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Purpose: After Endoscopic Enucleation of the Prostate (EEP) for benign prostatic obstruction (BPO), men remain at risk for prostate cancer (PCa). Significant PSA changes occur after enucleation, which interfere with later screening for PCa. It remains unclear which patients need further diagnostic investigations for PCa after EEP. The goal of this study was to identify an independent predictor for PCa diagnosis after Holmium Laser Enucleation of the Prostate (HoLEP) in patients whose HoLEP resection specimen did not show PCa. Methods: Data of 773 patients who underwent HoLEP for BPO between 2010 and 2018 in a referral center were analyzed. Exclusion criteria were PCa detection in the HoLEP specimen or absence of post-operative PSA values. Patients were divided in a PCa group and Control group depending on whether or not PCa was detected during follow-up after HoLEP. The predictive value for future diagnosis of PCa of different forms of PSA-change after HoLEP was analyzed by multivariate Cox regression and ROC analysis. Results: Overall, 24 (4.2%) patients developed PCa after HoLEP. At 5 year follow-up, the PCa-free survival rate was 85%. First post-operative PSA was an independent predictor of PCa diagnosis after HoLEP (HR 1.106, 95% CI 1.074–1.139, p < 0.001, ROC AUC 0.903) with an optimal cut-off value of 1.73 ng/ml (sensitivity 83.3%, specificity 82.3%). Conclusions: For patients who underwent HoLEP for BPO, post-operative PSA after HoLEP is an independent predictor for future PCa diagnosis. When PSA is > 1.73 ng/ml within the first year after HoLEP, rigorous follow-up and diagnostic investigations for PCa are indicated. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to evaluate the changes in maternal quality of life (QOL) from pregnancy to 6 weeks after delivery between routine labor epidural analgesia (EA) and pain relief on maternal request only.Methods: \Women delivering of a singleton in cephalic presentation beyond 36 + 0 weeks' gestation were randomly allocated to EA as a routine during labor (routine EA group), or to any kind of analgesia on request only (control group). The Short Form health survey (SF-36) was used to assess women's QOL before randomization, and 6 weeks postpartum. Data were analyzed according to the intention to treat principle.Results: A total of 488 women were included, and antepartum as well as postpartum SF-36 questionnaires were filled in by 356 (73.0%) women, 176 (49.4%) in the routine EA group, and 180 (50.6%) in the control group. Changes from the QOL antepartum to the QOL 6 weeks postpartum were comparable between both groups, also in the subgroup of women in the control group who gave birth without any pain medication (n = 41, 22.8%). Maternal age and the incidence of adverse events related to EA, which were both higher in the routine EA group, had no influence on the changes in QOL. Differences in request for pain relief were comparable with other studies.Conclusion: Routine administration of EA during labor and pain relief on maternal request only are associated with comparable changes of women's QOL antepartum to 6 weeks postpartum. [ABSTRACT FROM AUTHOR]

Heat engines provide most of our mechanical power and are essential for transportation on the macroscopic scale. However, although significant progress has been made in the miniaturization of electrostatic engines, it has proved difficult to reduce the size of liquid- or gas-driven heat engines below 107 μm3. Here we demonstrate that a crystalline silicon structure operates as a cyclic piezoresistive heat engine when it is driven by a sufficiently high d.c. current. A 0.34 μm3 engine beam draws heat from the d.c. current using the piezoresistive effect and converts it into mechanical work by expansion and contraction at different temperatures. This mechanical power drives a silicon resonator of 1.1×103 μm3 into sustained oscillation. Even below the oscillation threshold the engine beam continues to amplify the resonator's Brownian motion. When its thermodynamic cycle is inverted, the structure is shown to reduce these thermal fluctuations, therefore operating as a refrigerator. [ABSTRACT FROM AUTHOR]

