Ethylene polymerization using N-Heterocyclic carbene complexes of silver and aluminum.

Various transition metal catalysts have been utilized for ethylene polymerization. Silver catalysts have attracted less attention as the catalysts, but are potential for production of high molecular weight polyethylene. Herein, we report that silver complexes with various N-heterocyclic carbene (NHC) ligands in combination with modified methylaluminoxane (MMAO) afford polyethylene with high molecular weight (melting point over 140°C). SEM observation showed that the produced polyethylene has ultra-high molecular weight. NMR investigation of the reaction between the silver complexes with organoaluminums indicate that the NHC ligands transfer from the silver complex to aluminum to produce NHC aluminum complexes. Ph3C[B(C6F5)4] abstract methyl group from the NHC aluminum complex to afford cationic aluminum complex. The NHC aluminum complex promoted ethylene polymerization in the presence of Ph3C[B(C6F5)4] and organoaluminums. NHC ligand also promoted ethylene polymerization in combination with MMAO to produce polyethylene with high melting point (140.7°C). Thus, the aluminum complexes are considered to be the actual active species in silver-catalyzed ethylene polymerization.

Ocular and extraocular sebaceous carcinomas: A retrospective study with emphasis on the presence of in situ lesion and discussion and review of the histogenesis of extraocular sebaceous carcinoma.

Sebaceous carcinoma (SC) is a rare carcinoma classified as ocular or extraocular. Ocular SC is believed to arise from the meibomian glands or the glands of Zeis. However, the origin of extraocular SC is controversial because there is no evidence of carcinoma arising from pre-existing sebaceous glands. Several hypotheses about the origin of extraocular SC have been proposed, including one suggesting an origin from intraepidermal neoplastic cells. Although extraocular SCs have been shown to occasionally comprise intraepidermal neoplastic cells, no study has investigated whether intraepidermal neoplastic cells possess sebaceous differentiation. The present study analyzed the clinicopathological features of ocular and extraocular SC, with an emphasis on the presence of in situ (intraepithelial) lesions. It retrospectively reviewed the clinicopathological features of eight patients with ocular and three patients with extraocular SC (eight women and three men; median age, 72 years), respectively. In situ (intraepithelial) lesions were observed in four of the eight ocular SC cases and one of the three extraocular SC cases and an apocrine component was noted in one patient with ocular SC (seboapocrine carcinoma). In addition, immunohistochemical analyses showed that the androgen receptor (AR) was expressed in all ocular SCs and two of the three extraocular SC cases. Adipophilin expression was observed in all ocular and extraocular SC. In situ lesions of extraocular SC showed positive immunoreactivity for both AR and adipophilin. The present study is the first to demonstrate sebaceous differentiation in in situ lesions of extraocular SC. The possible origin of extraocular SC is speculated to be the progenitor cells present in the sebaceous duct or interfollicular epidermis. The results of the present study and reported cases of SC in situ indicate that extraocular SC also arises from intraepidermal neoplastic cells.

Successful selective production of vanillic acid from depolymerized sulfite lignin and its application to poly(ethylene vanillate) synthesis.

Towards lignin upgrading, vanillic acid (VA), a lignin-derived guaiacyl compound, was produced from sulfite lignin for successfully synthesizing poly(ethylene vanillate), an aromatic polymer. The engineered Sphingobium sp. SYK-6-based strain in which the genes responsible for VA/3-O-methyl gallic acid O-demethylase and syringic acid O-demethylase were disrupted was able to produce vanillic acid (VA) from the mixture consisting of acetovanillone, vanillin, VA, and other low-molecular-weight aromatics obtained by Cu(OH)2-catalyzed alkaline depolymerization of sulfite lignin and membrane fractionation. From the bio-based VA, methyl-4-(2-hydroxyethoxy)-3-methoxybenzoate was synthesized via methylesterification, hydroxyethylation, and distillation, and then it was subjected to polymerization catalyzed by titanium tetraisopropoxide. The molecular weight of the obtained poly(ethylene vanillate) was evaluated to be Mw = 13,000 (Mw/Mn = 1.99) and its melting point was 261 °C. The present work proved that poly(ethylene vanillate) is able to be synthesized using VA produced from lignin for the first time.

