A Distributed Public Key Caching Scheme in Large Wireless Networks.

When asymmetric cryptography techniques are used in wireless networks, the public keys of the nodes need to be widely available and signed by a Certificate Authority (CA). However, the existence of a single CA in large wireless networks such as mobile ad hoc networks and wireless sensor networks can lead the hotspot problem and become a security weakness. In this work, we propose a distributed technique to cache the public keys on regular nodes. Due to the limited memory size that each node is allowed to dedicate for key caching, only some keys can be cached. In our proposed technique, each node caches the public keys of a mix of local and remote nodes. The local nodes are defined as the nodes within the same neighborhood according to the transmission range, while the remote nodes are the ones outside the range. Access to the public keys of other nodes is possible based on a chain of trust. Multiple copies of public keys from different chains of trusted nodes provide fault tolerance. We explain our technique in detail and investigate its salient features in this work. An interesting observation is the need to balance caching public keys of local nodes and remote nodes. We studied the optimum local/remote public key caching ratios for different networks via investigating the availability of the number of required public key copies. These simulation results showed that by balancing the caching public keys with the optimum ratios, the availability of the required public keys kept increasing and finally became stable. We also did the simulation about studying the number of hops to find the first copies of required public keys. The results showed how local/remote ratios affected the minimum number of hops for reaching the first copies

An experimental and theoretical study of cobalt (II) and nickel (II) complexes with acetonitrile as ligands

Acetonitrile is a weak base and is not frequently used as a ligand in coordination chemistry investigations. Due to the nature of this ligand, it was thought that cobalt(II) and nickel(II) complexes with acetonitrile ligands would be unstable and that the solid state of these complexes probably would not exist. Basolo1 indicated that solid salts separated from solution easiest for combinations of either small-small or large-large cations and anions, preferably with systems having the same but opposite charges on the counter ions. The driving force for the large cation-large anion combination to form solid is the small hydration energy of the ions. When Co (II) and Ni(II) are completely solvated by acetonitrile, they form large cations; these large cations could be effectively stabilized by large anions such as tetrachlorometallates or tetrabromometallates. The purpose of this study is fourfold. The first is to synthesize the complexes by using large anions, BCl4 and BBr4. The second is to compare results with similar systems. The third is to make theoretical investigations of the molecular model assuming distortion and the last is to analyze the complexes experimentally

The Counseling Training Environment Scale (CTES) : development of a self-report measure to assess counseling training environment

Based on Bronfenbrenner's (1979, 1992) ecological framework, the Counseling Training Environment Scale (CTES) was developed as a self-report measure that assesses the learning and training environment of counseling and related mental health training programs as perceived by current students. A two-phase mixed-methods design was used to create and psychometrically evaluate the CTES: (a) item development, and (b) assessment of the outcomes to examine for preliminary evidence of validity and reliability. The results of the item development and content validation process yielded 128 items, of which 34 were used for the final intact version of the CTES. A confirmatory factor analysis (CFA) was conducted on four models of the CTES: (a) 34-item single-factor model, (b) 34-item five-factor model, (c) 26-item modified five-factor model, and (d) 24-item modified single-factor model. Results of the CFA suggest that despite not conforming to the hypothesized model of Bronfenbrenner's (1979, 1992) ecological theory, the data gathered from the modified 24-item single-factor CTES demonstrated the best fit on the following fit indices: NNFI (.95), CFI (.96), SRMR (.04), and RMSEA (.04). The modified 24-item CTES was also found to demonstrate strong reliability and temporal stability as demonstrated through Classical Test Theory analyses (a = .92) and test-retest reliability (r = .90, p< .01, two-tailed)

The prevalence of simulation technology in athletic training clinical education

Athletic training clinical education is the most integral component in the transition into practice. However, barriers within clinical education exist, which may affect athletic training students' professional preparedness. Simulation technology, within other healthcare professionals' education, has shown promising benefits. However, research regarding simulation technology in athletic training is limited, with current practices relatively unknown. This study assessed the prevalence of simulation technology and explored factors that influence its use in athletic training clinical education. Athletic training program directors or clinical coordinators (n=54) completed an online survey via Qualtrics. The survey examined current simulation technology practices in clinical education. Additionally, participants rated the influence of barriers, challenges, and facilitators on its use. Survey responses indicated that 31 of 54 programs were using some form of simulation technology, with an additional 11 programs stating they were considering using it in the future. Within these programs, high-fidelity simulation (n=22) was the predominant type used. In addition, most of these programs noted improvements in professional competencies (e.g., decision-making, skill development) and clinical experiences (i.e., engaged time, incident variety), 84% and 77%, respectively. Of the 54 programs, 36 rated "high financial cost" as a very influential barrier. "Limited staffing and availability" were also found to be big challenges. On the other hand, 26 of 54 programs rated "additional healthcare programs" very influential, the most among facilitators. The results indicate that simulation technology is currently used within athletic training clinical education, but barriers still influence its use. Future research should continue examining simulation technology's benefits and exploring specific implementation strategies to improve use