The efficacy of fast – slow MHD mode conversion in the surface layers of sunspots has been demonstrated over recent years using a number of modelling techniques, including ray theory, perturbation theory, differential eigensystem analysis, and direct numerical simulation. These show that significant energy may be transferred between the fast and slow modes in the neighbourhood of the equipartition layer where the Alfvén and sound speeds coincide. However, most of the models so far have been two dimensional. In three dimensions the Alfvén wave may couple to the magnetoacoustic waves with important implications for energy loss from helioseismic modes and for oscillations in the atmosphere above the spot. In this paper, we carry out a numerical “scattering experiment,” placing an acoustic driver 4 Mm below the solar surface and monitoring the acoustic and Alfvénic wave energy flux high in an isothermal atmosphere placed above it. These calculations indeed show that energy conversion to upward travelling Alfvén waves can be substantial, in many cases exceeding loss to slow (acoustic) waves. Typically, at penumbral magnetic field strengths, the strongest Alfvén fluxes are produced when the field is inclined 30° – 40° from the vertical, with the vertical plane of wave propagation offset from the vertical plane containing field lines by some 60° – 80°. [ABSTRACT FROM AUTHOR]

The role of leaky waves in the coronal loop oscillations observed by TRACE is not yet clearly understood. In this work, the excitation of fast waves in solar coronal loops modelled as dense plasma cylindrical tubes in a uniform straight magnetic field is investigated. We study the trapped and especially leaky modes (whose energy escapes from the tube) that result from an initial disturbance by solving the time-dependent problem numerically. We find that the stationary state of the tube motion is given by the trapped normal modes. By contrast, the transient behaviour between the initial and the stationary phase is dominated by wave leakage. The so-called trig leaky modes are clearly identified since the transient behaviour shows periods and damping times that are in agreement with the values calculated from the normal-mode analysis. Consequently, these radiating modes have physical significance. However, we have not found any evidence for the excitation of other types of modes, such as the principal leaky kink mode. [ABSTRACT FROM AUTHOR]

The cancer risk is unknown for those families in which a microsatellite instable tumour is neither explained by MLH1 promoter methylation nor by a germline mutation in a mismatch repair (MMR) gene. Such information is essential for genetic counselling. Families suspected of Lynch syndrome (n = 614) were analysed for microsatellite instability, MLH1 promoter methylation and/or germline mutations in MLH1, MSH2, MSH6, and PMS2. Characteristics of the 76 families with a germline mutation (24 MLH1, 2 PMS2, 32 MSH2, and 18 MSH6) were compared with those of 18 families with an unexplained microsatellite instable tumour. The mean age at diagnosis of the index patients in both groups was comparable at 44 years. Immunohistochemistry confirmed the loss of an MMR protein. Together this suggests germline inactivation of a known gene. The Amsterdam II criteria were fulfilled in 50/75 families (66%) that carried a germline mutation in an MMR gene and in only 2/18 families (11%) with an unexplained microsatellite instable tumour (P<0.0001). Current diagnostic strategies can detect almost all highly penetrant MMR gene mutations. Patients with an as yet unexplained microsatellite instable tumour likely carry a different type of mutation that confers a lower risk of cancer for relatives. [ABSTRACT FROM AUTHOR]

Hereditary non-polyposis colorectal cancer (HNPCC) is caused by mutations in one of the mismatch repair genes MLH1, MSH2, MSH6, or PMS2 and results in high-level microsatellite instability (MSI-high) in tumours of HNPCC patients. The MSI test is considered reliable for indicating mutations in MLH1 and MSH2, but is questioned for MSH6. Germline mutation analysis was performed in 19 patients with an MSI-high tumour and absence of MSH2 and/or MSH6 protein as determined by immunohistochemistry (IHC), without an MLH1 or MSH2 mutation, and in 76 out of 295 patients suspected of HNPCC, with a non-MSI-high colorectal cancer (CRC). All 295 non-MSI-high CRCs were analysed for presence of MSH6 protein by IHC. In 10 patients with an MSI-high tumour without MSH2 and/or MSH6 expression, a pathogenic MSH6 mutation was detected, whereas no pathogenic MSH6 mutation was detected in 76 patients with a non-MSI-high CRC and normal MSH6 protein expression. In none of the 295 CRCs loss of MSH6 protein expression was detected. The prevalence of a germline MSH6 mutation is very low in HNPCC suspected patients with non-MSI-high CRC. Microsatellite instability analysis in CRCs is highly sensitive to select patients for MSH6 germline mutation analysis. [ABSTRACT FROM AUTHOR]

We will discuss the observed, heavily damped transversal oscillations of coronal loops. These oscillations are often modeled as transversal kink oscillations in a cylinder. Several features are added to the classical cylindrical model. In our models we include loop curvature, longitudinal density stratification, and highly inhomogeneous radial density profiles. In this paper, we will first give an overview of recently obtained results, both analytically and numerically. After that, we shed a light on the computational aspects of the modeling process. In particular, we will focus on the parallellization of the numerical codes. [ABSTRACT FROM AUTHOR]

