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We performed modal analysis using frequency domain decomposition of ambient seismic vibration data collected on large rock slope instabilities. This technique enables a robust detection of resonance frequencies and provides the corresponding mode shape vectors. We applied the technique to synthetic and field data sets acquired by seismometer arrays on two rock instabilities in Switzerland. We found that, at the fundamental mode, the entire instability vibrates in‐phase with the dominant mode shape vector oriented perpendicular to dominant fracture systems. At higher frequencies, different compartments of the instability resonate antiphase. Therefore, delineating the zero crossings between the phases allows dominant fractures to be efficiently mapped. Approximately 1 hr of ambient vibration data suffices to apply the method successfully. The method also potentially detects hidden fractures that cannot be observed by geological field mapping. In addition, this approach combines classic amplification and polarization analysis into one technique, simplifying data processing efforts. Large engineered structures, such as tall buildings, show very large amplification of vibrations at distinct frequencies (resonance modes). Measuring these vibrations allows engineers to derive information about the structure, for example, information on the stiffness and geometry of the object investigated. In this study, resonance mode analysis of ambient seismic vibration data was applied on two unstable mountain slopes that can be considered as large natural structures. We installed arrays of seismometers across the instabilities and recorded the ambient seismic vibrations for approximately 1 hr. We found that the instabilities are indeed vibrating at distinct resonance modes and that the direction of deflection is perpendicular to the large‐scale fracture system. At resonance modes of higher frequencies, separate units of the instability are vibrating in opposite directions. We verified our findings using a computer model of one of the unstable slopes. The technique presented in this paper can support geologists in mapping the dominant fracture network of the unstable slope. This approach allows slopes to be mapped quickly and efficiently, only requiring a few hours of seismic data recording. In contrast, slope mapping based on displacement monitoring (e.g., Global Navigation Satellite System) often requires longer time series of up to several years. Measuring resonance frequencies based on ambient seismic data can support fracture mapping on rock slope instabilitiesWe applied operational modal analysis using frequency domain decompositionOur experimental findings are verified by finite difference modeling

Accurate assessments of the internal structure and boundary conditions of unstable rock slopes are imperative for evaluating landslide hazard scenarios. However, instability characterization at depth remains challenging and is often limited by costly or invasive subsurface investigations. Here, we develop a new approach coupling array‐based ambient vibration modal analysis and numerical modeling to improve structural characterization of rock slope instabilities at depth. We used ambient noise cross‐correlation on 4 hr of seismic data recorded by an array of 30 nodal geophones at a 500‐m‐long toppling rock slab in Utah, USA to identify modal frequencies between 0.8 and 3.5 Hz and derive modal displacements. We show that transverse and longitudinal bending modes span the length of the instability, indicating an interconnected slab. Statistical comparison of field results with outputs from >1,000 finite element models with varying boundary conditions showed that the instability depth varies between 40–70 and 10–20 m in the middle and lateral regions, respectively. Our approach yields new information on the structural conditions of rock cliff and column instabilities at depth, which is not easily obtained by other means but is imperative for change detection monitoring and improved hazard assessments. Rock slope failures constitute a major hazard in areas with steep terrain and can endanger human lives and damage infrastructure. An important step in minimizing the hazard from unstable rock slopes is obtaining a detailed picture of the structure and geometry of an instability, including size, material properties, and the manner in which failure is likely. Characterizing the structure of landslides below the surface, however, remains challenging and is often costly or requires intrusive measurements. We developed a new approach that combines surface‐based measurements of the natural vibrations of an unstable rock cliff with numerical modeling to improve estimates of the instability geometry. We measured the vibrational properties of a large unstable rock slab in southern Utah, USA and compared the results of our field data analysis with >1,000 model iterations to narrow down the possible geometries of the instability below the surface. This technique improved our assessment of the instability size and structure, and has the potential to be a valuable tool for similar evaluations at other unstable rock slopes. We combine ambient vibration modal analysis and numerical modeling to assess structural conditions of a toppling rock slab in Utah, USAMode shapes derived from geophone array data are used to calibrate numerical eigenfrequency models and invert for boundary conditionsOur approach can be applied in other settings to enhance characterization of unstable rock slopes in support of improved hazard assessments We combine ambient vibration modal analysis and numerical modeling to assess structural conditions of a toppling rock slab in Utah, USA Mode shapes derived from geophone array data are used to calibrate numerical eigenfrequency models and invert for boundary conditions Our approach can be applied in other settings to enhance characterization of unstable rock slopes in support of improved hazard assessments

Varicella zoster virus (VZV) vasculopathy produces stroke secondary to viral infection of cerebral arteries. Not all patients have rash before cerebral ischemia or stroke. Furthermore, other vasculitides produce similar clinical features and comparable imaging, angiographic, and CSF abnormalities.

To describe three unrelated children with a distinctive variant of Aicardi-Goutières syndrome (AGS) characterized by microcephaly, severe mental and motor retardation, dyskinesia or spasticity, and occasional seizures.

