311 research outputs found
Propagation and stability of optical pulses in a diffractive dispersive non-linear medium
Propagation and stability of light pulses under the combined influence of the optical Kerr effect, dispersion and diffraction are investigated by adopting a variational procedure. In particular, it is found that 'light bullets', i.e. radially symmetric pulses propagating without distortion, are not necessarily unstable under perturbations which do not maintain radial symmetry
Effects of granulocyte-macrophage colony-stimulating factor and cyclic AMP interaction on human neutrophil apoptosis.
The current study was undertaken to evaluate the effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) and cyclic AMP (cAMP) signaling interaction on human neutrophil apoptosis, either occurring spontaneously or induced by Fas antigen activation. Results show that GM-CSF, dibutyryl cAMP (a cAMP analog) and forskolin (an adenylate cyclase activator) are all able to suppress spontaneous neutrophil cell death. Of note however, when GM-CSF is used in combination with cAMP-elevating agents, an additive effect on neutrophil survival is observed with dibutyryl cAMP only, whereas supplementation of cell cultures with GM-CSF and forskolin results in a progressive reduction of antiapoptotic effects exerted by the single compounds. Moreover, although dibutyryl cAMP and forskolin do not affect Fas-triggered apoptotic events, they are still able to modulate the GM-CSF capacity to prolong neutrophil survival following anti-Fas IgM cell challenge, with effects similar to those respectively exerted on spontaneous neutrophil apoptosis. The data indicate that GM-CSF may negatively modulate the cAMP-mediated antiapoptotic pathway in human neutrophils, likely via the inhibition of adenylate cyclase activity. This would prevent an abnormal neutrophil survival as a result of cAMP signaling stimulation, which provides a novel insight into the role of GM-CSF as a physiological regulator of myeloid cell turnover
Qualitative analysis of the capacity to consent to treatment in patients with a chronic neurodegenerative disease. Alzheimer's Disease.
Objective: Informed consent is an essential element in doctor–patient relationship. In particular, obtaining valid informed consent from patients with neurocognitive diseases is a critical issue at present. For this reason, we decided to conduct research on elderly patients with Alzheimer’s disease (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) to assess their capacity to make treatment decisions.
Methods: The experimental group comprised 70 Alzheimer patients who were admitted to the Neurodegenerative Disease Unit of the University of Bari. The control group consisted of 83 elderly patients without neurocognitive disorders who were hospitalized in the Geriatric Unit at the same university. After providing written consent to participate in the research, each subject underwent the following assessments: (a) assessment of comprehension sheet, (b) Neuropsychiatric Inventory (NPI) and Global Functioning Evaluation (GFE), (c) neurological evaluation, (d) neuropsychological assessment with a full battery of tests, (d) The MacArthur Treatment Competence Study (MacArthur Competence Assessment Tool for Treatment (MacCAT-T); understanding, appreciating, reasoning and expressing a choice) and (e) a semi-structured interview administered by the patient’s caregiver.
Results/conclusion: The present survey was designed to analyze possible qualitative and quantitative correlations between cognitive functioning and capacity to consent in relation to different degrees of severity of the neurodegenerative disorder. A large portion of the patients in our experimental sample did not appear to have the capacity to provide a valid consent. The authors present initial results of this study and discuss their possible implications
Alumina-on-alumina total hip replacement for femoral neck fracture in healthy patients
<p>Abstract</p> <p>Background</p> <p>Total hip replacement is considered the best option for treatment of displaced intracapsular fractures of the femoral neck (FFN). The size of the femoral head is an important factor that influences the outcome of a total hip arthroplasty (THA): implants with a 28 mm femoral head are more prone to dislocate than implants with a 32 mm head. Obviously, a large head coupled to a polyethylene inlay can lead to more wear, osteolysis and failure of the implant. Ceramic induces less friction and minimal wear even with larger heads.</p> <p>Methods</p> <p>A total of 35 THAs were performed for displaced intracapsular FFN, using a 32 mm alumina-alumina coupling.</p> <p>Results</p> <p>At a mean follow-up of 80 months, 33 have been clinically and radiologically reviewed. None of the implants needed revision for any reason, none of the cups were considered to have failed, no dislocations nor breakage of the ceramic components were recorded. One anatomic cementless stem was radiologically loose.</p> <p>Conclusions</p> <p>On the basis of our experience, we suggest that ceramic-on-ceramic coupling offers minimal friction and wear even with large heads.</p
KRAS-regulated glutamine metabolism requires UCP2-mediated aspartate transport to support pancreatic cancer growth
The oncogenic KRAS mutation has a critical role in the initiation of human pancreatic ductal adenocarcinoma (PDAC) since it rewires glutamine metabolism to increase reduced nicotinamide adenine dinucleotide phosphate (NADPH) production, balancing cellular redox homeostasis with macromolecular synthesis1,2. Mitochondrial glutamine-derived aspartate must be transported into the cytosol to generate metabolic precursors for NADPH production2. The mitochondrial transporter responsible for this aspartate efflux has remained elusive. Here, we show that mitochondrial uncoupling protein 2 (UCP2) catalyses this transport and promotes tumour growth. UCP2-silenced KRASmut cell lines display decreased glutaminolysis, lower NADPH/NADP+ and glutathione/glutathione disulfide ratios and higher reactive oxygen species levels compared to wild-type counterparts. UCP2 silencing reduces glutaminolysis also in KRASWT PDAC cells but does not affect their redox homeostasis or proliferation rates. In vitro and in vivo, UCP2 silencing strongly suppresses KRASmut PDAC cell growth. Collectively, these results demonstrate that UCP2 plays a vital role in PDAC, since its aspartate transport activity connects the mitochondrial and cytosolic reactions necessary for KRASmut rewired glutamine metabolism2, and thus it should be considered a key metabolic target for the treatment of this refractory tumour
Preliminary analysis of ground-to-flight mechanical tolerances of the Ariel mission telescope
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