Search

Copyright of Geostandards & Geoanalytical Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highly sensitive real-time pyrosequencing seems promising for constructing an inexpensive and small DNA sequencer with a low running cost. A DNA sample of a picomole level is usually used in the conventional pyrosequencing based on a luciferase assay coupled with an APS-ATP surfurylase reaction for producing ATP from pyrophosphate (PPi). Although the luminescence intensity could be increased by increasing the amount of luciferase, it was impossible to reduce the target DNA amount because of a large background luminescence due to the luciferase-APS reaction. In this report, a novel approach using a new conversion reaction of PPi to ATP is proposed. This method has a very low background and can produce high signals in the presence of a large amount of luciferase; thus, the sample amount required for sequencing is significantly reduced. The ATP production from PPi is catalyzed with pyruvate orthophosphate dikinase (PPDK) using AMP and phosphoenolpyruvate as the substrates, which are inactive for the luciferase-catalyzed reaction. All of the components in the AMP-PPDK-based pyrosequencing system are suitable for highly sensitive DNA sequencing in one tube. Real-time DNA sequencing with a readable length up to 70 bases was successfully demonstrated by using this system. By increasing the amount of luciferase, as low as 2.5 fmol of DNA templates was accurately sequenced by the proposed method with a novel simple and inexpensive DNA sequencer having a photodiode array as a sensor instead of a PMT or CCD camera. A sample amount as low as 2 orders of magnitude smaller than that used in the conventional pyrosequencer can be used. [ABSTRACT FROM AUTHOR]

• Agricultural product supply chain. • Information sharing. • Fuzzy big data and LSGDM. Information asymmetry is the root of agricultural product quality problems. Generally speaking, the common problems related to agricultural products are solved by effective supply chain management. From the perspective of agricultural supply chain management, this paper analyzes the shortcomings of the traditional supply chain management process by using fuzzy big data and LSGDM (Large scale group decision making), and puts forward a new method of supply chain management. In addition, from the perspective of asymmetric information sharing regarding agricultural products, an asymmetric information sharing model for agricultural products based on the evolutionary rule theory is established. Combined with fuzzy big data and LSGDM, this paper puts forward the hypothesis of each variable in the process of the information sharing game. On this basis, a mathematical model of the "pool equilibrium" of the high and low prices in the agricultural products market is put forward. Finally, a case study of products of different quality in the sea cucumber market is carried out. The results show that high quality sea cucumber products occupy a large market share in the supply chain of agricultural products. The research of this paper is of great significance, because it can increase the reliable theoretical data available for the research of the agricultural supply chain. [ABSTRACT FROM AUTHOR]

A new molecular beacon (MB) driven by two-photon excitation (TPE) using quantum dots as energy donor is constructed, which provides reduced direct excitation of acceptor and is free of interferences from autofluorescence or scattering light in a complicated biological matrix. [ABSTRACT FROM AUTHOR]

In order to detect small amounts of mutants for early cancer diagnosis, we have developed the novel method of using amplicon-coated microbeads and single-molecule-PCR in water-in-oil emulsions, which we coupled with a new detection platform, the hydrogel bead-array, a 3-D polyacrylamide gel network used as a carrier to immobilize the beads. [ABSTRACT FROM AUTHOR]

Power factor correction (PFC) converter with a twice-line-frequency ripple cancellation converter (RCC) has attracted much attention due to its ability of twice-line-frequency output voltage ripple cancellation and high power conversion efficiency. The audio susceptibility of buck-type RCC operating in discontinuous conduction mode is derived and the effect of loop gain of RCC on the cancellation of twice-line-frequency output voltage ripple is studied. Experimental results of a 50 W prototype are presented to verify the analysis results. [ABSTRACT FROM AUTHOR]

