Low Power Processor Architectures and Contemporary Techniques for Power Optimization – A Review

The technological evolution has increased the number of transistors for a given die area significantly and increased the switching speed from few MHz to GHz range. Such inversely proportional decline in size and boost in performance consequently demands shrinking of supply voltage and effective power dissipation in chips with millions of transistors. This has triggered substantial amount of research in power reduction techniques into almost every aspect of the chip and particularly the processor cores contained in the chip. This paper presents an overview of techniques for achieving the power efficiency mainly at the processor core level but also visits related domains such as buses and memories. There are various processor parameters and features such as supply voltage, clock frequency, cache and pipelining which can be optimized to reduce the power consumption of the processor. This paper discusses various ways in which these parameters can be optimized. Also, emerging power efficient processor architectures are overviewed and research activities are discussed which should help reader identify how these factors in a processor contribute to power consumption. Some of these concepts have been already established whereas others are still active research areas. © 2009 ACADEMY PUBLISHER

Space closing versus space opening for bilateral missing upper laterals - aesthetic judgments of laypeople: a web-based survey.

OBJECTIVE: To investigate the opinions of laypeople regarding the aesthetic outcome of treating patients with developmental absence of both maxillary lateral incisors using either orthodontic space closure (OSC) or space opening and prosthetic replacement (PR). DESIGN: Cross sectional, web-based survey. METHODS: A panel of five orthodontists and five restorative dentists examined post-treatment intra-oral images of 21 patients with developmental absence of both upper lateral incisors. A consensus view was obtained about the 10 most attractive images (5 OSC; 5 PR). The 10 selected images were used in a web-based survey involving staff and students at the University of Sheffield. In the first section, the participants were asked to evaluate the attractiveness of the 10 randomly arranged single images using a 5-point Likert scale. In the second section, an image of OSC was paired with an image of PR according to their attractiveness ranking by the clinician panel, and the participants were asked to indicate which of the two images they preferred. RESULTS: The survey received 959 completed responses with 9590 judgements. The images of OSC were perceived to be more attractive (mean rating 3·34 out of 5; SD 0·56) compared with the images of PR (mean rating 3·14 out of 5; SD 0·58) (mean diff 0·21; P < 0·001). Female and staff judges tended to give higher attractiveness ratings. Both females and males preferred the OSC images closing in 3 out of 4 paired images. CONCLUSION: Space closing was perceived to be more attractive than space opening by lay people. The findings have implications for advising patients about the best aesthetic outcome when both maxillary lateral incisors are missing

Characterization of transport and magnetic properties in thin film La(0.67)(Ca(x)Sr(1-x))(0.33)MnO(3) mixtures

We have grown thin films of (100) oriented La_{0.67}(Ca_{x}Sr_{1-x})_{0.33}MnO_{3} on (100) NdGaO_{3} substrates by off-axis sputtering. We have looked at the changes in the resistivity and magnetoresistance of the samples as the Ca/Sr ratio was varied. We find that as the calcium fraction is decreased, the lattice match to the substrate decreases, and the films become more disordered, as observed in transport measurements and the variation in Curie and peak resistance temperatures. We find a correlation between the temperature independent and T^2 terms to the low temperature resistivity. The room temperature magnetoresistance exhibits a maximum as the peak temperature is increased by the substitution of Sr for Ca, and a change in the field dependence to the resistivity at room temperature is observed.Comment: 5 pages, 6 eps figures, to be published in Journal of Applied Physic

Activation of Adenylyl Cyclase Reduces TGF-b Profibrotic Response in Osteoarthritic Fibroblast-like Synoviocytes

