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The rupture of macrophage phagosomes has been implicated in various human diseases and plays a critical role in immunity. However, the mechanisms underlying this process are complex and not yet fully understood. This study describes the development of a robust engineering method for rupturing phagosomes based on a well-defined mechanism. The method utilizes microfabricated microparticles composed of uncrosslinked linear poly(N-isopropylacrylamide) (PNIPAM) as phagocytic objects. These microparticles are internalized into phagosomes at 37 °C. By exposing the cells to a cold shock at 0 °C, the vast majority of the microparticle-containing phagosomes rupture. The percentage of phagosomal rupture decreases with the increase of the cold-shock temperature. The osmotic pressure in the phagosomes and the tension in the phagosomal membrane are calculated using the Flory–Huggins theory and the Young–Laplace equation. The modeling results indicate that the osmotic pressure generated by dissolved microparticles is probably responsible for phagosomal rupture, are consistent with the experimentally observed dependence of phagosomal rupture on the cold-shock temperature, and suggest the existence of a cellular mechanism for resisting phagosomal rupture. Moreover, the effects of various factors including hypotonic shock, chloroquine, tetrandrine, colchicine, and l-leucyl-l-leucine O-methyl ester (LLOMe) on phagosomal rupture have been studied with this method. The results further support that the osmotic pressure generated by the dissolved microparticles causes phagosomal rupture and demonstrated usefulness of this method for studying phagosomal rupture. This method can be further developed, ultimately leading to a deeper understanding of phagosomal rupture.

A sarcopenia diagnosis is confirmed by the presence of low muscle quantity or quality under the 2018 revised definition by the European Working Group on Sarcopenia in Older People 2. Imaging methods [i.e. magnetic resonance imaging (MRI)], dual‐energy X‐ray absorptiometry (DXA), and bioelectrical impedance analysis are tools to evaluate muscle quantity or quality. The present study aimed to investigate whether and how low‐intensity and moderate‐intensity resistance training improved both muscle quantity and quality measured by MRI, DXA, and segmental bioelectrical impedance spectroscopy (S‐BIS) in middle‐aged and older people. A single‐blind, randomized, controlled trial was conducted. Community‐dwelling people aged 50–79 years were randomly allocated to no exercise (no‐Ex), low‐intensity exercise (low‐Ex), and moderate‐intensity exercise (moderate‐Ex) groups. Participants in the exercise groups performed resistance training for 24 weeks, with loads of 40% and 60% of one repetition maximum in the low‐Ex and moderate‐Ex groups, respectively. Cross‐sectional area (CSA), lean mass, and muscle electrical properties on S‐BIS were used to determine the effects of training interventions on muscle quantity and quality of the lower limbs. Fifty participants (no‐Ex 17, age 63.5 ± 8.5 years, women 47.1%; low‐Ex 16, age 63.6 ± 8.1 years, women 50.0%; moderate‐Ex 17, age 63.5 ± 8.3 years, women 52.9%) completed the 24 week exercise intervention. For the primary outcome, significant intervention effects were found in thigh muscle CSA on MRI between the moderate‐Ex and no‐Ex groups (+6.8 cm2, P< 0.01). Low‐Ex for 24 weeks only increased quadriceps CSA (+2.3 cm2, P< 0.05). The per cent change of thigh muscle CSA (+7.0%, P< 0.01) after 24 week moderate‐Ex was higher than that of leg lean mass on DXA (+2.3%, P= 0.088). Moderate‐Ex for 24 weeks also improved S‐BIS electrical properties related to muscle quantity and quality, including the intracellular resistance index (+0.1 cm2/Ω, P< 0.05), membrane capacitance (+0.7 nF, P< 0.05), and phase angle (+0.3 deg, P< 0.05); their changes were positively correlated with that of thigh muscle CSA (P< 0.01). Resistance exercise with moderate intensity improved muscle quantity and quality measured by MRI and S‐BIS, whereas that with low intensity only increased muscle quantity in middle‐aged and older people. The comparisons among the responses to exercise between the assessment methods indicate the greater value of MRI and S‐BIS to measure changes of muscle quantity and quality than of lean mass measured by DXA for assessing the local effects of resistance training.

