A microchip optomechanical accelerometer

The monitoring of accelerations is essential for a variety of applications ranging from inertial navigation to consumer electronics. The basic operation principle of an accelerometer is to measure the displacement of a flexibly mounted test mass; sensitive displacement measurement can be realized using capacitive, piezo-electric, tunnel-current, or optical methods. While optical readout provides superior displacement resolution and resilience to electromagnetic interference, current optical accelerometers either do not allow for chip-scale integration or require bulky test masses. Here we demonstrate an optomechanical accelerometer that employs ultra-sensitive all-optical displacement read-out using a planar photonic crystal cavity monolithically integrated with a nano-tethered test mass of high mechanical Q-factor. This device architecture allows for full on-chip integration and achieves a broadband acceleration resolution of 10 \mu g/rt-Hz, a bandwidth greater than 20 kHz, and a dynamic range of 50 dB with sub-milliwatt optical power requirements. Moreover, the nano-gram test masses used here allow for optomechanical back-action in the form of cooling or the optical spring effect, setting the stage for a new class of motional sensors.Comment: 16 pages, 9 figure

Adjusting Phenotypes by Noise Control

Genetically identical cells can show phenotypic variability. This is often caused by stochastic events that originate from randomness in biochemical processes involving in gene expression and other extrinsic cellular processes. From an engineering perspective, there have been efforts focused on theory and experiments to control noise levels by perturbing and replacing gene network components. However, systematic methods for noise control are lacking mainly due to the intractable mathematical structure of noise propagation through reaction networks. Here, we provide a numerical analysis method by quantifying the parametric sensitivity of noise characteristics at the level of the linear noise approximation. Our analysis is readily applicable to various types of noise control and to different types of system; for example, we can orthogonally control the mean and noise levels and can control system dynamics such as noisy oscillations. As an illustration we applied our method to HIV and yeast gene expression systems and metabolic networks. The oscillatory signal control was applied to p53 oscillations from DNA damage. Furthermore, we showed that the efficiency of orthogonal control can be enhanced by applying extrinsic noise and feedback. Our noise control analysis can be applied to any stochastic model belonging to continuous time Markovian systems such as biological and chemical reaction systems, and even computer and social networks. We anticipate the proposed analysis to be a useful tool for designing and controlling synthetic gene networks

Hospital-acquired infections following the 1999 Marmara earthquake

In this study, medical records of all casualties admitted to our hospital following the Marmara earthquake, which struck northwest Turkey and resulted in the destruction of several towns in the Marmara region, were evaluated retrospectively. The time buried under the rubble, demographic data, type of medical and surgical therapies performed, type of injury and data on infection were analysed. Between 17 August and 25 September 1999, 630 trauma victims were received at our hospital and 532 (84%) of them were hospitalized. The mean age of hospitalized patients (312 males, 220 females) was 32 years (2-90 years). Two hundred and twenty patients were hospitalized for more than 48 h. Forty-one of them (18.6%) had 43 hospital-acquired infection (HAI) episodes, which were mostly wound infections (46.5%). A total of 143 culture specimens was collected and 48 yielded the following potential pathogens: 15 Acinetobacter baumanii (31.2%), nine Staphylococcus aureus (18.7%), seven Pseudomonas aeruginosa (14.6%), six Escherichia coli (12.5%), six Klebsiella pneumoniae (12.5%), two Stenotrophomonas maltophilia (4.2%) and three various Pseudomonas spp. (6.3%). All S. aureus strains were found to be resistant to methicillin in vitro. Two strains of A. baumannii and one P. aeruginosa were found to be resistant to all antimicrobials including carbapenems. Fifty-three victims died (10%) and 36 of those died during the first 48 h because of severe injuries and multi-organ failure. After 48 h of hospitalization, the mortality rate was significantly higher in those patients with HAI (14/41) than those without (3/179) (34.1% vs. 1.7%, P < 0.05). In conclusion, trauma is the significant factor associated with HAI and a high incidence of Acinetobacter strains was responsible for HAI in trauma patients. (C) 2002 The Hospital Infection Society

T-wave loop area from a pre-implant 12-lead ECG is associated with appropriate ICD shocks

