881 results on '"K. Krishnamurthy"'
Search Results
152. The Cys78–Asn88 loop region of the Campylobacter jejuni CstII is essential for α2,3-sialyltransferase activity: analysis of the His85 mutants
- Author
-
Prabhakar, Pradeep Kumar, Rao, K. Krishnamurthy, and Balaji, Petety V.
- Published
- 2014
- Full Text
- View/download PDF
153. hag expression in Bacillus subtilis is both negatively and positively regulated by ScoC
- Author
-
Kodgire, Prashant and Rao, K. Krishnamurthy
- Subjects
Bacillus subtilis -- Physiological aspects ,Bacillus subtilis -- Genetic aspects ,Bacillus subtilis -- Research ,Bacterial proteins -- Physiological aspects ,Bacterial proteins -- Genetic aspects ,Bacterial proteins -- Research ,Genetic regulation -- Research ,Biological sciences - Abstract
In Bacillus subtilis, motility and chemotaxis require the expression of hag, which encodes flagellin. This gene is transcribed by the [[sigma].sup.D] form of RNA polymerase and is regulated by a group of proteins called transition state regulators (TSRs). Our studies show that hag transcription is negatively regulated by the transition state regulator ScoC, by binding to its promoter. Furthermore, ScoC, indirectly, also positively regulates hag by increasing the availability of [[sigma].sup.D] by downregulating the levels of the anti-[[sigma].sup.D]-factor FlgM. We further show that the positive regulation by ScoC predominates over the negative regulation.
- Published
- 2009
154. Glottal source estimation using a sum-of-exponentials model.
- Author
-
Ashok K. Krishnamurthy
- Published
- 1992
- Full Text
- View/download PDF
155. Research Experience For Undergraduates In Micro Mechatronics And Smart Structures
- Author
-
K Krishnamurthy, Stanek, K., and Rao, V.
- Published
- 2020
156. Visioning Transition: A Framework For Collaborative Change
- Author
-
Margarita Takach, Yiyuan J. Zhao, Reza Langari, Ray Taghavi, Mehrdad Ghasemi Nejhad, Luigi Martinelli, Linda Ann Riley, K. Krishnamurthy, Janet M. Twomey, Degang Chen, and David Radcliffe
- Published
- 2020
157. A Dual-Rail Hybrid Analog/Digital LDO with Dynamic Current Steering for Tunable High PSRR and High Efficiency
- Author
-
Krishnan Ravichandran, Scott Chiu, Claudia P Barrera, Rajasekhara M. Narayana Bhatla, Vivek De, James W. Tschanz, Harish K. Krishnamurthy, Zakir K. Ahmed, Xiaosen Liu, and Jing Han
- Subjects
Power supply rejection ratio ,CMOS ,Buck converter ,Computer science ,Voltage control ,Bandwidth (signal processing) ,Electronic engineering ,Chip - Abstract
A dual-rail hybrid analog/digital LDO achieves both high efficiency and tunable high PSRR simultaneously using a dynamic current steering mechanism. Measurements on a 22nm CMOS test chip demonstrate up to −46dB PSRR and 89% efficiency across 0–80mA load from1.8V/1.05V dual-input rails.
- Published
- 2020
158. A SCA-Resistant AES Engine in 14nm CMOS with Time/Frequency-Domain Leakage Suppression using Non-Linear Digital LDO Cascaded with Arithmetic Countermeasures
- Author
-
Sanu Mathew, Harish K. Krishnamurthy, Krishnan Ravichandran, Raghavan Kumar, Vivek De, Himanshu Kaul, Xiaosen Liu, Vikram B. Suresh, and Mark A. Anders
- Subjects
Nonlinear system ,CMOS ,Computer science ,Frequency domain ,Regulator ,Time frequency domain ,Hardware_ARITHMETICANDLOGICSTRUCTURES ,Arithmetic ,Leakage (electronics) - Abstract
An AES engine with uniform side-channel-attack (SCA) resistance across time/frequency domains using a high-bandwidth non-linear digital low-dropout (NL-DLDO) regulator in conjunction with AES arithmetic countermeasures is fabricated in 14nm CMOS. Randomized regulator loop parameters and cascading LDO and arithmetic transformations provide >250K× increase in frequency/time-domain MTD, with no CPA attack detected on current/electromagnetic (EM) traces measured from 1 billion encryptions.
- Published
- 2020
159. An Autonomous Reconfigurable Power Delivery Network (RPDN) for Many-Core SoCs Featuring Dynamic Current Steering
- Author
-
Zakir K. Ahmed, Xiaosen Liu, Chris Schaef, Nachiket Desai, Vivek De, James W. Tschanz, Harish K. Krishnamurthy, Krishnan Ravichandran, and Sheldon Weng
- Subjects
CMOS ,Computer science ,business.industry ,Control theory ,Logic gate ,Embedded system ,Scalability ,Process (computing) ,business ,Inductor ,Efficient energy use ,Power (physics) - Abstract
A 2-input/4-output autonomous RPDN in 14nm CMOS with dynamic current steering enables better core-count and FIVR scalability for many-core SoCs in scaled process nodes while improving the overall area efficiency of on-die power delivery/management circuits by 35%. The RPDN controller minimizes losses for a variety of operating conditions to improve overall energy efficiency in most runtime scenarios while complying with all local and global current limits.
- Published
- 2020
160. Digital Control of Switching and Linear Integrated Voltage Regulators
- Author
-
Vivek De, James W. Tschanz, Xiaosen Liu, Sheldon Weng, Nachiket Desai, Nicolas Butzen, Sally Safwat Amin, Zakir. A Khondker, Harish K. Krishnamurthy, Krishnan Ravichandran, and Kim Suhwan
- Subjects
Analogue electronics ,Buck converter ,Computer science ,Key (cryptography) ,Electronic engineering ,Process (computing) ,Digital control ,State (computer science) ,Voltage regulator ,Variety (cybernetics) - Abstract
This work presents a summary of the digital control techniques in todays advanced, state of the art IVRs and the role digital control is playing to enhance their key performance metrics. Examples from high switching frequency Buck converters, computationally controlled digital LDOs as well as digitally assisted analog and hybrid LDOs speaks not only to the growing popularity of digital control in a wide variety of applications but also demonstrates its suitability on advanced process nodes which is inherently tough on analog circuits.
- Published
- 2020
161. 27.3 EM and Power SCA-Resilient AES-256 in 65nm CMOS Through >350× Current-Domain Signature Attenuation
- Author
-
Arijit Raychowdhury, Josef Danial, Debayan Das, Muya Chang, Harish K. Krishnamurthy, Baibhab Chatterjee, Dong-Hyun Seo, Anupam Golder, Avinash L. Varna, Santosh Ghosh, Sanu Mathew, Shreyas Sen, Nirmoy Modak, and Shovan Maity
- Subjects
business.industry ,Computer science ,Attenuation ,Advanced Encryption Standard ,Electrical engineering ,Regulator ,Voltage regulator ,law.invention ,Capacitor ,CMOS ,law ,business ,Shunt (electrical) ,Leakage (electronics) - Abstract
Computationally-secure cryptographic algorithms when implemented on physical platforms leak critical physical signals correlated with the secret key in the form of power consumption and electromagnetic (EM) emanations. This can be exploited by an adversary, leading to side-channel attacks (SCA) that can recover the secret key. Circuit-level on-chip countermeasures include a switched-capacitor current equalizer [1], charge-recovery logic [2], an integrated voltage regulator (IVR) [3], and an all-digital low-dropout (LDO) regulator [4], which suffer from performance degradation, high power/area overheads because of large embedded passives, as well as EM leakage from large metal-insulator-metal (MIM) capacitor top plates. Alternatively, simulations of shunt LDO-based regulators have been shown to be effective for power SCA resistance [5]. Noting that the correlated current is the source of both power (at supply pin) and EM leakage (radiation throughout current path), this work embraces current-domain ‘signature attenuation’ (CDSA) as a low-overhead generic countermeasure against both EM and power side-channel attacks to achieve the highest minimum traces to disclosure (MTD $> 1\mathrm{B})$ reported to date.
