Research advances in cognitive ultra wide band radio and their application to sensor networks

The paper illustrates the novel concept of Cognitive UWB Radio, a wireless system based on UWB transmission able to self-adapt to the characteristics of the surrounding environment. First, salient features of UWB transmission are reviewed, and then, application of UWB characteristics to the problem of cognitive radio systems is discussed. Current ongoing studies and achieved results on a possible physical layer based on Prolate Spheroidal Wave Functions and consistent with the Cognitive UWB Radio paradigm are presented and analyzed, and their application to the sensor network scenario is discussed.     

Chromatic dispersion measurement using a multiwavelength frequency-shifted feedback fiber laser

In this paper, we present the realization of a fiber laser source emitting simultaneously over 17 wavelengths spread over the whole C-band. An acoustooptic frequency shifter is placed in the laser ring cavity to suppress the cross-gain saturation effects of the erbium-doped fiber. The emitted wavelengths are fixed by a set of fiber Bragg gratings (FBGs). A power uniformity reaching 6 dB is achieved by inscribing the FBGs while monitoring the laser output. We demonstrate the reliability of this laser as a source for characterization of optical components and networks by the measurement of optical fiber chromatic dispersion. The measurement is performed over the whole telecommunication C-band (1530-1560 nm) using the time-of-flight method. We perform the measurement on three different fibers with different levels of dispersion, namely a standard fiber, a nonzero dispersion shifted fiber, and a dispersion compensating fiber. The results are compared with measurements obtained using a standard network analyzer. The agreement between the two methods is better than /spl plusmn/1%, thus proving the suitability of the developed laser source for this application.     

Modeling Evaporation-Seepage Losses for Reservoir Water Balance in Semi-arid Regions

In the water balance of reservoir system, evaporation plays a crucial role particularly so for the reservoir systems of smaller size located in the semi-arid or arid regions. Such regions are most often characterized by significant seepage losses from reservoirs, besides evaporation losses. Usually, in the optimization of a reservoir system, it is a common practice to assume evaporation loss either as some constant value or as negligible. Such assumptions, however, may affect the results of reservoir optimization. This is demonstrated in this study by a case study in the optimal scheduling of Pilavakkal reservoir system in Vaipar basin of Tamilnadu, India. For modeling reservoir losses, many models are available, of which, Penman combination model is most commonly used. In this study, an alternative approach based on Genetic Programming (GP) is proposed. The results of GP and Penman model for both evaporation loss estimation and reservoir scheduling are compared. It is found that while GP and Penman combination model performs equally well for estimating evaporation losses, GP is also able to model seepage losses (or other losses from reservoir) to a much better degree. It is also shown the reservoir scheduling does get influenced based on how the reservoir losses are modeled in the reservoir water balance equation.     

Double blind clinical and laboratory study of hypoglycaemia with human and porcine insulin in diabetic patients reporting hypoglycaemia unawareness after transferring to human insulin

OBJECTIVES: To compare awareness of hypoglycaemia and physiological responses to hypoglycaemia with human and porcine insulin in diabetic patients who reported loss of hypoglycaemia awareness after transferring to human insulin. DESIGN: Double blind randomised crossover study of clinical experience and physiological responses during slow fall hypoglycaemic clamping with porcine and human insulin. SETTING: Clinical investigation unit of teaching hospital recruiting from diabetes clinics of five teaching hospitals and one district general hospital. SUBJECTS: 17 patients with insulin dependent diabetes mellitus of more than five years' duration who had reported altered hypoglycaemia awareness within three months of transferring to human insulin. MAIN OUTCOME MEASURES: Glycaemic control and frequency of hypoglycaemic episodes during two months' treatment with each insulin. Glucose thresholds for physiological and symptomatic responses during clamping. RESULTS: Glycaemic control did not change with either insulin. 136 hypoglycaemic episodes (eight severe) were reported with human insulin and 149 (nine severe) with porcine insulin (95% confidence interval -4 to 2.5, p = 0.63). 20 episodes of biochemical hypoglycaemia occurred with human insulin versus 18 with porcine insulin (-0.8 to 1, p = 0.78). During controlled hypoglycaemia the mean adrenaline response was 138 nmol/l/240 min for both insulins; neurohormonal responses were triggered at 3.0 (SE 0.2) versus 3.1 (0.2) mmol/l of glucose for adrenaline and 2.5 (0.1) versus 2.5 (0.1) mmol/l for subjective awareness. CONCLUSIONS: These data suggest that human insulin per se does not affect the presentation of hypoglycaemia or the neurohumoral, symptomatic, and cognitive function responses to hypoglycaemia in insulin dependent diabetic patients with a history of hypoglycaemia unawareness.     

