Fano q-reversal in topological insulator Bi2Se3.

We studied the magneto-optical response of a canonical topological insulator Bi2Se3 with the goal of addressing a controversial issue of electron-phonon coupling. Magnetic-field induced modifications of reflectance are very pronounced in the infrared part of the spectrum, indicating strong electron-phonon coupling. This coupling causes an asymmetric line-shape of the 60 cm(-1) phonon mode, and is analyzed within the Fano formalism. The analysis reveals that the Fano asymmetry parameter (q) changes sign when the cyclotron resonance is degenerate with the phonon mode. To the best of our knowledge this is the first example of magnetic field driven q-reversal.

Electron-phonon and magnetoelastic interactions in ferromagnetic Co[N(CN)2]2.

We combined Raman and infrared vibrational spectroscopies with complementary lattice dynamics calculations and magnetization measurements to reveal the dynamic aspects of charge-lattice-spin coupling in Co[N(CN)2]2. Our work uncovers electron-phonon coupling as a magnetic field-driven avoided crossing of the low-lying Co2+ electronic excitation with two ligand phonons and a magnetoelastic effect that signals a flexible local CoN6 environment. Their simultaneous presence indicates the ease with which energy is transferred over multiple length and time scales in this system.

Quantum critical transition amplifies magnetoelastic coupling in Mn[N(CN)2]2.

We report the discovery of a magnetic quantum critical transition in Mn[N(CN)(2)](2) that drives the system from a canted antiferromagnetic state to the fully polarized state with amplified magnetoelastic coupling as an intrinsic part of the process. The local lattice distortions, revealed through systematic phonon frequency shifts, suggest a combined MnN(6) octahedra distortion+counterrotation mechanism that reduces antiferromagnetic interactions and acts to accommodate the field-induced state. These findings deepen our understanding of magnetoelastic coupling near a magnetic quantum critical point and away from the static limit.

Interaction-induced shift of the cyclotron resonance of graphene using infrared spectroscopy.

We report a study of the cyclotron resonance (CR) transitions to and from the unusual n=0 Landau level (LL) in monolayer graphene. Unexpectedly, we find the CR transition energy exhibits large (up to 10%) and nonmonotonic shifts as a function of the LL filling factor, with the energy being largest at half filling of the n=0 level. The magnitude of these shifts, and their magnetic field dependence, suggests that an interaction-enhanced energy gap opens in the n=0 level at high magnetic fields. Such interaction effects normally have a limited impact on the CR due to Kohn's theorem [W. Kohn, Phys. Rev. 123, 1242 (1961)], which does not apply in graphene as a consequence of the underlying linear band structure.

Magnetoelastic coupling through the antiferromagnet-to-ferromagnet transition of quasi-two-dimensional [Cu(HF2)(pyz)2]BF4 using infrared spectroscopy.

We investigated magnetoelastic coupling through the field-driven transition to the fully polarized magnetic state in quasi-two-dimensional [Cu(HF2)(pyz)2]BF4 by magnetoinfrared spectroscopy. This transition modifies out-of-plane ring distortion and bending vibrational modes of the pyrazine ligand. The extent of these distortions increases with the field, systematically tracking the low-temperature magnetization. These distortions weaken the antiferromagnetic spin exchange, a finding that provides important insight into magnetic transitions in other copper halides.

Cyclotron resonance in bilayer graphene.

We present the first measurements of cyclotron resonance of electrons and holes in bilayer graphene. In magnetic fields up to B=18 T, we observe four distinct intraband transitions in both the conduction and valence bands. The transition energies are roughly linear in B between the lowest Landau levels, whereas they follow square root[B] for the higher transitions. This highly unusual behavior represents a change from a parabolic to a linear energy dispersion. The density of states derived from our data generally agrees with the existing lowest order tight binding calculation for bilayer graphene. However, in comparing data to theory, a single set of fitting parameters fails to describe the experimental results.

Infrared spectroscopy of Landau levels of graphene.

We report infrared studies of the Landau level (LL) transitions in single layer graphene. Our specimens are density tunable and show in situ half-integer quantum Hall plateaus. Infrared transmission is measured in magnetic fields up to B=18 T at selected LL fillings. Resonances between hole LLs and electron LLs, as well as resonances between hole and electron LLs, are resolved. Their transition energies are proportional to sqrt[B], and the deduced band velocity is (-)c approximately equal to 1.1 x 10(6) m/s. The lack of precise scaling between different LL transitions indicates considerable contributions of many-particle effects to the infrared transition energies.

Heat shock protein 70 and tumor necrosis factor alpha in Taiwanese patients with dementia.

