Search

Dark matter (DM) is a major constituent of the Universe. However, no definite evidence of DM particles (denoted as "χ") has been found in DM direct detection (DD) experiments to date. There is a novel concept of detecting χ from evaporating primordial black holes (PBHs). We search for χ emitted from PBHs by investigating their interaction with target electrons. The examined PBH masses range from 1 × 1015 to 7 × 1016 g under the current limits of PBH abundance fPBH. Using 205.4 kg·day data obtained from the CDEX-10 experiment conducted in the China Jinping Underground Laboratory, we exclude the χ-electron (χ-e) elastic-scattering cross section σ χ e ∼ 5 × 10−29 cm2 for χ with a mass mχ ≲ 0.1 keV from our results. With the higher radiation background but lower energy threshold (160 eV), CDEX-10 fills a part of the gap in the previous work. If ( m χ , σ χ e ) can be determined in the future, DD experiments are expected to impose strong constraints on fPBH for large MPBHs. [ABSTRACT FROM AUTHOR]

The patterns of communication among different chondrocyte subtypes in human cartilage degeneration and regeneration help us understand the microenvironment of osteoarthritis and optimize cell-targeted therapies. Here, a single-cell transcriptome dataset of chondrocytes is used to explore the synergistic and communicative patterns of different chondrocyte subtypes. We collected 1600 chondrocytes from 10 patients with osteoarthritis and analyzed the active communication patterns for the first time based on network analysis and pattern recognition at the single-cell level. Manifold learning and quantitative contrasts were performed to analyze conserved and specific communication pathways. We found that ProCs (Proliferative chondrocytes), ECs (Effector chondrocytes), preHTCs (Prehypertrophic chondrocytes), HTCs (Hypertrophic chondrocytes), and FCs (Fibrocartilage chondrocytes) are more active in incoming and outgoing signaling patterns, which is consistent with studies on their close functional cooperation. Among them, preHTCs play multiple roles in chondrocyte communication, and ProCs and preHTCs have many overlapping pathways. These two subtypes are the most active among all chondrocyte subtypes. Interestingly, ECs and FCs are a pair of "mutually exclusive" subtypes, of which ECs are predominant in incoming patterns and FCs in outgoing patterns. The active signaling pathways of ECs and FCs largely do not overlap. COLLAGEN and LAMININ are the main pivotal pathways, which means they are very important in the repair and expansion of joint homeostasis. Notably, only preHTCs assume multiple roles (including sender, receiver, mediator, and influencer) and are involved in multiple communication pathways. We have examined their communication patterns from the perspective of cellular interactions, revealed the relationships among different chondrocyte subtypes, and, in particular, identified a number of active subtypes and pathways that are important for targeted therapy in the osteoarthritic microenvironment. Our findings provide a new research paradigm and new insights into understanding chondrocyte activity patterns in the osteoarthritic microenvironment. [ABSTRACT FROM AUTHOR]

Purpose: Only recently has the percentage of signet-ring cells (SRCs) been shown to affect the prognosis following gastric cancer surgery. It is uncertain whether the SRC percentage has a role in tumour biology or prognosis of gastric signet-ring cell carcinoma (GSRCC). For this research, we assessed the effect of the SRC percentage on the clinicopathological and prognostic characteristics of gastric cancer (GC) tumours and created and verified a prognostic nomogram to assess the overall survival (OS) of GSRCC patients. Methods: In our study, 1100 GC patients with signet-ring cell carcinoma (SRCC) at Zhejiang Cancer Hospital from December 2013 to December 2018 who underwent curative gastric cancer resection were retrospectively analysed. The patients were separated into two groups: those with SRCC (SRC percentage >50%; n = 157) and those with partial signet-ring cell carcinoma (PSRCC) (SRC percentage ≤50%; n = 943). We compared the clinicopathological characteristics of both groups. To estimate OS and determine correlations with the SRC percentage, the Kaplan-Meier method and log-rank test were used. To develop the prognostic nomogram, independent prognostic indicators for OS were identified using Cox regression analyses. Predictions were assessed using the calibration curve and C-index. Results: Our research showed that there was no discernible difference in OS between the two groups. The preoperative CA242 level, pT stage, pN stage, age, nerve invasion, neoadjuvant chemotherapy, postoperative chemotherapy, and maximum tumour diameter were independent prognostic risk factors for OS for GC (all p < 0.05). However, for advanced GC, the SRC percentage (HR = 1.571, 95% CI 1.072–2.302, p = 0.020) was an independent prognostic factor of OS. Other independent prognostic risk factors were age, pT stage, pN stage, nerve invasion, tumour location, neoadjuvant chemotherapy, postoperative chemotherapy, preoperative CA50 level, and preoperative CEA level (all p < 0.05). On these bases, nomograms were constructed for GC and advanced GC, with C-indexes of 0.806 (95%CI 0.782–0.830) and 0.728 (95%CI 0.697–0.759), respectively. Conclusions: In cases of advanced gastric cancer, the SRC percentage served as a standalone prognostic indicator for OS. An effective tool for assessing the prognosis of GSRCC was offered by the nomogram. [ABSTRACT FROM AUTHOR]

