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Conductivity reconstruction in an inverse eddy current problem is considered in the present paper. With the electric field measurement on part of domain boundary, we formulate the reconstruction problem as a constrained optimization problem with total variation regularization. The existence and stability are proved for the solution to the optimization problem. The finite element method is employed to discretize the optimization problem. The gradient Lipschitz property of the objective functional is established for the discrete optimization problem. We propose a novel modification to the traditional alternating direction method of multipliers, and prove the convergence of the modified algorithm. Finally, we show some numerical experiments to illustrate the efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, the authors propose Neumann series neural operator (NSNO) to learn the solution operator of Helmholtz equation from inhomogeneity coefficients and source terms to solutions. Helmholtz equation is a crucial partial differential equation (PDE) with applications in various scientific and engineering fields. However, efficient solver of Helmholtz equation is still a big challenge especially in the case of high wavenumber. Recently, deep learning has shown great potential in solving PDEs especially in learning solution operators. Inspired by Neumann series in Helmholtz equation, the authors design a novel network architecture in which U-Net is embedded inside to capture the multiscale feature. Extensive experiments show that the proposed NSNO significantly outperforms the state-of-the-art FNO with at least 60% lower relative L2-error, especially in the large wavenumber case, and has 50% lower computational cost and less data requirement. Moreover, NSNO can be used as the surrogate model in inverse scattering problems. Numerical tests show that NSNO is able to give comparable results with traditional finite difference forward solver while the computational cost is reduced tremendously. [ABSTRACT FROM AUTHOR]

The pore structure of a carbonate reservoir determines the fluidity and storage characteristics of hydrocarbon, and it is vital for reservoir evaluation and oil and gas production. The Visean and Serpukhovian carbonate reservoirs in the Marsel exploration area of the Chu-Sarysu Basin possess a complex lithology and pore structure, which significantly affect production efficiency. The pore structure of the reservoirs was investigated in this study via X-ray diffraction, conventional petrophysical measurements, cast thin section analysis, scanning electron microscopy (SEM), imaging logging, and high-pressure mercury injection (HPMI). The findings show that the lithology in this area mainly comprises fine-grained limestone, bioclastic limestone, and silty limestone; moreover, the mineral assemblage in this region is markedly different. The types of carbonate reservoir pore spaces are complex and diverse. Primary pores are mainly biological cavity pores with small pore size, mostly isolated individuals, poor connectivity, and weak percolation capacity. Secondary dissolution pores, which are dominated by intergranular dissolution pores, intragranular dissolution pores, and microfractures, are the dominant storage spaces in the Carboniferous carbonate reservoirs. Through an innovative approach of combining imaging logging and cast thin section analysis, it was concluded that mainly three types of fractures exist, namely conductivity fractures, fissures, and resistive fractures. Moreover, structural fractures in this area are relatively developed, which substantially increases the percolation capacity of the reservoirs and it is conducive to oil and gas flow. However, some structural fractures are filled with calcite, destroying the effectiveness of the fractures and reducing the percolation capacity. Based on capillary pressure curves, the samples were divided into three types, of which the physical properties decrease in the order of type I > type III > type II. The fractal dimensions obtained from HPMI and SEM data characterize the complexity of the reservoir microstructure in the study area. The formation of high-porosity and high-permeability zones was caused by quasi-syngenetic dolomitization and syngenetic–quasi-syngenetic dissolution. In this study, the pore structure of carbonate reservoirs in the area was evaluated quantitatively, which is highly significant to improving oil and gas recovery. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of chloroesters by the reaction of ethers with acyl chlorides catalyzed by nano-ZnO under solvent-free condition at room temperature was described. The method is compatible with a range of ethers including tricyclic ethers, tetracyclic ethers, pentacyclic ethers and hexacyclic ethers and have afforded the products with moderate to good yields. The ZnO could be reused up to three times and the product yield after three cycles is 87%. [ABSTRACT FROM AUTHOR]

