Design and Analysis of a Mechanical Driveline with Generator for an Atmospheric Energy Harvester

The advent of renewable energy as a primary power source for microelectronic devices has motivated research within the energy harvesting community over the past decade. Compact, self-contained, portable energy harvesters can be applied to wireless sensor networks, Internet of Things (IoT) smart appliances, and a multitude of standalone equipment; replacing batteries and improving the operational life of such systems. Atmospheric changes influenced by cyclical temporal variations offer an abundance of harvestable thermal energy. However, the low conversion efficiency of a common thermoelectric device does not tend to be practical for microcircuit operations. One solution may lie in a novel electromechanical power transformer integrated with a thermodynamic based phase change material to create a temperature/pressure energy harvester. The performance of the proposed harvester will be investigated using both numerical and experimental techniques to offer insight into its functionality and power generation capabilities. The atmospheric energy harvester consists of a ethyl chloride filled mechanical bellows attached to an end plate and constrained by a stiff spring and four guide rails that allow translational motion. The electromechanical power transformer consists of a compound gear train driven by the bellows end plate, a ratchet-controlled coil spring to store energy, and a DC micro generator. Nonlinear mathematical models have been developed for this multi-domain dynamic system using fundamental engineering principles. The initial analyses predicted 9.6 mW electric power generation over a 24 hour period for ±1°C temperature variations about a nominal 22°C temperature. Transfer functions were identified from the lumped parameter models and the transient behavior of the coupled thermal-electromechanical system has been studied. A prototype experimental system was fabricated and laboratory tested to study the overall performance and validate the mathematical models for the integrated energy harvester system. The experimental results agree with the numerical analyses in behavioral characteristics. Further, the power generation capacity of 30 mW for a representative electrical resistance load and emulated rack input which correspond to 50 cyclic bidirectional temperature variations (~175 hours of field operation) validated the simulation models. This research study provides insight into the challenges of designing an electromechanical power transformer to complement an atmospheric energy harvester system. The mathematical models estimated the behavior and performance of the integrated harvester system and establishes a foundation for future optimization studies. The opportunity to power microelectronic devices in the milliwatt range for burst electric operation or with the use of supercapacitors/batteries enables global remote operation of smart appliances. This system can assist in reducing/eliminating the need for batteries and improving the operational life of a variety of autonomous equipment. Future research areas have been identified to improve the overall system capabilities and implement the harvester device for real-world applications

DOES PROVIDING FREE ANTI-RETROVIRAL THERAPY ENSURE OPTIMAL ADHERENCE AMONG PEOPLE LIVING WITH HIV / AIDS?

AbstractIntroduction/Back ground: Availability of Anti-Retroviral Therapy (ART) has revolutionalised the management of Human Immunodeficiency Virus /Acquired Immuno Deficiency Syndrome (HIV/AIDS) and improved the survival of those infected with the virus. However, adherence to therapy is a prerequisite for treatment success and preventing drug resistance. Aim: The present study was carried out with the aim of determining the level of adherence and factors affecting it among patients receiving free ART. Methods: A cross sectional study design was adopted and 320 HIV positive patients receiving free ART from a district hospital in Udupi were interviewed using a semi-structured questionnaire. Adherence to ART >95% of the prescribed medication was used as the cut off for deciding on the treatment adherence. Results: An encouragingly high 96.9% of the individuals were adherent to the medication over the past month. However, 41.8% of the participants reported to have ever missed doses of ART. On univariate analysis, having ever consumed alcohol, absence of side effects such as fatigue and tingling/numbness, having a feeling of sadness and sleep disturbances, being on Efavirenz based regimen, non-disclosure HIV status, being unsure of continuing lifelong treatment were significantly associated with non-adherence (p<0.05).Conclusion: Although non adherence was of concern among a small proportion of participants, a large number of them reported to have ever missed doses of ART.  This finding suggests that adherence rate may be lower over longer periods of time. Hence, periodic assessments may address patient specific barriers and help to improve the adherence rate among this population.Â

XRCC2 Regulates Replication Fork Progression during dNTP Alterations

RAD51 paralogs are essential for maintenance of genomic integrity through protection of stalled replication forks and homology-directed repair (HDR) of double-strand breaks. Here, we find that a subset of RAD51 paralogs, XRCC2 (FANCU) and its binding partner RAD51D, restrain active DNA synthesis during dinucleotide triphosphate (dNTP) alterations in a manner independent of HDR. The absence of XRCC2 is associated with increased levels of RRM2, the regulatory subunit of ribonucleotide reductase (RNR), and concomitantly high nucleotide pools, leading to unrestrained fork progression and accumulation of DNA damage during dNTP alterations. Mechanistically, this function is independent of redox signaling and RAD51-mediated fork reversal and is regulated by ataxia-telangiectasia and Rad3-related (ATR) signaling through phosphorylation of XRCC2 (Ser247). Together, these findings identify roles of RAD51 paralogs in the control of replication fork progression and maintenance of genome stability during nucleotide pool alterations

