Types Ic Research Articles

Dislocation electrical conductivity of synthetic diamond films

A relationship between the electric resistance of single-crystal homoepitaxial and polycrystalline diamond films and their internal structure has been investigated. It is established that the electrical conductivity of undoped homoepitaxial and polycrystalline diamond films is directly related to the dislocation density in them. A relation linking the resistivity ρ (∼1013–1015 Ω cm) with the dislocation density Γ (∼1014−4 × 1016 m−2) is obtained. The character of this correlation is similar for both groups of homoepitaxial and polycrystalline diamond films. Thin (∼1–8 μm) homoepitaxial and polycrystalline diamond films with small-angle dislocation boundaries between mosaic blocks exhibit dislocation conductivity. The activation energy of dislocation acceptor centers was calculated from the temperature dependence of the conductivity and was found to be ∼0.3 eV. The conduction of thick diamond films (h > 10 μm) with the resistivity ρ ≈ 108 Ω cm is determined by the conduction of intercrystallite boundaries, which have a nondiamond hydrogenated structure. The electronic properties of the diamond films are compared with those of natural semiconductor diamonds of types IIb and Ic, in which dislocation acceptor centers have activation energies in the range 0.2–0.35 eV and are responsible for hole conduction.

Forensic application of Epstein-Barr virus genotype: Correlation between viral genotype and geographical area

Using 50 forensic blood samples, the latent membrane protein 2A (LMP-2A) gene of Epstein-Barr virus (EBV) DNA was amplified to find a geographic correlation among the EBV genotypes. EBV DNA was detected in nine samples. From a phylogenetic analysis using 18 reported sequences as a reference, six EBV subtypes (Ia, Ib, Ic IIa, IIb, and IIc) were found. Japanese isolates were included in subtypes Ia or IIa. All the Asian reference isolates, except isolate D6, were included in subtype Ia or IIa. Mediterranean, an Alaskan and other African isolates were included in types Ib, Ic, IIb and IIc. The EBV genotype in the LMP-2A gene was thus demonstrated as being correlated with the host's geographical location. Typing in the EBV-associated nuclear antigen 2 gene was not related to that in the LMP-2A gene. Detection of the EBV genotype in the LMP-2A gene may be useful for determining the geographical origins of unidentified cadavers.

Absolute Magnitude Distributions and Light Curves of Stripped-Envelope Supernovae

The absolute visual magnitudes of three Type IIb, 11 Type Ib, and 13 Type Ic supernovae (collectively known as stripped-envelope supernovae) are studied by collecting data on the apparent magnitude, distance, and interstellar extinction of each event. Weighted and unweighted mean absolute magnitudes of the combined sample, as well as various subsets of the sample, are reported. The limited sample size and the considerable uncertainties, especially those associated with extinction in the host galaxies, prevent firm conclusions regarding differences between the absolute magnitudes of supernovae of Types Ib and Ic, and regarding the existence of separate groups of overluminous and normal-luminosity stripped-envelope supernovae. The spectroscopic characteristics of the events of the sample are considered. Three of the four overluminous events are known to have had unusual spectra. Most but not all of the normal-luminosity events have had typical spectra. The light curves of stripped-envelope supernovae are collected and compared. Because SN 1994I in M51 was very well observed, it often is regarded as the prototypical Type Ic supernova, but it has the fastest light curve in the sample. Light curves are modeled by means of a simple analytical technique that, combined with a constraint on E/M from spectroscopy, yields internally consistent values of ejected mass, kinetic energy, and nickel mass.

Genetics of Pseudohypoparathyroidism Types Ia and Ic

Pseudohypoparathyroidism (PHP) types Ia and Ic result from heterozygous inactivating mutations of Gs alpha, the alpha-subunit of the heterotrimeric stimulatory G-protein, Gs. Both are characterized by a combination of Albright's hereditary osteodystrophy and, when the mutation is maternally inherited, end-organ resistance to multiple hormones. Due to complex tissue-specific imprinting of Gs alpha, paternally-derived mutations do not usually lead to hormone resistance. More than 100 mutations have been characterized in patients with PHP-Ia and one mutation in type Ic. These are scattered throughout the gene, with one significant mutational hotspot in exon 7. Identification of mutations in a clinical service setting is important for accurate genetic counselling and clinical management of affected families. However, only 70-80% of mutations are identified by direct sequencing of coding exons and splice junctions. Screening for whole exon deletions and intronic or regulatory mutations in mutation-negative families is therefore now an important priority to establish the full mutational spectrum in these conditions.