This study was to determine whether polymorphisms of heat shock protein 70-1 (HSP70-1) and tumor necrosis factor alpha (TNF-alpha) are associated with the risk of Alzheimer's disease (AD) and vascular dementia (VaD). Using the criteria of the NINCDS-ADRDA and NINDS-AIREN, 125 AD patients, 57 VaD patients and 109 ethnically matched nondemented controls were enrolled. The HSP70-1 -110 A/C and TNF-alpha -1031 T/C, -863 C/A and -857 C/T polymorphisms were analyzed by means of genotype or haplotype association methods. None of the four genotypes examined showed a statistically significant difference in genotype distribution between the AD cases and controls. However, the HSP70-1 -110 CC genotype occurred more frequently among AD cases (p=0.0821; odds ratio: 2.08; 95% confidence interval, CI: 0.92-4.98). The overall genotype distribution among the VaD cases tended to be different at the HSP70-1 -110 and TNF-alpha -1031 sites (p=0.0604 and 0.0316, respectively). The HSP70-1 -110 CC genotype was more frequent (p=0.0459), and the association of the -110 CC genotype with VaD was evident (p=0.0207; odds ratio: 3.22; 95% CI: 1.20-8.87). The more frequent TNF-alpha -1031 TC genotype (p=0.0614) was also evidently associated with VaD (p=0.0209; odds ratio: 2.32; 95% CI: 1.14-4.78). Multivariate analysis demonstrated the synergistic effect of the HSP70-1 -110 CC and TNF-alpha -1031 TC/CC genotypes on VaD (p=0.0091; odds ratio: 10.09; 95% CI: 2.01-75.97). Haplotype analysis among TNF-alpha -1031, -863, -857 sites revealed that -1031C-857C may act as a risk haplotype among VaD cases (p=0.0132, odds ratio: 2.26; 95% CI: 1.19-4.33). Our results suggest a potential protective role for HSP70 in both VaD and AD, whereas TNF-alpha may act as a risk factor only for VaD, and not for AD.

Genetic testing in spinocerebellar ataxia in Taiwan: expansions of trinucleotide repeats in SCA8 and SCA17 are associated with typical Parkinson's disease.

DNA tests in normal subjects and patients with ataxia and Parkinson's disease (PD) were carried out to assess the frequency of spinocerebellar ataxia (SCA) and to document the distribution of SCA mutations underlying ethnic Chinese in Taiwan. MJD/SCA3 (46%) was the most common autosomal dominant SCA in the Taiwanese cohort, followed by SCA6 (18%) and SCA1 (3%). No expansions of SCA types 2, 10, 12, or dentatorubropallidoluysian atrophy (DRPLA) were detected. The clinical phenotypes of these affected SCA patients were very heterogeneous. All of them showed clinical symptoms of cerebellar ataxia, with or without other associated features. The frequencies of large normal alleles are closely associated with the prevalence of SCA1, SCA2, MJD/SCA3, SCA6, and DRPLA among Taiwanese, Japanese, and Caucasians. Interestingly, abnormal expansions of SCA8 and SCA17 genes were detected in patients with PD. The clinical presentation for these patients is typical of idiopathic PD with the following characteristics: late onset of disease, resting tremor in the limbs, rigidity, bradykinesia, and a good response to levodopa. This study appears to be the first report describing the PD phenotype in association with an expanded allele in the TATA-binding protein gene and suggests that SCA8 may also be a cause of typical PD.

Sonographic diagnosis of hydronephrosis in patients with spinal cord injury: influence of bladder fullness.

OBJECTIVE: To investigate and compare the diagnostic accuracy of prevoid and postvoid renal sonography in detecting hydronephrosis in patients with spinal cord injury. STUDY DESIGN: A prospective, blind comparison of renal sonography and excretory urography in 67 spinal cord injury patients who underwent periodic urologic examinations. Renal sonography was performed twice, once when the patient's bladder was physiologically full (prevoid) and again when it was just emptied (postvoid). RESULTS: Of 140 kidneys, 24 from 16 patients were found to have hydronephrosis by excretory urography; 116 kidneys had normal urogram findings. Prevoid sonography missed the diagnosis of hydronephrosis in one kidney and showed hydronephrosis in 18 kidneys that had normal results on excretory urography (sensitivity, 95.8%; specificity, 84.5%; negative predictive value, 99.0%). The postvoid sonograms did not detect hydronephrosis in four kidneys and showed hydronephrosis in six kidneys that had normal results on excretory urography (sensitivity, 83.3%; specificity, 94.8%; negative predictive value, 96.5%). Compared to excretory urography, renal sonography detected eight more upper urinary tract abnormalities, which were confirmed by cystograms or radioisotopic renograms. CONCLUSION: Performing renal sonography while the bladder is full can increase the sensitivity in detecting hydronephrosis in asymptomatic spinal cord injured patients.