Purpose: The hallmarks of osteoarthritis (OA) include cartilage degeneration, bone remodeling and synovial fibrosis. Synovial fibrosis is characterized by excessive extracellular matrix (ECM) accumulation due to an imbalance in ECM production, in particular collagen, and its turnover. Transforming growth factor beta (TGF-β) and its associated signaling pathway mediated by ALK5, plays an important role in synovial fibrosis and blocking TGF-β’s effect prevents synovial fibrosis. Increasing intracellular cyclic AMP (cAMP) produces an antifibrotic effect in fibroblasts of multiple origins. Forskolin (FsK) is a naturally occurring diterpene in the roots of the Indian Coleus plant that activates adenylyl cyclase resulting in an elevation in intracellular cAMP levels. We hypothesized that FsK treatment results in an anti-fibrotic effect in TGF-β stimulated fibroblast-like synoviocytes (FLS) from patients with advanced OA. Methods: OA FLS (Cell Applications, USA) were harvested from patients undergoing total knee replacement. Cells were used between the 3rd and 6th passages for all experiments. OA FLS (300,000 cells per well) were treated with TGF-β (1ng/ml; R&D Systems) in the absence or presence of FsK (10μM; Sigma Aldrich) or SB431542, an ALK5 inhibitor (1μM, Sigma Aldrich) for 24 hours followed by RNA extraction using Trizol reagent and RNA concentrations were determined using a NanoDrop ND-2000 spectrophotometer. cDNA was synthesized using iScript Reverse Transcription Supermix for RT-qPCR (Bio-Rad, USA). Quantitative PCR (qPCR) was performed using TaqMan Fast Advanced Master Mix (Lifetechnologies, USA). The cycle threshold (Ct) value of genes of interest were normalized to the Ct value of GAPDH in the same sample, and the relative expression was calculated using the 2−ΔΔCt method. Genes of interest included collagens type 1 (COL1A1) and 3 (COL3A1), α2 smooth muscle actin (ACTA2), proteoglycan-4 (PRG4), matrix metalloproteinases 3, 9 and 13 (MMP3, MMP9 and MMP13), tissue inhibitor of metalloproteinase-1 (TIMP1) and aggrecanase-1 (ADAMTS4). Multiple group comparisons were performed by ANOVA or ANOVA on the ranks followed by pairwise group comparisons using Tukey\u27s test. Data is presented as the average ± S.D. of 3–6 independent experiments. Results:FsK treatment significantly reduced TGF-β induced expression of collagen type I (fig. 1A; p Conclusions: Using a model of TGF-β stimulated OA synovial fibroblasts, FsK treatment resulted in a reduction in the expression of collagen type I, a major component of fibrosis and α2 smooth muscle actin, a marker of fibroblast differentiation to myofibroblasts. To this end, FsK\u27s effect was comparable to the inhibition of intracellular TGF-β signaling. PRG4 regulates synovial proliferation and inflammation and FsK treatment enhanced PRG4 expression by OA fibroblasts. FsK reduced expression of matrix degrading enzymes, especially MMP3 and MMP9 involved in synovial proliferation, and MMP13 and ADAMTS4, involved in cartilage degradation. Increasing intracellular levels of cAMP in synovial fibroblasts may result in antifibrotic and chondroprotective effects in the joint

Sequence comparison and phylogenetic analysis of core gene of hepatitis C virus from Pakistani population

In Pakistan, more than 10 million people are living with hepatitis C virus (HCV) with high morbidity and mortality. The aims of the present study are to report HCV core gene sequences from Pakistani population and perform their sequence comparison/phylogenetic analysis. The core gene of HCV has been cloned from six different patients and sequences submitted at the National Center of Biotechnology Information (NCBI). Nucleotides and deduced amino acid sequence comparison of six isolates was performed with each other and with two HCV genotype 3a type examples reported from Japan. Phylogenetic tree of HCV core sequences was constructed using CLC software. Nucleotides sequence comparison showed that our sequences have 94 to 96% homology with NZL1 strain and 90 to 93%homology with HCV-K3A/650 strain. Deduced amino acid sequence comparison showed that our sequences have 92 to 98% homology with NZL1 strain and 88 to 94% homology with HCV-K3A/650 strain.Phylogenetic analysis suggests that our sequences are clustered with sequences reported from Japan. This is the first phylogenetic analysis of HCV core gene from Pakistani population. Our sequences and sequences from Japan are grouped into same cluster in the phylogenetic tree. Sequence comparison and phylogenetic analysis showed that our isolates have high homology with Japanese isolates

Effect of vitamin A supplementation in category-I Pulmonary Tuberculosis patients in a Medical College in India: a rapid assessment analysis