- Published
- 2020
162. Force control of a two-linke planar manipulator with one flexible link.
- Author
-
B.-O. Choi and K. Krishnamurthy
- Published
- 1991
- Full Text
- View/download PDF
163. Pattern of Green Leafhopper Infestation in Boro Rice in Tarai Region of West Bengal Using Distributional and Modular Approach
- Author
-
Bishvajit Bakshi, Pramit Pandit, K. Krishnamurthy, Nripendra Laskar, and Prithwiraj Dey
- Subjects
Leafhopper ,Agronomy ,biology ,Infestation ,medicine ,West bengal ,medicine.disease_cause ,biology.organism_classification - Published
- 2018
164. An experimental study on the effect of nano-clay addition on mechanical and water absorption behaviour of jute fibre reinforced epoxy composites
- Author
-
Rathanasamy Rajasekar, S. Ramakrishnan, K. Krishnamurthy, and G. Rajeshkumar
- Subjects
Absorption of water ,Materials science ,Polymers and Plastics ,Materials Science (miscellaneous) ,02 engineering and technology ,Epoxy ,021001 nanoscience & nanotechnology ,Industrial and Manufacturing Engineering ,020401 chemical engineering ,visual_art ,Nano ,visual_art.visual_art_medium ,Chemical Engineering (miscellaneous) ,0204 chemical engineering ,Jute fibre ,Composite material ,0210 nano-technology - Abstract
This study deals with the investigation of the mechanical and water absorption properties of jute fibre reinforced epoxy composites prepared by using hand layup method. The effects of fibre length (10, 20, 30 and 40 mm), fibre weight fraction (0%, 5%, 10%, 15%, 20% and 25%), concentration of NaOH treatment (5% and 10%) and nano-clay addition (1, 3, 5 and 7 wt%) on the aforementioned properties were determined. Morphological characterisation was performed for the tensile and flexural fractured surface of the specimens to study their microstructural failures. The results revealed that the composites reinforced with 5% of NaOH-treated fibre and 5 wt% of nano-clay exhibited higher tensile, flexural and impact strengths of 103.05 MPa, 162.8 MPa and 0.358 kJ/mm2 respectively, and lower water absorption rate. Moreover, the optimum fibre length and fibre weight fraction were found to be 30 mm and 20% respectively for better overall properties. These composites can be used for light and medium load applications.
- Published
- 2018
165. A Digitally Controlled Fully Integrated Voltage Regulator With 3-D-TSV-Based On-Die Solenoid Inductor With a Planar Magnetic Core for 3-D-Stacked Die Applications in 14-nm Tri-Gate CMOS
- Author
-
Nachiket Desai, Harish K. Krishnamurthy, George E. Mathew, Sheldon Weng, Vivek De, Krishnan Ravichandran, Ruchir Saraswat, and James W. Tschanz
- Subjects
010302 applied physics ,Pulse-frequency modulation ,Materials science ,business.industry ,020208 electrical & electronic engineering ,Energy conversion efficiency ,Solenoid ,02 engineering and technology ,Voltage regulator ,Inductor ,01 natural sciences ,Inductance ,Magnetic core ,CMOS ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Electrical and Electronic Engineering ,business - Abstract
A fully integrated digitally controlled buck voltage regulator, featuring hysteretic and pulse frequency modulation control for maximum light load efficiency, with 3-D through-silicon-via-based on-die solenoid inductor with a planar magnetic core in 14-nm tri-gate CMOS, demonstrates 111 nH/mm2 inductance density and 80% conversion efficiency. The inductance density demonstrated is 20 $\times $ higher than comparable on-die lateral- or spiral-based inductor densities leading to higher light load efficiency.
- Published
- 2018
166. Solubility Enhancement of Diflunisal by Solid Dispersion Techniques
- Author
-
V. P. Pooja, A. C. Neha, K. Krishnamurthy, P. A. Madhuri, and S. D. Akshay
- Subjects
Materials science ,Dispersion (optics) ,medicine ,Thermodynamics ,Diflunisal ,Solubility ,medicine.drug - Published
- 2018
167. Optical studies of AgI–Ag2SO4–TeO2–B2O3 glass system
- Author
-
E. Ramesh Kumar, K. Krishnamurthy Goud, Puli Nageswar Rao, A. Prabhakar Reddy, B. V. Appa Rao, and Chandra Shekhar Reddy Madhireddy
- Subjects
010302 applied physics ,Materials science ,Analytical chemistry ,Field strength ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molar volume ,Polarizability ,0103 physical sciences ,Molar mass distribution ,Direct and indirect band gaps ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Absorption (electromagnetic radiation) ,Refractive index - Abstract
This paper deals with the preparation and optical characterization of xAgI–(100-x)[ 0.444 Ag2SO4–0.555 (0.4TeO2–0.6B2O3) glass system, with x varied from 0 to 70. The prepared glasses were characterized by XRD, FTIR, optical absorption Techniques. Physical parameters like density, average molecular weight, molar volume, refractive index, polarizability, oxygen mol %, Ag+ concentration and field strength were calculated. From the optical absorption studies direct band gap Eg was calculated by correlating Tauc’s and ASF method. Urbach energy Eu was also calculated using optical absorption data. Free energy of the system and second-order deformation potential have also been determined by using relation between Eu and Eg. Variation of these parameters by varying the AgI composition is discussed in detail.
- Published
- 2018
168. Neural Networks for Vector Quantization of Speech and Images.
- Author
-
Ashok K. Krishnamurthy 0001, Stanley C. Ahalt, Douglas E. Melton, and Prakoon Chen
- Published
- 1990
- Full Text
- View/download PDF
169. Competitive learning algorithms for vector quantization.
- Author
-
Stanley C. Ahalt, Ashok K. Krishnamurthy 0001, Prakoon Chen, and Douglas E. Melton
- Published
- 1990
- Full Text
- View/download PDF
170. ScoC and SinR negatively regulate epr by corepression in Bacillus subtilis
- Author
-
Kodgire, Prashant, Dixit, Madhulika, and Rao, K. Krishnamurthy
- Subjects
Bacillus subtilis -- Genetic aspects ,Protein binding -- Research ,Bacterial proteins -- Research ,Biological sciences - Abstract
Negative regulation of epr in Bacillus subtilis 168 is mediated jointly by both ScoC and SinR, which bind to their respective target sites 62 bp apart. Increasing the distance between the two sites abolishes repression, indicating that the two proteins interact, thereby suggesting a mechanism of corepression.
- Published
- 2006
171. epr is transcribed from a sigma(sup)D promoter and is involved in swarming of Bacillus subtilis
- Author
-
Dixit, Madhulika, Murudkar, Charuta S., and Rao, K. Krishnamurthy
- Subjects
Bacteria -- Motility ,Genetic transcription -- Analysis ,Proteases -- Physiological aspects ,Biological sciences - Abstract
Bacillus subtilis 168 motility is regulated by epr gene encoded protease and disruption of epr abolishes swarming activity. Data indicate that chemotaxis and motility gene transcription related RNA polymerase transcribes epr.