Objective To evaluate clinical efficacy of the combination of Vonoprazan and high-dose Amoxicillin in the initial eradication treatment of Helicobacter pylori （Hp）. Methods Select 200 patients with Hp infection who have not undergone Hp eradication treatment in the past as the research subjects. All patients were randomly divided into the observation group （n = 100） and control group （n = 100） using random number table method. In the observation group， a combination regimen of Vonoprazan （20 mg twice a day） and Amoxicillin （1 g three times a day） was given for 14 days. In the control group， a bismuth quadruple therapy was delivered for 14 days， which included Esomeprazole （20 mg twice a day）， Bismuth Potassium Citrate （220 mg twice a day）， Amoxicillin （1 g twice a day） and Clarithromycin （0.5 g twice a day）. The Hp eradication rate and incidence of adverse reactions after medication were compared between two groups. Results Of 200 patients， 11 patients were excluded from subsequent analysis， including 8 cases lost to follow-up and 3 cases with poor compliance of medication. The remaining 189 patients （96 in the observation group and 93 in the control group） completed the entire procedure. According to intention-to-treat （ITT） and per-protocol （PP） set analyses， the Hp eradication rate in the observation group was significantly higher than that in the control group （91.0% vs. 79.0%， PITT =0.017； 94.8% vs. 84.9%， PPP= 0.024）. The incidence of adverse reactions did not significantly differ between two groups （4% vs. 5%，χ 2 < 0.001，P > 0.999）. Conclusion The combination therapy of Vonoprazan and high-dose Amoxicillin is an efficacious and safe therapeutic option for patients with initial Hp infection， which is worthy of promotion in grassroot-level hospitals.

Based on soft-switched continuous conduction mode boost converter, a zero-voltage zero-current switching DC/DC converter is proposed by introducing a flyback-unit and a voltage-double-unit. The proposed converter can achieve high voltage gain without operating at extreme high duty cycle. Moreover, by replacing the output diode of conventional boost converter with an active switch, zero-voltage-switched turn-on of switches and zero-current-switched turn-off of diodes can be achieved, which reduce switching loss and alleviate reverse-recovery problem of diodes. Furthermore, the energy in leakage inductor can be transferred into the output of the converter to improve the efficiency. The operating characteristics and the voltage gain of the proposed converter are analysed. Experimental results of a 100 W prototype are provided to verify the theoretical analysis results. [ABSTRACT FROM AUTHOR]

There are two weaknesses in conventional constant off-time controlled buck-type DC-DC converters: which are varied switching frequency and poor output-regulation accuracy. To make the switching frequency immune to the variation of the input voltage and the reference voltage and provide both high output-regulation accuracy and a fast transient response for buck-type DC-DC converters, a new control method, called the quasi-constant-frequency variable off-time control technique, is proposed. Circuit simulation results validate the correctness of the theoretical analysis. [ABSTRACT FROM AUTHOR]

Constant on-time (COT) control has been widely applied in industrial applications due to its fast transient response. However, the conventional COT controlled buck converter has poor output-regulation accuracy. A new control method, called improved COT (ICOT) control, that provides both high output-regulation accuracy and fast transient response for the buck converter is proposed. Circuit simulation results validate the correctness of the theoretical analysis. [ABSTRACT FROM AUTHOR]

A flicker-free transformerless light emitting diode (LED) driving circuit based on a quadratic buck power factor correction (PFC) converter is proposed. It combines a cascaded input buck PFC converter and an output buck dc-dc converter with a single switch. The proposed LED driving circuit can not only achieve high PFC to comply with the EN61000-3-2 standard and low output voltage without a high stepdown transformer, but also reduces second-order line frequency current ripple flowing through the LED to eliminate light flicker of the LED. Experimental results of a 7 W prototype are presented to verify the analysis results of the proposed converter. [ABSTRACT FROM AUTHOR]

It has been reported that subharmonic instability exists in the V² controlled buck converter in continuous conduction mode (CCM) when the duty ratio is above 0.5 (D > 0.5) and no stability issue exists in discontinuous conduction mode (DCM) when 0 < D < 1. However, the CCM and DCM instabilities will appear in the safe duty ratio range when the equivalent series resistance (ESR) of the output capacitor is below a critical value. The critical output-capacitor ESR for the stabiiity of a V² controlled buck converter in CCM and DCM is investigated by using the discrete-time model and verified by circuit simulations. [ABSTRACT FROM AUTHOR]

It is 18 years since the V² control was proposed in 1996. Many publications have shown that the V² controlled switching converter exhibits an ultra-fast load transient response. Recently, it has been reported that the conventional V² control is inherently a peak V² control, based on which V² control can be classified as peak V² and valley V² controls. However, till now the switching converter with V² control is almost a buck converter. This leads to the investigation of whether the V² control can be applied to a boost converter. [ABSTRACT FROM AUTHOR]

Compared with a pulse-width modulated voltage-mode controlled switching converter, a constant on-time (COT) controlled switching converter has extensive industry application due to its fast transient response. However, the conventional COT controlled switching converter has poor output-regulation accuracy. A new control method that provides both fast transient response and high output-regulation accuracy for switching converters, called dual COT control, is proposed. The analysis results are verified by circuit simulation. [ABSTRACT FROM AUTHOR]