PET-MRI fusion images are of great significance in improving diagnostic accuracy and nursing quality. However, existing fusion methods usually subjectively define fusion rules to retain specific fusion regions, which will lead to information distortion. Complex processes or network design can also significantly slow down fusion speed. The fusion results of unsupervised models without artificially setting fusion rules are usually poor. To address these limitations, we designed an unsupervised model to accomplish the fusion of MRI-PET brain images. We use the attention modules CBAM (convolutional block attention module) and AG (attention gate) to dynamically highlight the salient features, and the ASPP (arous spatial pyramid pooling) module and residual structure are used to maximize the preservation of source image information. The unique design of each module saves us a lot of computational costs. In addition, we designed a fusion strategy for separating the bone density information and the fusion region, which solves the problem of MRI bone density information retention during image fusion. We have done lots of experiments to verify the superiority of the model. In comparison with the state-of-the-art methods, our model has a higher QG than FusionDN at 68.9% and a Qs than U2Fusion at 120.49%, and the fusion efficiency has also reached a high level. [ABSTRACT FROM AUTHOR]

Background: Anastomotic mediastinal/pleural cavity leak (AMPCL) is a life-threatening postoperative complication after esophagectomy. The objective of this study was to find a safe and effective surgical method to reduce the incidence of AMPCL. Methods: A total of 223 patients who underwent surgery in Fujian Medical University Union Hospital from May 2020 to October 2021 were enrolled in this study. Data for preoperative and postoperative test indices, postoperative complications, perioperative treatment were collected. After using 1:1 propensity score matching (PSM) to match two cohort (caliper = 0.1), the relationship between various factors and the incidence of AMPCL were analyzed. Results: 209 patients were included for further analysis in the end. There were 95 patients in the sternocleidomastoid muscle flap embedding group (intervention group) and 114 in the routine operation group (control group). There was a significant difference in mean age between two groups. Gender, age, body mass index, diabetes, American society of anesthesiologists score, preoperative neoadjuvant therapy, pathological stage were included in performing 1:1 PSM, and there were no significant differences between two groups. Median operative time was significantly less in intervention group. Anastomotic leak (AL) did not present significant difference between two groups (8 [8.6] vs. 13 [14.0], p = 0.247), however, the AMPCL in intervention group was significantly lower than control group (0 [0] vs. 6 [6.5], p = 0.029). Conclusions: The sternocleidomastoid muscle flap embedding could significantly reduce the incidence of AMPCL. This additional procedure is safe, and effective without increase in the occurrence of postoperative complications and hospital expenses. [ABSTRACT FROM AUTHOR]

Efficient, accurate molecular characterization of genetically modified (GM) organisms is challenging, especially for those transgenic events transferred with genes/elements of recipient species. Herein, we decipher the comprehensive molecular characterization of one novel GM rice event G281 which was transferred with native promoters and an RNA interference (RNAi) expression cassette using paired-end whole genome sequencing (PE-WGS) and modified TranSeq approach. Our results show that transgenes integrate at rice chromosome 3 locus 16,439,674 included a 36 bp deletion of rice genomic DNA, and the whole integration contains two copies of the complete transfer DNA (T-DNA) in a head-to-head arrangement. No unintended insertion or backbone sequence of the transformed plasmid is observed at the whole genome level. Molecular characterization of the G281 event will assist risk assessment and application for a commercial license. In addition, we speculate that our approach could be further used for identifying the transgene integration of cisgenesis/intragenesis crops since both ends of T-DNA in G281 rice were from native gene or elements which is similar with that of cisgenesis/intrasgenesis. Our results from the in silico mimicking cisgenesis event confirm that the mimic rice Gt1 gene insertion and its flanking sequences are successfully identified, demonstrating the applicability of PE-WGS for molecular characterization of cisgenesis/intragenesis crops. Coupling paired-end whole-genome sequencing with droplet digital PCR enabled precise identification of a transgene insertion in the genetically modified rice event G281 on chromosome 3 and the potential for exploring the native gene integration. [ABSTRACT FROM AUTHOR]