The specific structural arrangement of atoms in the different crystalline phases of a polymorph material has a significant influence on their electrochemical behavior. Herein, we have demonstrated the proton conductivity of titanium dioxide (TiO2) nanosheets based on their different crystalline phases. The successful preparation of three different crystalline phases including rutile (r-TiO2), anatase (a-TiO2) and brookite (b-TiO2) with the sheet size within nanometer range was confirmed using powder X-ray diffraction (PXRD) and transmission electron microscope (TEM) analysis. The corresponding TiO2membrane films were prepared through a reduced pressure-driven route followed by humidity and temperature-dependent proton conductivities measurement. At room temperature and 90% relative humidity, b-TiO2shows a high proton conductivity of 3.04 × 10−3S cm−1which is almost one order higher than a-TiO2(4.41 × 10−4S cm−1) and two orders higher than that of the corresponding r-TiO2(8.04 × 10−6S cm−1). The activation energies below 0.35 eV for all samples suggest that the proton conduction occurred through the Grotthuss mechanism. The differences in the structural arrangement in each crystal phase of TiO2, which is responsible for the water adsorption ability, can be attributed to the current findings of different proton conductivity.We demonstrate that the specific structural arrangement of atoms in the different crystalline phases of TiO2polymorph have strong influence on their proton conduction behavior. At room temperature and 90% relative humidity, brookite-TiO2shows a high proton conductivity of 3.04 × 10−3S cm−1which is almost one order and two orders higher than that of anatase-TiO2and rutile-TiO2, respectively.

Herein we report the mass-production of Cl-doped graphene nanodots through the implementation of pulsed plasma on graphite rod in CHCl3medium. The Cl-doped graphene shows the band gap, which is assigned as p-type semiconductor by kelvin probe force microscopy (KPFM) measurement. The current findings revealed not only the semiconducting nano graphene with significant Cl insertion through pulsed plasma method but also opened a facile route for mass production of elemental doped 2-D layer materials using a wide range of organic solvent.We synthesized the semiconducting Cl-doped nano graphene dots and some other chlorinated carbon derivatives including hexachlorobenzene through exfoliate the graphite rod by the implementation of pulsed plasma in organic solvent. We propose that the current method of generating semiconducting Cl doped graphene materials can be a facile route for the insertion of the foreign elements with a wide range of organic solvent.

This study focuses on designing a laboratory learning program for a high school chemistry course in which students could discover the fundamental principles of Hess’s law via stepwise inquiry. By exploring the chemical properties of common desiccants, mainly those that were reactive in water, students were introduced to the exothermic reaction of CaO(s) with H2O(l) as a heating agent. Due to the difficulties associated with directly measuring the heat of reaction for CaO(s) with H2O(l), the heats of reaction for CaO(s) with HCl(aq) and Ca(OH)2(s) with HCl(aq) were measured. Students could find the most appropriate experimental procedures through discussion in each group and subsequently establish a protocol in the class. The heats of reaction determined by students’ experiments closely corresponded to those calculated using the thermodynamic database. Using the experimental values obtained for the reactions of CaO(s) with HCl(aq) and Ca(OH)2(s) with HCl(aq), students could discover the relationship that existed among the heats of reaction for CaO(s) with H2O(l), CaO(s) with HCl(aq), and Ca(OH)2(s) with HCl(aq) by drawing an energy diagram and making the relevant thermochemical calculations.

