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In this paper, the generation of relativistic electron mirrors (REM) and the reflection of an ultra-short laser off the mirrors are discussed, applying two-dimension particle-in-cell simulations. REMs with ultra-high acceleration and expanding velocity can be produced from a solid nanofoil illuminated normally by an ultra-intense femtosecond laser pulse with a sharp rising edge. Chirped attosecond pulse can be produced through the reflection of a counter-propagating probe laser off the accelerating REM. In the electron moving frame, the plasma frequency of the REM keeps decreasing due to its rapid expansion. The laser frequency, on the contrary, keeps increasing due to the acceleration of REM and the relativistic Doppler shift from the lab frame to the electron moving frame. Within an ultra-short time interval, the two frequencies will be equal in the electron moving frame, which leads to the resonance between laser and REM. The reflected radiation near this interval and corresponding spectra will be amplified due to the resonance. Through adjusting the arriving time of the probe laser, a certain part of the reflected field could be selectively amplified or depressed, leading to the selective adjustment of the corresponding spectra.
Porphyromonas gingivalis has been linked to the development and progression of oesophageal squamous cell carcinoma (ESCC), and is considered to be a high-risk factor for ESCC. Currently, the commonly used methods for P. gingivalis detection are culture or DNA extraction-based, which are either time and labour intensive especially for high-throughput applications. We aimed to establish and evaluate a rapid and sensitive direct quantitative polymerase chain reaction (qPCR) protocol for the detection of P. gingivalis without DNA extraction which is suitable for large-scale epidemiological studies. Paired gingival swab samples from 192 subjects undergoing general medical examinations were analysed using two direct and one extraction-based qPCR assays for P. gingivalis. Tris-EDTA buffer-based direct qPCR (TE-direct qPCR), lysis-based direct qPCR (lysis-direct qPCR) and DNA extraction-based qPCR (kit-qPCR) were used, respectively, in 192, 132 and 60 of these samples for quantification of P. gingivalis. The sensitivity and specificity of TE-direct qPCR was 95.24% and 100% compared with lysis-direct qPCR, which was 100% and 97.30% when compared with kit-qPCR; TE-direct qPCR had an almost perfect agreement with lysis-direct qPCR (κ = 0.954) and kit-qPCR (κ = 0.965). Moreover, the assay time used for TE-direct qPCR was 1.5 h. In conclusion, the TE-direct qPCR assay is a simple and efficient method for the quantification of oral P. gingivalis and showed high sensitivity and specificity compared with routine qPCR.
The conventional repetitive transcranial magnetic stimulation (rTMS) has some inadequate of efficacy weak and inadequate for the treatment of depression, easy symptomatic recurrence when stop the treatment. Ours invented the device of sleep electroencephalogram-modulated rTMS (SEM-rTMS) were safe and effective by proved of the animal experiments and clinical pre-test for the treatment of depression. The purpose of this study was to examine the efficacy and safety of SEM-rTMS for the treatment of depression.
After 7 days without psychoactive medication, 164 patients with clinically defined depression, were randomly assigned to receive SEM-rTMS (N = 57), conventional rTMS (C-rTMS (N = 55), or sham-rTMS (N = 52) for 30 minutes/time/day for 10 days. Before and after scores on the 24-item Hamilton rating scale for depression (HAMD-24) and the clinical outcome at the 10th-day of therapy for all subjects were analyzed.
Twenty two cases in the SEM-rTMS group improved mood as compared to 6 in the C-rTMS group and 2 in the sham-rTMS group (c2 = 15.89, p = 0.0004). After completion of the rTMS phase of the protocol, a (51 ± 5) % reduction of HAMD-24 scores from the baseline in the SEM-rTMS group compared with a (34 ± 4)% in the C-rTMS group ((q = 26.09, p = 0.001) and a (14 ± 3)% in Sham-rTMS group (q = 57.53,p = 0.000). The 88% total efficacy ratio in the SEM-rTMS group was significant higher than 68% in the C-rTMS group and 20% in the sham-rTMS group (c2 = 12.01, p = 0.0025). No significant side effects were noted.