Clinical study of a new skin antiseptic olanexidine gluconate in gastrointestinal cancer surgery.

BACKGROUND: Surgical site infection (SSI) is a common complication of gastrointestinal surgery. Olanexidine gluconate (OLG) is a novel skin antiseptic that is effective against a wide range of bacteria. The purpose of this study was to evaluate the bactericidal efficacy of OLG in gastrointestinal cancer surgery. METHODS: This retrospective study included a total of 281 patients who underwent gastrointestinal cancer surgery (stomach or colon). The patients were divided into two groups: 223 patients were treated with OLG (OLG group), and 58 patients were treated with povidone-iodine (PVP-I) (control group). The efficacy and safety outcomes were measured as the rate of SSI within 30 days after surgery. In addition, we conducted subgroup analyses according to the surgical approach (open or laparoscopic) or primary lesion (stomach or colon). RESULTS: There was a significant difference in the rate of SSI between the control group and OLG group (10.3% vs. 2.7%; p = 0.02). There was a significant difference in the SSI rate in terms of superficial infection (8.6% vs. 2.2%; p = 0.0345) but not in deep infection (1.7% vs. 0.5%; p = 0.371). There was no significant difference between the control group and OLG group in the overall rate of adverse skin reactions (5.2% vs. 1.8%; p = 0.157). CONCLUSION: This retrospective study demonstrates that OLG is more effective than PVP-I in preventing SSI during gastrointestinal cancer surgery.

Smooth muscle degeneration of the mesenteric and branching veins causing ischemic enteritis: a case report.

BACKGROUND: Ischemic bowel injuries are generally caused by arteriosclerosis, thromboembolism, or vasculitis. Ischemic enteritis is less common than ischemic colitis because of the rich collateral arteries of the small intestine. In the present case, smooth muscle degeneration of the mesenteric to the submucosal veins caused ischemic enteritis and small bowel obstruction. CASE PRESENTATION: An 85-year-old woman with recurrent enteritis eventually developed small bowel obstruction. We performed laparoscopic partial resection of the small intestine. The pathological findings revealed smooth muscle degeneration of the mesenteric veins that caused ischemic enteritis. Venous changes were detected not only in the injured region, but also in a part of the normal region of the resected specimen. She continued to experience some minor symptoms postoperatively; however, these symptoms subsided in a short period with medicine discontinuation. CONCLUSION: This report shows the possibility that a disease causes ischemic enteritis with unique venous pathological changes and may recur postoperatively.

Synthesis of a Ni Complex Chelated by a [2.2]Paracyclophane-Functionalized Diimine Ligand and Its Catalytic Activity for Olefin Oligomerization.

A diimine ligand having two [2.2]paracyclophanyl substituents at the N atoms (L1) was prepared from the reaction of amino[2.2]paracyclophane with acenaphtenequinone. The ligand reacts with NiBr2(dme) (dme: 1,2-dimethoxyethane) to form the dibromonickel complex with (R,R) and (S,S) configuration, NiBr2(L1). The structure of the complex was confirmed by X-ray crystallography. NiBr2(L1) catalyzes oligomerization of ethylene in the presence of methylaluminoxane (MAO) co-catalyst at 10-50 °C to form a mixture of 1- and 2-butenes after 3 h. The reactions for 6 h and 8 h at 25 °C causes further increase of 2-butene formed via isomerization of 1-butene and formation of hexenes. Reaction of 1-hexene catalyzed by NiBr2(L1)-MAO produces 2-hexene via isomerization and C12 and C18 hydrocarbons via oligomerization. Consumption of 1-hexene of the reaction obeys first-order kinetics. The kinetic parameters were obtained to be ΔG‡ = 93.6 kJ mol-1, ΔH‡ = 63.0 kJ mol-1, and ΔS‡ = -112 J mol-1deg-1. NiBr2(L1) catalyzes co-dimerization of ethylene and 1-hexene to form C8 hydrocarbons with higher rate and selectivity than the tetramerization of ethylene.