The impact that product gas in the reaction atmosphere has on the kinetics of the thermal decomposition of inorganic solids is an outstanding issue that requires a solution to understand the reactions in a solid–gas system. Among a variety of kinetic phenomena induced by atmospheric gas, the restraining effect of the overall reaction rate with increasing partial pressure of the product gas in the reaction atmosphere is the most widely observed phenomenon. In this study, we describe the universal kinetics of the thermal decomposition of solids over different temperatures and partial pressures of the gas, as exemplified by the thermal decomposition of Cu(OH)2. Universal kinetic descriptions were enabled by introducing an accommodation function, with respect to atmospheric water vapor pressure, into the fundamental kinetic equation for solid-state reactions. The thermoanalytical curves as measured systematically under different temperatures and water vapor pressure conditions were kinetically analyzed in a step-by-step manner to attain kinetic modeling of the physico-geometrical consecutive process that comprises the induction period, surface reaction, and phase boundary-controlled reaction. The impact that atmospheric water vapor has on the kinetics of each physico-geometrical reaction step was separately evaluated using the universal kinetic approach.

•HSCs can be separated based on high or low mitochondrial mass.•Higher mitochondrial mass is associated with quiescence and greater reconstitution capacity of HSCs.

We have investigated the crystalline and electronic properties of group-IV semiconductor alloy thin films of Ge1[?]xSnx and Ge1[?]x[?]ySixSny. These semiconductor materials promise effective energy band engineering with type-I band alignment. Also, we have investigated the optoelectronic properties of Ge1[?]x[?]ySixSny/Ge1[?]xSnx/Ge1[?]x[?]ySixSny double heterostructure with measuring photoluminescence spectroscopy.

This study focused on the kinetics and mechanisms of the thermal decomposition of Cu(OH)2as a potential processing route to produce CuO nanoparticles. The physico-geometric reaction behaviors were studied using available physicochemical techniques and microscopic observation. The kinetic modeling of the reaction process to produce CuO nanoparticles was examined via the kinetic analysis of the mass-loss data recorded under different heating conditions. The reaction exhibited specific physico-geometric kinetic characteristics, including an evident induction period, a subsequent sigmoidal mass-loss behavior under isothermal conditions, and a long-lasting reaction tail under linearly increasing temperature conditions. During the first mass-loss step characterized by the sigmoidal mass-loss behavior, the crystallite size of the produced CuO was constant, and the specific surface area increased systematically. The second mass-loss step during the reaction tail was accompanied by the crystal growth of CuO. Therefore, the end of the first mass-loss step was the most efficient reaction stage to obtain CuO nanoparticles. The overall kinetic process that reaches this reaction stage was successfully demonstrated as consecutive physico-geometric processes comprising the induction period, surface reaction, and one-dimensional phase boundary-controlled reaction, providing the kinetic parameters for each component step.

Blood flow regulation in pancreatic islets is critical for function but poorly understood. Here, we establish an in vivo imaging platform in a non-human primate where islets transplanted autologously into the anterior chamber of the eye are monitored non-invasively and longitudinally at single-cell resolution. Engrafted islets were vascularized and innervated and maintained the cytoarchitecture of in situ islets in the pancreas. Blood flow velocity in the engrafted islets was not affected by increasing blood glucose levels and/or the GLP-1R agonist liraglutide. However, islet blood flow was dynamic in nature and fluctuated in various capillaries. This was associated with vasoconstriction events resembling a sphincter-like action, most likely regulated by adrenergic signaling. These observations suggest a mechanism in primate islets that diverts blood flow to cell regions with higher metabolic demand. The described imaging technology applied in non-human primate islets may contribute to a better understanding of human islet pathophysiology.

Studying blood microcirculation is vital for gaining insights into vascular diseases. Blood flow imaging in deep tissue is currently achieved by acute administration of fluorescent dyes in the blood plasma. This is an invasive process, and the plasma fluorescence decreases within an hour of administration. Here, we report an approach for the longitudinal study of vasculature. Using a single intraperitoneal or intravenous administration of viral vectors, we express fluorescent secretory albumin-fusion proteins in the liver to chronically label the blood circulation in mice. This approach allows for longitudinal observation of circulation from 2 weeks to over 4 months after vector administration. We demonstrate the chronic assessment of vascular functions including functional hyperemia and vascular plasticity in micro- and mesoscopic scales. This genetic plasma labeling approach represents a versatile and cost-effective method for the chronic investigation of vasculature functions across the body in health and disease animal models.

