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A growing number of patients with obstructive colorectal cancer are being treated with self-expanding metallic stents (SEMS) followed by laparoscopic resection. The aim of this study was to assess the feasibility of stent insertion and laparoscopic surgery for obstructive colorectal cancer and to compare these outcomes to regular laparoscopic surgery for non-obstructive colorectal cancer.We retrospectively analyzed the outcomes of patients with a malignant colonic obstruction who underwent SEMS placement followed by elective laparoscopic resection. The comparison was made between stent-laparoscopy and laparoscopy alone for non-obstructive colorectal cancer.Colonic stenting as a bridge to surgery was successful in 97.1% of all cases. Fifteen patients underwent an elective laparoscopic surgery for left-sided colon and rectal cancer after SEMS. The mean interval from SEMS insertion to laparoscopic surgery was 21.5 days. There was no conversion to open surgery and no need for a diverting stoma. One patient (6.7%) experienced paralytic ileus. Our comparison of stent-laparoscopy to regular laparoscopy for non-obstructive colorectal cancer treatment showed comparable short-term postoperative outcomes with the exception of blood loss, which was greater in the stent-laparoscopy group.Elective laparoscopic surgery after colonic stenting is a safe and feasible strategy for the treatment of an acute malignant colonic obstruction.

BACKGROUND According to troponin-based criteria of myocardial infarction (MI), patients without elevation of creatine kinase (CK), formerly classified as unstable angina (UA), are now diagnosed as non-ST-elevation MI (NSTEMI), but little is known about their outcomes.Methods and Results:Between July 2012 and March 2014, 3,283 consecutive patients with MI were enrolled. Clinical follow-up data were obtained up to 3 years. The primary endpoint was a composite of all-cause death, non-fatal MI, non-fatal stroke, cardiac failure and urgent revascularization for UA. There were 2,262 patients with ST-elevation MI (STEMI), 563 NSTEMI with CK elevation (NSTEMI+CK) and 458 NSTEMI without CK elevation (NSTEMI-CK). From day 0, Kaplan-Meier curves for the primary endpoint began to diverge in favor of NSTEMI-CK for up to 30 days. The 30-day event rate was significantly lower in patients with NSTEMI-CK (3.3%) than in STEMI (8.6%, P

BACKGROUND Acute kidney injury (AKI) is associated with poor outcome after acute myocardial infarction (AMI), but whether hemodynamic status at presentation influences this prognostic significance is unknown.Methods and Results:A total of 2,798 AMI patients admitted within 48 h after symptom onset and who underwent urgent coronary angiography were enrolled in the present study. AKI was defined as an increase in serum creatinine ≥0.3 mg/dL or ≥50% within 48 h during hospitalization. Patients were classified into 3 groups according to Killip class on admission: Killip 1, n=2,164; Killip 2-3, n=366; and Killip 4, n=268. AKI occurred more frequently with increasing Killip class (Killip 1, 2-3, and 4: 6.3%, 15.3%, and 31.3%, respectively; P

This study investigated the effect of chemical inhibitors on the cell-cycle synchronisation in cat fibroblast cells and evaluated the development of interspecies embryos reconstructed from cat donor cells and enucleated bovine oocytes. Cat fibroblast cells were treated with 15 μg/mL roscovitine or 0.05 μg/mL deme-colcine prior to cell cycle analysis and nuclear transfer. The percentage of cat fibroblast cells arrested at the G0/G1 phase in the roscovitine group was similar to that in the control group without any treatment. The percentage of cells arrested at the G2/M phase was significantly higher in the demecolcine group than in the control group. The fusion rate of interspecies couplets was significantly greater in the roscovitine group than in the control group. Most embryos stopped the development at the 2- or 4-cell stage, and none developed into blastocysts. Chemical inhibitor-induced donor cell cycle synchronisation did not overcome developmental arrest in interspecies cloned embryos.

Structural information about the target-compound complex is invaluable in the early stage of drug discovery. In particular, it is important to know into which part of the initial compound additional interaction sites could be introduced to improve its affinity. Herein, we demonstrate that the affinity of a small-molecule inhibitor for its target protein could be successfully improved by the constructive introduction of the interaction mode of a competitive peptide. The strategy involved the discrimination of overlapping and non-overlapping peptide-compound pharmacophores by the use of a ligand-based NMR spectroscopic approach, INPHARMA. The obtained results enabled the design of a new compound with improved affinity for the platelet receptor glycoprotein VI (GPVI). The approach proposed herein efficiently combines the advantages of compounds and peptides for the development of higher-affinity druglike ligands.

