Microsnare retrieval as a bail-out technique of Detached Woven EndoBridge device: Illustrative series.

BACKGROUND: The Woven EndoBridge (WEB) device (MicroVention, Tustin, CA, USA) has an excellent safety profile. While major complications such as device malposition and migration are rare, they can have serious consequences if not addressed promptly. Our case series describes the safety and efficacy of Amplatz goose neck microsnare device (Medtronic in Irvine, CA, USA) in endovascular retrieval of a detached WEB device. METHODS: We retrospectively reviewed six consecutive patients who underwent endovascular WEB retrieval using Amplatz microsnare device between March 2012 and December 2022. RESULTS: All six WEB devices were successfully retrieved either directly from the aneurysm sac due to device malpositioning or from a distal branch following device migration. None of the patients experienced intra-operative aneurysm perforation, arterial dissection, or vasospasm attributable to the process of WEB extraction. Five out of six patients (83.3%) had a good functional outcome (mRS 0-1) upon discharge from the hospital and at 24 months. CONCLUSION: Our experience suggests that detached WEB devices can be safely retrieved using an Amplatz microsnare. Apart from addressing device migration, direct removal of an undersized or malpositioned WEB from the aneurysm sac appears to be a safe option that can be considered when all other rescue techniques have been exhausted.

Controls on timescales of soil organic carbon persistence across sub-Saharan Africa.

Given the importance of soil for the global carbon cycle, it is essential to understand not only how much carbon soil stores but also how long this carbon persists. Previous studies have shown that the amount and age of soil carbon are strongly affected by the interaction of climate, vegetation, and mineralogy. However, these findings are primarily based on studies from temperate regions and from fine-scale studies, leaving large knowledge gaps for soils from understudied regions such as sub-Saharan Africa. In addition, there is a lack of data to validate modeled soil C dynamics at broad scales. Here, we present insights into organic carbon cycling, based on a new broad-scale radiocarbon and mineral dataset for sub-Saharan Africa. We found that in moderately weathered soils in seasonal climate zones with poorly crystalline and reactive clay minerals, organic carbon persists longer on average (topsoil: 201 ± 130 years; subsoil: 645 ± 385 years) than in highly weathered soils in humid regions (topsoil: 140 ± 46 years; subsoil: 454 ± 247 years) with less reactive minerals. Soils in arid climate zones (topsoil: 396 ± 339 years; subsoil: 963 ± 669 years) store organic carbon for periods more similar to those in seasonal climate zones, likely reflecting climatic constraints on weathering, carbon inputs and microbial decomposition. These insights into the timescales of organic carbon persistence in soils of sub-Saharan Africa suggest that a process-oriented grouping of soils based on pedo-climatic conditions may be useful to improve predictions of soil responses to climate change at broader scales.

Lateral Compression Manipulation: A Simple Approach for Sizing Taller-Than-Wide Intracranial Aneurysms with the Woven EndoBridge Device.

BACKGROUND AND PURPOSE: The Woven EndoBridge (WEB) system has established itself as a safe and effective option for managing wide-neck bifurcation aneurysms. Addressing aneurysms with a greater height than width using conventional WEB-sizing methods has proved ineffective due to the inherent configuration of the devices. To overcome this limitation, we propose an intuitive approach that involves swapping the width and height dimensions of the aneurysm to determine the appropriate WEB size. MATERIALS AND METHODS: A retrospective analysis was conducted on patients undergoing WEB embolization at a single neuroscience center from March 2013 to February 2023. RESULTS: Twenty-five eligible aneurysms were identified, with the height dimension exceeding the width by an average of 2.33 mm (ranging from 1.4 to 4.5 mm). Of these, 20 cases adhered to the recommended sizing technique, resulting in a 100% success rate of adequate occlusion (14/20 complete occlusion, 6/20 proximal recess filling). In contrast, the outcomes for the remaining 5 cases that did not follow the proposed sizing method were less favorable (P < .05). Among these, 4 cases treated with undersized WEBs showed neck remnants during follow-up, and 1 patient who received an oversized WEB required device replacement during the same procedure. CONCLUSIONS: The simple sizing method we proposed for treating taller-than-wide aneurysms has demonstrated promising results, allowing the WEB system to address twice the original size range of treatable aneurysms. Further research with a larger sample size is recommended.

