Search

Metal halide perovskites have been extensively investigated for application in light-emitting diodes (LEDs) because their optical band gap can be adjusted via the alteration of their halide-ion composition. However, the performance of metal halide perovskite LEDs (PeLEDs) is limited by halide-vacancy-induced surface defects. Therefore, mixed-halide perovskites were introduced to prevent the formation of halide vacancies on the perovskite surface. However, typical CsPbBrxI3‑x-based PeLEDs exhibit ion migration under an electrical field, which results in phase segregation and the deterioration of the device performance. In this study, to overcome these obstacles, PeLEDs based on CsPbBrxI3-x–multi-ligands–KBr films were introduced. The use of multi-ligands could facilitate the recombination of excitons and stabilization of the α-phase perovskite crystals. Moreover, the KBr not only prevented the formation of halide vacancies by interaction with excess halide ions but also improved the surface coverage. Thus, an optimized film-based—CsPbBrxI3-x–multi-ligand (70% NMABr0.7I0.3–15% N,N-dimethyl-1,3-propanediammonium bromide–15% 1,3-propanediammonium bromide)–KBr (0.03 M)—PeLED was fabricated, which had a current density of 5.1 mA/cm2, current efficiency of 3.2 cd/A, luminance of 743.2 cd/m2, and an external quantum efficiency of 10.2%. Moreover, this PeLED exhibited a low turn-on voltage (1.6 V) with pure-red emission.

Attackers use the openness of the Internet to facilitate the dissemination of malware. Their attempts to infect target systems via the Web have increased with time and are unlikely to abate. In response to this threat, we present an automated, low-interaction malicious webpage detector, WebMon , that identifies invasive roots in Web resources loaded from WebKit2-based browsers using machine learning and YARA signatures. WebMon effectively detects hidden exploit codes by tracing linked URLs to confirm whether the relevant websites are malicious. WebMon detects a variety of attacks by running 250 containers simultaneously. In this configuration, the proposed model yields a detection rate of 98%, and is 7.6 times faster (with a container) than previously proposed models. Most importantly, WebMon ’s focus on extracting malicious paths in a domain is a novel approach that has not been explored in previous studies.

This paper studies the deployment of next generation Internet, which will serve as crucial infrastructure for basic network services for social connections as well as premium network services. Service productions and consumptions take different forms across these service types. For example, their network externalities are one of the distinct characteristics of social connections, while premium network services contribute to investment in network assets beyond a base level, resulting in extra capital stock. This multifaceted nature of the next generation Internet raises policy issues regarding network investment and net neutrality. This study aims at developing a dynamic model with a representative user whose preferences are differentiated by service types. The fraction of usage of social connections and the level of the extra capital stock are state variables representing system behavior. My analyses identify not only interior but also boundary equilibria under various scenarios about the relationships between the relative productivity and cost of social connectedness and premium network services. The policy implications from the analysis include the effects of rapid technological development on network obsolescence, which may tip the market in favor of social connections. Net neutrality may lead to unintended consequences though, due to its effects on the sources for network investment.

Rural labor force has been gradually decreased due to decreasing of farm population and increasing of aging population. Therefore, the study of unmanned technology is needed to overcome labor shortage in agriculture. These days most research on unmanned autonomous tractors has been carried out through field tests; however, field tests require lots of cost and time. Therefore, in this study, a simulation platform model was developed for the driving performance evaluation of unmanned tractors. Simulation was conducted by using analysis tools which used widely in the testing of unmanned vehicle simulation and vehicle dynamic behavior. Tractor model used in the simulation was a 71 kW-class (L7040, LS Mtron, Korea). Simulation was conducted to evaluate autonomous driving performance based on driving paths and field conditions. The results of the simulation showed that larger values in the error of tire force, tire kinematics, and slip were observed at the curved path than at the straight path. In the future study, it is determined that need for a method for reducing a positioning error through control algorithm developed at the curved paths.