Formins are actin-binding proteins that are key to maintaining the actin cytoskeleton in cells. However, molecular mechanisms controlling the stability of formin proteins in plants remain unknown. Here, we have identified six rice SIAH-type E3 ligases, named RIP1-6 (RMD Interacting Protein 1–6) respectively, with ubiquitination enzyme activity in vitro. All six proteins can form homo- and hetero-dimers with themselves, and hetero-dimers with type II formin RMD/OsFH5. In vivo assays showed that RIP1-6 proteins localize in the cytoplasm with a punctate distribution, and all of them interact with RMD to change its native diffuse cytoplasmic localization to match that of RIP1-6. To our surprise, degradation experiments revealed that RIP1, RIP5, and RIP6 decrease rather than increase the degradation rate of RMD. Genetic analyses revealed redundancy between these six genes; either single or double mutants did not show any obvious phenotypes. However, the sextuple rip1-6 mutant displayed dwarf height, wrinkled seeds and wider leaves that were similar to the previously reported rmd mutant, and defective microfilaments and increased flag leaf angles that were not reported in rmd mutant. Collectively, our study provides insights into the mechanisms determining formin protein stability in plants. [ABSTRACT FROM AUTHOR]

We present weakly interacting massive particles (WIMPs) search results performed using two approaches of effective field theory from the China Dark Matter Experiment (CDEX), based on the data from both CDEX-1B and CDEX-10 stages. In the nonrelativistic effective field theory approach, both time-integrated and annual modulation analyses were used to set new limits for the coupling of WIMP-nucleon effective operators at 90% confidence level (C.L.) and improve over the current bounds in the low mχregion. In the chiral effective field theory approach, data from CDEX-10 were used to set an upper limit on WIMP-pion coupling at 90% C.L. We for the first time extended the limit to the mχ < 6 GeV/c2 region. [ABSTRACT FROM AUTHOR]

We study the freeze-in production of Feebly Interacting Massive Particle (FIMP) dark matter candidates through a neutrino portal. We consider a hidden sector comprised of a fermion and a complex scalar, with the lightest one regarded as a FIMP candidate. We implement the Type-I Seesaw mechanism for generating the masses of the Standard Model (SM) neutrinos by introducing three heavy neutrinos which are assumed to be degenerated, for simplicity, and are also responsible for mediating the interactions be- tween the hidden and the SM sectors. We assume that an early matter-dominated (EMD) era took place for some period between inflation and Big Bang Nucleosynthesis, making the Universe to expand faster than in the standard radiation-dominated era. In this case, the hidden and SM sectors are easily decoupled and larger couplings between FIMPs and SM particles are needed from the relic density constraints. In this context, we discuss the dynamics of dark matter throughout the modified cosmic history, evaluate the relevant constraints of the model and discuss the consequences of the duration of the EMD era for the dark matter production. Finally, we show that if the heavy neutrinos are not part of the thermal bath, this scenario becomes testable through indirect detection searches. [ABSTRACT FROM AUTHOR]