Classification of congenital biliary cystic disease: special reference to type Ic and IVA cysts with primary ductal stricture

Congenital biliary cysts occur not only in the choledochus but also everywhere in the biliary tree, and are frequently accompanied by pancreatobiliary malunion. Alonso-Lej and colleagues first classified choledochal cysts into three types, in 1959. Due to the recognition of intrahepatic involvement, we refined their classification into six types, in 1977, and this has become the reference. However, this classification does not include the concept of pancreatobiliary malunion and has caused some confusion, especially in regard to types Ic and IVA. Type Ic, showing fusiform dilatation, has a pancreatobiliary malunion and often extends continuously to the intrahepatic duct. Type IVA, with intrahepatic involvement, shows primary ductal stricture, especially around the hepatic hilum and umbilicus. The incidence of the stricture is considerably greater than was previously assumed, and upstream intrahepatic ducts often join the dilated duct, with distinct caliber change. Intrahepatic dilatation may develop primarily, due to the stricture, combined with weakness of the duct wall. This stricture can be corrected by portal dissection in the liver to obtain a large anastomosis. In patients with intrahepatic involvement, we should carefully find the stricture by suitable cholangiograms, or by intraoperative cholangioscopy. Detecting the ductal stricture is obviously important, rather than classifying the cyst as type Ic or IVA.

Multi-photon microscopy of cell types in the viable taste disk of the frog.

The morphology of viable taste disks of the frog was explored with multi-photon microscopy. In order to identify single sensory or supporting cells within the tissue, we searched for fluorescent dyes that stained subsets of the cell population or possibly cell types. Some cell types indeed stained preferentially with certain fluorescent dyes. A subset of glia-like cells (type Ic) stained with BCECF, a H+-sensitive dye, and indo-1, a Ca2+-sensitive dye, both presented in the membrane-permeant ester form. BCECF-ester also stained the dendrites of type III receptor cells, but indo-1 ester did not. Receptor cells of type II stained with MQAE, a positively charged Cl- -sensitive dye. A subset of type II cells accumulated amiloride, a positively charged fluorescent diuretic. Certain supporting cells, i.e., wing cells (type Ib) and glia-like cells (type Ic), were labeled by negatively charged dyes, e.g., calcium green-1 dextran. Mucus cells (type Ia) were stained with only two of the 19 dyes examined, and Merkel-like basal cells (type IV) were stained only with a membrane-labeling voltage-sensitive dye, presumably by endocytosis. No dye was found which would stain all types of cells or all receptor cells. This finding reveals a potential problem for future functional imaging aiming at population responses, as the responses of unstained cells then would remain unobserved. Specificity of dyes with respect to cell types was sufficient to identify supporting cells and receptor cells. Cell shape could then be reconstructed, using optical slicing and rendering techniques. Thus populations of dye-loaded elongated cells, especially types Ic, II and III, could for the first time be visualized in three dimensions.

Albright's hereditary osteodystrophy and pseudohypoparathyroidism.

Pseudohypoparathyroidism (PHP) and Albright's hereditary osteodystrophy (AHO) are not interchangeable terms. AHO describes a constellation of physical features, including short adult stature, obesity, brachydactyly, and ectopic ossifications. PHP means end-organ resistance to PTH and is subclassified into types Ia, Ib, and Ic and type II. Pseudopseudohypoparathyroidism (PPHP) is a term used for individuals with AHO who have normal end-organ responses to PTH. Both the PHPIa and PPHP forms of AHO result from heterozygous deactivating mutations in the GNAS1 gene associated with a 50% reduction in bioactivity of the Gsalpha protein that it encodes. The GNAS1 gene is subject to tissue-specific genomic imprinting. Patients with mutations on their maternally derived allele are likely to have associated PHPIa, whereas mutations on the paternal allele usually cause PPHP. Isolated PTH resistance (PHPIb) can result from mutations within the GNAS1 gene but is more commonly caused by epigenetic imprinting abnormalities affecting the upstream exon 1A. The causes of PHP type Ic and PHP type II are not yet clear, and the latter is likely to be heterogeneous.

