ONT read assembly of the black rhino genome.

Objectives: The black rhinoceros (Diceros bicornis) is an endangered mammal for which a captive breeding program is part of the conservation effort. Black rhinos in zoo's often suffer from chronic infections and heamochromatosis. Furthermore, breeding is hampered by low male fertility.

Correlated x-ray fluorescence and ptychographic nano-tomography on Rembrandt's reveals unknown lead "layer".

, one of the most famous masterpieces by Rembrandt, is the subject of a large research and conservation project. For the conservation treatment, it is of great importance to understand its current condition. Correlated nano-tomography using x-ray fluorescence and ptychography revealed a-so far unknown-lead-containing "layer", which likely acts as a protective impregnation layer applied on the canvas before the quartz-clay ground was applied.

Sunlight Powered Continuous Flow Reverse Water Gas Shift Process Using a Plasmonic Au/TiO Nanocatalyst.

The continuous flow reverse water gas shift (rWGS) process was efficiently catalyzed by a plasmonic Au/TiO nanocatalyst using sunlight as sole and sustainable energy source. The influence of the catalyst bed thickness on the CO production rate was studied, and three different catalytic regimes were identified as direct plasmon catalysis (DPC), shielded plasmon catalysis (SPC) and unused plasmon catalysis (UPC). The CO  : H ratio was optimized to 4 : 1 and a maximum CO production rate of 7420 mmol ⋅ m  ⋅ h was achieved under mild reaction conditions (p=3.

A Ziegler-type spherical cap model reveals early stage ethylene polymerization growth versus catalyst fragmentation relationships.

Polyolefin catalysts are characterized by their hierarchically complex nature, which complicates studies on the interplay between the catalyst and formed polymer phases. Here, the missing link in the morphology gap between planar model systems and industrially relevant spherical catalyst particles is introduced through the use of a spherical cap Ziegler-type catalyst model system for the polymerization of ethylene. More specifically, a moisture-stable LaOCl framework with enhanced imaging contrast has been designed to support the TiCl pre-active site, which could mimic the behaviour of the highly hygroscopic and industrially used MgCl framework.

Tandem catalysis with double-shelled hollow spheres.

Metal-zeolite composites with metal (oxide) and acid sites are promising catalysts for integrating multiple reactions in tandem to produce a wide variety of wanted products without separating or purifying the intermediates. However, the conventional design of such materials often leads to uncontrolled and non-ideal spatial distributions of the metal inside/on the zeolites, limiting their catalytic performance. Here we demonstrate a simple strategy for synthesizing double-shelled, contiguous metal oxide@zeolite hollow spheres (denoted as MO@ZEO DSHSs) with controllable structural parameters and chemical compositions.

Heterogeneity in the Fragmentation of Ziegler Catalyst Particles during Ethylene Polymerization Quantified by X-ray Nanotomography.

Ziegler-type catalysts are the grand old workhorse of the polyolefin industry, yet their hierarchically complex nature complicates polymerization activity-catalyst structure relationships. In this work, the degree of catalyst framework fragmentation of a high-density polyethylene (HDPE) Ziegler-type catalyst was studied using ptychography X-ray-computed nanotomography (PXCT) in the early stages of ethylene polymerization under mild reaction conditions. An ensemble consisting of 434 fully reconstructed ethylene prepolymerized Ziegler catalyst particles prepared at a polymer yield of 3.

Visualizing defects and pore connectivity within metal-organic frameworks by X-ray transmission tomography.

Metal-Organic Frameworks (MOFs) have the potential to change the landscape of molecular separations in chemical processes owing to their ability of selectively binding molecules. Their molecular sorting properties generally rely on the micro- and meso-pore structure, as well as on the presence of coordinatively unsaturated sites that interact with the different chemical species present in the feed. In this work, we show a first-of-its-kind tomographic imaging of the crystal morphology of a metal-organic framework by means of transmission X-ray microscopy (TXM), including a detailed data reconstruction and processing approach.

Influence of Metal-Alkyls on Early-Stage Ethylene Polymerization over a Cr/SiO Phillips Catalyst: A Bulk Characterization and X-ray Chemical Imaging Study.

The Cr/SiO Phillips catalyst has taken a central role in ethylene polymerization since its invention in 1953. The uniqueness of this catalyst is related to its ability to produce broad molecular weight distribution (MWD) PE materials as well as that no co-catalysts are required to attain activity. Nonetheless, co-catalysts in the form of metal-alkyls can be added for scavenging poisons, enhancing catalyst activity, reducing the induction period, and tailoring polymer characteristics.