The accumulation and growth of Pseudomonas aeruginosa on surfaces is modulated by surface mechanics via cyclic-di-GMP signaling.

Attachment of bacteria onto a surface, consequent signaling, and accumulation and growth of the surface-bound bacterial population are key initial steps in the formation of pathogenic biofilms. While recent reports have hinted that surface mechanics may affect the accumulation of bacteria on that surface, the processes that underlie bacterial perception of surface mechanics and modulation of accumulation in response to surface mechanics remain largely unknown. We use thin and thick hydrogels coated on glass to create composite materials with different mechanics (higher elasticity for thin composites; lower elasticity for thick composites) but with the same surface adhesivity and chemistry. The mechanical cue stemming from surface mechanics is elucidated using experiments with the opportunistic human pathogen Pseudomonas aeruginosa combined with finite-element modeling. Adhesion to thin composites results in greater changes in mechanical stress and strain in the bacterial envelope than does adhesion to thick composites with identical surface chemistry. Using quantitative microscopy, we find that adhesion to thin composites also results in higher cyclic-di-GMP levels, which in turn result in lower motility and less detachment, and thus greater accumulation of bacteria on the surface than does adhesion to thick composites. Mechanics-dependent c-di-GMP production is mediated by the cell-surface-exposed protein PilY1. The biofilm lag phase, which is longer for bacterial populations on thin composites than on thick composites, is also mediated by PilY1. This study shows clear evidence that bacteria actively regulate differential accumulation on surfaces of different stiffnesses via perceiving varied mechanical stress and strain upon surface engagement.

Regaining creativity in science: insights from conversation.

The 'early modern' (Renaissance) workshop was predicated on the idea that informal, open-ended cooperation enables participants to experience difference and develop new insights, which can lead to new ways of thinking and doing. This paper presents the insights that emerged from a conversation event that brought wide-ranging voices together from different domains in science, and across the arts and industry, to consider science leadership as we look to the future in a time of interlocking crises. The core theme identified was a need to regain creativity in science; in the methods of scientific endeavours, in the way science is produced and communicated, and in how science is experienced in society. Three key challenges for re-establishing a culture of creativity in science emerged: (i) how scientists communicate what science is and what it is for, (ii) what scientists value, and (iii) how scientists create and co-create science with and for society. Furthermore, the value of open-ended and ongoing conversation between different perspectives as a means of achieving this culture was identified and demonstrated.

Bacterial mechanosensing of surface stiffness promotes signaling and growth leading to biofilm formation by Pseudomonas aeruginosa.

The attachment of bacteria onto a surface, consequent signaling, and the accumulation and growth of the surface-bound bacterial population are key initial steps in the formation of pathogenic biofilms. While recent reports have hinted that the stiffness of a surface may affect the accumulation of bacteria on that surface, the processes that underlie bacterial perception of and response to surface stiffness are unknown. Furthermore, whether, and how, the surface stiffness impacts biofilm development, after initial accumulation, is not known. We use thin and thick hydrogels to create stiff and soft composite materials, respectively, with the same surface chemistry. Using quantitative microscopy, we find that the accumulation, motility, and growth of the opportunistic human pathogen Pseudomonas aeruginosa respond to surface stiffness, and that these are linked through cyclic-di-GMP signaling that depends on surface stiffness. The mechanical cue stemming from surface stiffness is elucidated using finite-element modeling combined with experiments - adhesion to stiffer surfaces results in greater changes in mechanical stress and strain in the bacterial envelope than does adhesion to softer surfaces with identical surface chemistry. The cell-surface-exposed protein PilY1 acts as a mechanosensor, that upon surface engagement, results in higher cyclic-di-GMP levels, lower motility, and greater accumulation on stiffer surfaces. PilY1 impacts the biofilm lag phase, which is extended for bacteria attaching to stiffer surfaces. This study shows clear evidence that bacteria actively respond to different stiffness of surfaces where they adhere via perceiving varied mechanical stress and strain upon surface engagement.

Skin Vascular Resistance Decreases during 5-HT-Induced Hypotension in the Rat.

