The past few years have witnessed increased interest among researchers in cluster-based protocols for homogeneous networks because of their better scalability and higher energy efficiency than other routing protocols. Given the limited capabilities of sensor nodes in terms of energy resources, processing and communication range, the cluster-based protocols should be compatible with these constraints in either the setup state or steady data transmission state. With focus on these constraints, we classify routing protocols according to their objectives and methods towards addressing the shortcomings of clustering process on each stage of cluster head selection, cluster formation, data aggregation and data communication. We summarize the techniques and methods used in these categories, while the weakness and strength of each protocol is pointed out in details. Furthermore, taxonomy of the protocols in each phase is given to provide a deeper understanding of current clustering approaches. Ultimately based on the existing research, a summary of the issues and solutions of the attributes and characteristics of clustering approaches and some open research areas in cluster-based routing protocols that can be further pursued are provided.

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Located on chromosome 2q37.3, the programmed death 1 (PD1) gene encodes for PD-1 (also known as CD279), a negative co-stimulator in the immune system. PD-1 renders potent inhibitory effects on T and B lymphocytes as well as monocyte responses. Expression of PD-1 ligands by tumor cells has been reported to contribute in immune system evasion. We aimed, in current study, to investigate the association of two single nucleotide polymorphisms in PD1 gene, +7146 G to A (PD-1.3) and +7785 C to T (PD-1.5 or +872), with susceptibility and/or progression of breast carcinoma. Four hundred forty-three women with breast cancer and 328 age-sex match healthy donors were recruited in present study. Genotyping was performed using Nested polymerase chain reaction-restriction fragment length polymorphisms. Arlequin software package was used to check for the Hardy-Weinberg equilibration and to determine the haplotypes. Results revealed no significant differences in the frequencies of genotypes and alleles at PD-1.3 (P=0.252 and 0.279 for genotypes and alleles, respectively) and PD-1.5 positions (P=0.522 and 0.278 for genotypes and alleles, respectively). Four haplotypes were observed among populations with no differences in the frequency between patients and controls. Our results also revealed no association between PD1 genotypes and tumor stage, tumor size, tumor grade, lymph node involvement, vascular invasion, distant metastasis, and Nottingham prognostic index. Present data do not confirm association of PD-1.3 (+7146) G/A and PD-1.5 (+7785 or +872) C/T genetic markers with susceptibility of Iranians to breast cancer.

Background:Due to the fundamental role of gripping in most upper limb activities, grip strength promotion is a chief goal in the treatment of patients with upper limb musculoskeletal disorders. Kinesio taping is a novel and effective therapeutic technique believed to facilitate muscle contraction through stimulating mechanoreceptors and increasing the sensory feedback around the taped region.Objectives:The present study aimed to identify the best region (flexor, extensor and flexor/extensor regions) and time (immediate, 0.5, 1, 1.5, and 2 hours) of forearm Kinesio taping to obtain the maximum improvement in grip strength.Materials and Methods:In this longitudinal study, 40 healthy men and women (the mean age of 22.3 ± 2.19 years) were selected among students of Shahid Beheshti University of Medical Sciences, Tehran, Iran by simple, nonrandom sampling method. A dynamometer was used to measure grip strength immediately and every 30 minutes during the two hours after I-shaped application of tape (with 50% stretch) to the flexor, extensor, and flexor/extensor forearm muscles.Results:Grip strength was significantly increased in various muscle groups for males (P = 0.002) and females (P = 0.000) of the forearm and at different intervals for males (P = 0.000) and females (P = 0.000). Moreover, in both men and women, tape application to the extensor region provided greater grip strength compared to taping of the flexor and flexor/extensor regions (P = 0.000 for both). Furthermore, the maximum increase in grip strength were 0.5 (10.8% increase, P = 0.001) and 1.5 h (23.9% increase, P = 0.000) after taping in males and females, respectively.Conclusions:Taping the extensor region of forearm is recommended to achieve higher grip strength. Although grip strength increased at a slower pace in females than males, the final values were higher in women.