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1.
Front Plant Sci ; 15: 1371435, 2024.
Article in English | MEDLINE | ID: mdl-38660445

ABSTRACT

Introduction: Low-light-stress is a common meteorological disaster that can result in slender seedlings. The photoreceptors play a crucial role in perceiving and regulating plants' tolerance to low-light-stress. However, the low-light-stress tolerance of cucumber has not been effectively evaluated, and the functions of these photoreceptor genes in cucumber, particularly under low-light-stress conditions, are not clear. Methods: Herein, we evaluated the growth characteristics of cucumber seedlings under various LED light treatment. The low-light-stress tolerant cucumber CR and intolerant cucumber CR were used as plant materials for gene expression analysis, and then the function of CsCRY1 was analyzed. Results: The results revealed that light treatment below 40 µmol m-2 s-1 can quickly and effectively induce low-light-stress response. Then, cucumber CR exhibited remarkable tolerance to low-light-stress was screened. Moreover, a total of 11 photoreceptor genes were identified and evaluated. Among them, the cryptochrome 1 (CRY1) had the highest expression level and was only induced in the low-light sensitive cucumber CS. The transcript CsaV3_3G047490.1 is predicted to encode a previously unknown CsCRY1 protein, which lacks 70 amino acids at its C-terminus due to alternative 5' splice sites within the final intron of the CsCRY1 gene. Discussion: CRY1 is a crucial photoreceptor that plays pivotal roles in regulating plants' tolerance to low-light stress. In this study, we discovered that alternative splicing of CsCRY1 generates multiple transcripts encoding distinct CsCRY1 protein variants, providing valuable insights for future exploration and utilization of CsCRY1 in cucumber.

2.
Plant Physiol Biochem ; 208: 108515, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38484681

ABSTRACT

Pericarp color is a prominent agronomic trait that exerts a significant impact on consumer and breeder preferences. Genetic analysis has revealed that the pericarp color of bitter gourd is a quantitative trait. However, the underlying mechanism for this trait in bitter gourd remains largely unknown. In the present study, we employed bulked segregant analysis (BSA) to identify the candidate genes responsible for bitter gourd pericarp color (specifically, dark green versus white) within F2 segregation populations resulting from the crossing of B07 (dark green pericarp) and A06 (white pericarp). Through genomic variation, genetic mapping, and expression analysis, we identified a candidate gene named McPRR2, which was a homolog of Arabidopsis pseudo response regulator 2 (APRR2) encoded by LOC111023472. Sequence alignment of the candidate gene between the two parental lines revealed a 15-bp nucleotide insertion in the coding region of LOC111023472, leading to a premature stop codon and potentially causing a loss-of-function mutation. qRT-PCR analysis demonstrated that the expression of McPRR2 was significantly higher in B07 compared to A06, and it was primarily expressed in the immature fruit pericarp. Moreover, overexpression of McPRR2 in tomato could enhance the green color of immature fruit pericarp by increasing the chlorophyll content. Consequently, McPRR2 emerged as a strong candidate gene regulating the bitter gourd pericarp color by influencing chlorophyll accumulation. Finally, we developed a molecular marker linked to pericarp color, enabling the identification of genotypes in breeding populations. These findings provided valuable insights into the genetic improvement of bitter gourd pericarp color.


Subject(s)
Momordica charantia , Momordica charantia/genetics , Plant Breeding , Chromosome Mapping/methods , Phenotype , Chlorophyll
3.
J Org Chem ; 89(1): 373-378, 2024 Jan 05.
Article in English | MEDLINE | ID: mdl-38096478

ABSTRACT

A highly efficient and regioselective method for constructing functionalized conjugated enals via the Tf2O-mediated tandem reaction of enaminones with thiophenols has been described. Chain products with excellent stereoselectivity could be obtained through substrate regulation. Additionally, a feasible method for synthesizing ß-naphthalaldehydes through PhSO2Na/DABCO promoting hydrogen atom transfer process has also been reported here. Mechanism studies have shown that 2-formyl vinyl triflate 8 and sulfonylated enal 9 were the key intermediates in this process.

