Towards Network Lifetime Enhancement of Resource Constrained IoT Devices in Heterogeneous Wireless Sensor Networks.

The participating nodes in Wireless Sensor Networks (WSNs) are usually resource-constrained in terms of energy consumption, storage capacity, computational capability, and communication range. Energy is one of the major constraints which requires an efficient mechanism that takes into account the energy consumption of nodes to prolong the network lifetime. Particularly in the large scale heterogeneous WSNs, this challenge becomes more critical due to high data collection rate and increased number of transmissions. To this end, clustering is one of the most popular mechanisms which is being used to minimize the energy consumption of nodes and prolong the lifetime of the network. In this paper, therefore, we propose a robust clustering mechanism for energy optimization in heterogeneous WSNs. In the proposed scheme, nodes declare themselves as cluster head (CH) based on available resources such as residual energy, available storage and computational capability. The proposed scheme employs the multi criteria decision making technique named as Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) which allows the child nodes to select the optimal CH among several potential CH candidates. Moreover, we also propose mechanisms such as CH-acquaintanceship and CH-friendship in order to prolong the network lifetime. Simulation results show that our proposed scheme minimizes the control overhead, reduces the power consumption and enhances overall lifetime of the network by comparing with the most recent and relevant proposed protocol for WSNs.

Enhancement of Withstand Voltage in Silicon Strain Gauges Using a Thin Alkali-Free Glass.

We present a cost-effective approach to produce silicon strain gauges that can withstand very high voltage without using any complex package design and without sacrificing any sensor performance. This is achieved by a special silicon strain gauge structure created on an alkali-free glass substrate that has a high breakdown voltage. A half-bridge silicon strain gauge is designed, fabricated, and then tested to measure its output characteristics. The device has a glass layer that is only 25-55 µm thick; it shows it is able to withstand a voltage of over 2000 V while maintaining a high degree of linearity with correlation coefficients higher than 0.9990 and an average sensitivity of 104.13. Due to their unique electrical properties, silicon strain gauges-on-glass chips hold much promise for use in advanced force and pressure sensors.

A Fully Integrated Paper-Microfluidic Electrochemical Device for Simultaneous Analysis of Physiologic Blood Ions.

A fully integrated paper microfluidic electrochemical device equipped with three different cation permeable films is developed to determine blood ions (Cl-, Na⁺, K⁺, and Ca2+) at a time. These blood ions that are normally dissolved in the real human blood stream are essential for cell metabolisms and homeostasis in the human body. Abnormal concentration of blood ions causes many serious disorders. The optimized microfluidic device working without any external power source can directly and effectively separate human blood components, and subsequently detect a specific blood ion with minimized interference. The measured sensitivity to Cl-, K⁺, Na⁺, and Ca2+ are -47.71, 45.97, 51.06, and 19.46 in mV decade-1, respectively. Potentiometric responses of the microfluidic devices to blood serum samples are in the normal ranges of each cation, and comparable with responses from the commercial blood ion analyzer Abbott i-Stat.

Measurement and Estimation of Renal Size by Computed Tomography in Korean Children.

Adequate organ growth is an important aspect of growth evaluation in children. Renal size is an important indicator of adequate renal growth; computed tomography (CT) can closely estimate actual kidney size. However, insufficient data are available on normal renal size as measured by CT. This study aimed to evaluate the relationships of anthropometric indices with renal length and volume measured by CT in Korean pediatric patients. Renal length and volume were measured using CT images in 272 pediatric patients (age < 18 years) without renal disease. Data for anthropometric indices-including height, weight, and body surface area (BSA)-were obtained using medical records. Using the equation for an ellipsoid, renal volume was calculated in cubic centimeters. Height showed greatest correlation with renal length on stepwise multiple linear regression analysis; BSA showed the strongest significant correlation with renal volume. The mean renal size for each age group and height group was determined; it showed a tendency to increase with age and height. This is the first Korean study to report the relationship between body indices and renal size measured by CT. These results can serve as normative standards for assessing adequate renal growth.

Henoch-Schonlein purpura without typical lesions, presenting with gastrointestinal manifestations and kidney involvement following influenza - A case report.

We report a case of Henoch-Schonlein purpura (HSP) presenting without typical skin lesion; atypical symptoms initially appeared following influenza infection. A 4-year-old girl with influenza presented with epigastric pain and vomiting. On physical examination, there was epigastric tenderness, but no other signs, such as skin rash. On the second day, she vomited blood 10 times. Ultrasonography indicated focal bowel wall thickening in the right upper quadrant. Esophagogastroduodenoscopy showed oedematous and purpuric mucosa in the gastric pylorus and duodenum. Steroid therapy was initiated, and symptoms improved, but microscopic haematuria persisted. Even in the absence of typical purpura, if any gastrointestinal symptoms are observed and HSP is suspected, aggressive diagnostic tools must be considered, including ultrasonography or endoscopy. With only a few reported cases of HSP associated with influenza infection, this is the first reported case with gastrointestinal involvement and renal impairment, but without typical skin lesions.