Atrial fibrillation (AF) shares background comorbidities with coronary artery disease (CAD), including hypertension and diabetes mellitus. The aim of the study is to evaluate the prevalence, risk factors, and prognostic significance of CAD among patients who underwent catheter ablation for AF. In 544 consecutive registered patients who underwent catheter ablation for AF (CHADS2 score 1.2 ± 1.1, paroxysmal AF 57%), quantitative coronary angiography was used to detect CAD, defined as luminal narrowing of ≥50% in diameter. Univariate and multiple logistic regression analyses were applied to evaluate the risk factors of CAD. Subsequent clinical events up to 1 year were obtained in all the patients. CAD was found in 70 patients (13%). The factors associated with the presence of CAD in AF patients who underwent catheter ablation were similar to traditional coronary risk factors such as hypertension and diabetes mellitus. AF patients with CAD had a higher CHADS2 score than those without CAD (1.5 ± 1.1 vs 1.1 ± 1.0, p = 0.009). Hence, a CHADS2 score ≥1 may be an alternative risk factor to predict CAD. Previous coronary revascularization (14% with CAD vs 6% without CAD) and paroxysmal AF (69% vs 55%) were also associated with CAD. During follow-up, patients with CAD experienced acute coronary syndrome (n = 2) and coronary revascularization (n = 18); no such events were recorded in those without CAD. In addition to traditional risk factors, CHADS2 score, previous revascularization, and paroxysmal AF may be new risk factors for CAD in AF patients.

Abnormal epigenetic reprogramming, such as histone acetylation, might cause low efficiency of interspecies somatic cell nuclear transfer (iSCNT). This study was conducted to evaluate the effects of trichostatin A (TSA) on the developmental competence and histone acetylation of iSCNT embryos reconstructed from cat somatic cells and bovine cytoplasm. The iSCNT cat and parthenogenetic bovine embryos were treated with various concentrations of TSA (0, 25, 50, or 100 nM) for 24 h, respectively, following fusion and activation. Treatment with 50 nM TSA produced significantly higher rates of cleavage and blastocyst formation (84.3% and 4.6%, respectively) of iSCNT embryos than the rates of non-TSA–treated iSCNT embryos (63.8% and 0%, respectively). Similarly, the treatment of 50 nM TSA increased the blastocyst formation rate of parthenogenetic bovine embryos. The acetylation levels of histone H3 lysine 9 (H3K9) in the iSCNT embryos with the treatment of 50 nM TSA were similar to those of in vitro–fertilized embryos and significantly higher (p

Cachexia, a negative prognostic factor, worsens a patient's quality of life. We established 2 novel cachexia models with the human stomach cancer cell line MKN-45, which was subcloned to produce potent cachexia-inducing cells by repeating the xenografts in immune-deficient mice. After subsequent xenografts, we isolated potent cachexia-inducing cells (MKN45cl85 and 85As2mLuc). Xenografts of MKN45cl85 cells in mice led to substantial weight loss and reduced adipose tissue and musculature volumes, whereas xenografts of 85As2mLuc cells resulted in highly metastatic and cachectic mice. Surgical removal of tumor tissues helped the mice regain body-weight in both mouse models. In vitro studies using these cells showed that isoflavones reduced their proliferation, implying that the isoflavones possess antiproliferative effects of these cancer cell lines. Isoflavone treatment on the models induced tumor cytostasis, attenuation of cachexia, and prolonged survival whereas discontinuation of the treatment resulted in progressive tumor growth and weight loss. The inhibitory effects of tumor growth and weight loss by isoflavones were graded as soy isoflavone aglycone AglyMax > daidzein > genistein. These results demonstrated that the 2 novel cachectic mouse models appear useful for analyzing the mechanism of cancer cachexia and monitoring the efficacy of anticachectic agents.