Triple negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer that poses a clinical challenge. Thus, new therapy strategies are urgently needed. The selective WEE1 inhibitor, AZD1775, has shown strong anti-proliferative effects on a variety of tumors. Here, we first demonstrate that inhibition of ATR by selective inhibitor AZD6738 can enhance AZD1775-caused growth inhibition in TNBC. Our results show that the enhanced cell death is attributed to repressed DNA damage repair and excessive replication stress, thereby causing increased DNA damage reflected by accumulation of the DNA double-strand-break marker γH2AX. On the other hand, combined treatment with AZD6738 and AZD1775 forces mitotic entry of cells with DNA damages by activating CDK1 activity, inducing severely aberrant mitosis and mitotic catastrophe, ultimately resulting in cell death. Dual inhibition of WEE1 and ATR also inactivated RAD51-mediated homologous recombination, which sensitized TNBC cells to cisplatin and PARP inhibitor. Here, based on the preclinical results that ATR inhibition synergizes with WEE1 inhibition in TNBC, we propose that this combination therapy alone, or in parallel with chemotherapy, represents an innovative and potent targeted therapy in TNBC. [ABSTRACT FROM AUTHOR]

Grain shape of rice is an important trait for both yield and quality. A rice rk4 (round kernel) mutant was obtained from the japonica variety Zhonghua 11 by radiation of 60Co-γ. The grain width of the mutant was increased and the length was decreased. Simultaneously, the 1000-grain weight was slightly reduced, therefore the grain shape of the mutant tended to be small and round. In this study, genetic analysis and gene mapping of the mutant gene were carried out using the F2 and F3 populations derived from the mutant and the indica variety Xianhui 8006. The results suggested that the round kernel was controlled by a single recessive allele (rk4) which was located on chromosome 5. The RK4 gene was further mapped between the molecular markers LSTS5-77 and LSTS5-60 with 0.57 and 0.096 cM, respectively. A BAC clone was found to span the RK4 locus, and the RK4 gene was placed in a 46 kb region that contains six annotated genes according to the available sequence annotation database. This result will help us to isolate the RK4 gene and reveal the molecular mechanism of the round kernel in rice. [ABSTRACT FROM AUTHOR]

Herein, a one-tube colorimetric platform has been developed for the simultaneous determination of two analytes (DNA as model object) in one tube with picomolar sensitivity. SPR-active nanoparticles are used to encode reporter probes sensitive to oligonucleotides associated with hepatitis A virus Vall7 polyprotein gene (HVA) and hepatitis B virus surface-antigen gene (HVB) respectively and magnetic beads (MBs) serve as the removal tool. In this mixed nanoparticles based biosensor, the addition of target analytes could change the concentration of each nanoparticle, leading to different colors of the supernatant. The influence of spectral overlap has been eliminated by a non-negative matrix factorization (NMF). With the assistance of NMF, the limit of detection (LOD) can be determinated as pM level without amplification. On the whole, this nanosensor boasts the advantages of high sensitivity and low sample consumption. Simultaneous colorimetric detection and quantification of two molecules in one tube are demonstrated. [ABSTRACT FROM AUTHOR]

We have developed a new fluorescent immune ensemble probe comprised of a conjugated lower toxic water-soluble CdTe:Zn2+ quantum dots (QDs) and Ru(bpy)2(mcbpy-O-Su-ester)(PF6)2-antibody complex (Ru-Ab) for the dual-color determination of human enterovirus 71 (EV71) in homogeneous solution. EV71 monoantibody was easily covalently conjugated with Ru(bpy)2 (mcbpy-O-Su-ester)(PF6)2 to form a stable complex Ru-Ab, which acted both as an effective quencher of QDs fluorescence and the capture probe of virus antigen EV71. Herein, the target EV71 can break up the low fluorescent ionic ensemble by antigen-antibody combination to set free the fluorescent QDs and restore the fluorescence of QDs whereas the fluorescence intensity of Ru-Ab remains the same. Thus, the determination of EV71 by the complex Ru-Ab and QDs can be realized via the restoration of QDs fluorescence upon addition of EV71 and even can be directly evaluated by the ratio of green-colored QDs fluorescence intensity to Ru-Ab red-colored fluorescence intensity. The green-colored fluorescence of QDs was very sensitive to the change of EV71 concentration, and its fluorescence intensity increased with the increase of EV71 concentration between 1.8 ng/mL and 12 μg/mL. With this method, EV71 was detected at subnanogram per milliliter concentration in the presence of 160 μg/mL bovine serum albumin. More importantly, this strategy can be used as a universal method for any protein or virus by changing conjugated antibodies in disease early diagnosis providing a fast and promising clinical approach for virus determination. In a word, a simple, fast, sensitive, and highly selective assay for EV71 has been described. It could be applied in real sample analysis with a satisfactory result. It was notable that the sensor could not only achieve rapid and precise quantitative determination of protein/virus by fluorescent intensity but also could be applied in semiquantitative protein/virus determination by digital visualization. [ABSTRACT FROM AUTHOR]