- Published
- 2002
172. Dysregulation of hyaluronan homeostasis during aortic valve disease
- Author
-
K. Jane Grande-Allen, Andrew J. Stout, Brittany Matuska, Varun K. Krishnamurthy, Matthew C. Sapp, and Mark E. Lauer
- Subjects
0301 basic medicine ,Aortic valve ,MAPK/ERK pathway ,Pathology ,medicine.medical_specialty ,Adolescent ,Swine ,Heart Valve Diseases ,Dioxoles ,030204 cardiovascular system & hematology ,Biology ,Interstitial cell ,Transforming Growth Factor beta1 ,Pathogenesis ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Nitriles ,Butadienes ,medicine ,Animals ,Homeostasis ,Humans ,Gene Regulatory Networks ,Hyaluronic Acid ,Receptor ,Molecular Biology ,Cells, Cultured ,Aged ,Transforming growth factor beta ,Middle Aged ,Disease Models, Animal ,030104 developmental biology ,medicine.anatomical_structure ,Aortic Valve ,Benzamides ,biology.protein ,Immunohistochemistry ,Cell Adhesion Molecules - Abstract
Aortic valve disease (AVD) is one of the leading causes of cardiovascular mortality. Abnormal expression of hyaluronan (HA) and its synthesizing/degrading enzymes have been observed during latent AVD however, the mechanism of impaired HA homeostasis prior to and after the onset of AVD remains unexplored. Transforming growth factor beta (TGFβ) pathway defects and biomechanical dysfunction are hallmarks of AVD, however their association with altered HA regulation is understudied. Expression of HA homeostatic markers was evaluated in diseased human aortic valves and TGFβ1-cultured porcine aortic valve tissues using histology, immunohistochemistry and Western blotting. Further, porcine valve interstitial cell cultures were stretched (using Flexcell) and simultaneously treated with exogenous TGFβ1±inhibitors for activated Smad2/3 (SB431542) and ERK1/2 (U0126) pathways, and differential HA regulation was assessed using qRT-PCR. Pathological heavy chain HA together with abnormal regional expression of the enzymes HAS2, HYAL1, KIAA1199, TSG6 and IαI was demonstrated in calcified valve tissues identifying the collapse of HA homeostatic machinery during human AVD. Heightened TSG6 activity likely preceded the end-stage of disease, with the existence of a transitional, pre-calcific phase characterized by HA dysregulation. TGFβ1 elicited a fibrotic remodeling response in porcine aortic valves similar to human disease pathology, with increased collagen and HYAL to HAS ratio, and site-specific abnormalities in the expression of CD44 and RHAMM receptors. Further in these porcine valves, expression of HAS2 and HYAL1 was found to be differentially regulated by the Smad2/3 and ERK1/2 pathways, and CD44 expression was highly responsive to biomechanical strain. Leveraging the regulatory pathways that control both HA maintenance in normal valves and early postnatal dysregulation of HA homeostasis during disease may identify new mechanistic insight into AVD pathogenesis.
- Published
- 2017
173. Dry Sliding Wear Behavior of Aluminum 6063 Composites Reinforced with TiB2 Particles
- Author
-
Mengistu Ashebre, K. Krishnamurthy, B. Suresha, and J. Venkatesh
- Subjects
chemistry.chemical_classification ,Materials science ,Base (chemistry) ,Scanning electron microscope ,Metallurgy ,Alloy ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Wear resistance ,chemistry.chemical_compound ,020303 mechanical engineering & transports ,Brinell scale ,0203 mechanical engineering ,chemistry ,engineering ,6063 aluminium alloy ,Composite material ,0210 nano-technology ,Titanium diboride ,Sliding wear - Abstract
The influence of titanium diboride (TiB2) loading on the dry sliding wear characteristics of aluminum 6063 matrix alloy-titanium diboride (Al/TiB2) composite materials has been assessed using a pin-on disc wear tester at different loads. The composites with 5 and 10 wt% of fine TiB2 particles were fabricated using stir casting technique. For comparison, as-cast of the base alloy were made under the same processing applied for Al/TiB2 composites. The hardness of the composite materials was measured using Brinell hardness tester. Scanning electron microscopy (SEM) was used to analyze the wear surfaces of samples. The results indicate that fine TiB2 particles markedly improved the wear performance of the aluminum 6063 matrix alloy. The coefficient of friction decreases with increase in the amount of TiB2, but this effect was more pronounced in dry sliding. Hardness of composites increased with increasing TiB2 loading. The wear rates increase with increase in load and dependent upon TiB2 loading in the base alloy. Among the composites tested, Al/TiB2 composites containing 10 wt% TiB2 exhibited superior wear resistance over the base alloy and 5 wt% Al/TiB2 composites. These observations were correlated in terms of the TiB2 loading in base alloy which resulted in the variations of the hardness.
- Published
- 2017
174. Hypoxia Stimulates Synthesis of Neutrophil Gelatinase-Associated Lipocalin in Aortic Valve Disease
- Author
-
Swetha Sridhar, Ganesh Swaminathan, Varun K. Krishnamurthy, K. Jane Grande-Allen, Denise C Robson, and Yao Ning
- Subjects
0301 basic medicine ,Aortic valve ,lcsh:Diseases of the circulatory (Cardiovascular) system ,Pathology ,medicine.medical_specialty ,elastin ,Cardiovascular Medicine ,030204 cardiovascular system & hematology ,Matrix metalloproteinase ,MMP9 ,Extracellular matrix ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Gelatinase ,Original Research ,biology ,hypoxia ,business.industry ,neutrophil gelatinase-associated lipocalin ,aortic valve disease ,Hypoxia (medical) ,030104 developmental biology ,medicine.anatomical_structure ,lcsh:RC666-701 ,cardiovascular system ,biology.protein ,medicine.symptom ,valve interstitial cells ,Cardiology and Cardiovascular Medicine ,business ,Elastin ,Homeostasis - Abstract
Objective: Aortic valve disease is commonly found in the elderly population. It is characterized by dysregulated extracellular matrix remodeling followed by extensive microcalcification of the aortic valve and activation of valve interstitial cells. The mechanism behind these events are largely unknown. Studies have reported expression of hypoxia inducible factor-1 alpha (HIF1α) in calcific nodules in aortic valve disease, therefore we investigated the effect of hypoxia on extracellular matrix remodeling in aged aortic valves. Approach and Results: Western blotting revealed elevated expression of HIF1α and the complex of matrix metalloprotease 9 (MMP9) and neutrophil gelatinase-associated lipocalin (NGAL) in aged porcine aortic valves cultured under hypoxic conditions. Consistently, immunofluorescence staining showed co-expression of MMP9 and NGAL in the fibrosa layer of these porcine hypoxic aortic valves. Gelatinase zymography demonstrated that the activity of MMP9-NGAL complex was significantly increased in aortic valves in 13% O2 compared to 20% O2. Importantly, the presence of ectopic elastic fibers in the fibrosa of hypoxic aortic valves, also detected in human diseased aortic valves, suggests altered elastin homeostasis due to hypoxia. Conclusion: This study demonstrates that hypoxia stimulates pathological extracellular matrix remodeling via expression of NGAL and MMP9 by valve interstitial cells.
- Published
- 2019
175. A Variation-Adaptive Integrated Computational Digital LDO in 22nm CMOS with Fast Transient Response
- Author
-
Charles Augustine, James W. Tschanz, Khondker Zakir Ahmed, Krishnan Ravichandran, Harish K. Krishnamurthy, Sheldon Weng, Xiaosen Liu, and Vivek De
- Subjects
Low-dropout regulator ,Dynamic voltage frequency scaling ,Settling time ,Computer science ,Regulator ,Hardware_PERFORMANCEANDRELIABILITY ,law.invention ,Power (physics) ,Capacitor ,CMOS ,law ,Control theory ,Voltage droop ,Transient response ,Transient (oscillation) ,Electrical and Electronic Engineering ,Infinite impulse response ,Voltage - Abstract
A variation-adaptive computational digital low dropout (CDLDO) regulator featuring an event-driven computational controller (CC) is presented, which computes the required number of power gates (PGs) unlike the traditional IIR filter-based control techniques to regulate the output voltage for any load/reference transient. The CC ensures ~ns transient response with a deterministic two-event duration settling time, independent of the dynamic range of the load or output capacitor value. Measurement results of a 10-bit PG design demonstrate a droop of 100 mV for 500 mA (2 A/ns $di/dt$ ) with settling times < 20 ns. The CDLDO design is presented with the key equations and timing diagrams to show the operating principle of the concept. Methods to accommodate resiliency to process, voltage and temperature (PVT) and wide dynamic voltage frequency scaling (DVFS) conditions are also discussed in detail.
