4-bit adder-accumulator at 41-GHz clock frequency in InP DHBT technology

A 41-GHz 4-b adder-accumulator test circuit implemented in InP double heterojunction bipolar transistor (DHBT) technology using 624 transistors is reported. High clock rates are obtained by combining the logic functions into pipelined latches. The adder-accumulator contains a single-level parallel-gated carry circuit that is used as a step toward reduced power consumption. The carry circuit has a maximum clock frequency of 55 GHz. The accumulator architecture employs modular, pipelined 2-b adders and is cascadable to 2 N-bits. The test circuit includes a 4-b digital to analog converter (DAC) that facilitates demonstration of high-speed operation.     

Pre-Attentive and Attentive Detection of Humans in Wide-Field Scenes

We address the problem of localizing and obtaining high-resolution footage of the people present in a scene. We propose a biologically-inspired solution combining pre-attentive, low-resolution sensing for detection with shiftable, high-resolution, attentive sensing for confirmation and further analysis. The detection problem is made difficult by the unconstrained nature of realistic environments and human behaviour, and the low resolution of pre-attentive sensing. Analysis of human peripheral vision suggests a solution based on integration of relatively simple but complementary cues. We develop a Bayesian approach involving layered probabilistic modeling and spatial integration using a flexible norm that maximizes the statistical power of both dense and sparse cues. We compare the statistical power of several cues and demonstrate the advantage of cue integration. We evaluate the Bayesian cue integration method for human detection on a labelled surveillance database and find that it outperforms several competing methods based on conjunctive combinations of classifiers (e.g., Adaboost). We have developed a real-time version of our pre-attentive human activity sensor that generates saccadic targets for an attentive foveated vision system. Output from high-resolution attentive detection algorithms and gaze state parameters are fed back as statistical priors and combined with pre-attentive cues to determine saccadic behaviour. The result is a closed-loop system that fixates faces over a 130 deg field of view, allowing high-resolution capture of facial video over a large dynamic scene.     

Dysplastic nevi and other risk markers for melanoma

Risk markers for cancer are genetic or behavioral attributes that are statistically associated with increased incidence of cancer. Risk may be assessed either in case-control studies, or in cohort studies in which individuals with particular attributes are followed and cancer risk is determined by direct observation. Both of these methods have been used to determine the major risk markers for melanoma. The single most important risk marker is the presence on the skin of dysplastic nevi. Dysplastic nevi may be regarded as intermediate lesions of tumor progression, in that approximately 30% of melanomas arise in association with a precursor nevus, which is most commonly dysplastic. However, paradoxically, because they are vastly more numerous than melanoma, most dysplastic nevi are stable lesions that do not progress. Additional important melanoma risk factors include a family and/or personal history of melanoma. A third major category of risk markers includes indicators of acute and chronic exposure to the sun, including freckles, actinic skin damage, and a history of sunburn. Evaluation of these markers in oncological patients and their first-degree relatives can identify a population of individuals whose risk for melanoma ranges from several-fold to more than 100-fold greater than that of random population members. Efforts directed at early diagnosis in these individuals can result in recognition of melanomas in their early, curable stages.     

Inversin, a novel gene in the vertebrate left-right axis pathway, is partially deleted in the inv mouse

A DNA fragment containing the recA gene of Gluconobacter oxydans was isolated and further characterized for its nucleotide sequence and ability to functionally complement various recA mutations. When expressed in an Escherichia coli recA host, the G. oxydans recA protein could efficiently function in homologous recombination and DNA damage repair. The recA gene's nucleotide sequence analysis revealed a protein of 344 amino acids with a molecular mass of 38 kDa. We observed an E. coli-like LexA repressor-binding site in the G. oxydans recA gene promoter region, suggesting that a LexA-like mediated response system may exist in G. oxydans. The expression of G. oxydans recA in E. coli RR1, a recA+ strain, surprisingly caused a remarkable reduction of the host wild-type recA gene function, whereas the expression of both Serratia marcescens recA and Pseudomonas aeruginosa recA gene caused only a slight inhibitory effect on function of the host wild-type recA gene product. Compared with the E. coli RecA protein, the identity of the amino acid sequence of G. oxydans RecA protein is much lower than those RecA proteins of both S. marcescens and Pseudomonas aeruginosa. This result suggests that the expression of another wild-type RecA could interfere with host wild-type recA gene's function, and the extent of such an interference is possibly correlated to the identity of the amino acid sequence between the two classes of RecA protein.     

