Prototyping is an effective and efficient way of requirement validation to avoid introducing errors in the early stage of software development. Our previous work RM2PT can automatically generate ...prototypes from requirements models to support incremental and rapid requirements validation. Although the stakeholders can validate requirements through executing the system operations of the generated prototype, the input parameters of system operations still need to be manually typed by the stakeholders. Unlike software testing, the input of system operation must be valid and reasonable for the stakeholders under the specific scenario of use case. This is usually hard to be achieved by the stakeholders who have less knowledge and concern about the state and interface of target system. In this paper, we propose a tool named InputGen to automatically refactor and enhance the generated prototype from RM2PT. The enhanced prototype can automatically generate valid input data of the system operations for requirement validation. In addition, the enhanced prototype provide an external interface to load the initial data from an external file, which can save the time of modeling the data functionality for the administrator. We demonstrate that the enhanced prototype can improve requirements validation efficiency by 13.77 times over the originally generated prototype from RM2PT. Overall, the results were satisfactory. The proposed tool can be further extended and applied for the requirements validation in the software industry.
The tool can be downloaded at https://rm2pt.com/advs/inputgen, and a demo video casting its features is at https://youtu.be/iR_ojHyzDvQ
Reducing the dimensionality of transition metal dichalcogenides to one dimension opens it to structural and electronic modulation related to charge density wave and quantum correlation effects ...arising from edge states. The greater flexibility of a molecular scale nanowire allows a strain-imposing substrate to exert structural and electronic modulation on it, leading to an interplay between the curvature-induced influences and intrinsic ground-state topology. Herein, the templated growth of MoS2 nanowire arrays consisting of the smallest stoichiometric MoS2 building blocks is investigated using scanning tunnelling microscopy and non-contact atomic force microscopy. Our results show that lattice strain imposed on a nanowire causes the energy of the edge states to oscillate periodically along its length in phase with the period of the substrate topographical modulation. This periodic oscillation vanishes when individual MoS2 nanowires join to form a wider nanoribbon, revealing that the strain-induced modulation depends on in-plane rigidity, which increases with system size.
•Combined Si- and Ca-based mineral scaling in brackish water RO were probed.•Coexisting silica reduced Ca-based mineral scaling on RO membrane.•Protective silica coatings formed around Ca-based ...mineral precipitates.•Silica coating retarded the morphological evolution of Ca-based mineral species.•The formation mechanisms of silica coatings were revealed.
Although the autopsies of reverse osmosis (RO) membranes from full-scale, brackish water desalination plants identify the co-presence of silica and Ca-based minerals in scaling layers, minimal research exists on their formation process and mechanisms. Therefore, combined scaling by silica and either gypsum (non-alkaline) or amorphous calcium phosphate (ACP, alkaline) was investigated in this study for their distinctive impacts on membrane performance. The obtained results demonstrate that the coexistence of silica and Ca-based mineral salts in feedwaters significantly reduced water flux decline as compared to single type of Ca-based mineral salts. This antagonistic effect was primarily attributed to the silica-mediated alleviation of Ca-based mineral scaling. In the presence of silica, silica skins were immediately established around Ca-based mineral precipitates once they emerged. Sheathing by the siliceous skins hindered the aggregation and thus the morphological evolution of Ca-based mineral species. Unlike sulfate precipitates, ACP precipitates can induce the formation of dense and thick silica skins via an additional condensation reaction. Such a phenomenon rationalized the notion concerning a stronger mitigating effect of silica on ACP scaling than gypsum scaling. Meanwhile, coating by silica skins altered the surface chemistries of Ca-based mineral precipitates, which should be fully considered in regulating membrane surface properties for combined scaling control. Our findings advance the mechanistic understanding on combined mineral scaling of RO membranes, and may guide the appropriate design of membrane surface properties for scaling-resistant membrane tailored to brackish water desalination.
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Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) dissemination within water pose a serious threat to public health. Herein, C and O dual-doped g-C3N4 (C/O-g-C3N4) ...photocatalyst, fabricated via calcination treatment, was utilized to activate peroxydisulfate (PDS) to investigate the disinfection effect on tetracycline-resistant Escherichia coli and the transformation frequency of ARGs. As a result, approximately 7.08 log E. coli were inactivated, and 72.36 % and 53.96 % of antibiotics resistance gene (tetB) and 16 S rRNA were degraded respectively within 80 min. Futhermore, the transformation frequency was reduced to 0.8. Characterization and theoretical results indicated that C and O doping in g-C3N4 might lead to the electronic structure modulation and band gap energy reduction, resulting in the production of more free radicals. The mechanism analysis revealed that C/O-g-C3N4 exhibited a lower adsorption energy and reaction energy barrier for PDS compared to g-C3N4. This was beneficial for the homolysis of O-O bonds, forming SO4•- radicals. The attack of the generated active species led to oxidative stress in cells, resulting in damage to the electron transport chain and inhibition of ATP production. Our findings disclose a valuable insight for inactivating ARB, and provide a prospective strategy for ARGs dissemination in water contamination.
