An Elliptic Curve-based Signcryption Scheme with Forward Secrecy

An elliptic curve-based signcryption scheme is introduced in this paper that effectively combines the functionalities of digital signature and encryption, and decreases the computational costs and communication overheads in comparison with the traditional signature-then-encryption schemes. It simultaneously provides the attributes of message confidentiality, authentication, integrity, unforgeability, non-repudiation, public verifiability, and forward secrecy of message confidentiality. Since it is based on elliptic curves and can use any fast and secure symmetric algorithm for encrypting messages, it has great advantages to be used for security establishments in store-and-forward applications and when dealing with resource-constrained devices.Comment: 13 Pages, 5 Figures, 2 Table

Solutions to the GSM Security Weaknesses

Recently, the mobile industry has experienced an extreme increment in number of its users. The GSM network with the greatest worldwide number of users succumbs to several security vulnerabilities. Although some of its security problems are addressed in its upper generations, there are still many operators using 2G systems. This paper briefly presents the most important security flaws of the GSM network and its transport channels. It also provides some practical solutions to improve the security of currently available 2G systems.Comment: 6 Pages, 2 Figure

God Loveth Adverbs: Teaching (and Living) Christianly

In my current role as a teacher educator, I strive to help my students (pre-service teachers) understand what it means to \u27teach Christianly.\u27 If I’m honest about it, I am still striving to fully understand what this means in my own teaching practice. Posting about being a Christ-like teacher from In All Things - an online hub committed to the claim that the life, death, and resurrection of Jesus Christ has implications for the entire world. http://inallthings.org/god-loveth-adverbs-teaching-and-living-christianly

Determination of relationship between wheat farm size and energy indexes in west Azerbaijan province, Iran

The objective of this study was to determine the relationship between farm size and energy productivity of wheat production in west Azerbaijan province, Iran.  Farmers with different farm sizes (less than two hectares, between two and five hectares and more than five hectares) were randomly selected.  Questionnaires were filled by 61 farmers.  Then total used energy, produced energy, energy productivity and energy ratio were calculated for each farm.  Also the relationship between energy indexes and three methods of tillage and planting (combination machine, seed drill and seed spreader) and three harvesting methods (combine harvester, mower and hand tools) were calculated.  The data were analyzed by SPSS software.  The results showed that fertilizers (43%) and machinery (40%) was the maximum portion of total used energy on farm.  There was no significant linear relationship between the farm size and energy indexes.  There was no significant relationship between energy indexes and harvesting methods.  But there was a significant relationship between tillage and planting methods and energy indexes.  Results showed that tillage and planting methods such as combination tillage and planter machine application increases the effect of farm size on energy indexes.   Keywords: farm size, energy productivity, used energy, energy production

Effects of Chewing Different Flavored Gums on Salivary Flow Rate and pH

Chewing gum increases salivary flow rate (SFR) and pH, but differences in preferences of gum flavor may influence SFR and pH. The aim of this paper was to assess the effect of five different flavors of sucrose-free chewing gum on the salivary flow rate and pH in healthy dental students in Isfahan, Iran. Fifteen (7 men and 8 women) healthy dental student volunteers collected unstimulated saliva and then chewed one of five flavored gums for 6 min. The whole saliva was collected and assessed for 6 consecutive days. After unstimulated saliva was collected, stimulated saliva was collected at interval of 0-1, 1–3, and 3–6 minutes after the start of different flavored chewing gums. The SFR and salivary pH were measured. The SFR increased in all five flavored gums at 1, 3, and 6 minutes after start of chewing gums (P < 0.001). The flow rate of all products reached peak in the 1st minute of stimulation, except spearmint-flavored gums which reached peak in the 6th minute. In the 1st minute, the strawberry-flavored gums showed the highest SFR. During 1–3 minutes, strawberry- and apple-flavored gums showed higher SFR, respectively. Only the spearmint- and cinnamon-flavored gum significantly increased salivary pH. Gum flavored can affect the SFR and pH and special flavors can be advised for different individuals according to their oral conditions

Mitral Valve Surgery in Patients with Systemic Lupus Erythematosus

Valvular heart disease is the common cardiac manifestation of systemic lupus erythematosus (SLE) with a tendency for mitral valve regurgitation. In this study we report a case of mitral valve replacement for mitral stenosis caused by Libman-Sacks endocarditis in the setting of SLE. In addition, we provide a systematic review of the literature on mitral valve surgery in the presence of Libman-Sacks endocarditis because its challenge on surgical options continues. Surgical decision depends on structural involvement of mitral valve and presence of active lupus nephritis and antiphospholipid antibody syndrome. Review of the literature has also shown that outcome is good in most SLE patients who have undergone valvular surgery, but association of antiphospholipid antibody syndrome with SLE has negative impact on the outcome

Entrepreneurial orientation and innovation performance: the mediating role of knowledge management.

Abstract: Firms with greater innovativeness will be more successful in responding to changing environments and in developing new capabilities that allow them to achieve better performance. Former researchers have emphasized that Entrepreneurial Orientation (EO) is a key ingredient for firm innovation. This study tried to accentuate the role of Knowledge Management (KM) in the relations of Entrepreneurial Orientation (EO) and innovation performance. The population in the study was 164 Iranian SMEs. This study developed and simultaneously tested three hypotheses about: (1) The impact of EO on innovation performance, (2) The impact of EO on KM, and (3) The impact of km on innovation performance. LISREL software was used to test the hypotheses. The results indicated that entrepreneurial orientation both directly (B = 0.38) and indirectly through the knowledge management (B = 0.377) affected innovation performance. Hence, knowledge management acts as a mediator between entrepreneurial orientation and innovation performance

