Hypothermia for perinatal asphyxial encephalopathy. A Swiss survey of opinion, practice and cerebral investigations

BACKGROUND: Perinatal asphyxial encephalopathy occurs in 1-per 1000 live births and is associated with high mortality and morbidity. Therapeutic hypothermia increases intact survival and improves neurodevelopmental outcome in survivors.AIMS: To evaluate (i) the opinion and practice of therapeutic hypothermia as a therapy for moderate to severe perinatal asphyxial encephalopathy amongst Swiss neonatologists and paediatric intensive care specialists, (ii) the current clinical management of infants with perinatal asphyxial encephalopathy and (iii) the need for a national perinatal asphyxia and therapeutic hypothermia registry.METHODS: Two web-based questionnaires were sent to 18 senior staff physicians within the Swiss Neonatal Network.RESULTS: Therapeutic hypothermia was considered effective by all responders, however only 11 of 18 units provided therapeutic hypothermia. Cooling was initiated during transfer and performed passively in 82% of centres with a target rectal temperature of 33-34 degrees C. Most units ventilated infants with perinatal asphyxial encephalopathy if clinically indicated and 73% of responders gave analgesia routinely to cooled infants. Neuromonitoring included continuous amplitude integrated EEG (aEEG) and EEG. Neuroimaging included cranial ultrasound (cUS), magnetic resonance imaging (MRI) and computed tomography (CT). Sixty-seven percent of units treating infants with perinatal asphyxial encephalopathy performed MRI routinely. All heads of departments questioned indicated that a "Swiss National Asphyxia and Cooling Registry" is needed.CONCLUSIONS: In Switzerland, access to therapeutic hypothermia is widespread and Swiss neonatologists believe that therapeutic hypothermia for perinatal asphyxia is effective. National cooling protocols are needed for the management of infants with perinatal asphyxial encephalopathy in order to ensure safe cooling, appropriate monitoring, imaging and follow-up assessment. A national registry is needed to collect data on diagnosis, treatment, adverse events and outcome

Almost Perfect Privacy for Additive Gaussian Privacy Filters

We study the maximal mutual information about a random variable $Y$ (representing non-private information) displayed through an additive Gaussian channel when guaranteeing that only $\epsilon$ bits of information is leaked about a random variable $X$ (representing private information) that is correlated with $Y$. Denoting this quantity by $g_\epsilon(X,Y)$, we show that for perfect privacy, i.e., $\epsilon=0$, one has $g_0(X,Y)=0$ for any pair of absolutely continuous random variables $(X,Y)$ and then derive a second-order approximation for $g_\epsilon(X,Y)$ for small $\epsilon$. This approximation is shown to be related to the strong data processing inequality for mutual information under suitable conditions on the joint distribution $P_{XY}$. Next, motivated by an operational interpretation of data privacy, we formulate the privacy-utility tradeoff in the same setup using estimation-theoretic quantities and obtain explicit bounds for this tradeoff when $\epsilon$ is sufficiently small using the approximation formula derived for $g_\epsilon(X,Y)$.Comment: 20 pages. To appear in Springer-Verla

Metastability in the dilute Ising model

Consider Glauber dynamics for the Ising model on the hypercubic lattice with a positive magnetic field. Starting from the minus configuration, the system initially settles into a metastable state with negative magnetization. Slowly the system relaxes to a stable state with positive magnetization. Schonmann and Shlosman showed that in the two dimensional case the relaxation time is a simple function of the energy required to create a critical Wulff droplet. The dilute Ising model is obtained from the regular Ising model by deleting a fraction of the edges of the underlying graph. In this paper we show that even an arbitrarily small dilution can dramatically reduce the relaxation time. This is because of a catalyst effect---rare regions of high dilution speed up the transition from minus phase to plus phase.Comment: 49 page

Estimation of a probability in inverse binomial sampling under normalized linear-linear and inverse-linear loss