Surface-enhanced Raman spectroscopy study of 4-ATP on gold nanoparticles for basal cell carcinoma fingerprint detection

The surface-enhanced Raman signals of 4-aminothiophenol (4-ATP) attached to the surface of colloidal gold nanoparticles with size distribution of 2 to 5 nm were used as a labeling agent to detect basal cell carcinoma (BCC) of the skin. The enhanced Raman band at 1075 cm-1 corresponding to the C-S stretching vibration in 4-ATP was observed during attachment to the surface of the gold nanoparticles. The frequency and intensity of this band did not change when the colloids were conjugated with BerEP4 antibody, which specifically binds to BCC. We show the feasibility of imaging BCC by surface-enhanced Raman spectroscopy, scanning the 1075 cm-1 band to detect the distribution of 4ATP-coated gold nanoparticles attached to skin tissue ex vivo

Modelling generalized firms' restructuring using inverse DEA

The key consideration for firms’ restructuring is improving their operational efficiencies. Market conditions often offer opportunities or generate threats that can be handled by restructuring scenarios through consolidation, to create synergy, or through split, to create reverse synergy. A generalized restructuring refers to a move in a business market where a homogeneous set of firms, a set of pre-restructuring decision making units (DMUs), proceed with a restructuring to produce a new set of post-restructuring entities in the same market to realize efficiency targets. This paper aims to develop a novel inverse Data Envelopment Analysis based methodology, called GInvDEA (Generalized Inverse DEA), for modeling the generalized restructuring. Moreover, the paper suggests a linear programming model that allows determining the lowest performance levels, measured by efficiency that can be achieved through a given generalized restructuring. An application in banking operations illustrates the theory developed in the paper

Reduced Gray to White Matter Tissue Intensity Contrast in Schizophrenia

BACKGROUND: While numerous structural magnetic resonance imaging (MRI) studies revealed changes of brain volume or density, cortical thickness and fibre integrity in schizophrenia, the effect of tissue alterations on the contrast properties of neural structures has so far remained mostly unexplored. METHODS: Whole brain high-resolution MRI at 3 Tesla was used to investigate tissue contrast and cortical thickness in patients with schizophrenia and healthy controls. RESULTS: Patients showed significantly decreased gray to white matter contrast in large portions throughout the cortical mantle with preponderance in inferior, middle, superior and medial temporal areas as well as in lateral and medial frontal regions. The extent of these intensity contrast changes exceeded the extent of cortical thinning. Further, contrast changes remained significant after controlling for cortical thickness measurements. CONCLUSIONS: Our findings clearly emphasize the presence of schizophrenia related brain tissue changes that alter the imaging properties of brain structures. Intensity contrast measurements might not only serve as a highly sensitive metric but also as a potential indicator of a distinct pathological process that might be independent from volume or thickness alterations

FOXA1 repression is associated with loss of BRCA1 and increased promoter methylation and chromatin silencing in breast cancer

FOXA1 expression correlates with the breast cancer luminal subtype and patient survival. RNA and protein analysis of a panel of breast cancer cell lines revealed that BRCA1 deficiency is associated with the downregulation of FOXA1 expression. Knockdown of BRCA1 resulted in the downregulation of FOXA1 expression and enhancement of FOXA1 promoter methylation in MCF-7 breast cancer cells, whereas the reconstitution of BRCA1 in Brca1-deficent mouse mammary epithelial cells (MMECs) promoted Foxa1 expression and methylation. These data suggest that BRCA1 suppresses FOXA1 hypermethylation and silencing. Consistently, the treatment of MMECs with the DNA methylation inhibitor 5-aza-2'-deoxycitydine induced Foxa1 mRNA expression. Furthermore, treatment with GSK126, an inhibitor of EZH2 methyltransferase activity, induced FOXA1 expression in BRCA1-deficient but not in BRCA1-reconstituted MMECs. Likewise, the depletion of EZH2 by small interfering RNA enhanced FOXA1 mRNA expression. Chromatin immunoprecipitation (ChIP) analysis demonstrated that BRCA1, EZH2, DNA methyltransferases (DNMT)1/3a/3b and H3K27me3 are recruited to the endogenous FOXA1 promoter, further supporting the hypothesis that these proteins interact to modulate FOXA1 methylation and repression. Further co-immunoprecipitation and ChIP analysis showed that both BRCA1 and DNMT3b form complexes with EZH2 but not with each other, consistent with the notion that BRCA1 binds to EZH2 and negatively regulates its methyltransferase activity. We also found that EZH2 promotes and BRCA1 impairs the deposit of the gene silencing histone mark H3K27me3 on the FOXA1 promoter. These associations were validated in a familial breast cancer patient cohort. Integrated analysis of the global gene methylation and expression profiles of a set of 33 familial breast tumours revealed that FOXA1 promoter methylation is inversely correlated with the transcriptional expression of FOXA1 and that BRCA1 mutation breast cancer is significantly associated with FOXA1 methylation and downregulation of FOXA1 expression, providing physiological evidence to our findings that FOXA1 expression is regulated by methylation and chromatin silencing and that BRCA1 maintains FOXA1 expression through suppressing FOXA1 gene methylation in breast cancer.Oncogene advance online publication, 22 December 2014; doi:10.1038/onc.2014.421.published_or_final_versio