Continuous growing of exhaustive crops like sugarcane and imbalanced use of fertilizers would deplete the soil nutrients, degrade its health and ultimately restrict the crop growth. Biochar due to its unique nature can improve soil health, plant growth and nutrient distribution. The pot experiment was carried out with the biochar which derived from cassava straw additions of 0 t/ha (C0), 10 t/ha (C10) and 20 t/ha (C20), respectively. The biomass, green leaf number, leaf area, shoot/root ratio, photosynthetic characteristics and nitrogen, phosphorus and potassium nutrient contents were measured during sugarcane seedling, elongating and maturity stages to analyze the effect of biochar on sugarcane growth. The results showed that biochar application improved leaf biomass from 7.80 to 50.40%. However, biochar addition did not show a significant increase in sugarcane total biomass except form leaf biomass. Total biomass of sugarcane showed the coherent pattern of 0.20%, − 4.24% and 5.81% for C10 and 1.74%, 11.98% and − 1.83% for C20 at seedling, elongation and maturity stages, respectively. The accumulation of nitrogen, phosphorus and potassium contents in leaves, shoots and roots was significantly increased at seedling, elongation and maturity stage, respectively. Furthermore, maximum total nitrogen content (4.64%) for C10, total phosphorus content (11.47 g kg−1) and total potassium content (76.29 g kg−1) for C20 also were higher than those of control at elongation stage. Biochar application significantly increased net photosynthetic rate and decreased transpiration rate during all the growth stages. These findings not only lead us to know that biochar application has positive effect on sugarcane growth, photosynthetic characteristics and nutrients utilization, but also indicate that field trials for several growing cycles are needed to fully understand the effects of biochar on sugarcane growth. [ABSTRACT FROM AUTHOR]

A highly precise, quantitative method based on the droplet digital polymerase chain reaction (ddPCR) technique was developed to identify and quantify the goat and sheep content in meat products. A formula for calculating raw meat weight based on DNA copy number was established. Exclusive specificity was verified using samples from 24 different animal species, and inclusive specificity between goat and sheep was tested using five different breeds for each species. The limit of detection and the limit of quantitation for both goat and sheep were 1 and 5 copies/μL, respectively, using a cloned plasmid containing goat- and sheep-specific target DNA fragments as calibrators. The accuracy and applicability of the method were verified using mixed powder samples with known proportions of goat and sheep meat, simulate meatball samples, and commercially available products, respectively. The results confirmed that the developed ddPCR methods are highly precise for identifying and quantifying the goat and sheep meat, indicating their potential applicability in future routine analyses. [ABSTRACT FROM AUTHOR]

The transgenic maize ( Zea mays L.) line BVLA430101 overexpressing Aspergillus niger phyA2 was approved in 2009 to be planted in a given area in China. However, the flanking sequences and event-specific qualitative/quantitative PCR detection methods for this transgenic event have not been reported. In this study, we characterized the molecular features of the exogenous integration in BVLA430101 and developed event-specific qualitative/quantitative PCR detection methods. Using genome walking, thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR), and conventional PCR assays, we revealed that one intact copy of phytase construct was integrated in the maize genome chromosome 3, which is followed by a fragment of the transformation vector containing partial sequence of pH2b promoter. The defined 3′ flanking sequence was 1644 bp in length, based on which the event-specific qualitative and quantitative PCR assays for BVLA430101 were developed. The limit of detection (LOD) of the qualitative PCR assay was 10 haploid genome copies, and the limits of detection and quantification (LOD and LOQ) of the quantitative PCR were 10 and 10 copies of maize haploid genome, respectively. In-house validation of the developed event-specific quantitative PCR method with three practical maize samples showed that the quantified biases between the test and true values ranged between 2.60 and 7.52 %. These results indicated that the developed event-specific qualitative and quantitative PCR methods based on the newly characterized 3′ flanking sequences can be used successfully for the identification and quantification of transgenic maize BVLA430101 and its derived products. [ABSTRACT FROM AUTHOR]

Key message: Non-targeted metabolomics analysis revealed only intended metabolic changes in transgenic maize over-expressing the Aspergillus niger phyA2. Abstract: Genetically modified (GM) crops account for a large proportion of modern agriculture worldwide, raising increasingly the public concerns of safety. Generally, according to substantial equivalence principle, if a GM crop is demonstrated to be equivalently safe to its conventional species, it is supposed to be safe. In this study, taking the advantage of an established non-target metabolomic profiling platform based on the combination of UPLC-MS/MS with GC-MS, we compared the mature seed metabolic changes in transgenic maize over-expressing the Aspergillus niger phyA2 with its non-transgenic counterpart and other 14 conventional maize lines. In total, levels of nine out of identified 210 metabolites were significantly changed in transgenic maize as compared with its non-transgenic counterpart, and the number of significantly altered metabolites was reduced to only four when the natural variations were taken into consideration. Notably, those four metabolites were all associated with targeted engineering pathway. Our results indicated that although both intended and non-intended metabolic changes occurred in the mature seeds of this GM maize event, only intended metabolic pathway was found to be out of the range of the natural metabolic variation in the metabolome of the transgenic maize. Therefore, only when natural metabolic variation was taken into account, could non-targeted metabolomics provide reliable objective compositional substantial equivalence analysis on GM crops. [ABSTRACT FROM AUTHOR]