Background: Low adiponectin levels and high leptin levels are associated with a high incidence of developing cardiovascular disease. However, the relationship between the levels of these adipokines and the development of adverse events after acute myocardial infarction (AMI) remains unclear. Methods and Results: This study enrolled 724 Japanese subjects with AMI who underwent successful emergency percutaneous coronary intervention (PCI). Their serum adiponectin and leptin levels were measured 7 days after AMI onset. There were 63 adverse events during the 3-year follow-up. The levels of adiponectin and leptin and the leptin to adiponectin ratio, were significantly associated with adverse events [hazard ratio 2.08 (95% confidence interval (CI) 1.33–3.24), P=0.001; hazard ratio 0.62 (95% CI 0.43–0.90), P=0.012; hazard ratio 0.59 (95% CI 0.45–0.76), P

Background Anticoagulation therapy with the vitamin K antagonist (VKA) warfarin has been demonstrated to reduce thromboembolic risk after electrical cardioversion (ECV). However, data concerning ECV with non-VKA oral anticoagulants (NOACs) is limited. The objective of this study was to determine the efficacy and safety of NOACs in patients undergoing ECV in a real-world clinical practice at a single center in Japan. Methods We retrospectively analyzed the data of 406 consecutive patients who underwent ECV for atrial fibrillation (AF) or flutter under anticoagulation with one of the three NOACs ( n =149) or with a VKA ( n =257). Results The CHADS2 and HAS-BLED scores were significantly higher in the VKA group, whereas the NOACs group had a tendency toward greater spontaneous echo contrast grades. After ECV, ischemic stroke occurred in three patients of the VKA group and one patient in the NOAC group, all of whom had persistent AF, indicating no significant difference in the thromboembolic event rate within 30 days following ECV. No other thromboembolic events, major bleeding, or death occurred in either group. Among the NOAC and VKA patients in whom we newly introduced an oral anticoagulant to perform ECV, the number of days leading to ECV was significantly lesser for the NOAC patients. Conclusion NOACs may be used as an alternative to VKAs for ECV and may allow prompt ECV in clinical practices.

The changes triggered by sperm-induced activation of oocytes, which are required for normal oocyte development, can be mediated by other agents, thereby inducing the parthenogenesis. In this study, we exposed porcine oocytes to 1 mM Ca-EDTA, a metal-ion chelator, at various intervals during 48 hr of in vitro maturation to determine the optimum period of Ca-EDTA treatment for parthenogenetic activation. When the oocytes were cultured with or without Ca-EDTA from 36 hr (post-12), 24 hr (post-24), 12 hr (post-36) and 0 hr (post-48) after the start of maturation culture, the blastocyst formation rates were significantly higher (P

Methods and Results: We evaluated 879 AMI patients undergoing successful primary revascularization within 24 h of symptom onset. The patients were classified into 3 groups according to tertiles of plasma VEGF levels at 7 days after the onset of AMI. Major adverse cardiovascular and cerebrovascular events (MACCE), defined as cardiac death, recurrent acute coronary syndrome, hospital readmission for heart failure, or stroke, were assessed during the 6-month follow-up period. The incidence of MACCE was the least frequent in the middle tertile. Compared to the middle tertile, patients in the low tertile were at a significantly higher risk for MACCE even after adjusting for baseline characteristics (hazard ratio [HR] 2.67, 95% confidence interval [CI] 1.18–6.06, P=0.019). An absence of statin treatment before onset and a younger age (HR 0.54, 0.87; 95%CI 0.33–0.90, 0.76–0.99; P=0.017, 0.037; respectively) were significantly associated with low VEGF. Conclusions: Low plasma VEGF levels at 7 days after the onset of AMI were associated with a significantly increased risk for MACCE during 6 months of follow-up.

This report describes a case of paradoxical atrial undersensing by a dual-chamber pacemaker during paroxysmal atrial fibrillation. Undersensing of 5.6mV atrial signals at a programmed sensitivity of 0.5mV returned to normal sensing by decreasing atrial sensitivity to 1.0mV. This uncommon phenomenon can be explained by a repeated activation of the quiet timer blanking interval. Knowledge of this phenomenon is important in the current pacemaker management to improve the accuracy of the diagnostic feature for atrial tachyarrhythmia burden and to avoid unnecessary lead revisions.

A small-size inductive-coupling dc voltage transceiver for highly-parallel wafer-level testing is experimentally demonstrated in 90-nm CMOS technology, which can reduce the total cost of a low-price IC by 18%. In order to carry out dc tests, the proposed transceiver outputs dc voltage to the die-under-test (DUT) without any area-consuming digital circuits. In addition, digital calibration with digital feedback channel which calibrates the output dc voltage enables the removal of calibration circuits on the DUT. All of the circuits for dc tests are implemented into the area of an inductor (100 μm ×100 μm). The proposed dc voltage transmission is successfully demonstrated with 6-bit resolution.

