The geology of the Vermont Valley and the western flank of the Green Mountains between Dorset Mountain and Wallingford, Vermont

The carbonate sequence of the Vermont Valley has been generally believed to lie on the east limb of a major unfaulted syncline ( Middlebury Synclinorium ), and the exposed Precambrian basement and overlying cover rocks of the Green Mountain massif on the west limb of the adjacent major unfaulted anticline ( Green Mountain Anticlinorium ). Except for the Basal Thrust of the Taconic Allochthon, all faults shown on previous maps die out north of Dorset Mountain. In contrast, detailed mapping for this thesis in the Vermont Valley and the western flank of the Green Mountain massif has revealed several major north/south trending thrust faults, which can be traced through the field area, and document the progressive evolution of the Vermont Valley as a complicated thrust-and-fold belt in four different stages. A tectonically derived, highly-strained rock unit, previously mapped as the Baker Brook volcanics , which separates Ordovician black phyllites of the Hortonville Formation from the shelf carbonates to the east, shows a pervasive transposed and differentiated layering. The fault zone fabrics in these rocks display an anastomosing mylonitic foliation, locally containing coarser fragments derived from intermediate-silicic plutonic rocks, presumed to originate from the Grenville basement. Asymmetrical feldspar porphyroclasts and recrystallized quartz grain shape fabrics give a clear and consistent east-over-west sense of shear. Adjacent Ordovician marbles are mylonites too, with a steeply plunging stretching lineation. This contact between the Middle Ordovician black phyllites and the Cambrian to Early Ordovician shelf units has previously been interpreted as an angular unconformity ( Tinmouth unconformity ). In contrast, I suggest there is a major thrust fault here, which has transported the carbonates in the east over the black phyllites of the Hortonville Formation in the west, named the Baker Brook Thrust (T1). The carbonate sequence is interpreted as a duplex thrust system (T2), that was progressively developed and is necessary to explain the complex structural relationships of the Vermont Valley carbonate shelf units. While overriding a footwall ramp, or alternatively by footwall plucking, underlying basement slices were detached and brought up by the Pine Hill Thrust. The Pine Hill Thrust, which extends through the field area, is believed to be entirely a T2- imbricate thrust of the shelf duplex. Detailed correlation of units of the Vermont marble belt suggest a single, however internally imbricated, large marble slice, attached to the sole of the moving Basal Taconic Thrust and emplaced with the Taconic Allochthon to the west. The overthrust, named the Dorset Mountain Thrust (T2r), truncates all earlier structures north of the Dorset Mountain massif and follows the Basal Taconic Thrust throughout the Vermont Valley. Further progressive shortening during the last stage of deformation culminated in foreland directed thrust faults (Ts), and folding of the shelf duplex; these are presumed to belong to the Taconic Frontal Thrust System. This stage is probably responsible for cross-cutting relationships along the complexly folded western flank of. the Green Mountains (Green Mountain Thrust), and reactivation of some earlier T2-thrust faults. The regional interpretation strongly suggests that the entire Vermont Valley, the eastern part of the Taconic Allochthon to the west, and probably the Green Mountain massif to the east, are underlain by a complicated deformed shelf duplex, which has been cut by major north/south trending, eastward dipping late thrust faults

Prenatal ultrasound screening for fetal anomalies and outcomes in high-risk pregnancies due to maternal HIV infection : a retrospective study

Objective: To assess the prevalence of prenatal screening and of adverse outcome in high-risk pregnancies due to maternal HIV infection. Study design: The prevalence of prenatal screening in 330 pregnancies of HIV-positive women attending the department for prenatal screening and/or during labour between January 1, 2002 and December 31, 2012, was recorded. Screening results were compared with the postnatal outcome and maternal morbidity, and mother-to-child transmission (MTCT) was evaluated. Results: One hundred of 330 women (30.5%) had an early anomaly scan, 252 (74.5%) had a detailed scan at 20–22 weeks, 18 (5.5%) had a detailed scan prior to birth, and three (0.9%) had an amniocentesis. In seven cases (2.12%), a fetal anomaly was detected prenatally and confirmed postnatally, while in eight (2.42%) an anomaly was only detected postnatally, even though a prenatal scan was performed. There were no anomalies in the unscreened group. MTCT occurred in three cases (0.9%) and seven fetal and neonatal deaths (2.1%) were reported. Conclusion: The overall prevalence of prenatal ultrasound screening in our cohort is 74.5%, but often the opportunity for prenatal ultrasonography in the first trimester is missed. In general, the aim should be to offer prenatal ultrasonography in the first trimester in all pregnancies. This allows early reassurance or if fetal disease is suspected, further steps can be taken