A recognized vasodilator, the infusion of 5-hydroxytryptamine (5-HT, serotonin) decreases blood pressure through the reduction of total peripheral resistance in the rat. It is not clear which vascular beds/tissues are responsible for this fall. We hypothesized that an increase in blood flow within the skin, measured as an elevated temperature (T) in the thermoregulatory tail and paws, enables at least part of 5-HT-induced reduction in blood pressure through active vasodilation. The temperature of thermoregulatory regions of the skin of an anesthetized male, Sprague Dawley rats were measured using a Optris PI640 thermal camera. The blood pressure of the animal and the temperature of each paw and four locations along the tail (TL1-4) were recorded before, during, and after the infusion of 5-HT at a rate of 25 mg/min into a femoral vein. Contrary to our hypothesis, the temperature of the paws and tail was stable before and during 5-HT infusion and actually increased during the 15-min recovery period. This finding suggests that hyperemia of the skin circulation is not necessary for the fall in blood pressure observed with infused 5-HT, but that a reduction in cutaneous vascular resistance plays a part in the fall in total peripheral resistance.

Perfusion Imaging for Endovascular Thrombectomy in Acute Ischemic Stroke Is Associated With Improved Functional Outcomes in the Early and Late Time Windows.

BACKGROUND: The impact on clinical outcomes of patient selection using perfusion imaging for endovascular thrombectomy (EVT) in patients with acute ischemic stroke presenting beyond 6 hours from onset remains undetermined in routine clinical practice. METHODS: Patients from a national stroke registry that underwent EVT selected with or without perfusion imaging (noncontrast computed tomography/computed tomography angiography) in the early (<6 hours) and late (6-24 hours) time windows, between October 2015 and March 2020, were compared. The primary outcome was the ordinal shift in the modified Rankin Scale score at hospital discharge. Other outcomes included functional independence (modified Rankin Scale score ≤2) and in-hospital mortality, symptomatic intracerebral hemorrhage, successful reperfusion (Thrombolysis in Cerebral Infarction score 2b-3), early neurological deterioration, futile recanalization (modified Rankin Scale score 4-6 despite successful reperfusion) and procedural time metrics. Multivariable analyses were performed, adjusted for age, sex, baseline stroke severity, prestroke disability, intravenous thrombolysis, mode of anesthesia (Model 1) and including EVT technique, balloon guide catheter, and center (Model 2). RESULTS: We included 4249 patients, 3203 in the early window (593 with perfusion versus 2610 without perfusion) and 1046 in the late window (378 with perfusion versus 668 without perfusion). Within the late window, patients with perfusion imaging had a shift towards better functional outcome at discharge compared with those without perfusion imaging (adjusted common odds ratio [OR], 1.45 [95% CI, 1.16-1.83]; P=0.001). There was no significant difference in functional independence (29.3% with perfusion versus 24.8% without; P=0.210) or in the safety outcome measures of symptomatic intracerebral hemorrhage (P=0.53) and in-hospital mortality (10.6% with perfusion versus 14.3% without; P=0.053). In the early time window, patients with perfusion imaging had significantly improved odds of functional outcome (adjusted common OR, 1.51 [95% CI, 1.28-1.78]; P=0.0001) and functional independence (41.6% versus 33.6%, adjusted OR, 1.31 [95% CI, 1.08-1.59]; P=0.006). Perfusion imaging was associated with lower odds of futile recanalization in both time windows (late: adjusted OR, 0.70 [95% CI, 0.50-0.97]; P=0.034; early: adjusted OR, 0.80 [95% CI, 0.65-0.99]; P=0.047). CONCLUSIONS: In this real-world study, acquisition of perfusion imaging for EVT was associated with improvement in functional disability in the early and late time windows compared with nonperfusion neuroimaging. These indirect comparisons should be interpreted with caution while awaiting confirmatory data from prospective randomized trials.

Laboratory exploration of mineral precipitates from Europa's subsurface ocean.

