A novel frequency compensation technique for low-voltage low-dropout regulator

A novel frequency compensation technique for low-voltage low-dropout regulator (LDR) is presented. The proposed technique, called pole-control frequency compensation (PCFC), provides faster loop response and does not require a large filtering capacitor. Both theoretical analysis and simulation show that the stability of the LDR using PCFC is independent of the load current, temperature and equivalent series resistance of the filtering capacitor. It is well suited for LDRs inside portable equipment such as cellular phones, pagers and personal digital assistance

Optimum nested Miller compensation for low-voltage low-power CMOS amplifier design

An optimum structure of nested Miller compensation (NMC) is developed, The developed structure using feed-forward transconductance stage and null resistor on NMC, called NMCFNR, solves the bandwidth reduction and poor transient response problems of low-voltage low-power NMC amplifiers. For comparison, amplifiers compensated by NMC and NMCFMR have been fabricated. Experimental results show that NMCFNR improves the gain-bandwidth product, slew rate and settling time by more than three times with 8 degrees increase on the phase margin and no increase on the power consumption. Moreover, it improves the negative power supply rejection ratio by at least 54dB. The die area of the NMCFNR amplifier is about hall of that of the NMC amplifier

Osthole: A Review on Its Bioactivities, Pharmacological Properties, and Potential as Alternative Medicine

This paper reviews the latest understanding of biological and pharmacological properties of osthole (7-methoxy-8-(3-methyl-2-butenyl)-2H-1-benzopyran-2-one), a natural product found in several medicinal plants such as Cnidium monnieri and Angelica pubescens. In vitro and in vivo experimental results have revealed that osthole demonstrates multiple pharmacological actions including neuroprotective, osteogenic, immunomodulatory, anticancer, hepatoprotective, cardiovascular protective, and antimicrobial activities. In addition, pharmacokinetic studies showed osthole uptake and utilization are fast and efficient in body. Moreover, the mechanisms of multiple pharmacological activities of osthole are very likely related to the modulatory effect on cyclic adenosine monophosphate (cAMP) and cyclic adenosine monophosphate (cGMP) level, though some mechanisms remain unclear. This review aims to summarize the pharmacological properties of osthole and give an overview of the underlying mechanisms, which showcase its potential as a multitarget alternative medicine

A mini-review of traditional Chinese medicines on liver diseases

Introduction: Currently, around 2 million deaths per year are attributed to liver disorders worldwide. There are many traditional Chinese medicines (TCM) and natural products used for preventing and combating liver disorders in China, such as “Celastrol”, “Astragalus”, and “Curcumin”. This mini-review aims to discuss the (i) TCM theory, (ii) pharmacology mechanisms, and (iii) toxicology of the commonly used TCMs, such as “Celastrol”, “Astragalus”, “Curcumin” in the treatment of liver diseases, and further (iv) describe the help of modern “Nanotechnology” with these TCMs in future development for curing liver diseases. Methods: Nine electronic databases were searched between 2012 and 2022, including WanFang Data, PubMed, Science Direct, Scopus, Web of Science, Springer Link, SciFinder, and China National Knowledge Infrastructure (CNKI), without regard to language constraints. The searched keywords include “Celastrol + liver diseases”, “Astragalus + liver disease” ''Curcumin + liver diseases'', etc. All eligible studies are analyzed and summarized in this review. Results: Celastrol, Astragalus, and Curcumin were reported to be effective Chinese herbals for the prevention and treatment of liver diseases through cyclic adenylate monophosphate (cAMP)–protein kinase A (PKA)–nuclear factor kappa-B (NF-κB), miR-712-PPAR-γ-PI3K/AKT-GLUT4, and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of the rapamycin (mTOR) signaling pathways. Nanoformulations could improve physiochemical features and enhance the efficacy of Chinese herbs. Conclusion: Celastrol, Astragalus, and Curcumin as commonly used TCMs for the treatment of liver diseases possess a wide extent of pharmacological functions, such as anti-inflammatory, anti-oxidant, and anti-cancer properties. Nanoformulations of Chinese herbs show great promise in the development of traditional Chinese medicines for treating liver diseases

“Qigong” Mind-Body Exercise for Elderly Care

Letter to Editor on “Qigong” Mind-Body Exercise for Elderly Care by Siu Kan Law, Dawn Ching Tung Au, Albert Wing Nang Leung, Chuan Shan Xu.&nbsp

"TaiChi" Exercise for Elderly Care

Letter to Editor titled "TaiChi" Exercise for Elderly Car

Icaritin Inhibits Collagen Degradation-Related Factors and Facilitates Collagen Accumulation in Atherosclerotic Lesions: A Potential Action for Plaque Stabilization

Most acute coronary syndromes result from rupture of vulnerable atherosclerotic plaques. The collagen content of plaques may critically affect plaque stability. This study tested whether Icaritin (ICT), an intestinal metabolite of Epimedium-derived flavonoids, could alter the collagen synthesis/degradation balance in atherosclerotic lesions. Rabbits were fed with an atherogenic diet for four months. Oral administration of ICT (10 mg·kg−1·day−1) was started after two months of an atherogenic diet and lasted for two months. The collagen degradation-related parameters, including macrophages accumulation, content and activity of interstitial collagenase-1 (MMP-1), and the collagen synthesis-related parameters, including amount and distribution of smooth muscle cells (SMC) and collagen mRNA/protein levels, were evaluated in the aorta. ICT reduced plasma lipid levels, inhibited macrophage accumulation, lowered MMP-1 mRNA and protein expression, and suppressed proteolytic activity of pro-MMP-1 and MMP-1 in the aorta. ICT changed the distribution of the SMCs towards the fibrous cap of lesions without increasing the amount of SMCs. Higher collagen protein content in lesions and aorta homogenates was observed with ICT treatment compared with the atherogenic diet only, without altered collagen mRNA level. These results suggest that ICT could inhibit the collagen degradation-related factors and facilitate collagen accumulation in atherosclerotic lesions, indicating a new potential of ICT in atherosclerotic plaques

Elderly for Dementia - “Mahjong”

Short Commentary titled: Elderly for Dementia - “Mahjong

Three-stage large capacitive load amplifier with damping-factor-control frequency compensation

A novel damping-factor-control frequency compensation (DFCFC) technique is presented in this paper with detailed theoretical analysis, This compensation technique improves frequency response, transient response, and power supply rejection for amplifiers, especially when driving large capacitive loads. Moreover, the required compensation capacitors are small and can be easily integrated in commercial CMOS process. Amplifiers using DFCFC and nested Miller compensation (NMC) driving two capacitive loads, 100 and 1000 pF, were fabricated using a 0.8 mu m CMOS process with V-m = 0.72 V and V-tp = -0.75 V, For the DFCFC amplifier driving a 1000-pF load, a 1-MHz gain-bandwidth product, 51 degrees phase margin, 0.33-V/mu s slew rate, 3.54-mu s settling time, and 426-mu W power consumption are obtained with integrated compensation capacitors. Compared to the NMC amplifier, the frequency and transient responses of the DFCFC amplifier are improved by one order of magnitude with insignificant increase on the power consumption

Frequency compensation techniques for low-power multistage amplifiers

A three stage amplifier is disclosed provided with a novel frequency compensation technique. Only a single feedback loop with a single compensation capacitance is provided. Instead of a conventional nested compensation technique, damping factor control is provided by means of a fourth gain stage in order to stabilize the amplifier. The resulting amplifier is particularly useful to drive large capacitive loads for low-voltage low-power applications