Previous CSF studies in Rett syndrome suggest reduced turnover of the biogenic monoamines serotonin and dopamine. Because diminished turnover may result from CNS folate depletion, the authors studied transport of folate across the blood–brain barrier.

Interstitial lung disease, although of prognostic impact for patients with cystic fibrosis (CF), remains difficult to assess without histopathologic investigations. As changes of peripheral blood lymphocyte subsets (LS) may accompany severe systemic lymphocyte immune responses, we compared peripheral LS of 44 patients with CF, 23 non-CF patients with recurrent pulmonary infections and 83 healthy controls (flow cytometry; CD3, CD19, CD16, CD56, CD4, CD8, CD11b, CD45RA, CD45RO, HLA-DR and CD25 antigens). Additional immunohistochemistry was performed on lung tissue of four CF patients aged 0·5, 12, 17 and 20 years, respectively. Patients with CF showed low absolute counts of CD4+CD45RO+memory helper T cells, CD16+CD56+NK cells, CD8+and interleukin-2 receptor-positive T cells in peripheral blood (P<0·001). Similar changes were registered in the non-CF patients with pulmonary infections, indicating that those were not specific for CF. Immunohistochemistry showed activation of bronchus-associated lymphoid tissue with interstitial accumulation of CD4+CD45RO+T cells in the three older patients. Patients with CF show marked changes of peripheral blood LS which are presumably not CF-specific and may mirror homing to lung tissue in the course of interstitial lung disease. Further research should evaluate its usefulness in monitoring progression of lung disease in CF.

Tryptophan hydroxylase (TPH; EC 1.14.16.4) catalyzes the first rate-limiting step of serotonin biosynthesis by converting l-tryptophan to 5-hydroxytryptophan. Serotonin controls multiple vegetative functions and modulates sensory and alpha-motor neurons at the spinal level. We report on five boys with floppiness in infancy followed by motor delay, development of a hypotonic-ataxic syndrome, learning disability, and short attention span. Cerebrospinal fluid (CSF) analysis showed a 51 to 65% reduction of the serotonin end-metabolite 5-hydroxyindoleacetic acid (5HIAA) compared to age-matched median values. In one out of five patients a low CSF 5-methyltetrahydrofolate (MTHF) was present probably due to the common C677T heterozygous mutation of the methylenetetrahydrofolate reductase (MTHFR) gene. Baseline 24-h urinary excretion showed diminished 5HIAA values, not changing after a single oral load with l-tryptophan (50–70 mg/kg), but normalizing after 5-hydroxytryptophan administration (1 mg/kg). Treatment with 5-hydroxytryptophan (4–6 mg/kg) and carbidopa (0.5–1.0 mg/kg) resulted in clinical amelioration and normalization of 5HIAA levels in CSF and urine. In the patient with additional MTHFR heterozygosity, a heterozygous missense mutation within exon 6 (G529A) of the TPH gene caused an exchange of valine by isoleucine at codon 177 (V177I). This has been interpreted as a rare DNA variant because the pedigree analysis did not provide any genotype-phenotype correlation. In the other four patients the TPH gene analysis was normal. In conclusion, this new neurodevelopmental syndrome responsive to treatment with 5-hydroxytryptophan and carbidopa might result from an overall reduced capacity of serotonin production due to a TPH gene regulatory defect, unknown factors inactivating the TPH enzyme, or selective loss of serotonergic neurons.

Clinical experience with the treatment of 3-phosphoglycerate dehydrogenase deficiency, a rare inherited disorder of serine synthesis, is scarce. We report on two sisters with phenotypic heterogeneity and a favourable response to combined serine and glycine supplementation. The elder sibling was found to be normocephalic at birth and showed moderate delay of white matter myelinisation, while her seizures arrested spontaneously even without treatment. In the younger sister with the classical phenotype, feeding difficulties with recurrent gastro-oesophageal reflux prompted us to treat her temporarily with high-dose serine (1400 mg/kg/day). An arrest of head growth then occurred but could be reversed by reducing the serine supply. In both children serine therapy was associated with decreased concentrations of methionine, isoleucine, and ornithine in the cerebrospinal fluid, attributed to competitive inhibition of neutral amino acid transport across the blood-brain barrier. In contrast to reports in the literature, these findings demonstrate that congenital microcephaly, intractable seizures, and dysmyelinisation are not invariably present in patients with 3-phosphoglycerate dehydrogenase deficiency. An adverse effect of high-dose serine therapy on head growth and on the transport of neutral amino acids across the blood-brain barrier should be considered and requires adjustment of treatment.

The structure and operating conditions of the unit connection of generator and HVDC converter are described. The specific requirements of the plant being isolated from other AC networks are considered both for normal operation and for operation at transient or persistent faults.