Odontoblast Dysfunction in Osteogenesis Imperfecta: An LM, SEM, and Ultrastructural Study

The inherited dentin defect dentinogenesis imperfecta (DI), while clinically obvious in osteogenesis imperfecta (OI) Types IB and IC, II, III, and IVB, is now thought to be present in all children with OI, in a continuum from minimal to severe dentin pathology. This collaborative study further clarifies the structural and ultrastructural dentin changes in the teeth of OI children with clinically obvious DI, and attempts to explain these in terms of odontoblast dysfunction. Collaborative studies were carried out in Melbourne, Australia, and Strasbourg, France, using light and polarized-light microscopy, scanning and transmission electron microscopy (SEM, TEM), selected-area diffraction (SAD), and x-ray spectroscopy (EDX). These showed structurally normal enamel (but containing long and broad lamellae) and a normally scalloped dentino-enamel junction (DEJ), but severe pathologic changes in the dentin. An initial narrow band of normal-appearing dentin tubules (including the mantle layer) ceased abruptly and was replaced by a wavelike laminar zone parallel to the DEJ with occluded tubules. Multiple parallel channels of 5-10 w m diameter were present at right angles to the DEJ indenting this zone, some terminating in retro-curved "processes." The abnormal dentin containing these channels almost completely occluded the pulp chamber. The structural and ultrastructural changes seen can be explained on the basis of the collagen defect in OI resulting in odontoblast dysfunction, which produces a distinct phenotype and one that is different from that in bone.

Spectral characteristics of fluorescence probes based on pyrene in solution and in polymer matrix

Spectral properties of four types of bifunctional probes based on pyrene and sterically hindered amines (HAS) were compared in solution of cyclohexane and methanol and in polymer matrices as isotactic polypropylene (iPP), polystyrene (PS), poly(methyl methacrylate) (PMMA) and poly(vinyl chloride) (PVC). Absorption spectra of these probes strongly depend on the type of linkage. When the carbonyl group in the linkage is in α-position to pyrene ring, the absorption bands are broader with rather poor vibrational resolution. The carbonyl group in α-position influences the emission spectra as well. For derivatives of 4-oxo-4-(1-pyrene)butanoic acid (I), the broad emission band was observed. Some vibrational resolution was observed for probes based on 1-pyrenecarboxylic acid (IV). Lifetime of these probes is in the range 1–10 ns. When methylene group instead of carbonyl is attached to pyrene and forms the link, the absorption spectra are the same as that of alkyl-substituted pyrene. This behaviour was shown for derivatives of 1-pyreneacetic acid (III) and 4-(1-pyrene)butyric acid (II). The emission spectra of these probes are similar as parent alkyl pyrene. The lifetime is in the range above 100 ns. The influence of solvent polarity and polymer matrix on spectra was not very pronounced for probe of parent amine types Ic–IVc. The decay of fluorescence of probes of this type was satisfactorily fitted to monoexponential function. The efficiency of intramolecular quenching observed for oxidised probes Id–IVd is in the range from about 1.5 for derivative Id to value of about 10 for IIId. It was influenced by type of linkage and medium. The decay of fluorescence of linked pyrene chromophore of probes Id–IVd is better fitted by biexponential function.

Jet-induced Explosions of Core Collapse Supernovae

We numerically studied the explosion of a supernova caused by supersonic jets present in its center. The jets are assumed to be generated by a magnetorotational mechanism when a stellar core collapses into a neutron star. We simulated the process of the jet propagation through the star, jet breakthrough, and the ejection of the supernova envelope by the lateral shocks generated during jet propagation. The end result of the interaction is a highly nonspherical supernova explosion with two high-velocity jets of material moving in polar directions and slower moving, oblate, highly distorted ejecta containing most of the supernova material. The jet-induced explosion is entirely due to the action of the jets on the surrounding star and does not depend on neutrino transport or reacceleration of a stalled shock. The jet mechanism can explain the observed high polarization of Types Ib, Ic, and IIsupernovae, pulsar kicks, very high velocity material observed in supernova remnants, indications that radioactive material was carried to the hydrogen-rich layers in SN 1987A, and other observations that are very difficult or impossible to explain by the neutrino energy deposition mechanism. The breakout of the jet from a compact, hydrogen-deficient core may account for the γ-ray burst and radio outburst associated with SN 1998bw/GRB 980425.