The influence of a constant coronal magnetic field on solar global oscillations is investigated for a simple planar equilibrium model. The model consists of an atmosphere with a constant horizontal magnetic field and a constant sound speed, on top of an adiabatic interior having a linear temperature profile. The focus is on the possible resonant coupling of global solar oscillation modes to local slow continuum modes of the atmosphere and the consequent damping of the global oscillations. In order to avoid Alfvén resonances, the analysis is restricted to propagation parallel to the coronal magnetic field. Parallel propagating oscillation modes in this equilibrium model have already been studied by Evans and Roberts (1990). However, they avoided the resonant coupling to slow continuum modes by a special choice of the temperature profile. The physical process of resonant absorption of the acoustic modes with frequency in the cusp continuum is mathematically completely described by the ideal MHD differential equations which for this particular equilibrium model reduce to the hypergeometric differential equation. The resonant layer is correctly dealt with in ideal MHD by a proper treatment of the logarithmical branch cut of the hypergeometric function. The result of the resonant coupling with cusp waves is twofold. The eigenfrequencies become complex and the real part of the frequency is shifted. The shift of the real part of the frequency is not negligible and within the limit of observational accuracy. This indicates that resonant interactions should definitely be taken into account when calculating the frequencies of the global solar oscillations. [ABSTRACT FROM AUTHOR]

The SOX10 transcription factor is involved in development of neural crest derivatives and fate determination in glial cells. SOX10 mutations have been found in patients with intestinal aganglionosis and depigmentation with deafness (Waardenburg-Hirschsprung). Associated neurological signs have been reported in some cases, including a patient exhibiting a central and peripheral myelin deficiency. Therefore, we screened for SOX10 mutations in a large cohort of patients with peripheral and central myelin disorders. 56 were affected by classical demyelinating Charcot-Marie-Tooth disease without identified mutations in the genes encoding PNS myelin proteins (PMP22, P0), connexin 32 and the zinc-finger transcription factor, EGR2. 88 patients with undetermined leukodystrophy were selected from a large European prospective study. Associated clinical, magnetic resonance imaging and electrophysiological signs were consistent with a defect in CNS myelination in 83 and with an active degeneration of the CNS myelin in 5. No abnormalities in the proteolipid protein gene (PLP) were found. The absence of SOX10 mutation in this large cohort of patients suggests that this gene is not frequently involved in peripheral or central inherited myelin disorders. [ABSTRACT FROM AUTHOR]

To study slow electromagnetic processes of induction type in a hot collisionless nonmagnetized high-beta plasma near magnetic-reconnection regions, where the influence of eddy electric currents on magnetic-field configuration should be described self-consistently, we develop a kinetic description in the quasi-current-free (QCF) approximation, which includes the quasi-neutral approximation. The QCF approximation is valid for large-scale nonstationary processes if the scale of spatial inhomogeneity of the fields exceeds the scale of the diamagnetic current screening, the anomalous skin scale, and the polarization-screening scale. In this case, the diamagnetic currents are compensated by the conductivity currents. The equations of the QCF approximation for accelerated particles with narrow distribution functions are formulated as the MHD equations. To illustrate the method, we consider a one-dimensional problem on magnetic annihilation. The self-similar solution of this problem describes the relaxation of the current system typical for solar streamers and the tail of the Earth's magnetosphere. [ABSTRACT FROM AUTHOR]

This paper studies the effect of a magnetic atmosphere on the global solar acoustic oscillations in a simple Cartesian model. First, the influence of the ratio of the coronal and the photospheric temperature τ and the strength of the magnetic field at the base of the corona Bc on the oscillation modes is studied for a convection zone-corona model with a true discontinuity. The ratio τ seems to be an important parameter. Subsequently, the discontinuity is replaced by an intermediate chromospheric layer of thickness L and the effect of the thickness on the frequencies of the acoustic waves is studied. In addition, nonuniformity in the magnetic field, plasma density and temperature in the transition layer gives rise to continuous Alfvén and slow spectra. Modes with characteristic frequencies lying within the range of the continuum may resonantly couple to Alfvén and/or slow waves. [ABSTRACT FROM AUTHOR]