The influence of interfacial oxygen (O) and carbon (C) at the SiGe epi/Si interface on misfit dislocation generation and their impact on embedded SiGe device performance were studied. It is found that the interfacial O and C increased the dislocation nuclei, and degraded the channel hole mobility, resulting in the degradation of its device performance. We concluded that it is indispensable to realize not only the low temperature SiGe growth but also the low temperature in-situ precleaning to improve device performance. By using the low temperature SiGe process at 550{degree sign} C including in-situ precleaning and SiGe growth, high device performance such as saturation drain current (Ion) of 765 uA/um were achieved at off current (Ioff) of 100 nA/um at drain bias (VDD) = 1.0 V by suppressing of dislocation generation.

We investigated the photoluminescence (PL) properties of heavily Sb doped n+-Ge1-xSnxlayers and demonstrated the formation of a double heterostructure (DHS) for the n+-Ge1-xSnxactive layer. A single PL peak was observed for n+-Ge1-xSnxlayers thicker than 80 nm with increasing the Sb concentration up to 1020cm-3, attributed to the superior crystallinity and pseudo-direct bandgap transition mechanism, while a 15 nm thick n+-Ge1-xSnxlayer did not exhibit PL signals. A favorable heterostructure for n+-Ge1-xSnxis proposed from the viewpoint of the increased valence band offset (?Ev) using n-SiyGe1-yas the cladding layer. We demonstrated the formation of an n-SiyGe1-y(15 nm)/n+-Ge1-xSnx(15 nm)/n-SiyGe1-y(15 nm) DHS with a superior crystallinity and high PL peak intensity comparable to that of a thick n+-Ge1-xSnx. We discuss the reasons for the PL performance improvement by forming the DHS, including the sufficient carrier confinement and the suppression of surface recombination.

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Changes in the expression of cell adhesion molecule and albumin genes were investigated in primary cultures of rat hepatocytes with and without poly- N-p-vinylbenzyl-D-lactonamide (PVLA) coating of the dishes. In PVLA-coated cultures, hepatocytes aggregated into spheroids and expressed liver cadherin and albumin mRNAs at higher levels. In uncoated cultures, hepatocytes revealed low levels of cadherin and albumin mRNAs, but higher levels of integrin α-1 mRNA. The changes in mRNA levels of liver cadherin and integrin α-1 coordinated well with those in spheroid and monolayer formation of hepatocytes, respectively. These results suggest that, in the PVLA-coated culture, hepatocytes expressed cadherin at higher levels to promote cell–cell adhesion and further maintain the differentiated function, such as albumin secretion, for prolonged times.

Abstract: Sodium α-sulfonated, fatty acid polyethylene glycol monoesters [C m H2m+1CH(SO3Na)COO(C2H4O) n H] and diesters [C m H2m+1CH(SO3Na)COO(C2H4O) n COCH(SO3Na)C m H2m+1], wherem=10–16 andn=1–35, were prepared by esterification of α-sulfonated, fatty acids with polyethylene glycols, followed by neutralization with NaOH. Crude products were purified by reversed-phase column chromatography on an octadecyl-modified silica gel. Characteristic solution behavior of these α-sulfonated fatty acid esters was, examined, and the following features were observed. All monoesters prepared in this work had Krafft points below 0C and also possessed good calcium stabilities. Critical micelle concentrations of the monoesters increased monotonously, as a rule, with an increase in the number of oxyethylene units. These results suggest that the polyethylene glycol residue of the monoester behaves as a hydrophile. On the other hand, diesters possessed high water solubility, low foamability, and critical micelle concentrations that were lower by a factor of ten compared to those of the monoesters.

A base-induced rearrangement involving a 1,2-shift of a phosphono group from carbon to carbon was found in 2-halo-substituted 1-aminoethane-1-1-diphosphonic acids. In 2,2-dichloro-substituted 1-aminoethane-1,1-diphosphonic acid, each of the geminal phosphono groups underwent a 1,2-shift and an elimination, respectively, to give phosphonoacetic acid.

