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result(s) for
"Bauer, Adriano"
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Cobalt-electrocatalytic HAT for functionalization of unsaturated C–C bonds
2022
The study and application of transition metal hydrides (TMHs) has been an active area of chemical research since the early 1960s
1
, for energy storage, through the reduction of protons to generate hydrogen
2
,
3
, and for organic synthesis, for the functionalization of unsaturated C–C, C–O and C–N bonds
4
,
5
. In the former instance, electrochemical means for driving such reactivity has been common place since the 1950s
6
but the use of stoichiometric exogenous organic- and metal-based reductants to harness the power of TMHs in synthetic chemistry remains the norm. In particular, cobalt-based TMHs have found widespread use for the derivatization of olefins and alkynes in complex molecule construction, often by a net hydrogen atom transfer (HAT)
7
. Here we show how an electrocatalytic approach inspired by decades of energy storage research can be made use of in the context of modern organic synthesis. This strategy not only offers benefits in terms of sustainability and efficiency but also enables enhanced chemoselectivity and distinct, tunable reactivity. Ten different reaction manifolds across dozens of substrates are exemplified, along with detailed mechanistic insights into this scalable electrochemical entry into Co–H generation that takes place through a low-valent intermediate.
A perspective is given on how an electrocatalytic approach, inspired by decades of energy storage studies, can be used in the context of efficient cobalt-hydride generation with a variety of applications in modern organic synthesis.
Journal Article
Ventral hippocampal OLM cells control type 2 theta oscillations and response to predator odor
2018
Dorsal and ventral hippocampus regions exert cognition and emotion-related functions, respectively. Since both regions display rhythmic activity, specific neural oscillatory pacemakers may underlie their functional dichotomy. Type 1 theta oscillations are independent of cholinergic transmission and are observed in the dorsal hippocampus during movement and exploration. In contrast, type 2 theta depends on acetylcholine and appears when animals are exposed to emotionally laden contexts such as a predator presence. Despite its involvement in emotions, type 2 theta has not been associated with the ventral hippocampus. Here, we show that optogenetic activation of oriens-lacunosum moleculare (OLM) interneurons in the ventral hippocampus drives type 2 theta. Moreover, we found that type 2 theta generation is associated with increased risk-taking behavior in response to predator odor. These results demonstrate that two theta oscillations subtypes originate in the two hippocampal regions that predominantly underlie either cognitive or emotion-related functions.
There are two subtypes of hippocampal theta oscillations that differ in frequency range, pharmacology, and behavioural correlates. Here, the authors report that activity of OLM interneurons in the ventral hippocampus mediates type 2 theta, associated with increased risk-taking in the presence of predator threat.
Journal Article
De novo protein design by citizen scientists
2019
Online citizen science projects such as GalaxyZoo
1
, Eyewire
2
and Phylo
3
have proven very successful for data collection, annotation and processing, but for the most part have harnessed human pattern-recognition skills rather than human creativity. An exception is the game EteRNA
4
, in which game players learn to build new RNA structures by exploring the discrete two-dimensional space of Watson–Crick base pairing possibilities. Building new proteins, however, is a more challenging task to present in a game, as both the representation and evaluation of a protein structure are intrinsically three-dimensional. We posed the challenge of de novo protein design in the online protein-folding game Foldit
5
. Players were presented with a fully extended peptide chain and challenged to craft a folded protein structure and an amino acid sequence encoding that structure. After many iterations of player design, analysis of the top-scoring solutions and subsequent game improvement, Foldit players can now—starting from an extended polypeptide chain—generate a diversity of protein structures and sequences that encode them in silico. One hundred forty-six Foldit player designs with sequences unrelated to naturally occurring proteins were encoded in synthetic genes; 56 were found to be expressed and soluble in
Escherichia coli
, and to adopt stable monomeric folded structures in solution. The diversity of these structures is unprecedented in de novo protein design, representing 20 different folds—including a new fold not observed in natural proteins. High-resolution structures were determined for four of the designs, and are nearly identical to the player models. This work makes explicit the considerable implicit knowledge that contributes to success in de novo protein design, and shows that citizen scientists can discover creative new solutions to outstanding scientific challenges such as the protein design problem.
Proteins designed de novo by players of the online protein-folding game Foldit can be expressed in
Escherichia coli
and adopt the designed structure in solution.