The precipitation of hydrated phases from a chondrite-like Na-Mg-Ca-SO4-Cl solution is studied using in situ synchrotron X-ray powder diffraction, under rapid- (360 K h-1, T = 250-80 K, t = 3 h) and ultra-slow-freezing (0.3 K day-1, T = 273-245 K, t = 242 days) conditions. The precipitation sequence under slow cooling initially follows the predictions of equilibrium thermodynamics models. However, after ∼50 days at 245 K, the formation of the highly hydrated sulfate phase Na2Mg(SO4)2·16H2O, a relatively recent discovery in the Na2Mg(SO4)2-H2O system, was observed. Rapid freezing, on the other hand, produced an assemblage of multiple phases which formed within a very short timescale (≤4 min, ΔT = 2 K) and, although remaining present throughout, varied in their relative proportions with decreasing temperature. Mirabilite and meridianiite were the major phases, with pentahydrite, epsomite, hydrohalite, gypsum, blödite, konyaite and loweite also observed. Na2Mg(SO4)2·16H2O was again found to be present and increased in proportion relative to other phases as the temperature decreased. The results are discussed in relation to possible implications for life on Europa and application to other icy ocean worlds.

A Clinic-Based Quality Improvement Initiative to Increase Screening for Gonorrhea and Chlamydia in Adolescents.

BACKGROUND: Universal screening is a strategy for addressing the limitations of risk-based screening for gonorrhea and chlamydia (GC/CT). This quality improvement (QI) initiative aimed to improve GC/CT screening by implementing universal annual screening for all adolescents ≥ 13 years old. METHODS: At an academic pediatric resident continuity clinic, an interdisciplinary team designed and conducted multiple Plan-Do-Study-Act (PDSA) cycles over one year. The primary aim, and process measure, was to increase the percentage of encounters with screening for GC/CT in the 12 months prior to the encounter to 80%. The secondary outcome measure was rate of detection of GC or CT infection. Further, pulse checks of provider/staff knowledge and adherence were conducted. The balancing measure was denied insurance claims. RESULTS: The mean screening rate of 29.2% increased during the project implementation to 65.1% with several bundles of PDSA cycles. There were no cases of gonorrhea detected in the baseline period or implementation period. The case rate of chlamydia was similar during both periods (from 9.7 per 1,000 adolescent encounters to 10.8 per 1,000 adolescent encounters, p = 0.74). There was similarly high provider/staff knowledge about (p = 0.35) and adherence to (p = 0.06) the screening protocol at 6 and 12 months of implementation. There was no increase in percentage of denied insurance claims. CONCLUSION: This QI initiative doubled rates of GC/CT screening with no statistically significant increase in number of cases.

Enzyme activities and microbial functional diversity in metal(loid) contaminated soils near to a copper smelter.

The monitoring of soil metal(loid) contamination is of global significance due to deleterious effects that metal(loid)s have on living organisms. Soil biological properties such as enzyme activities (EAs) are good indicators of metal(loid) contamination due to their high sensitivity, fast response, and low-cost. Here, the effect of metal(loid) contamination on physicochemical properties and microbial functionality in soils sampled from within 10 km of a Cu smelter is investigated. Soil composite samples were randomly taken within 2, 4, 6, 8 and10 km zones from a mining industry Cu smelter. The EAs of dehydrogenase (DHA), arylsulfatase (ARY), ß-glucosidase, urease, and arginine ammonification (AA) were studied as indicators of metal(loid) contamination, which included the ecological dose (ED50) with respect to Cu and As contents. The community level physiological profile (CLPP), functional diversity, and catabolic evenness were evaluated based on the C-substrate utilisation. All EAs decreased in zones with high degrees of metal(loid) contamination, which also had low TOC and clay contents, reflecting long term processes of soil degradation. Positive and strong relationships between EAs and TOC were found. DHA and ARY activities decreased by approximately 85-90% in highly metal(loid) contaminated soils. DHA and AA showed significant ED50 values associated with available Cu (112.8 and 121.6 mg CuDTPA kg-1, respectively) and total As contents (30.8 and 31.8 mg As kg-1, respectively). The CLPP showed different metabolic profiles along the metal(loid) contamination gradients. Long-term stress conditions in soils close to industrial areas resulted in the decreasing of general biological activity, catabolic capacity, and functional diversity.

Mineral-nutrient relationships in African soils assessed using cluster analysis of X-ray powder diffraction patterns and compositional methods.