- Published
- 2019
176. 14.7 A Modular Hybrid LDO with Fast Load-Transient Response and Programmable PSRR in 14nm CMOS Featuring Dynamic Clamp Tuning and Time-Constant Compensation
- Author
-
Taesik Na, Harish K. Krishnamurthy, Vivek De, Khondker Zakir Ahmed, Sheldon Weng, James W. Tschanz, Xiaosen Liu, and Krishnan Ravichandran
- Subjects
Power supply rejection ratio ,Analogue electronics ,Computer science ,business.industry ,020208 electrical & electronic engineering ,Ripple ,Time constant ,Electrical engineering ,020206 networking & telecommunications ,Hardware_PERFORMANCEANDRELIABILITY ,02 engineering and technology ,CMOS ,Hardware_INTEGRATEDCIRCUITS ,0202 electrical engineering, electronic engineering, information engineering ,Static random-access memory ,Transient response ,Transceiver ,business ,Decoupling (electronics) ,Voltage - Abstract
Complex SoCs in scaled CMOS processes integrate a large variety of digital, SRAM and noise-sensitive mixed-signal/analog circuit blocks such as PLLs, wireline/wireless/RF transceivers, sensor front-ends, etc. The on-die low-dropout regulators (LDO) used for fine-grain DVFS of digital and memory blocks must respond fast to large load transients to minimize voltage droops/overshoots without using large decoupling caps, while minimizing power overheads over a wide operating range. The noise-sensitive analog circuits, on the other hand, need LDOs that provide sufficiently high power supply rejection (PSR) and minimal output voltage ripple, while maximizing current efficiency. Fast and scalable digital (DLDO) [1], analog-assisted digital (AA-DLDO) [2]–[3] and hybrid (HLDO) [4] analog-digital LDOs targeted for digital and memory blocks, as well as high-PSRR analog LDOs (ALDO) [5] optimized specifically for analog circuits have been recently reported.
- Published
- 2019
177. 8.5 A Fully Integrated Voltage Regulator in 14nm CMOS with Package-Embedded Air-Core Inductor Featuring Self-Trimmed, Digitally Controlled Variable On-Time Discontinuous Conduction Mode Operation
- Author
-
James W. Tschanz, Kaladhar Radhakrishnan, Vivek De, Nachiket Desai, Christopher Schaef, Sheldon Weng, Krishnan Ravichandran, William J. Lambert, Harish K. Krishnamurthy, and Huong Do
- Subjects
010302 applied physics ,Materials science ,Comparator ,business.industry ,020208 electrical & electronic engineering ,Voltage divider ,Electrical engineering ,02 engineering and technology ,Voltage regulator ,Inductor ,01 natural sciences ,Magnetic core ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Cascode ,business ,Pulse-width modulation ,Voltage reference - Abstract
Fully Integrated Voltage Regulators (FIVR) with package-embedded air-core inductors [1] or on-die solenoid inductors with planar magnetic core [2] promise efficient power delivery and fine-grain wide-range DVFS in complex SoCs while providing fast transient response. The FIVR must provide high conversion efficiency across a wide operating range of output voltages and load currents, including light to medium loads, to maximize the overall energy efficiency of the SoC across different power states. Phase shedding and switch scaling have been used for high-frequency FIVR designs with pulse-width modulation (PWM) control in continuous conduction mode (CCM) to maintain high efficiency for large load currents [1–5], and pulse-frequency modulation (PFM) and hysteretic control have been used to achieve high efficiency across light to medium loads [3–5]. In this paper, we present an FIVR in 14nm CMOS with a 2.5nH air-core inductor embedded in an ultrathin coreless package $( 200 \mu m$ thick) (Fig. 8.5.7), featuring self-trimmed, soft-switched and digitally controlled variable ON-time DCM operation up to 70MHz to achieve high conversion efficiencies across light to medium load currents ranging from 5mA to 500mA and wide 0.7-1.2V output voltage range. The FIVR uses a cascoded thin-gate powertrain (Fig. 8.5.1) to support input voltages up to 2Vmax with the cascode bias rail set at $V_{in} /2$ which consumes $\lt/p\gt\lt1$ uA at light load. A small thick-gate device is connected across the inductor to dampen oscillations when the power stage is in a high-impedance state. The output voltage is monitored by a comparator with sub-ns response time which triggers an inductor current pulse when the output drops below the reference voltage. A resistor divider with a feedforward capacitor is used to achieve fast response time.
- Published
- 2019
178. Bacillus subtilis Hfq: A role in chemotaxis and motility
- Author
-
Chandrakant B. Jagtap, Pradeep Kumar, and K Krishnamurthy Rao
- Subjects
Factor Sigma-H ,0301 basic medicine ,Regulator ,Motility ,Sigma Factor ,Bacillus subtilis ,Host Factor 1 Protein ,Flagellum ,Hfq ,General Biochemistry, Genetics and Molecular Biology ,Microbiology ,03 medical and health sciences ,Cell Movement ,Sigma factor ,Family ,RNA, Messenger ,Rna Chaperone Hfq ,Function ,Regulation of gene expression ,Binding Protein Hfq ,Virulence ,biology ,Chemotaxis ,Translation (biology) ,Gene Expression Regulation, Bacterial ,Degu ,General Medicine ,biology.organism_classification ,Cell biology ,Bacillus Subtilis ,030104 developmental biology ,Genes ,General Agricultural and Biological Sciences ,Escherichia-Coli ,Tolerance ,Sm-Like Protein ,Regulation - Abstract
Hfq is a global post-transcriptional regulator that modulates the translation and stability of target mRNAs and thereby regulates pleiotropic functions, such as growth, stress, virulence and motility, in many Gram-negative bacteria. However, comparatively little is known about the regulation and function(s) of Hfq in Gram-positive bacteria. Recently, in Bacillus subtilis, a role for Hfq in stationary phase survival has been suggested, although the possibility of Hfq having an additional role(s) cannot be ruled out. In this study we show that an ortholog of Hfq in B. subtilis is regulated by the stress sigma factor, sigma(B), in addition to the stationary phase sigma factor, sigma(H). We further demonstrate that Hfq positively regulates the expression of flagellum and chemotaxis genes (fla/che) that control chemotaxis and motility, thus assigning a new function for Hfq in B. subtilis.
- Published
- 2016
179. Assessment of Topological Pattern of Urban Road Transport System of Calicut City
- Author
-
M.V.L.R. Anjaneyulu, M.G. Sreelekha, and K. Krishnamurthy
- Subjects
System development ,Geographic information system ,010504 meteorology & atmospheric sciences ,business.industry ,0211 other engineering and technologies ,Developing country ,02 engineering and technology ,Urban road ,01 natural sciences ,Transport engineering ,Urban planning ,Kilometer ,Environmental science ,business ,Transport system ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Network analysis - Abstract
A good road transport system can bring several benefits to a developing country since transportation is an engine for economic and social progress. The huge developmental cost of the transport system demands effective utilisation, which can be attained only when there is proper connectivity. Hence a great emphasis needs to be given to the layout and connectivity of the transport system. Urban road transport system has less theoretical research. Only some developed countries have performed urban transport system evaluation and hence it has great potential for development and application prospects. This study assessed the relationship between connectivity and development of the transport system of Calicut city using GIS. Road Network Development in kilometre per square kilometre varies from 1.20 to 16.53 with mean 5.99. Road development can be used as an indicator of urban development within a region, which in turn depends on the transport system connectivity. Based on this study it can be concluded that road transport system development is directly varying with transport system connectivity. This means that there is significant relationship between the level of road transport system connectivity and network development within the study area. On comparing the connectivity of the city as a whole with that of each of the zones, it is seen that the road transport system is not distributed in an even manner throughout the city. In fact the zones near the Central Business District have high connectivity and development, while the outer suburban zones have very less transport system development.
