Electrochemical mechanical micromachining based on confined etchant layer technique

National Science Foundation of China [91023006, 91023047, 91023043, 21061120456, 21021002]; Natural Science Foundation of Fujian Province of China [2012J06004]; Fundamental Research Funds for the Central Universities [2010121022]; Scientific Research Foundation for the Returned Overseas Chinese Scholars (State Education Ministry)The confined etchant layer technique (CELT) has been proved an effective electrochemical microfabrication method since its first publication at Faraday Discussions in 1992. Recently, we have developed CELT as an electrochemical mechanical micromachining (ECMM) method by replacing the cutting tool used in conventional mechanical machining with an electrode, which can perform lathing, planing and polishing. Through the coupling between the electrochemically induced chemical etching processes and mechanical motion, ECMM can also obtain a regular surface in one step. Taking advantage of CELT, machining tolerance and surface roughness can reach micro-or nano-meter scale

The Genomes of Oryza sativa: A History of Duplications

We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000–40,000. Only 2%–3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family

SN 2021csp -- the explosion of a stripped envelope star within a H and He-poor circumstellar medium

We present observations of SN 2021csp, a unique supernova (SN) which displays evidence for interaction with H- and He- poor circumstellar material (CSM) at early times. Using high-cadence spectroscopy taken over the first week after explosion, we show that the spectra of SN 2021csp are dominated by C III lines with a velocity of 1800 km s$^{-1}$. We associate this emission with CSM lost by the progenitor prior to explosion. Subsequently, the SN displays narrow He lines before metamorphosing into a broad-lined Type Ic SN. We model the bolometric light curve of SN 2021csp, and show that it is consistent with the energetic ($4\times10^{51}$ erg) explosion of a stripped star, producing 0.4 M$_\odot$ of 56Ni within a $\sim$1 M$_\odot$ shell of CSM extending out to 400 R$_\odot$...

Orbit correction based on improved reinforcement learning algorithm

Recently, reinforcement learning (RL) algorithms have been applied to a wide range of control problems in accelerator commissioning. In order to achieve efficient and fast control, these algorithms need to be highly efficient, so as to minimize the online training time. In this paper, we incorporated the beam position monitor trend into the observation space of the twin delayed deep deterministic policy gradient (TD3) algorithm and trained two different structure agents, one based on physical prior knowledge and the other using the original TD3 network architecture. Both of the agents exhibit strong robustness in the simulated environment. The effectiveness of the agent based on physical prior knowledge has been validated in a real accelerator. Results show that the agent can overcome the difference between simulated and real accelerator environments. Once the training is completed in the simulated environment, the agent can be directly applied to the real accelerator without any online training process. The RL agent is deployed to the medium energy beam transport section of China Accelerator Facility for Superheavy Elements. Fast and automatic orbit correction is being tested with up to ten degrees of freedom. The experimental results show that the agents can correct the orbit to within 1 mm. Moreover, due to the strong robustness of the agent, when a trained agent is applied to different lattices of different particles, the orbit correction can still be completed. Since there are no online data collection and training processes, all online corrections are done within 30 s. This paper shows that, as long as the robustness of the RL algorithm is sufficient, the offline learning agents can be directly applied to online correction, which will greatly improve the efficiency of orbit correction. Such an approach to RL may find promising applications in other areas of accelerator commissioning

Transcriptome Analysis Reveals a Comprehensive Virus Resistance Response Mechanism in Pecan Infected by a Novel Badnavirus Pecan Virus