This study explored the influence of using copper slag as an alternative sand for producing cement mortar bricks and its effect on γ-ray attenuation property, strength, and consistency of mortar. The linear attenuation coefficients and mass attenuation coefficients were experimentally determined for mortar mixtures using the 60Co and 137Cs gamma-ray source, and, using the Phy-X program, attenuation parameters were theoretically calculated in 1 keV–100 GeV. Sample bricks with added copper slag were produced and tested. In the results, the added copper slag was greatly beneficial for increasing the flowability and strength of mortar, and, given all the results of attenuation parameters, the use of copper slag as aggregates was notably advantageous compared to silica sands for gamma-ray attenuation mainly due to the high Fe quantity in copper slag. The trial brick specimens using 100 wt% copper slag replacement for sand not only satisfied all requirements of cement brick in the Korean standard (KS) F 4004, but also the TCLP regulation.

The robot sector in many countries has thrived recently thanks to government supports and innovations in various industries. This study, using the patent database to define the robot sector, reconfigures IO (Input-Output) data to analyze the relationships among various sectors. In particular, we consider the internal description of the robot sector (mesoscopic view) as well as the relationship between the robot and the non-robot sectors (macroscopic view), so that we can not only understand robot ecosystems in various dimensions, but also develop policy insights. For the sake of systematic analysis of the intra- and inter-sector relations as well as the meso-macro links, this study constructs network models and employs several network measures. Our model and analysis present a good case study of Korea to understand the nature of the robot sector and the overall business ecosystem there. This novel approach also contributes to finding out a promising path that leverages the strengths of intra-sector relations and spreads the impact of the robot sector across the macro relations.

This study investigated the role of crystallinity of added nanometer-sized Al2O3 (nano-alumina) (i.e., poorly crystalline nano-alumina (γ-alumina) vs. crystalline nano-alumina (α-alumina)) and the interaction of nano-aluminas with added gypsum in the CaO-activated ground granulated blast furnace slag (GGBFS) binder system. In the results, the use of γ-alumina evidently increased the dissolution degree of silicon (Si) from GGBFS regardless of adding gypsum, which was the main ingredient of calcium silicate hydrate (C-S-H), and thus led to a noticeable increase of C-S-H. However, the sole use of α-alumina without added gypsum barely affected the C-S-H formation, although the added α-alumina alongside gypsum also had a similar effect on the dissolution of Si. In addition, due to the amorphous nature of γ-alumina, the dissolution of γ-alumina was faster than that of α-alumina. Thus, the use of γ-alumina produced ettringite at the faster rate, as well achieving the greater and faster strength increase, although the added α-alumina was also slightly beneficial in accelerating the formation of ettringite. Thus, overall, the use of γ-alumina was significantly more advantageous in improving strength by increasing the quantities of reaction products (C-S-H and/or ettringite) than that of α-alumina.

Background: The RV144 phase 3 vaccine trial in Thailand demonstrated that ALVAC-HIV (vCP1521) and AIDSVAX® B/E administration over six months resulted in a 31% efficacy in preventing HIV acquisition. Subsequent boosting of RV144 vaccine recipients 6 to 8 years later improved the magnitude and quality of immune responses, expanding subdominant memory B cells. Methods: RV306 is a double-blind, placebo-controlled, randomized clinical trial of the primary RV144 vaccine series with additional AIDSVAX® B/E with or without ALVAC-HIV boosting at months 12, 15, or 18 in healthy volunteers. Findings: Late boosting was safe, and improved antigen-specific plasma IgG responses to HIV-1 envelope and the first and second variable loops (V1V2), an inverse correlate of HIV risk in RV144, without increasing HIV-specific plasma IgA, a direct correlate of risk. Late boosting improved Tier 1 neutralization and HIV-1 envelope-specific CD4+ T cell polyfunctionality, an independent correlate contributing to RV144 vaccine efficacy. Late boosting was also required to maintain antigen-specific CD4+ T cell proliferation. Interestingly, increasing the interval between priming and boosting improved several humoral and cellular immune responses. Interpretation: Taken together, these results suggest that additional boosting of the RV144 regimen with longer intervals between the primary vaccination series and late boost improved immune responses and may improve the efficacy of preventing HIV acquisition. Funding Statement: Cooperative Agreement # W81XWH-18-2-0040 in collaboration with the US Army and DAIDS/NIAID/NIH. Declaration of Interests: J. T., and C. D. are employees of Sanofi Pasteur. S.P. was an employee of Sanofi Pasteur during the conduct of this study and analysis. F. S. is an employee of Global Solutions for Infectious Diseases. All other authors report no potential conflicts. The opinions expressed herein are those of the authors and do not represent the official position of the US Army or the Department of Defense. Trade names are used for identification purposes only and do not imply endorsement. Ethics Approval Statement: The study was approved by ethical review boards at the Walter Reed Army Institute of Research, Thai Ministry of Public Health, Royal Thai Army Medical Department, Faculty of Tropical Medicine, Mahidol University, Chiang Mai University, and Chulalongkorn University Faculty of Medicine. This study was conducted in accordance with Good Participatory Practice principles.