Characterization of unstable hemoglobins by protein analysis is often difficult. However, it is facilitated by DNA analysis, especially in the case of hyperunstable beta-chain variants, which produce a beta-thalassemia phenotype. We have applied an efficient strategy to the detection of such variants at the DNA level, based on computer-designed denaturing gradient gel electrophoresis (DGGE) of amplified DNA fragments. This approach makes it possible to detect any anomaly in the beta-globin gene. We describe the use of the DGGE method for rapid characterization of beta-chain variants and report a new missense mutation in the beta-globin gene third exon, beta 127 CAG-CGG/Gln-Arg, which is responsible for the synthesis of a highly unstable hemoglobin. [ABSTRACT FROM AUTHOR]

DNA diagnosis of hemophilias has received much attention in recent years, and different methods are presently available to analyze the coagulation factor IX and VIII genes. This review is intended to serve as a brief guide to current and emerging diagnostic strategies. [ABSTRACT FROM AUTHOR]

Hb Puttelange [β140(H18)Ala→Val] was found as a de novo mutation in two siblings of a French family suffering from polycythemia. Both parents were phenotypically normal and exclusion of paternity has been ruled out by the study of several polymorphic markers located on different chromosomes. The structural modification of Hb Puttelange was established by reversed-phase HPLC analysis of the tryptic digest of the abnormal chain. The amino acid composition of an abnormal βT14 peptide revealed that one of the four residues of Ala was replaced by a Val. Tandem mass spectrometry demonstrated that the substitution concerned position β140 (H18). This hemoglobin displays an increased oxygen affinity that is responsible for the polycythemia. De novo mutations, as demonstrated again in the case of this variant, have the highest probabilities of detection when they lead to pathological manifestations. They may result either from a somatic mutation in a very early stage of the embryological development of the propositus or may have a parental origin with occurrence of a germline mosaicism. The study of the β-globin gene indicated that this case of Hb Puttelange probably arose from a mutation affecting a part of the germline of the father, therefore leading to a true recurrence risk. [ABSTRACT FROM AUTHOR]

The stability equations for localized (or ballooning) modes in the solar atmosphere are formulated. Dissipation due to viscosity, resistivity, and thermal conduction are included using the general forms due to Braginskii (1965). In addition, the effect of gravity, plasma radiation, and coronal heating are included. The resulting equations are one-dimensional and only involve derivatives along the equilibrium magnetic field. Thus, the stabilising influence of photospheric line-tying, which is normally neglected in most numerical simulations, can be studied in a simple manner. Two applications to sound wave propagation and thermal instabilities in a low-beta plasma are considered with a view to determining realistic coronal boundary conditions that model the lower, denser levels of the solar atmosphere in a simple manner. [ABSTRACT FROM AUTHOR]

The study of resistive ballooning instabilities in line-tied coronal magnetic fields is extended by including viscosity in the stability analysis. The equations that govern the resistive ballooning instabilities are derived and the effects of parallel and perpendicular viscosity are included using Braginskii's stress tensor. Numerical solutions to these equations are obtained under the rigid wall boundary conditions for arcades with cylindrically-symmetric magnetic fields. It is found that viscosity has a stabilizing effect on the resistive ballooning instabilities with perpendicular viscosity being more important by far than parallel viscosity. The strong stabilizing effect of perpendicular viscosity can lead to complete stabilization for realistic values of the equilibrium quantities. [ABSTRACT FROM AUTHOR]

A first attempt is made to study the continuous spectrum of linear ideal MHD for 2D solar loops and to understand how 2D effects change the continuum eigenfrequencies and continuum eigenfunctions. The continuous spectrum is computed for 2D solar loops with purely poloidal magnetic fields and it is investigated how non-circularity of the cross-sections of the poloidal magnetic surfaces and variations of density along the poloidal magnetic field lines change the continuous spectrum and induce poloidal wave number coupling in the eigenfunctions. Approximate analytical results and numerical results are obtained for the eigenfrequencies and the eigenfunctions and the poloidal wave number coupling is clearly illustrated. It is found that the continuum frequencies are substantially increased, that the ranges of the continuum frequencies are considerably enlarged and that the derivatives of the continuum frequencies normal to the magnetic surfaces are substantially increased. The eigenfunctions are strongly influenced by poloidal wave number coupling. Implications of these findings for the heating mechanisms of resonant absorption and phase mixing are briefly considered. [ABSTRACT FROM AUTHOR]