4.
Chemosphere ; 346: 140595, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37951392

ABSTRACT

Titanium dioxide (TiO2)-based photocatalysts have gained increasing attention for their versatile applications in organic degradation, hydrogen production, air purification, and CO2 reduction. Various TiO2-based heterojunction structures, including type I, type II, Schottky junction, Z-scheme, and S-scheme, have been extensively studied. The current research frontier is centered on the engineering modifications of TiO2-based nanoheterojunction photocatalysts, such as defect engineering, morphological engineering, crystal phase/facet engineering, and multijunction engineering. These modifications enhance carrier transport, separation, and light absorption, thereby improving the photocatalytic performance. Remarkably, this aspect has been less addressed in existing reviews. This review aims to fill this gap by focusing on the engineering modifications of TiO2-based nanoheterojunction photocatalysts. We delve into specific topics like oxygen vacancies, n-p homojunctions, and double defects. The review also systematically discusses the applications of multidimensional heterojunctions and examines carrier transport pathways in heterophase/facet junctions and their interactions with heterojunctions. A comprehensive summary of multijunction systems, including multi-Schottky junctions, semiconductor-based heterojunction-attached Schottky junctions, and multisemiconductor-based heterojunctions, is presented. Lastly, we outline future perspectives in this promising research field. This paper will assist researchers in constructing more efficient TiO2-based nanoheterojunction photocatalysts.


Subject(s)
Oxygen , Semiconductors
5.
J Dent Educ ; 87(12): 1636-1644, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37712298

ABSTRACT

OBJECTIVES: This paper aims to explore the successful implementation of online postgraduate admissions re-examination in China, specifically focusing on the Modified Objective Structured Examination (MOSE). It introduced the specific practice of the online postgraduate admissions re-examination in China and investigated the perceptions of applicants, postgraduate supervisors and admissions staffs about the online MOSE re-examination. METHODS: Surveys were administrated 3 years after the implementation of online MOSE postgraduate admissions re-examination in China. Separate surveys were conducted with applicants, postgraduate supervisors, and admissions staff members to gather their opinions and suggestions regarding the online MOSE re-examination. RESULTS: A total of 65 applicants, 43 postgraduate supervisors and seven admissions staff members completed the surveys. Over 80% of the applicants agreed that the online MOSE comprehensively evaluated their medical humanities, communication, medical knowledge, and overall competence. Furthermore, 89.30% of postgraduate supervisors believed that the students recruited through online MOSE were either "not significantly different," "better," or "much better" compared to those recruited through on-site re-examination. Admissions staff members also expressed a favorable view of online MOSE re-examination. CONCLUSION: The online MOSE re-examination is an effective, convenient, and affirmative evaluation method for postgraduate admissions re-examination.


Subject(s)
Humanities , Students , Humans , Universities , China , Surveys and Questionnaires
6.
Org Lett ; 25(7): 1192-1197, 2023 Feb 24.
Article in English | MEDLINE | ID: mdl-36779678

ABSTRACT

A cost-effective, highly regioselective and metal-free version for the synthesis of indolizine derivatives by means of Tf2O-mediated cascade reaction of pyridyl-enaminones and thiophenols/thioalcohols under mild reaction conditions has been reported. Diverse electron-rich indolizine derivatives could be obtained in up to 94% yield via the selective 1,4-addition of vinyl iminium triflate tandem cyclization/aromatization, which allowed the simultaneous construction of C-N and C-S/and one example of C-Se bonds.

7.
J Esthet Restor Dent ; 35(2): 303-308, 2023 03.
Article in English | MEDLINE | ID: mdl-36573304

ABSTRACT

OBJECTIVE: This study aimed to explore the influence of smile esthetics on the quality of life in a Han Chinese population. METHODS: A total of 110 Han Chinese volunteers (52 males and 58 females, mean age 26.7 years) were recruited, and frontal images of their smiles were collected. A photoediting program was used to evaluate the following components of smile esthetics: the buccal corridor ratios, the angle between the interpupillary and commissural lines, the number of visible teeth, and width-to-length ratios of the maxillary central incisors. Oral health-related quality of life (OHRQoL) in these volunteers was evaluated using the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) and Oral Health Impact Profile-14 (OHIP-14). Statistical analyses were performed by using Pearson's correlations and multiple linear regression (α = 0.05). RESULTS: Compared to males, females scored higher on psychological impact (p = 0.017). Moreover, the number of visible teeth had a significant effect on social impact, psychological impact and esthetic concern (all p < 0.05). However, the buccal corridor ratios, the angle between the interpupillary and commissural lines, and the width-to-length ratios of the maxillary central incisor did not correlate with the OHRQoL (all p > 0.05). CONCLUSIONS: The number of visible teeth significantly influenced the quality of life in a Han Chinese population. Smile esthetics had a significantly greater psychological impact on females than males. CLINICAL SIGNIFICANCE: This study highlights the effects of smile esthetics on the quality of life in a Han Chinese population. Female patients may raise more esthetic concerns in clinical practice.