RGS9 Knockout Causes a Short Delay in Light Responses of ON-Bipolar Cells

RGS9 and R9AP are components of the photoreceptor-specific GTPase activating complex responsible for rapid inactivation of the G protein, transducin, in the course of photoresponse recovery from excitation. The amount of this complex in photoreceptors is strictly dependent on the expression level of R9AP; consequently, the knockouts of either RGS9 or R9AP cause comparable delays in photoresponse recovery. While RGS9 is believed to be present only in rods and cones, R9AP is also expressed in dendritic tips of ON-bipolar cells, which receive synaptic inputs from photoreceptors. Recent studies demonstrated that knockouts of R9AP and its binding partner in ON-bipolar cells, RGS11, cause a small delay in ON-bipolar cell light responses manifested as a delayed onset of electroretinography b-waves. This led the authors to suggest that R9AP and RGS11 participate in regulating the kinetics of light responses in these cells. Here we report the surprising finding that a nearly identical b-wave delay is observed in RGS9 knockout mice. Given the exclusive localization of RGS9 in photoreceptors, this result argues for a presynaptic origin of the b-wave delay in this case and perhaps in the case of the R9AP knockout as well, since R9AP is expressed in both photoreceptors and ON-bipolar cells. We also conducted a detailed analysis of the b-wave rising phase kinetics in both knockout animal types and found that, despite a delayed b-wave onset, the slope of the light response is unaffected or increased, dependent on the light stimulus intensity. This result is inconsistent with a slowdown of response propagation in ON-bipolar cells caused by the R9AP knockout, further arguing against the postsynaptic nature of the delayed b-wave phenotype in RGS9 and R9AP knockout mice

Optimization of Mass Spectrometry Imaging for Drug Metabolism and Distribution Studies in the Zebrafish Larvae Model: A Case Study with the Opioid Antagonist Naloxone

Zebrafish (ZF; Danio rerio) larvae have emerged as a promising in vivo model in drug metabolism studies. Here, we set out to ready this model for integrated mass spectrometry imaging (MSI) to comprehensively study the spatial distribution of drugs and their metabolites inside ZF larvae. In our pilot study with the overall goal to improve MSI protocols for ZF larvae, we investigated the metabolism of the opioid antagonist naloxone. We confirmed that the metabolic modification of naloxone is in high accordance with metabolites detected in HepaRG cells, human biosamples, and other in vivo models. In particular, all three major human metabolites were detected at high abundance in the ZF larvae model. Next, the in vivo distribution of naloxone was investigated in three body sections of ZF larvae using LC-HRMS/MS showing that the opioid antagonist is mainly present in the head and body sections, as suspected from published human pharmacological data. Having optimized sample preparation procedures for MSI (i.e., embedding layer composition, cryosectioning, and matrix composition and spraying), we were able to record MS images of naloxone and its metabolites in ZF larvae, providing highly informative distributional images. In conclusion, we demonstrate that all major ADMET (absorption, distribution, metabolism, excretion, and toxicity) parameters, as part of in vivo pharmacokinetic studies, can be assessed in a simple and cost-effective ZF larvae model. Our established protocols for ZF larvae using naloxone are broadly applicable, particularly for MSI sample preparation, to various types of compounds, and they will help to predict and understand human metabolism and pharmacokinetics

Drug Administration Routes Impact the Metabolism of a Synthetic Cannabinoid in the Zebrafish Larvae Model