Sequential estimation of the success probability $p$ in inverse binomial sampling is considered in this paper. For any estimator $\hat p$, its quality is measured by the risk associated with normalized loss functions of linear-linear or inverse-linear form. These functions are possibly asymmetric, with arbitrary slope parameters $a$ and $b$ for $\hat pp$ respectively. Interest in these functions is motivated by their significance and potential uses, which are briefly discussed. Estimators are given for which the risk has an asymptotic value as $p$ tends to $0$, and which guarantee that, for any $p$ in $(0,1)$, the risk is lower than its asymptotic value. This allows selecting the required number of successes, $r$, to meet a prescribed quality irrespective of the unknown $p$. In addition, the proposed estimators are shown to be approximately minimax when $a/b$ does not deviate too much from $1$, and asymptotically minimax as $r$ tends to infinity when $a=b$.Comment: 4 figure

Probing anomalous tbW couplings in single-top production using top polarization at the Large Hadron Collider

We study the sensitivity of the Large Hadron Collider (LHC) to anomalous tbW couplings in single-top production in association with a W^- boson followed by semileptonic decay of the top. We calculate top polarization and the effects of these anomalous couplings to it at two centre-of-mass (cm) energies of 7 TeV and 14 TeV. As a measure of top polarization, we look at various laboratory frame distributions of its decay products, viz., lepton angular and energy distributions and b-quark angular distributions, without requiring reconstruction of the rest frame of the top, and study the effect of anomalous couplings on these distributions. We construct certain asymmetries to study the sensitivity of these distributions to anomalous tbW couplings. We find that 1\sigma limits on real and imaginary parts of the dominant anomalous coupling Ref_{2R} which may be obtained by utilizing these asymmetries at the LHC with cm energy of 14 TeV and an integrated luminosity of 10 fb^{-1} will be significantly better than the expectations from direct measurements of cross sections and some other variables at the LHC and over an order of magnitude better than the indirect limits.Comment: 25 pages, 34 figure

Identification of a tyrosine residue responsible for N-acetylimidazole-induced increase of activity of ecto-nucleoside triphosphate diphosphohydrolase 3

Chemical modification in combination with site-directed mutagenesis was used to identify a tyrosine residue responsible for the increase in ecto-nucleoside triphosphate diphosphohydrolase 3 (NTPDase3) nucleotidase activity after acetylation with a tyrosine-selective reagent, N-acetylimidazole. The NTPDase3 ATPase activity is increased more than the ADPase activity by this reagent. Several fairly well conserved tyrosine residues (252, 255, and 262) that are located in or very near apyrase conserved region 4a (ACR4a) were mutated. These mutants were all active, but mutation of tyrosine 252 to either alanine or phenylalanine eliminated the activity increase observed after N-acetylimidazole treatment of the wild-type enzyme. This suggests that the acetylation of tyrosine 252 is responsible for the increased activity. Stabilization of quaternary structure has resulted in increased enzyme activities for the NTPDases. However, mutation of these three tyrosine residues did not result in global changes of tertiary or quaternary structure, as measured by Cibacron blue binding, chemical cross linking, and native gel electrophoretic analysis. Nevertheless, disruption of the oligomeric structure with the detergent Triton X-100 abolished the increase in activity induced by this reagent. In addition, mutations that abolished the N-acetylimidazole effect also attenuated the increases of enzyme activity observed after lectin and chemical cross-linking treatments, which were previously attributed to stabilization of the quaternary structure. Thus, we speculate that the acetylation of tyrosine 252 might induce a subtle conformational change in NTPDase3, resulting in the observed increase in activity

The course of mental health problems in children presenting with abdominal pain in general practice

