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The rings whose every element is uniquely clean are completely characterized in Nicholson and Zhou (Glasg Math J 46(2):227–236, 2004). These rings belong to a larger class of rings for which every clean element is uniquely clean. The latter is the topic of this article. [ABSTRACT FROM AUTHOR]

Green merger and acquisition (GMA) is becoming a growing tendency for heavily polluting enterprises in recent years; however, the realization path of green transformation through GMA is still unexplored. Taking 48 Chinese heavily polluting enterprises that had GMA in 2018 as the research object, this paper constructs the "M&A attributes, Organizational characteristics, and External environment" (M-O-E) framework, by using the method of fuzzy-set qualitative comparative analysis (fsQCA) to reveal the configurations of conditions that lead to high levels of green innovation performance. The results show that the high green technology innovation performance after GMA of heavily polluting enterprises is the outcome of multiple antecedents, and no singular antecedent is sufficient for achieving it. Besides, there are three equivalent configurations of conditions to achieve green transformation: professional buyer, internal leading, and internal-external linkage. Among them, the professional buyer configuration highlights that the combination of M&A experience and M&A scale is of great importance, the internal leading configuration emphasizes that the existence of environmental awareness and organizational resources is the core conditions, and the internal-external linkage configuration requires simultaneous efforts of M&A experience and government environmental regulations. Our research contributes to the understanding of green transformation in heavily polluting enterprises from a configurational perspective, and provides a practice-oriented guide to achieve green transformation for the government and heavily polluting enterprises. [ABSTRACT FROM AUTHOR]

A nonzero sum of a unit and a nilpotent element in a ring is called a fine element. This is a study of rings in which every nonzero nilpotent is fine, which we call NF rings. [ABSTRACT FROM AUTHOR]

Recall that a ring satisfies the 2-sum property if each of its elements is a sum of two units. Here a ring R is said to satisfy the binary 2-sum property if, for any a, b in R, there exists a unit u of R such that both a - u and b - u are units. A well-known result, due to Goldsmith, Pabst and Scot, states that a semilocal ring satisfies the 2-sum property iff it has no image isomorphic to Z 2 . It is proved here that a semilocal ring satisfies the binary 2-sum property iff it has no image isomorphic to Z 2 or Z 3 or M 2 (Z 2) . [ABSTRACT FROM AUTHOR]

A large volume (more than 4.0 million m3) of treated construction and demolition waste (CDW) is planned to be used in the construction of the Xi'an-Xianyang north loop line freeway in West China. These CDW were preliminarily separated into broken concretes, bricks, and porcelains in the treatment plants. In this study, a total of 190 CDW samples including 80 concretes, 80 bricks, 20 porcelains, and 10 mixed samples were collected from five treatment plants. Five farmland soil samples near treatment plants were collected as controls. The contents of 10 elements including cadmium (Cd), arsenic (As), copper (Cu), nickel (Ni), zinc (Zn), chromium (Cr), lead (Pb), manganese (Mn), silver (Ag), and mercury (Hg) in these samples were measured. The contents of 8 elements (Cu, Ni, Zn, Cr, Pb, Mn, Ag, and Hg) in all CDW samples were qualified for the third-level criterion of the Standard of Soil Environment (GB15618-2008). However, Cd contents in 37 concretes, 34 bricks, 6 porcelain samples, and 4 mixed CDW samples exceeded the national third-level standards (1 mg/kg) in GB15618-2008. And As contents in 28 concretes, 21 bricks, 5 porcelain samples, and 3 mixed CDW samples were higher than the national third-level standards (40 mg/kg). The total exceeding standard rates (ESRs) of Cd and As were 42.6% and 30%, respectively. The leaching tests for Cd and As were also done due to their higher ESRs. The results showed that the release amounts (μg/kg) of Cd and As from CDW were increased with increasing liquid to solid ratio (0.4–10 l/kg) but decreased with increasing pH (4–7). The leached concentrations of Cd and As from four types of CDW samples were both in a descending order: brick, mixed materials, concrete, and porcelain. The measured concentrations (μg/L) of Cd and As in leachate were all lower than second-grade criteria of Standard for Groundwater Quality (GB3838-2002). By comparing the leached concentrations of Cd and As with the value in European criteria (EU Council Decision 2003/33/EC) for hazardous wastes, all the CDW samples should be classified as inert or non-hazardous wastes. Thus, it could be concluded that heavy metals in these CDW would not pollute surrounding soil, surface water, and groundwater environment when applied in freeway construction. [ABSTRACT FROM AUTHOR]

