[Influence of Land Use Structure and Spatial Pattern on Water Quality of Small and Medium-sized Rivers in Poyang Lake Basin].

To reveal the influence mechanism of land use structure and spatial pattern on water quality of small and medium-sized rivers, water samples were collected from 25 sampling points in three small and medium-sized rivers of the Poyang Lake Basin in January 2022 and July 2022. Bioenv analysis, the Mantel test, and variance partitioning analysis were used to quantify the effects of land use structure and spatial patterns on water quality at different spatial scales; generalized additive models were used to fit the relationship between water quality and different land use structures and spatial patterns; and a generalized linear model was used to construct segmented regression models and calculate the thresholds based on the stepwise recursive method. The results showed that:① the average interpretation rate of land use structure and spatial pattern on river water quality was 59.72% during the wet period and 48.95% during the dry period. The sub-basin and riparian 100 m scales were the key scales of land use structure and spatial pattern affecting water quality in small and medium-sized rivers, with an average explanation rate of 54.70% and 64.88%, respectively. The joint explanation of land use structure and spatial pattern was an important factor driving the change in river water quality, accounting for 66.90% of the total explanation. ② The impact of land use structure on the water quality of small and medium-sized rivers had a significant threshold effect. When the proportion of construction land was less than 2%, farmland was less than 8%, or forest land was more than 82% at the sub-basin scale and the proportion of construction land was less than 12%, farmland was less than 41%, or forest land was more than 49% at the riparian buffer scale, all could significantly improve water quality. ③ The effect of spatial pattern on water quality in small and medium-sized rivers also had a threshold effect but was weaker than that of land use structure. A patch shape value more than 28.77 or patch diversity more than 0.69 at the sub-basin scale and a patch shape value more than 2.99 or patch diversity more than 1.02 at the riparian buffer scale could improve water quality. The above results showed that strengthening the management of land use at the sub-basin and riparian 100 m scales and setting a reasonable threshold of land use structure and spatial pattern can effectively prevent water quality from deteriorating.

The biomechanical role of periodontal ligament in bonded and replanted vertically fractured teeth under cyclic biting forces / 国际口腔科学杂志·英文版

After teeth are replanted, there are two possible healing responses: periodontal ligament healing or ankylosis with subsequent replacement resorption. The purpose of this study was to compare the fatigue resistance of vertically fractured teeth after bonding the fragments under conditions simulating both healing modes. Thirty-two human premolars were vertically fractured and the fragments were bonded together with Super-Bond C&B. They were then randomly distributed into four groups (BP, CP, CA, BA). The BP and CP groups were used to investigate the periodontal ligament healing mode whilst the BA and CA groups simulated ankylosis. All teeth had root canal treatment performed. Metal crowns were constructed for the CP and CA groups. The BP and BA groups only had composite resin restorations in the access cavities. All specimens were subjected to a 260 N load at 4 Hz until failure of the bond or until 2 × 10⁶ cycles had been reached if no fracture occurred. Cracks were detected by stereomicroscope imaging and also assessed via dye penetration tests. Finally, interfaces of the resin luting agent were examined by scanning electron microscope. The results confirmed that the fatigue resistance was higher in the groups with simulated periodontal ligament healing. Periodontal reattachment showed important biomechanical role in bonded and replanted vertically fractured teeth.

Genomewide variation in an introgression line of rice-Zizania revealed by whole-genome re-sequencing.