Objective. To investigate the course of mental health problems in children presenting to general practice with abdominal pain and to evaluate the extent to which abdominal pain characteristics during follow-up predict the presence of mental health problems at 12 months' follow-up. Design. A prospective cohort study with one-year follow-up. Setting. 53 general practices in the Netherlands, between May 2004 and March 2006. Subjects. 281 children aged 4-17 years. Main outcome measures. The presence of a depressive problem, an anxiety problem, and multiple non-specific somatic symptoms at follow-up and odds ratios of duration, frequency, and severity of abdominal pain with these mental health problems at follow-up. Results. A depressive problem persisted in 24/74 children (32.9%; 95% CI 22.3-44.9%), an anxiety problem in 13/43 (30.2%; 95% CI 17.2-46.1%) and the presence of multiple non-specific somatic symptoms in 75/170 children (44.1%; 95% CI 36.7-51.6%). None of the abdominal pain characteristics predicted a depressive or an anxiety problem at 12 months' follow-up. More moments of moderate to severe abdominal pain predicted the presence of multiple nonspecific somatic symptoms at follow-up. Conclusions. In one-third of the children presenting to general practice for abdominal pain, anxiety and depressive problems persist during one year of follow-up. Characteristics of the abdominal pain during the follow-up period do not predict anxiety or depressive problems after one-year follow-up. We recommend following over time children seen in primary care with abdominal pain

Cloning and characterization of the ecto-nucleotidase NTPDase3 from rat brain: Predicted secondary structure and relation to other members of the E-NTPDase family and actin

The protein family of ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDase family) contains multiple members that hydrolyze nucleoside 5’-triphosphates and nucleoside 5’-diphosphates with varying preference for the individual type of nucleotide. We report the cloning and functional expression of rat NTPDase3. The rat brain-derived cDNA has an open reading frame of 1590 bp encoding 529 amino acid residues, a calculated molecular mass of 59.1 kDa and predicted N- and C-terminal hydrophobic sequences. It shares 94.3% and 81.7% amino acid identity with the mouse and human NTPDase3, respectively, and is more closely related to cell surface-located than to the intracellularly located members of the enzyme family. The NTPDase3 gene is allocated to chromosome 8q32 and organized into 11 exons. Rat NTPDase3 expressed in CHO cells hydrolyzed both nucleoside triphosphates and nucleoside diphosphates with hydrolysis ratios of ATP:ADP of 5:1 and UTP:UDP of 8:1. After addition of ATP, ADP is formed as an intermediate product that is further hydrolyzed to AMP. The enzyme is preferentially activated by Ca2+ over Mg2+ and reveals an alkaline pH optimum. Immunocytochemistry confirmed expression of heterologously expressed NTPDase3 to the surface of CHO cells. PC12 cells express endogenous surface-located NTPDase3. An immunoblot analysis detects NTPDase3 in all rat brain regions investigated. An alignment of the secondary structure domains of actin conserved within the actin/HSP70/sugar kinase superfamily to those of all members of the NTPDase family reveals apparent similarity. It infers that NTPDases share the two-domain structure with members of this enzyme superfamily

Nanomechanical Detection of Itinerant Electron Spin Flip

Spin is an intrinsically quantum property, characterized by angular momentum. A change in the spin state is equivalent to a change in the angular momentum or mechanical torque. This spin-induced torque has been invoked as the intrinsic mechanism in experiments ranging from the measurements of angular momentum of photons g-factor of metals and magnetic resonance to the magnetization reversal in magnetic multi-layers A spin-polarized current introduced into a nonmagnetic nanowire produces a torque associated with the itinerant electron spin flip. Here, we report direct measurement of this mechanical torque and itinerant electron spin polarization in an integrated nanoscale torsion oscillator, which could yield new information on the itinerancy of the d-band electrons. The unprecedented torque sensitivity of 10^{-22} N m/ \sqrt{Hz} may enable applications for spintronics, precision measurements of CP-violating forces, untwisting of DNA and torque generating molecules.Comment: 14 pages, 4 figures. visit http://nano.bu.edu/ for related paper