- Published
- 2016
- Full Text
- View/download PDF
180. Estimation of Value of Travel Time for Work Trips
- Author
-
M.V.L.R. Anjaneyulu, I.C. Athira, C.P. Muneera, and K. Krishnamurthy
- Subjects
050210 logistics & transportation ,education.field_of_study ,Labour economics ,05 social sciences ,Population ,Marginal rate of substitution ,010501 environmental sciences ,01 natural sciences ,Value of time ,Preference ,Willingness to pay ,Revealed preference ,0502 economics and business ,Value (economics) ,Econometrics ,Economics ,education ,Mode choice ,0105 earth and related environmental sciences - Abstract
Value of travel time (VOT) is one of the key inputs to travel demand models and is important for management and appraisal of transport investment decisions. The value of travel time can be defined as the price people are willing to pay to acquire an additional unit of time. Value of travel time has most often been determined by estimating mode choice models and evaluating marginal rate of substitution between the cost and travel time of the alternative modes. This study is aimed to find out the value of travel time associated with work trips of travellers within Calicut city. It refers to the concept of willingness to pay for reduction of travel time. Data were collected by means of combined revealed - stated preference survey on representative sample of population in Calicut city by work place interview. Stated preference experiment was designed to capture the responses for estimating VOT values for work trips. Responses in the form of “choice” among the presented choice alternatives were utilized to develop utility models and the estimated coefficients from the developed models were used to estimate VOT measures. The results indicate that the VOT associated with work trips is higher in high income groups. As income increases VOT also increases. Similarly, trip length also has a positive influence on VOT. As trip length increases, VOT increases. Within the same trip length itself, VOT varies among different income groups.
- Published
- 2016
181. Interaction between Road Network Connectivity and Spatial Pattern
- Author
-
M.V.L.R. Anjaneyulu, M.G. Sreelekha, and K. Krishnamurthy
- Subjects
Connectivity ,Orientation (computer vision) ,Spatial structure ,Road Network ,Transport network ,0211 other engineering and technologies ,Variance (land use) ,Poison control ,021107 urban & regional planning ,Fractal Dimension ,02 engineering and technology ,GIS ,Network connectivity ,Network Analysis ,Transport engineering ,Geography ,General Earth and Planetary Sciences ,Common spatial pattern ,021101 geological & geomatics engineering ,General Environmental Science ,Network analysis - Abstract
Road network is considered to be one of the keys to regional development of a region. The huge developmental cost of the road network demands effective utilisation, which can be attained only when there is proper connectivity and orientation. But the road network in many urban areas develop in an organic growth pattern. Hence a great emphasis needs to be given to the connectivity pattern of the road network. Urban road network has less theoretical research. Only some developed countries have carried out the evaluation of urban road network and hence it has great potential for development and application prospects. In this study an attempt has been made to analyse the road network connectivity and spatial pattern existing in Calicut city in India, and hence to determine if the network connectivity can explain significant variance in the spatial pattern of the network structure. Analysis reveals that transport network fractality is directly varying with respect to connectivity and coverage of the study area. Network density could better predict fractality of the road network than any other connectivity indicators. This means that there is significant relationship between the level of road network development and the network spatial structure within the study area.
- Published
- 2016
182. Physical and Optical Properties of PbO-Sb2O3-B2O3 Glasses Doped with Gd2O3
- Author
-
K. Krishnamurthy Goud, M. Chandra Shekhar Reddy, A. Prabhakar Reddy, and B. Appa Rao
- Subjects
010302 applied physics ,Diffraction ,Chemistry ,Doping ,Analytical chemistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,symbols.namesake ,Sphere packing ,Molar volume ,Differential scanning calorimetry ,Polarizability ,0103 physical sciences ,symbols ,Physics::Chemical Physics ,Absorption (chemistry) ,0210 nano-technology ,Lorentz force - Abstract
Glasses with the composition 30 PbO – 25 Sb2O3 – (45−x) B2O3 – x Gd2O3 were prepared by the melt-quenching method for x = 0 to 1 in steps of 0.2. The characterizationof the samples was done by X-ray diffraction and differential scanning calorimetric techniques. Various physical parameters such as density, molar volume, oxygen packing density etc. were evaluated. XRD,FTIR spectra, optical absorption at room temperature,differential scanning calorimetry have been investigated. The variations observed in all these properties due to different concentration of Gd2O3have been analyzed. Oxide ion polarizability of all the samples was calculated using Dimmitrov –Sakka relation. Optical basicity of all the samples was evaluated with the help of J.Duffy equation. Electronic polarizabilities were evaluatedfrom Lorentz -Lorentz equation.
- Published
- 2016
183. Efficiency of micro finance institution in India using data envelopment analysis
- Author
-
T. Sasikumar and K. Krishnamurthy
- Subjects
Microfinance ,Variable (computer science) ,Returns to scale ,law ,Rest (finance) ,Econometrics ,Data envelopment analysis ,Revenue ,Sample (statistics) ,Business ,Operating cost ,law.invention - Abstract
This paper investigates the efficiency of selected MFIs using Data Envelopment Analysis (DEA). DEA can aggregate the input-output components in such situations for obtaining an overall performance measures. The three inputs namely, number of personnel, physical assets of selected MFIs, operating costs and two outputs, viz, revenues and loans were considered to evaluate the relative efficiencies of MFIs of the sample set. It can be only 41.67% of MFIs were efficient under both model of DEA and rest of the units were inefficient. 58.33% of Sample MFIs were efficient under the Variable Return to Scale (VRS) model and 41.67% under the Constant Return to Scale (CRS). The RBI has since the mid 1990s helped in attracting funding for the sector by including microfinance in the “priority sector”, to which banks are mandated to allocate a percentage of their lending. However, no specific regulation was imposed on the sector as a whole primarily because it was felt that regulation may hamper the sector's key strengths of informality and flexibility. With minimal worker and reduced operating cost leads to reach efficient to BWDA, Grama vidiyal, SKS, Spanddana and Suryoday. Only 41.67% of MFIs were efficient under both model of DEA and rest of the units were inefficient. 58.33% of Sample MFIs were efficient under the Variable Return to Scale (VRS) model and 41.67% under the Constant Return to Scale (CRS).
- Published
- 2020
184. A Single-Stage, Single-Inductor, 6-Input 9-Output Multi-Modal Energy Harvesting Power Management IC for 100µW-120MW Battery-Powered IoT Edge Nodes
- Author
-
Kurian Dileep J, Sheldon Weng, Krishnan Ravichandran, Andrew Lines, Tanay Karnik, Vaibhav Vaidya, Christopher Schaef, James W. Tschanz, Kim Suhwan, Vivek De, Harish K. Krishnamurthy, and Xiaosen Liu
- Subjects
Power management ,Computer science ,business.industry ,Energy conversion efficiency ,Electrical engineering ,Energy consumption ,Inductor ,law.invention ,Power (physics) ,Capacitor ,law ,Transient response ,business ,Energy harvesting - Abstract
A 25MHz switching, event driven, 6-input and 9-output single inductor Energy-Harvesting PMIC (EHPMIC) with multi-modal harvesting capability from DC & AC sources delivers up to 120mW with a peak efficiency of 81.7% and only 120µW control power overhead. The high-frequency, high-bandwidth design optimally trades off EHPMIC conversion efficiency with inductor/capacitor size & transient response speed to enable the fast power state transitions demanded by the SoC in a compact IoT edge node, thus minimizing the overall platform size & energy consumption.
- Published
- 2018
185. EpsN from Bacillus subtilis 168 has UDP-2,6-dideoxy 2-acetamido 4-keto glucose aminotransferase activity in vitro
- Author
-
K. Krishnamurthy Rao, Chinmayi R. Kaundinya, Handanahal S. Savithri, and Petety V. Balaji
- Subjects
0301 basic medicine ,Bacillus subtilis ,medicine.disease_cause ,Biochemistry ,Uridine Diphosphate ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,Bacterial Proteins ,law ,medicine ,Gene ,Escherichia coli ,Pyridoxal ,Transaminases ,Schiff base ,biology ,Molecular Structure ,Mutagenesis ,Polysaccharides, Bacterial ,biology.organism_classification ,In vitro ,Recombinant Proteins ,carbohydrates (lipids) ,030104 developmental biology ,Glucose ,chemistry ,Recombinant DNA ,Biocatalysis ,Mutagenesis, Site-Directed - Abstract
The gene epsN of Bacillus subtilis 168 was cloned and overexpressed in Escherichia coli. Purified recombinant EpsN is shown to be a pyridoxal 5'-phosphate (PLP)-dependent aminotransferase by absorption spectroscopy, L-cycloserine inhibition and reverse phase HPLC studies. EpsN catalyzes the conversion of UDP-2,6-dideoxy 2-acetamido 4-keto glucose to UDP-2,6-dideoxy 2-acetamido 4-amino glucose. Lys190 was found by sequence comparison and site-directed mutagenesis to form Schiff base with PLP. Mutagenesis studies showed that, in addition to Lys190, Ser185, Glu164, Gly58 and Thr59 are essential for aminotransferase activity.