The continuous spectrum of a 2D magnetostatic equilibrium with y-invariance is derived. It is shown that the continuous spectrum is given by an eigenvalue problem on each magnetic surface and is related to the different behaviour of the equilibrium quantities in different magnetic surfaces. The special case of a uniform poloidal magnetic field in a 1D equilibrium that is stratified with height, has been considered in detail and it is found that there is no continuous spectrum. It is shown that this result relies completely on the artificial property that the behaviour of the equilibrium quantities along a magnetic field line is independent of the field line considered. As a consequence the non-existence of a continuous spectrum in a 1D equilibrium with a uniform magnetic field cannot be used to argue that the continuous spectrum has no physical relevance. [ABSTRACT FROM AUTHOR]

The energy-loss spectrum of high energy muons after traversal of a 10 meter iron degrader has been measured with an accuracy of better than 1%. Data taken at energies between 50 and 120 GeV are in agreement with predictions from a Monte Carlo program based on the most recent theoretical descriptions of all relevant processes. The stopping power calculated by this program deviates up to several percent from earlier calculations. [ABSTRACT FROM AUTHOR]

This review discusses Alfvén wave heating in non-uniform plasmas as a possible means for explaining the heating of the solar corona. It focusses on recent analytical results that enable us to understand the basic physics of Alfvén wave heating and help us with the interpretation of results of numerical simulations. First we consider the singular wave solutions that are found in linear ideal MHD at the resonant magnetic surface where the frequency of the wave equals the local Alfvén frequency. Next, we use linear resistive MHD for describing the waves in the dissipative region and explain how dissipation modifies the singular solutions found in linear ideal MHD. [ABSTRACT FROM AUTHOR]

σ-stability analysis is used to investigate the adiabatic stability of a star containing an axisymmetric toroidal magnetic field. Necessary and sufficient conditions for σ-stability are derived. Special attention is devoted to the typical hydromagnetic instabilities that can be introduced by a weak toroidal magnetic field in a star that is stably stratified in the absence of any magnetic field. An expression for the maximum growth rate of instability is derived and the basic properties of the displacement fields associated with the instabilities are indicated. [ABSTRACT FROM AUTHOR]

The perturbation problem that describes the effect of a weak magnetic field on stellar adiabatic oscillation is considered. This perturbation problem is singular when the magnetic field does not vanish at the stellar surface, and a regular perturbation scheme fails where the magnetic pressure is comparable to the thermodynamic pressure. The application of the Method of Matched Asymptotic Expansion is used to obtain expressions for the eigenfunctions and the eigenfrequencies. [ABSTRACT FROM AUTHOR]

The solar corona, modeled by a low- β, resistive plasma slab, sustains MHD wave propagations due to footpoint motions in the photosphere. Simple test cases are undertaken to verify the code. Uniform, smooth and steep density, magnetic profile and driver are considered. The numerical simulations presented here focus on the evolution and properties of the Alfvén, fast and slow waves in coronal loops. The plasma responds to the footpoint motion by kink or sausage waves depending on the amount of shear in the magnetic field. The larger twist in the magnetic field of the loop introduces more fast-wave trapping and destroys initially developed sausage-like wave modes. The transition from sausage to kink waves does not depend much on the steep or smooth profile. The slow waves develop more complex fine structures, thus accounting for several local extrema in the perturbed velocity profiles in the loop. Appearance of the remnants of the ideal singularities characteristic of ideal plasma is the prominent feature of this study. The Alfvén wave which produces remnants of the ideal x singularity, reminiscent of Alfvén resonance at the loop edges, becomes less pronounced for larger twist. Larger shear in the magnetic field makes the development of pseudo-singularity less prominent in case of a steep profile than that in case of a smooth profile. The twist also causes heating at the edges, associated with the resonance and the phase mixing of the Alfvén and slow waves, to slowly shift to layers inside the slab corresponding to peaks in the magnetic field strength. In addition, increasing the twist leads to a higher heating rate of the loop. Remnants of the ideal log ¦ x¦ singularity are observed for fast waves for larger twist. For slow waves they are absent when the plasma experiences large twist in a short time. The steep profiles do not favour the creation of pseudo-singularities as easily as in the smooth case. [ABSTRACT FROM AUTHOR]