It is efficient and safe to treat depression with repetitive transcranial magnetic stimulation. (The registration. No: ChiCTR-TRC-00000438).
To investigate the effects of sleep electroencephalogram-modulated repetitive transcranial magnetic stimulation (SEM-rTMS) and conventional rTMS (C-rTMS) on the activity of hypothalamic-pituitary-adrenal (HPA) axis in patients with depression.
In a double-blind, randomized controlled trial, 164 patients diagnosed with depression were randomized to treatment with SEM-rTMS (n = 57), C-rTMS (n = 55) or sham rTMS (n = 52) for 30 min every day for 10 d. Before and after treatment plasma concentrations of adrenocorticotropic hormone (ACTH) and cortisol (CORT) were measured, and the 24-item Hamilton Depression Rating Scale (HAMD-24) was used for assessment.
The HAMD-24 scores and plasma ACTH and CORT concentrations of these depressive patients before treatment were significantly different from those of the normal control group (P < 0.05). The HAMD-24 scores and plasma ACTH and CORT concentrations in the SEM-r TMS group and conventional rTMS group were decreased significantly (P < 0.05). There was a significant positive correlation between the HAMD-24 scores and plasma ACTH (n = 240, r = 0.105, P = 0.048) and CORT concentrations (n = 240, r = 0.126, P = 0.023) in the patients with depression before and after treatment.
The antidepressant effect of rTMS, including SEM-rTMS, may be related to its decreasing HPA axis activity. (This trail was registered. No: ChiCTR-TRC-00000465).
Triploid and pentaploid breeding is of great importance in agricultural production, but it is not always easy to obtain double ploidy parents. However, in fishes, chromosome ploidy is diversiform, which may provide natural parental resources for triploid and pentaploid breeding. Both tetraploid and hexaploid exist in Schizothorax fishes, which were thought to belong to different subfamilies with tetraploid Percocypris fishes in morphology, but they are sister genera in molecule. Fortunately, the pentaploid hybrid fishes have been successfully obtained by hybridization of Schizothorax wangchiachii (♀, 2n = 6X = 148) × Percocypris pingi (♂, 2n = 4X = 98). To understand the genetic and morphological difference among the hybrid fishes and their parents, four methods were used in this study: morphology, karyotype, red blood cell (RBC) DNA content determination and inter-simple sequence repeat (ISSR). In morphology, the hybrid fishes were steady, and between their parents with no obvious preference. The chromosome numbers of P. pingi have been reported as 2n = 4X = 98. In this study, the karyotype of S. wangchiachii was 2n = 6X = 148 = 36m + 34sm + 12st + 66t, while that the hybrid fishes was 2n = 5X = 123 = 39m + 28sm + 5st + 51t. Similarly, the RBC DNA content of the hybrid fishes was intermediate among their parents. In ISSR, the within-group genetic diversity of hybrid fishes was higher than that of their parents. Moreover, the genetic distance of hybrid fishes between P. pingi and S.wangchiachii was closely related to that of their parental ploidy, suggesting that parental genetic material stably coexisted in the hybrid fishes. This is the first report to show a stable pentaploid F1 hybrids produced by hybridization of a hexaploid and a tetraploid in aquaculture.
A multi-scale strategy is employed in the paper to investigate the thermo-mechanical properties of 2.5D angle-interlock woven shape memory polymer composites (SMPCs). In the study, the mesoscopic model of 2.5D woven SMPCs and microscopic model of yarns are firstly developed. After that, the themo-viscoelastic constitutive relationship of the yarn is described in the form of hereditary integral and the parameters of relaxation moduli are obtained from nonlinear fitting of Prony series based on the results of finite element method (FEM). Based on the multi-scale models and the constitutive relationship, the effects of warp and weft arranged densities on viscoelastic properties of 2.5D woven SMPCs are studied in detail. Finally, the shape memory behavior along the warp direction in small strain region is also analyzed. The research in the paper lays a foundation for design and application of woven SMPCs in engineering.
