Packet scheduling in 3.5G high-speed downlink packet access networks: breadth and depth

Forecasts for emerging mobile device markets anticipate that bandwidth will be squeezed by demanding applications like multimedia on demand. This will spur the need for data rates beyond what the upcoming 3G wireless cellular systems such as UMTS can offer. To boost the support for such high data rates, HSDPA, labeled as a 3.5G wireless system, has been introduced in Release 5 of UMTS technical specifications. HSDPA is a definite step toward meeting the "anywhere, anytime, and in any form" 4G communication concept. HSDPA promises a peak data rate of up to 10 Mb/s, five times larger than the data rate offered by 3G systems. In order to support such high data rates, HSDPA relies on many new technologies, among which is packet scheduling. In this article we provide breadth and depth related issues of packet scheduling in HSDPA, discuss state-of-the-art HSDPA scheduling algorithms in terms of their objectives, advantages, and limitations, and suggest further research issues that need to be addressed. In addition, we propose a packet scheduling algorithm for data traffic in HSDPA. Simulation results demonstrate the effectiveness of the proposed algorithm     

Discovery and structure-activity relationship of the first non-peptide competitive human glucagon receptor antagonists

The first non-peptide competitive human glucagon receptor antagonist, 2-(benzimidazol-2-ylthio)-1-(3,4-dihydroxyphenyl)-1-ethan one, NNC 92-1687 (2), is described. This antagonist has a binding affinity of 20 microM (IC50) and a functional Ki = 9.1 microM at the human glucagon receptor. A structure-activity relationship (SAR) was obtained on this compound, and the results show that only the benzimidazole part can be changed without complete loss of affinity. Analogues with tert-butyl or benzyloxy groups in the 5-position of the benzimidazole moiety were found to be equipotent or slightly more potent, all displaying binding affinities around 5-20 microM. Most of the changes to the catechol and the linker gave compounds without any affinity toward the human glucagon receptor. The 3-hydroxy group could, however, in the presence of a 4-hydroxy group be changed to a methoxy or a chloro group while retaining affinity.     

Increased incidence of cancer in infants in the U.S.: 1980-1990

BACKGROUND: During the decade between 1980-1990, the rate of cancer in children in the U.S. increased. It is unknown whether cancer in infancy, which is biologically and clinically different from cancer in older children, also increased. METHODS: To evaluate changes in cancer incidence in infants in the U.S. age < 1 year, data from the Surveillance, Epidemiology, and End Results (SEER) program and the U.S. Bureau of the Census were used to construct age specific, population-based cancer incidence rates. RESULTS: Overall, the annual cancer rate in infants increased from 189 cases per million infants between 1979-1981 to 220 between 1989-1991. At both timepoints, female infants had higher cancer rates than male infants. Although the rates for female infants remained stable at 223 between 1979-1981 versus 236 between 1989-1991, rates for male infants increased from 158 to 205 during the same timepoints. Male infants had increased rates of central nervous system (CNS) tumors (P < 0.05), neuroblastoma, and retinoblastoma; female infants had increased rates of teratomas (P < 0.01) and hepatoblastomas. Between 1979-1981, the three most common types of cancer in infants were neuroblastoma, leukemia, and renal tumors (27%, 15%, and 14%, respectively), and were neuroblastoma, CNS tumors, and leukemia between 1989-1991 (27%, 15%, and 13%, respectively). CONCLUSIONS: This study shows that the rate of certain types of cancer in infants in the U.S. is increasing. Studies of both genetic and environmental factors are needed to explain these increased rates and the changing distribution of cancer in the first year of life.     