Hierarchically porous magnetic biochar (HMB) had been found to act as an effective amendment to remediate cadmium (Cd) in water and soil in a previous study, but the effects on wheat growth, Cd ...uptake and translocation mechanisms, and soil microorganisms were unknown. Therefore, soil Cd form transformation, soil enzyme activity, soil microbial diversity, wheat Cd uptake and migration, and wheat growth were explored by adding different amounts of HMB to alkaline Cd-contaminated soil under pot experiments. The results showed that application of HMB (0.5 %–2.0 %) raised soil pH, electrical conductivity (EC) and available Fe concentration, decreased soil available Cd concentration (35.11 %–50.91 %), and promoted Cd conversion to less bioavailable Cd forms. HMB treatments could reduce Cd enrichment in wheat, inhibit Cd migration from root to stem, rachis to glume, glume to grain, and promote Cd migration from stem to leaf and stem to rachis. HMB (0.5 %–1.0 %) boosted antioxidant enzyme activity, reduced oxidative stress, and enhanced photosynthesis in wheat seedlings. Application of 1.0 % HMB increased wheat grain biomass by 40.32 %. Besides, the addition of HMB (0.5 %–1.0 %) could reduce soil Cd bioavailability, increase soil enzyme activity, and increase the abundance and diversity of soil bacteria. Higher soil EC brought forth by HMB (2.0 %) made the wheat plants and soil bacteria poisonous. This study suggests that applying the right amount of HMB to alkaline Cd-contaminated soil could be a potential remediation strategy to decrease Cd in plants' edible parts and enhance soil quality.
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•HMB facilitated the rapid conversion of Cd in soil to less bioavailable Cd forms.•HMB could promote Cd migration from stem to leaf and stem to rachis.•HMB could effectively reduce Cd uptake and translocation to wheat grains.•Moderate HMB could positively affect bacterial species diversity and abundance.•Moderate HMB could alleviate the wheat Cd-induced oxidative damage.
Background
Chemokine receptors are now known to play an important role in cancer growth and metastasis. However, there is little information regarding chemokine expression in gastric cancer. In this ...study, we examined CXCL12 expression in gastric cancer and also evaluated whether the down-regulation of CXCL12 is due to aberrant methylation of the gene.
Methods
CXCL12 expression was examined using real-time reverse-transcription polymerase chain reaction (RT-PCR), immunofluorescence, flow cytometry, and immunohistochemistry, and the methylation status of the gene was evaluated by methylation-specific PCR (MSP) in normal gastric and gastric cancer cell lines and 35 primary gastric carcinomas and corresponding nonmalignant gastric tissues.
Results
The down-regulation of CXCL12 was observed in gastric cancer cell lines and primary gastric carcinomas, while decreased expression of CXCL12 protein was significantly associated with lymph node metastasis and histological grade. And this down-regulation was found to be in accordance with aberrant methylation of the gene. Hypermethylation of the gene was observed in 65.7% (23 of 35) of the primary gastric carcinomas, while it was found in only 11.4% (4/35) of the corresponding nonmalignant tissues. Furthermore, CXCL12 expression was restored in gastric cancer cell lines after treatment with the demethylating agent, 5-aza-2′-deoxycytidine (5-Aza-dC), and demethylation of the highly metastatic cells SGC-7901 induced invasion suppression of the cells. For two CXCL12 receptors, CXCR4 and CXCR7, the mRNA levels remained almost unchanged with the 5-Aza-dC treatment.
Conclusions
Collectively, our results suggest that the aberrant methylation of CXCL12 frequently occurs in the down-regulation of CXCL12 in gastric cancers and that it may play a role in the metastasis of gastric cancer.
The purpose of this study is to detect the clinical significance of NDRG1 and its relationship with MMP-9 in gastric cancer metastatic progression. 101 cases of gastric cancer specimens were utilized ...to identify the protein expression of NDRG1 and MMP-9 by immunohistochemistry, their clinical significance was also analyzed. The suppression by siRNA-NDRG1 was employed to detect the role of NDRG1 in gastric cancer progression and its relationship with MMP-9. NDRG1 expression was correlated inversely with the degree of tumor cell differentiation (
p
< 0.01), invasion depth (
p
< 0.05), lymph node metastasis (
p
< 0.05) and TNM stage (
p
< 0.05), whereas MMP-9 was positive correlated with the degree of tumor cell differentiation (
p
< 0.01), lymph node metastasis (
p
< 0.05) and TNM stage (
p
< 0.05), but not correlated with invasion depth (
p
>0.05). Furthermore, cell proliferation and invasion effect were remarkably enhanced when NDRG1 was silencing, but MMP-9 expression was increased. NDRG1 silencing enhances gastric cancer cells progression through upregulating MMP-9. It suggests that NDRG1 may inhibit the metastasis of gastric cancer via regulating MMP-9.