Comparison between ocular biometry parameters in patients with unilateral congenital glaucoma

Purpose: To compare the axial length (AL) and corneal diameter between glaucomatous eye (GE) and fellow normal eye (NE) in patients with unilateral congenital glaucoma and to obtain a normative database for ocular growth among Indian children below 3 years of age. Methods: Retrospective longitudinal study. Patients who had a follow-up of 3 years from diagnosis with ocular biometry parameters being recorded at least thrice (once a year) and fellow eye being normal were included. Data collected were age, gender, intraocular pressure (IOP), AL, corneal diameter, optic disc findings, diagnosis, and surgery details. Results: Eleven patients were analyzed. All GE underwent combined trabeculotomy with trabeculectomy. Mean (SD) baseline IOP, AL, and corneal diameter were 17.1 (6.7) mmHg, 18.9 (1.1) mm and 12 (0.91) mm in GE, and 11.1 (3.8) mmHg, 17.8 (0.44) mm, and 10.5 (0.58) mm in NE, respectively. Increase in AL was 3.1 mm in the first year followed by 0.6 mm in second year and 0.4 mm in third year in GE compared to 2.6, 0.6, and 0.5 mm in NE, respectively. Corneal diameter increased by 1.1 mm in GE in the first year and remained stable thereafter compared to 0.7 mm in first year followed by 0.3 mm in second year and stable thereafter in NE. The percentage of success was 73% at 3 years. Conclusion: Axial length and corneal diameter were higher in GE than NE at all-time points. With prompt intervention, the growth curve of the GE was made parallel to that of NE

RAD51C/XRCC3 Facilitates Mitochondrial DNA Replication and Maintains Integrity of the Mitochondrial Genome

Mechanisms underlying mitochondrial genome maintenance have recently gained wide attention, as mutations in mitochondrial DNA (mtDNA) lead to inherited muscular and neurological diseases, which are linked to aging and cancer. It was previously reported that human RAD51, RAD51C, and XRCC3 localize to mitochondria upon oxidative stress and are required for the maintenance of mtDNA stability. Since RAD51 and RAD51 paralogs are spontaneously imported into mitochondria, their precise role in mtDNA maintenance under unperturbed conditions remains elusive. Here, we show that RAD51C/XRCC3 is an additional component of the mitochondrial nucleoid having nucleus-independent roles in mtDNA maintenance. RAD51C/XRCC3 localizes to the mtDNA regulatory regions in the D-loop along with the mitochondrial polymerase POLG, and this recruitment is dependent upon Twinkle helicase. Moreover, upon replication stress, RAD51C and XRCC3 are further enriched at the mtDNA mutation hot spot region D310. Notably, the absence of RAD51C/XRCC3 affects the stability of POLG on mtDNA. As a consequence, RAD51C/XRCC3-deficient cells exhibit reduced mtDNA synthesis and increased lesions in the mitochondrial genome, leading to overall unhealthy mitochondria. Together, these findings lead to the proposal of a mechanism for a direct role of RAD51C/XRCC3 in maintaining mtDNA integrity under replication stress conditions

ATR Signaling Uncouples the Role of RAD51 Paralogs in Homologous Recombination and Replication Stress Response

ATR kinase-mediated replication checkpoint is vital for genome maintenance following replication stress. Previously, we showed that XRCC2-RAD51D (DX2) sub-complex of RAD51 paralogs restrains active DNA synthesis during dNTP alterations, in a manner dependent on ATR-mediated phosphorylation of XRCC2. Here, we find that unrestrained fork progression in XRCC2 deficiency and phosphorylation defect causes replication-associated errors, subsequently resulting in genome-wide double-strand breaks (DSBs) and early activation of ATM signaling. Cells defective in XRCC2 phosphorylation exhibit ATM/ATR-mediated early activation of XRCC3 during perturbed replication, which facilitates recombination-mediated repair of the post-replicative DNA damage and thereby promotes cell viability. Collectively, our findings identify collaborative roles of RAD51 paralog complexes during replication stress and reveal their differential regulation by ATR signaling to promote cell survival and genome integrity

Effect of solvents on total phenolics, antioxidant and antimicrobial properties of <i style="mso-bidi-font-style:normal">Bridelia retusa</i> Spreng. stem bark

442-447Effect of different solvents such as water, ethanol (50%), methanol (50%) and acetone (70%) on the total polyphenol content, antioxidant and antimicrobial activities of stem bark of B. <i style="mso-bidi-font-style: normal">retusa Spreng. was studied. Phenolic content of extracts were determined using Folin-Ciocalteu assays and antioxidant activity was carried out by DPPH and reducing power assay. The results showed that different solvent with different polarity possess significant effect on polyphenolic contents and antioxidant activity. Acetone extract shown highest polyphenol content, 4.7-7.6 mg equivalent to Gallic acid. It also has shown highest antioxidant activity. MIC value &lt;5mg/ml indicated that stem bark of this plant is a potential natural antimicrobial agent