297 research outputs found
Recovering pyramid WS gain in non-common path aberration correction mode via deformable lens
It is by now well known that pyramid based wavefront sensors, once in closed
loop, have the capability to improve more and more the gain as the reference
natural star image size is getting smaller on the pyramid pin. Especially in
extreme adaptive optics applications, in order to correct the non-common path
aberrations between the scientific and sensing channel, it is common use to
inject a certain amount of offset wavefront deformation into the DM(s),
departing at the same time the pyramid from the optimal working condition. In
this paper we elaborate on the possibility to correct the low order non-common
path aberrations at the pyramid wavefront sensor level by means of an adaptive
refractive lens placed on the optical path before the pyramid itself, allowing
the mitigation of the gain loss
Evaluation of synthetic substituted 1,2-dioxanes as novel agents against human leishmaniasis
The treatment of human leishmaniasis is currently based on few compounds that are highly toxic, expensive and have a high rate of treatment failure. A number of recent studies on new drugs focuses on natural or semi-synthetic compounds. Among them, the endoperoxide artemisinin, extracted from Artemisia annua, and some of its derivatives have shown leishmanicidal activity. In the present work, a series of structurally simple, fully synthetic 1,2-dioxanes were evaluated for in vitro antileishmanial activity against promastigotes of Leishmania donovani; the cytotoxicity for mammalian cells was also assessed. The six most promising compounds in terms of activity and selectivity were further investigated for their antileishmanial activity on the promastigote forms of L. tropica, L. major and L. infantum and against L. donovani amastigotes. The good performance in terms of potency and selectivity makes these six hits promising candidates for a preliminary lead optimization as antileishmanial agents
Towards a More Sustainable Photocatalyzed α-Arylation of Amines: Green Solvents, Catalyst Recycling and Low Loading
A more sustainable and efficient protocol for the photocatalytic α-amino arylation promoted by fac-Ir(ppy)3 was developed. Three noteworthy results were achieved: i) the replacement of toxic medium DMA with the greener solvents NBP and NHP, and the concurrent improvement of the process efficiency by lowering both the amine and the base amount; ii) the development of a recycling protocol for both the sustainable solvent NHP and the commercially available costly photocatalyst fac-Ir(ppy)3, achieving environmental and economic benefits. This approach to the photocatalyst recovery avoids very demanding catalyst structural modifications; iii) the protocol in green solvents proved to be scalable up to 10 mmol of limiting reagent, maintaining excellent performance also lowering the photocatalyst loading down to 0.05 mol%. This is the first example of photocatalytic α-arylation of amines promoted by such a low amount of catalyst. Lastly, the versatility of this approach was demonstrated by extending the use of the green solvent NBP to another photoredox process
Chemodivergent Photocatalytic Synthesis of Dihydrofurans and β,γ-Unsaturated Ketones
A synthetic procedure, catalysed by Ir(ppy)3 under visible-light irradiation, for the chemodivergent synthesis of 2,3-dihydrofurans (3) or β,γ-unsaturated ketones (7) starting from α-halo ketones (1) and alkenes (2) has been developed. The mild reaction conditions and the redox-neutral nature of the process make it particularly sustainable avoiding the use of both sacrificial reactants and stoichiometric strong oxidants. Careful experimental investigations, supported by DFT calculations, allowed to disclose in details a possible mechanistic pathway and to direct the synthesis chemodivergently either toward 3 or 7, depending not only on the nature of the substrates, but also on the choice of the experimental conditions. (Figure presented.)
Allenamides Playing Domino: A Redox-Neutral Photocatalytic Synthesis of Functionalized 2-Aminofurans
A photoredox catalytic synthesis of functionalized 2-aminofurans is proposed starting from α-halo carbonyl substrates and N-allenamides. The protocol proves to be efficient and sustainable thanks to: i) the use of visible light as green energy source, ii) the redox-neutral nature of the transformation, allowing to avoid additives and strong oxidants, iii) the mild reaction conditions and the functional groups tolerance, iv) the low photocatalyst loading and the absence of excess reagents, v) the one-pot formation of three new bonds in a domino sequence. According to our mechanistic hypothesis, the transformation is configured as a double radical-polar crossover reaction, in which the photocatalyst is excited, oxidized and reduced twice for each molecule of 2-aminofuran produced. The novelty of the designed synthetic approach also lies in the use of N-allenamides as substrates, which, after the addition of the first electrophilic radical, preserve a further reactive π-system, making possible the addition of a second α-keto radical and enabling the installation of a keto functionality at a remote position. The good yields, the broad scope, and the possibility to further synthetically elaborate the obtained furans make this protocol particularly promising for the construction of useful products. (Figure presented.)
