROP recurrence,including 17 eyes in zone Ⅰ disease group,5 eyes in zone Ⅱ disease group.There was statistical difference between two groups (P ＜0.05).The time from recurrence to re-treatment was (6.50 ±2.54) weeks,which in zone Ⅰ disease group was (6.44 ± 2.74) weeks and in zone Ⅱ disease group was (6.67 ± 2.31)weeks,there was no statistical difference between two groups (P ＞ 0.05).No local or systemic adverse events associated with the treatment or drug was observed within the following period.Conclusion Intravitreal injection of ranibizumab is an effective and well tolerated method for zone Ⅰ and zone Ⅱ ROP,but the recurrence rate is high.There Is no local or systemic adverse events associated with the treatment or drug.
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Oxalic acid (OA) is inhibitory to many fungal plant pathogens. To further characterize the molecular mechanism of OA involved in fungal pathogenesis, OA insensitive mutants were screened from a chemical inducible Arabidopsis mutant library (about 6000 lines) using MS medium (calcium free) containing 1.2 mmol/L OA and 10 micromol/L estradiol. Harvested putative mutants were collected separately. Individual lines of mutants were screened again on modified MS medium containing OA. Mutants D33, D74, D154, D282 and D630 with enhanced OA resistance were obtained. The T-DNA flanking sequences were amplified by TAIL-PCR. The sequences were blasted against TAIR database. The result indicated that the T-DNA of mutant D33 was inserted between At2g39720 (zinc finger) and At2g39730 (Rubisco activase), and the T-DNA junctions of the other four mutants were the same, all inserted in the same site of the first intron of At5g10450 (14-3-3 protein GF14 lambda).
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Arabidopsis , Genetics , Culture Techniques , Drug Tolerance , Genetics , Mutation , Oxalic Acid , Pharmacology , Plants, Genetically Modified , GeneticsABSTRACT
Objective To investigate the electrophysiological properties of retinal ganglion cells(RGCs) in Long Evans rats during different postnatal developmental stages so as to explore the intracellular mechanism of retinal neuron maturation. Methods Whole cell patch clamp recordings of RGCs in acute retinal slices of Long Evans rats (postnatal days 3 to 31) were performed. Depolarizing current pulses of different densities were inflicted on RGCs to evoke action potentials(AP) . Results A total of 94 RGCs, single spike cells, transient and sustained cells, were acquired in 33 rats. The proportion of the three types of TGCs was different. There was significant difference in electrophysiological properties. Conclusion During the period of postnatal development, gradually matured electrophysiological properties of RGCs and differences in amplitudes and frequencies of AP suggest that different types of RGCs may play different roles in coding and transmitting spatial and temporal information.
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Objective To study the membrane properties of rat retinal ganglion cells during postnatal development, including the passive membrane properties and the action potentials evoked by depolarizing current injections and the relationship between the membrane properties and ages. Methods Whole cell patch clamp recordings of the retinal ganglion cells (RGCs) in retinal slices of postnatal rats (age ranging from postnatal days 7 to 30) were performed. Results (1) A total of 112 RGCs were recorded from postnatal rats. (2) The electrophysiological properties of RGCs changed significantly during development. The excitability of RGCs increased in an age-dependent manner. There was significant difference between before-eye-opening group(P7-13d) and after-eye-opening group(P14-30d) . (3) Three different discharge patterns of RGCs in response to sustained depolarizing current pulses were recorded: single-spike firing, transient firing and sustained firing. During development, retinal ganglion cells of rats exhibited pronounced changes in the discharge patterns(P
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Objective To observe the electrophysiological and morphological features of retinal ganglion cells (RGCs) in rats, and investigate its effect on the visual signal conduction. Methods Whole cell recordings were obtained from 112 RGCs of 30 rats at the age of 7-30 days. Resting membrane potential (RMP) was recorded, and input impedance was noted after given 2 mV hyperpolarizing current by voltage clamp. The action potential (AP) was induced by deplorizing current at different densities. The histological staining was actualized by injecting with biotin into the RGCs, and the diameter of the cells was measured. Results Three different discharge patterns of RGCs in response to maintained depolarizing currents were recorded: single spike (25 RGCs), transient firing (40 RGCs), and sustained firing (47 RGCs). The diameter was 14-16 ?m in 57.14% transient firing RGCs, and 10-12 ?m in 62.50% sustained firing RGCs. The maximum frequency of AP of sustained firing RGCs was significantly higher than that of transient firing RGCs (P