Soil mineral compositions are often complex and spatially diverse, with each mineral exhibiting characteristic chemical properties that determine the intrinsic total concentration of soil nutrients and their phyto-availability. Defining soil mineral-nutrient relationships is therefore important for understanding the inherent fertility of soils for sustainable nutrient management, and data-driven approaches such as cluster analysis allow for these relations to be assessed in new detail. Here the fuzzy-c-means clustering algorithm was applied to an X-ray powder diffraction (XRPD) dataset of 935 soils from sub-Saharan Africa, with each diffractogram representing a digital signature of a soil's mineralogy. Nine mineralogically distinct clusters were objectively selected from the soil mineralogy continuum by retaining samples exceeding the 75 % quantile of the membership coefficients in each cluster, yielding a dataset of 239 soils. As such, samples within each cluster represented mineralogically similar soils from different agro-ecological environments of sub-Saharan Africa. Mineral quantification based on the mean diffractogram of each cluster illustrated substantial mineralogical diversity between the nine groups with respect to quartz, K-feldspar, plagioclase, Fe/Al/Ti-(hydr)oxides, phyllosilicates (1:1 and 2:1), ferromagnesians, and calcite. Mineral-nutrient relationships were defined using the clustered XRPD patterns and corresponding measurements of total and/or extractable (Mehlich-3) nutrient concentrations (B, Mg, K, Ca, Mn, Fe, Ni, Cu and Zn) in combination with log-ratio compositional data analysis. Fe/Al/Ti/Mn-(hydr)oxides and feldspars were found to be the primary control of total nutrient concentrations, whereas 2:1 phyllosilicates were the main source of all extractable nutrients except for Fe and Zn. Kaolin minerals were the most abundant phyllosilicate group within the dataset but did not represent a nutrient source, which reflects the lack of nutrients within their chemical composition and their low cation exchange capacity. Results highlight how the mineral composition controls the total nutrient reserves and their phyto-availability in soils of sub-Saharan Africa. The typical characterisation of soils and their parent material based on the clay particle size fraction (i.e. texture) and/or the overall silica component (i.e. acid and basic rock types) alone may therefore mask the intricacies of mineral contributions to soil nutrient concentrations.

Meta-analysis of heavy metal effects on soil enzyme activities.

Enzyme activities (EAs) respond to contamination in several ways depending on the chemical form and content of heavy metals and metalloids (HMs) and their interactions with various soil properties. A systematic and mechanistic understanding of EA responses to HM contamination in soil is necessary for predicting the consequences for nutrient availability and the cycling of carbon (C), nitrogen (N), phosphorus (P) and sulphur (S). In this study, a meta-analysis based on 671 observations found the activities of seven enzymes to decrease in response to soil contamination with Pb, Zn, Cd, Cu and As. HM contamination linearly reduced the activities of all enzymes in the following order: arylsulfatase > dehydrogenase > ß-glucosidase > urease > acid phosphatase > alkaline phosphatase > catalase. The activities of two endoenzymes: arylsulfatase (partly as exoenzyme) and dehydrogenase were reduced by 72% and 64%, respectively. These reductions were two times greater than of exoenzymes: ß-glucosidase, urease, acid phosphatase, alkaline phosphatase and catalase (partly endoenzyme). This reflects the much stronger impact of HMs on living microorganisms and their endoenzymes than on extracellular enzymes stabilized on clay minerals and organic matter. Increasing clay content weakened the negative effects of HM contamination on EAs. All negative effects of HMs on EAs decreased with soil depth because HMs remain mainly in the topsoil. EAs involved in the cycling of C and S were more affected by HMs than the enzymes associated with the cycling of N and P. Consequently, HM contamination may alter the stoichiometry of C, N, P and S released by enzymatic decomposition of organic compounds that consequently affect microbial community structure and activity.

Pre-treatment of soil X-ray powder diffraction data for cluster analysis.

