Pattern Matching for Sets of Segments

In this paper we present algorithms for a number of problems in geometric pattern matching where the input consists of a collection of orthogonal segments in the plane. Such collections arise naturally from problems in mapping buildings and robot exploration. We propose a new criterion for segment similarity called the coverage measure, and present efficient algorithms for maximizing it between sets of axis-parallel segments under translations. In the general case, we present a procedure running in time O(n³ log² n), and for the case when all segments are horizontal, we give a procedure that runs in time O(n² log² n). Here n is the number of segments. In addition, we show that an -approximation to the Hausdorff distance between two sets of horizontal segments under vertical translations can be computed in time O(n^3/2 max(poly(log M, log n, 1/))). Here, M denotes the ratio of the diameter to the closest pair of points in the sets of segments (where pairs of points lie on different segments). These algorithms are significant improvements over the general algorithm of Agarwal et al. that required time O(n⁴ log²     

Deblocking of block-transform compressed images using weighted sums of symmetrically aligned pixels.

A new class of related algorithms for deblocking block-transform compressed images and video sequences is proposed in this paper. The algorithms apply weighted sums on pixel quartets, which are symmetrically aligned with respect to block boundaries. The basic weights, which are aimed at very low bit-rate images, are obtained from a two-dimensional function which obeys predefined constraints. Using these weights on images compressed at higher bit rates produces a deblocked image which contains blurred "false" edges near real edges. We refer to this phenomenon as the ghosting effect. In order to prevent its occurrences, the weights of pixels, which belong to nonmonotone areas, are modified by dividing each pixel's weight by a predefined factor called a grade. This scheme is referred to as weight adaptation by grading (WABG). Better deblocking of monotone areas is achieved by applying three iterations of the WABG scheme on such areas followed by a fourth iteration which is applied on the rest of the image. We refer to this scheme as deblocking frames of variable size (DFOVS). DFOVS automatically adapts itself to the activity of each block. This new class of algorithms produces very good subjective results and PSNR results which are competitive relative to available state-of-the-art methods.     

0.45% saline and 5% dextrose in water, but not 0.9% saline or 5% dextrose in 0.9% saline, worsen brain edema two hours after closed head trauma in rats

In this study, we examined the effect of four i.v. fluids (250 mL/kg) on blood glucose and osmolality and brain tissue specific gravity after closed head trauma (CHT) in rats. CHT was delivered at Time 0; blood was sampled at 60 min; fluid infusion began at 75 min and ended at 105 min. Blood was again sampled at 105 and 120 min, and brain tissue specific gravity was determined at 120 min. Five groups (one control and four fluid-treated groups) received CHT, and five other groups (one control and four fluid-treated) did not (n = 9 in each group). 0.45% saline (1/2 NS) and 5% dextrose in water (D5W) accentuated the decrease of brain tissue specific gravity (1.0366 +/- 0.0025 and 1.0368 +/- 0.0028, respectively; mean +/- SD) caused by CHT (1.0395 +/- 0.0036), but 5% dextrose in 0.9% saline (D5NS) and 0.9% saline (NS) did not (1.0431 +/- 0.0042 and 1.0389 +/- 0.0049, respectively). In addition, 1/2 NS decreased blood osmolality (248 +/- 6 mOsm/L), D5W increased blood glucose (1095 +/- 173 mg/dL), D5NS increased blood osmolality (350 +/- 5 mOsm/L) and glucose (1695 +/- 76 mg/dL), and NS caused no significant change. We conclude that administering hypoosmolar i.v. fluids after CHT causes a significant worsening of cerebral edema 2 h after CHT. Implications: We previously reported worse neurological outcome and/or mortality after closed head trauma in rats when 5% dextrose in water or 0.45% saline was given i.v. compared with 0.9% saline or 5% dextrose in 0.9% saline. The present results and our previous findings indicate that worsening of outcome after closed head trauma in rats may be caused more by edema formation than by hyperglycemia.     

Symptomatic peritoneal calcification in a child: treatment with tidal peritoneal dialysis

OBJECTIVE: To evaluate the ability of tidal peritoneal dialysis to decrease the pain and frequency of hemoperitoneum associated with peritoneal calcification. DESIGN: Prospective case evaluation. SETTING: The Home Peritoneal Dialysis Unit, Children's Mercy Hospital. PATIENT: Seven-year old male with diffuse peritoneal calcifications, daily abdominal pain, and recurrent hemoperitoneum. INTERVENTION: Tidal peritoneal dialysis was conducted with an initial fill volume of 45 mL/kg and a tidal inflow volume of 23 mL/kg. The patient also maintained a daytime pass volume of 45 mL/kg. Duration of treatment was 7 months. RESULTS: The patient's abdominal pain resolved 2 days after initiating tidal peritoneal dialysis. No episodes of hemoperitoneum or abdominal pain have occurred for 7 months. CONCLUSION: Tidal peritoneal dialysis is a unique approach to the achievement of symptomatic relief in the patient with peritoneal calcification.     

The fifth transmembrane segment of the neuromedin B receptor is critical for high affinity neuromedin B binding

The two bombesin receptor subtypes, neuromedin B (NMB-R) and gastrin releasing peptide (GRP-R) receptors, bind their respective ligands with high affinity. To identify molecular components mediating high affinity NMB binding, four mutant receptors were constructed, in which different parts of the NMB-R were replaced with the corresponding regions of the GRP-R. When stably expressed in Balb 3T3 fibroblasts, all four NMB-R/GRP-R chimeras were functional and showed NMB-induced stimulation of inositol phosphate (IP) formation. Results of 125I-[D-Tyr0]NMB displacement assays using unlabeled NMB for competition indicated that high affinity NMB binding was determined by amino acid sequences in transmembrane domain V (TM-V) of the NMB-R. To identify which amino acid(s) in TM-V of NMB-R contributed to high affinity NMB binding, four additional NMB-R mutants were constructed where non-conserved amino acids in TM-V of NMB-R were replaced by the corresponding GRP-R amino acids. Three of the mutations, TyrPheLeu220-222-->PheTyrVal, Ile230-->Val, and His234-->Phe, did not affect high affinity NMB binding. The Ile216-->Ser substitution, however, abolished high affinity NMB binding and severely impaired the ability of the mutant receptor to stimulate NMB-dependent inositol phosphate formation. These results suggest that ILe216 in TM-V of NMB-R may be critical for high affinity NMB binding.     

Ticlopidine-induced thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) occurs in association with a wide variety of disorders including infections, connective tissue diseases, and solid organ tumors. It also may coincide with administration of drugs such as mitomycin, metronidazole, oral contraceptives, cyclosporine, and many others. We report the occurrence of TTP in a patient shortly after the initiation of ticlopidine.     

Organometallic polymers. V. Synthesis and properties of metallocene-modified polymers

The reaction of metallocenes with solutions of polydienes and halogenated polymers, under Friedel-Crafts conditions, has now been applied to the surface modification of solid polymer films. The reaction of ferrocene with chlorinated polyethylene films appears to proceed by a fast substitution step followed by a slower diffusion-controlled step. The stress–strain curves of surface-modified films, as well as of solution-cast polymetallocene films, have been examined by means of a bursting-strength apparatus. The weathering behavior of metallocene-modified polymers has been studied in both natural and accelerated conditions. Studies on the effect of ageing on composition and properties by spectrophotometric and mechanical measurements indicate that the photooxidative resistance of polymers is improved significantly by metallocene modification. Additionally, modified films have been found to be effective as clear shields for the protection of vulnerable substrates against photodegradation. The observed darkening of the irradiated films could be due to a thermal reaction between metallocene and photolytically generated macroperoxides.     

Interface characterization of InSb MOS structures

The electrical properties of MOS devices are critically dependent on the oxide-semiconductor interface. The preparation of suitable insulating layers of oxide or other material is essential for the performance of such devices and it is particularly difficult in the case of III-V compound semiconductors. We report a method of preparing an insulating layer on InSb by a plasma oxidation process. The oxidation method will be described as well as results of the analysis of the oxide-semiconductor interface by electrical and compositional techniques. Capacitance-voltage characteristics reveal the existence of interface states which are distributed near the conduction and the valence bands with a higher density near the former. Depth profiling of the oxide by Ar⁺ sputtering and Auger electron spectroscopy (AES) shows that the oxide is composed of a mixture of indium oxide with the antimony oxide. At the interface a transition region can clearly be observed, whose composition seems to be mostly indium oxide rich in metallic antimony. This information can be derived from the Auger line shapes and positions. We find AES to be an extremely helpful tool for this kind of investigation, in spite of the obvious disadvantages of ion sputtering, especially in the case of indium and antimony. Correlations of the AES data with the electrical analysis results are suggested.