Pecan leaf-variegated plant, which was infected with a novel badnavirus named pecan mosaic virus (PMV) detected by small RNA deep sequencing, is a vital model plant for studying the molecular mechanism of retaining green or chlorosis of virus-infected leaves. In this report, PMV infection in pecan leaves induced PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI). PMV infection suppressed the expressions of key genes of fatty acid, oleic acid (C18:1), and very-long-chain fatty acids (VLCFA) biosynthesis, indicating that fatty acids-derived signaling was one of the important defense pathways in response to PMV infection in pecan. PMV infection in pecans enhanced the expressions of pathogenesis-related protein 1 (PR1). However, the transcripts of phenylalanine ammonia-lyase (PAL) and isochorismate synthase (ICS) were downregulated, indicating that salicylic acid (SA) biosynthesis was blocked in pecan infected with PMV. Meanwhile, disruption of auxin signaling affected the activation of the jasmonic acid (JA) pathway. Thus, C18:1 and JA signals are involved in response to PMV infection in pecan. In PMV-infected yellow leaves, damaged chloroplast structure and activation of mitogen-activated protein kinase 3 (MPK3) inhibited photosynthesis. Cytokinin and SA biosynthesis was blocked, leading to plants losing immune responses and systemic acquired resistance (SAR). The repression of photosynthesis and the induction of sink metabolism in the infected tissue led to dramatic changes in carbohydrate partitioning. On the contrary, the green leaves of PMV infection in pecan plants had whole cell tissue structure and chloroplast clustering, establishing a strong antiviral immunity system. Cytokinin biosynthesis and signaling transductions were remarkably strengthened, activating plant immune responses. Meanwhile, cytokinin accumulation in green leaves induced partial SA biosynthesis and gained comparatively higher SAR compared to that of yellow leaves. Disturbance of the ribosome biogenesis might enhance the resistance to PMV infection in pecan and lead to leaves staying green

Risk factors for urinary tract infection in patients with urolithiasis—primary report of a single center cohort

Abstract Background Urinary tract infection (UTI) is very common in patients with urolithiasis, which makes the treatment of urolithiasis complicated, even dangerous. The objective of this study was to determine the risk factors for UTI in patients with urolithiasis. Methods Eight hundred six patients with urolithiasis were retrospectively evaluated in the fourth affiliated hospital of China Medical University. All patients admitted to the study were divided into either a UTI infection group or a non-infection group. Sex, age, smoking, stone shape, alcohol consumption, position of stones, and presence of obstruction were used as exposure factors for the cross-sectional study. Results One hundred seventy-eight patients (22.0%) had UTI. Through a urine culture test, gram-negative bacilli were the most common pathogen, followed by gram-positive bacilli and fungi. Conclusions Sex, age, obstruction, stone shape, and multiple sites of stones could be considered the independent factors for UTI in patients with urolithiasis; smoking and drinking had no statistically significant correlation with the condition. Gram-negative bacilli are the most common pathogen in UTI in patients with urolithiasis

Effect of Ca and Zr Additions on Microstructure and Mechanical Properties of As-Extruded Mg-3Sn Alloy

In this paper, the effect of Ca and Zr additions on microstructure and mechanical properties at room temperature of Mg-Sn alloys was investigated by comparison of Mg-3Sn (wt.%) (T3), Mg-3Sn-1Ca (wt.%) (TX31), and Mg-3Sn-1Ca-1Zr (wt.%) (TXK311) alloys under extrusion. The results show that the main phases of as-extruded T3 alloy were α-Mg and Mg2Sn phases, while the CaMgSn phase was formed and the precipitation of Mg2Sn phase was inhibited in the TX31 and TXK311 alloys due to the addition of the Ca element. Zr did not form intermetallic compounds with other elements but dissolved in the grains of the matrix and became nucleating particles. Incomplete dynamic recrystallization (DRX) occurred in all alloys during hot extrusion. The coarse rod-like and fine block-like mixed CaMgSn phase was observed in α-Mg matrix of as-extruded samples of the TX31 alloy, and the dispersed granular CaMgSn phase was observed in the TXK311 alloy. Ca inhibited the dynamic recrystallization behavior of the alloys, while Zr promoted the dynamic recrystallization behavior. All the as-extruded alloys exhibit typical fiber texture of {0001} basal//ED. With the addition of Ca and Zr elements, the particle stimulated nucleation (PSN) effect excited by the second phase particles gradually weakened the texture. TXK311 alloy has good comprehensive mechanical properties at room temperature, with tensile strength, yield strength, and elongation of 261 MPa, 244 MPa, and 11%, respectively, and the average grain size was 1.8 μm. Grain refinement and second phase dispersion strengthening are considered to play critical roles in the strength optimization of the TXK311 alloy