Subject(s)
Esthetics, Dental , Quality of Life , Smiling , Adult , Female , Humans , Male , East Asian People , Incisor/anatomy & histology
8.
Front Oral Health ; 3: 994613, 2022.
Article in English | MEDLINE | ID: mdl-36407658

ABSTRACT

Dental graduates have a variety of career-path choices. After graduation, they may join private dental practice, government- or hospital-based dental care services, research groups, academia, business or industry. With globalization and frequent international exchange, dental graduates nowadays can explore careers outside their home country. However, dental education systems and job opportunities vary widely across different regions and countries. Diversity of accreditation in dental education, different licensure requirements, and lack of global competencies in dental care often limit the globalization, operation and survival of dental practice and education worldwide. The requirements for professional education and practice can be quite diverse, and these differences will be barriers to dental graduates seeking career development outside their home home country. Fresh dental graduates have minimal experience in job hunting. More specifically, they are unfamiliar with potential career paths. This paper was based on the 4th trilateral symposium 2022 organized by The University of Hong Kong, Tohoku University, and Fujian Medical University, which offered a lecture to discuss career paths for dental graduates in Hong Kong, Japan, and mainland China. The aim of this paper was to provide dentists, particularly fresh graduated dental students, with practical insight into different career paths in Hong Kong (Special Administrative Region of China, SAR), Japan and mainland China, and factors that may influence their career options. It assists dental students in exploring possibilities in dentistry and preparing for their career development after graduation from dental school.

9.
Org Lett ; 23(21): 8169-8173, 2021 Nov 05.
Article in English | MEDLINE | ID: mdl-34636564

ABSTRACT

An economical and efficient protocol for the direct construction of amino skipped diynes through the Cu(I)-catalyzed reaction of enaminones and terminal alkynes has been described. Different kinds of symmetrical and asymmetrical 3-amino diynes could be obtained in up to 83% yield through a one-pot reaction under mild conditions.

10.
J Prosthodont Res ; 65(3): 298-302, 2021 Aug 21.
Article in English | MEDLINE | ID: mdl-33896888

ABSTRACT

Purpose To investigate the effects of translucency and cusp inclination on the micro-shear bond strength (µSBS) of zirconia to self-adhesive resin cement (SARC).Methods Sixty U-shaped zirconia specimens with 1.0 mm thickness consisting of three planes (0°, 20°, and 30°) simulating different cusp inclinations were fabricated from zirconia blocks of high, moderate, and low translucency (n=20). SARC was bonded to the specimen and light-cured for 40 s. The µSBS was tested using a universal testing machine with a cross-head at a speed of 0.5 mm/min and fracture mode was observed using a stereomicroscope (×50). Two-way analysis of variance followed by a post hoc Tukey's honest significant difference test was used for the statistical analyses (α=0.05).Results Varied µSBS values were found in the test groups (7.1-14.9 MPa). Within the zirconia of the same translucency, the µSBS value of the plane 0° specimen was significantly higher than that of the 20° and 30° planes (all p<0.05). Within the zirconia of the same cusp inclination, the µSBS value of highly translucent zirconia was significantly higher than that of moderate and low translucent zirconia (all p<0.05). There was no significant interaction between cusp inclination and translucency (p=0.525). Among the fracture modes, 83.33% were adhesive failure, 11.11% mixed failure, and 5.56% were cohesive failure.Conclusions Translucency and cusp inclination significantly affect the µSBS of zirconia to SARC. The higher the translucency, the greater are the µSBS values; the higher the cusp inclination, the lower are the µSBS values.