In 2009, the genetically modified (GM) rice event TT51-1 with an engineered insect resistance trait became the first GM rice event to be granted certification for safe production in China, and its derivative lines Bt 63 and Huahui No.1 are expected to be commercialized soon. The development of certified reference material (CRM) for TT51-1 is necessary to monitor and inspect the TT51-1 event and its derivates. In this work, we developed four matrix-based TT51-1 rice CRMs (TT51-1, TT51-1, TT51-1, and TT51-1) with different TT51-1 mass fraction ratios by blending seed powders of homozygous TT51-1 and its recipient cultivar Minghui 63. The between-bottle homogeneity and the within-bottle homogeneity were tested, and good results were obtained. The potential degradation during transportation and shelf life were evaluated, and demonstrated an expiration period of at least 36 months. The characterization values of the four TT51-1 CRMs based on the mass fraction ratio were 1000.000 ± 51.430 g/kg, 49.940 ± 4.620 g/kg, 9.990 ± 1.110 g/kg, and 4.990 ± 0.620 g/kg, respectively. The characterization values based on the copy number ratio were certified by digital PCR analysis as 97.442 ± 5.253 %, 4.851 ± 0.486 %, 1.042 ± 0.135 %, and 0.556 ± 0.073 %, respectively. These results suggested that the TT51-1 matrix-based CRMs developed are of high quality and can be used as potential calibrators for TT51-1 GM rice inspection and monitoring. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Isothermal DNA/RNA amplification techniques are the primary methodology for developing on-spot rapid nucleic acid amplification assays, and the loop-mediated isothermal amplification (LAMP) technique has been developed and applied in the detection of foodborne pathogens, plant/animal viruses, and genetically modified (GM) food/feed contents. In this study, one set of LAMP assays targeting on eight frequently used universal elements, marker genes, and exogenous target genes, such as CaMV35S promoter, FMV35S promoter, NOS, bar, cry1Ac, CP4 epsps, pat, and NptII, were developed for visual screening of GM contents in plant-derived food samples with high efficiency and accuracy. For these eight LAMP assays, their specificity was evaluated by testing commercial GM plant events and their limits of detection were also determined, which are 10 haploid genome equivalents (HGE) for FMV35S promoter, cry1Ac, and pat assays, as well as five HGE for CaMV35S promoter, bar, NOS terminator, CP4 epsps, and NptII assays. The screening applicability of these LAMP assays was further validated successfully using practical canola, soybean, and maize samples. The results suggested that the established visual LAMP assays are applicable and cost-effective for GM screening in plant-derived food samples. [ABSTRACT FROM AUTHOR]

Reference materials are important in accurate analysis of genetically modified organism (GMO) contents in food/feeds, and development of novel reference plasmid is a new trend in the research of GMO reference materials. Herein, we constructed a novel multi-targeting plasmid, pSOY, which contained seven event-specific sequences of five GM soybeans (MON89788-5', A2704-12-3', A5547-127-3', DP356043-5', DP305423-3', A2704-12-5', and A5547-127-5') and sequence of soybean endogenous reference gene Lectin. We evaluated the specificity, limit of detection and quantification, and applicability of pSOY in both qualitative and quantitative PCR analyses. The limit of detection (LOD) was as low as 20 copies in qualitative PCR, and the limit of quantification (LOQ) in quantitative PCR was 10 copies. In quantitative real-time PCR analysis, the PCR efficiencies of all event-specific and Lectin assays were higher than 90 %, and the squared regression coefficients (R) were more than 0.999. The quantification bias varied from 0.21 % to 19.29 %, and the relative standard deviations were from 1.08 % to 9.84 % in simulated samples analysis. All the results demonstrated that the developed multi-targeting plasmid, pSOY, was a credible substitute of matrix reference materials, and could be used as a reliable reference calibrator in the identification and quantification of multiple GM soybean events. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effect of biochar application on the seedling root properties in sugarcane. A pot experiment was done with a sugarcane cultivar ROC 22 with 10 and 20 per cent of laterite (weight/weight) and without biochar application for 60 days. Results showed that biochar application resulted in a better improvement for sugarcane root properties at seedling stage, and biochar application treatment resulted in greater shoot-to-root ratio. Biochar application raised the soil pH, and significantly increased concentration of available P, K and organic matter present in biochar with 20 % application. These findings lead us to suggest that further investigations are needed to assess the complete effect of biochar application on nutrient uptake and use efficiency across the whole sugarcane growth cycle. [ABSTRACT FROM AUTHOR]