Effects of dog-assisted therapies on cognitive mnemonic capabilities in people affected by Alzheimer's disease
Alzheimer’s disease (AD) is the most common cause of dementia in humans and, currently, a valid treatment is lacking. Our goal is to demonstrate the importance and benefits of the relationship with companion animals (considered as co-therapists), intended as a means of facilitating social relations and promoting evident wellbeing in AD patients. The study involved 30 randomly chosen patients with Alzheimer’s disease (group T) and three dogs. The group participated in a total of 24 animal-assisted interventions (AAIs) sessions over a span of 12 weeks, using the Mini-Mental State Examination (MMSE), Wellness and Cognitive Ability Questionnaire (Brief Assessment Cognition or BAC), and Alzheimer’s Disease Assessment Scale (ADAS) as assessment tests. A second group (group C), consisting of 10 people with AD, was enrolled as control group and underwent the same assessment tests but did not benefit from the presence of the dogs. Tests were carried out at time T0 (before starting sessions), T1 (end of sessions), and T2 (two months after last session). People belonging to group T achieved an overall improvement in their perceived state of wellbeing, even on a cognitive and mnemonic plane. However, two months after the end of the sessions, the test results in people suffering from AD decreased towards the baseline (T0). The study shows how such progress can be achieved through activities based on the relationship with an animal, as long as the animal is a steady presence in the life of the patient receiving the intervention. Dogs involved in other dog-assisted therapies have been found suitable also for assisting patients with AD
Wolbachia, doxycycline and macrocyclic lactones: New prospects in the treatment of canine heartworm disease
Abstract Melarsomine dihydrochloride (Immiticide®, Merial) is the only approved adulticidal drug for the treatment of canine heartworm disease (HWD). However, in cases where arsenical therapy is not possible or is contraindicated, a monthly heartworm preventive along with doxycycline for a 4-week period, which targets the bacterial endosymbiont Wolbachia, might be considered. There are published reports on the efficacy of ivermectin and doxycycline in both experimentally and naturally infected dogs, but no data on the use of other macrocyclic lactones (MLs) with a similar treatment regime. Preliminary results of studies in dogs show that a topical formulation of moxidectin, the only ML currently registered as a microfilaricide, is also adulticidal when combined with doxycycline. It is not yet known if the efficacy of these combination therapies is due to pharmacokinetic synergism. A recent study showed that serum levels of doxycycline in dogs treated with the combination protocol were not statistically different compared to dogs treated with doxycycline alone. However, lungs from dogs treated with the combination therapy showed a marked reduction in T regulatory cells, indicating that treatment efficacy may be due to a heightened immune response against the parasite. Further studies are necessary to evaluate the long-term clinical outcome of combination protocols and to establish the most efficient treatment for HWD in dogs
Clinical Effects of the Extract of the Seeds of the Indian Celery-Apium Graveolens-In Horses Affected by Chronic Osteoarthritis.
The extract of the seeds from Indian celery, Apium greaveolens (CSE), tested in experimental
animals (rodents), and in humans aected by chronic osteoarthritic diseases, exhibits anti-inflammatory
eects that can be compared, to some degree, to those of non-steroid anti-inflammatory drugs (NSAID).
In view of a potential use of CSE in the equine species, it was tested on horses aected by chronic
articular pathologies. The trial was performed on 20 horses divided into three dierent groups, orally
treated with 0 (controls), 7.0 or 30 g of CSE BID. Basic orthopedic examinations were conducted, vital
signs were observed, and blood samples collected. Improvement was observed at the highest dosage
tested (30 g of CSE BID), as reflected in the score values of three clinical parameters, (i) amplitude and
(ii) sensitivity to passive flexion and (iii) flexion test. Since the improvement of these parameters can
be correlated with a lower perception of the pain, the present data suggest that the CSE treatment can
have an analgesic eect in horses aected by chronic osteoarthritic diseases
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