Subject(s)
Dental Bonding , Dental Stress Analysis , Materials Testing , Resin Cements , Shear Strength , Surface Properties , Zirconium
11.
Biomed Res Int ; 2021: 8875023, 2021.
Article in English | MEDLINE | ID: mdl-33575352

ABSTRACT

BACKGROUND: Monolithic restorations made of translucent yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) have become popular over the past few decades. However, whether aging affects the color and translucency of monolithic translucent Y-TZP is unclear. OBJECTIVE: The aim of this systematic review and meta-analysis of in vitro studies was to evaluate the effects of aging on the color and translucency of monolithic translucent Y-TZP ceramics. MATERIALS AND METHODS: This systematic review/meta-analysis was reported according to the PRISMA statement and registered in the OSF registries (https://osf.io/5qjmu). Four databases including Medline via the PubMed, Embase, and Web of Science databases and the Cochrane Library were searched using no publication year and language limits. The last search was executed on November 20, 2020. In vitro studies comparing the translucency and/or color of monolithic translucent Y-TZP ceramics before and after simulated aging were selected. Meta-analyses were performed using Review Manager software (version 5.3, Cochrane Collaboration, Oxford, UK) with random-effects models at a significance level of 0.05. A risk-of-bias assessment was also performed for the included studies. RESULTS: Of the 188 potentially relevant studies, 13 were included in the systematic review. The hydrothermal aging duration ranged from 1 to 100 h at relatively similar temperatures (~134°C). In the general meta-analyses, the aged Y-TZP ceramics exhibited similar translucency parameter (TP), L∗, and b∗ values compared with the nonaged controls (P = .73, P = .49, and P = .62, respectively). Moreover, there was a significant difference between the aged and nonaged Y-TZP ceramics in the a∗ value (P = .03; MD = -0.26; 95% CI = -0.51 to - 0.02), favoring the nonaged Y-TZP ceramics. The subgroup analyses showed that the duration of aging contributed to changes in the translucency and color of the Y-TZP ceramics. CONCLUSIONS: The optical properties of monolithic translucent Y-TZP ceramics were stable after hydrothermal aging at 134°C and 0.2 MPa for ≤20 h. Moreover, clinically unacceptable changes in the translucency and color of monolithic translucent Y-TZP ceramics were found after hydrothermal aging for >20 h.


Subject(s)
Ceramics , Yttrium , Zirconium , Ceramics/analysis , Ceramics/chemistry , Color , Materials Testing , Surface Properties , Temperature , Time Factors , Yttrium/analysis , Yttrium/chemistry , Zirconium/analysis , Zirconium/chemistry
12.
BMC Med Educ ; 20(1): 181, 2020 Jun 03.
Article in English | MEDLINE | ID: mdl-32493378

ABSTRACT

BACKGROUND: The aim of this study was to investigate the amount and sources of stress in dental undergraduate students in Fujian, China, and the factors associated with stress. METHODS: This cross-sectional study was conducted during the second semester of the 2017-2018 academic year at the School of Stomatology, Fujian Medical University, China. A total of 396 students were surveyed with the Dental Environment Stress Questionnaire (DES) and the Perceived Stress Scale (PSS) using an online survey system. The participants' demographic information, including sex, age, year of study, and grade point average (GPA) was also collected. One-way analysis of variance (ANOVA) was performed to compare the stress scores. Pearson correlation and multiple linear regression analyses were conducted to explore the associated factors of stress and academic performance. All statistical analyses were performed at a significance level of 5%. RESULTS: A total of 347 undergraduate students participated in the present study, for a response rate of 87.6%. There were no significant differences in the DES and PSS total scores among students of different grades and sexes. Significant differences were found in the DES "workload" and "self-efficacy beliefs" scores among students from different study years (all P < 0.05). The Multiple linear regression showed that DES and PSS scores were negatively correlated with GPA, while sex was positively correlated with GPA (all P < 0.05). Female students had significantly higher GPAs than male students. CONCLUSIONS: Dental undergraduates in Fujian, China experienced moderate levels of stress. While the amount of stress did not differ by year of study, the sources of stress did differ. Stress scores and sex were negatively correlated with academic performance.


Subject(s)
Academic Performance/psychology , Stress, Psychological/psychology , Students, Dental/psychology , Adult , China , Cross-Sectional Studies , Educational Measurement , Female , Humans , Male , Occupational Stress , Surveys and Questionnaires , Young Adult
13.
Hortic Res ; 7(1): 85, 2020.
Article in English | MEDLINE | ID: mdl-32528697