AbstractThe clinical importance of somatostatin type-2 receptors (SSTR2) and the study of novel analogues of somatostatin such as OctreoScan or [Tyr3]-octreotide containing DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) as metal chelator led us to develop a methodology to monitor the expression of SSTR2 on tumours of pancreatic origin (e.g. rat AR4-2J cancer cells). Usual binding assay protocols using the commercial [125I][Tyr1]-somatostatin radioligand failed, even in the presence of a cocktail of protease inhibitors with a broad spectrum of activity, possibly due to the high susceptibility of this tracer to proteases expressed in pancreatic cells. We prepared our own radioligand [125I][Tyr3]-octreotide which was shown to be much more resistant to degradation after incubation with AR4-2J plasma membranes. As expected, the increased stability of [125I][Tyr3]-octreotide was associated with good binding to SSTR2. Addition of appropriate protease inhibitors further increased the specific binding of [125I][Tyr3]-octreotide to AR4-2J plasma membranes without affecting the stability of the tracer, suggesting that the protease inhibitors also protect the integrity of SSTR2. Optimal conditions (time, temperature, medium) were developed for a binding assay in 96-well plates using AR4-2J plasma membranes in order to make the assay suitable for high-throughput analysis. This protocol was the basis for studying the in vivo regulation of SSTR2 expression in AR4-2J cells implanted into scid mice after exposure to different compounds.

During the test of a new technology for the manufacture of allylchloride 60 persons were exposed to increased allylchloride concentrations in the ambient air (MAK=1 ppm) for a duration of 16 months. Reports in the literature of acute animal tests indicate kidney- and liver damage as well as irritation of the mucosae. Clinical and laboratory examinations of persons exposed to low concentrations allylchloride showed that liver damage may occur. Especially for liver functiontest some enzyme activities in the serum were determined. In the course of the exposure an increase in activity was observed with both mitochondrially and cytoplasmatically localized enzymes. There is rapid normalisation of liver functiontests after stop of the work in this plant, as could be demonstrated by repeated reexamination.

Summary The characterization and quantitation of indoles by thin-layer chromatography followed by fluorometric scanning of the chromatographed species on the thin-layer provides a rapid and sensitive method of analysis at theµg level and lower. Considerable increases in fluorescence intensity may be achieved if the plate is sprayed with a polar compound such as dimethylsulfoxide prior to measurement. The method may be used to quantitatively determine directly 50 ng samples of serotonin and indoleacetic acid and should be equally sensitive for other indolic compounds. The analysis of biological extracts for low levels of indoles should be a particular application for the method.

Reliable monitoring of unstable rock slopes is a prerequisite for successful mitigation of landslide hazards. However, most state‐of‐the art techniques rely on measuring the local surface displacement in the potential release area. In contrast, recording ambient vibration data allows for analyzing structural dynamic parameters of the unstable slope, such as resonance frequency, polarization of vibration, and energy dissipation. These parameters can be linked to properties of the instability, for example, to rock stiffness and fracture network orientation. We developed a processing method for continuous seismic data based on enhanced frequency domain decomposition modal analysis and applied it to the unstable rock slope Preonzo in Switzerland (∼140,000 m3). Four years of ambient vibration data recorded at two permanent seismometers on the instability were analyzed, providing the resonance frequency, damping ratio, and normal mode shapes of the fundamental (∼3.5 Hz) and the first higher (∼4.2 Hz) vibrational mode. We found that modal analysis can be reliably used to monitor the dynamic response of an unstable rock slope. We observed annual changes of all parameters with a damping ratio varying between 6.0% and 9.7% for the fundamental mode. The dynamic parameters appear to be primarily driven by temperature and only secondarily by opening and closing of fractures. No large slope failure was registered during the observation period. However, the data provide a baseline model for ongoing slope monitoring to recognize structural changes before a future collapse. The setup proposed builds a complementary monitoring system to displacement‐based surveying. Engineered structures, such as bridges and tall buildings, are vibrating at distinct frequencies, called resonance frequencies. Measuring these vibrations helps engineers to obtain important information about the structure, for example, information about the stiffness of the building. Tracking the resonance frequency over time can be used to monitor the object and to register damages before they lead to a catastrophic collapse of the structure. In our study, we applied this technique to a large unstable rock slope and observed the resonance frequency over a period of four years. In addition, we also monitored the direction of vibration as well as damping, which is a measure of how much energy is leaving the structure during vibrations. We did not observe any rock collapse during the monitoring period. However, we found that the resonance frequency and the direction of vibration strongly depend on temperature, causing repeatable annual cycles. The resonance frequency is especially low in spring during the snow melting period, which is also the time when rock fractures open rapidly. We expect a significant drop in resonance frequency before a potential future collapse. Therefore, our data and the technique proposed can be used for ongoing monitoring at this site. We monitored an unstable rock slope using frequency domain decomposition modal analysisWe tracked the resonance frequency, mode shapes, and damping ratio of the fundamental and first higher mode over a period of four yearsOur study shows seasonal variations of all dynamic parameters and a weak linear relationship between frequency and damping ratio We monitored an unstable rock slope using frequency domain decomposition modal analysis We tracked the resonance frequency, mode shapes, and damping ratio of the fundamental and first higher mode over a period of four years Our study shows seasonal variations of all dynamic parameters and a weak linear relationship between frequency and damping ratio

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