We study the dispersion characteristics of fast MHD surface waves travelling on a plasma slab immersed in a complex magnetic field consisting of a large longitudinal B component and a small sheared B component. The analysis shows that for typical coronal conditions both the sausage and kink waves are generally pseudo-surface waves. The tangential magnetic field, B, modifies the dispersion curves, and for sufficiently large sheared fields there is a transition from pseudo-surface to pure-surface fast kink waves. [ABSTRACT FROM AUTHOR]

A WKB approach, based on the method of Connor, Hastie, and Taylor (1979), is used to obtain simple estimates of the critical conditions for the onset of ideal MHD instabilities in line-tied solar coronal loops. The method is illustrated for the constant twist, Gold-Hoyle (1960) field, and the critical conditions are compared with previous and new numerical results. For the force-free case, the WKB estimate for the critical loop length reduces to $$2\pi m + \sqrt 2 \pi$$ . For the sufficiently non-force-free case the critical length can be expressed in the form l + l / m. The results confirm the findings of De Bruyne and Hood (1992) that for force-free fields the m = 1 mode is the first mode to become unstable but for the sufficiently strong non-force-free case this reverses with the m → ∞ mode being excited first. [ABSTRACT FROM AUTHOR]

The normal mode spectrum for the linearized MHD equations is investigated for a cylindrical equilibrium. This spectrum is examined for zero perpendicular thermal conduction, with both zero and non-zero scalar resistivity. Particular attention is paid to the continuous branches of this spectrum, or continuous spectra. For zero resistivity there are three types of continuous spectra present, namely the Alfvén, slow, and thermal continua. It is shown that when dissipation due to resistivity is included, the slow and Alfvén continua are removed and that the thermal continuum is shifted to a different position (where the shift is independent of the exact value of resistivity). The 'old' location of the thermal continuum is covered by a dense set of nearly singular discrete modes called a quasi-continuum. The quasi-continuum is investigated numerically, and the eigenfunctions are shown to have rapid spatial oscillating behaviour. These oscillations are confined to the most unstable part of the equilibrium based on the Field criterion, and may be the cause of fine structure in prominences. [ABSTRACT FROM AUTHOR]

Approximate solutions of the linearized non-adiabatic MHD equations, obtained using the ballooning method, are compared with 'exact' numerical solutions of the full equations (including the effects of optically thin plasma radiation). It is shown that the standard ballooning method, developed within the framework of ideal linear MHD, can be generalized to non-ideal linear MHD. The localized (ballooning) spectrum has to be used with caution, but can give valuable (though limited) information on non-ideal stability. The numerical analysis also confirms and quantifies the interesting connection between magnetic and thermal instabilities. The existence of such a coupling is inherent in many qualitative discussions of magnetic disruptions. Finally, the hitherto unrecognized role of the thermal continuum in the unstable part of the 'magnetothermal' spectrum is investigated. [ABSTRACT FROM AUTHOR]

The linear MHD spectrum is investigated for cylindrical equilibrium models under typical coronal conditions. Non-ideal effects are included and attention is focussed on the thermal instability and the influence of perpendicular thermal conduction. It is shown that, when thermal conduction across magnetic field lines is neglected, the 'classic' Alfvén and slow continua are supplemented by a new 'thermal' continuum. Surprisingly, the existence of this non-ideal continuous spectrum appears to have been overlooked for a very long time. Unlike the (still purely oscillatory) Alfvén continuum modes and the slow continuum modes (overstable or damped), the thermal continuum modes are exponentially growing or decaying in time. As with the Alfvén and slow continua, discrete modes may be present above or below the thermal continuum, depending upon the choice of equilibrium parameters. These modes are localized using a simple WKB approach. The knowledge of the thermal subspectrum is then exploited to find necessary and sufficient conditions for instability. The inclusion of perpendicular thermal conduction eliminates this thermal continuum, but replaces it by a dense set of eigenmodes located at the same values of the growth rate. It is shown that perpendicular thermal conduction has no significant influence on the thermal stability of the equilibrium, though individual modes may be strongly influenced. The corresponding eigenfunctions still have a nearly-singular behaviour, but in addition they may contain a rapid spatial oscillation on a scale proportional to some power of the perpendicular thermal conduction coefficient. This rapid oscillation is confined to the most unstable part of the equilibrium and may be of relevance for the formation of fine-scale structure (threads) in prominences. [ABSTRACT FROM AUTHOR]