ABSTRACT

Bitter gourd (Momordica charantia) is a popular cultivated vegetable in Asian and African countries. To reveal the characteristics of the genomic structure, evolutionary trajectory, and genetic basis underlying the domestication of bitter gourd, we performed whole-genome sequencing of the cultivar Dali-11 and the wild small-fruited line TR and resequencing of 187 bitter gourd germplasms from 16 countries. The major gene clusters (Bi clusters) for the biosynthesis of cucurbitane triterpenoids, which confer a bitter taste, are highly conserved in cucumber, melon, and watermelon. Comparative analysis among cucurbit genomes revealed that the Bi cluster involved in cucurbitane triterpenoid biosynthesis is absent in bitter gourd. Phylogenetic analysis revealed that the TR group, including 21 bitter gourd germplasms, may belong to a new species or subspecies independent from M. charantia. Furthermore, we found that the remaining 166 M. charantia germplasms are geographically differentiated, and we identified 710, 412, and 290 candidate domestication genes in the South Asia, Southeast Asia, and China populations, respectively. This study provides new insights into bitter gourd genetic diversity and domestication and will facilitate the future genomics-enabled improvement of bitter gourd.

14.
Shanghai Kou Qiang Yi Xue ; 29(1): 36-39, 2020 Feb.
Article in Chinese | MEDLINE | ID: mdl-32524118

ABSTRACT

PURPOSE: To investigate the effect of ultrasonic scaling on micro-leakage of all-ceramic crowns. METHODS: 48 first premolars of the similar shape and size were collected and prepared by one attending doctor. Two groups were randomly divided (zirconia crown group and glass ceramic crown group, with 24 in each group), and each group was randomly divided into two subgroups (resin cement group and resin modified glass cement subgroup, n=6). After the crowns were bonded and solidified for 24 h, 3 samples were randomly selected from each subgroup for ultrasonic scaling for 60 s, and the other 3 samples were used as the negative control group. After all samples were soaked in 5% fuchsin solution at room temperature for 48 h, buccal and lingual incisions were made, and double-blind scoring was performed for micro-leakage at the crown edge of each sample. SPSS 17.0 software package was used for statistical analysis. RESULTS: There were significant differences between the negative group and the ultrasonic group in micro-leakage of crowns which were cemented with resin modified glass cement(P<0.05), but there was no significant difference between the negative group and the ultrasonic group in micro-leakage of crowns which were cemented with resin cement(P>0.05). When the same adhesive was used, there was significant difference in microleakage between the zirconia crown and the glass-ceramic crown, whether ultrasonic supragingival scaling was performed or not(P<0.05). CONCLUSIONS: Ultrasonic scaling had significant effect on micro-leakage of crowns which were cemented with resin modified glass cement, and but had no significant effect on micro-leakage of crowns which were cemented with resin cement.


Subject(s)
Dental Leakage , Cementation , Ceramics , Crowns , Dental Cements , Glass Ionomer Cements , Humans , Materials Testing , Resin Cements , Ultrasonics
15.
Phytother Res ; 34(3): 640-648, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31742778

ABSTRACT

Ganoderic Acid A (GAA) is often applied for healing cardiovascular and cerebrovascular ailments, but the influences in cerebral ischemia injury are still hazy. The research delved into the functions of GAA in hypoxia-triggered impairment in PC12 cells. PC12 cells received hypoxia management for 12 hr, and subsequently, cell viability, migration, apoptosis, and correlative protein levels were assessed. After preprocessing with GAA, above cell behaviors were monitored again. The vector of microRNA (miR)-153 inhibitor was utilized for PC12 cell transfection to further explore the functions of miR-153 in hypoxia-impaired cells. Pathways of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and mammalian target of rapamycin (mTOR) were investigated via executing western blot for uncovering the latent mechanism. Results revealed that hypoxia disposition triggered PC12 cells impairment via restraining cell viability and migration and accelerating apoptosis. However, GAA visibly mollified hypoxia-provoked impairment in PC12 cells. Interestingly, the enhancement of miR-153 triggered by GAA was observed in hypoxia-impaired PC12 cells. After miR-153 inhibitor transfection, the protective functions of GAA in hypoxia-impaired PC12 cells were dramatically inversed. Furthermore, GAA caused PI3K/AKT and mTOR activations via enhancement of miR-153 in hypoxia-impaired PC12 cells. The findings evinced that GAA exhibited the protective functions in PC12 cells against hypoxia-evoked impairment through activating PI3K/AKT and mTOR via elevating miR-153.