Chordoma, a malignant bone cancer, is highly resistant to conventional therapeutic approaches; this greatly limits radio- and chemotherapeutic options and disease management. In the present study, we investigated three patient-derived chordoma cell lines to elucidate the molecular mechanism of resistance to therapeutics. An in vitro high-throughput chemical screening assay and an in vivo xenograft model were used to identify novel chemosensitizers for chordoma. We found that patient-derived chordoma cell lines recapitulated disease phenotypes, which were highlighted by robust resistance to medical therapy manifested as lack of DNA damage accumulation. Mechanistically, the PARP DNA repair pathway was found to play a central role in this resistance. Chemical screening confirmed that PARP inhibitors could strikingly enhance temozolomide (TMZ) therapy in chordoma cells. Combining the FDA-approved PARP inhibitor, olaparib, with chemotherapeutics not only potentiated DNA damage accumulation, cell cycle arrest, and apoptosis in vitro but also suppressed chordoma xenograft expansion in vivo. We conclude that combining PARP inhibition with TMZ could be an effective therapeutic approach for the clinical management of chordoma. Key messages: The PARP DNA repair pathway enhances chemoresistance in chordoma cells. Combining PARP inhibitors with genotoxic agents induces chordoma cell cytotoxicity. PARP inhibitor combining with temozolomide suppresses growth of chordoma in vivo. [ABSTRACT FROM AUTHOR]

An element in a ring is clean (or, unit-regular) if it is the sum (or, the product) of an idempotent and a unit, and is nil-clean if it is the sum of an idempotent and a nilpotent. Firstly, we show that Jacobson's lemma does not hold for nil-clean elements in a ring, answering a question posed by Koşan, Wang and Zhou (2016). Secondly, we present new counter-examples to Diesl's question whether a nil-clean element is clean in a ring. Lastly, we give new examples of unit-regular elements that are not clean in a ring. The rings under consideration in our examples are particular subrings of . [ABSTRACT FROM AUTHOR]

Purpose: The development of glioma therapy in clinical practice (e.g., gene therapy) calls for efficiently visualizing and tracking glioma cells in vivo. Human ferritin heavy chain is a novel gene reporter in magnetic resonance imaging. This study proposes hFTH as a reporter gene for MR molecular imaging in glioma xenografts. Methods: Rat C6 glioma cells were infected by packaged lentivirus carrying hFTH and EGFP genes and obtained by fluorescence-activated cell sorting. The iron-loaded ability was analyzed by the total iron reagent kit. Glioma nude mouse models were established subcutaneously and intracranially. Then, in vivo tumor bioluminescence was performed via the IVIS spectrum imaging system. The MR imaging analysis was analyzed on a 7T animal MRI scanner. Finally, the expression of hFTH was analyzed by western blotting and histological analysis. Results: Stable glioma cells carrying hFTH and EGFP reporter genes were successfully obtained. The intracellular iron concentration was increased without impairing the cell proliferation rate. Glioma cells overexpressing hFTH showed significantly decreased signal intensity on T-weighted MRI both in vitro and in vivo. EGFP fluorescent imaging could also be detected in the subcutaneous and intracranial glioma xenografts. Moreover, the expression of the transferritin receptor was significantly increased in glioma cells carrying the hFTH reporter gene. Conclusion: Our study illustrated that hFTH generated cellular MR imaging contrast efficiently in glioma via regulating the expression of transferritin receptor. This might be a useful reporter gene in cell tracking and MR molecular imaging for glioma diagnosis, gene therapy and tumor metastasis. [ABSTRACT FROM AUTHOR]