- Published
- 2018
186. In vitro characterization of N-terminal truncated EpsC from Bacillus subtilis 168, a UDP-N-acetylglucosamine 4,6-dehydratase
- Author
-
K. Krishnamurthy Rao, Chinmayi R. Kaundinya, Handanahal S. Savithri, and Petety V. Balaji
- Subjects
0301 basic medicine ,BIOCHEMICAL-CHARACTERIZATION ,Operon ,NAD(+) dependent UDP-GlcNAc 4,6-dehydratase ,PROTEIN ,Bacillus subtilis ,CAMPYLOBACTER ,Biochemistry ,Substrate Specificity ,chemistry.chemical_compound ,FUNCTIONAL-CHARACTERIZATION ,Nucleotide ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,biology ,Nucleoside Diphosphate Sugars ,PSEUDAMINIC ACID ,Recombinant Proteins ,Transmembrane domain ,Acetyltransferase ,GLCNAC ,Sequence analysis ,Biophysics ,03 medical and health sciences ,Biosynthesis ,Bacterial Proteins ,Protein Domains ,Surface plasmon resonance ,Escherichia coli ,BIOSYNTHESIS ,DIAMINO SUGAR ,Molecular Biology ,Hydro-Lyases ,Enzyme Assays ,STAPHYLOCOCCUS-AUREUS ,N,N ' - diacetylbacillosamine biosynthetic ,030102 biochemistry & molecular biology ,PSEUDOMONAS-AERUGINOSA ,UDP-keto sugars ,biology.organism_classification ,Peptide Fragments ,carbohydrates (lipids) ,pathway enzyme ,Kinetics ,030104 developmental biology ,chemistry ,Dehydratase ,Mutation - Abstract
Bacillus subtilis 168 EpsC is annotated as “Probable polysaccharide biosynthesis protein” in the SwissProt database. epsC is part of the eps operon, thought to be involved in the biosynthesis of exopolymeric substances (EPS). The present study was undertaken to determine the molecular function of EpsC. Sequence analysis of EpsC suggested the presence of a transmembrane domain. Two N-terminal deletion mutants in which residues 1–89 (EpsC89) and 1–115 (EpsC115) are deleted were cloned and overexpressed. Enzyme activity and substrate preferences were investigated by reverse phase HPLC, surface plasmon resonance (SPR) spectroscopy and absorption spectroscopy. These data show that EpsC has UDP-GlcNAc 4,6-dehydratase activity in vitro. Purified recombinant proteins were found to utilise UDP-Glc and TDP-Glc also as substrates. In addition, EpsC115 could utilise UDP-Gal and UDP-GalNAc as substrates whereas EpsC89 could only bind these two sugar nucleotides. These results show that deletion of a longer N-terminal region broadens substrate specificity. These broadened specificity is perhaps an outcome of the deletion of the putative transmembrane domain and may not be present in vivo. EpsC, together with the aminotransferase EpsN (Kaundinya CR et al., Glycobiology, 2018) and acetyltransferase EpsM (unpublished data), appears to be involved in the biosynthesis of N,N′-diacetylbacillosamine.
- Published
- 2018
187. The Role of Proteoglycans and Glycosaminoglycans in Heart Valve Biomechanics
- Author
-
Varun K. Krishnamurthy and K. Jane Grande-Allen
- Subjects
carbohydrates (lipids) ,Extracellular matrix ,Glycosaminoglycan ,Future studies ,medicine.anatomical_structure ,Tissue engineering ,Tissue biomechanics ,Biomechanics ,medicine ,Heart valve ,Biology ,Valve disease ,Cell biology - Abstract
Proteoglycans (PGs) and glycosaminoglycans (GAGs) have long been recognized as constituents of heart valves but their precise functions have been mysterious and underrepresented. The heterogeneity, dynamic processing and viscoelastic nature of PGs and GAGs, and their ability to exist independently or in association with other extracellular matrix (ECM) components, contribute to the overall complexity of valve ECM (structure), and impact local tissue biomechanics (function). This chapter will discuss various approaches for elucidating the biomechanical properties of valvular PGs and GAGs, will relate valve tissue hemodynamic alterations and valve cell biomechanical stimuli to differences in PG/GAG expression (and misexpression), and will address directions for future studies.
- Published
- 2018
188. Re-defining flow in construction process for facilitating the identification and quantification of generic overruns existing in construction industry today
- Author
-
Ali, Safeer Ali Abbas, primary, C, Arun, additional, and K, Krishnamurthy, additional
- Published
- 2018
- Full Text
- View/download PDF
189. Review of Molecular and Mechanical Interactions in the Aortic Valve and Aorta: Implications for the Shared Pathogenesis of Aortic Valve Disease and Aortopathy
- Author
-
Daria A. Narmoneva, Robert B. Hinton, J. Michael Smith, Richard C Godby, G. R. Liu, Loren F. Hiratzka, and Varun K. Krishnamurthy
- Subjects
Heart Defects, Congenital ,Models, Molecular ,Aortic valve ,medicine.medical_specialty ,Organogenesis ,Aortic Diseases ,Biophysics ,Heart Valve Diseases ,Pharmaceutical Science ,Translational research ,Disease ,Biology ,Pathogenesis ,Bicuspid Aortic Valve Disease ,Internal medicine ,medicine.artery ,Genetics ,medicine ,Genetic predisposition ,Humans ,Thoracic aorta ,Aorta ,Genetics (clinical) ,Tissue homeostasis ,Ventricular Remodeling ,Models, Theoretical ,Elastic Tissue ,medicine.anatomical_structure ,Aortic Valve ,Cardiology ,Molecular Medicine ,Proteoglycans ,Cardiology and Cardiovascular Medicine - Abstract
Aortic valve disease (AVD) and aortopathy are associated with substantial morbidity and mortality, representing a significant cardiovascular healthcare burden worldwide. These mechanobiological structures are morphogenetically related and function in unison from embryonic development through mature adult tissue homeostasis, serving both coordinated and distinct roles. In addition to sharing common developmental origins, diseases of the aortic valve and proximal thoracic aorta often present together clinically. Current research efforts are focused on identifying etiologic factors and elucidating pathogenesis, including genetic predisposition, maladaptive cell-matrix remodeling processes, and hemodynamic and biomechanical perturbations. Here, we review the impact of these processes as they pertain to translational research efforts, emphasizing the overlapping relationship of these two disease processes. The successful application of new therapeutic strategies and novel tissue bioprostheses for AVD and/or aortopathy will require an understanding and integration of molecular and biomechanical processes for both diseases.
- Published
- 2014
190. A digitally controlled linear regulator for per-core wide-range DVFS of atom™ cores in 14nm tri-gate CMOS featuring non-linear control, adaptive gain and code roaming
- Author
-
Am Dhanashekar, Harish K. Krishnamurthy, Tarun Mahajan, Ramnarayanan Muthukaruppan, Sumedha Mangal, Rupak Ghayal, and Vivek De
- Subjects
Engineering ,business.industry ,Settling time ,020208 electrical & electronic engineering ,Transistor ,Linear regulator ,Hardware_PERFORMANCEANDRELIABILITY ,02 engineering and technology ,Nonlinear control ,020202 computer hardware & architecture ,law.invention ,CMOS ,law ,Logic gate ,Hardware_INTEGRATEDCIRCUITS ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Voltage droop ,Digital control ,business - Abstract
A digitally controlled LDO in 14nm tri-gate CMOS powering an Atom™ core with embedded power gates enables per-core DVFS over a wide voltage-frequency range. The LDO demonstrates 99.6% peak current efficiency at 2.5A load current and provides a power density of 26.1 W/mm2. The multi-mode digital controller featuring non-linear mode and adaptive gain achieves
- Published
- 2017
191. Comparison of Glottic Exposure and Haemodynamic Response Using Macintosh and Flexitip Blades in Adult
- Author
-
Noorudheen Karuvambil and T. K. Krishnamurthy
- Subjects
medicine.medical_specialty ,animal structures ,medicine.diagnostic_test ,business.industry ,Haemodynamic response ,medicine.medical_treatment ,Laryngoscopy ,food and beverages ,Endotracheal intubation ,Surgery ,stomatognathic system ,Anesthesia ,Medicine ,Intubation ,business - Abstract
Laryngoscopy forms an important part of general anesthesia and endotracheal intubation. To ease the process of intubation laryngoscopic blades of different shapes have been designed. The aim of this study is to evaluate the laryngoscopic view and haemodynamic response using conventional Macintosh blade and is compared with that obtained using Flexitip blade.