Journal Article
EANM guideline for ventilation/perfusion single-photon emission computed tomography (SPECT) for diagnosis of pulmonary embolism and beyond
by
Schümichen, Carl
,
Verberne, Hein J
,
Delgado Bolton, Roberto C
in
Chronic obstructive pulmonary disease
,
Computed tomography
,
Congestive heart failure
2019
These guidelines update the previous EANM 2009 guidelines on the diagnosis of pulmonary embolism (PE). Relevant new aspects are related to (a) quantification of PE and other ventilation/perfusion defects; (b) follow-up of patients with PE; (c) chronic PE; and (d) description of additional pulmonary physiological changes leading to diagnoses of left ventricular heart failure (HF), chronic obstructive pulmonary disease (COPD) and pneumonia. The diagnosis of PE should be reported when a mismatch of one segment or two subsegments is found. For ventilation, Technegas or krypton gas is preferred over diethylene triamine pentaacetic acid (DTPA) in patients with COPD. Tomographic imaging with V/PSPECT has higher sensitivity and specificity for PE compared with planar imaging. Absence of contraindications makes V/PSPECT an essential method for the diagnosis of PE. When V/PSPECT is combined with a low-dose CT, the specificity of the test can be further improved, especially in patients with other lung diseases. Pitfalls in V/PSPECT interpretation are discussed. In conclusion, V/PSPECT is strongly recommended as it accurately establishes the diagnosis of PE even in the presence of diseases like COPD, HF and pneumonia and has no contraindications.
Journal Article
Phenolic Analysis and In Vitro Biological Activity of Red Wine, Pomace and Grape Seeds Oil Derived from Vitis vinifera L. cv. Montepulciano d’Abruzzo
by
Fernández-de Córdova, Maria Luisa
,
Scioli, Giuseppe
,
Castillo-López, R.
in
alpha-amylase
,
Alzheimer's disease
,
anti-inflammatory activity
2021
Grape pomace is commonly considered a waste product of monovarietal red wine production. Methods: HPLC-DAD analysis was performed to determine the polyphenol and flavonoid contents of all the extracts obtained from Montepulciano d’Abruzzo red wine and grape skins whereas, GC-MS was applied to the determination of fatty acid composition in grape seeds oil. Biological characterization involves antioxidant and antimicrobial assays for all the extracts and seeds oil; Their ability to inhibit α-glucosidase, α-amylase, α-tyrosinase, and ChE enzymes was also detected, together with anti-inflammatory activity on wine, grape skin extracts, and seeds oil by lipoxygenase (5-LOX) and LPS-stimulated macrophage release assays. Data indicate significative polyphenols content (199.31 ± 7.21 mgGAE/g), antioxidant (CUPRAC assay (1036.98 mgTE/g)), enzymatic inhibition (α-tyrosinase: 151.30 ± 1.20 mgKAE/g) and anti-inflammatory activities for wine-organic extract 2, while the antimicrobial activity of grape skin decoction is higher than those reported by wine extracts on three bacterial strains. Interestingly only dealcoholized wine and wine-aqueous extract exerts inhibitory effects on α-glucosidase (20.62 ± 0.23 mmolACAE/g and 19.81 ± 0.03 mmolACAE/g, respectively), while seeds oil is rich in oleic and linoleic acids. These results confirm the strong antioxidant properties of Montepulciano d’Abruzzo grape pomace, suggesting the potential use of this waste product as functional food supplements in the human diet and in cosmeceutics.
Journal Article
Does the COPD assessment test reflect functional status in patients with COPD?
by
Gulart, Aline Almeida
,
Cani, Katerine Cristhine
,
Matte, Darlan Laurício
in
Activities of Daily Living
,
Aged
,
Body measurements
2017
The aim of this study was to investigate whether the chronic obstructive pulmonary disease (COPD) assessment test (CAT) reflects the functional status of patients with COPD. Forty-seven patients underwent anthropometric assessment, spirometry, the 6-minute walk test (6MWT), the Glittre-activity of daily living (ADL) test (TGlittre), the London Chest ADL (LCADL) scale, and the CAT. The total score of the CAT correlated with 6MWT distance, TGlittre time spent, and LCADL%total (r = −0.56, 0.52, and 0.78, respectively; p < 0.05 for all). There was significant difference in 6MWT distance (490 ± 85.4 m vs. 387 ± 56.8 m), TGlittre time spent (3.67 ± 1.07 min vs. 5.03 ± 1.32 min), and LCADL%total (24.2 ± 3.02% vs. 44.4 ± 13.3%) between the low and high impacts of COPD on health status (respectively, p < 0.05 for all) as well as in the LCADL%total between medium and high impact of COPD on health status (31.3 ± 7.35% vs. 44.4 ± 13.3%; p = 0.001). In conclusion, the CAT reflects the functional status of patients with COPD.