X-ray powder diffraction (XRPD) is widely applied for the qualitative and quantitative analysis of soil mineralogy. In recent years, high-throughput XRPD has resulted in soil XRPD datasets containing thousands of samples. The efforts required for conventional approaches of soil XRPD data analysis are currently restrictive for such large data sets, resulting in a need for computational methods that can aid in defining soil property - soil mineralogy relationships. Cluster analysis of soil XRPD data represents a rapid method for grouping data into discrete classes based on mineralogical similarities, and thus allows for sets of mineralogically distinct soils to be defined and investigated in greater detail. Effective cluster analysis requires minimisation of sample-independent variation and maximisation of sample-dependent variation, which entails pre-treatment of XRPD data in order to correct for common aberrations associated with data collection. A 24 factorial design was used to investigate the most effective data pre-treatment protocol for the cluster analysis of XRPD data from 12 African soils, each analysed once by five different personnel. Sample-independent effects of displacement error, noise and signal intensity variation were pre-treated using peak alignment, binning and scaling, respectively. The sample-dependent effect of strongly diffracting minerals overwhelming the signal of weakly diffracting minerals was pre-treated using a square-root transformation. Without pre-treatment, the 60 XRPD measurements failed to provide informative clusters. Pre-treatment via peak alignment, square-root transformation, and scaling each resulted in significantly improved partitioning of the groups (p < 0.05). Data pre-treatment via binning reduced the computational demands of cluster analysis, but did not significantly affect the partitioning (p > 0.1). Applying all four pre-treatments proved to be the most suitable protocol for both non-hierarchical and hierarchical cluster analysis. Deducing such a protocol is considered a prerequisite to the wider application of cluster analysis in exploring soil property - soil mineralogy relationships in larger datasets.

Alterations of the nigrostriatal pathway in a 6-OHDA rat model of Parkinson's disease evaluated with multimodal MRI.

Parkinson's disease is characterized by neurodegeneration of the dopaminergic neurons in the substantia nigra pars compacta. The 6-hydroxydopamine (6-OHDA) rat model has been used to study neurodegeneration in the nigro-striatal dopaminergic system. The goal of this study was to evaluate the reliability of diffusion MRI and resting-state functional MRI biomarkers in monitoring neurodegeneration in the 6-OHDA rat model assessed by quantitative histology. We performed a unilateral injection of 6-OHDA in the striatum of Sprague Dawley rats to produce retrograde degeneration of the dopamine neurons in the substantia nigra pars compacta. We carried out a longitudinal study with a multi-modal approach combining structural and functional MRI together with quantitative histological validation to follow the effects of the lesion. Functional and structural connectivity were assessed in the brain of 6-OHDA rats and sham rats (NaCl injection) at 3 and 6 weeks post-lesioning using resting-state functional MRI and diffusion-weighted. Our results showed (i) increased functional connectivity in ipsi- and contra-lesioned regions of the cortico-basal ganglia network pathway including the motor cortex, the globus pallidus, and the striatum regions at 3 weeks; (ii) increased fractional anisotropy (FA) in the ipsi- and contralateral striatum of the 6-OHDA group at 3 weeks, and increased axial diffusivity (AD) and mean diffusivity in the ipsilateral striatum at 6 weeks; (iii) a trend for increased FA in both substantia nigra of the 6-OHDA group at 3 weeks. Optical density measurements of tyrosine-hydroxylase (TH) staining of the striatum showed good correlations with the FA and AD measurements in the striatum. No correlations were found between the number of TH-stained dopaminergic neurons and MRI measurements in the substantia nigra. This study suggested that (i) FA and AD were reliable biomarkers to evaluate neurodegeneration in the cortico-basal ganglia network of the 6-OHDA model, (ii) diffusion MRI and resting-state functional MRI (rsfMRI) were not sensitive enough to detect changes in the substantia nigra in this model.

A slow-cooling-rate in situ cell for long-duration studies of mineral precipitation in cold aqueous environments on Earth and other planetary bodies.