[Characteristics of appendicitis in patients over 70 years of age]. / Die Besonderheiten der Appendizitis jenseits des 70. Lebensjahres.

Chart review of our patients who were operated for acute appendicitis was performed to characterize the appendicitis in the elder patients. Celiotomy revealed perforation of the appendix in almost 40%, frequently in patients with unspecific symptoms and no leucocytosis. While mortality was 9.2% in the ninteeneighties, non of our patients died during the last 5.5 years. This might be attributed to emergency operation, improved anaesthesia and intensive medical care.

Prognostic indicators in fulminant hepatic failure.

Because of the inhomogeneous prognosis in fulminant hepatic failure, prognostic criteria are required which help to establish the indication for liver transplantation as a successful therapeutic procedure. In our study of 33 patients with fulminant hepatic failure (94% viral hepatitis, 67% hepatitis B), serum bilirubin > 320 or < 160 mumol/L, serum creatinine > 110 mumol/L, prothrombin time < 15% of the normal value and duration of jaundice until onset of encephalopathy > 7 days indicated a fatal outcome. When criteria described by O'Grady et al. were used, only limited predictability was achieved. This, as well as the frequently contradictory results of the few prognostic studies published so far, is probably due to the regional differences in the etiology and the different clinical courses of fulminant hepatic failure.

[Combination therapy of gallbladder stones using extracorporeal shock waves and bile acids: results in relation to stone diameter and stone number]. / Kombinierte Therapie von Gallenblasensteinen mit extrakorporalen Stosswellen und Gallensäuren: Ergebnisse in Abhängigkeit von Steindurchmesser und Steinzahl.

420 patients were referred to our center for gallstone lithotripsy. 97 patients (23%) with radiolucent gallbladder stones (total diameter less than or equal to 3 cm) and intact gallbladder function were found suitable for extracorporal shock-wave lithotripsy. Disintegration of gallbladder stones was achieved in 92 of the 97 patients (95%). Chenodeoxycholic acid and ursodeoxycholic acid were used as adjuvant litholytic therapy. The therapeutic results were evaluated cumulatively in 90 patients after a follow-up of 10 months. 80% of patients with solitary stones (less than or equal to 20 mm in diameter (n = 46) had a stone-free gallbladder, whereas patients with solitary stones greater than 2 cm, less than or equal to 3 cm in diameter (n = 20) and multiple stones (n = 22) became stone-free in only 28% (p less than 0.01). During the observation period 21 patients (23%) experienced biliary colics, 2 (2%) mild pancreatitis, 2 (2%) showed fragment impaction in the common bile duct, and 17 (19%) displayed transient microscopic hematuria. Our results confirm previous studies showing that solitary stones sized up to 2 cm in diameter represent the best suited subgroup for extracorporeal shock-wave lithotripsy.

Reduction of highly elevated plasma levels of gamma-aminobutyric acid does not reverse hepatic coma.

The pathogenesis of coma in patients with fulminant hepatic failure is still unknown, but there is some evidence that decreased hepatic metabolism of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) may be involved. If this hypothesis is true, reduction of increased GABA levels in patients with hepatic encephalopathy should reduce the depth of hepatic coma. In the case described here, highly elevated plasma GABA levels were reduced by cross-circulation with baboon liver. No amelioration of the coma was observed, thus suggesting that decreased hepatic metabolism of GABA is not critically involved in hepatic encephalopathy.

[Leiomyosarcoma of the inferior vena cava. Diagnosis--therapy--prognosis]. / Das Leiomyosarkom der Vena cava inferior. Diagnostik--Therapie--Prognose.

Leiomyosarcoma of the vena cava inferior is a mesenchymal tumor originating from the smooth muscle fibers of the vascular wall. This tumor is usually slow-growing and expansile growth. Prior to the sonographic and computer-tomographic era the tumor was usually only discovered during autopsy or surgery without any preoperative suspicion. Today, the most efficient imaging methods for exact localization, delineation or demonstration of relations to the vascular lumen and local extent are sonography and computer tomography. Caudal cavography is called upon for preoperative demonstration of the venous collateral circulation and thrombotic vascular occlusion.

[Gastroduodenal surgery in patients over 80]. / Gastroduodenale Chirurgie bei Patienten über 80 Jahre.

Between 1969 and 1981 surgery was performed in 118 patients over eighty years old with gastroduodenal diseases. The main indications were carcinomas and ulcers. The combined mortality amounted to 34.8%. One of the main problems of surgery in elder patients turned out to be the simultaneous presence of accompanying diseases. Whenever possible surgery should be performed before the onset of complications.