Biological Monitoring of Inorganic Mercury in Workers in a Fluorescent Lamp Plant. Masako Iden, et al.Matsushita Electronics Corp., Okayama Factory—The level of mercury in urine is measured as an exposure monitoring of mercury, and the activity of urinary N‐acetyl‐β‐D‐glucosaminidase (NAG) is used as an index of adverse effects of mercury on human kidneys. Here we examined the validity of these procedures by comparing the urinary total mercury (U‐Hg) level and NAG activity in both 75 male workers exposed to inorganic mercury and age‐matched unexposed male workers in a fluorescent lamp plant. To investigate factors affecting the levels of U‐Hg, 12 items were selected in relation to oral intake and excretion of mercury: consumption of 1) soft drink, 2) coffee or tea, 3) milk and 4) alcohol; 5) habit of drinking tap water at the work place; frequency of 6) eating fish and 7) alcohol intake; 8) smoking; 9) use of dental amalgam; 10) eating of home grown rice; 11) exercise habit and 12) age. The U‐Hg level and NAG activity were adjusted by creatinine levels. Personal exposure levels of inorganic mercury in air (A‐Hg) and the U‐Hg level correlated well (p< 0.001) in the exposed group but neither the exposed nor unexposed group showed a correlation between the U‐Hg level and NAG activity. Although the mean level of U‐Hg in the exposed group was higher than that in the unexposed (p<0.001), no difference was observed in the mean level of NAG activity. A multiple regression analysis followed by a one‐way ANOVA revealed that only the frequency of eating fish per week contributed to increase the level of U‐Hg. The results suggest that oral intake of mercury from fish is a possible confounding factor in the exposure monitoring of inorganic mercury in the work place.

Biological Monitoring of Inorganic Mercury in Workers in a Fluorescent Lamp Plant. Masako Iden, et al.Matsushita Electronics Corp., Okayama Factory—The level of mercury in urine is measured as an exposure monitoring of mercury, and the activity of urinary N-acetyl-ß-D-glucosaminidase (NAG) is used as an index of adverse effects of mercury on human kidneys. Here we examined the validity of these procedures by comparing the urinary total mercury (U-Hg) level and NAG activity in both 75 male workers exposed to inorganic mercury and age-matched unexposed male workers in a fluorescent lamp plant. To investigate factors affecting the levels of U-Hg, 12 items were selected in relation to oral intake and excretion of mercury: consumption of 1) soft drink, 2) coffee or tea, 3) milk and 4) alcohol; 5) habit of drinking tap water at the work place; frequency of 6) eating fish and 7) alcohol intake; 8) smoking; 9) use of dental amalgam; 10) eating of home grown rice; 11) exercise habit and 12) age. The U-Hg level and NAG activity were adjusted by creatinine levels. Personal exposure levels of inorganic mercury in air (A-Hg) and the U-Hg level correlated well (p<0.001) in the exposed group but neither the exposed nor unexposed group showed a correlation between the U-Hg level and NAG activity. Although the mean level of U-Hg in the exposed group was higher than that in the unexposed (p<0.001), no difference was observed in the mean level of NAG activity. A multiple regression analysis followed by a one-way ANOVA revealed that only the frequency of eating fish per week contributed to increase the level of U-Hg. The results suggest that oral intake of mercury from fish is a possible confounding factor in the exposure monitoring of inorganic mercury in the work place.

Spectroscopic nonequivalence between the geminal PO(OH)2groups of some aminodiphosphonic acids with a highly electronegative substituent at 2-position of 1-aminoethylidenediphosphonic acid was found by 1H NMR measurement in D2O. This may result from the formation of an inner salt between amino group and one of the PO(OH)2groups.