With the shortage of global fossil energy resource and the emergence of ecological crisis, concerns toward energy issues have risen to an unprecedented level. People have begun to seek potential and sustainable solutions to energy problems, developing energy materials with green blocks, so as to provide technical support for the reliability and advancement of future living environment. As an alternative method for constructing sustainable materials by assembling scattered nanocellulose building blocks using bottom-up technology, the integrated nano-architectonic from wood has attracted more and more attention in energy areas. Based on the current hotspots of high performance batteries, solar steam generation and building energy efficiency, this review describes the significance of wood nanotechnology for sustainable energy development. [ABSTRACT FROM AUTHOR]

Mesoporous silica nanoparticle was expected to provide a versatile drug delivery platform with modification flexibility. To improve its hemocompatibility and realize controlled and/or targeting drug release, modification of bare mesoporous silica nanoparticles is essential. Herein, a novel method of coating mesoporous silica nanoparticles with lipid bilayers was developed. First, a homemade organosiloxane precursor was used for hydrophobic modification of mesoporous silica nanoparticles, then phospholipids (1,2-dihexadecanoyl- sn-glycero-3-phosphocholine and 1,2-distearoyl- sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)]) were coated by a filming-rehydration method based on hydrophobic interaction. The nanoparticle samples were characterized by transmission electron microscope, dynamic light scattering, nitrogen sorption, Fourier transform infrared, and thermal gravimetric analysis. Furthermore, the novel lipid bilayer coated mesoporous silica nanoparticles were compared with bare mesoporous silica nanoparticles in terms of suspension stability, drug release, hemolysis, and nonspecific protein absorption. Our data proved that lipid bilayer coated mesoporous silica nanoparticles had better hemobiocompatibility and controlled drug release properties than that of bare mesoporous silica nanoparticles. Graphical Abstract: [ABSTRACT FROM AUTHOR]

In this article, a novel yolk-shell structure of silica-based nanosphere with a spherical silica-coated nanogold core was successfully fabricated on the basis of layer-by-layer co-assembly and selective etching strategies. The resulting nanospheres were characterized by transmission electron microscopy, scanning electron microscopy, ultraviolet and visible spectrophotometry, X-ray diffractometry, and nitrogen adsorption-desorption. The results showed that the uniform yolk-shell structured nanospheres have a narrow size distribution. Specially, the as-synthesized particles possess a specific surface area (270 m g) and pore volume (0.57 cm g). It is believed that the material obtained possesses great potential applications in the fields of biomedical engineering, catalysis, and computed tomography contrast for its above properties. Graphical Abstract: Apparently, the graphical abstract lets out two important messages. Firstly, the synthesis process is intelligible at first glance. Secondly, the TEM image of resulting particle shown in right corresponds well with the schematic illustration.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

IR-780, a novel near-infrared (NIR) fluorescent probe, was synthesized and applied to living cells. The probe exhibited good fluorescent characteristic, and cell experiments showed the probe had high affinity and without apparent cytotoxicity. Fluorescent image experiments in living A549 (Human lung adenocarcinoma epithelial cell line) and L929 (mouse fibroblast cell line) cells, further demonstrated its potential applications in biological systems. The probe effectively prevented the influence of autofluorescence and native cellular species in biological systems. It also exhibited excellent cell membrane permeability, good photostability, and high sensitivity. [ABSTRACT FROM AUTHOR]

A novel and convenient method for the preparation of 5-benzoyl-1,4-naphthoquinone is reported for the first time. The process starts with condensation of malonic acid, followed by Diers-Alder cyclization, methylation, aromatization, hydrolysis, Friedel-Crafts acylation, and oxidation. The new synthesis procedure with high yields does not require special conditions and column chromatographic purification. The method involves readily available reagents and has been demonstrated to be suitable for large-scale preparation. [ABSTRACT FROM AUTHOR]