Early metabolic response using FDG PET/CT and molecular phenotypes of breast cancer treated with neoadjuvant chemotherapy

Background: This study was aimed 1) to investigate the predictive value of FDG PET/CT (fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography) for histopathologic response and 2) to explore the results of FDG PET/CT by molecular phenotypes of breast cancer patients who received neoadjuvant chemotherapy. Methods: Seventy-eight stage II or III breast cancer patients who received neoadjuvant docetaxel/doxorubicin chemotherapy were enrolled in this study. FDG PET/CTs were acquired before chemotherapy and after the first cycle of chemotherapy for evaluating early metabolic response. Results: The mean pre- and post-chemotherapy standard uptake value (SUV) were 7.5 and 3.9, respectively. The early metabolic response provided by FDG PET/CT after one cycle of neoadjuvant chemotherapy was correlated with the histopathologic response after completion of neoadjuvant chemotherapy (P = 0.002). Sensitivity and negative predictive value were 85.7% and 95.1%, respectively. The estrogen receptor negative phenotype had a higher pre-chemotherapy SUV (8.6 vs. 6.4, P = 0.047) and percent change in SUV (48% vs. 30%, P = 0.038). In triple negative breast cancer (TNBC), the pre-chemotherapy SUV was higher than in non-TNBC (9.8 vs. 6.4, P = 0.008). Conclusions: The early metabolic response using FDG PET/CT could have a predictive value for the assessment of histopathologic non-response of stage II/III breast cancer treated with neoadjuvant chemotherapy. Our findings suggest that the initial SUV and the decline in SUV differed based on the molecular phenotype

Assessment of MMP-9, TIMP-1, and COX-2 in normal tissue and in advanced symptomatic and asymptomatic carotid plaques

<p>Abstract</p> <p>Background</p> <p>Mature carotid plaques are complex structures, and their histological classification is challenging. The carotid plaques of asymptomatic and symptomatic patients could exhibit identical histological components.</p> <p>Objectives</p> <p>To investigate whether matrix metalloproteinase 9 (MMP-9), tissue inhibitor of MMP (TIMP), and cyclooxygenase-2 (COX-2) have different expression levels in advanced symptomatic carotid plaques, asymptomatic carotid plaques, and normal tissue.</p> <p>Methods</p> <p>Thirty patients admitted for carotid endarterectomy were selected. Each patient was assigned preoperatively to one of two groups: group I consisted of symptomatic patients (n = 16, 12 males, mean age 66.7 ± 6.8 years), and group II consisted of asymptomatic patients (n = 14, 8 males, mean age 67.6 ± 6.81 years). Nine normal carotid arteries were used as control. Tissue specimens were analyzed for fibromuscular, lipid and calcium contents. The expressions of MMP-9, TIMP-1 and COX-2 in each plaque were quantified.</p> <p>Results</p> <p>Fifty-eight percent of all carotid plaques were classified as Type VI according to the American Heart Association Committee on Vascular Lesions. The control carotid arteries all were classified as Type III. The median percentage of fibromuscular tissue was significantly greater in group II compared to group I (<it>p </it>< 0.05). The median percentage of lipid tissue had a tendency to be greater in group I than in group II (<it>p </it>= 0.057). The percentages of calcification were similar among the two groups. MMP-9 protein expression levels were significantly higher in group II and in the control group when compared with group I (p < 0.001). TIMP-1 expression levels were significantly higher in the control group and in group II when compared to group I, with statistical difference between control group and group I (p = 0.010). COX-2 expression levels did not differ among groups. There was no statistical correlation between MMP-9, COX-2, and TIMP-1 levels and fibrous tissue.</p> <p>Conclusions</p> <p>MMP-9 and TIMP-1 are present in all stages of atherosclerotic plaque progression, from normal tissue to advanced lesions. When sections of a plaque are analyzed without preselection, MMP-9 concentration is higher in normal tissues and asymptomatic surgical specimens than in symptomatic specimens, and TIMP-1 concentration is higher in normal tissue than in symptomatic specimens.</p