Sodium a-sulfonated, fatty acid polyethylene glycol monoesters [CmH2m+1CH(SO3Na)COO(C2H4O)nH] and diesters [CmH2m+1CH(SO3Na)COO(C2H4O)nCOCH(SO3Na)CmH2m+1], wherem=10–16 andn=1–35, were prepared by esterification of a-sulfonated, fatty acids with polyethylene glycols, followed by neutralization with NaOH. Crude products were purified by reversed-phase column chromatography on an octadecyl-modified silica gel. Characteristic solution behavior of these a-sulfonated fatty acid esters was, examined, and the following features were observed. All monoesters prepared in this work had Krafft points below 0°C and also possessed good calcium stabilities. Critical micelle concentrations of the monoesters increased monotonously, as a rule, with an increase in the number of oxyethylene units. These results suggest that the polyethylene glycol residue of the monoester behaves as a hydrophile. On the other hand, diesters possessed high water solubility, low foamability, and critical micelle concentrations that were lower by a factor of ten compared to those of the monoesters.

The thermal decomposition of smithsonite (ZnCO3) was studied to obtain a universal kinetic description of the process applicable to a range of reaction conditions. A synthesized ZnCO3was subjected to thermoanalytical measurements under various heating and atmospheric conditions in a flow of dry N2gas, or N2–CO2or N2–H2O mixed gases. Systematic shifts of the reaction temperature to higher or lower values by the effects of CO2or H2O, respectively, were identified as specific characteristics of the system. With reference to the physicogeometrical kinetic behavior of the reaction in a flow of dry N2gas, the retardation effect of CO2was demonstrated in the scheme of the physicogeometrical consecutive surface reaction (SR) and phase boundary-controlled reaction (PBR). The individual kinetics of SR and PBR were universally described over different CO2partial pressures using an accommodation function (AF) obtained by considering the consecutive elementary steps of SR and PBR. The catalytic effect of water vapor was assumed to result from contributions of water molecules to the consecutive elementary steps of SR and to the crystal growth of the solid product of the reaction (ZnO). An alternative AF derived considering the adsorption of water molecules on solid surfaces allowed us to obtain the universal kinetic description of the thermal decomposition over different water vapor pressures.

1-Dimethylamino-1-methoxy-1-alkenes (ketene O,N-acetals), 1-dimethylamino-1-ethylthio-1-alkenes (ketene S,N-acetals) and 1,1-bis(dimethylamino)ethylene (ketene N,N-acetal) reacted with diethyl phosphite to give the corresponding (E)-diethyl 1-dimethylamino-1-alkenylphosphonates. Although ketene diethylacetal (ketene O,O-acetal) reacted with diethyl phosphite to give diethyl 1,1-diethoxy-1-ethylphosphonate, 1,1-bis(ethylthio)-1-alkenes (ketene S,S-acetals) did not react with diethyl phosphite.

We have investigated the crystalline and electronic properties of group-IV semiconductor alloy thin films of Ge1−xSnxand Ge1−x−ySixSny. These semiconductor materials promise effective energy band engineering with type-I band alignment. Also, we have investigated the optoelectronic properties of Ge1−x−ySixSny/Ge1−xSnx/Ge1−x−ySixSnydouble heterostructure with measuring photoluminescence spectroscopy.

We have investigated the formation and optoelectronic properties of strain relaxed Ge1[?]x[?]y Si x Sn y /Ge1[?]x Sn x /Ge1[?]x[?]y Si x Sn y double heterostructures on ion-implanted Ge substrates. The strain relaxation of Ge1[?]x[?]y Si x Sn y and Ge1[?]x Sn x epitaxial layers was achieved using an ion-implanted Ge substrate. The maximal degree of strain relaxation (DSR) of the Ge1[?]x Sn x layers was evaluated to be 46%. In addition, we obtained a sharp and strong peak in the photoluminescence (PL) spectra from the sample with a DSR of 46%, while no strong peak was detected from a sample with a smaller DSR (22%). From the theoretical calculation of the energy band structure and the measurement temperature dependence of the PL intensity, the sharp and strong peak can be explained by the transition from an indirect to direct bandgap semiconductor due to the increase of the DSR and a concomitant increase of the G-valley electron population. Moreover, the PL intensity increases by the improvement of the crystallinity by a post deposition annealing process.