A novel near-infrared fluorescent probe, IR-736, was synthesized and applied to living cells. The probe exhibited good response fluorescent characteristic, and cells experiments showed the probe had high affinity and without apparent cytotoxicity. Fluorescent image experiments in living L929 cells, MCF-7 cells, HepG2 cells, further demonstrated its potential applications in biological systems. The probe effectively prevented the influence of autofluorescence and native cellular species in biological systems. It also exhibited good photostability, and excellent cell membrane permeability. [ABSTRACT FROM AUTHOR]

Anaplastic lymphoma kinase (ALK) is an important and attractive target for the design of new anticancer drugs. In the present study, quantitative structure-activity relationship (QSAR) models of piperidine carboxamide derivatives against ALK were developed by CoMFA and CoMSIA approaches. Both the CoMFA and CoMSIA models yielded significant statistical results. The results of the QSAR model indicated the importance of steric, electrostatic, and hydrophobic properties in the potent ALK inhibitors. Furthermore, molecular docking of the most active compound 25 with the active site of ALK was also investigated. The outcomes of this study may result in a better understanding of the inhibition mechanism of ALK and aided in the development of new and more potent anticancer drugs. [ABSTRACT FROM AUTHOR]

A new near-neutral pH near-infrared (NIR) fluorescent probe utilizing a fluorophore-receptor molecular framework that can modulate the fluorescence emission intensity through a fast photoinduced electron transfer process was developed. Our strategy was to choose tricarbocyanine (Cy), a NIR fluorescent dye with high extinction coefficients, as a fluorophore, and N-methylpiperazine (MP) as a receptor. The pH titration indicated that MP-Cy can monitor the minor physiological pH fluctuations with a p Ka of ∼7.10 near physiological pH, which is valuable for intracellular pH researches. The probe responds linearly and rapidly to minor pH fluctuations within the range of 3.05-7.10 and exhibits strong dependence on pH changes. As expected, the real-time imaging of cellular pH and the detection of pH in situ was achieved successfully in living HepG2 cells by this probe. It is shown that the probe effectively avoids the influence of autofluorescence and native cellular species in biological systems and meanwhile exhibits high sensitivity, good photostability, and excellent cell membrane permeability. [ABSTRACT FROM AUTHOR]

In this study, a novel artificial hybrid vesicle, nano silver particles decorated cerasome were fabricated through sol-gel and self-assemble methods as well as in situ reduction. Samples were characterized in terms of hydrodynamic size and surface morphology via dynamic light scattering as well as scanning and transmission electron microscopies. Analysis through energy dispersive X-ray spectrometer proved the existence of silver particles. Due to the high morphological stability of cerasome, Silver nanoparticles with a size of about 5-10 nm can be deposited on the surface without any stabilizers. The UV spectra revealed a single symmetric extinction peak at 406 nm, confirming the spherical shape of the synthesized silver nanoparticles. Several reducing agents were screened before confirming sodium borohydride (NaBH). Comparison of different NaBH/lipid ratios (K) was then carried out in order to ascertain its effect. Investigation of the stability of this hybrid vesicles was carried out, indicating that it can be stored at 4 °C for at least 3 months without any morphological change. Results demonstrated that this hybrid vesicle has excellent morphological stability, which impart it significant potential for various applications such as being an antibacterial material and a radio sensitization agent. [ABSTRACT FROM AUTHOR]

A series of novel benzofuran carboxylic acid derivatives have been designed and synthesized, with their antagonism effect screened on ET-1-induced contraction in the rat thoracic aortic ring. Some target compounds demonstrated significant inhibitory activity, especially benzo[ c]thiadiazole and benzo[ c]oxadiazole compounds 29 and 30 showed potent inhibition percentage higher than the contrast compound BQ123. Further affinity and selectivity for ET binding assay showed that 29 demonstrated a dual ET/ET antagonism activity in nanomole level. Moreover, 30 was effective in relieving hypoxia-induced pulmonary arterial hypertension. [ABSTRACT FROM AUTHOR]