Journal Article
Inpatient Initiation of Oral Treprostinil in an Academic Medical System
2020
PurposeClinicians may transition patients on parenteral or inhaled prostacyclins to oral treprostinil for ease of use or to avoid adverse effects related to parenteral therapy. However, few data are available to guide these transitions in inpatients. The purpose of this analysis is to describe the inpatient initiation of oral treprostinil at an academic medical system.MethodsThis is a retrospective cohort analysis of patients newly initiated on oral treprostinil at Cleveland Clinic Heath System from 2015 to 2017. Demographic information regarding pulmonary arterial hypertension (PAH) history and previous PAH therapies were recorded. Outcomes evaluated included doses of oral treprostinil utilized, adverse effects related to therapy, and measures of clinical and functional status before and after the initiation of oral treprostinil.ResultsOverall, 29 patients were prescribed oral treprostinil, of which 15 patients were included in the analysis. Common reasons for initiation of oral treprostinil included disease progression (6, 40%) and patient desire (4, 25%). The median duration of transition/initiation of oral treprostinil was 4 days (range, 3–11 days). Median daily dose of oral treprostinil on day 1 of initiation was 2 mg (0.25–4 mg). By day 7, median daily dose was 15 mg (0.75–27.75 mg). Common adverse effects related to therapy were gastrointestinal (7, 47%) and headache (4, 27%). No patients required discontinuation of oral treprostinil due to adverse effects within 90 days of initiation.ConclusionInpatient initiation/transition to oral treprostinil was relatively well tolerated. Future studies should evaluate clinical outcomes surrounding the transitioning to oral treprostinil.
Journal Article
Cystatin F is a biomarker of prion pathogenesis in mice
by
Dietmeier, Klaus
,
Kallweit, Ulf
,
Martin, Roland
in
Alzheimer's disease
,
Animal models
,
Animals
2017
Misfolding of the cellular prion protein (PrPC) into the scrapie prion protein (PrPSc) results in progressive, fatal, transmissible neurodegenerative conditions termed prion diseases. Experimental and epidemiological evidence point toward a protracted, clinically silent phase in prion diseases, yet there is no diagnostic test capable of identifying asymptomatic individuals incubating prions. In an effort to identify early biomarkers of prion diseases, we have compared global transcriptional profiles in brains from pre-symptomatic prion-infected mice and controls. We identified Cst7, which encodes cystatin F, as the most strongly upregulated transcript in this model. Early and robust upregulation of Cst7 mRNA levels and of its cognate protein was validated in additional mouse models of prion disease. Surprisingly, we found no significant increase in cystatin F levels in both cerebrospinal fluid or brain parenchyma of patients with Creutzfeldt-Jakob disease compared to Alzheimer's disease or non-demented controls. Our results validate cystatin F as a useful biomarker of early pathogenesis in experimental models of prion disease, and point to unexpected species-specific differences in the transcriptional responses to prion infections.
Journal Article
Femtosecond pulse pair distribution functions at MID at the European XFEL
by
Bauer, Robert P.C.
,
Paulus, Michael
,
Grisenti, Robert E.
in
Distribution functions
,
Femtosecond pulses
,
Field of view
2025
Pair distribution functions from individual femtosecond X-ray pulses have the potential to elucidate the structure of transient states in matter, such as those found in liquid systems. To demonstrate this possibility an experiment was conducted at the Materials Imaging and Dynamics instrument of European X-ray Free Electron Laser Facility. We utilized the large field of view detector configuration, exploiting single high-flux X-ray pulses of femtosecond duration at 23 keV photon energy. After deconvolution from the pattern termination function, we show here pair distribution functions of liquid water at approximately 260 K. These results demonstrate that current X-ray free electron laser methods can acquire pair distribution functions on the femtosecond timescale that have potential to capture transient state of liquids.
Journal Article
Virus-Induced Gene Silencing of Plastidial Soluble Inorganic Pyrophosphatase Impairs Essential Leaf Anabolic Pathways and Reduces Drought Stress Tolerance in Nicotiana benthamiana
by
van der Merwe, Margaretha J
,
Lloyd, James R
,
Bauer, Rolene
in
abscisic acid
,
Adaptation, Physiological
,
BIOCHEMICAL PROCESSES AND MACROMOLECULAR STRUCTURES
2010
The role of pyrophosphate in primary metabolism is poorly understood. Here, we report on the transient down-regulation of plastid-targeted soluble inorganic pyrophosphatase in Nicotiana benthamiana source leaves. Physiological and metabolic perturbations were particularly evident in chloroplastic central metabolism, which is reliant on fast and efficient pyrophosphate dissipation. Plants lacking plastidial soluble inorganic pyrophosphatase (psPPase) were characterized by increased pyrophosphate levels, decreased starch content, and alterations in chlorophyll and carotenoid biosynthesis, while constituents like amino acids (except for histidine, serine, and tryptophan) and soluble sugars and organic acids (except for malate and citrate) remained invariable from the control. Furthermore, translation of Rubisco was significantly affected, as observed for the amounts of the respective subunits as well as total soluble protein content. These changes were concurrent with the fact that plants with reduced psPPase were unable to assimilate carbon to the same extent as the controls. Furthermore, plants with lowered psPPase exposed to mild drought stress showed a moderate wilting phenotype and reduced vitality, which could be correlated to reduced abscisic acid levels limiting stomatal closure. Taken together, the results suggest that plastidial pyrophosphate dissipation through psPPase is indispensable for vital plant processes.
Journal Article