Previously, we reported a phylogenetic study of 98 Burkholderia pseudomallei clinical isolates from Hainan, China. Here, we update the B. pseudomallei strain library with 52 strains from newly identified cases dating from 2014 to 2017, analysed by multilocus sequence typing. Twenty-two sequence types (STs) were identified from the 52 cases, illustrating high genetic diversity; five of them (ST1480, ST1481, ST1482, ST1483 and ST1484) were novel. ST46, ST50 and ST58 predominated (34.6%) as was the case in the previous study (35.7%). An e-BURST map of the ST profiles of the two collections of isolates showed their genetic foundation to be largely unchanged. Neighbour-joining tree analysis was suggestive of a close phylogenetic relationship between the novel STs from this series and those first reported from Hainan (ST1105, ST1099, ST55 and ST1095). Moreover, the two novel STs (1481 and 1483) showed close similarity to ST58 which originated in Thailand indicating a close relationship between B. pseudomallei strains from both countries. The previously described allele profiles gmhD-36 and lepA-68 were found for the first time in our strain collections. Our study emphasises the importance of monitoring the epidemiological status and evolutionary trends of B. pseudomallei in China.
Thousand Island Lake (TIL) is a typical fragmented landscape and an ideal model to study ecological effects of fragmentation. Partial fragments of the mitochondrial cytochrome oxidase subunit I gene of 23 island populations of Dendrolimus punctatus in TIL were sequenced, 141 haplotypes being identified. The number of haplotypes increased significantly with the increase in island area and shape index, whereas no significant correlation was detected between three island attributes (area, shape and isolation) and haplotype diversity. However, the correlation with number of haplotypes was no longer significant when the ‘outlier’ island JSD (the largest island) was not included. Additionally, we found no significant relationship between geographic distance and genetic distance. Geographic isolation did not obstruct the gene flow among D. punctatus populations, which might be because of the high dispersal capacity of this pine moth. Fragmentation resulted in the conversion of large and continuous habitats into isolated, small and insular patches, which was the primary effect on the genetic diversity of D. punctatus in TIL. The conclusion to emphasize from our research is that habitat fragmentation reduced the biological genetic diversity to some extent, further demonstrating the importance of habitat continuity in biodiversity protection.
The triplite LiFeSO4F displays both the highest potential ever reported for an Fe-based compound, as well as a comparable specific energy with that of popular LiFePO4. The synthesis is still a challenge because the present approaches are connected with long time, special equipments or organic reagents, etc. In this work, the triplite LiFeSO4F powder was synthesized through an ambient two-step solid-state route. The reaction process and phase purity were analyzed, coupled with structure refinement and electrochemical test.
Muons produced by the Bethe–Heitler process from laser wakefield accelerated electrons interacting with high
materials have velocities close to the laser wakefield. It is possible to accelerate those muons with laser wakefield directly. Therefore for the first time we propose an all-optical ‘Generator and Booster’ scheme to accelerate the produced muons by another laser wakefield to supply a prompt, compact, low cost and controllable muon source in laser laboratories. The trapping and acceleration of muons are analyzed by one-dimensional analytic model and verified by two-dimensional particle-in-cell (PIC) simulation. It is shown that muons can be trapped in a broad energy range and accelerated to higher energy than that of electrons for longer dephasing length. We further extrapolate the dependence of the maximum acceleration energy of muons with the laser wakefield relativistic factor
and the relevant initial energy
. It is shown that a maximum energy up to 15.2 GeV is promising with
on the existing short pulse laser facilities.
