Utilization of the same DNA replication origin by human cells of different derivation

In the past, a highly sensitive and efficient method was developed to map DNA replication origins in human cells, based on quantitative PCR performed on nascent DNA samples. This method allowed the identification of a replication origin in the myeloid HL-60 cell line, located on chromosome 19 within an approximately 500 bp segment near the lamin B2 gene [Giacca et al. (1994) Proc. Natl. Acad. Sci. USA, 91, 7119]. The same procedure has now been further simplified and extended to a variety of other exponentially growing human cells of different histological derivation (three neural, one connectival and one epithelial), with a nearly diploid chromosomal content. In all the six cell lines tested, the origin activity within the lamin B2 gene domain was localized to the same region. Furthermore, the lamin B2 origin was also found to be active in stimulated, but not in quiescent, peripheral blood lymphocytes.     

Cloud-induced effects on monthly averaged scintillation amplitude along millimeter-wave slant paths

A physical-statistical analysis of cloud-induced effects on millimeter-wave amplitude scintillation along Earth-satellite slant paths is presented. Using numerical simulations derived from a cloud radiative model, a dual-channel nonlinear retrieval algorithm is set up to estimate simultaneously cloud columnar water vapor and liquid water contents from measured ground-based brightness temperatures. The latter are related in cloudy conditions to surface meteorological variables and columnar water vapor and liquid water contents. ITALSAT ground-station data consisting of time series of beacon scintillation at 18.7, 39.6, and 49.5 GHz, surface meteorological data and radiometric observations at 13.0, 23.8, and 31.6 GHz, are used for an experimental analysis of cloud-induced scintillation by selecting a period of six years from 1994 to 1999. The results show a significant correlation between amplitude scintillation variances and cloud columnar contents on a monthly basis (i.e., averaged on-time intervals of one month). Considerations about possible impact of this analysis on the development of scintillation prediction models are finally illustrated.     

Heat treatment modifies the allergenicity of beef and bovine serum albumin

The effect of heat on the allergenicity of beef and bovine serum albumin was investigated among 10 toddlers skin prick test (SPT)-positive to raw and cooked beef. The meat-allergy diagnosis was confirmed during double-blind, placebo-controlled food challenge (DBPCFC) with 180 g of beef cooked for 5 min at 100 degrees C. SPT with homogenized and freeze-dried beef, and heated and unheated bovine serum albumin were performed. Both heated and unheated bovine serum albumin, homogenized beef, and freeze-dried beef were used in trial DBPCFC. All children were SPT-positive to unheated bovine serum albumin. Seven were positive to heated bovine serum albumin, one to freeze-dried beef, and none to homogenized beef. DBPCFCs were negative for homogenized beef and freeze-dried beef, positive for unheated bovine serum albumin in five patients, and positive for heated albumin in four children. We conclude that heating reduces sensitization to beef and bovine serum albumin but does not abolish reactivity to albumin under home conditions. However, industrially heat-treated and sterilized homogenized beef and freeze-dried beef may be suitable substitutes in beef-allergic children's diets.     

Ultrasonography-guided identification of the lumbar epidural space

The study was designed to assess the reliability of sonographic evaluation in the prediction of the depth of the lumbar epidural space. Forty males, scheduled for epidural anesthesia for surgical repair of inguinal hernia, were prospectively studied. Patients were placed in a sitting position and sagittal scanning of the lumbar spine was performed with a 5-MHz transducer over the fourth or fifth interspace in order to identify the deeper hyperechogen interface, which represents the landmark between the ligamentum flavum and the epidural space. Ultrasound depth was measured and transducer removed. A Tuohy needle 18 G was then introduced percutaneously according to the standard technique and a rubber slide placed over it, so that it depth of insertion could be accurately measured. The potential for using ultrasounds for prediction of the distance from skin to epidural space was analyzed using a simple linear regression analysis; p values < 0.05 were considered significant. Mean values of ultrasound depth and needle depth were respectively 51 mm (SD 6.3) and 50.9 mm (SD 6.2); the correlation coefficient was 0.99. Ultrasound scanning of the lumbar spine provides an accurate measurement of the depth of the epidural space, which can facilitate the performance of the epidural anaesthesia and may decrease the complication rate, particularly in those patients in which anatomic landmarks are obscured.     

