[Effects of seed grading on population regularity degree and yield of summer maize]

Grading seeds based on grain size is an effective measure to improve population regularity degree and increase the yield of summer maize. Taking Denghai 605 as the experimental material, we set up a field experiment with treatments based on grain size: large seeds (L), medium-round seeds (MR), medium-flat seeds (MF), medium-round and medium-flat mixed seeds (MRF), and small seeds (S), with no-grading seeds as control (CK). We investigated seedling emergence rate, population regularity degree (including height, ear height and stem diameter), seedling sturdiness index, photosynthetic characteristics, dry matter accumulation and distribution characteristics, and yield. The results showed that the emergence rate followed an order of L>MR>MRF>MF>CK>S, with that of L treatment differed little from MR, MF and MRF treatments, but being significantly higher than S and CK treatments. Plant height and stem diameter population regularity degree of MRF treatment before seven-leaf stage was not different from those of L, MR, MF and S treatments, but significantly higher than those of CK. At the tasseling stage, all treatments had higher population regularity degree of plant height than other stages. Ear height population regularity degree of L, MR, MF, MRF, and S increased by 11.1%, 10.3%, 9.5%, 7.1%, and 6.4% compared with CK, respectively. The seedling sturdiness index of MRF treatment increased by 36.7% compared with S treatment, but was not significantly different from L treatment. The leaf area index of the L and MRF treatments was significantly higher than that of CK, and both had higher population photosynthetic properties. The population dry matter accumulation showed a pattern as L>MR>MRF>MF>CK>S. There was no significant difference among L, MR, and MRF treatments, but that in L being obviously higher than MF, CK, and S treatments. After seed grading, the number of harvested ears of the L and MRF treatments increased significantly, and the yield were shown as L>MR>MRF>MF>CK>S. There was no difference between the yield of MRF, MR and MF treatments. In conclusion, the performance of L treatment was improved but the number was small. Considering the grading cost and yield, the MRF treatment can save the seed amounts of sowing, realize mechanized sowing and precision sowing.

[Safety analysis of cesarean myomectomy in twin pregnancies with intramural myomas]

Objective: To estimate the safety of myomectomy in twin pregnant women with intramural myomas during cesarean section. Methods: The clinical data of 145 cases of twin pregnancies with intramural myomas who were delivered by cesarean section in Beijing Obstetrics and Gynecology Hospital, Capital Medical University from June 2013 to December 2021 were collected. Maternal demographics, fibroids' characteristics, maternal and fetal outcomes were compared between groups of cesarean section with myomectomy (myomectomy group, 49 cases) and cesarean section only (non-myomectomy group, 96 cases). Results: Compared with non-myomectomy group, myomectomy group had significantly prolonged operative time [50.0 minutes (37.5-57.5 minutes) vs 40.0 minutes (35.0-50.0 minutes), respectively; P=0.007] and significantly longer postoperative hospital stay [4.0 days (3.0-4.0 days) vs 3.0 days (3.0-4.0 days), respectively; P=0.047). Other maternal and fetal outcomes such as estimated blood loss, hemoglobin difference, postpartum hemorrhage, blood transfusion, B-Lynch structure, uterine artery ligation, postoperative fever and neonatal Apgar score showed no significant differences (all P>0.05). For intramural myomas <5 cm, there were no significant differences in maternal and fetal outcomes between myomectomy group and non-myomectomy group (all P>0.05). For intramural myomas ≥5 cm, operative time [55.0 minutes (40.0-60.0 minutes) vs 42.5 minutes (40.0-50.0 minutes), respectively; P=0.019] was significantly prolonged, postoperative hospital stay [4.0 days (4.0-5.0 days) vs 4.0 days (3.0-4.0 days), respectively; P=0.048] was significantly longer in myomectomy group than non-myomectomy group, but there were no significant differences in other maternal and fetal outcomes (all P>0.05). Conclusion: For twin pregnancies with intramural myomas, it is safe and feasible to remove intramural myomas during cesarean section by experienced obstetricians.

