Factors influencing in-hospital length of stay and mortality in cancer patients suffering from febrile neutropenia

Introduction: Febrile neutropenia (FN) is a major complication of chemotherapy, costly in terms of morbidity, mortality and associated financial expenditure. The present study was conducted with the goal of highlighting FN as a serious problem in Pakistan, with the longer term objective of improved cancer survival, reduction in length of stay (LOS) in hospital, morbidity, mortality and costs in our existing developing country scenario. Methods: A cross-sectional descriptive study was conducted on Patients, \u3e or =18 years, admitted with FN as a consequence of chemotherapy at a referral hospital in Karachi from 1st September 2006 to 30th April 2007. Results: A total of 80 Patients [43 (53.8%) males and 37 (46.2%) females] were selected. The mean age was 47.4 (SD +/-16.6, range 18-79) years. Sixty eight Patients (86%) were \u3c or = 65 years, 50% were \u3c or = 50 years. Overall, inhospital mortality was 11%, 4% for Patients on granulocyte colony stimulating factor (G-CSF) prophylaxis as against 20% for those without. The cause of death was either pneumonia or septic shock. Mean LOS was 7.53 (SD +/-3.8, range 2-17) days. Hematological malignancies, older age, severity of dehydration, pneumonia and culture positivity were significantly associated with LOS and death. Those above 50 years of age were 1.5 times as likely to be hospitalized longer and \u3e three times as likely to die. Bacteremia conferred a 5-fold and pneumonia an 8-fold increase in the risk of death. Conclusion: The results of this study indicate that age, vital instability, dehydration, high creatinine, culture positivity and hematological malignancies are high risk factors in chemotherapy induced FN. Identification of FN risk factors with poor outcomes may help in devising protocols for modified dosage or including GCFs initially. This may help reduce the cost of cancer care as well as mortality and morbidity. Prospective studies of FN in multiple centers in Pakistan may be beneficial in evaluating these risk factors further

Ion-Pairing Limits Crystal Growth in Metal-Oxygen Batteries

Aprotic alkali metal-oxygen batteries are widely considered to be promising high specific energy alternatives to Li-ion batteries. The growth and dissolution of alkali metal oxides such as Li2O2 in Li-O2 batteries and NaO2 and KO2 in Na- and K-O2 batteries, respectively, is central to the discharge and charge processes in these batteries. However, crystal growth and dissolution of the discharge products, especially in aprotic electrolytes, is poorly understood. In this work, we chose the growth of NaO2 in Na-O2 batteries as a model system and show that there is a strong correlation between the electrolyte salt concentration and the NaO2 crystal size. With a combination of experiments and theory, we argue that the correlation is a direct manifestation of the strong cation-anion interactions leading to decreased crystal growth rate at high salt concentrations. Further, we propose and experimentally demonstrate that cation-coordinating crown molecules are suitable electrochemically stable electrolyte additives that weaken ion-pairing and enhance discharge capacities in metal-oxygen batteries while not negatively affecting their rechargeability.Comment: 13 Pages, 4 Figures, 14 pages of Supplementary Informatio

Neuromorphic computing using non-volatile memory

Dense crossbar arrays of non-volatile memory (NVM) devices represent one possible path for implementing massively-parallel and highly energy-efficient neuromorphic computing systems. We first review recent advances in the application of NVM devices to three computing paradigms: spiking neural networks (SNNs), deep neural networks (DNNs), and ‘Memcomputing’. In SNNs, NVM synaptic connections are updated by a local learning rule such as spike-timing-dependent-plasticity, a computational approach directly inspired by biology. For DNNs, NVM arrays can represent matrices of synaptic weights, implementing the matrix–vector multiplication needed for algorithms such as backpropagation in an analog yet massively-parallel fashion. This approach could provide significant improvements in power and speed compared to GPU-based DNN training, for applications of commercial significance. We then survey recent research in which different types of NVM devices – including phase change memory, conductive-bridging RAM, filamentary and non-filamentary RRAM, and other NVMs – have been proposed, either as a synapse or as a neuron, for use within a neuromorphic computing application. The relevant virtues and limitations of these devices are assessed, in terms of properties such as conductance dynamic range, (non)linearity and (a)symmetry of conductance response, retention, endurance, required switching power, and device variability.11Yscopu

Understanding Sub-20 nm Breakdown Behavior of Liquid Dielectrics

Nanoscale confinement of dielectric molecules is expected to influence their breakdown mechanism in applications such as nanoprobe based machining, molecular electronics, and other related technologies. This Letter presents the first experimental study of the breakdown of nonpolar, nonthiolated liquid dielectrics in the nanometer regime and develops a field emission assisted avalanche based approach to model such behavior. The studies show that dielectric breakdown in the sub-20 nm regime is independent of the cathode materials and is dominated by the electron emission and atomic cluster migration due to the ‘‘sub-20 nm scale confinement of the liquid dielectric.’

Surface Modification of Silicon Nano Mechanical Structures by Carbon Ion Implantation for Post-fabrication Transformation to Silicon Carbide

Internal stresses can cause de-lamination and fracture of coatings and structures and it is well known that ion-implantation can be used to control such behavior through modification of the stress. Here, however, we show that the unique ability of implantation to create controlled stresses in materials by altering both the chemical composition and mechanical properties, combined with an increase in the bending strength of materials, can used to create novel vertical nanostructures. Silicon cantilevers (beams), 193nm thick, 200nm wide and 3μm long, were implanted with carbon ions to create a buried SiCx layers. The internal stresses generated by implantation caused the beams to bend at angles ranging from 10 degrees to greater than 90 degrees, leading to unique vertical nanostructures. This method can be used to create 3-D nano electromechanical systems (NEMS)

Modification of Mechanical Properties of Silicon Nanocantilevers by Self-ion Implantation

The modification of Young's modulus of silicon 3D nanostructures were studied using self-ion implantation at liquid nitrogen temperatures. The Young's modulus of the silicon nanostructres were produced by the implantation of nanoscale beams with Si ions at energies of 100 and 35 keV and dose of 1×10 15 ions/cm 2. It was observed that the Young's modulus of the bimaterial silicon nanostructures were 150.3 and the modulus of amorphous silicon nanostructures were 134.5 GPa. The results show that the fundamental mechanical properties of silicon nanocantilevers is controllably modified using self-ion implantation at nanometer scale