Damage-free highly efficient plasma-assisted polishing of a 20-mm square large mosaic single crystal diamond substrate.

Plasma-assisted polishing (PAP) as a damage-free and highly efficient polishing technique has been widely applied to difficult-to-machine wide-gap semiconductor materials such as 4H-SiC (0001) and GaN (0001). In this study, a 20-mm square large mosaic single crystal diamond (SCD) substrate synthesized by microwave plasma chemical vapor deposition (CVD) was polished by PAP. Argon-based plasma containing oxygen was used in PAP to modify the surface of quartz glass polishing plate, and a high material removal rate (MRR) of 13.3 µm/h was obtained. The flatness of SCD polished by PAP measured by an interferometer was 0.5 µm. The surface roughness measured by both scanning white light interferometer (SWLI) (84-µm square) and atomic force microscope (AFM) (5-µm square) was less than 0.5 nm Sq. The micro-Raman spectroscopy measurement results of mosaic SCD substrate processed by PAP showed that residual stress and non-diamond components on the surface after PAP processing were below the detection limit.

Creating Elastic Organic Crystals of π-Conjugated Molecules with Bending Mechanofluorochromism and Flexible Optical Waveguide.

To create low band-gap, fluorescent, and elastic organic crystal emitters, we focused on an extended π-conjugated system based on: a) a planar conformation,b) a rigid structure, and c) controlled intermolecular interactions. Herein, we report on two fluorescent and highly flexible organic crystals (1 and 2) which could bend under an applied stress. The bent crystals rapidly recover their straight shape upon release of the stress. Crystal 1 with a tetrafluoropyridyl terminal unit and a lower band-gap energy (orange emission, λem =573 nm, ΦF =0.50), showed no bending mechanofluorochromism and had superior performance as an optical waveguide with reddish orange emission. The waveguide performance of the crystal did not decrease under bending stress. For crystal 2 with a pentafluorophenyl terminal unit (green emission, λem =500 nm, ΦF =0.38), the original waveguide performance decreased under an applied bending stress; however, this crystal showed a unique bending mechanofluorochromism.

Cyclopolymerizations: Synthetic Tools for the Precision Synthesis of Macromolecular Architectures.

Monomers possessing two functionalities suitable for polymerization are often designed and utilized in syntheses directed to the formation of cross-linked macromolecules. In this review, we give an account of recent developments related to the use of such monomers in cyclopolymerization processes, in order to form linear, soluble macromolecules. These processes can be activated by means of radical, ionic, or transition-metal mediated chain-growth polymerization mechanisms, to achieve cyclic moieties of variable ring size which are embedded within the polymer backbone, driving and tuning peculiar physical properties of the resulting macromolecules. The two functionalities are covalently linked by a "tether", which can be appropriately designed in order to "imprint" elements of chemical information into the polymer backbone during the synthesis and, in some cases, be removed by postpolymerization reactions. The two functionalities can possess identical or even very different reactivities toward the polymerization mechanism involved; in the latter case, consequences and outcomes related to the sequence-controlled, precision synthesis of macromolecules have been demonstrated. Recent advances in new initiating systems and polymerization catalysts enabled the precision syntheses of polymers with regulated cyclic structures by highly regio- and/or stereoselective cyclopolymerization. Cyclopolymerizations involving double cyclization, ring-opening, or isomerization have been also developed, generating unique repeating structures, which can hardly be obtained by conventional polymerization methods.

Synthesis and Field-Effect Transistor Application of π-Extended Lactam-Fused Conjugated Oligomers obtained by Tandem Direct Arylation.