A novel small-molecule PPI inhibitor targeting integrin αvß3-osteopontin interface blocks bone resorption in vitro and prevents bone loss in mice.

Small molecule-inhibition targeting protein-protein interaction (PPI) is now recognized as an emerging and challenging area in drug design. We developed a novel interactive drug discovery methodology known as Protein Chip technology (ProteoChip) as a cutting-edge PPI assay system applicable for unique PPI-targeting therapeutics integrated with computer-aided drug design (CADD). Here, we describe a novel small molecular PPI inhibitor, IPS-02001, which the blocks integrin αvß3-osteopontin interface a novel PPI inhibitor identified by the interactive methodology of both ProteoChip- and CADD-based PPI assay. IPS-02001 (6,7-Dichloro-2,3,5,8-tetrahydroxy-1,4-naphthoquinone) was screened from different compound libraries (InterBioScreen, Commercial libraries) using an in silico structure-based molecular docking simulation method and a protein chip-based protein-protein interaction assay system. Additionally, integrin αvß3, an adhesion receptor expressed in osteoclasts (OCs), was implicated in the regulation of OC function via regulation of the cytoskeletal organization of OCs. IPS-02001 blocked OC maturation from murine bone marrow-derived macrophages, as well as the resorptive function of OCs. Moreover, treatment with IPS-02001 impaired downstream signaling of integrin αvß3 linked to Pyk2, c-Src, PLCγ2, and Vav3 and disrupted the actin cytoskeleton in mature OCs. Furthermore, IPS-02001 blocked RANKL-induced bone destruction by reducing the number of OCs and protected against ovariectomy-induced bone loss in mice. Thus, IPS-02001 may represent a promising new class of anti-resorptive drugs for treatment of bone diseases associated with increased OC function.

Effects of hypoxia/ischemia on catabolic mediators of cartilage in a human chondrocyte, SW1353.

Cells from a human chondrocyte cell line were studied in 1% oxygen and/or a lower glucose concentration (5.5 mM), compared to the routine culture conditions of normoxia and high glucose. HIF-1α, IL-1ß, IL-6, IL-8, COX-2, TNFα, LIF, MMP-3, MMP-13, and reactive oxygen species (ROS) were evaluated, respectively. Effects of hypoxia inducing expression of HIF-1α were statistically significant at 72 h (p<0.05). Increased production of ROS by hypoxia was also observed with passage of time (p<0.05). The effects of hypoxia on HIF-1α and IL-1ß were potentiated by 5.5 mM glucose, especially after 48 h (p<0.05). IL-8 production was significantly induced in 1% O(2), with 5.5 mM glucose (p<0.01). IL-8 mRNA expression and production in response to IL-1ß were potentiated by hypoxia/ischemia (p<0.05, p<0.01, respectively). Up-regulation of IL-1ß, ROS, and IL-8 by hypoxia/ischemia in human chondrocytes may occur in correlation with HIF-1α. IL-8 response to IL-1ß may be potentiated synergically by hypoxia/ischemia, as an effector of hypoxia/ischemia. The results may suggest aggressive biology of the ordinary cartilage hypoxia/ischemia in the context of arthro-degeneration.

A fully microfabricated carbon nanotube three-electrode system on glass substrate for miniaturized electrochemical biosensors.

We present an integration process to fabricate single-walled carbon nanotube (SWCNT) three-electrode systems on glass substrate for electrochemical biosensors. Key issues involve optimization of the SWCNT working electrode to achieve high sensitivity, developing an optimal Ag/AgCl reference electrode with good stability, and process development to integrate these electrodes. Multiple spray coatings of the SWCNT film on glass substrate enabled easier integration of the SWCNT film into an electrochemical three-electrode system. O2 plasma etching and subsequent activation of spray-coated SWCNT films were needed to pattern and functionalize the SWCNT working electrode films without serious damage to the SWCNTs, and to remove organic residues. The microfabricated three-electrode systems were characterized by microscopic and spectroscopic techniques, and the electrochemical properties were investigated using cyclic voltammetry and chrono-amperometry. The fully-integrated CNT three-electrode system showed an effective working electrode area about three times larger than its geometric surface area and an improved electrochemical activity for hydrogen peroxide decomposition. Finally, the effectiveness of miniaturized pf-SWCNT electrodes as biointerfaces was examined by applying them to immunosensors to detect Legionella(L) pneumophila, based on a direct sandwich enzyme-linked immunosorbent assay (ELISA) format with 3,3',5,5'-tetramethylbenzidine dihydrochloride/hydrogen peroxide(TMB/H2O2) as the substrate/mediator system. The lower detection limit of the pf-SWCNT-based immunosensors to L. pneumophila is about 1500 times lower than that of the standard ELISA assay.