- Published
- 2017
192. Digitally controlled voltage regulator using oscillator-based ADC with fast-transient-response and wide dropout range in 14nm CMOS
- Author
-
Ramnarayanan Muthukaruppan, Dheeraj M. Shetty, Sumedha Mangal, Harish K. Krishnamurthy, and Tarun Mahajan
- Subjects
Engineering ,CMOS ,Dropout voltage ,business.industry ,Load regulation ,Dropout (communications) ,Electronic engineering ,Voltage droop ,Voltage regulator ,Transient response ,business ,Voltage - Abstract
In this paper, we propose a digitally controlled voltage regulator with fast-transient-response using an oscillator based ADC implemented in 14nm CMOS technology. The transient response is critical to mitigate droop for large di/dt seen in cores and wide dropout range helps enable DVFS to improve power/performance ratio. In this work, we target 1-1.15V input voltage with output voltage range of 0.5–1.12 V with minimum 30mV dropout, and load current range of >22× with 0.1A–2.2A at 50mV dropout with
- Published
- 2017
193. 20.1 A digitally controlled fully integrated voltage regulator with on-die solenoid inductor with planar magnetic core in 14nm tri-gate CMOS
- Author
-
Pavan Kumar, James W. Tschanz, Vivek De, Rinkle Jain, Harish K. Krishnamurthy, George E. Matthew, Krishnan Ravichandran, Sheldon Weng, Vaibhav Vaidya, and Stephen Kim
- Subjects
010302 applied physics ,Engineering ,business.industry ,Electrical engineering ,Solenoid ,Hardware_PERFORMANCEANDRELIABILITY ,Voltage regulator ,Inductor ,01 natural sciences ,Die (integrated circuit) ,Power (physics) ,Magnetic core ,CMOS ,0103 physical sciences ,Electronic engineering ,Transient response ,business - Abstract
Fully integrated on-die buck voltage regulators (VR) promise efficient and wide-range local power delivery and management capability with fast transient response for fine-grain DVFS domains of high power density in complex SoCs. Integration of high-quality power inductors that can support high current density with minimal losses is a major challenge.
- Published
- 2017
194. Rv3634c from Mycobacterium tuberculosis H37Rv encodes an enzyme with UDP-Gal/Glc and UDP-GalNAc 4-epimerase activities
- Author
-
K. Krishnamurthy Rao, Peehu Pardeshi, and Petety V. Balaji
- Subjects
Protein Structure Comparison ,Glycerol ,0301 basic medicine ,Protein Conformation ,Mutant ,lcsh:Medicine ,Nucleotide sugar ,Biochemistry ,Database and Informatics Methods ,UDPglucose 4-Epimerase ,chemistry.chemical_compound ,Macromolecular Structure Analysis ,Cloning, Molecular ,lcsh:Science ,Peptide sequence ,Liquid Chromatography ,chemistry.chemical_classification ,Multidisciplinary ,Biochemical-Characterization ,Chromatographic Techniques ,Genomics ,Galactose 4'-Epimerase ,Recombinant Proteins ,Cell-Wall ,Actinobacteria ,Physical sciences ,Chemistry ,Mycobacterium-Tuberculosis ,Sequence Analysis ,Research Article ,Protein Structure ,Bioinformatics ,030106 microbiology ,Substrate-Specificity ,Pseudomonas-Aeruginosa ,Monomers (Chemistry) ,Biology ,Research and Analysis Methods ,Campylobacter jejuni ,Escherichia-Coli O86-B7 ,03 medical and health sciences ,Sequence Motif Analysis ,Catalytic triad ,Humans ,Point Mutation ,Tuberculosis ,Polymer chemistry ,Amino Acid Sequence ,Molecular Biology ,Bacteria ,Hexose 4-Epimerases ,lcsh:R ,Organisms ,Campylobacter-Jejuni ,Biology and Life Sciences ,Proteins ,Mycobacterium tuberculosis ,biology.organism_classification ,High Performance Liquid Chromatography ,Enzyme assay ,carbohydrates (lipids) ,030104 developmental biology ,Enzyme ,chemistry ,Mutagenesis, Site-Directed ,biology.protein ,Glcnac/Glc 4-Epimerase ,lcsh:Q ,NAD+ kinase ,Carbohydrate Epimerases ,Sequence Alignment - Abstract
A bioinformatics study revealed that Mycobacterium tuberculosis H37Rv (Mtb) contains sequence homologs of Campylobacter jejuni protein glycosylation enzymes. The ORF Rv3634c from Mtb was identified as a sequence homolog of C. jejuni UDP-Gal/GalNAc 4-epimerase. This study reports the cloning of Rv3634c and its expression as an N-terminal His-tagged protein. The recombinant protein was shown to have UDP-Gal/Glc 4-epimerase activity by GOD-POD assay and by reverse phase HPLC. This enzyme was shown to have UDP-GalNAc 4-epimerase activity also. Residues Ser121, Tyr146 and Lys150 were shown by site-directed mutagenesis to be important for enzyme activity. Mutation of Ser121 and Tyr146 to Ala and Phe, respectively, led to complete loss of activity whereas mutation of Lys150 to Arg led to partial loss of activity. There were no gross changes in the secondary structures of any of these three mutants. These results suggest that Ser121 and Tyr146 are essential for epimerase activity of Rv3634c. UDP-Gal/Glc 4-epimerases from other organisms also have a catalytic triad consisting of Ser, Tyr and Lys. The triad carries out proton transfer from nucleotide sugar to NAD(+) and back, thus effecting the epimerization of the substrate. Addition of NAD(+) to Lys150 significantly abrogates the loss of activity, suggesting that, as in other epimerases, NAD(+) is associated with Rv3634c.
- Published
- 2017
195. A dps promoter based expression system for improved solubility of expressed proteins in Escherichia coli
- Author
-
Piyush Sethia, K. Krishnamurthy Rao, and Santosh Noronha
- Subjects
Protein Solubility ,Cytoplasm ,Cost effectiveness ,Biomedical Engineering ,lac operon ,Heterologous ,Bioengineering ,Dps Promoter ,Cloned Genes ,Growth ,Biology ,medicine.disease_cause ,Dna-Binding Protein ,Applied Microbiology and Biotechnology ,law.invention ,law ,medicine ,Stationary-Phase ,E.-Coli ,Escherichia coli ,Recombinant Protein Expression ,Escherichia Coli ,Improved solubility ,Molecular biology ,Heterologous Gene ,Biochemistry ,Metabolic Load ,Rna-Polymerase ,Recombinant DNA ,Soluble Recombinant Proteins ,Industrial and production engineering ,mCherry ,Biotechnology - Abstract
Escherichia coli is widely used for recombinant protein production due to its well established genetic manipulation techniques and cost effectiveness of the associated production processes. Soluble expression of heterologous recombinant proteins constitutes a major problem in the deployment of bacterial expression systems. We have developed a dps promoter based expression system in E. coli for improved solubility of expressed proteins. The resulting expression system was found to be superior to the IPTG inducible T7 promoter based pET expression system for production of soluble beta-galactosidase, tdTomato, and mCherry. The dps promoter based expression system was shown to be functional in most commonly used strains of E. coli without need for prior genetic manipulation of the host genome.