Subject(s)
Cytoprotection/drug effects , Heptanoic Acids/pharmacology , Lanosterol/analogs & derivatives , MicroRNAs/genetics , Animals , Apoptosis/drug effects , Cell Hypoxia , Cell Survival/drug effects , Lanosterol/pharmacology , Oncogene Protein v-akt/metabolism , PC12 Cells , Phosphatidylinositol 3-Kinases/metabolism , Rats , TOR Serine-Threonine Kinases/metabolism
16.
Biomed Res Int ; 2019: 7404038, 2019.
Article in English | MEDLINE | ID: mdl-31240222

ABSTRACT

The aim of the present study was to evaluate the in vitro cytotoxicity of self-adhesive dual-cured resin cement (SADRC) polymerized beneath three different cusp inclinations of zirconia with different light curing time. A commercial SADRC (Multilink Speed) was polymerized beneath zirconia (ZrO2) with three different cusp inclinations (0°, 20°, and 30°) for 20 s or 40 s. After being stored in light-proof box for 24 h, the ZrO2-SADRC specimens were immersed in DMEM for 72 h and then we got the extract solution, cultured the human gingival fibroblasts (HGF, 8 × 103 per well) with 100% or 50% concentrations of the extract solution for 24 h, 72 h, and 120 h, respectively, and evaluated cytotoxicity of the polymerized SADRC with CCK-8 assay in optical density (OD) values, relative growth rates (RGR), and cytotoxicity grades. Statistical analysis was conducted using a two-way ANOVA followed by post hoc Student-Newman-Keuls test. The OD values varied from 0.8930 to 3.2920, the RGR varied from 33.93% to 98.68%, and the cytotoxicity grades varied from 0 to 2. There was significant difference in the OD values among the different cusp inclinations of zirconia (P < 0.001), and there was significant difference in the OD values between the different light curing times in some situations (P < 0.05). The cusp inclination of zirconia affects the in vitro cytotoxicity of SADRC. Prolonging the light curing time from 20 s to 40 s can reduce the in vitro cytotoxicity of SADRC when the cusp inclination of zirconia is smaller than 20°.


Subject(s)
Adhesives/toxicity , Polymerization , Resin Cements/toxicity , Zirconium/chemistry , Adhesives/chemistry , Cell Culture Techniques , Cell Line , Computer-Aided Design , Curing Lights, Dental , Dental Bonding , Fibroblasts , Humans , In Vitro Techniques , Light-Curing of Dental Adhesives , Materials Testing , Resin Cements/chemistry , Surface Properties , Time Factors
17.
Chem Asian J ; 14(11): 1941-1944, 2019 Jun 03.
Article in English | MEDLINE | ID: mdl-30931538

ABSTRACT

Ynones are useful substrates for transition-metal-mediated synthesis. The AuI -catalyzed 1,3-O-transposition is an important reaction of ynones. Recently, an efficient CuI -catalyzed synthesis of trisubstituted Z-enol esters via interrupting the traditional 1,3-O-transposition reaction of ynones was reported by Zhu's group. Herein, density functional theory studies disclosed that the hydrogen bond formed by carboxylic acid plays an important role for the reactivity and selectivity in this novel reaction. A qualitative rule was also found to explain the substituent effect in the ynone substrate, and this is consistent with experiments. The AuI -catalyst and CuI -catalyst were further compared to interpret the essential cause of why the AuI -catalyst prefers the 1,3-O-transpostion reaction. These conclusions might be helpful for the rational design of reactions of ynones.

18.
J Adhes Dent ; 20(2): 107-112, 2018.
Article in English | MEDLINE | ID: mdl-29922752

ABSTRACT

PURPOSE: To evaluate the effect of cusp inclination and light-curing time on the microshear bond strength (µSBS) between zirconia and a dual-cure self-adhesive composite cement and zirconia. MATERIALS AND METHODS: Forty U-shaped specimens with angled surfaces, simulating different cusp inclinations (0 degrees, 20 degrees, and 30 degrees), were fabricated from zirconia blocks (Zenostar, Wieland). The specimens were randomly divided into two groups (n = 20) according to different light-curing times of the adhesive composite cements (20 s and 40 s). Three polyethylene tubes filled with a dual-curing self-adhesive composite cement (Multilink Speed, Ivoclar Vivadent) were bonded to the surfaces of each specimen with light-curing times of 20 s and 40 s. The µSBS was tested using a universal testing machine with a crosshead speed of 0.5 mm/min. Failure analysis was performed. Two-way ANOVA (cusp inclination and light-curing time) followed by two independent samples t-test were used for statistical analyses (α = 0.05). RESULTS: The composite cement showed various bond strengths to angled zirconia surfaces (7.07 ± 1.69 to 13.91 ± 3.11 MPa). The µSBS between composite cement and 0-degree zirconia surfaces was statistically higher than that of 20- and 30-degree zirconia surfaces. The composite cement light cured for 40 s showed nonsignificantly higher µSBS than did the composite cement cured for 20 s. Adhesive failure was the most common failure mode. CONCLUSIONS: Cusp inclination affected bond strength between the dual-curing self-adhesive composite cement and zirconia.