The ionic crystals of perovskites have been widely studied for light-emitting diodes (LEDs) applications because their optical bandgap can be adjusted by changing the composition of the halide anions. However, the small ion size of Cs+ in inorganic perovskite causes poor crystallinity and a low exciton binding energy owing to the inherent defects in the bulk perovskite, which hinder the luminescence efficiency of perovskite LEDs (PeLEDs). Moreover, cesium lead iodide (CsPbI3), which is studied as an emitter of red PeLEDs, is not only required to be heat-treated at a high temperature of 300 °C for phase stabilization but also vulnerable to O2 and moisture in the air. To solve these problems, high performance red PeLED based on CsPbBr0.6I2.4 perovskites were fabricated by using poly(2-ethyl-2-oxazoline) (PEOXA) as a hydrophilic polymer. This method reduced the transition temperature of CsPbBr0.6I2.4 from the δ–phase (tilted octahedral) to the α–phase (cubic) and stabilized the perovskite phase. Thus, an exceptionally efficient and stable PeLED based on a CsPbBr0.6I2.4–45% PEOXA film with a maximum external quantum efficiency (EQE) of 5.4%, luminance of 201.2 cd/m2, and current efficiency (CE) of 3.2 cd/A was fabricated. Moreover, the PeLED exhibited a low turn-on voltage (1.5 V) and CIE coordinates of (0.726, 0.274), with pure-red emission.

Escherichia coli cells with autodisplayed Z-domains have been used for immunoassays of specific target analytes. In this study, a magnetite suspension was used for the washing step in immunoassays of E. coli cells with autodisplayed Z-domains. This approach enhanced the washing conditions for these immunoassays by determining (1) the optimal concentration of the magnetite suspension, (2) the capacity of the magnetite suspension-based washing method to recover E. coli cells, and (3) the level at which the activity of autodisplayed Z-domains is maintained. In immunoassays of C-reactive protein (CRP), the immunoassay incorporating the magnetite suspension-based washing method showed a sensitivity and limit of detection considerably higher than those of the conventional centrifugation-based washing method. The results indicated that immunoassays incorporating the magnetite suspension-based washing method are effective for medical diagnoses based on CRP assay.

A simple strategy, based on the Al-doped ZnO nanorods (NRs), to get an antireflective, self-cleanable and electrical conductive window layer for the thin film solar cell was demonstrated. The length and diameter of Al-doped ZnO NRs were optimized by controlling Al precursor concentration and growth time and an average reflectance of 2.9% was achieved. Al-doped ZnO NRs simultaneously having the rugged surface morphology with the micrometer- and nanometer-scale roughness also exhibited superhydrophobicity and extremely small water contact angle (WCA) hysteresis below Δ1° after treatment of hydrophobic self-assembled monolayer (SAM). Finally, in spite of the existence of the SAM, the enhancement of the electrical contact with silver from Schottky to Ohmic for various Al doping concentrations was confirmed. Self-cleanable and electrically conductive antireflecting layer introduced in this work would be expected to increase photovoltaic efficiency in a thin film solar cell.