Resonant acceleration of electrons by a laser in the background of an extra longitudinal magnetic field is investigated analytically and numerically. The resonant condition is independent of laser intensity, and when satisfied, the energy gain is proportional to
and the square of phase difference. This process is mainly limited by the magnitude and spatial size of the extra magnetic field. Under the laboratory conditions, simulation results show that a monoenergetic and collimated electron bunch can still be obtained in ~ GV/cm scale, which sheds a light on the vacuum table-top laser-driven electron accelerators.
The origin and characteristics of near-microcoulomb multi-MeV electrons accelerated by short pulse lasers interacting with near-critical density plasma in self-formed channels are studied using three-dimensional particle-in-cell simulations. According to the analysis on interaction phenomena and electron dynamics, the dominant mechanism turns out to be direct laser acceleration, which ensures the outstanding energy coupling. Additionally, self-channeling is found to be a decisive factor for the acceleration performance, as electrons obtain ultra-high energy through betatron resonance inside the channels. In our findings, by using a relativistic short laser pulse and near-critical plasma, a large amount of energetic electrons can be generated, presenting a promising and accessible route to ultraintense, high-spatial-resolution radiation pulses.
Relativistic collisionless shock charged particle acceleration is considered as a possible origin of high-energy cosmic rays. However, it is hard to explore the nature of relativistic collisionless shock due to its low occurring frequency and remote detecting distance. Recently, there are some works attempt to solve this problem by generating relativistic collisionless shock in laboratory conditions. In laboratory, the scheme of generation of relativistic collisionless shock is that two electron–positron pair plasmas knock each other. However, in laboratory, the appropriate pair plasmas have been not generated. The 10 PW laser pulse maybe generates the pair plasmas that satisfy the formation condition of relativistic collisionless shock due to its ultrahigh intensity and energy. In this paper, we study the positron production by ultraintense laser high Z target interaction using numerical simulations, which consider quantum electrodynamics effect. The simulation results show that the forward positron beam up to 1013/kJ can be generated by 10 PW laser pulse interacting with lead target. The estimation of relativistic collisionless shock formation shows that the positron yield satisfies formation condition and the positron divergence needs to be controlled. Our results indicate that the generation of relativistic collisionless shock by 10 PW laser facilities in laboratory is possible.
A scheme for the improvement of proton beam quality by the optimized dragging field from the interaction of ultraintense laser pulse with a complex double-layer target is proposed and demonstrated by one-dimensional particle-in-cell (Opic1D) simulations. The complex double-layer target consists of an overdense proton thin foil followed by a mixed hydrocarbon (CH) underdense plasma. Because of the existence of carbon ions, the dragging field in the mixed CH underdense plasma becomes stronger and flatter in the location of the proton beam than that in a pure hydrogen (H) underdense plasma. The optimized dragging field can keep trapping and accelerating protons in the mixed CH underdense target to high quality. Consequently, the energy spread of the proton beam in the mixed CH underdense plasma can be greatly reduced down to 2.6% and average energy of protons can reach to 9 GeV with circularly polarized lasers at intensities 2.74 × 1022 W/cm2.
Soluble starch synthase II (SSII) plays an important role in the biosynthesis of starch and in rice it consists of three isoforms encoded by SSII-1, SSII-2 and SSII-3. However, the genetic effects of various SSII alleles on grain quality have not been systematically characterized. In the present study, the japonica alleles on SSII-1, SSII-2 and SSII-3 (SSIIa) loci from a japonica cultivar, Suyunuo, were respectively introgressed by molecular marker-assisted selection into a typical indica cultivar, Guichao2, through successive backcrossing, generating three sets of near-isogenic lines (NILs). Grain quality and starch property analysis showed that NIL-SSII-3j exhibited significant decreases in the following parameters: amylose content, average granule size, and setback viscosity and consistency; but increases in peak viscosity, hot paste viscosity, gelatinization temperature and relative crystallinity. Moreover, the proportion of short amylopectin chains and branching degree also increased when compared with those of NIL-SSII-3i (Guochao2). Similar effects were observed in NIL-SSII-1j, and certain alterations in the fine structure of starch (granule size) were revealed. However, NIL-SSII-2j did not exert significant effect on grain quality and starch properties. In brief, among the SSII gene family, the functional diversity occurred on SSII-1 and SSII-3, and not on SSII-2. Therefore, it appears that more attention should be directed to SSII-1 and SSII-3 loci for improving the eating and cooking quality of rice.