Five π-extended lactam-fused conjugated oligomers (5FO, 5FS, 4FPO, 4FPS, and R-4FPO) were synthesized by the tandem direct arylation. The intermolecular oxidative direct arylation was applied in the second step. These conjugated oligomers had fine-tuned FMO energies predictable by the theoretical calculation and excellent thermal stabilities. 4FPO and 4FPS bearing tetrafluoropyridine exhibited lower LUMO energy levels (-3.20 eV and -3.39 eV, respectively) compared with others. Based on the X-ray crystallography, 4FPO was found to have a herringbone crystal packing and a considerably large electron transfer integral value (137 meV). 4FPO-based bottom-gate, bottom-contact FET device demonstrated an electron mobility of 5.2×10-3  cm2 V-1 s-1 as a result of an edge-on alignment on the SiO2 substrate.

High incidence of other primary malignancies in patients with synchronous multiple gastric cancers "a multi-center retrospective cohort study".

This study evaluated the relationship between synchronous multiple gastric cancer and other primary malignancies. During 2002-2013, 1094 consecutive surgically treated gastric cancer patients were enrolled. Preoperatively, we performed total colonoscopy and whole-body computed tomography. When malignancies in other organs were suspected, detailed organ-specific examinations were performed. Synchronous multiple gastric cancer occurred in 102 patients (9.3%)which was frequently observed in patients with preoperative other primary malignancies (p < 0.001). Preoperative other primary malignancy was an independent risk factor for synchronous multiple gastric cancer (p = 0.001; hazard ratio: 2.145, 95% confidence interval: 1.354-3.399) and an independent prognostic factor of overall survival in patients undergoing gastrectomy with curative intent (p = 0.021; hazard ratio: 1.481, 95% confidence interval: 1.060-2.070). Thus, patients with preoperative other primary malignancies have a high risk of synchronous multiple gastric cancer. Careful preoperative examination is recommended to improve survival.

Three Cases of Pseudo-Meigs' Syndrome Secondary to Ovarian Metastases from Colorectal Cancer.

Pseudo-Meigs' syndrome is used to describe cases of ascites and/or pleural effusion associated with ovarian neoplasms other than benign tumors, which improve after removal of the ovarian lesion. We present three cases of pseudo-Meigs' syndrome secondary to ovarian metastasis from colorectal cancer. In case 1, the patient has severe dyspnea and hypoxia due to massive right pleural effusion; therefore preoperative thoracic drainage was needed. In case 2, the patient needed paracentesis every two or three days to improve abdominal distension. After two courses of 5-fluorouracil, levofolinate, and oxaliplatin (mFOLFOX6), her ascites could be controlled by diuretics without aspiration and her general condition improved. Then she underwent operation. In case 3, the patient developed a massive pleural effusion and ascites coincident with a rapid enlargement of ovarian tumor after resection and adjuvant chemotherapy for rectal cancer. In all cases, pleural effusions and/or ascites resolved and general conditions and daily activities of the patients improved after oophorectomy. They are all currently in good health without recurrence of pleural effusion or ascites. In patients with suspected pseudo-Meigs' syndrome secondary to ovarian metastasis of colorectal cancer, operation including oophorectomy may reduce pleural effusions and/or ascites and improve the general condition.

Direct Nanoscale Sensing of the Internal Electric Field in Operating Semiconductor Devices Using Single Electron Spins.

The electric field inside semiconductor devices is a key physical parameter that determines the properties of the devices. However, techniques based on scanning probe microscopy are limited to sensing at the surface only. Here, we demonstrate the direct sensing of the internal electric field in diamond power devices using single nitrogen-vacancy (NV) centers. The NV center embedded inside the device acts as a nanoscale electric field sensor. We fabricated vertical diamond p-i-n diodes containing the single NV centers. By performing optically detected magnetic resonance measurements under reverse-biased conditions with an applied voltage of up to 150 V, we found a large splitting in the magnetic resonance frequencies. This indicated that the NV center senses the transverse electric field in the space-charge region formed in the i-layer. The experimentally obtained electric field values are in good agreement with those calculated by a device simulator. Furthermore, we demonstrate the sensing of the electric field in different directions by utilizing NV centers with different N-V axes. This direct and quantitative sensing method using an electron spin in a wide-band-gap material provides a way to monitor the electric field in operating semiconductor devices.

Inversion channel diamond metal-oxide-semiconductor field-effect transistor with normally off characteristics.