Microfabrication and characterization of spray-coated single-wall carbon nanotube film strain gauges.

We present the design, fabrication, and characterization results of single-wall carbon nanotube (SWCNT) film strain gauges for potential applications as highly sensitive strain, weight, or pressure sensors on the macro-scale. A batch microfabrication process was developed for practical device construction and packaging using spray-coated SWCNTs and a conventional semiconductor process. The prototype was characterized using a commercial metal foil gauge with tensile and compressive testing on a binocular load cell. Our test results demonstrated that the proposed SWCNT film gauges have a linear relationship between resistance changes and externally applied strain. The gauge factor ranged from 7.0 to 16.4 for four different micro-grid configurations, indicating that the maximum strain sensitivity of the prototype was approximately eight times greater than that of commercial gauges.

Electrochemical properties of a fully integrated, singlewalled carbon nanotube coplanar three-electrode system on glass substrate.

Fully integrated carbon nanotube-based three-electrode electrochemical systems were photolithographically prepared on glass substrates and electrochemically characterized. O(2) plasma treatment of the transferred single-walled carbon nanotube (SWCNT) film was voltammetrically optimized in terms of applied plasma power and the elapsed time. The patterned thin film Ag layer was chemically oxidized in an acidic solution for various dip times to form a chlorinated Ag layer. The Nernstian behavior of as-prepared and seven-day-aged Ag/AgCl thin-film electrodes was investigated for optimization, and the electrode's electrochemical attributes were compared to a commercial reference electrode. A quality control evaluation and a performance assessment of the fully integrated SWCNT-transferred sensing systems were performed using cyclic voltammetry. The proposed SWCNT-based three-electrode device exhibited clear electrochemistry under voltammetric conditions, and is therefore a candidate for use in all electrochemical biosensors.

Erkitinib, a novel EGFR tyrosine kinase inhibitor screened using a ProteoChip system from a phytochemical library.

Receptor tyrosine kinases (PTKs) play key roles in the pathogenesis of numerous human diseases, including cancer. Therefore PTK inhibitors are currently under intensive investigation as potential drug candidates. Herein, we report on a ProteoChip-based screening of an epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitor, Erkitinibs, from phytochemical libraries. PLC-gamma-1 was used as a substrate immobilized on a ProteoChip and incubated with an EGFR kinase to phosphorylate tyrosine residues of the substrate, followed by a fluorescence detection of the substrate recognized by a phospho-specific monoclonal antibody. Erkitinibs inhibited HeLa cell proliferation in a dose-dependent manner. In conclusion, these data suggest that Erkitinibs can be a specific inhibitor of an EGFR kinase and can be further developed as a potent anti-tumor agent.

Knoellia aerolata sp. nov., isolated from an air sample in Korea.

An aerobic, Gram-positive, non-motile, non-spore-forming, rod-coccus-shaped bacterium, strain 5317S-21(T), was isolated from an air sample from Suwon city, Republic of Korea. The isolate was able to grow within a pH range of 5.0-9.0 and a temperature range of 5-35 degrees C and it tolerated up to 2 % (w/v) NaCl. The cell-wall peptidoglycan contained meso-diaminopimelic acid as diagnostic diamino acid. The predominant isoprenoid quinone was MK-8(H(4)). The major polar lipids were phosphatidylinositol, phosphatidylethanolamine and diphosphatidylglycerol; phosphatidylglycerol and several unknown phospholipids were also detected. Mycolic acids were absent. The only whole-cell sugar was glucose. The major cellular fatty acids were iso-C(16 : 0), C(17 : 1)omega8c and iso-C(15 : 0). 16S rRNA gene sequence analysis indicated that strain 5317S-21(T) was related phylogenetically to members of the genus Knoellia, with 97.4 % sequence similarity to the type strains of Knoellia sinensis and Knoellia subterranea. The G+C content of the genomic DNA of strain 5317S-21(T) was 73 mol%. Levels of DNA-DNA relatedness between strain 5317S-21(T) and the type strains of Knoellia sinensis and Knoellia subterranea were 37 and 41 %, respectively. It was concluded that strain 5317S-21(T) represents a novel species of the genus Knoellia, for which the name Knoellia aerolata sp. nov. is proposed. The type strain is 5317S-21(T) (=KACC 20583(T) =DSM 18566(T)).