The Z-domain has the potential to control the orientation of immobilized antibodies because of its binding affinity to the Fc regions of antibodies (IgGs). In this work, Z-domains were autodisplayed on the outer membrane (OM) of Escherichia coli. OM particles were isolated and coated onto microbeads with positive, neutral, or negative surface charges. Other conditions such as incubation time and initial OM concentration were also optimized for the OM coating to obtain maximum antibody-binding. Using three kinds of model proteins with different isoelectric points (pI), streptavidin (pI = 5, negative charge at pH 7), horseradish peroxidase (pI = 7, neutral charge at pH 7), and avidin (pI = 10, positive charge at pH 7), protein immobilization onto the microbeads was carried out through physical adsorption and electrostatic interactions. Using fluorescently labeled antibodies and fluorescence-activated cell sorting, it was determined that the neutral and the positively charged microbeads effectively bound antibodies while minimizing non-specific protein binding. The OM-coated microbeads with autodisplayed Z-domains were applied to C-reactive protein immunoassay. This immunoassay achieved 5-fold improved sensitivity compared to conventional immunoassay based on physical adsorption of antibodies at the cutoff concentration of medical diagnosis of inflammatory diseases (1000 ng/ml) and cardiovascular diseases (200 ng/ml).

Recently, the combined use of calcium oxide (CaO) and calcium formate (Ca(HCOO)2) has been proposed as an alternative activator for ground granulated blast furnace slag (GGBFS) (referred to as CaO-Ca(HCOO)2-activated GGBFS system). However, this clinker-free binder system produces calcium aluminate hydrate (C2AH8), generally leading to the degradation of cementitious binder systems by its conversion to other phases. Thus, in this study, attempts to remove C2AH8 from this system without losing the strength are suggested by the use of two additives (i.e., calcium sulfate (CaSO4) and calcium nitrate (Ca(NO3)2), respectively). Results revealed that the above-mentioned additives completely remove C2AH8 in the initial curing stage via its conversion to ettringite or NO3- and NO2-AFm, respectively. In addition, the additives reduced the extent of the total shrinkage and the standard deviation of strength results of triplicate samples. However, CaSO4 exerted a beneficial effect on the strength, while Ca(NO3)2 exerted a marginal or detrimental effect on the strength. Therefore, this study suggested a new mixture form of an activator, comprising CaO, Ca(HCOO)2, and CaSO4, to activate GGBFS for maintaining strength without the conversion issue of C2AH8.

In this study, a new clinker-free white binder that exhibits whiteness comparable to that of white Portland cement was proposed by investigating the effects of an activator (i.e., CaO vs. NaOH) and added TiO2 (i.e., anatase vs. rutile, dosage) on the surface colors of activated ground granulated blast furnace slag (GGBFS). Overall, compared to the type or dosage of TiO2, the type of activator exhibited a more pronounced effect on the surface color although TiO2 was considerably beneficial for increasing whiteness. As determined by ASTM E313, the results revealed that all NaOH-activated samples are neither “white” nor “near white,” even with the highest dosage of the added TiO2, while all CaO-activated samples were nearly white even without the added TiO2. In addition, NaOH and CaO produced different tints (i.e., green by NaOH and red by CaO activation, respectively) regardless of the presence of TiO2. In CaO activation, rutile was more effective than anatase in improving all color indices and whiteness; however, in NaOH activation, the addition of anatase was better for reducing tints of yellowness and greenness. The whitest sample was obtained, which was whiter than white Portland cement on all days, by the addition of 16% rutile in CaO activation; however, if strength was considered in addition to whiteness, the same system with 4 wt% rutile would be the best candidate mixture.

Like other technologies that shape modern society, the Internet is continually evolving. The next-generation Internet, based on 5G and beyond, will be very different from the early Internet, and will provide an entirely new social and technological environment. For the Internet to function effectively as a core medium in the hyper-connected society of Industry 4.0, it is necessary to clarify the multifaceted nature of the Internet. Also, our community needs to maintain a balanced perspective between the dual characteristics of the Internet – basic connections and advanced services. In this regard, desirable network policy should maximize the network externality in basic social connections while developing advanced network services for Industry 4.0. In particular, since the social demand for the latter will increase with 5G, so that Industry 4.0 is more sophisticated, it is essential to establish a socially-agreed upon system to ensure effective investment in network assets.