Culture techniques of antral follicle-like structure (AFLS) derived from cumulus-oocyte complexes (COCs) might provide important insights into follicular development and oocyte maturation. This study was undertaken to investigate the effects of embedding bovine COCs individually (one COC) or in groups (4-5 COCs) in collagen gels on the formation of AFLS and the meiotic status of oocytes. The observations of AFLS formation were performed every second day for 14 days. The AFLS was formed at Day 2 or 4 after the start of culture (Day=0), irrespective of the culture methods. The mean diameters of AFLS during Days 4-14 using the individual culture method were significantly higher (p

Acute kidney injury (AKI) is associated with poor outcomes after acute myocardial infarction (AMI); however, its prognostic impacts of AKI on short- and long-term mortality in ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients is

Although the third universal definition of myocardial infarction (MI) distinguishes 5 different types, the clinical features of Type2, including coronary vasospasm (CVS), have been ambiguous due to heterogeneous mechanisms. We sought to compare long-term prognoses in Japanese Type1 and Type2 MI

RhoA is transiently activated by specific extracellular signals such as endothelin-1 (ET-1) in vascular smooth muscle cells. RhoGAP negatively regulates RhoA activity: thus, RhoA becomes the GDP-bound inactive form afterward. Sustained activation of RhoA is induced with high doses of the extracellular signals and is implicated in certain diseases such as vasospasms. However, it remains largely unknown how prolonged activation of RhoA is induced. Here we show that Rho-kinase, an effector of RhoA, phosphorylated p190A RhoGAP at Ser(1150) and attenuated p190A RhoGAP activity in COS7 cells. Binding of Rnd to p190A RhoGAP is thought to enhance its activation. Phosphorylation of p190A RhoGAP by Rho-kinase impaired Rnd binding. Stimulation of vascular smooth muscle cells with a high dose of ET-1 provoked sustained RhoA activation and p190A RhoGAP phosphorylation, both of which were prohibited by a Rho-kinase inhibitor. The phosphomimic mutation of p190A RhoGAP weakened Rnd binding and RhoGAP activities. Taken together, these results suggest that ET-1 induces Rho-kinase activation and subsequent phosphorylation of p190A RhoGAP, leading to prolonged RhoA activation.

We propose a low-power two-port SRAM for real-time video processing that exploits statistical similarity in images. To minimize the discharge power on a read bitline, a majority-logic circuit decides if input data should be inverted in a write cycle, so that ldquo1rdquos are in the majority. In addition, for further power reduction, write-in data are reordered into digit groups from the most significant bit group to the least significant bit group. The measurement result of a 68-kbit video memory in a 90-nm process demonstrates that a 45% power saving is achieved on the read bitline. The speed and area overheads are 4% and 7%, respectively.

We propose a low-power non-precharge-type two-port SRAM for video processing that exploits statistical similarity in images. To minimize the charge/discharge power on a read bitline, the proposed memory cell (MC) has ten transistors (10T), comprised of the conventional 6T MC, a readout inverter and a transmission gate for a read port. In addition, to incorporate three wordlines, we propose a shared wordline structure, with which the vertical cell size of the 10T MC is fitted to the same size as the conventional 8T MC. Since the readout inverter fully charges/discharges a read bitline, there is no precharge circuit on the read bitline. Thus, power is not consumed by precharging, but is consumed only when a readout datum is changed. This feature is suitable to video processing since image data have spatial correlation and similar data are read out in consecutive cycles. As well as the power reduction, the prechargeless structure shortens a cycle time by 38% compared with the conventional SRAM, because it does not require a precharge period. This, in turn, demonstrates that the proposed SRAM operates at a lower voltage, which achieves further power reduction. Compared to the conventional 8T SRAM, the proposed SRAM reduces a charge/discharge possibility to 19% (81% saving) on the bitlines. As the measurement result, we confirmed that the proposed 64-kb video memory in a 90-nm process achieves an 85% power saving on the read bitline, when considered as an H.264 reconstructed image memory. The area overhead is 14.4%.