Improved Stability of a Stable Crystal Form C of 6S-5-Methyltetrahydrofolate Calcium Salt, Method Development and Validation of an LC–MS/MS Method for Rat Pharmacokinetic Comparison

Folate is a vitamin beneficial for humans that plays an important role in metabolism, but it cannot be well supplemented by food; it is necessary to supplement it in other ways. Based on this consideration, a novel crystal form C of 6S-5-methyltetrahydrofolate calcium salt (MTHF CAC) was obtained. To explore the difference between MTHF CAC and the crystal form Ⅰ of 6S-5-methyltetrahydrofolate calcium salt (MTHF CA) as well as an amorphous product of 6S-5-methyltetrahydrofolate glucosamine salt (MTHF GA), their stability and pharmacokinetic behaviours were compared. The results of high-performance liquid chromatography coupled with ultraviolet detection analysis indicated that MTHF CAC showed a better stability than MTHF CA and MTHF GA. After oral administration of MTHF CAC, MTHF CA, and MTHF GA to male rats, the MTHF concentrations were analysed using a validated liquid chromatography–tandem mass spectrometry, and the pharmacokinetic parameters were compared. The mean residence times (0–t) of MTHF CAC, MTHF CA, and MTHF GA were 3.7 ± 1.9 h, 1.0 ± 0.2 h (p < 0.01), and 1.5 ± 0.3 h (p < 0.05), respectively. The relative bioavailability of MTHF CAC was calculated to be 351% and 218% compared with MTHF CA and MTHF GA, respectively, which suggests that MTHF CAC can be better absorbed and utilized for a longer period of time

Biomarker Discovery for Detecting the Seed Ageing Degree and Priming Effect of Tobacco

Seed ageing is an important issue for the long-time seed storage of tobacco. Seed priming has been popularly applied in tobacco production. In this study, the development of molecular marker genes encoding proteins L-isoaspartyl methyltransferase NtPIMT1 and 8-oxoG DNA glycosylase 1 NtOGG1 to detect the degree of seed ageing and the effect of seed priming is conducted in tobacco. Quantitative real-time PCR (qRT-PCR) analysis reveals that relatively higher mRNAs of NtPIMT1 and NtOGG1 are observed in the dry and early germinating seeds. The expressions of NtPIMT1 and NtOGG1 are negatively correlated with the degree of seed damage in non-pelleted and pelleted seeds after accelerated ageing treatments. The early best effects of gibberellin (GA3) priming on speed and uniform germination are observed in 33 h primed seeds, and relatively lower expressions of NtPIMT1 and NtOGG1 are observed in priming seeds. NtPIMT1 and NtOGG1 genes have potential for use as molecular markers in detecting the seed ageing degree and priming effect of tobacco

Biomarker Discovery for Detecting the Seed Ageing Degree and Priming Effect of Tobacco

Seed ageing is an important issue for the long-time seed storage of tobacco. Seed priming has been popularly applied in tobacco production. In this study, the development of molecular marker genes encoding proteins L-isoaspartyl methyltransferase NtPIMT1 and 8-oxoG DNA glycosylase 1 NtOGG1 to detect the degree of seed ageing and the effect of seed priming is conducted in tobacco. Quantitative real-time PCR (qRT-PCR) analysis reveals that relatively higher mRNAs of NtPIMT1 and NtOGG1 are observed in the dry and early germinating seeds. The expressions of NtPIMT1 and NtOGG1 are negatively correlated with the degree of seed damage in non-pelleted and pelleted seeds after accelerated ageing treatments. The early best effects of gibberellin (GA3) priming on speed and uniform germination are observed in 33 h primed seeds, and relatively lower expressions of NtPIMT1 and NtOGG1 are observed in priming seeds. NtPIMT1 and NtOGG1 genes have potential for use as molecular markers in detecting the seed ageing degree and priming effect of tobacco