- Published
- 2014
196. Asymmetric Cell–Matrix and Biomechanical Abnormalities in Elastin Insufficiency Induced Aortopathy
- Author
-
Daria A. Narmoneva, Stefanie V. Biechler, Janaka Wansapura, Robert B. Hinton, Hanna Osinska, Ashlie N. Evans, Varun K. Krishnamurthy, Kelsey Maddy, and Richard L. Goodwin
- Subjects
Aging ,Pathology ,medicine.medical_specialty ,Vascular smooth muscle ,Myocytes, Smooth Muscle ,Aortic Diseases ,Biomedical Engineering ,Mice, Transgenic ,Extracellular matrix ,Elastic Modulus ,medicine.artery ,Ascending aorta ,medicine ,Animals ,Humans ,Thoracic aorta ,Child ,Aorta ,biology ,Chemistry ,Biglycan ,Anatomy ,Biomechanical Phenomena ,Elastin ,medicine.anatomical_structure ,Neural Crest ,cardiovascular system ,biology.protein ,Proteoglycans ,Elastic fiber - Abstract
Aortopathy is characterized by vascular smooth muscle cell (VSMC) abnormalities and elastic fiber fragmentation. Elastin insufficient (Eln +/− ) mice demonstrate latent aortopathy similar to human disease. We hypothesized that aortopathy manifests primarily in the aorto-pulmonary septal (APS) side of the thoracic aorta due to asymmetric cardiac neural crest (CNC) distribution. Anatomic (aortic root vs. ascending aorta) and molecular (APS vs. non-APS) regions of proximal aorta tissue were examined in adult and aged wild type (WT) and mutant (Eln +/− ) mice. CNC, VSMCs, elastic fiber architecture, proteoglycan expression, morphometrics and biomechanical properties were examined using histology, 3D reconstruction, micropipette aspiration and in vivo magnetic resonance imaging (MRI). In the APS side of Eln +/− aorta, Sonic Hedgehog (SHH) is decreased while SM22 is increased. Elastic fiber architecture abnormalities are present in the Eln +/− aortic root and APS ascending aorta, and biglycan is increased in the aortic root while aggrecan is increased in the APS aorta. The Eln +/− ascending aorta is stiffer than the aortic root, the APS side is thicker and stiffer than the non-APS side, and significant differences in the individual aortic root sinuses are observed. Asymmetric structure–function abnormalities implicate regional CNC dysregulation in the development and progression of aortopathy.
- Published
- 2014
197. Hybrid ILC Strategy for Magnetic Ball Suspension System
- Author
-
sup>P.K. Bhaba, sup>K. Krishnamurthy, sup>S. Somasundaram, and S. Sathiyavathi
- Subjects
Engineering ,Set point tracking ,General Computer Science ,Control theory ,business.industry ,Iterative learning control ,General Engineering ,Ball (bearing) ,Control reconfiguration ,PID controller ,Control engineering ,business - Abstract
Controlling of magnetic ball suspension system using hybrid Iterative Learning Controller (ILC) is investigated in this study. Hybrid ILC modifies the control input for the next iteration by learning from the present input and the errors of previous iteration without reconfiguration of the existing Proportional, Integral and Derivative (PID) controller. Firstly, hybrid ILC is employed to stabilize the ball and then set point tracking is performed to evaluate the efficacy of the controller. The effectiveness of designed hybrid ILC is analyzed based on performance indices via simulation.
- Published
- 2014
198. A Framework for Estimating Driver Decisions Near Intersections
- Author
-
Ashok K. Krishnamurthy, Umit Ozguner, and Vijay Gadepally
- Subjects
Engineering ,Mathematical model ,business.industry ,Estimation theory ,Intersection (set theory) ,Mechanical Engineering ,Real-time computing ,Markov process ,Control engineering ,Mobile robot ,Computer Science Applications ,Vehicle dynamics ,symbols.namesake ,Automotive Engineering ,symbols ,business ,Hidden Markov model ,Intelligent transportation system - Abstract
We present a framework for the estimation of driver behavior at intersections, with applications to autonomous driving and vehicle safety. The framework is based on modeling the driver behavior and vehicle dynamics as a hybrid-state system (HSS), with driver decisions being modeled as a discrete-state system and the vehicle dynamics modeled as a continuous-state system. The proposed estimation method uses observable parameters to track the instantaneous continuous state and estimates the most likely behavior of a driver given these observations. This paper describes a framework that encompasses the hybrid structure of vehicle-driver coupling and uses hidden Markov models (HMMs) to estimate driver behavior from filtered continuous observations. Such a method is suitable for scenarios that involve unknown decisions of other vehicles, such as lane changes or intersection access. Such a framework requires extensive data collection, and the authors describe the procedure used in collecting and analyzing vehicle driving data. For illustration, the proposed hybrid architecture and driver behavior estimation techniques are trained and tested near intersections with exemplary results provided. Comparison is made between the proposed framework, simple classifiers, and naturalistic driver estimation. Obtained results show promise for using the HSS-HMM framework.
- Published
- 2014
199. Research updates on graphene oxide-based polymeric nanocomposites
- Author
-
Rathanasamy Rajasekar, P. Sathishkumar, Sumanta Sahoo, K. Krishnamurthy, K.V. Maheshkumar, E. Uddin, and Samir Kumar Pal
- Subjects
chemistry.chemical_classification ,Supercapacitor ,Nanocomposite ,Materials science ,Polymers and Plastics ,Graphene ,Oxide ,General Chemistry ,Polymer ,Exfoliation joint ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Materials Chemistry ,Ceramics and Composites ,Graphite ,Composite material ,Graphene oxide paper - Abstract
Graphene oxide (GO) is a carbon-based material, which is one atom thick sheet of graphite. The nanofillers have exceptional stiffness and strength owing to the presence of two-dimensional graphene backbone. Especially owing to this reason, nanocomposites have been developed using GO for several applications. This review article explores the synthesis of GO from flake graphite. Main emphasis has been afforded on the preparation and characterization of GO nanocomposites, utilizing various industrial polymers for wide application in aerospace, biomedical, military, supercapacitors, electrical, sensor, and so on. Morphological characterization exploring the interaction and extent of dispersion of GO nanosheets in the polymer matrices is extensively accounted. From the reports, it is clear that exfoliation and strong interaction of GO tremendously improved the physical, mechanical, thermal, electrochemical, biocompatibility, and tribological properties of the added polymer. POLYM. COMPOS., 35:2297–2310, 2014. © 2014 Society of Plastics Engineers
- Published
- 2014
200. Study of cognitive functions in breast cancer patients: A case control study
- Author
-
Anupama Zeena Sequeira and K Krishnamurthy
- Subjects
cognition ,lcsh:RT1-120 ,medicine.medical_specialty ,Activities of daily living ,lcsh:Nursing ,business.industry ,Case-control study ,Cancer ,lcsh:RX1-681 ,Cognition ,Context (language use) ,medicine.disease ,Breast cancer ,Quality of life ,lcsh:Homeopathy ,medicine ,Physical therapy ,Outpatient clinic ,cancer ,business - Abstract
Context: One-third of breast cancer survivors report difficulties with concentration, multi-tasking, and memory. Cognitive dysfunction can have an impact on quality of life by affecting activities of daily living, treatment compliance, interpersonal relationships, work/profession, and future. Aims: The objective of this study was to evaluate the cognitive functions in breast cancer patients. Settings and Design: This study was conducted in the outpatient department of Oncology from where the cases were recruited. The controls were patients attending other departments and not suffering from cancer. Materials and Methods: A total of 60 patients, 30 breast cancer patients and 30 non-cancer individuals patients matched for age, education were evaluated. Tools used were SMMSE, TMT-B, and DSST for evaluation of cognitive functions. Statistical Analysis: The various findings were analyzed using Chi-square test, Mann-Whitney Test, T test and ANOVA. Results: Breast cancer patients had highly statistically significant cognitive deficits in language and recall domains and significant deficit on orientation domain of SMMSE. They performed poorly in TMT-B, taking more time to complete the test which was statistically highly significant. No significant deficits were noted on the DSST test. Conclusion: Breast cancer patients show statistically significant cognitive deficits as compared to non cancer individuals.
- Published
- 2014
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.