Scanning electron microscopy of proteoglycans in metaphyseal cartilage.

Alcian blue (AB) was used for scanning electron microscope investigations on metaphyseal cartilage. In the pericellular area three-dimensional network connecting the cell membrane surface to the lacunar wall is evident. The network is formed by very long rod-like filaments about 50 nm thick. The segments may be interpreted as the proteoglycans (PGs) of the pericellular area. In the pericellular area in hypertrophic and degenerative zones, the rod-like segments are closely connected to "chain granules" which are the morphological expression of Ca-P non crystalline compounds. The rod-like segments are not at all evident either in glutaraldehyde-osmium fixed fragments or in predigested-(streptococcal hyaluronidase and chondroitinase) AB stained ones. It is concluded that AB is a good method to detect the three-dimensional spatial disposition of cartilage PGs.     

Performance of synthetic storm technique in estimating fade dynamics in equatorial Malaysia

In this paper, the synthetic storm technique (SST) is applied to 1‐minute rainfall rate collected from a rain gauge to predict the fade dynamics of the signal in an earth‐to‐satellite link in an equatorial climate location without the needs of satellite beacon measurements. The obtained results are compared with the statistics calculated from measured rain attenuation and with the ITU recommendation model. As for fade duration, a good agreement with measurements has been found together with a significant improvement in terms of prediction errors with respect to the ITU‐R model. Synthetic storm technique is also able to predict fade slope statistics fairly well and has equivalent performance of ITU‐R model.     

An Infrastructure for Argumentative Agents

Multiagent systems are suitable for providing a framework that allows agents to perform collaborative processes in a social context. Furthermore, argumentation is a natural way of reaching agreements between several parties. However, it is difficult to find infrastructures of argumentation offering support for agent societies and their social context. Offering support for agent societies allows representation of more realistic environments to have argumentation dialogues. We propose an infrastructure to develop and execute argumentative agents in an open multiagent system. It offers tools to develop agents with argumentation capabilities. It also offers support for agent societies and their social context. The infrastructure is publicly available. Also, it has been implemented in an application scenario where argumentative agents try to reach an agreement about the best solution to solve a problem reported to the system.     

4D Biomaterials for Light‐Guided Angiogenesis

A strategy for spatial and temporal regulation of ligand presentation within a biomaterial, and the consequent site‐ and time‐specific cellular responses in 4D cell cultures are presented. The key molecular component is a light‐activatable adhesive peptidomimetic (cyclo Arg‐Gly‐Asp‐phe‐Cys, RGDfC) modified with the two‐photon photocleavable group (p‐methoxynitrobiphenyl, PMNB) used to functionalize a hydrogel. A scanning laser at 740 nm defines the 4D presentation of active RGD ligands within the gel, and directs basic cellular processes of embedded cells in situ. The excellent photochemical properties of the PMNB photoremovable group allows direct photomanipulation of the cellular environment without appreciable damage of the embedded cells. Light‐directed migration of fibroblasts within a crosslinked poly(ethylene glycol) (PEG) hydrogel, and sequential, light‐regulated angiogenesis with human umbilical vein endothelial cells (HUVECs) in 4D constructs is demonstrated. The materials presented here represent unique microenvironments to reconstruct dynamic changes in the composition of the extracellular space of cells that occur in in vivo tissues.     

Functionalization of poly(ε-caprolactone) by pendant hydroxyl, carboxylic acid and epoxide groups by atom transfer radical addition

A straightforward strategy is proposed for grafting hydroxyl, carboxylic acid and epoxide groups along poly(ε-caprolactone) chains. Statistical copolymerization of ε-caprolactone (εCL) with α-chloro-ε-caprolactone (αClεCL) has been initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP), followed by the atom transfer radical addition (ATRA) of but-3-en-1-ol, vinylacetic acid and 1,2-epoxyhex-5-ene, respectively, onto the α-chloro units of a poly(αClεCL-co-εCL) copolymer. αClεCL is easily prepared by the Baeyer-Villiger oxidation of 2-chlorocyclohexanone. The influence of the experimental conditions, i.e. temperature, solvent, catalyst, on the grafting yield has been discussed. Because ATRA is tolerant of the investigated functional groups, no protection/deprotection reaction is required, which is a major advantage of the method.