Zebrafish (Danio rerio) larvae have gained attention as a valid model to study in vivo drug metabolism and to predict human metabolism. The microinjection of compounds, oligonucleotides, or pathogens into zebrafish embryos at an early developmental stage is a well-established technique. Here, we investigated the metabolism of zebrafish larvae after microinjection of methyl 2-(1-(5-fluoropentyl)-1H-pyrrolo[2,3-b]pyridine-3-carboxamido)-3,3-dimethylbutanoate (70N-5F-ADB) as a representative of recently introduced synthetic cannabinoids. Results were compared to human urine data and data from the in vitro HepaRG model and the metabolic pathway of 70N-5F-ADB were reconstructed. Out of 27 metabolites detected in human urine samples, 19 and 15 metabolites were present in zebrafish larvae and HepaRG cells, respectively. The route of administration to zebrafish larvae had a major impact and we found a high number of metabolites when 70N-5F-ADB was microinjected into the caudal vein, heart ventricle, or hindbrain. We further studied the spatial distribution of the parent compound and its metabolites by mass spectrometry imaging (MSI) of treated zebrafish larvae to demonstrate the discrepancy in metabolite profiles among larvae exposed through different administration routes. In conclusion, zebrafish larvae represent a superb model for studying drug metabolism, and when combined with MSI, the optimal administration route can be determined based on in vivo drug distribution

Simulation of rotating drum experiments using non-circular particles

We investigate the flow of granular material in a rotating cylinder numerically using molecular dynamics in two dimensions. The particles are described by a new model which allows to simulate geometrically complicated shaped grains. The results of the simulation agree significantly better with experiments than the results which are based on circular particles.Comment: 15 pages, 9 figure

Discovery and overproduction of novel highly bioactive pamamycins through transcriptional engineering of the biosynthetic gene cluster

Background Pamamycins are a family of highly bioactive macrodiolide polyketides produced by Streptomyces alboniger as a complex mixture of derivatives with molecular weights ranging from 579 to 705 Daltons. The large derivatives are produced as a minor fraction, which has prevented their isolation and thus studies of chemical and biological properties. Results Herein, we describe the transcriptional engineering of the pamamycin biosynthetic gene cluster (pam BGC), which resulted in the shift in production profle toward high molecular weight derivatives. The pam BGC library was constructed by inserting randomized promoter sequences in front of key biosynthetic operons. The library was expressed in Streptomyces albus strain with improved resistance to pamamycins to overcome sensitivity-related host limitations. Clones with modifed pamamycin profles were selected and the properties of engineered pam BGC were studied in detail. The production level and composition of the mixture of pamamycins was found to depend on balance in expression of the corresponding biosynthetic genes. This approach enabled the isolation of known pamamycins and the discovery of three novel derivatives with molecular weights of 663 Da and higher. One of them, homopamamycin 677A, is the largest described representative of this family of natural products with an elucidated structure. The new pamamycin 663A shows extraordinary activity (IC50 2 nM) against hepatocyte cancer cells as well as strong activity (in the one-digit micromolar range) against a range of Gram-positive pathogenic bacteria. Conclusion By employing transcriptional gene cluster refactoring, we not only enhanced the production of known pamamycins but also discovered novel derivatives exhibiting promising biological activities. This approach has the potential for broader application in various biosynthetic gene clusters, creating a sustainable supply and discovery platform for bioactive natural products

Evaluation of extraction methods for untargeted metabolomic studies for future applications in zebrafish larvae infection models

Sample preparation in untargeted metabolomics should allow reproducible extractions of as many molecules as possible. Thus, optimizing sample preparation is crucial. This study compared six diferent extraction procedures to fnd the most suitable for extracting zebrafsh larvae in the context of an infection model. Two one-phase extractions employing methanol (I) and a single miscible phase of methanol/acetonitrile/water (II) and two two-phase methods using phase separation between chloroform and methanol/water combinations (III and IV) were tested. Additional bead homogenization was used for methods III and IV (III_B and IV_B). Nine internal standards and 59 molecules of interest (MoInt) related to mycobacterial infection were used for method evaluation. Two-phase methods (III and IV) led to a lower feature count, higher peak areas of MoInt, especially amino acids, and higher coefcients of variation in comparison to one-phase extractions. Adding bead homogenization increased feature count, peak areas, and CVs. Extraction I showed higher peak areas and lower CVs than extraction II, thus being the most suited one-phase method. Extraction III and IV showed similar results, with III being easier to execute and less prone to imprecisions. Thus, for future applications in zebrafsh larvae metabolomics and infection models, extractions I and III might be chosen