Preventing arteriovenous shunt failure in hemodialysis patients: a population-based cohort study

Essentials Uncertainty remains about antiplatelets for vascular access patency in hemodialysis patients. 95 971 people under hemodialysis were followed in a claims database in Taiwan. Aspirin reduced vascular access failure rate and did not increase major bleeding rate. Clopidogrel, Aggrenox, and warfarin might increase major bleeding rate. SUMMARY: Background Dialysis adequacy is a major determinant of survival for patients with end-stage renal disease. Good vascular access is essential to achieve adequate dialysis. Objectives This study evaluated the impacts of different drugs on the vascular access failure rate of an arteriovenous fistula or an arteriovenous graft and the rate of major bleeding in hemodialysis patients. Patients and methods We studied patients with end-stage renal disease registered in the Taiwan National Health Insurance program from 1 January 1997 to 31 December 2012. A total of 95 971 patients were enrolled in our study. Vascular access dysfunction was defined as the need for thrombectomy or percutaneous angioplasty. Major bleeding was defined as emergency department visits or hospitalization with a primary diagnosis of gastrointestinal bleeding or intracerebral hemorrhage. The adjusted odds ratios between person-quarters with or without antiplatelet or oral anticoagulant use were calculated using a generalized estimating equation. Results The odds ratio of vascular access failure was 0.21 (0.11-0.39) for aspirin, 0.76 (0.74-0.79) for clopidogrel, 0.67 (0.59-0.77) for dipyridamole, 0.67 (0.53-0.86) for Aggrenox and 0.96 (0.90-1.03) for warfarin. The highest odds ratio for intracerebral hemorrhage was 5.33 (1.25-22.72) in younger patients using Aggrenox. The highest odds ratio for gastrointestinal bleeding was 1.34 (1.10-1.64) for clopidogrel. Conclusion Antiplatelet agents, but not warfarin, might reduce the vascular access thrombosis rate. The gastrointestinal bleeding rate was increased in the group using clopidogrel. Aggrenox should be used with caution in young individuals because it might increase the rate of intracerebral hemorrhage.

Ultrafast Dynamics Evidence of High Temperature Superconductivity in Single Unit Cell FeSe on SrTiO_{3}

We report the time-resolved excited state ultrafast dynamics of single unit cell (1 UC) thick FeSe films on SrTiO_{3} (STO), with FeTe capping layers. By measuring the photoexcited quasiparticles' density and lifetime, we unambiguously identify a superconducting (SC) phase transition, with a transition temperature T_{c} of 68 (-5/+2)  K and a SC gap of Δ(0)=20.2±1.5  meV. The obtained electron-phonon coupling strength λ is as large as 0.48, demonstrating the likely crucial role of electron-phonon coupling in the high temperature superconductivity of the 1 UC FeSe on STO systems. We further find a 0.05 THz coherent acoustic phonon branch in the capping layer, which provides an additional decay channel to the gluing bosons.

Cyclophilin A and nuclear factor of activated T cells are essential in cyclosporine-mediated suppression of polyomavirus BK replication

Immunosuppressants have impacts on the development of polyomavirus-associated nephropathy. We previously demonstrated that cyclosporin A (CsA) suppressed polyomavirus BK (BKV) replication. The role of cyclophilin A (CypA) and nuclear factor of activated T cells (NFAT) in CsA-imposed suppression of BKV replication was determined in this study. Results demonstrated that knockdown of CypA but not CypB significantly reduced BKV large T antigen (TAg) expression and BKV titer. Overexpression of CypA reversed CypA siRNA-induced inhibition in BKV TAg expression. In addition, CypA overexpression attenuated the suppressive effect of CsA on TAg expression, suggesting CypA implicated in CsA-mediated anti-BKV effect. Knockdown of NFATc3 abrogated TAg expression, while overexpression of NFATc3 promoted TAg expression and augmented BKV promoter activity. NFATc3 binding to the BKV promoter was verified by chromatin immunoprecipitation assay and electrophoretic mobility shift assay. Renal histology also displayed an increase in NFATc3 expression in tubulointerstitium of BKV-associated nephropathy. Furthermore, overexpression of NFATc3 rescued CsA-mediated inhibition of BKV load and TAg expression. A CsA analog, NIM811, which cannot block NFAT functionality, failed to suppress TAg expression. In conclusion, CypA and NFAT are indispensable in BKV replication. CsA inhibits BKV replication through CypA and NFAT, which may be potential targets of anti-BKV treatment.

Ultrasmall silver nanopores fabricated by femtosecond laser pulses

Ultrasmall nanopores in silver thin films with a diameter of about 2 nm have been fabricated using femtosecond laser ablation in liquid. Ultrafast laser pulse ablation generates highly nonequilibrium excitated states, from which silver thin films emerge and progressively grow with the assistance of capping agent molecules. During this growth process, capping agent molecules are enclaved within the film, leaving individual ultrasmall pores in the thin film. Our first-principles calculations show that the pore size is critically determined by the dimension of the confined molecules. Our approach advances the capability of optical methods in making nanoscale structures with potential applications in areas such as near-field aperture probes, imaging masks, magnetic plasmonic resonances, and biosensing with individual nanopores.