Background
Gastric cancer is one of the most common digestive malignancies worldwide. N-myc downstream-regulated gene 2 (NDRG2) is a differentiation-related gene that is considered to be a metastasis ...suppressor gene. In this study, we examined the expression and DNA methylation of NDRG2 in gastric cancer cell lines and tissues, as well as its clinical significance.
Methods
Six gastric cancer cell lines and 42 paired normal and gastric cancer tissue samples were used to assess NDRG2 mRNA expression using RT-PCR. NDRG2 DNA methylation status was evaluated by methylation-specific PCR (MSP) in gastric cancer cell lines and tissues. The suppression of NDRG2 in BGC823 cells by siRNA transfection was utilized to detect the role of NDRG2 in gastric cancer progression.
Results
NDRG2 mRNA was down-regulated in gastric cancer cell lines and tissues, and its expression was just related to lymph node metastasis (
p
= 0.032). MSP showed methylation of NDRG2 in 54.0 % (47/87) of primary gastric cancer specimens and in 20.0 % (16/80) of corresponding nonmalignant gastric tissues. NDRG2 methylation was related to depth of tumor invasion, Borrmann classification and TNM stage (
p
< 0.05). Upon treatment with 5-aza-2′-deoxycytidine and trichostatin A, NDRG2 expression was upregulated in HGC27 cells, and demethylation of the highly metastatic cell line, MKN45, inhibited cell invasion. Furthermore, the suppression of NDRG2 by siRNA transfection enhanced BGC823 cells invasion.
Conclusions
Our results suggest that the aberrant methylation of NDRG2 may be mainly responsible for its downregulation in gastric cancer, and may play an important role in the metastasis of gastric cancer.
N-myc downstream-regulated gene 1 (NDRG1) has been proposed as a tumor suppressor gene in many different types of tumors, but its potential function and corresponding mechanism are not yet fully ...elucidated. This study aims to detect the possible function of NDRG1 in gastric cancer progression. In this study, 112 paired gastric cancer tissues and corresponding nonmalignant gastric tissues were utilized to identify the differential protein expression of NDRG1 by immunohistochemistry and its clinical significance was analyzed. Furthermore, 49 of 112 paired gastric specimens were used to detect the differential mRNA expression by real-time PCR. The over expression of NDRG1 in human gastric cancer cell line AGS by PcDNA3.1–NDRG1 transfection was utilized to detect the role of NDRG1 in regulating the biological behavior of gastric cancer. NDRG1 expression was significantly decreased in primary gastric cancer tissues, compared with its corresponding nonmalignant gastric tissues (p < 0.05), and its decreased expression was significantly associated with lymph node metastasis (p < 0.01), invasion depth (p < 0.01) and differentiation (p < 0.05). Additionally, the overall survival rate of gastric cancer patients with high expression of NDRG1 was higher than those with low expression during the follow-up period. NDRG1 overexpression suppressed cells proliferation, invasion and induced a G1 cell cycle arrest in gastric cancer. Furthermore, the down-regulation of NDRG1 in gastric cancer metastatic progression was correlated to E-cadherin and MMP-9. Our results verify that NDRG1 acts as a tumor suppressor gene and may play an important role in the metastasis progression and prognosis of gastric cancer.
Abstract Many studies have analyzed the relation about xeroderma pigmentosum group D (XPD) Lys751Gln polymorphism on esophageal cancer risk; however, the results were inconclusive. The present study ...was designed to assess the relationship in China. We searched the relevant articles from the databases of PubMed, Springer Link, Ovid, Chinese Wanfang Database, CNKI and Chinese Biology Medicine up to December 2019. An OR with the corresponding 95%CI was adopted to evaluate this association. This meta-analysis included 12 studies with 4195 esophageal cancer cases and 4762 controls. Overall, a positive association between XPD Lys751Gln and esophageal cancer risk was found in all the analysis model (Gln vs. Lys, OR= 1.26, 95% CI= 1.14-1.44; Gln/Gln vs. Lys/Lys, OR= 1.73, 95% CI= 1.29-2.31; Gln/Gln vs. Lys/Lys + Asp/Asn, OR= 1.63, 95% CI= 1.22-2.18; Gln/Gln+ Asp/Asn vs. Lys/Lys, OR= 1.25, 95% CI= 1.13-1.39). Subgroup analyses by geographic area and source of controls were further conducted; there was no substantial change in subgroup analyses. Our study suggested that XPD Lys751Gln polymorphism could increase the risk of esophageal cancer in China. Further studies in other ethnic populations are wanted to confirm these conclusions.
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