We fabricated inversion channel diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with normally off characteristics. At present, Si MOSFETs and insulated gate bipolar transistors (IGBTs) with inversion channels are widely used because of their high controllability of electric power and high tolerance. Although a diamond semiconductor is considered to be a material with a strong potential for application in next-generation power devices, diamond MOSFETs with an inversion channel have not yet been reported. We precisely controlled the MOS interface for diamond by wet annealing and fabricated p-channel and planar-type MOSFETs with phosphorus-doped n-type body on diamond (111) substrate. The gate oxide of Al2O3 was deposited onto the n-type diamond body by atomic layer deposition at 300 °C. The drain current was controlled by the negative gate voltage, indicating that an inversion channel with a p-type character was formed at a high-quality n-type diamond body/Al2O3 interface. The maximum drain current density and the field-effect mobility of a diamond MOSFET with a gate electrode length of 5 µm were 1.6 mA/mm and 8.0 cm(2)/Vs, respectively, at room temperature.

Synthesis of Optically Active Polystyrene Catalyzed by Monophosphine Pd Complexes.

Cationic Pd(II) monophosphine complexes derived from α- and ß-cyclodextrins (CDs) promote the homopolymerization of styrene under carbon monoxide pressure. Although reversible CO coordination takes place under catalytic conditions according to (13) C NMR studies with (13) C-enriched CO, both complexes catalyze the formation of CO-free styrene polymers. These macromolecules display optical activity as a result of the presence of stereoregular sequences within the overall atactic polymer.

Factors related to dementia patients' length of day-care clinic attendance.

BACKGROUND: In our previous study, we reported that patients using a day-care clinic for less than 1 year were older than those who continued day-care activities for more than 1 year. We found that dementia symptoms, as assessed by caregivers using the initial Assessment Scale for Symptoms of Dementia score, influenced the length of day-care clinic attendance (LDC). However, these results were obtained by univariate analysis. In this study, we investigated the factors that influenced LDC using multivariate analysis. METHODS: We studied data from 457 patients with dementia who attended our day-care clinic for dementia patients from 1 April 2000 to 31 March 2012 and continued intervention until 31 March 2013. We evaluated the factors that influenced LDC using Cox's proportional hazards model for each sex. RESULTS: Kaplan-Meier analysis showed a gender difference in LDC. The median LDC was 18 months (interquartile range: 3-37 months) for men and 21 months (interquartile range: 5-53 months) for women (P = 0.027). In model 1, the low initial Assessment Scale for Symptoms of Dementia score for each sex and high initial scores for Hasegawa's Dementia Scale-Revised and Nishimura's activity of daily living scale in women were related to the long-term use of day care. Model 2 indicated that a low final score for Nishimura's activity of daily living scale increased LDC for each sex. LDC was not affected by variables related to the caregiving system except for the number of cohabitants in men. CONCLUSIONS: It was suggested that patients with high cognitive and physical functions attend the day-care clinic for a long time. It was necessary to control the behavioural and psychological symptoms of dementia for those using day care in the long term. However, patients with low physical function at the end of day-care attendance may also attend our day-care service in the long term if they receive favourable assistance.

Olefin Polymerization Catalyzed by Double-Decker Dipalladium Complexes: Low Branched Poly(α-Olefin)s by Selective Insertion of the Monomer Molecule.

Dipalladium complexes of a cyclic bis(diimine) ligand with a double-decker structure catalyze polymerization of ethylene and α-olefins and copolymerization of ethylene with 1-hexene. The polymerization of 1-hexene yields a polymer that is mainly composed of the hexamethylene unit formed by 2,1-insertion of the monomer into the palladium-carbon bond, followed by chain-walking (6,1-insertion). The polymerization of 4-methyl-1-pentene proceeds by 2,1-insertion with a selectivity of 92-97 %, and affords the polymer with methyl and 2-methylhexyl branches. 2,1-Insertion occurs selectively in all of the polymerization reactions of α-olefins catalyzed by the dipalladium complexes. Ethylene polymerization with the catalyst at 100 °C lasts over 24 h, whereas the monopalladium-diimine catalyst loses its activity within 8 h at 60 °C. Polyethylene obtained by the dipalladium catalyst is less-branched and has a higher molecular weight compared to that of the monopalladium catalyst under the same conditions. Copolymerization of ethylene with 1-hexene affords solid products with melting points and molecular weights that vary depending on the polymerization time, suggesting formation of a block and/or gradient copolymer.