Concerted evolution at the population level: pupfish HindIII satellite DNA sequences

The canonical monomers (approximately 170 bp) of an abundant (1.9 x 10(6) copies per diploid genome) satellite DNA sequence family in the genome of Cyprinodon variegatus, a "pupfish" that ranges along the Atlantic coast from Cape Cod to central Mexico, are divergent in base sequence in 10 of 12 samples collected from natural populations. The divergence involves substitutions, deletions, and insertions, is marked in scope (mean pairwise sequence similarity = 61.6%; range = 35-95.9%), is largely confined to the 3' half of the monomer, and is not correlated with the distance among collecting sites. Repetitive cloning and direct genomic sequencing experiments failed to detect intrapopulation and intraindividual variation, suggesting high levels of sequence homogeneity within populations. The satellite sequence has therefore undergone "concerted evolution," at the level of the local population. Concerted evolution has previously almost always been discussed in terms of the divergence of species or higher taxa; its intraspecific occurrence apparently has not been reported previously. The generality of the observation is difficult to evaluate, for although satellite DNAs from a large number of organisms have been studied in detail, there appear to be little or no other data on their sequence variation in natural populations. The relationship (if any) between concerted, population level, satellite DNA divergence and the extent of gene flow/genetic isolation among conspecific natural populations remains to be established.     

Transport of the dicyanogold(i) anion

We have shown that dicyanogold(I), [Au(CN)(2)](-) is a common metabolite found in blood and urine samples of patients treated with different gold based drugs. Some patients have high levels of gold within their red blood cells (RBCs). Size exclusion and C18 reversed phase chromatography show that the majority of the gold in RBC lysates is bound to protein, but small molecules such as dicyanogold(I) and gold-glutathione complexes are also present. Dicyanogold incubation with red blood cells in vitro leads to a rapid and complete uptake of gold. This uptake is unaffected by DIDS, an inhibitor of the anion channel, but is blocked by the addition of external cyanide. Dicyanogold is also readily taken up by H9 cells, a continuous CD(4+) cell line. This uptake is significantly inhibited by N-ethylmaleimide, suggesting a requirement for sulfhydryl groups. Dicyanogold inhibits the replication of the AIDS virus, HIV, in a cell culture model.     

Hierarchical Classifiers for Robust Topological Robot Localization

This paper presents a novel appearance-based technique for topological robot localization and place recognition. A vocabulary of visual words is formed automatically, representing local features that frequently occur in the set of training images. Using the vocabulary, a spatial pyramid representation is built for each image by repeatedly subdividing it and computing histograms of visual words at increasingly fine resolutions. An information maximization technique is then applied to build a hierarchical classifier for each class by learning informative features. While top-level features in the hierarchy are selected from the coarsest resolution of the representation, capturing the holistic statistical properties of the images, child features are selected from finer resolutions, encoding more local characteristics, redundant with the information coded by their parents. Exploiting the redundancy in the data enables the localization system to achieve greater reliability against dynamic variations in the environment. Achieving an average classification accuracy of 88.9% on a challenging topological localization database, consisting of twenty seven outdoor places, demonstrates the advantages of our hierarchical framework for dealing with dynamic variations that cannot be learned during training.     

Synthesis in vitro of intrinsic membrane proteins by free, membrane-bound, and Golgi apparatus-associated polyribosomes from rat liver