Correlated X-ray Ptychography and Fluorescence Nano-Tomography on the Fragmentation Behavior of an Individual Catalyst Particle during the Early Stages of Olefin Polymerization.

A combination of X-ray ptychography and X-ray fluorescence tomography (XRF) has been used to study the fragmentation behavior of an individual Ziegler-Natta catalyst particle, ∼40 μm in diameter, in the early stages of propylene polymerization with submicron spatial resolution. The electron density signal obtained from X-ray ptychography gives the composite phases of the Ziegler-Natta catalyst particle fragments and isotactic polypropylene, while 3-D XRF visualizes multiple isolated clusters, rich in Ti, of several microns in size. The radial distribution of Ti species throughout the polymer-catalyst composite particle shows that the continuous bisection fragmentation model is the main contributor to the fragmentation pathway of the catalyst particle as a whole.

The Effects of Sindbis Viral Vectors on Neuronal Function.

Viral vectors are attractive tools to express genes in neurons. Transduction of neurons with a recombinant, replication-deficient Sindbis viral vector is a method of choice for studying the effects of short-term protein overexpression on neuronal function. However, to which extent Sindbis by itself may affect neurons is not fully understood.

Transcriptome analysis of normal-appearing white matter reveals cortisol- and disease-associated gene expression profiles in multiple sclerosis.

Inter-individual differences in cortisol production by the hypothalamus-pituitary-adrenal (HPA) axis are thought to contribute to clinical and pathological heterogeneity of multiple sclerosis (MS). At the same time, accumulating evidence indicates that MS pathogenesis may originate in the normal-appearing white matter (NAWM). Therefore, we performed a genome-wide transcriptional analysis, by Agilent microarray, of post-mortem NAWM of 9 control subjects and 18 MS patients to investigate to what extent gene expression reflects disease heterogeneity and HPA-axis activity.

Capturing the Genesis of an Active Fischer-Tropsch Synthesis Catalyst with Operando X-ray Nanospectroscopy.

A state-of-the-art operando spectroscopic technique is applied to Co/TiO catalysts, which account for nearly half of the world's transportation fuels produced by Fischer-Tropsch catalysis. This allows determination of, at a spatial resolution of approximately 50 nm, the interdependence of formed hydrocarbon species in the inorganic catalyst. Observed trends show intra- and interparticular heterogeneities previously believed not to occur in particles under 200 μm.

Genesis of MgCl -based Ziegler-Natta Catalysts as Probed with Operando Spectroscopy.

Ziegler-Natta catalysts for olefin polymerization are intrinsically complex multi-component systems. The genesis of the active sites involves several simultaneous and sequential steps, making the individual steps and interconnections difficult to be unraveled in an unambiguous manner. In this work, we combine X-ray diffraction and spectroscopy to probe each step of the birth and life of a MgCl -based Ziegler-Natta catalyst, namely the formation of high surface area MgCl by dealcoholation of an alcoholate precursor, the TiCl grafting, and the subsequent activation by triethylaluminum as co-catalyst.

Repulsive Guidance Molecule a (RGMa) Induces Neuropathological and Behavioral Changes That Closely Resemble Parkinson's Disease.

Repulsive guidance molecule member a (RGMa) is a membrane-associated or released guidance molecule that is involved in axon guidance, cell patterning, and cell survival. In our previous work, we showed that RGMa is significantly upregulated in the substantia nigra of patients with Parkinson's disease. Here we demonstrate the expression of RGMa in midbrain human dopaminergic (DA) neurons.

MicroRNA-132 and early growth response-1 in nucleus basalis of Meynert during the course of Alzheimer's disease.

The cholinergic nucleus basalis of Meynert, which is important for memory functions, shows neuronal activation ('up-phase') during the early stages of Alzheimer's disease and neurodegeneration ('down-phase') in later stages of Alzheimer's disease. MicroRNA-132 (miR-132) and the transcription factor early growth response-1 (EGR1) were proposed as possible candidate molecules regulating such an up-down activity pattern of the nucleus basalis of Meynert during the course of Alzheimer's disease, as they both show this up-down pattern of expression in the prefrontal cortex during the course of Alzheimer's disease. Not only do these two molecules stimulate synaptic activity and plasticity, they are also involved in Alzheimer's disease pathology and might, in addition, affect cholinergic function.

Comparison of Mouse and Human Retinal Pigment Epithelium Gene Expression Profiles: Potential Implications for Age-Related Macular Degeneration.