The phylogenetic and epidemiological relationships of 102 Burkholderia pseudomallei clinical isolates from different geographical and population sources in China were investigated by multilocus sequence typing (MLST). The MLST data were analysed using the e-BURST algorithm, and an unweighted pair-group method with arithmetic mean dendrogram was constructed based on the pair-wise differences in the allelic profiles of the strains. Forty-one sequence types (STs) were identified, of which eight were novel (ST1341, ST1345, ST1346, ST1347, ST1348, ST1349, ST1350, ST1351). No geographical-specific or host population-specific phylogenetic lineages were identified. ST46, ST50, ST55, ST58, ST70 and ST1095 predominated, but ~44% of isolates were assigned to 45 STs illustrating high genetic diversity in the strain collection. Additionally, the phylogenetic relationships of the dominant STs in China showed significant linkeage with B. pseudomallei isolates from Thailand. Analysis of the gmhD allele suggests high genetic variation in B. pseudomallei in China.
Nursing homes (NHs) have been implicated as significant reservoirs of antibiotic-resistant organisms causing severe infectious disease. We investigated the prevalence and molecular epidemiology of, and risk factors for, faecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E). A multicentre cross-sectional study was conducted in seven NHs in Shanghai between March 2014 and May 2014. Antimicrobial susceptibility testing and polymerase chain reaction were used to detect genes coding for ESBLs and carbapenemases. NH records at individual-resident level and facility level were examined for potential risk factors. Four hundred and fifty-seven Enterobacteriaceae isolates were collected of which 183 (46·92%) were colonized by ESBL-E. CTX-M enzymes (198/200, 99%) predominated, with CTX-M-14 (84/200, 42%) the most common types. Two carbapenemase producers harboured blaKPC-2. Resistance rates to carbapenems, TZP, AK, FOS, CL and TGC were low. History of invasive procedures [odds ratio (OR) 2·384, 95% confidence interval (CI) 1·318–4·310, P = 0·004], narrow-spectrum cephalosporins (OR 1·635, 95% CI 1·045–2·558, P = 0·031) and broad-spectrum cephalosporins (OR 3·276, 95% CI 1·278–8·398, P = 0·014) were independently associated with ESBL-E carriage. In conclusion, NH residents have a very high prevalence of faecal carriage of ESBL-E. Continuous and active surveillance is important, as are prudent infection control measures and antibiotic use to prevent and control the spread of these antibiotic-resistant strains.
Molecular imprinting is the process by which molecules are imprinted into the matrix of a material through non-covalent bonding, including hydrogen bonding and van der Waals interactions. In this study hydrogels were imprinted with glaucoma medication with the purpose of creating a reusable ocular drug delivery device with reversible binding sites. The material was synthesized and tested with UV-Vis spectroscopy to determine the concentration of the released drug after twelve hours in distilled water. Modifications were made to the polymer to explore methods required for the proper delivery of the drug over an adequate period of time.
Polymeric nanoparticles having redox-active catechol moieties, a common structural motif found in naturally-occurring antioxidants, were developed. We synthesized an amphiphilic catechol-bearing polymer that self-assembled to form nanoparticles with a diameter of 126 nm. The nanoparticles showed enhanced ROS-scavenging activity compared to the small catecholic compound dopamine. Furthermore, the nanoparticles inhibited ROS-mediated angiogenesis as shown by the endothelial cell tube formation assay and the chicken chorioallantoic membrane (CAM) assay.