The stability of ballooning modes in coronal arcades is studied using linear visco-resistive MHD. Rigid wall conditions are adopted for modelling the photospheric line-tying of the magnetic field. The full Braginskii viscosity stress tensor is used and particular attention is given to the effect of the viscosity coefficient η which was left out of an earlier investigation by Van der Linden, Goossens, and Hood (1987, 1988). The numerical results for shearless arcades show that the coefficient η has a stabilizing effect. However, for realistic values of the equilibrium quantities the stabilizing effect by η can be neglected in comparison with the strong stabilizing effect of the perpendicular viscosity. The effect of magnetic field strength and mode number on stability are determined. In particular it is found that there exists a critical field strength for every mode number such that the mode is stable for weaker fields and unstable for stronger fields. [ABSTRACT FROM AUTHOR]

Prominences and filaments are thought to arise as a consequence of a magnetized plasma undergoing thermal instability. Therefore, the thermal stability of a magnetized plasma is investigated under coronal conditions. The equilibrium structure of the plasma is approximated by a 1-D slab configuration. This is investigated in thermal instability taking into account optically thin plasma radiation and anisotropic thermal conduction. The thermal conduction perpendicular to the magnetic field is taken to be small but non-zero. The classic rigid wall boundary conditions which are often applied in the literature, either directly on the plasma or indirectly through some other medium, are replaced by a more physical situation in which the plasma column is placed in a low-density background stretching towards infinity. Results for a uniform equilibrium structure indicate the major effect of this change is on the eigenfunctions rather than on the growth rate. Essentially, perpendicular thermal conduction introduces field-aligned fine structure. It is also shown that in the presence of perpendicular thermal conduction, thermal instability in a slab model is only possible if the inner plasma has the shortest thermal instability time scale. [ABSTRACT FROM AUTHOR]

Dominant megacolon ( Dom) is one of four mutations in the mouse that can produce a phenotype similar to Hirschsprung disease in human. The Dom gene product is not known, and no candidate region has been defined for a possible human homolog. In this publication we report mapping the Dom locus with high definition, using several intra- and interspecific crosses and a set of 16 Chr 15-specific microsatellites flanking this locus. [ABSTRACT FROM AUTHOR]

We have determined the spectrum of mutations producing β-thalassemia (β-thal) in Tunisia by direct DNA analysis using hybridization with allele-specific oligonucleotide probes and restriction endonuclease assay. In all, 34 unrelated β-thal patients originating from different parts of the country were available for study. The β-globin gene cluster of each was subjected to haplotype analysis, and on the basis of this analysis, we tested each patient's DNA for one or more mutations previously shown to be linked to that haplotype. We identified four previously unreported haplotypes and found that this population differs from others in Mediterranean areas in the frequency of the β-thal haplotypes, the unexpected observation being the high frequency of haplotype IX. Six different point mutations were found, accounting for 62% of β-thal genes in this Tunisian population. The molecular defects known to be the most frequent in Mediterraneans (nonsense codon 39, IVS1 nt 110, IVS1 nt 6) only make up 37% of the mutant genes. One as yet undescribed mutation (IVS1 nt 2 T → G) was identified by molecular cloning and sequencing. Our results should help the implementation of a prenatal diagnosis program for β-thal in Tunisia. [ABSTRACT FROM AUTHOR]

A cDNA probe corresponding to mRNA encoding human uroporphyrinogen decarboxylase (URO-D) was used to determine the chromosomal localization of the URO-D gene in the human genome. In agreement with previous studies, we have found that the locus for URO-D is located on chromosome 1 in hybrid cell mapping panels. The use of in sity hybridization allowed us to map the URO-D locus to band 1p34. [ABSTRACT FROM AUTHOR]

We have determined the frequency of the cystic fibrosis (CF) ΔF508 mutation in a large sample of CF patients originating from different areas of France, including the greater Paris, Brittany, Alsace, Lorraine and Rhône-Alpes regions. A total of 422 CF chromosomes were studied, and the defect was found to account for 75% of the mutant alleles. In the course of the survey, a rare nucleotide sequence polymorphism leading to an isoleucine to valine substitution at position 506 of the CF transmembrane conductance regulator protein has been characterized in an unaffected individual. Our data enable the evaluation of the probabilities that a chromosome negative for the ΔF508 mutation carriers another CF defect. [ABSTRACT FROM AUTHOR]