Background: The human retinal pigment epithelium (RPE) plays an important role in the pathogenesis of age related macular degeneration (AMD). AMD is the leading cause of blindness worldwide. There is currently no effective treatment available.

Loss of GPR3 reduces the amyloid plaque burden and improves memory in Alzheimer's disease mouse models.

The orphan G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor (GPCR) GPR3 regulates activity of the γ-secretase complex in the absence of an effect on Notch proteolysis, providing a potential therapeutic target for Alzheimer's disease (AD). However, given the vast resources required to develop and evaluate any new therapy for AD and the multiple failures involved in translational research, demonstration of the pathophysiological relevance of research findings in multiple disease-relevant models is necessary before initiating costly drug development programs. We evaluated the physiological consequences of loss of Gpr3 in four AD transgenic mouse models, including two that contain the humanized murine Aβ sequence and express similar amyloid precursor protein (APP) levels as wild-type mice, thereby reducing potential artificial phenotypes.

Stratified gene expression analysis identifies major amyotrophic lateral sclerosis genes.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of motor neurons resulting in progressive paralysis. Gene expression studies of ALS only rarely identify the same gene pathways as gene association studies. We hypothesized that analyzing tissues by matching on degree of disease severity would identify different patterns of gene expression from a traditional case-control comparison.

Increasing membrane cholesterol of neurons in culture recapitulates Alzheimer's disease early phenotypes.

Background: It is suspected that excess of brain cholesterol plays a role in Alzheimer's disease (AD). Membrane-associated cholesterol was shown to be increased in the brain of individuals with sporadic AD and to correlate with the severity of the disease. We hypothesized that an increase of membrane cholesterol could trigger sporadic AD early phenotypes.

Storm before the quiet: neuronal hyperactivity and Aβ in the presymptomatic stages of Alzheimer's disease.

Neuronal activity directly promotes the production and secretion of amyloid β (Aβ). Interestingly, neuronal hyperactivity can be observed in presymptomatic stages of both sporadic and familial Alzheimer's disease (AD) and in several AD mouse models. In this review, we will highlight the recent evidence for neuronal hyperactivity before or during the onset of cognitive defects in mild cognitive impairment.

Isolation of glia from Alzheimer's mice reveals inflammation and dysfunction.

Reactive astrocytes and microglia are associated with amyloid plaques in Alzheimer's disease (AD). Yet, not much is known about the molecular alterations underlying this reactive phenotype. To get an insight into the molecular changes underlying AD induced astrocyte and microglia reactivity, we performed a transcriptional analysis on acutely isolated astrocytes and microglia from the cortex of aged controls and APPswe/PS1dE9 AD mice.

Microarray and morphological analysis of early postnatal CRB2 mutant retinas on a pure C57BL/6J genetic background.

In humans, the Crumbs homologue-1 (CRB1) gene is mutated in progressive types of autosomal recessive retinitis pigmentosa and Leber congenital amaurosis. The severity of the phenotype due to human CRB1 or mouse Crb1 mutations is dependent on the genetic background. Mice on C57BL/6J background with Crb1 mutations show late onset of retinal spotting phenotype or no phenotype.

Reduced expression of hsa-miR-27a-3p in CSF of patients with Alzheimer disease.

Objective: We evaluated microRNAs (miRNAs) as potential biomarkers for Alzheimer disease (AD) by analyzing the expression level of miRNAs in CSF of patients with AD dementia and nonaffected control subjects.

Methods: Using quantitative PCR, we profiled the expression level of 728 miRNAs in CSF of nonaffected control subjects and patients with clinically ascertained AD dementia, and we further compared the expression level of candidate miRNAs in 37 control subjects and 35 patients with AD dementia.

Results: The level of hsa-miR-27a-3p in CSF is reduced in patients with dementia due to AD in 2 different cohorts of subjects (cohort 1: p = 0.

Early molecular changes in Alzheimer disease: can we catch the disease in its presymptomatic phase?

Alzheimer disease (AD) is the most common form of dementia and characterized by deposition of amyloid-β (Aβ) plaques, neurofibrillary tangles consisting of hyperphosphorylated tau, atrophy, and progressive neurodegeneration. While the familial, early onset form of AD is known to be caused by specific mutations in genes encoding presenilin 1, presenilin 2, or amyloid-β protein precursor, the underlying mechanisms leading to the development of sporadic AD are still not known. The major risk factors are, however, aging and APOE ε4.