AIMS: In implantable cardioverter-defibrillator (ICD) patients, predictors of ICD shocks and mortality are needed to improve patient selection. Electrocardiographic (ECG) markers are simple to obtain and have been demonstrated to predict mortality. We aimed to assess the association of T-wave loop area and circularity with ICD shocks. METHODS: The study investigated patients with ICDs implanted between 1998 and 2010 for whom digital 12-lead ECGs (Schiller CS200 ECG-Network) of sufficient quality were obtained within 1 month prior to the implantation. T-wave loop area and circularity were calculated. Follow-up data of appropriate shocks were obtained during ICD clinic visits that included reviews of device stored electrograms. RESULTS: A total of 605 patients (82% males) were included; 68% had ischemic cardiomyopathy and 72% were treated for primary prevention. Over 3.8±1.4 years of follow-up, 114 patients (19%) experienced appropriate shock(s). Those with smaller T-wave loop area received fewer shocks (TLA, hazard ratio, HR, per increase of 1 technical unit, 0.71; [95% confidence interval, 0.53-0.94]; P = 0.02) and those with larger T-wave loop circularity (TLC) representing rounder T wave loop received more shocks (HR per 1% TLC increase 2.96; [0.85-10.36]; P = 0.09). When the quartile containing the largest TLA and TLC values, respectively, were compared to the remaining cases, TLA remained significantly associated with fewer and TLC with more frequent shocks also after multivariate adjustment for clinical variables (HR, 0.59 [0.35-0.99], P = 0.044; and 1.64 [1.08-2.49], P = 0.021, respectively). CONCLUSIONS: The size and shape of the T-wave loop calculated from pre-implantation 12-lead ECGs are associated with appropriate ICD shocks.Open-Access-Publikationsfonds 2017Open-Access-Publikationsfonds 2017peerReviewe

Caregivers' practices, knowledge and beliefs of antibiotics in paediatric upper respiratorytract infections in Trinidad and Tobago: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Antibiotic overuse and misuse for upper respiratory tract infections in children is widespread and fuelled by public attitudes and expectations. This study assessed knowledge, beliefs, and practices regarding antibiotic use for these paediatric infections among children's caregivers' in Trinidad and Tobago in the English speaking Caribbean.</p> <p>Methods</p> <p>In a cross-sectional observational study, by random survey children's adult caregivers gave a telephone interview from November 1998 to January 1999. On a pilot-tested evaluation instrument, respondents provided information about their knowledge and beliefs of antibiotics, and their use of these agents to treat recent episodes (< previous 30 days) of upper respiratory tract infections in children under their care. Caregivers were scored on an antibiotic knowledge test and divided based on their score. Differences between those with high and low scores were compared using the chi-square test.</p> <p>Results</p> <p>Of the 417 caregivers, 70% were female and between 18–40 years, 77% were educated to high school and beyond and 43% lived in urban areas. Two hundred and forty nine (60%) respondents scored high (≥ 12) on antibiotic knowledge and 149 (34%) had used antibiotics in the preceding year. More caregivers with a high knowledge score had private health insurance (33%), (p < 0.02), high school education (57%) (p < 0.002), and had used antibiotics in the preceding year (p < 0.008) and within the last 30 days (p < 0.05). Caregivers with high scores were less likely to demand antibiotics (p < 0.05) or keep them at home (p < 0.001), but more likely to self-treat with antibiotics (p < 0.001). Caregivers administered antibiotics in 241/288 (84%) self-assessed severe episodes of infection (p < 0.001) and in 59/126 (43%) cough and cold episodes without visiting a health clinic or private physician (p < 0.05).</p> <p>Conclusions</p> <p>In Trinidad and Tobago, caregivers scoring low on antibiotic knowledge have erroneous beliefs and use antibiotics inappropriately. Children in their care receive antibiotics for upper respiratory tract infections without visiting a health clinic or a physician. Educational interventions in the community on the consequences of inappropriate antibiotic use in children are recommended. Our findings emphasise the need to address information, training, legislation and education at all levels of the drug delivery system towards discouraging self-medication with antibiotics in children.</p

Is acupuncture "stimulation" a misnomer? A case for using the term " blockade"

Background: The term used most frequently in the literature to describe acupuncture's effects is " stimulation" which may be used to describe either (or both) the direct stimulus applied to a needle as well as putative stimulation of the nervous system, despite little published evidence describing what is actually being stimulated. In contrast, recent published work has suggested that acupuncture may, in fact be inhibitory at a peripheral level, acting by blocking neural transmission.Discussion: The suggestion that acupuncture exerts its effects through peripheral neural blockade is supported by recent evidence explaining related techniques including low level laser and capsaicin at acupoints. It also explains acupuncture's effect on painful and non-painful conditions and both Eastern and Western concepts of acupuncture. There is a need for additional work to elucidate acupuncture's mechanism of action, and the suggestion that it acts through neural blockade should prompt further research in this direction.Summary: If the term " blockade" were applied to acupuncture, this would, likely, be expected to promote this minimally invasive technique, and, potentially, bring it into mainstream clinical practice for pain management as well as other therapeutic applications. © 2013 Silberstein; licensee BioMed Central Ltd