Breast cancer is the most common malignancy and leading cause of cancer mortality in women. Drug resistance is a major obstacle in systemic therapy of breast cancer, which leads therapeutic failure, incontrollable disease, and mortality. MiRNAs are an emerging field in cancer research. Recent evidence demonstrates that miRNAs are core regulators in drug resistance of breast cancer. Preclinical research reveals that miRNAs modulate the multidrug-resistant signal transduction network through up-regulated drug efflux transporters and anti-apoptotic proteins, acquisition of epithelial-mesenchymal transition, and formation of cancer stem cells. MiRNAs mediate endocrine resistance through modulating ERα expression, receptor tyrosine kinase signaling, cell survival signaling, and apoptosis. Such emerging evidence indicates that miRNAs could be potential biomarkers for predicting a response to systemic therapy and prognosis in clinical settings. Targeting specific miRNAs of the drug-resistant network is promising in overcoming drug resistance in breast cancer. [ABSTRACT FROM AUTHOR]

Purpose: Solid-pseudopapillary neoplasms (SPNs) are rare pancreatic tumors, with a low potential for malignancy. The clinical and pathological features of 33 SPNs were reviewed. Methods: This study conducted a retrospective analysis of 33 patients who underwent surgery for a pathologically confirmed SPN from 2000 to 2011. Results: Thirty of the 33 patients (91 %) were female, and the median age at diagnosis was 29.2 years (range 12-59). The most common symptom was abdominal discomfort with dull pain (58 %). Others included asymptomatic lesions that were only detected incidentally during imaging (21 %), a palpable abdominal mass (15 %) and indigestion (6 %). All 33 patients underwent surgery with a curative intent and 3 (9 %) underwent laparoscopic surgery. The mean diameter of the tumors was 4.9 cm (range 2-15 cm), and they occurred in the head (9, 27 %), neck (5, 15 %), body or tail (19, 58 %) of the pancreas. One patient had lymph node metastases, one patient had portal venous invasion and 8 patients had perineural invasion. The patient follow-up ranged from 4 to 118 months, and 32 patients were alive and well without recurrence. One patient relapsed 10 months after distal pancreatectomy with splenectomy and underwent a second surgery via laparotomy. Unfortunately, the patient died of multiple organ failure 12 days after the second surgery. Conclusion: SPNs are rare neoplasms with malignant potential but excellent prognosis. Adequate surgical resection, including laparoscopic surgery, may therefore be performed safely and is associated with a long-term survival, even in invasive cases. [ABSTRACT FROM AUTHOR]

Drug resistance remains a major clinical obstacle to successful treatment in breast cancer patients, and the evidence of microRNAs involvement in cancer drug resistance has been emerging recently. However, the role of microRNA-200c (miR-200c) in modulating chemoresistance of breast cancer remains largely unexplored. Here, we investigated the miR-200c expression in tumor specimens obtained from thirty-nine breast cancer patients who received neoadjuvent chemotherapy by quantitative real-time PCR. Down-regulated miR-200c was observed in non-responders as compared to responders. In addition, miR-200c expression was observed to be down-regulated over 800-fold in human breast cancer cells resistant to doxorubicin MCF-7/ADR as compared to the parental MCF-7 cells. Up-regulation of miR-200c with transfection of miR-200c mimics in breast cancer cells could enhance the chemosensitivity to epirubicin and reduce expression of multidrug resistance 1 mRNA and P-glycoprotein. Moreover, our study demonstrated that restoration of miR-200c in MCF-7/ADR cells could increase intracellular doxorubicin accumulation determined by flow cytometry. Taken together, our findings suggest that miR-200c may act as a promising therapeutic target for improvement of responsiveness to chemotherapy in breast cancer. [ABSTRACT FROM AUTHOR]