Purpose: Fatty acids (FAs) are essential for membrane lipids biosynthesis and energy consumption in cancer cells. De novo FAs synthesis is catalyzed by fatty acid synthase (FASN), which is overexpressed and correlates with histological grade in glioma. Herein, we focused on the role of FASN in glioma neovascularization. Methods: The expression levels of FASN, Ki67 and CD34 were determined using immunohistochemistry (IHC). FASN specific-targeted shRNA and C75 were applied to evaluate the influence of FASN on glioma stem cell proliferation, migration and tube formation ability in vitro. An intracranial glioma model was established to study the effects of FASN on tumor growth and neovascularization in vivo. Results: IHC staining showed that the expression level of FASN correlated with tumor grade, Ki67 levels and microvessels density (MVD) in human gliomas. Inhibition of FASN using shRNAs or C75 decreased tumor growth, prolonged the overall survival of xenograft mice and decreased MVD in brain tumor sections. Moreover, inhibition of FASN blocked hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor A (VEGF-A) signaling and upregulated the anti-angiogenic isoform-VEGFb. Conclusion: Our results suggest that FASN plays a pivotal role in glioma neovascularization, and inhibition of FASN may be a potential target for anti-angiogenic therapy for glioma. [ABSTRACT FROM AUTHOR]

We obtain the structure of the rings in which every element is either a sum or a difference of a nilpotent and an idempotent that commute. This extends the structure theorems of a commutative weakly nil-clean ring, of an abelian weakly nil-clean ring, and of a strongly nil-clean ring. As applications, this result is used to determine the 2-primal rings R such that the matrix ring $$\mathbb{M}_n (R)$$ is weakly nil-clean, and to show that the endomorphism ring End( V) over a vector space V is weakly nil-clean if and only if it is nil-clean or dim( V) = 1 with D≅= ℤ. [ABSTRACT FROM AUTHOR]

Let M be a right module over a ring R and let G be a group. The set MG of all formal finite sums of the form ∑ m g where m ∈ M becomes a right module over the group ring RG under addition and scalar multiplication similar to the addition and multiplication of a group ring. In this paper, we study basic properties of the RG-module MG, and characterize module properties of ( MG) in terms of properties of M and G. Particularly, we prove the module-theoretic versions of several well-known results on group rings, including Maschke's Theorem and the classical characterizations of right self-injective group rings and of von Neumann regular group rings. [ABSTRACT FROM AUTHOR]

Purpose: The herpes simplex virus type 1 tegument protein VP22 has the remarkable property of intercellular trafficking, thus making it a promising tool for improving gene transfer efficiency. Methods: To investigate whether the fusion of VP22 to the cytosine deaminase (CD) suicide gene could enhance the therapeutic efficiency of neural stem cells (NSCs) in the treatment for C6 glioma, the lentiviral vectors pHIV-VP-EGFP, pHIV-CD, and pHIV-VP-CD were constructed based on the pHIV-EGFP vector. After packaging, vectors were transduced into rat NSCs. Results: Fluorescence-activated cell sorting analysis revealed that the fusion of VP22-EGFP increased the expression rate of EGFP in NSCs compared with lenti-EGFP transduced cells. Under incubation with the prodrug 5-fluorocytosine (5-FC), the survival rates of C6 cells co-cultured with NSCs/VP-CD (NSCs transduced with lenti-VP-CD) decreased tremendously compared with those of C6 and NSCs/CD. Similar results were also observed in vivo; a significant reduction in tumor volumes in C6 glioma-bearing rats was observed in the NSCs/VP-CD therapy group when compared with other control groups. Conclusions: Our results reveal that VP22 increases the transduction efficiency of lentivirus into NSCs and enhances the therapeutic efficacy of CD-engineered rat NSCs in the treatment for C6 glioma, demonstrating that VP22 might be a useful tool for the gene therapy of engineered NSCs and providing a potential novel strategy for enhancing the effectiveness of gene therapy in other diseases. [ABSTRACT FROM AUTHOR]

Let R be a semiprime ring with a derivation D. The focus is on the two identities with Engel condition on $${D: [x^m, D(x^{n_1}),\ldots,D(x^{n_s})]_s=0}$$ for all $${x\in R}$$ and $${[x^m, D(x)^{n_1},\ldots,D(x)^{n_s}]_s=0}$$ for all $${x\in R}$$, where s, m, n, . . . , n are fixed positive integers. Our results are natural generalizations of Posner's theorem on centralizing derivations, Herstein's theorem on derivations with power-central values and a recent result by A. Fošner, M. Fošner and Vukman. [ABSTRACT FROM AUTHOR]