Toll-like receptor 3 (TLR3), a member of the pathogen recognition receptors, is widely expressed in various cells and has been shown to activate immune signaling pathways by recognizing viral double-stranded RNA. Recently, it was reported that the activation of TLR3 induced apoptosis in some cells, but the detailed molecular mechanism is not fully understood. In this study, we found that in endothelial cells polyinosinic-polycytidylic acid (poly(I-C)) induced dose- and time-dependent cell apoptosis, which was elicited by TLR3 activation, as TLR3 neutralization and down-regulation repressed the apoptosis. Poly(I-C) induced the activation of both caspases 8 and 9, indicating that TLR3 triggered the signaling of both the extrinsic and intrinsic apoptotic pathways. Poly(I-C) up-regulated tumor necrosis factor-related apoptosis-inducing ligand and its receptors, death receptors 4/5, resulting in initiating the extrinsic pathway. Furthermore, poly(I-C) down-regulated anti-apoptotic protein, B cell lymphoma 2 (Bcl-2), and up-regulated Noxa, a key Bcl-2 homology 3-only antagonist of Bcl-2, leading to the priming of the intrinsic pathway. A p53-related protein, the transactivating p63 isoform α (TAp63α), was induced by TLR3 activation and contributed to the activation of both the intrinsic and extrinsic apoptotic pathways. Both the cells deficient in p63 gene expression by RNA interference and cells that overexpressed the N-terminally truncated p63 isoform α (ΔNp63α), a dominant-negative variant of TAp63α, by gene transfection, survived TLR3 activation. Taken together, TAp63α is a crucial regulator downstream of TLR3 to induce cell death via death receptors and mitochondria. [ABSTRACT FROM AUTHOR]

A novel DNA detection assay was proposed by invasive reaction coupled with molecular beacon assisted strand-displacement signal amplification (IRASA). Target DNAs are firstly hybridized to two probes to initiate invasive reaction to produce amplified flaps. Then these flaps are further amplified by strand-displacement signal amplification. The detection limit was around 0.2 pM. [ABSTRACT FROM AUTHOR]

China's rural reform is reliant on farmers' cooperatives as a key organization vehicle. It plays an important role in promoting rural revitalization. Such as, realizing the organic connection between small farmers and agricultural modernization. This study used the nearest neighbor index and kernel density estimation to analyze the spatial distribution and structural characteristics of farmer cooperatives in Hunan Province. It revealed the spatial differentiation law of cooperatives. Also using geographical detectors to figure out the main factors that affect the spatial distribution. The results show that: ① Hunan Farmers Cooperatives show significant spatial agglomeration. The overall spatial distribution shows the spatial characteristics of "one core, one circle, and multiple points". And the spatial distribution pattern of "large agglomeration, finger-shaped radiation distribution". Among them, the distribution of provincial demonstration cooperatives is relatively balanced. ② Cooperatives in six types of industries, such as planting, forestry, and feeding, showed agglomeration distribution. Different industrial cooperatives spread out in different ways, such as in an anti-"L" shape, a dual-core shape, or a one-center area. ③ The 24 influence factors selected from the five dimensions of the natural environment, social economic basis, production basis, output capacity, and facility basis have high, general, and weak influence on cooperatives' spatial distribution. The development and distribution of cooperatives mainly depend on resource endowment, social and economic development level, and market dependence. The spatial distribution heterogeneity of different professional cooperatives is mainly affected by slope, per capita disposable income of rural residents, road density, and other factors. ④ The progression of farmer cooperatives in Hunan Province should prioritize high-quality development, emphasizing the need for innovative approaches and transformative strategies within rural industrial organizations. It is imperative to optimize the spatial distribution of cooperatives, strategically contributing to the establishment of a novel framework for modern agricultural development in Hunan Province. Additionally, there is a critical emphasis on spearheading collaborative initiatives among cooperatives of varied industrial types, aimed at fostering the integrated development of rural primary, secondary, and tertiary industries., (© 2024. The Author(s).)