Cultivation and marketing of genetically modified organisms (GMOs) have been unevenly adopted worldwide. To facilitate international trade and to provide information to consumers, labelling requirements have been set up in many countries. Quantitative real-time polymerase chain reaction (qPCR) is currently the method of choice for detection, identification and quantification of GMOs. This has been critically assessed and the requirements for the method performance have been set. Nevertheless, there are challenges that should still be highlighted, such as measuring the quantity and quality of DNA, and determining the qPCR efficiency, possible sequence mismatches, characteristics of taxon-specific genes and appropriate units of measurement, as these remain potential sources of measurement uncertainty. To overcome these problems and to cope with the continuous increase in the number and variety of GMOs, new approaches are needed. Statistical strategies of quantification have already been proposed and expanded with the development of digital PCR. The first attempts have been made to use new generation sequencing also for quantitative purposes, although accurate quantification of the contents of GMOs using this technology is still a challenge for the future, and especially for mixed samples. New approaches are needed also for the quantification of stacks, and for potential quantification of organisms produced by new plant breeding techniques. [ABSTRACT FROM AUTHOR]

To develop effective alternatives for detecting genetically modified organisms (GMOs), we reported one optimized visual loop-mediated isothermal amplification (LAMP) method for the detection of exogenous DNA targets from two GM soybean events in this study. This isothermal amplification can be performed within 40 min without polymerase chain reaction (PCR) equipment and the derived LAMP products can be directly observed by naked eye employing SybrGreen I dye instead of conventional gel electrophoresis analysis. The limits of detection of these established visual LAMP assays were about 4 copies of haploid soybean genomic DNA, and which were much higher than those of reported conventional PCR assays. Furthermore, the high specificity of LAMP assays was determined. All the results demonstrated that the developed visual LAMP assays are convenient, cost-efficient, and rapid for on spot detection of GMOs. [ABSTRACT FROM AUTHOR]

A reliable PCR reference assay for relative genetically modified organism (GMO) quantification must be specific for the target taxon and amplify uniformly along the commercialised varieties within the considered taxon. Different reference assays for maize ( Zea mays L.) are used in official methods for GMO quantification. In this study, we evaluated the reliability of eight existing maize reference assays, four of which are used in combination with an event-specific polymerase chain reaction (PCR) assay validated and published by the Community Reference Laboratory (CRL). We analysed the nucleotide sequence variation in the target genomic regions in a broad range of transgenic and conventional varieties and lines: MON 810 varieties cultivated in Spain and conventional varieties from various geographical origins and breeding history. In addition, the reliability of the assays was evaluated based on their PCR amplification performance. A single base pair substitution, corresponding to a single nucleotide polymorphism (SNP) reported in an earlier study, was observed in the forward primer of one of the studied alcohol dehydrogenase 1 ( Adh1) (70) assays in a large number of varieties. The SNP presence is consistent with a poor PCR performance observed for this assay along the tested varieties. The obtained data show that the Adh1 (70) assay used in the official CRL NK603 assay is unreliable. Based on our results from both the nucleotide stability study and the PCR performance test, we can conclude that the Adh1 (136) reference assay (T25 and Bt11 assays) as well as the tested high mobility group protein gene assay, which also form parts of CRL methods for quantification, are highly reliable. Despite the observed uniformity in the nucleotide sequence of the invertase gene assay, the PCR performance test reveals that this target sequence might occur in more than one copy. Finally, although currently not forming a part of official quantification methods, zein and SSIIb assays are found to be highly reliable in terms of nucleotide stability and PCR performance and are proposed as good alternative targets for a reference assay for maize. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Since a decade, the large-scale commercial production of Siratia grosvenorii plantlets is being practiced through in vitro culture of its microcuttings, but it has some drawbacks such as handling of plantlets, low transplant-survival rate, development of massive callus, low yield after transplantation, etc. An experiment has been conducted to improve the prevailing technique as well as to develop a new ex vitro technique to overcome these drawbacks. Several concentrations of naphthalene acetic acid (NAA) (0–4.0 mg/l) have been tried with the MS (Murashige and Skoog in Physiol Plant 15:473–479, 1962) basal medium containing 3% (w/v) sucrose and 4.0 g/l agar, out of which 0.1 mg/l NAA was found best in terms of smaller diameter of callus and maximum rooting and transplant survival rate. Further, use of perlite instead of agar medium also showed possibilities for future research on commercial-scale plantlet production. Ex vitro rooting technique was found superior to the in vitro one as plantlets developed through this method had lateral roots without any callus at the base of microcuttings, just like the natural root system and of course with higher root length, rooting rates, and transplant survival rate compared to the in vitro developed plantlets. Further, this technique is economical in terms of labor and time saving and gives rise to vigorous plants which ultimately bring higher yields and profits. [ABSTRACT FROM AUTHOR]