Cellular uptake of gold nanoparticles directly cross-linked with carrier peptides by osteosarcoma cells

Nanoparticles have been extensively used for a variety of biomedical applications and there is a growing need for highly specific and efficient delivery of the nanoparticles into target cells and subcellular location. We attempted to accomplish this goal by modifying gold particles with peptide motif's that are known to deliver a 'cargo' into chosen cellular location specifically, we intended to deliver nanogold particles into cells through chemical cross-linking with different peptides known to carry protein into cells. Our results suggest that specific sequence of such 'carrier peptides' can efficiently deliver gold nanoparticles into cells when chemically cross-linked with the metal particles.     

The nature of the head and neck cancer

Squamous cell carcinoma of the head and neck is a disease predominantly of males and is due to a variety of known environmental irritants, notably cigarette smoke. Dietary, viral and immunological factors may also be relevant. Head and neck squamous cancers express epidermal growth factor receptors and some show weak levels of oestrogen receptor activity, but a reliable serum marker of tumour burden remains to be identified. The prognosis is found to be less favourable in females, in those with advanced T stage, in association with multiple node involvement, especially where extracapsular spread is present and where the T4/T8 ratio is elevated. Administration of heterologous blood during therapy may also have an adverse effect on prognosis. Interested clinicians must remember that most cases are preventable.     

Frequent occurrence of diabetes mellitus after corticosteroid treatment in mixed cryoglobulinemia. An HCV-related complication?

The hepatitis C virus (HCV) infection is characterized by a variety of extra-hepatic manifestations in many individuals. Among these, diabetes mellitus (DM) can be included, as such a metabolic disorder has been demonstrated to be more frequent in chronic hepatitis C than in liver disease due to other causes. Recently, we have observed that most patients affected with HCV-associated mixed cryoglobulinemia (13 out of 15, 86.7%), that were at baseline normoglycemic, developed DM following corticosteroid treatment (prednisone > 25 mg/daily) for at least three months. Conversely, when we consider a control group including 36 HCV negative patients affected with various immunomediated disorders, i.e., systemic lupus erythematosus, myasthenia gravis, poly/dermatomyositis and chronic inflammatory demyelinating polyneuropathy, that were initially normoglycemic, corticosteroid induced DM (prednisone > 25 mg/daily for at least three months) occurred only in 16.7% of subjects. Moreover, in other two HCV positive patients suffering from myasthenia gravis, prolonged corticosteroid treatment was complicated by DM. These data, that are still unclear from a pathophysiologic viewpoint, seem to indicate corticosteroid induced DM as a further, unusual extra-hepatic manifestation of the HCV infection.     

Aggregation-Enhanced Photoluminescence and Photoacoustics of Atomically Precise Gold Nanoclusters in Lipid Nanodiscs (NANO2)

The authors designed a structurally stable nano-in-nano (NANO²) system highly capable of bioimaging via an aggregation-enhanced NIR excited emission and photoacoustic response achieved based on atomically precise gold nanoclusters protected by linear thiolated ligands [Au₂₅(SC_nH_2n+1)₁₈, n  = 4–16] encapsulated in discoidal phospholipid bicelles through a one-pot synthesis. The detailed morphological characterization of NANO² is conducted using cryogenic transmission electron microscopy, small/wide angle X-ray scattering with the support of molecular dynamics simulations, providing information on the location of Au nanoclusters in NANO². The photoluminescence observed for NANO² is 20–60 times more intense than that of the free Au nanoclusters, with both excitation and emission wavelengths in the near-infrared range, and the photoacoustic signal is more than tripled. The authors attribute this newly discovered aggregation-enhanced photoluminescence and photoacoustic signals to the restriction of intramolecular motion of the clusters’ ligands. With the advantages of biocompatibility and high cellular uptake, NANO² is potentially applicable for both in vitro and in vivo imaging, as the authors demonstrate with NIR excited emission from in vitro A549 human lung and the KB human cervical cancer cells.