This study provides a model that captures the essential features of the social commerce business. The model focuses on the relationship between key decision issues, such as marketing expenditures and the revenue streams that are created. As more social commerce businesses enter the marketplace, they are faced with fierce competition, which may lead to sharp increases in marketing and advertising expenditures. This type of competition may lead the industry away from its optimal development path, and at worst, toward a disruption of the entire industry. Another goal of this study is to examine the possibility that the tragedy of commons may occur in the industry. The basic analysis presents Nash equilibrium results with homogeneous and heterogeneous players. The analysis further specifies the conditions that the tragedy of commons can occur. I discuss the strategic implications and policy directions that may be able to overcome the shortcomings of current business model, and help the industry to achieve more sustainable development.

SummaryAutophagy is of increasing interest as a target for cancer therapy. We find that leucine deprivation causes the caspase-dependent apoptotic death of melanoma cells because it fails to appropriately activate autophagy. Hyperactivation of the RAS-MEK pathway, which is common in melanoma, prevents leucine deprivation from inhibiting mTORC1, the main repressor of autophagy under nutrient-rich conditions. In an in vivo tumor xenograft model, the combination of a leucine-free diet and an autophagy inhibitor synergistically suppresses the growth of human melanoma tumors and triggers widespread apoptosis of the cancer cells. Together, our study represents proof of principle that anticancer effects can be obtained with a combination of autophagy inhibition and strategies to deprive tumors of leucine.

We studied the effect of a novel dipeptidyl peptidase IV (DPP IV) inhibitor, DA-1229, on blood glucose profile and pancreatic β-cell mass in established diabetes after streptozotocin (STZ) treatment. Mice that developed diabetes after administration of STZ 100mg/kg were treated with DA-1229 for 13 weeks. DA-1229 significantly reduced plasma DPP IV activity, and enhanced glucagon-like peptide 1 (GLP-1) levels. In STZ-treated mice fed DA-1229 (STZ-DA), blood glucose levels were significantly lower than those in diabetic mice fed normal chow (STZ-NC). Basal and glucose-stimulated insulin secretion and glucose tolerance assessed by intraperitoneal glucose tolerance test were significantly improved by DA-1229 administration. Volume density of β-cell was significantly increased in STZ-DA mice compared to STZ-NC mice, suggesting that DA-1229-mediated amelioration of established diabetes was due to beneficial effect of DA-1229 on β-cell mass. The number of replicating β-cells and that of scattered small β-cell unit representing β-cell neogenesis were significantly increased in STZ-DA mice compared to STZ-NC mice, explaining increased β-cell mass by DA-1229. The expression of PDX-1, a downstream mediator of GLP-1 action, was increased in islets of STZ-DA mice compared to STZ-NC mice. These results suggest a therapeutic potential of DA-1229 in diabetes, particularly that associated with decreased β-cell mass.

Summary Vacuolar protein sorting 34 (Vps34) complexes, the class III PtdIns3 kinase, specifically phosphorylate the D3 position of PtdIns to produce PtdIns3P. Vps34 is involved in the control of multiple key intracellular membrane trafficking pathways including endocytic sorting and autophagy. In mammalian cells, Vps34 interacts with Beclin 1, an ortholog of Atg6 in yeast, to regulate the production of PtdIns3P and autophagy. We show that Vps34 is phosphorylated on Thr159 by Cdk1, which negatively regulates its interaction with Beclin 1 during mitosis. Cdk5/p25, a neuronal Cdk shown to play a role in Alzheimer's disease, can also phosphorylate Thr159 of Vps34. Phosphorylation of Vps34 on Thr159 inhibits its interaction with Beclin 1. We propose that phosphorylation of Thr159 in Vps34 is a key regulatory mechanism that controls the class III PtdIns3 kinase activity in cell-cycle progression, development, and human diseases including neurodegeneration and cancers.