Genetically modified (GM) cotton lines have been approved for commercialization and widely cultivated in many countries, especially in China. As a step towards the development of reliable qualitative and quantitative PCR methods for detecting GM cottons, we report here the validation of the cotton ( Gossypium hirsutum) endogenous reference control gene, Sad1, using conventional and real-time (RT)-PCR methods. Both methods were tested on 15 different G. hirsutum cultivars, and identical amplicons were obtained with all of them. No amplicons were observed when DNA samples from three species of genus Gossypium, Arabidopsis thaliana, maize, and soybean and others were used as amplified templates, demonstrating that these two systems are specific for the identification and quantification of G. hirsutum. The results of Southern blot analysis also showed that the Sad1 gene was two copies in these 15 different G. hirsutum cultivars. Furthermore, one multiplex RT-quantitative PCR employing this gene as an endogenous reference gene was designed to quantify the Cry1A(c) gene modified from Bacillus thuringiensis (Bt) in the insect-resistant cottons, such as Mon531 and GK19. The quantification detection limit of the Cry1A(c) and Sad1 genes was as low as 10 pg of genomic DNA. These results indicat that the Sad1 gene can be used as an endogenous reference gene for both qualitative and quantitative PCR detection of GM cottons. [ABSTRACT FROM AUTHOR]

The CDEX-10 experiment searches for light weakly interacting massive particles, a form of dark matter, at the China Jinping Underground Laboratory, where approximately 10 kg of germanium detectors are arranged in an array and immersed in liquid nitrogen. Herein, we report on the experimental apparatus, detector characterization, and spectrum analysis of one prototype detector. Owing to the higher rise-time resolution of the CDEX-10 prototype detector as compared with CDEX-1B, we identified the origin of an observed category of extremely fast events. For data analysis of the CDEX-10 prototype detector, we introduced and applied an improved bulk/surface event discrimination method. The results of the new method were compared to those of the CDEX-1B spectrum. Both sets of results showed good consistency in the 0-12 keVee energy range, except for the 8.0 keV K-shell X-ray peak from the external copper. [ABSTRACT FROM AUTHOR]

A study on cosmogenic activation in germanium was carried out to evaluate the cosmogenic background level of natural and 70Ge depleted germanium detectors. The production rates of long-lived radionuclides were calculated with Geant4 and CRY. Results were validated by comparing the simulated and experimental spectra of CDEX-1B detector. Based on the validated codes, the cosmogenic background level was predicted for further tonne-scale CDEX experiment. The suppression of cosmogenic background level could be achieved by underground germanium crystal growth and high-purity germanium detector fabrication to reach the sensitivity requirement for direct detection of dark matter. With the low cosmogenic background, new physics channels, such as solar neutrino research and neutrinoless double-beta decay experiments, were opened and the corresponding simulations and evaluations were carried out. [ABSTRACT FROM AUTHOR]