Liquid oceans and ice caps, along with ice crusts, have long been considered defining features of the Earth, but space missions and observations have shown that they are in fact common features among many of the solar system's outer planets and their satellites. Interactions with rock-forming materials have produced saline oceans not dissimilar in many respects to those on Earth, where mineral precipitation within frozen seawater plays a significant role in both determining global properties and regulating the environment in which a complex ecosystem of extremophiles exists. Since water is considered an essential ingredient for life, the presence of oceans and ice on other solar system bodies is of great astrobiological interest. However, the details surrounding mineral precipitation in freezing environments are still poorly constrained, owing to the difficulties of sampling and ex situ preservation for laboratory analysis, meaning that predictive models have limited empirical underpinnings. To address this, the design and performance characterization of a transmission-geometry sample cell for use in long-duration synchrotron X-ray powder diffraction studies of in situ mineral precipitation from aqueous ice-brine systems are presented. The cell is capable of very slow cooling rates (e.g. 0.3°C per day or less), and its performance is demonstrated with the results from a year-long study of the precipitation of the hydrated magnesium sulfate phase meridianiite (MgSO4·11H2O) from the MgSO4-H2O system. Evidence from the Mars Rover mission suggests that this hydrated phase is widespread on the present-day surface of Mars. However, as well as the predicted hexagonal ice and meridianiite phases, an additional hydrated sulfate phase and a disordered phase are observed.

Symptomatic Acute Hepatitis C Infection Following a Single Episode of Unprotected Sexual Intercourse.

A previously healthy 23-year-old MSM presented with jaundice, systemic upset, and rash 2 months after a single episode of unprotected sexual intercourse. Liver biochemistry was grossly deranged, with markedly elevated transaminases and hyperbilirubinaemia. Serology was positive for genotype 1a hepatitis C virus (HCV) and in the absence of other causes, acute HCV infection was suspected. He was subsequently successfully treated with pegylated interferon and ribavirin for 24 weeks and made a full clinical and biochemical recovery.

Deletion of protein tyrosine phosphatase 1b in proopiomelanocortin neurons reduces neurogenic control of blood pressure and protects mice from leptin- and sympatho-mediated hypertension.

Protein tyrosine phosphatase 1b (Ptp1b), which represses leptin signaling, is a promising therapeutic target for obesity. Genome wide deletion of Ptp1b, increases leptin sensitivity, protects mice from obesity and diabetes, but alters cardiovascular function by increasing blood pressure (BP). Leptin-control of metabolism is centrally mediated and involves proopiomelanocortin (POMC) neurons. Whether these neurons contribute to leptin-mediated increases in BP remain unclear. We hypothesized that increasing leptin signaling in POMC neurons with Ptp1b deletion will sensitize the cardiovascular system to leptin and enhance neurogenic control of BP. We analyzed the cardiovascular phenotype of Ptp1b+/+ and POMC-Ptp1b-/- mice, at baseline and after 7 days of leptin infusion or sympatho-activation with phenylephrine. POMCPtp1b deletion did not alter baseline cardiovascular hemodynamics (BP, heart rate) but reduced BP response to ganglionic blockade and plasma catecholamine levels that suggests a decreased neurogenic control of BP. In contrast, POMC-Ptp1b deletion increased vascular adrenergic reactivity and aortic α-adrenergic receptors expression. Chronic leptin treatment reduced vascular adrenergic reactivity and blunted diastolic and mean BP increases in POMC-Ptp1b-/- mice only. Similarly POMC-Ptp1b-/- mice exhibited a blunted increased in diastolic and mean BP accompanied by a gradual reduction in adrenergic reactivity in response to chronic vascular sympatho-activation with phenylephrine. Together these data rule out our hypothesis but suggest that deletion of Ptp1b in POMC neurons protects from leptin- and sympatho-mediated increases in BP. Vascular adrenergic desensitization appears as a protective mechanism against hypertension, and POMC-Ptp1b as a key therapeutic target for the treatment of metabolic and cardiovascular dysfunctions associated with obesity.

Smart molecularly imprinted polymers: recent developments and applications.

The use of the molecular imprinting technique to produce polymers with high specificity for a given "molecular template" has undergone a rapid and expansive evolution since the inception of the idea over half a century ago. It was only a matter of time before the seemingly inevitable "marriage" of this concept with another modern research obsession, the generation of "smart" polymers, capable of reacting quickly, accurately and reproducibly to changes in their environment. Many advances have since been made, concerning the quality and diversity of these systems and polymers responsive to temperature, pH and a host of other environmental cues now exist. This article provides a succinct overview of the process and outcomes of "smart" molecular imprinting, followed by a detailed assessment of recent developments and applications in such field.