The M-V launch vehicle of Japan Aerospace Exploration Agency (JAXA) has successfully injected Japan's fifth X-ray space telescope “SUZAKU” into its low earth orbit in this past July. The attitude and vibration control algorithm of the M-V rocket used to be highlighted by its H ∞ robust stability since its first flight conducted in 1997. Beyond this, its robustness character has been further enhanced using the μ -synthesis approach to get better robust characteristics not only in stability but in tracking performance under uncertainty of the system dynamics. The performance has been validated by the latest back-to-back successful flights of the vehicle: in May 2003 to directly inject Japan's first asteroid sample return spaceship “HAYABUSA” into the planned inter-planetary trajectory and in this past July to launch the telescope. The μ -synthesis has been applied for the first time ever for Japan's launcher control beyond the reliable H ∞ design. The plant dynamics has an extremely high-order and unstable characteristics, thus the standard μ -synthesis format cannot be directly applied. The paper gives a unique methodology to apply the theory to such a real high-order complicated system.

A new artificial defect-control technique for reducing the electron-hole recombination times at an electrically active center in order to improve the lifetime of widegap light-emitting diodes is presented. It is proved that by employing the proposed current-pulse operation, the lifetime of devices such as ZnSe white light emitting diodes is improved by 650 times and is longer than that of devices under continuous operation. It is also found that the proposed technique is effective in improving the lifetime of stable GaN ultraviolet light-emitting diodes (LEDs) under accelerated aging conditions.

This paper compares areas between a 6T and 8T SRAM cells, in a dual-Vdd scheme and a dynamic voltage scaling (DVS) scheme. In the dual-Vdd scheme, we predict that the area of the 6T cell keep smaller than that of the 8T cell, over feature technology nodes all down to 32 nm. In contrast, in the DVS scheme, the 8T cell will becomes superior to the 6T cell after the 32-nm node, in terms of the area.

This paper shows that an 8T SRAM cell is superior to a 6T cell in terms of cell area in a future process. At a 65-nm node and later, the 6T cell comprised of the minimum-channel-length transistors cannot make the minimum area because of threshold-voltage variation. In contrast, the 8T cell can employ the optimized transistors and achieves the minimum area even if it is used as a single-port SRAM. In a 32-nm process, the 8T-cell area is smaller than the 6T cell by 14.6% at a supply voltage of 0.8 V. We also discuss the area and access time comparisons between the 6T-SRAM and 8T-SRAM macros.

Temporal fluctuations of spectral shapes have been observed in tip-enhanced Raman scattering (TERS) spectra of adenine molecules. The TERS spectra of a nanocrystalline cluster of adenine molecules showed distinct temporal changes including fluctuations of peak frequencies and peak intensities and extraordinary enhancements of several peaks. The fluctuating TERS signals originate primarily from the molecules in the first layer of the 5 nm thick adenine nanocrystalline cluster. The possible origin of the temporal changes is attributed to the changes of molecular orientation under the metal-coated tip, which is responsible for changing the adsorption angle and the angle of local incident polarization for the molecules adsorbed to the tip. This result suggests the importance of sample−tip interaction at molecular level in the interpretation of TERS spectra and indicates the possibility of the single molecule sensitivity of TERS spectroscopy of DNA base molecules.

今回われわれは, 胃癌を合併した皮膚筋炎の4例を経験したので報告する. 症例1は皮膚筋炎診断後, 9年目に検診で発見された早期胃癌で, 術後皮膚筋炎の病状変化なく, 無再発生存中である. 症例2は間質性肺炎を契機に診断された胃癌合併皮膚筋炎で, 術後間質性肺炎の増悪を認めるも, ステロイドにて軽快し, 現在無再発生存中である. 症例3, 4はともに皮膚症状にて診断された胃癌合併皮膚筋炎で, 症例3は術後に皮膚筋炎症状の改善なく, 術後160日目に死亡, 症例4は術後皮膚筋炎の症状軽快するも, 術後2カ月で多発性肝転移出現し, 術後248日目に死亡した. 悪性腫瘍合併皮膚筋炎は悪性腫瘍切除後に症状軽快するという報告が多いが, 症例によっては手術の意義が乏しい場合もあり, 皮膚筋炎の症状を改善させるために, 安易に手術をするのではなく, 十分に適応を検討する必要がある.