Objective: The aim of our study was to identify clinicopathological characteristics as predictive factors for gastric cancer tumours of less than 2 cm in diameter. Methods: The clinicopathological features of 129 patients with gastric cancer tumour of less than 2 cm in diameter were reviewed retrospectively from hospital records between 1980 and 2000. The results of retrospective analysis of clinicopathological data of 58 patients with advanced cancer were compared with those of 71 patients with early cancer. Univariate and multivariate analyses of patients with gastric cancer tumours were performed to evaluate the prognostic significance of clinicopathological features. Results: Lymph-node metastasis was found more frequently in the advanced cancer group than in the early cancer group. In univariate analysis, unfavorable prognostic factors included deep cancer invasion. Using Cox's proportional hazard regression model, only depth of invasion emerged as an independent statistically significant prognostic parameter associated with long-term survival. Conclusion: Depth of invasion is an independent prognostic factor for gastric cancer tumours of less than 2 cm in diameter. Laparoscopic surgery should not be performed on tumours that are diagnosis in advanced stage and lymph-node involvement. We recommend laparoscopic surgery involving local resection of the stomach without lymphadenectomy for small, early gastric cancer tumours. However, the validity of this recommendation should be tested by a prospective randomized control trial in the future. [ABSTRACT FROM AUTHOR]

To identify clinicopathological characteristics as predictive factors for lymph node metastasis in submucosal gastric cancer, and in addition to establish objective criteria as indications for endoscopic submucosal dissection (ESD). Data from 130 patients with submucosal gastric cancer were collected, and the relationship between their clinicopathological characteristics and the presence of lymph node metastasis was retrospectively analyzed by multivariate analysis. In the multivariate logistic regression model, a tumor size of 2 cm or more and an undifferentiated histologic type were found to be independent risk clinicopathological characteristics for lymph node metastasis. Among 130 patients with submucosal carcinoma, no lymph node metastases were observed in 17 patients who showed neither of the two risk clinicopathological characteristics. Lymph node metastasis occurred in 61.1% (22/36) of the patients who had both risk clinicopathological characteristics. A tumor size of 2 cm or more and an undifferentiated histologic type were significantly and independently related to lymph node metastasis in submucosal gastric cancer. It is rational for the paitients with neither of these two independent risk clinicopathological characteristics to undergo an ESD. [ABSTRACT FROM AUTHOR]

To investigate the prognosis of advanced gastric carcinoma patients with liver metastasis, and provide a foundation for rational operations. The operations and prognosis of 102 primary gastric carcinoma patients with liver metastasis were studied retrospectively. In gastric carcinoma patients with H1 metastasis who underwent a resection operation, the 6-month, 1-and 2-year post-operative survival rates were 61%, 42% and 7%. There was a statistically significant difference in survival between resected and non-resected patients(P=0.000) In gastric carcinoma cases with H2 metastasis, resection operations resulted in 54%, 16% and 8% respective survival rates, with no significant difference compared to patients not receiving a resection(P=0.132). Gastric carcinoma patients with H3 metastasis who received a resection operation showed 25%, 13% and 0% respective survivals with no significantly better prognosis compared to the non-resected cases(P=0.135). There was no statistically significant difference in survival between the cases with or without peritoneal metastasis (P=0.152). A resection operation provides a better prognosis for gastric carcinoma patients with H1 metastasis independent of peritoneal metastasis, but resection has no benefit for gastric carcinoma cases with H2 or H3 metastasis. Peritoneal metastases are not the significant influencing factor for the prognosis of gastric cancer with liver metastasis. [ABSTRACT FROM AUTHOR]