BACKGROUND: Hybridization between genetically diverged organisms is known as an important avenue that drives plant genome evolution. The possible outcomes of hybridization would be the occurrences of genetic instabilities in the resultant hybrids. It remained under-investigated however whether pollination by alien pollens of a closely related but sexually "incompatible" species could evoke genomic changes and to what extent it may result in phenotypic novelties in the derived progenies. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we have re-sequenced the genomes of Oryza sativa ssp. japonica cv. Matsumae and one of its derived introgressant RZ35 that was obtained from an introgressive hybridization between Matsumae and Zizanialatifolia Griseb. in general, 131 millions 90 base pair (bp) paired-end reads were generated which covered 13.2 and 21.9 folds of the Matsumae and RZ35 genomes, respectively. Relative to Matsumae, a total of 41,724 homozygous single nucleotide polymorphisms (SNPs) and 17,839 homozygous insertions/deletions (indels) were identified in RZ35, of which 3,797 SNPs were nonsynonymous mutations. Furthermore, rampant mobilization of transposable elements (TEs) was found in the RZ35 genome. The results of pathogen inoculation revealed that RZ35 exhibited enhanced resistance to blast relative to Matsumae. Notably, one nonsynonymous mutation was found in the known blast resistance gene Pid3/Pi25 and real-time quantitative (q) RT-PCR analysis revealed constitutive up-regulation of its expression, suggesting both altered function and expression of Pid3/Pi25 may be responsible for the enhanced resistance to rice blast by RZ35. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that introgressive hybridization by Zizania has provoked genomewide, extensive genomic changes in the rice genome, and some of which have resulted in important phenotypic novelties. These findings suggest that introgressive hybridization by alien pollens of even a sexually incompatible species may represent a potent means to generate novel genetic diversities, and which may have played relevant roles in plant evolution and can be manipulated for crop improvements.

Effect of curing modes on knoop hardness and microtensile bond strength of two dentin adhesives / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluated the effect of curing modes and light-cure times on knoop hardness (KH) and microtensile bond strength (µTBS) of dentin adhesives in vitro.</p><p><b>METHODS</b>Twenty molars were made into 80 dentin slices (about 1 mm thick). The dentin slices were prepared with an etch&rinse adhesive A (ONE-STEP PLUS) and a self-etch adhesive B (Clearfil SE Bond), and light-cured respectively under fast mode, i.e.1250 mW/cm(2) light intensity for 10 s, 15 s, 20 s, and ramp mode (soft start curing mode), i.e.initial 0 mW/cm(2) gradually increasing to 1250 mW/cm(2) in first 10 s, then steady for the next 10 s. The prepared dentin slices were kept in dark dry room for 24 h at 37°C, and KH were tested. The other 40 molars were flattened to expose coronal dentin, prepared with adhesives as above. Then the prepared teeth were restored with resin composites incrementally and cured under fast mode. The restored teeth were stored in water for 24 h at 37°C, and slowly sectioned to obtain multiple bonded beams. After 7 d water-storage, the samples received microtensile bond test, and the failure models of beams were observed under a stereomicroscope. Data were analyzed by ANOVA and LSD test (α = 0.05).</p><p><b>RESULTS</b>No statistical difference in KH [(28.20 ± 5.36), (29.13 ± 5.60), (28.13 ± 4.40), (27.06 ± 3.77) MPa] and µTBS [(22.30 ± 5.07), (22.73 ± 6.59), (26.32 ± 6.17), (25.67 ± 4.31) MPa] of adhesive A were found between four curing conditions (fast mode for 10 s, 15 s, 20 s and ramp mode for 20 s) (P > 0.05). In adhesive B, KH of Fast 20 s [(28.23 ± 3.67) MPa] were significantly higher than those of Fast 10 s [(14.15 ± 2.24) MPa] and Fast 15 s [(17.63 ± 2.17) MPa] (P < 0.05). The µTBS of Fast 20 s [(42.52 ± 3.59) MPa] were significantly higher than those of Fast 10 s [(24.21 ± 3.60) MPa], Fast 15 s [(22.25 ± 4.16) MPa] and Ramp 20 s [(31.12 ± 5.40) MPa] (P < 0.05). In Fast 20 s and Ramp 20 s modes, there were no statistical difference in KH of adhesive A and B, while µTBS of adhesive B were higher than that of adhesive A(P < 0.05).</p><p><b>CONCLUSIONS</b>As for different type dentin adhesives, the appropriate curing time in fast mode is different, and ramp mode (soft start curing mode) has no advantage over fast mode.</p>