Pituitary adenylate cyclase activating polypeptide (PACAP) is localized in human dermal neurons and causes histamine release from skin mast cells

OBJECTIVE AND DESIGN: Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide homologous with vasoactive intestinal polypeptide (VIP) which is known to induce histamine release in human skin mast cells. PACAP has not been detected in human skin. The purposes of the study were to investigate the occurrence of PACAP in human skin and to evaluate the histamine releasing activity of the two common pro-PACAP products, PACAP-27 and PACAP-38. MATERIAL: Fourteen human surgical skin samples were obtained. PACAP and VIP were visualized by immunohistochemistry. A microdialysis technique was used to measure histamine release in intact skin samples following intradermal injections of the peptides. RESULTS: PACAP and VIP were localized in dermal nerves in connection with sweat glands. Intradermal injection of 3 or 10 microm PACAP significantly released histamine. Kinetics of histamine release showed peak release 2-4 min after skin challenge. Ten microm of PACAP-27, VIP and somatostatin caused histamine release with similar efficacy, whereas PACAP-38 was less effective. Substance P was twice as efficient as PACAP-27, whereas calcitonin gene-related peptide did not release histamine. CONCLUSIONS: PACAP is found in human skin and is capable of releasing histamine from skin mast cells.     

Is intermittent pulsatile pressure a valuable adjunct in healing the complicated diabetic wound?

Diabetic neuropathic ulceration and subsequent lower extremity amputation are a significant cause of chronic disability. High-risk diabetic patients with infected foot wounds, poor lower extremity blood flow, and inadequately controlled blood glucose require prompt action by clinicians in order to successfully avoid more severe sequelae. Dysvascular patients who are poor candidates for arterial bypass surgery may benefit from adjunctive treatment with a pneumatic pedal compression device. The authors discuss the rationale behind this unique treatment modality and present a case report illustrating a successful outcome in a high-risk diabetic patient.     

Ethical issues in gynecology

This review cites new evidence suggesting a link between the recently discovered membrane bound water-selective channel, aquaporin-4 (AQP4), and the mechanism of central osmoreception. AQP4 is found in a number of brain regions associated with the osmoregulation of vasopressin secretion and thirst, including the supraoptic nucleus (SON) and subfornical organ (SFO). AQP4 expression is restricted to ependymal cell membranes in the SFO and astrocyte membranes in the SON, especially perivascular end foot processes, suggesting that glial cells may correspond to Verney's hypothalamic 'vesicular osmometers'. Information on osmotic status may thus be conveyed to the neuronal elements of the 'osmoreceptor complex' by a neurone-glial interaction.     

Cloning of the maoA gene that encodes aromatic amine oxidase of Escherichia coli W3350 and characterization of the overexpressed enzyme

The mao operon of Escherichia coli W3350, which comprises the genes maoC and maoA, was cloned and appeared to be similar to that of Klebsiella aerogenes [Sugino, H., Sasaki, M., Azakami, H., Yamashita, M. & Murooka, Y. (1992) J. Bacteriol. 174, 2485-2492]. The gene that encodes aromatic amine oxidase (maoA) was isolated, sequenced, and expressed in E. coli TG2. The purified enzyme exhibited properties characteristic of a copper/topaquinone(TPQ)-containing amine oxidase with respect to the optical absorption and EPR spectra, the size of the subunits, and the optical absorption spectra obtained upon derivatization with hydrazines. However, high-resolution anion-exchange chromatography revealed that the preparation was heterogeneous. The enzyme preparation appeared to consist of at least four enzyme species with different specific activities, A474nm/A340nm ratios and TPQ/subunit ratios. Since the overall properties of the overexpressed enzyme and the authentic enzyme were similar and the separated enzyme species had identical N-terminal amino acid sequences, the heterogeneity does not seem to be caused by improper expression of the gene in the recombinant strain but by factors that interfere with the processing of the specific tyrosine in the precursor enzyme to functional TPQ. Although other causes cannot be excluded, the spectral data and TPQ/subunit ratios reported in the literature for other amine oxidases suggest that suboptimal synthesis of functional TPQ also occurs in other organisms.     

Modeling the contribution of pig farming to pollution of the Thachin River

Rapid growth of the livestock production sector in South-East Asia during recent decades has led to a widespread degradation of ground and surface waters. The Thachin River Basin in Central Thailand serves as a case study for investigating the origins and pathways of nutrient loads produced by intensive pig farming. A mathematical material flow analysis is used to identify key nitrogen flows and the main parameters determining them. Scenarios of the potential for reducing these flows and achieving compliance with current discharge regulations are investigated. The results show that liquid waste discharged from large pig farms and directly discharged waste from small farms are the key nitrogen flows to the river system. The key driving forces are not only the treatment coverage and efficiencies but also the rate of reuse and recycling of the treated product.