The APP-processing pathway is a pathological component of Alzheimer's disease (AD), but there is no consensus regarding the physiological functions of APP and its products. Two studies (Nikolaev et al., 2009; Lauren et al., 2009) link the physiological and pathological aspects of APP processing. They show that the APP products, N-APP and Abeta42, are ligands for death receptor 6 and cellular prion protein, respectively, which are important in nervous system development and synaptic suppression.

Summary Aberrant cell-cycle activity and DNA damage are emerging as important pathological components in various neurodegenerative conditions. However, their underlying mechanisms are poorly understood. Here, we show that deregulation of histone deacetylase 1 (HDAC1) activity by p25/Cdk5 induces aberrant cell-cycle activity and double-strand DNA breaks leading to neurotoxicity. In a transgenic model for neurodegeneration, p25/Cdk5 activity elicited cell-cycle activity and double-strand DNA breaks that preceded neuronal death. Inhibition of HDAC1 activity by p25/Cdk5 was identified as an underlying mechanism for these events, and HDAC1 gain of function provided potent protection against DNA damage and neurotoxicity in cultured neurons and an in vivo model for ischemia. Our findings outline a pathological signaling pathway illustrating the importance of maintaining HDAC1 activity in the adult neuron. This pathway constitutes a molecular link between aberrant cell-cycle activity and DNA damage and is a potential target for therapeutics against diseases and conditions involving neuronal death.

Objective With growing demand for health information and rapid development of information technology, health information websites are emerging as the most effective media to meet the public's needs for health information. This article is intended to offer a technical view on the design and operations of health information websites. Along this line, employed here is the Technology Acceptance Model (TAM), which has been widely used to predict user acceptance based on Perceived Ease-of-Use (PEOU) and Perceived Usefulness (PU). Methods We extend the original TAM by including some exogenous variables since it is necessary to understand the role of the antecedents of acceptance constructs when designing an effective health information website for improving user satisfaction. This study focuses on identifying the core functional factors in designing and operating health information websites. Conducted are some multivariate statistical analyses based on data from an extensive survey. Results The results from the structural equation analysis suggest that functional characteristics should be categorized into three groups: one affecting PU and PEOU, another affecting only PEOU, and the other having no direct effect on either PU or PEOU. In particular, ‘usage support' and ‘customization' are two key functional characteristics in the extended TAM framework for health information websites. Conclusion Contrary to expectations, however, the direct effect of PEOU on usage support is hardly observed, which differentiates health information websites from other commercial websites like online shopping malls. As a result, understanding the antecedents of PU takes on more significance.

The mass resolution for the time of flight aerosol mass spectrometer for aerosol component analysis is dependent on the initial direction and energy of the ions. We have found that the shape of the optimum post focusing electric field is nonlinear. The maximum electric potential should be applied to the ions whose initial direction is 90°. To determine the post focusing effects, a laser ablation mass spectrometer was installed. By using this LA-MS, it was found that the average energy distribution of the laser ablated ions was 8 eV. To establish an optimum mass resolution, a time delay and a high voltage are needed. The study results showed that 1500 ns and 3.7 kV, respectively, were the optimum parameters for time delay and voltage for this system. Using these optimized parameters, good resolution between the isotope mass signals of copper was achieved.

Usefulness of the in vitro and in vivo generation of neural precursors from embryonic stem (ES) cells has been widely discussed, but functional recovery in animal models of Parkinson's disease (PD) is not fully understood. The aim of this study was to investigate a transplantation strategy for PD by assessing whether double-transplants in the striatum (ST) and substantia nigra (SN), or ST and subthalamic nucleus (STN) induce functional recovery in 6-hydroxydopamine-lesioned rats. Methamphetamine-induced rotation was significantly reduced by transplantation of mouse ES cell-derived neurons into the ST, but not the STN or SN alone. Double-transplantation was also effective at recovering rotational behavior. Although immunoreactivity for tyrosine hydroxylase (TH) was almost completely lost in the ipsilateral striatum in hemiparkinsonian rats, TH immunoreactivity was detected in transplanted cells and sprouting fibers in the ST, STN and SN. These results suggest that both the involvement of ST as a place of transplantation and the number of ES cell-derived neurons are essential factors for efficacy on hemiparkinsonian behaviors.