Value of Ga-68-labeled bombesin antagonist (RM2) in the detection of primary prostate cancer comparing with [F-18]fluoromethylcholine PET-CT and multiparametric MRI-a phase I/II study

Objectives The bombesin derivative RM2 is a GRPr antagonist with strong binding affinity to prostate cancer (PCa). In this study, the impact of [Ga-68]Ga-RM2 positron emission tomography-computed tomography (PET-CT) for the detection of primary PCa was compared with that of [F-18]FCH PET-CT and multiparametric magnetic resonance imaging (mpMRI).Methods This phase I/II study was conducted in 30 biopsy-positive PCa subjects. The patients were stratified into high (10 patients), intermediate (10 patients), and low risk (10 patients) for extraglandular metastases as defined by National Comprehensive Cancer Network (NCCN) criteria (NCCN Clinical Practice Guidelines in Oncology, 2016). The prostate gland was classified in 12 anatomic segments for data analysis of the imaging modalities as well as histopathologic findings. The segment with the highest radiotracer uptake was defined as the "index lesion." All cases were scheduled to undergo prostatectomy with pelvic lymph node (LN) dissection in intermediate- and high-risk patients. Intraprostatic and pelvic nodal [Ga-68]Ga-RM2 and [F-18]FCH PET-CT findings were correlated with mpMRI and histopathologic results.Results Of the 312 analyzed regions, 120 regions (4 to 8 lesions per patient) showed abnormal findings in the prostate gland. In a region-based analysis, overall sensitivity and specificity of [Ga-68]Ga-RM2 PET-CT in the detection of primary tumor were 74% and 90%, respectively, while it was 60% and 80% for [F-18]FCH PET-CT and 72% and 89% for mpMRI. Although the overall sensitivity of [Ga-68]Ga-RM2 PET-CT was higher compared to that of [F-18]FCH PET-CT and mpMRI, the statistical analysis showed only significant difference between [Ga-68]Ga-RM2 PET-CT and [F-18]FCH PET-CT in the intermediate-risk group (p = 0.01) and [Ga-68]Ga-RM2 PET-CT and mpMRT in the high-risk group (p = 0.03). In the lesion-based analysis, there was no significant difference between SUVmax of [Ga-68]Ga-RM2 and [F-18]FCH PET-CT in the intraprostatic malignant lesions ([Ga-68]Ga-RM2: mean SUVmax: 5.98 +/- 4.13, median: 4.75; [F-18]FCH: mean SUVmax: 6.08 +/- 2.74, median: 5.5; p = 0.13).Conclusions [Ga-68]Ga-RM2 showed promising PET tracer for the detection of intraprostatic PCa in a cohort of patients with different risk stratifications. However, significant differences were only found between [Ga-68]Ga-RM2 PET-CT and [F-18]FCH PET-CT in the intermediate-risk group and [Ga-68]Ga-RM2 PET-CT and mpMRT in the high-risk group. In addition, GRP-R-based imaging seems to play a complementary role to choline-based imaging for full characterization of PCa extent and biopsy guidance in low- and intermediate-metastatic-risk PCa patients and has the potential to discriminate them from those at higher risks.</p

Respiratory Motion Detection and Correction in ECG-Gated SPECT: a New Approach

Objective: Gated myocardial perfusion single-photon emission computed tomography (GSPECT) has been established as an accurate and reproducible diagnostic and prognostic technique for the assessment of myocardial perfusion and function. Respiratory motion is among the major factors that may affect the quality of myocardial perfusion imaging (MPI) and consequently the accuracy of the examination. In this study, we have proposed a new approach for the tracking of respiratory motion and the correction of unwanted respiratory motion by the use of respiratory-cardiac gated-SPECT (RC-GSPECT). In addition, we have evaluated the use of RC-GSPECT for quantitative and visual assessment of myocardial perfusion and function. Materials and Methods: Twenty-six patients with known or suspected coronary artery disease (CAD)-underwent two-day stress and rest 99mTc-Tetrofosmin myocardial scintigraphy using both conventional GSPECT and RC-GSPECT methods. The respiratory signals were induced by use of a CT real-time position management (RPM) respiratory gating interface. A PIO-D144 card, which is transistor-transistor logic (TTL) compatible, was used as the input interface for simultaneous detection of both ECG and respiration signals. Results: A total of 26 patients with known or suspected CAD were examined in this study. Stress and rest myocardial respiratory motion in the vertical direction was 8.8-16.6 mm (mean, 12.4 ± 2.9 mm) and 7.8-11.8 mm (mean, 9.5 ± 1.6 mm), respectively. The percentages of tracer intensity in the inferior, inferoseptal and septal walls as well as the inferior to lateral (I/L) uptake ratio was significantly higher with the use of RC-GSPECT as compared to the use of GSPECT (p &lt; 0.01). In a left ventricular ejection fraction (LVEF) correlation analysis between the use of rest GSPECT and RC-GSPECT with echocardiography, better correlation was noted between RC-GSPECT and echocardiography as compared with the use of GSPECT (y = 0.9654x + 1.6514; r = 0.93, p &lt; 0.001 versus y = 0.8046x + 5.1704; r = 0.89, p &lt; 0.001). Nineteen (19/26) patients (73.1) showed abnormal myocardial perfusion scans with reversible regional myocardial defects; of the 19 patients, 14 (14/26) patients underwent coronary angiography. Conclusion: Respiratory induced motion can be successfully corrected simultaneously with the use of ECG-gated SPECT in MPI studies using this proposed technique. Moreover, the use of ECG-gated SPECT improved image quality, especially in the inferior and septal regions that are mostly affected by diaphragmatic attenuation. However, the effect of respiratory correction depends mainly on the patient respiratory pattern and may be clinically relevant in certain cases