Extreme ultraviolet narrow band emission from electron cyclotron resonance plasmas

Extreme ultraviolet lithography (EUVL) is considered as the most promising solution at and below dynamic random access memory 32 nm half pitch among the next generation lithography, and EUV light sources with high output power and sufficient lifetime are crucial for the realization of EUVL. However, there is no EUV light source completely meeting the requirements for the commercial application in lithography yet. Therefore, ECR plasma is proposed as a novel concept EUV light source. In order to investigate the feasibility of ECR plasma as a EUV light source, the narrow band EUV power around 13.5 nm emitted by two highly charged ECR ion sources -- LECR2M and SECRAL -- was measured with a calibrated EUV power measurement tool. Since the emission lines around 13.5 nm can be attributed to the 4d-5p transitions of Xe XI or the 4d-4f unresolved transition array of Sn VIII-XIII, xenon plasma was investigated. The dependence of the EUV throughput and the corresponding conversion efficiency on the parameters of the ion source, such as the rf power and the magnetic confinement configurations, were preliminarily studied.

[Studies on transgenic tobacco plants expressing two kinds of insect resistant genes]

A synthetic Bt cry1Ac gene fussed with a secretary signal coding sequences at 5' end and a modified gna gene were used to construct a plant expression vector pBSGS1M+ and this vector was transferred into tobacco (Nicotiana tabacum L.) by Agrobacterium-mediated transformation method. Results of PCR, Southern blot and Slot blot analysis indicated that both the chimeric Bt cry1Ac and gna genes were integrated into the genomes of transformed plants. Western blot analysis indicated that at least the cry1Ac protein was produced in transgenic plants. Upon insect bioassay using cotton bollworm (Heliothis armigera Hubner), the mortality of insect larvae on 60% regenerated plants reached 100% in 5 days post infestation and the growth of the survived larvae was seriously inhibited; The results from insect bioassay with peach aphid (Myzus persicae) showed that the transgenic plants were aphid-resistant, evidenced by a 50%-60% reduction in aphid population density, even over 80% for some individual transgenic plants. These results reflect that the modification of the two insect resistant genes and construction of the expression vector are correct and could be valuable for later application in crop breeding for insect resistance.

[Cloning of AHA gene from Amaranthus hypochondriacus and it's aphid inhibitory effect in transgenic tabacco plants]

Using total DNA isolated from Amaranthus hypochondriacus as template, Amaranthus hypochondriacus agglutinin AHA gene was amplified by PCR and cloned. Sequence analysis results showed that this gene is consisted of 2453 base pairs including one 1538 bp intron and two exons of 212 bp and 703 bp respectively. After inverse PCR amplification, coding region of AHA gene was obtained. AHA gene with it's intron (AHAg) and withou intron (AHAc) were inserted downstream of 35S promotor in the binary vector pBin438 resulting in the construction of two plant expression vectors pBAHAg and pBAHAc repectively. Leave explants of Nicotinana tabacum var. SR1 were transformed with A. tumefaciens LBA4404 harbouring the above expression vectors. Results from PCR and Southern blot analysis showed that AHA genes were inserted into the genome of transformed tobacco plants. Immunodot blot analysis indicated that AHA was expressed in transgenic plants. The results from insect bioassay with peach aphid (Mizus persicae) showed that the transgenic plants of pBAHAg and pBAHAc were aphid resistant, evidenced by a 57%-48% reduction in insect population density, some plants were more than 85%. The aphid resistance of transgenic plants transformed with AHAg gene as judged by aphid inhibition rate was higher than that of plants transormed with AHAc gene indicating that the intron in AHAg may be favorable for expression of AHA in transgenic plants.