A fraction of intrinsic membrane proteins was prepared from the major membranous cell components of rat liver by extraction of the membranes with KCl and deoxycholate. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the compositions of the intrinsic protein fractions from rough and endoplasmic reticulum, smooth endoplasmic reticulum. Golgi apparatus, plasma membrane, and nuclear envelope were similar to each other but distinct from that of mitochondria. Among endomembranes, differences were in the ratios of protein constituents plus a few protein bands of Golgi apparatus and plasma membranes not found in endoplasmic reticulum or nuclear envelope. The abilities of total rough endoplasmic reticulum, polysomes released from rough endoplasmic reticulum, and free polysomes to incorporate amino acids into the intrinsic protein fraction were tested in vitro. Polysomes bound to endoplasmic reticulum has the greatest capacity to synthesize proteins of this fraction as shown by co-purification of radioactive products and by immunoprecipitation. Although the majority of the radioactive products synthesized by bound polysomes were distinct from those synthesized by free polysomes, certain radioactive products synthesized by free polysomes also co-purified with intrinsic membrane proteins. The results show no absolute segregation between free and bound polysomes in the synthesis of intrinsic membrane proteins. However, the majority of these proteins appear to be synthesized by polysomes bound to the endoplasmic reticulum. Several intrinsic proteins found in plasma membranes do not appear in rough endoplasmic reticulum. To determine where these proteins were synthesized, the ability of other endomembrane components to support in vitro incorporation of [14C]leucine into protein was examined. In contrast to plasma membranes, isolated Golgi apparatus fractions did incorporate [14C]leucine to an extent greater than could be explained by contamination with rough endoplasmic reticulum. Golgi apparatus in situ and isolated from rat liver have polyribosomes associated with a zone of cytoplasm at the Golgi apparatus periphery occupied by tubules and vesicles. The polysomes are not directly attached to membranes as with rough endoplasmic reticulum and may represent a special class of "Golgi apparatus-associated" polysomes. The polysomes, when associated with Golgi apparatus membranes, incorporated amino acids in vitro. The products synthesized in vitro were analyzed by treatment with KCl and deoxycholate and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Certain proteins synthesized by the Golgi apparatus-associated polysomes remained insoluble after the treatment with KCl and deoxycholate. The proteins synthesized by the Golgi apparatus fraction had mobilities similar to proteins in plasma membranes which were absent from endoplasmic reticulum, and which were relatively minor components of Golgi apparatus...     

Investigation of optical clearing of gastric tissue immersed with hyperosmotic agents

In order to understand the role of water desorption and the mass transport process in the optical clearing effect on gastric tissues with the application of hyperosmotic agents, the porcine stomach tissues (pyloric mucosa) applied topically with glycerol and dimethyl sulfoxide (DMSO) are investigated with optical coherence tomography (OCT) and the near infrared reflectance spectroscopy. Three solutions of 80% and 50% glycerol, and 50% DMSO are studied, each of which shows significant improvement in light transmittance and, thus, reduction of the light scattering of tissue. It is found that, among the solutions investigated, 80% glycerol achieves the best clearing effect on improvement of both the light penetration and imaging contrast. More detailed microstructures of the mucosal layer can be observed for glycerol treatment, while these structures are not resolvable by the conventional OCT. Light transmittance is increased by approximately 23% and diffuse reflectance decreased by approximately 24% at 30 min after the topical application of 80% glycerol. 50% DMSO is more effective than 50% glycerol only at the beginning stage; thereafter the rate of optical clearing is slowed down with time. Although DMSO can enhance the light transmittance and thus reduce the scattering, it has a negligible effect on the imaging contrast improvement. The mass transport process of agent to tissue accounts for the different clearing effects for glycerol and DMSO, respectively. It is concluded that the optical clearing by the hyperosmotic agent is strongly correlated with the water desorption kinetics induced by agent and the agent mass transport process within tissue. In other words, the tissue dehydration induced by agent and the refractive index matching between the agent and the main scattering components within tissue facilitated by the agent mass transport are responsible for optical clearing effects.     

The Use of Surface Analysis Techniques to Determine the Route of Manufacture of Tablet Dosage Forms

ABSTRACT

Analytical methods for determining the manufacturing process of tablet dosage forms have not been previously reported. The use of surface analysis techniques in particular X-ray Photoelectron Spectroscopy and Time of Flight Secondary Ionization Mass Spectrometry will be described and a model proposed which allows the prediction of the route of manufacture in calcium phosphate and cellulosic-based tablet formulations. Results of the application of this model to evaluate prototype tablet formulations prepared by wet granulation or direct compression will be reported. Strengths and limitations of the model will be discussed.