症例は34歳, 男性. 大量の下血を主訴に受診. 腹部所見等では明らかな所見は認めなかったが大腸内視鏡検査により虫垂孔からの出血を認めたため緊急手術を施行した. 術中肉眼所見では炎症性変化や腫瘍性病変を認めず虫垂切除術を施行した. 病理組織学的所見では腫瘍性変化やCrohn病, 血管異形成等の所見を認めなかったが, 潰瘍形成と, その粘膜下に破綻した動脈を認め, 虫垂に発生したDieulafoy潰瘍による出血である可能性も示唆された. 下部消化管出血は日常臨床で比較的高頻度に遭遇するが, 出血部位が虫垂であることは非常に稀であるうえに, 出血の原因自体も興味深い症例であったため文献的考察を加えて報告する.

Aims Left-ventricular (LV) scarring may be associated with a poor response to cardiac resynchronization therapy (CRT). The automatic analysis of myocardial perfusion single-photon emission computed tomography (MP-SPECT) may provide objective quantification of LV scarring. We investigated the impact of LV scarring determined by an automatic analysis of MP-SPECT on short-term LV volume response as well as long-term outcome. Methods and results We studied consecutive 51 patients who were eligible to undergo 99mTc-MIBI MP-SPECT both at baseline and 6 months after CRT (ischaemic cardiomyopathies 31%). Quantitative perfusion SPECT was used to evaluate the defect extent (an index of global scarring) and the LV 17-segment regional uptake ratio (an inverse index of regional scar burden). The primary outcome was the composite of overall mortality or first hospitalization for worsening heart failure. A high global scar burden and a low mid/basal inferolateral regional uptake ratio were associated with volume non-responders to CRT at 6 months. The basal inferolateral regional uptake ratio remained as a predictor of volume non-response after adjusting for the type of cardiomyopathy. During a median follow-up of 36.1 months, the outcome occurred in 28 patients. The patients with a low basal inferolateral regional uptake ratio with a cutoff value of 57% showed poor prognosis (log-rank P = 0.006). Conclusion The scarring determined by automatic analysis of MP-SPECT images may predict a poor response to CRT regardless of the pathogenesis of cardiomyopathy. The basal inferolateral scar burden in particular may have an adverse impact on long-term prognosis.

Purpose: Several studies have reported gender difference in presentation, management and outcome in patients with acute myocardial infarction (AMI). In this study, we focused the impact of age on gender difference in mortality after AMI. Methods: Between July 2012 and March 2014, 3283 patients were admitted to the 28 hospitals participating to the J-MINUET group within 48 hours after the onset of AMI. AMI was diagnosed by universal definition (type 1 or type 2). Patients were divided into 5 strata according to their age: those with age Results: There were 813 women (24.8%). Women were significantly older than men (74.5±11.8 years vs 66.6±12.3 years, P Conclusions: Women had higher in-hospital mortality than men after AMI even in the contemporary troponin era. However, their high mortality was mostly explained by their advanced age.

Fragmin/protamine microparticles (F/P MPs) approximately 0.5-1 µM in diameter were prepared by the simple mixing of fragmin with protamine. This study investigated the effects of F/P MP-containing collagen gels as a hormone carrier on the formation of antral follicle-like structures and on the development of growing bovine oocytes. The supplementation of F/P MPs in collagen gels contributed to the beneficial effects of follicle stimulating hormone (FSH) on the formation and size of antral follicle-like structures. The F/P MPs may serve as potential hormone carriers for the growth of cultured bovine oocytes from early antral follicles.

元・大学院自然科学研究科, 現・神戸大学大学院自然科学研究科, We propose a voltage control scheme for 6T SRAM cells that makes a minimum operation voltage down to 0.3 V under DVS environment. A supply voltage to the memory cells and wordline drivers, bitline voltage, and body bias voltage of load pMOSFETs are controlled according to read and write operations, which secures operation margins even at a low operation voltage. A self-aligned timing control with a dummy wordline and its feedback is also introduced to guarantee stable operation in a wide range of the supply voltage. A measurement result of a 64-kb SRAM in a 90-nm process technology shows that a power reduction of 30 can be achieved at 100 MHz. In a 65-nm 64-Mb SRAM, a 74 power saving is expected at 1/6 of the maximum operating frequency. The performance penalty by the proposed scheme is less than 1, and area overhead is 5.6. Copyright © 2006 The Institute of Electronics, Information and Communication Engineers.