[Studies on transgenic oilseed rape (Brassica napus) plants transformed with beta-1,3-glucanase and chitinase genes and its resistance to Sclerotinia sclerotiorium]

By Agrobacterium-mediated method, the cotyledonary petiole of good quality rape variety H165 was transformed with plant expression vector pBLGC which constitutively express beta-1,3-glucanase and chitinase genes. We obtained some Kanamycin(Kan)-resistant regenerational green shoots, with these shoots, PCR identification was conducted. Results showed that 30% green shoots which grew in medium of Kan 15 mg/L and 53% green shoots in Kan 25 mg/L had positive reaction. We also made dot blot analysis with those green shoots, some of them gave positive signal, indicating that the foreign genes had integrated into rape genome. Fungal challenge of these transgenic plants showed that some plants were much more resistant to Sclerotinia sclerotiorium than non-transgenic control plants.

[Studies of transgenic tobacco plants expressing beta-1,3-glucanase and chitinase genes and their potential for fungal resistance]

Plant bivalent expression vector pBLGC for basic tobacco beta-1, 3-glucanase and bean chitinase genes were constructed, and the tobacco tissue was transformed. Transgenic tobacco plants were carried out for analysis by PCR, PCR-Southern blot, Dot blot, Western blot, etc., and the results showed that some transgenic plants gave strong positive signal, it suggested that foreign genes have been integrated into tobacco genome, and expressed correctly. Fungal challenge with Alternaria alternata showed that transgenic plants were much more resistant to this pathogenic fungus.

Insect resistance of transgenic tobacco plants expressing delta-endotoxin gene of Bacillus thuringiensis

The initiative B.thuringiensis delta-endotoxin (Bt toxin) gene clones TH12 and TH48 contain two different classes of homologous genes, the 5.3 kb class and 6.6 kb class, respectively. Bt toxin genes of both classes, modified at the 5'-end and truncated at the 3'-end, can still be expressed to produce the insecticidal, truncated toxin proteins in E. coli. The modified Bt toxin genes were inserted into the plant binary expression vector pBin 437 (a derivative plasmid of pBin 19) and were transferred into tobacco by Ti plasmid-mediated gene transfer system. Southern blot and DNA slot blot analysis indicate that the Bt toxin genes have been integrated into tobacco genome at a copy number of 1 to 5. Northern blot analysis of polyA+ RNAs from progeny of the transgenic plants revealed that Bt toxin genes of both 5.3 kb and 6.6 kb classes were expressed in transgenic plants, though the transcripts were degraded to RNAs of lower molecular weights. In insecticidal test, 5 plants from the progeny of 5.3 kb class gene-transformed SR1 tobacco plants and 3 plants from those of 6.6 kb class gene-transformed plants were found to be toxic to the testing larvea of H.assulta. In comparison with the control, mortality of the insects fed on transgenic plants reached 40-50% and the growth of the survived insects was remarkably inhibited. These results indicate that the modified Bt genes of the 5.3 kb and 6.6 kb classes were expressed in transgenic plants and could confer on the transgenic plants a new character of insect resistance.

Cleavage of a viral polyprotein by a cellular proteolytic activity

The 200,000-dalton polyprotein encoded by the bottom component RNA of cowpea mosaic virus was synthesized in rabbit reticulocyte lysates, and this in vitro-synthesized protein was isolated from the lysate reaction mixture by sucrose density gradient centrifugation. Incubation of the isolated polyprotein with buffer caused no change in the protein, but incubation with reticulocyte lysates or with fractionated lysate proteins resulted in cleavage of the protein into the expected cleavage products (32,000- and 170,000-dalton proteins). This finding indicated that reticulocytes contain a proteolytic activity that is needed for the primary cleavage reaction. A cleavage assay in which we used partially purified preparations showed that cleavage was an ATP-dependent reaction.

Study on the genome of cauliflower mosaic virus (Xinjiang isolate). Restriction mapping of virion and cloned viral DNA

The genomic DNA of CaMV (Xinjiang isolate) was mapped on the virion DNA with a number of restriction endonucleases by double digestions and partial digestions of one-end 32P-labelled fragments. It contained the unique sites of BglI, SalI and XhoI. BamHI and HhaI each cut it at two sites, EcoRI at five sites (three of which were located), HpaII at seven sites, BglII at eight sites, and HaeIII at ten sites. The sites of all the enzymes used above, as well as HindIII which cut at ten sites were also mapped on the cloned CaMV DNA. Virion DNA and cloned viral DNA gave the same results in the number and location of cleavage sites of the restriction enzymes tested on both DNAs. Like most of the other isolates, CaMV-Xinjiang isolate has three single-stranded discontinuities. From the digestion patterns of SalI, XhoI, EcoRI and HhaI, it is concluded that the restriction map of CaMV-XJ genome is closely related to that of BKMV isolate from East Germany.