Glucose starvation triggers cell death through a calcium-dependent signaling pathway independently of cell energy metabolism.

Chloroacetanilide and p-methylchloroacetanilide reacted with phosphoryl chloride to give 2-chloromethyl-3-chloro-4-anilinoquinoline and 2-chloromethyl-3-chloro-4-(p-toluidino)-6-methylquinoline respectively. In the case of propionanilide, 2-ethyl-3-methyl-4-anilinoquinoline was obtained when the reaction was carried out at 20–30 °C. On the other hand, when the reaction temperature was raised to 80–100 °C, N-(1-chloro-1-propenyl)-N,N'-diphenylacetamidine was obtained.

We report our project on numerical study of gluon propagators on a parallel vector computer, Numerical Wind Tunnel (NWT). First we briefly discuss the performance of NWT as a QCD machine. Then we introduce the gauge fixing force a la Zwanziger on a lattice, which we believe is the only algorithm to prevent Gribov copies. We show our numerical data on a 483 ×64 lattice at β = 6.8 which cannot be fit by free massless propagators, but may be compatible with Gribov prediction.

The influence of interfacial oxygen (O) and carbon (C) at the SiGe epi/Si interface on misfit dislocation generation and their impact on embedded SiGe device performance were studied. It is found that the interfacial O and C increased the dislocation nuclei, and degraded the channel hole mobility, resulting in the degradation of its device performance. We concluded that it is indispensable to realize not only the low temperature SiGe growth but also the low temperature in-situ precleaning to improve device performance. By using the low temperature SiGe process at 550{degree sign} C including in-situ precleaning and SiGe growth, high device performance such as saturation drain current (Ion) of 765 μA/μm were achieved at off current (Ioff) of 100 nA/μm at drain bias (VDD) = 1.0 V by suppressing of dislocation generation.

BACKGROUND: Implantation of self-expanding metallic stents is anestablished palliation therapy for malignant biliary strictures. Wedesigned the polyurethane covered metallic stents and treated fiftypatients with them. We confirmed many merit of covered stents, but severalcomplications after the stent implantation remain still now. Recentlywe newly modified covered metallic stents to avoid the stent migration. AIM: We studied the clinical effectiveness of the covered metallic stents and the modified covered stents compared with the uncoverd stents. PATIENTS AND METHODS: Sixty eight patients (36 males, 32 females, mean age 73) with malignant biliary strictures have been treated with polyurethane-covered metallic stents (n= 50), modified covered stents (n= 8) and uncovered metallic stents (n= 10).We made the polyurethane membrane , using solid polyurethane and a glass tube and covered it outside the stent. We originally designed polyurethane membrane with the thickness of 0.05mm. Recently we modified the covered stent: i.e. we put the polyurethane membrane inside the stent.We treated twenty eight patients transhepaticaly and thirty eight endoscopically. For the hilar strictures two fully covered setnts were implanted like Y shape, using percutaneous transhepatic cholangioscopy. RESULTS: Stent placement was technically successful in all patients. None of procedure-related complication was confirmed. Patency period was 7.4 months of uncovered group and 11.84 months of covered group in the longer follow-up period than six months. Stent obstruction due to tumor ingrowth occurred in five ptients (50%) of uncovered metallic stents with a median time to obstruction of 24 weeks and none of covered group except two cases with tumor ingrowth due to technical immaturity. Stent migration was cofirmed in four patients (8%) of fully covered group but not confirmed in the patients treated with the modified stents. Tumor overgrowth was confirmed in six patients (12%) of covered group because of short length of the stents. Mucosal hyperplasia was confirmed in one patient (2%) of partially covered group. CONCLUSION:We think that the covered and modified covered metallic stents are good alternatives for palliating malignant biliary strictures.We believe the best stent will be newly modified covered stent.

N,N-Dialkylformamides reacted with phosphorus trichloride or phosphorus tribromide to give the corresponding dialkylaminomethylenediphosphonic acids.