Background: Tuberculosis is one of the major health problems affecting the global population causing immense morbidity and mortality. Studies have shown that a good antioxidant status of the body has immune protective role against tuberculosis and may be associated with a decreased risk of the disease and slower rate of progression. Objective of the study was planned to evaluate the beneficial effects of Vitamin A as add on therapy to the standard drug therapy in patients with sputum positive pulmonary tuberculosis.Methods: The study was done in a Tuberculosis clinic, Department of Internal Medicine, Stanley Medical College for duration of 6 months. All the newly diagnosed sputum positive pulmonary tuberculosis patients (18-55 years) attending the outpatient were taken for the study purpose. A Phase III, prospective, open, two arm parallel group, outpatient, randomized, active controlled study was done.Results: After two weeks of therapy, the number of patients with negative sputum smear was higher in the study group than the control group. Vitamin A supplementation resulted in an earlier elimination of tubercle bacilli from the sputum.Conclusions: This study shows that vitamin A as add on therapy to the existing standard therapy improves the clinical response and decreases the disease activity to a greater extent than with routine standard therapy alone

A comparative study of mebeverine and synbiotic combination in patients with diarrhoea predominant Irritable Bowel Syndrome in a Medical College in South India

Background: Irritable bowel syndrome (IBS) is a chronic, episodic functional gastrointestinal disorder characterized by abdominal pain / discomfort and altered bowel habits. Though it is considered as a functional disorder, the burden of the disease to the patients is very high and the quality of life becomes miserable. Currently available IBS therapies are mainly symptom oriented and have limited efficacy. Various studies had done so far which provide a clear rationale for the use of Synbiotic in this disorder. The objective of the study includes, this study was planned to compare the efficacy of Mebeverine + Synbiotic combination with Mebeverine and Synbiotic monotherapy in patients with diarrhoea predominant irritable bowel syndrome.Methods: The study was done in Department of Medical Gastroenterology, Rajiv Gandhi Government Hospital, Chennai for duration of one year. Patients with Irritable Bowel Syndrome (diarrhea predominant type), diagnosed within 1 year and attending outpatient department were taken. A randomized, Phase III, prospective, interventional, open label, outpatient, comparative study design was done. A total of 60 patients divided into 3 groups were finally selected for the study purpose.Results: Twelve weeks after completion of active drug therapy, the Mebeverine + Synbiotic combination improved all the symptoms of IBS except abdominal pain. Further it was evident that combination therapy had significant remission in stool frequency and consistency when compared with other groups.Conclusions: Combination of Mebeverine + Synbiotic is more effective in improving most of the troublesome symptoms in patients with diarrhea predominant irritable bowel syndrome than other therapies and also in maintaining remission, in terms of frequency and consistency of stools

Angiotensin-(1-7) receptor Mas deficiency does not exacerbate cardiac atrophy following high-level spinal cord injury in mice

Experimental spinal cord injury (SCI) causes a morphological and functional deterioration of the heart, in which the renin–angiotensin system (RAS) might play a role. The recently discovered non-canonical axis of RAS with angiotensin-(1-7) and its receptor Mas, which is associated with cardioprotection could be essential to prevent damage to the heart following SCI. We investigated the cardiac consequences of SCI and the role of Mas in female wild-type (WT, n = 22) and mice deficient of Mas (Mas(-/-), n = 25) which underwent spinal cord transection at thoracic level T4 (T4-Tx) or sham-operation by echocardiography (0, 7, 21, and 28 days post-SCI), histology and gene expression analysis at 1 or 2 months post-SCI. We found left ventricular mass reduction with preserved ejection fraction (EF) and fractional shortening in WT as well as Mas(-/-) mice. Cardiac output was reduced in Mas(-/-) mice, whereas stroke volume (SV) was reduced in WT T4-Tx mice. Echocardiographic indices did not differ between the genotypes. Smaller heart weight (HW) and smaller cardiomyocyte diameter at 1 month post-SCI compared to sham mice was independent of genotype. The muscle-specific E3 ubiquitin ligases Atrogin-1/MAFbx and MuRF1 were upregulated or showed a trend for upregulation in WT mice at 2 months post-SCI, respectively. Angiotensinogen gene expression was upregulated at 1 month post-SCI and angiotensin II receptor type 2 downregulated at 2 month post-SCI in Mas(-/-) mice. Mas was downregulated post-SCI. Cardiac atrophy following SCI, not exacerbated by lack of Mas, is a physiological reaction as there were no signs of cardiac pathology and dysfunction