Influence of dissipation on extreme oscillations of a forced anharmonic oscillator

Dynamics of a periodically forced anharmonic oscillator (AO) with cubic nonlinearity, linear damping, and nonlinear damping, is studied. To begin with, the authors examine the dynamics of an AO. Due to this symmetric nature, the system has two neutrally stable elliptic equilibrium points in positive and negative potential-wells. Hence, the unforced system can exhibit both single-well and double-well periodic oscillations depending on the initial conditions. Next, the authors include nonlinear damping into the system. Then, the symmetry of the system is broken instantly and the stability of the two elliptic points is altered to result in stable focus and unstable focus in the positive and negative potential-wells, respectively. Consequently, the system is dual-natured and is either non-dissipative or dissipative, depending on location in the phase space. Furthermore, when one includes a periodic external forcing with suitable parameter values into the nonlinearly damped AO system and starts to increase the damping strength, the symmetry of the system is not broken right away, but it occurs after the damping reaches a threshold value. As a result, the system undergoes a transition from double-well chaotic oscillations to single-well chaos mediated through extreme events (EEs). Furthermore, it is found that the large-amplitude oscillations developed in the system are completely eliminated if one incorporates linear damping into the system. The numerically calculated results are in good agreement with the theoretically obtained results on the basis of Melnikov's function. Further, it is demonstrated that when one includes linear damping into the system, this system has a dissipative nature throughout the entire phase space of the system. This is believed to be the key to the elimination of EEs.Comment: 15 pages, 9 figures. Accepted for publications in International Journal of Non-Linear Mechanic

ANTIFOULING EFFECTS OF GRACILARIA EDULIS TO SCREEN THE BIOCHEMICAL AND CYTOTOXICITY ASSAY IN MALLIPATTINAM HARBOUR

Ship operators have faced the problem of biofouling, or the adhesion and growth of organisms on submerged, man-made surfaces, for at least two millennia. Barnacles and other sessile marine invertebrates contribute to biofouling, which raises the frictional resistance of a ship's hull and increases the power and fuel needed to maintain speed. More than a century ago, scientists and engineers realized that a deeper understanding of the biology of the organisms involved particularly with regard to larval settlement and metamorphosis as well as adhesives and adhesion would be necessary to solve the biofouling problem. Using barnacles has been a valuable tool for this research. One strategy for studying innovative non-toxic anti-fouling materials used in this study is to take advantage of some marine organisms' intrinsic ability to manufacture chemical defense compounds in order to maintain an epibiont-free surface. In this study Gracilaria edulis was intensely analyzed for its biochemical constituents like protein and lipid content along with the cytotoxicity analysis. These newly developed materials can be helpful probes to further our understanding of these processes, even though basic research on topics like the nature of the interaction between organismal adhesives and the substrate or the ability of settling larvae to perceive surface cues has not had a significant impact on the development of most current biofouling control technologies

Study on drug profile used in common pregnancy influenced issues and its complications

Background: Pregnancy influenced issues are common among pregnant women treated by medications that causes complication in mother and fetus. The study aims to identify patients with pregnancy influenced issues like gestational diabetes mellitus, gestational hypertension, gastroesophageal reflux disease and anaemia. To assess the drug used pattern along with antibiotic therapy and to observe the above disease related complications.Methods: A hospital based prospective observational study was conducted at department of obstetrics and gynecology in Rajah Muthiah Medical College and Hospital. Totally 100 patients enrolled and data was collected using data collection form.Results: Out of 100 patients, high prevalence occurred in 26-30 years of age. Primarily gestational hypertension (39%), treated with Tab. Labetatol and complications were premature delivery, low birth weight. Anaemia (25%) cases treated with Tab. Ferrous sulphate, Iron sucrose and Folic Acid, Preterm delivery as complication. Gestational diabetes mellitus (18%) treated with Metformin and Human Insulin and complications were preterm delivery, maternal obesity, increased child weight. GERD (8%) treated with Pantoprazole, Ondansetron, Bifilac and complications were weight loss, dehydration, low birth weight. In pre-operative cases, 79% received antibiotics as monotherapy and 21% as dual therapy. In post-operative cases, 41% received antibiotics as monotherapy and 59% as dual therapy. Metronidazole (95%) given in both post and pre- operative conditions.Conclusions: The present study provides valuable insight about the overall drugs used in pregnancy related diseases and complications arise. We hope our data will make necessary recommendations to all health care professionals and pregnant women to ensure all pregnancy related safety measures were taken

Fabrication of polycaprolactone/β-tricalciumphosphate based nano scaffolds using electrospinning method for biomedical applications

1292-1297In this study, we have focused on preparation, fabrication and characterization of polycaprolactone and beta tricalcium phosphate (PCL/β-TCP) composite scaffolds that are used for bone tissue engineering applications. The electrospun composites have been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The developed scaffolds are effectively simulated the morphology, mechanical property and bioactivity for load-bearing tissue engineering applications. The bioactivity of the scaffolds has been evaluated with in vitro cell adhesion and growth studies. The results confirm the nontoxic behaviour of the composite biomaterials and developed scaffolds with MG-63 osteoblast-like cell line. The synthesized scaffolds have shown promising bioactivity with the growth as well as proliferation of new bone cells with considerable osteoconductive properties. The nanoscaffolds possess better physical properties and support high cell adhesion suggesting their application in bone tissue engineering field

Fabrication of polycaprolactone/β-tricalciumphosphate based nano scaffolds using electrospinning method for biomedical applications

In this study, we have focused on preparation, fabrication and characterization of polycaprolactone and beta tricalcium phosphate (PCL/β-TCP) composite scaffolds that are used for bone tissue engineering applications. The electrospun composites have been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The developed scaffolds are effectively simulated the morphology, mechanical property and bioactivity for load-bearing tissue engineering applications. The bioactivity of the scaffolds has been evaluated with in vitro cell adhesion and growth studies. The results confirm the nontoxic behaviour of the composite biomaterials and developed scaffolds with MG-63 osteoblast-like cell line. The synthesized scaffolds have shown promising bioactivity with the growth as well as proliferation of new bone cells with considerable osteoconductive properties. The nanoscaffolds possess better physical properties and support high cell adhesion suggesting their application in bone tissue engineering field

Synthesis and characterization of nano-hydroxyapatite/graphene oxide composite materials for medical implant coating applications

In this present work, nano-hydroxyapatite/Graphene Oxide were synthesized, and the composite were prepared in different ratios. The structural and morphological changes of synthesized nano hydroxyapatite, graphene oxide and reduced graphene oxide was investigated. Fourier Transform Infrared Spectrometer (FTIR) was used to investigate the chemical structural composition of the synthesized nano hydroxyapatite and its composite, which confirms that presence of presence of reduced graphene oxide, graphene oxide in the prepared composite. Field emission scanning electron microscopy (FE-SEM) analysis was employed to examine the surface morphology of the composite materials which confirms the presence graphene flakes and nanosized hydroxyapatite on the surface

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely