First Measurement of the Nuclear-Recoil Ionization Yield in Silicon at 100 eV.

We measured the nuclear-recoil ionization yield in silicon with a cryogenic phonon-sensitive gram-scale detector. Neutrons from a monoenergetic beam scatter off of the silicon nuclei at angles corresponding to energy depositions from 4 keV down to 100 eV, the lowest energy probed so far. The results show no sign of an ionization production threshold above 100 eV. These results call for further investigation of the ionization yield theory and a comprehensive determination of the detector response function at energies below the keV scale.

Constraints on Lightly Ionizing Particles from CDMSlite.

The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to lightly ionizing particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically produced LIPs with an electric charge smaller than e/(3×10^{5}), as well as the strongest limits for charge ≤e/160, with a minimum vertical intensity of 1.36×10^{-7} cm^{-2} s^{-1} sr^{-1} at charge e/160. These results apply over a wide range of LIP masses (5 MeV/c^{2} to 100 TeV/c^{2}) and cover a wide range of ßγ values (0.1-10^{6}), thus excluding nonrelativistic LIPs with ßγ as small as 0.1 for the first time.

Light Dark Matter Search with a High-Resolution Athermal Phonon Detector Operated above Ground.

We present limits on spin-independent dark matter-nucleon interactions using a 10.6 g Si athermal phonon detector with a baseline energy resolution of σ_{E}=3.86±0.04(stat)_{-0.00}^{+0.19}(syst) eV. This exclusion analysis sets the most stringent dark matter-nucleon scattering cross-section limits achieved by a cryogenic detector for dark matter particle masses from 93 to 140 MeV/c^{2}, with a raw exposure of 9.9 g d acquired at an above-ground facility. This work illustrates the scientific potential of detectors with athermal phonon sensors with eV-scale energy resolution for future dark matter searches.

Triple Junction at the Triple Point Resolved on the Individual Particle Level.

At the triple point of a repulsive screened Coulomb system, a fcc crystal, a bcc crystal, and a fluid phase coexist. At their intersection, these three phases form a liquid groove, the triple junction. Using confocal microscopy, we resolve the triple junction on a single-particle level in a model system of charged PMMA colloids in a nonpolar solvent. The groove is found to be extremely deep and the incommensurate solid-solid interface to be very broad. Thermal fluctuations hence appear to dominate the solid-solid interface. This indicates a very low interfacial energy. The fcc-bcc interfacial energy is quantitatively determined based on Young's equation and, indeed, it is only about 1.3 times higher than the fcc-fluid interfacial energy close to the triple point.

Quasi-two-dimensional complex plasma containing spherical particles and their binary agglomerates.

A unique type of quasi-two-dimensional complex plasma system was observed which consisted of monodisperse microspheres and their binary agglomerations (dimers). The particles and their dimers levitated in a plasma sheath at slightly different heights and formed two distinct sublayers. The system did not crystallize and may be characterized as a disordered solid. The dimers were identified based on their characteristic appearance in defocused images, i.e., rotating interference fringe patterns. The in-plane and interplane particle separations exhibit nonmonotonic dependence on the discharge pressure.

Dust interferometers in plasmas.

An interferometric imaging technique has been proposed to instantly measure the diameter of individual spherical dust particles suspended in a gas discharge plasma. The technique is based on the defocused image analysis of both spherical particles and their binary agglomerates. Above a critical diameter, the defocused images of spherical particles contain stationary interference fringe patterns and the fringe number increases with particle diameters. Below this critical diameter, the particle size has been measured using the rotational interference fringe patterns which appear only on the defocused images of binary agglomerates. In this case, a lower cutoff limit of particle diameter has been predicted, below which no such rotational fringe patterns are observed for the binary agglomerates. The method can be useful as a diagnostics for complex plasma experiments on earth as well as under microgravity conditions.

Particle flows in a dc discharge in laboratory and microgravity conditions.

We describe a series of experiments on dust particles' flows in a positive column of a horizontal dc discharge operating in laboratory and microgravity conditions. The main observation is that the particle flow velocities in laboratory experiments are systematically higher than in microgravity experiments for otherwise identical discharge conditions. The paper provides an explanation for this interesting and unexpected observation. The explanation is based on a physical model, which properly takes into account main plasma-particle interaction mechanisms relevant to the described experimental study. A comparison of experimentally measured particle velocities and those calculated using the proposed model demonstrates reasonable agreement, both in laboratory and microgravity conditions, in the entire range of discharge parameters investigated.

Paget's disease of bone in a 85-year-old woman.

Paget's disease of bone is a rare disorder in India. Patients are usually asymptomatic and incidental radiological investigation invariably clinches the diagnosis. Increased alkaline phosphatase, X-ray, CT scan and scintiscan of bone can be done to confirm the diagnosis. Here we report a case of an 85-yr-old lady who had bilateral hearing loss for last 10 yrs, was admitted incidentally for some other complaints and on investigation diagnosed to have advanced Paget's disease of bone.

Superfluidlike motion of an absorbing body in a collisional plasma.

Motion of a small charged absorbing body (micrograin) immersed in a stationary weakly ionized high pressure plasma environment is considered. It is shown that the total frictional (drag) force acting on the grain can be directed along its motion, causing the grain acceleration. At some velocity, the forces associated with different plasma components can balance each other, allowing free undamped superfluid motion of the grain. The conditions when such behavior can be realized and the possibility of a superconductive grain current are discussed in the context of complex (dusty) plasmas.

Resection margin status in lumpectomy specimens for duct carcinoma of the breast: correlation with core biopsy and mammographic findings.

BACKGROUND: The strategy for surgical treatment of breast carcinoma proven by biopsy is mainly based on the physical and mammographic examinations. To investigate if the pathological findings in core biopsy are contributory to planning the surgical strategy, we correlated the status of ductal carcinoma in situ (DCIS) in the core needle biopsy of breast, the mammographic changes and the status of resection margins in the subsequent lumpectomy. STUDY DESIGN: Consecutive 130 core needle biopsies with prior mammography and subsequent lumpectomy were reviewed. Biopsies were divided into: group I, DCIS; group II, DCIS and infiltrating carcinoma (IC); and group III, IC. Mammographic findings were categorized into four groups: (a) nonspecific findings; (b) calcification (Ca(++)); Ca(++) and mass, and mass only. The status of margins in correlating lumpectomy specimens was reviewed. Close margin was defined as a free margin at less than 0.1cm from the carcinoma. RESULTS: The rates of positive or close margins in three groups I, II, and III were 13/18, 18/48, and 2/64 (P < 0.001); and in mammography groups of nonspecific finding, Ca(++), Ca(++) mass and mass only were 5/6, 7/15, 8/37, and 13/72 (P < 0.001), respectively. Of the total of 14 cases with positive margins of more than 0.5 cm in length, 8, 4, and 2 cases were from group I, II, and II, respectively. In addition, 13 of 21 cases with nonspecific changes or with only Ca(++) in mammograms belonged to the group I; 10 of these 13 cases were associated with positive margins. Forty-one of 72 cases presenting as a mass only in mammograms belonged to the group III; only 2 of these 41 cases were associated positive margins. CONCLUSIONS: Correlation of the extent of carcinoma with pre-operative histopathological findings was better than with mammography. Core biopsies containing only DCIS, particularly in cases with nonspecific findings or with only Ca(++) in mammograms, represent a group of breast carcinoma that pose the high risk for incomplete resection in lumpectomy. Surgical management of patients having these cores includes wider resection margins than would otherwise be taken. Most core biopsies with only IC were associated with negative margins.

Cloning and characterization of a novel serine/threonine protein phosphatase type 5 from Trypanosoma brucei.

Reversible protein phosphorylation is essential for the regulation of numerous cellular functions and differentiation. The haemo-flagellated parasitic protozoan Trypanosoma brucei, the causative agent for African trypanosomiasis undergoes various stages of cellular differentiation during its digenetic life cycle. A complete cDNA of a unique serine/threonine phosphatase type five (TbPP5) was cloned and characterized from T. brucei. TbPP5 contains an open reading frame of 1416 bp that encodes a protein of about 53 kDa and exists as a single copy gene in the T. brucei genome. The deduced amino acid sequence showed 45-48% overall identity and 60-65% similarity with protein phosphatase 5's (PP5) from different species. Analysis of the primary sequence revealed that TbPP5 contains three TPR motifs at the N-terminal region (amino acid residues 7-107) while the phosphatase catalytic domain occurs in the C-terminal region (amino acid residues 210-410). A TbPP5 cDNA hybridized with a transcript of 2.5 kb which is present at similar levels in the procyclic and the bloodstream forms. However, the level of expression of the TbPP5 protein (52 kDa) detected by an antibody developed against a recombinant protein produced in E. coli was about 2-fold higher in the procyclic than the bloodstream form. The TbPP5 transcript level gradually decreased in cells grown in the logarithmic phase to the stationary phase in culture. Moreover, 18 h serum starvation of the procyclic forms decreased the level of the specific transcript about 3-fold suggesting that this protein may play a role during the active growth phase of the organism. The recombinant protein showed phosphatase activity which was stimulated about 2.6-fold by arachidonic acid with half-maximal activity at 75 microM. Indirect immuno-fluorescence of permeabilized cells revealed that the protein is localized in the cytosol and the nucleus This is the first report for the identification of a type 5 serine/threonine protein phosphatase in an ancient eukaryote such as T. brucei.

Analysis of in vitro activities of herpes simplex virus type 1 UL42 mutant proteins: correlation with in vivo function.

The DNA polymerase (pol) catalytic subunit of herpes simplex virus type 1, encoded by UL30, and its accessory factor, UL42 protein, are both essential for the replication of the virus. Because the stable interaction between UL42 and pol renders the pol fully processive for replicative DNA synthesis, disruption of this interaction represents a potential goal in the development of novel antiviral compounds. To better compare the effects of mutations in UL42 protein on its known in vitro functions, mutations were expressed as glutathione-S-transferase (GST)-fusions and the fusion proteins used in affinity chromatography. In this report, we demonstrate the relationship between the abilities of mutant UL42 fusion proteins to bind pol and to stimulate pol activity in vitro, and the abilities of nonfusion mutant proteins to function in viral replication. The pol stimulation assay using GST fusion proteins was found to be a more accurate and sensitive measure of the ability of the UL42 protein to function in vitro than the pol binding assay using the fusion proteins linked to a solid matrix. We also found an excellent correlation between the ability of purified GST fusion proteins to stimulate pol activity in vitro and the ability of full-length nonfusion UL42 mutant genes to support DNA replication in infected cells. Our results demonstrate that two noncontiguous stretches of amino acids, from 137 to 142 and from 274 to 282, are essential for UL42 function in vivo and in vitro. Although mutant d241-261 exhibited close to wild-type abilities to stimulate pol activity in vitro, it was not capable of complementing the replication of a UL42 null mutant virus. The region of UL42 protein within or close to 241-261 may serve to hinge the essential regions within the N- and C-terminal portions of the protein which are thought to interdigitate. It is hypothesized that reduction in the length of the hinge region could alter the ability of UL42, and/or its complex with pol, to function with one or more of the other proteins present in the DNA replisome within infected cells.

Biochemical and molecular properties of the Trypanosoma brucei alternative oxidase.

The protozoal parasite Trypanosoma brucei depends on a mitochondrial non-cytochrome terminal oxidase known as the trypanosome alternative oxidase (TAO) in its mammalian host. We have recently cloned the cDNA from T. brucei bloodstream form and have characterized a 33 kDa mitochondrial protein as TAO. Here we report that the TAO is a single copy gene in T. brucei and its expression is down regulated at the level of transcript abundance during differentiation from the bloodstream to the procyclic trypanosomes. Like other alternative oxidases (AOXs) cloned from different plants and fungi, TAO possesses the conserved sequences at the centrally located predicted membrane spanning domains and the signature sequence at the C-terminal hydrophilic domain for a pair of putative iron binding motifs (E-X-X-H). Phylogenetic analysis of the deduced protein sequences of eight different alternative oxidases cloned from different plants and fungi revealed that TAO is more closely related to the alternative oxidases of the fungi clade than that of plants. TAO has been functionally expressed in Escherichia coli. In the first of the two putative iron binding motifs, site-directed mutagenesis of E215 to A, L, N and Q resulted in the loss of the ability of the TAO gene to complement the heme deficiency of the E. coli mutants (SASX41B and GE1387) by conferring on them a CN-insensitive pathway of respiration. The conservative substitution of E215 by aspartate and histidine reduced the growth of the E. coli auxotrophs by approximately 80%. The mutations apparently did not have any effect on the stability of the expressed protein as revealed by the immunoblot analysis of the bacterial protein using TAO monoclonal antibody, which we have developed. Together, these points suggest that E215 plays an important role in the function of TAO. The steady state level of TAO mRNA is down-regulated in the procyclic stage presumably accounting for the low levels of TAO protein in these forms.

A clinicobacteriological study on leucorrhoea.

The pathogens like Trichomonas vaginalis (4.5%), N gonorrhoeae (2.7%) and C albicans (6.7%) were exclusively present in leucorrhoea. The other potential agents with their respective percentages in normal women and cases of leucorrhoea were U urealyticum (21.2% and 50.2%), actinomyces (29.7% and 41.6%), Chlamydia trachomatis (17% and 48.8%), candida-like organisms (CLO) (1.2% and 9.5%) and non-group B streptococci (4.2% and 16.7%). The percentages of urethral syndrome (65.8%), vaginal irritation (63.4%), sore vulva (17%), cervicitis (13.4%), cervical erosion (11%) of the STD clinic were more than those of gynaecological cases. The latter group more often revealed infertility (15.8%) and pelvic inflammatory disease (13.6%). The exclusive isolation rate of N gonorrhoeae (7.3%) and prevalence of G vaginalis (19.5%) and Trichomonas vaginalis (8.5%) in the STD clinic were notable. The cases of gynaecological clinic more commonly showed C albicans (8%) and CLO (13.6%). Significant differences pertaining to U urealyticum (leucorrhoea and inapparent group p < 0.01; leucorrhoea and normal cases p < 0.01), M hominis (leucorrhoea and inapparent group p < 0.05; leucorrhoea and normal cases p < 0.01), Chlamydia trachomatis (leucorrhoea and normal cases p < 0.01) and also actinomyces (leucorrhoea and normal cases p < 0.01; inapparent and normal cases p < 0.05) were recorded. There was conspicuous association of U urealyticum, M hominis, G vaginalis, Chlamydia trachomatis, CLO and actinomyces with leucorrhoea. An almost exclusive presence of Staph aureus, Esch coli and Klebsiella in cases of leucorrhoea appeared meaningful.

Acute upper gastrointestinal hemorrhage in older people: a prospective study in two neighboring districts.

OBJECTIVE: To study the distribution of mucosal lesions and outcomes in older people with acute upper gastrointestinal hemorrhage (UGIH). DESIGN: Prospective case study. SETTING: Two neighboring district hospitals with similar admission policies. SUBJECTS: Consecutive patients aged 75 years or older admitted with hematemesis and/or melena during the study period. OUTCOME MEASURES: Length of hospital stay, mortality, surgical intervention, and transfusion requirements. RESULTS: A total of 109 patients were entered into the study. Of these, 106 (97%) underwent gastroscopy, and bleeding sites were identified in 98%. Upper gut malignancies were identified in eight patients, ulcerative esophagitis in 32, benign gastric ulcers in 24, and duodenal ulcers in 23 patients. Forty-seven percent had severe anemia on admission (Hb < 10 g/dL). Thirty-eight patients were referred for surgery, and eight were operated on, with one postoperative death. Six other patients died, five of whom had malignancies. The overall mortality of 6% reduced to 2% if those with malignancy were excluded. The 92 patients discharged had a median hospital stay of 15 days (range 2-30). CONCLUSIONS: Older people with acute UGIH have advanced upper gut pathology with preponderance of esophageal lesions. Classical symptoms seem lacking, but mortality can be decreased despite adverse comorbid factors. Lower thresholds for endoscopy are advocated in older adults, and comparative studies of UGIH symptoms with younger patients are required.

Small for gestational age babies: Indian scene.

Intrauterine growth retardation (IUGR) is an important determinant of neonatal mortality, morbidity and poor neurologic outcome. The study was aimed to evaluate the magnitude of perinatal risk factors in causation and the neonatal outcome of small for gestational age (SGA) babies. One hundred and three SGA babies born over a period of one year were retrospectively analysed during their hospital stay. 3.53 per cent of the babies were SGA with mean birth weight of 1657 +/- SD 354 gm (range 600-2200 gm). 68.9 per cent were term babies and 51.5 per cent were females. Toxemia of pregnancy (30.09%), hypertensive diseases of pregnancy (HDP) excluding toxemia (5.8%), diabetes mellitus (1.94%), medical disorders including renal and cardiac (3.88%), anemia (Hb < 8 gm%) and IU infection (0.97%) were the main conditions responsible for SGA. In 56.3% pregnancies, no cause could be ascertained. The common perinatal problems were infections in 27 (26.2%), birth asphyxia in 22 (21.36%), polycythemia in 25 (24.3%), jaundice in 22 (21.36%) and hypoglycemia in 7 (6.8%). Congenital malformations in 2 (1.94%) and Hyaline membrane disease in 1 (0.97%) were uncommon problems. 5.8 per cent babies died due to various perinatal problems. Based on these findings it was concluded that idiopathic (? Constitutional) intrauterine growth retardation was the commonest cause of SGA in Indian babies. 58.3 per cent babies had neonatal problems and they had a better survival compared to their western counterparts.

Kinetics of theophylline in apnea of prematurity in small for gestational age babies.

OBJECTIVES: To study the pharmacokinetics of theophylline and its correlations to pharmacodynamic effects in apnea of prematurity in small for gestational age babies. DESIGN: Prospective case control study. SETTING: Level III Neonatal Intensive Care Unit. SUBJECTS: Ten small for gestational age (SGA) babies and 10 gestation matched appropriate for gestational age (AGA) babies with recurrent apnea of prematurity. METHODS: All babies were investigated to exclude secondary causes of apnea. 5 mg/kg of aminophylline loading dose followed by 2 mg/kg as maintenance dose every 8 hourly intravenously was used. The trough and peak levels of theophylline were assessed on different days of therapy. Clinical monitoring was done for the efficacy and toxicity of the drug. Analysis was done using unpaired Student's 't' test and the correlation between plasma theophylline levels of different days was performed by using ANOVA. RESULTS: The therapeutic drug levels were achieved within 24 hours in all babies. The SGA babies showed 25% higher drug levels as compared to AGA babies. The mean trough plasma theophylline levels ranged from 8.15 +/- 1.59 to 12.37 +/- 1.54 micrograms/ml in SGA babies while in AGA babies they ranged from 6.26 +/- 1.93 to 9.96 +/- 1.96 micrograms/ml in first 8 days of therapy. The mean peak levels in SGA babies ranged from 11.91 +/- 1.84 to 17.13 +/- 1.63 micrograms/ml and in AGA babies ranged from 8.17 +/- 1.84 to 13.02 +/- 1.48 micrograms/ml. Twenty per cent SGA and AGA babies each developed clinical toxicity though toxic drug levels were found in 50% SGA and 30% AGA babies. CONCLUSION: There is a need to modify dosage schedule for these babies.