We newly developed a sheet-type macroencapsulation device entrapping rat islets from 3% polyvinyl alcohol (PVA) dissolved in Euro-Collins solution containing 10% fetal bovine serum and 5% dimethyl sulfoxide (PVA + EC) using a freezing/thawing technique. The same encapsulation technique but with 3% PVA dissolved only in double-distilled water (PVA) and a culture of free islets were served as controls. After 14-day culture in the CMRL-1066 medium, the islet recovery rate, morphological changes, insulin content, and insulin secretion were evaluated in vitro to prove the feasibility of this method of encapsulation. We also xenotransplanted the device into the peritoneal cavity of diabetic C57BL/6 mice to check its function in vivo. After 1-day culture, the islet recovery rate and insulin content in the PVA group were significantly lower than that in the PVA + EC and free islet groups. After 14-day culture, only the islets in the PVA+EC group maintained a normal morphology and effective insulin secretory response to high glucose while the response was not observed in the PVA group after 1-day culture and no longer observed in the free islets after 7-day culture. After transplantation of rat islets encapsulated in the PVA + EC device to diabetic C57BL/6 mice, nonfasting blood glucose levels showed a rapid decrease from high glucose levels of pre-transplantation, maintaining significantly lower glucose levels during the whole course of study in comparison with the sham-operated group. Our results indicated that this freezing/thawing macroencapsulation technique using 3% PVA + EC was effective for xenotransplantation of islet cells.

Ascospore germlings of Monosporascus cannonballus attached to melon roots were examined with the scanning electron microscope. Results showed that ascospores germinated with one to three germ tubes. Sixty percent of the ascospores germinated with two germ tubes. No germ pores were observed. Instead, germ tubes emerged from a single linear fissure on each ascospore. The largest fissure measured 25 μm in length and 6 μm at its greatest width. Germ tubes of ascospore germlings were firmly anchored to melon roots. However, no structures resembling appressoria were observed. Rather, the tips of germ tubes, upon contact with the epidermis, appeared to have penetrated the epidermis directly. When the germ tube at the point of attachment was dislodged, no infection peg was present at the germ tube tip.

We have studied a possible role of extracellular zinc ion in the activation of p70S6k, which plays an important role in the progression of cells from the G(1) to S phase of the cell cycle. Treatment of Swiss 3T3 cells with zinc sulfate led to the activation and phosphorylation of p70S6k in a dose-dependent manner. The activation of p70S6k by zinc treatment was biphasic, the early phase being at 30 min followed by the late phase at 120 min. The zinc-induced activation of p70S6k was partially inhibited by down-regulation of phorbol 12-myristate 13-acetate-responsive protein kinase C (PKC) by chronic treatment with phorbol 12-myristate 13-acetate, but this was not significant. Moreover, Go6976, a specific calcium-dependent PKC inhibitor, did not significantly inhibit the activation of p70S6k by zinc. These results demonstrate that the zinc-induced activation of p70S6k is not related to PKC. Also, extracellular calcium was not involved in the activation of p70S6k by zinc. Further characterization of the zinc-induced activation of p70S6k using specific inhibitors of the p70S6k signaling pathway, namely rapamycin, wortmannin, and LY294002, showed that zinc acted upstream of mTOR/FRAP/RAFT and phosphatidylinositol 3-kinase (PI3K), because these inhibitors caused the inhibition of zinc-induced p70S6k activity. In addition, Akt, the upstream component of p70S6k, was activated by zinc in a biphasic manner, as was p70S6k. Moreover, dominant interfering alleles of Akt and PDK1 blocked the zinc-induced activation of p70S6k, whereas the lipid kinase activity of PI3K was potently activated by zinc. Taken together, our data suggest that zinc activates p70S6k through the PI3K signaling pathway.