Subject(s)
Curing Lights, Dental , Dental Bonding , Composite Resins , Materials Testing , Random Allocation , Resin Cements , Surface Properties , Zirconium
19.
J Esthet Restor Dent ; 30(2): E52-E60, 2018 03.
Article in English | MEDLINE | ID: mdl-29247591

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate the influence of study protocols on the effects of bleaching on the surface roughness, substance loss, flexural strength (FS), flexural modulus (FM), Weibull parameters, and color of 7 restorative materials. MATERIALS AND METHODS: The test materials included 4 composite resins, 1 glass-ionomer cement, 1 dental ceramic, and 1 polyacid-modified composite. The specimens were randomly divided into 4 groups (n = 20) according to different study protocols: a bleaching group at 25°C (group 25B), a bleaching group at 37°C (group 37B), a control group at 25°C (group 25C), and a control group at 37°C (group 37C). The specimens in the bleaching group were treated with 40% hydrogen peroxide for 80 min at the respective environmental temperatures. The surface roughness, substance loss, FS, FM, and color of the specimens were measured before and after treatment. FS data were also subjected to Weibull analysis, which was used to estimate of the Weibull modulus (m) and the characteristic strength (σ0 ). RESULTS: Surface roughness increased and significant color changes were observed for all tested specimens after bleaching treatment, except for the ceramic. After bleaching at 37°C, the polyacid-modified composite showed significantly reduced FS, FM, m, and σ0 values in comparison to the control specimens stored at 37°C in whole saliva. Significant differences were also found between the 37B and 25B polyacid-modified composite groups in terms of surface roughness, FS, m, σ0 , and color changes. CONCLUSIONS: Varying effects of bleaching on the physical properties of dental restorative materials were observed, and the influences of the study protocols on bleaching effects were found to be material-dependent. CLINICAL SIGNIFICANCE: The influence of study protocols on the effects of bleaching on the surface roughness, flexural properties, and color of dental restorative materials are material-dependent and should be considered when evaluating the effects of bleaching on dental restorative materials.


Subject(s)
Hydrogen Peroxide , Tooth Bleaching , Carbamide Peroxide , Compomers , Composite Resins , Dental Restoration, Permanent , Glass Ionomer Cements , Materials Testing , Peroxides , Surface Properties , Urea
20.
J Sci Food Agric ; 98(7): 2681-2688, 2018 May.
Article in English | MEDLINE | ID: mdl-29077199

ABSTRACT

BACKGROUND: The elemental uptake and allocation patterns of crops create insight for nutrient management. Two-year field experiments were conducted to determine the growth and nitrogen (N) uptake patterns of bitter gourd and to evaluate different N management strategies. Two N practices during the nursery stage, namely the conventional fertilizer method (Scon) and the controlled-release fertilizer management method (Scrf), combined with three N management strategies after transplanting, namely zero N fertilizer application (Nno), the conventional strategy (Ncon) and the systematic N management strategy (Nopt), were assessed. RESULTS: Averaged over two years, the Scrf-Nopt treatment performed best, producing 33.1 t ha-1 fruit yield with 310 kg N ha-1 , indicating that the yield was 22.6% greater by using 18.8% less fertilizer N than in the Scon-Ncon treatment. The Scrf-Nopt treatment facilitated plant growth by accumulating 20.0% more total dry weight and prioritized its allocation to productive organs (57.2%), while the Scon-Ncon strategy was biased toward leaves (56.3%) over fruits (43.8%). Nitrogen uptake and distribution closely followed the pattern of biomass. CONCLUSION: The Scrf-Nopt fertilization strategy coordinated the important role that N plays in total accumulation and well proportion of biomass and N in bitter gourd developmental processes. © 2017 Society of Chemical Industry.


Subject(s)
Crop Production/methods , Fertilizers/analysis , Momordica charantia/growth & development , Momordica charantia/metabolism , Nitrogen/metabolism , Biomass , Momordica charantia/chemistry , Nitrogen/analysis
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