A Gene on Chromosome 11q23 Coding for a Putative Glucose- 6-Phosphate Translocase Is Mutated in Glycogen-Storage Disease Types Ib and Ic

Glycogen-storage diseases type I (GSD type I) are due to a deficiency in glucose-6-phosphatase, an enzymatic system present in the endoplasmic reticulum that plays a crucial role in blood glucose homeostasis. Unlike GSD type Ia, types Ib and Ic are not due to mutations in the phosphohydrolase gene and are clinically characterized by the presence of associated neutropenia and neutrophil dysfunction. Biochemical evidence indicates the presence of a defect in glucose-6-phosphate (GSD type Ib) or inorganic phosphate (Pi) (GSD type Ic) transport in the microsomes. We have recently cloned a cDNA encoding a putative glucose-6-phosphate translocase. We have now localized the corresponding gene on chromosome 11q23, the region where GSD types Ib and Ic have been mapped. Using SSCP analysis and sequencing, we have screened this gene, for mutations in genomic DNA, from patients from 22 different families who have GSD types Ib and Ic. Of 20 mutations found, 11 result in truncated proteins that are probably nonfunctional. Most other mutations result in substitutions of conserved or semiconserved residues. The two most common mutations (Gly339Cys and 1211-1212 delCT) together constitute approximately 40% of the disease alleles. The fact that the same mutations are found in GSD types Ib and Ic could indicate either that Pi and glucose-6-phosphate are transported in microsomes by the same transporter or that the biochemical assays used to differentiate Pi and glucose-6-phosphate transport defects are not reliable.

Bile duct cysts in adults: a multi-institutional retrospective study. French Associations for Surgical Research.

To review the features of adult patients undergoing surgery for bile duct cysts, focusing on the anatomy of the biliary tree as well as the long-term outcome. Bile duct cysts (BDCs) are uncommon in Western countries, and the majority of reported cases originate from Asia. Japanese authors have emphasized the frequent association of extra- and intrahepatic bile duct dilatations, but grading of patients based on Todani's classification is often hindered by the absence of an accurate definition of types IC and IVA cysts. Moreover, despite the increasing use of extrahepatic cyst excision, little is known about the long-term outcome in patients with intrahepatic bile duct involvement. Forty-two adult patients with BDC were treated between 1980 and 1992 in 17 institutions of the French Associations for Surgical Research. Clinical presentation, radiologic presurgical evaluation, and surgical procedures were analyzed. The long-term postsurgical outcome was derived from patient charts, attending physicians, or direct patient contact. Twelve patients (30%) had recurrent abdominal pain or jaundice from childhood. Seven (17%) had undergone prior cystenterostomy. Twenty-one (50%) had a Todani-type IVA cyst with extra- and intrahepatic bile duct involvement. Of these, nine had segmental, exclusively left-sided intrahepatic bile duct dilatation. Biliary carcinoma was encountered in five patients (12%). Extrahepatic cyst excision with a Roux-en-Y hepaticojejunostomy was performed in 34 patients with type I or IV cysts. The overall operative mortality rate was 2.4%. Long-term results were clearly correlated with cyst type: during a mean follow-up of 8.4 years, 11 of 12 patients (92%) treated by cyst excision for type I cyst remained free of symptoms, whereas 31% of patients who underwent surgery for type IV cyst had episodic or severe cholangitis with intrahepatic stones. In patients with BDC, particular attention must be given to the associated intrahepatic bile duct dilatations. We propose a modification of Todani's classification to distinguish cystic, segmental, and fusiform dilatations of the intrahepatic biliary tree in type IV cysts. In patients with segmental left intrahepatic cystic dilatations, combined left liver lobectomy and extrahepatic cyst excision is suggested to decrease late postsurgical biliary complications.