Postoperative complications in elderly patients with gastric cancer.

BACKGROUND: Elderly patients undergoing gastrectomy are expected to be at high risk of postoperative complications. This retrospective multicenter cohort study assessed complications and long-term outcomes after gastrectomy for gastric cancer (GC). METHODS: A total of 993 patients with GC who had undergone gastrectomy were included, comprising 186 elderly patients (age ≥ 80 y, E group) and 807 nonelderly patients (age ≤ 79 y, NE group). Preoperative comorbidities, operative results, postoperative complications, and clinical outcomes were compared between the groups. RESULTS: Clavien-Dindo grade ≥1 postoperative complications, pneumonia (P = 0.02), delirium (P < 0.001), and urinary tract infection (P < 0.001) were more common in the E group. Postoperative pneumonia was associated with mortality in this group (P < 0.001). Three patients (1.6%) died after surgery, each of whom had pneumonia. Severe postoperative complication was independently prognostic of overall (hazard ratio, 4.69; 95% confidence interval, 2.40-9.14; P < 0.001) and disease-specific (hazard ratio, 6.41; 95% confidence interval 2.92-14.1; P < 0.001) survival in the E group. CONCLUSIONS: In elderly patients with GC, clinical outcomes are strongly associated with severe postoperative complications. Preventing such complications may improve survival.

Prevalence and management of colorectal neoplasia in surgically treated esophageal cancer patients.

AIMS: The existence of other primary tumors during the treatment of esophageal cancer patients has been an important issue. Our aim is to investigate the prevalence and management of colorectal neoplasia (CRN) in surgically treated esophageal cancer patients. METHODS: Between 2002 and 2008, 93 patients with esophageal cancer were surgically treated. Seventy-three patients underwent subtotal esophagectomy and 20 underwent lower esophagectomy for esophageal cancer. Colonoscopy was available for detecting CRN before and after surgery. RESULTS: Eighty-nine (95.7%) of the 93 patients were screened by colonoscopy preoperatively or within a year from the operation. Thirty-nine patients (43.8%) with CRN were synchronously identified: adenoma in 34 (38.2%) and adenocarcinoma in 5 patients (5.6%). Eleven adenomas with high grade-dysplasia and 8 adenomas with low grade-dysplasia were removed endoscopically. Three superficial adenocarcinomas were endoscopically removed before surgery, and 2 adenocarcinomas were surgically removed. Seventy-four patients (83.1%) were followed using colonoscopy, and 11 subsequent CRN, including 2 superficial adenocarcinomas, were endoscopically detected in 8 patients (10.8%). The size of esophageal cancer was larger in the patients with than without CRN (p = 0.036). The body mass index in esophageal cancer patients with CRN tended to be higher than in those without CRN (p = 0.065). CONCLUSIONS: We noted that esophageal cancer is frequently associated with synchronous and/or metachronous colorectal cancer and adenomas. Colonoscopy is useful to detect and manage CRN before and after esophagectomy, although a few limitations exist.

Diastereoselective cyclization of an aminobenzoic acid derivative and chiroptical properties of triple-stranded helical bis(phenylethynyl)benzene.

The diastereoselective cyclization of 2,5-dibromo-4-hexylaminobenzoic acid was achieved by the microwave-assisted condensation using SiCl4. Moreover, the triple-stranded helical structure of bis(phenylethynyl)benzene units embedded in the cyclic tri(benzamide) scaffold was obtained by a Sonogashira-Hagihara coupling reaction. Two optically active enantiomers that do not racemize even at the elevated temperature were separated by chiral HPLC. The chiral helical topology was revealed by the spectroscopic data and theoretical calculation.