Endoscopic bilateral metal stent placement for advanced hilar cholangiocarcinoma: a pilot study of a newly designed Y stent.

BACKGROUND: Although endoscopic stent placement is now generally accepted as a palliative method of treatment in unresectable hilar cholangiocarcinoma, exclusively endoscopic placement of bilateral metal stents has been considered very difficult and complex. OBJECTIVE: To evaluate the technical and clinical efficacy of endoscopic placement of dual, newly designed stents in a Y configuration. DESIGN: Prospective, uncontrolled, single center. SETTING: Tertiary referral university hospital. PATIENTS: Ten patients with unresectable hilar cholangiocarcinoma of Bismuth type II or higher. INTERVENTIONS: For bilateral metal stent placement, a biliary Y stent with central wide-open mesh was used exclusively at first. A second stent was placed into the contralateral hepatic duct through the central open mesh of the Y stent. MAIN OUTCOME MEASUREMENT: Technical success, functional success, early complications, and short-term clinical outcome. RESULTS: Technical success was achieved in 8 of 10 patients (80%). Among 8 patients in whom bilateral stents were successfully placed by endoscopy, functional success was 100%, the early complication rate was 0%, and the stent occlusion rate was 25%. The median stent patency period was 217 days. LIMITATIONS: Small number of patients, uncontrolled study, short-term follow-up period. CONCLUSIONS: We described a technique for endoscopic bilateral metal stent placement by using the newly designed Y stent for advanced hilar cholangiocarcinoma that resulted in a high success rate of 80%.

[Effectiveness and complications of combination therapy with interferon alpha and ribavirin in patients with chronic hepatitis C].

BACKGROUND/AIMS: The effectiveness of combination therapy with conventional or pegylated interferon alpha and ribavirin in patients with chronic hepatitis C is well understood. However, the profound investigation about complications of the treatment has been rarely reported in Korea, where patients have broader spectrum of disease manifestations. The aim of this study was to evaluate the effectiveness and complications of the combination therapy of interferon alpha and ribavirin in patients with chronic hepatitis C. METHODS: Two hundred and forty patients with chronic hepatitis C were included. All patients were treated with interferon alpha (3 million units thrice a week) in combination with ribavirin (800-1,200 mg, depending on body weight). Patients were treated for 6 or 12 months according to the genotypes (genotype 1; 12 months, non-1; 6 months). We retrospectively evaluated ETR (end of treatment response) and SVR (sustained virologic response) on the basis of intent-to-treat in patients completing the therapy. RESULTS: In 154 patients who had completed the therapy, ETR was 79.2% and SVR was 61.0%. Multivariate analysis showed that genotype and early virologic response at 3 months of treatment were independent predictive factors of SVR. Due to insufficient response, 11.3% of the patients discontinued the therapy. In addition, 24.5% of the patients prematurely discontinued the therapy due to adverse events including aggravated liver function (15.4%), failure to return (7.9%), and others (1.2%). Dose modifications of interferon alpha or ribavirin were required due to anemia (15.4%), neutropenia (8.8%), or thrombocytopenia (4.6%). CONCLUSIONS: The overall SVR of patients who had completed the combination therapy with interferon alpha and ribavirin was 61.0%. However, about one third of the patients discontinued the therapy prematurely due to insufficient response, adverse events and/or noncompliance.

Endoscopic grading of atrophic gastritis is inversely associated with gastroesophageal reflux and gastropharyngeal reflux.

BACKGROUND: Reflux esophagitis is inversely associated with the presence of atrophic gastritis, and endoscopic grading of atrophic gastritis correlates with histological evaluation. The aim of this study was to investigate the association of the endoscopic grade of atrophic gastritis with gastroesophageal and gastropharyngeal reflux. METHODS: A total of 627 patients, who underwent endoscopy and ambulatory 24-hour dual-probe pH monitoring, were included in this study. The grade of atrophic gastritis was endoscopically classified into 2 types with the atrophic pattern system: the closed-type (C-type) and the open-type (O-type). We compared the findings from endoscopy and ambulatory pH monitoring for these 2 types. RESULTS: The O-type was significantly associated with a lower prevalence of reflux esophagitis (p = 0.001). All variables showing gastroesophageal reflux in the distal probe were significantly lower in the O-type than in the C-type (p < 0.05). Similarly for the proximal probe, all variables, except the supine time of pH < 4, were significantly lower in the O-type than in the C-type (p < 0.05). The frequency of gastroesophageal reflux disease and gastropharyngeal reflux disease was in significantly lower in the O-type than in the C-type (p < 0.001, p = 0.012, respectively). CONCLUSIONS: Endoscopic grading of atrophic gastritis is easy and is inversely associated with gastroesophageal and gastropharyngeal reflux.