Phylogenetic relationships of the mitochondrial genomes in the genus Glycine subgenus Soja.

Restriction fragment length polymorphisms (RFLPs) of mitochondrial DNA (mtDNA) of wild and cultivated soybeans were analyzed to study their phylogenetic relationships. The observed number of differences in hybridization profiles greatly varied (1-17 patterns) with both the mtDNA probes and the restriction enzymes that were used. A cladistic analysis was conducted based on the RFLP data. In the parsimonious tree, four distinct groups appeared among 20 accessions of the subgenus Soja representing 20 mitochondrial genome types. Common features with regard to geographic distributions in natural populations in East Asia were observed among the mitochondrial genome types of wild soybean that belonged to the same group: one clade consisted of genome types IIg and VIIg that are detected with very low frequencies; another clade consisted of genome types Ic, Id, Ie, and Ik whose distributions are highly biased mainly in Japan. The genome types that are widely distributed in East Asia such as IVa, IVb, and Va were not grouped into the same clade. The mitochondrial genome types IIIb, IVb, and IVc, in which two different chloroplast genome types exist, belonged to the same clade. Possible changes in mitochondrial genomes during the expansion of the distribution of wild soybeans in East Asia were discussed.

On the Light Curves of Stripped‐Envelope Supernovae

Representative light curves of supernovae of Types Ib and Ic, and the peculiar Type II that makes a transition to Ib, are collected and analyzed. Their main characteristics are (1) a group of fast and heterogeneous light curves corresponding to spectroscopic Type Ic and (2) a group of intermediate and homogeneous light curves among which are examples of spectroscopic Types Ib, Ic, and II transition. The latter have a well-defined slope of ~0.019 mag day-1 after ~150 days. A simple model based on the deposition of the energy provided by the radioactive decay of 56Ni and 56Co in expanding spherical shells is presented and used to qualitatively explain these families of light curves. The γ-ray deposition function has two different regimes. At early times, it is strongly dependent on the physical parameters of the shells, which explains the heterogeneity of group 1 above. At late times, however, it reaches an asymptotic regime in which the slope in excess of the 56Co decay rate is given by 5t-1 log e mag day-1, where t is the time since explosion in days, independently of any parameter of the ejecta. The photometric group 2 above may be, at least partially, a result of this asymptotic behavior.

Chirp (2–7 kHz) echo characters in the Ulleung Basin

High-resolution (Chirp, 2–7 kHz) reflection profiles in the Ulleung Basin (35–37°N) made it possible to classify the uppermost (ca. 50–70 m thick) sedimentary sequence into eleven discrete echo types. They are either (1) distinct (Echo Types IA, IB, IC, ID, IE, and IF), (2) indistinct (Echo Types IIA, IIB, and IIC), (3) hyperbolic (Echo Type III), or (4) combined (Echo Type IV).

Epidemiological analysis of Malassezia pachydermatis isolates by partial sequencing of the large subunit ribosomal RNA

The opportunistic yeast Malassezia pachydermatis is commonly recovered from both normal and diseased skin of warm-blooded animals. The diversity of M pachydermatis isolates obtained from a wide range of hosts was investigated by the partial sequencing of the large subunit ( LSU) ribosomal RNA. Among 100 isolates examined, seven types (la-1g) were discriminated on the basis of nucleotide sequence diversity. The seven types differed by one to five mutations, all of them corresponding to transitions. The predominant sequence, type la, appeared to be ubiquitous since it was observed in isolates recovered from domestic and wild carnivora, from a monkey and from man. In contrast the sequence types Ic, Id and Ig seemed to be more host-specific; they included isolates recovered exclusively from rhinoceros, dogs and ferrets, respectively. None of the seven sequence types correlated with isolation from healthy skin or a particular lesion (otitis externa or other dermatitis). The study indicated that the skin of an animal may be colonised by more than one type of M pachydermatis.