OBJECTIVE The purpose of the study was to examine the efficacy of treating patients with advanced gastric cancer using iodine - 125 (125I) brachytherapy. METHODS Ten patients with unresectable advanced gastric cancer were selected based on their pattern of CT scans. We utilized a brachytherapy planning system to determine the distribution of the 125I seeds, their activity and quantity. The matched peripheral dose (MPD) was 110–135 Gy. 125I seeds were implanted in a single plane or biplane by an intraoperative small incision or percutaneous puncture. The postoperative hemogram, CT, KPS, pain-relieving period and survival period were recorded. RESULTS One patient developed a complete response (CR), 4 patients a partial response (PR), 3 patients showed no change (NC) and 2 patients developed progressive disease (PD). The overall response rate (CR+PR) was 50% (5/10). The pain-relieving rate was 89% (8/9). The patients’ appetite and KPS were improved. The longest survival period was 10 months and median life span was 4 months. There were 8 patients whose seeds fell off resulting in an expulsion rate of 3.8% (26/692). The patients showed 0–1 degree acute radio-therapeutic side-effects without other symptoms such as abdominal pain, vomitus cruentes or intestinal obstruction etc. CONCLUSION Applying 125I implantation to treat advanced gastric cancer with a reasonable seed distribution can significantly improve clinical symptoms and their quality of life. The radioactive damage is mild. This method can be used as an important supplementary treatment for unresectable advanced gastric cancer. [ABSTRACT FROM AUTHOR]

To identify clinicopathological characteristics as predictive factors for recurrence in early gastric cancer (EGC), and to determine which lesions should be removed by gastrectomy by means other than endoscopic mucosal resection (EMR). Data from 249 patients with EGC were collected and the relationship between their clinicopathological characteristics and postoperative recurrence was retrospectively analyzed by univariate analysis. Of the 249 patients after gastrectomy, 19 cases (7.6%) experienced a recurrence. The postoperative recurrence rate was 18.9% (7/37) in patients with lymph node metastasis, and 5.7% (12/212) in those without. Lymph node metastases were found to be significantly related to recurrence in EGC ( P = 0.005). Lymph node metastases were the only predictive factor for recurrence in EGC. However, this was not the determining factor for performing gastrectomy rather than EMR. Although after gastrectomy with lymphadenectomy of EGC, patients with lymph node metastasis should be considered as candidates for adjuvant treatment. For lymph-node metastatic EGCs, adjuvant therapy is recommended following gastrectomy with lymphadenectomy. [ABSTRACT FROM AUTHOR]

To investigate the distribution pathway of sentinel lymph nodes (SLN) in middle third gastric carcinoma, as the foundation for rational lymphadenectomy. 52 cases of middle third tumors with solitary lymph nodes from 1852 gastric carcinomas were selected. The locations and histological types of metastatic lymph nodes were analyzed retrospectively. Of 52 solitary node metastases cases, 37 were limited to perigastric nodes (N1), while 15 with skipping metastasis. In the 35 cases with tumor of lesser curvature, there were 17 cases found lymph nodes of the lesser curvature side (No. 3), 5 cases involved lymph nodes of the greater curvature (No. 4), and 8 cases with lymph nodes of the left gastric artery (No. 7). In the 17 cases with tumor of greater curvature, 7 cases spread to No. 4, while 3 metastasized to lymph nodes of the spleen hilum (No. 10). The difference of the histological types in groups N1 and over N1, were not statistically significant ( P > 0.05). Adjacent metastasis formed the primary distribution pattern of SLN in middle third gastric carcinoma, transversal and skipping metastases being also notable. [ABSTRACT FROM AUTHOR]

An efficient and inexpensive synthesis of N-substituted amides from the reaction of nitriles with methyl ethers catalyzed by Fe(ClO4)3·H2O is described. Fe(ClO4)3·H2O is an economically efficient catalyst for the Ritter Reaction under solvent-free conditions. A range of methyl ethers (benzyl, sec-alkyl and tert-butyl ethers) were reacted with nitriles to provide the corresponding amides in high–excellent yields. [ABSTRACT FROM AUTHOR]