A carbon–oxygen star as progenitor of the type Ic supernova 1994I

SUPERNOVAE are classified observationally as type I (which have no hydrogen emission lines in their optical spectra) or type II (which do have hydrogen lines), and are further subdivided1 into types Ia, Ib, Ic, IIP, IIL and IIb. Type II supernovae are generally thought to result from the explosion of massive stars, and type Ia supernovae from white-dwarf stars that have accreted sufficient mass from a companion to trigger explosion1,2. The origins of types Ib and Ic are much less clear. The Ic class has been particularly controversial, with two main alternatives: the explosion of a massive star that has lost its hydrogen and helium envelopes through fast stellar winds, exposing the carbon- and oxygen-rich core; or the transfer of material to a companion, leaving a small, bare carbon–oxygen (C + O) star which subsequently explodes3,4. We show here that the observed characteristics of SN1994I (in the nearby galaxy NGC5194), which has recently5,6 been classified as type Ic, are best understood on the basis of the second of the two alternatives above: that the progenitor was in a close binary system and lost its outer envelopes, leaving a C + O star (of mass ≈ 2 solar masses) which exploded when its iron core collapsed.

The near-maximum-light spectrum of the type IC supernova 1987M

An analysis of the near-maximum-light optical and near-UV spectrum of the Type Ic supernova 1987M is presented. In the spectrum, in addition to the fairly certain identifications of O I, Ca II, and optical Fe II lines, we identify a weak Hα line, a moderately weak Si II λ6355 doublet, and the He I λ5876 line. The near-UV region of the spectrum is found to result from a, blend of iron peak ion lines, with only solar abundances of the iron peak elements required in the supernova atmosphere. It is concluded that hydrogen is underabundant relative to solar composition in the supernova atmosphere by at least a factor of 10; no lower limit on hydrogen abundance has been determined. It is also concluded that a helium star model for Type Ic supernovae is adequate and slightly favored for explaining the analyzed spectrum. The implications of the spectrum analysis for explosion models of Types Ib and Ic supernovae are discussed.

Proarrhythmia: A Paradoxic Response to Antiarrhythmic Agents

Antiarrhythmic drugs may effectively terminate and prevent symptomatic tachycardias, but they may also provoke life-threatening rhythm disturbances. The electrophysiologic mechanisms responsible for proarrhythmia can be extrapolated from the existing models of reentry and abnormal automaticity. Although all antiarrhythmic drugs may cause proarrhythmia with seemingly similar frequency, the profile of the disturbance with each class of agents appears somewhat distinct. All agents may cause an increased frequency of premature beats or new or worsened ventricular tachycardia, but the classic form of proarrhythmia due to type la agents is torsades de pointes. Recent information has provided clues to the underlying mechanism of drug-induced torsades de pointes and has provided a clinical picture of patients with this adverse effect. Types lb and lc agents only rarely precipitate torsades de pointes. The latter, however, may cause a rapid, sustained, monomorphic ventricular tachycardia in certain high-risk patients that can be resistant to resuscitation efforts. Amiodarone may cause a broad variety of arrhythmias that are complicated by their extended duration and difficulty in distinguishing proarrhythmia from simple inefficacy. Proarrhythmia is a relatively common, paradoxic side effect that necessitates the clinician to make careful risk-benefit decisions in choosing antiarrhythmic drug therapy.

Plasma level of estradiol in patients with ovarian malignant tumors

Plasma concentration of estradiol has been investigated in women with epithelial ovarian carcinoma. Forty-nine postmenopausal and/or oophorectomized women with no other malignant or endocrine disease were included in the study. All FIGO stages and the histological types IC, IIC, IIIC, and V were represented. Tumor volumes were evaluated once a month using bimanual recto-vaginal palpation under full anesthesia. Blood samples were drawn for estradiol radioimmunoassay at monthly intervals during 3 months. Plasma levels were compared with a control group of postmenopausal women with no internal disease or medication. The results show a significantly higher concentration in patients with large tumor volume compared to postmenopausal controls and a positive relationship between tumor volume, stage, and plasma estradiol level. Histological type seems to be of less importance and secondary to tumor volume. During chemotherapy the plasma concentration of estradiol decreased rapidly with the reduction of tumor volume.