Il concetto di storia in Benedetto Croce

No disponibl

Dynamics and protein–solvent interactions of hemoglobin in T and R quaternary conformation

In this work we report the thermal behaviour of the amide I′ band of carbonmonoxy and deoxy hemoglobin in 65% v/v glycerolD8/D2O solutions and in the temperature interval 10–295 K. Following recent suggestions in the literature, we analyze the amide I′ band in terms of two components, one at about 1630 cm−1and the other at about 1650 cm−1, that are assigned to solvent‒exposed and buried α‒helical regions, respectively.For deoxy hemoglobin (in T quaternary structure) both components are narrower with respect to carbonmonoxy hemoglobin (in R quaternary structure), while the peak frequency blue shift observed, upon increasing temperature, for the component at about 1630 cm−1is smaller. The reported data provide evidence of the dependence of hemoglobin dynamic properties upon the protein quaternary structure and suggest a more compact α‒helical structure of hemoglobin in T conformation, with reduced population of low‒frequency modes involving the solvent and protein

Hydrologic vulnerability to climate change of the Mandrone glacier (Adamello-Presanella group, Italian Alps)

In order to assess the annual mass balance of the Mandrone glacier in the Central Alps an energy-balance model was applied, supported by snowpack, meteorological and glaciological observations, together with satellite measurements of snow covered areas and albedo. The Physically based Distributed Snow Land and Ice Model (PDSLIM), a distributed multi-layer model for temperate glaciers, which was previously tested on both basin and point scales, was applied. Verification was performed with a network of ablation stakes over two summer periods. Satellite images processed within the Global Land Ice Measurements from Space (GLIMS) project were used to estimate the ice albedo and to verify the position of the simulated transient snowline on specific dates. The energy balance was estimated for the Mandrone and Presena glaciers in the Central Italian Alps. Their modeled balances (−1439 and −1503 mm w.e. year−1, respectively), estimated over a 15 year period, are in good agreement with those obtained with the glaciological method for the Caresèr glacier, a WGMS (World Glacier Monitoring Service) reference located in the nearby Ortles-Cevedale group. Projections according to the regional climate model COSMO-CLM (standing for COnsortium for Small-scale MOdeling model in CLimate Mode) indicate that the Mandrone glacier might not survive the current century and might be halved in size by 2050

Hydrologic vulnerability to climate change of the Mandrone glacier (Adamello-Presanella group, Italian Alps)

In order to assess the annual mass balance of the Mandrone glacier in the Central Alps an energy- balance model was applied, supported by snowpack, meteorological and glaciological observations, together with satellite measurements of snow covered areas and albedo. The Physically based Distributed Snow Land and Ice Model (PDSLIM), a distributed multi-layer model for temperate glaciers, which was previously tested on both basin and point scales, was applied. Verification was performed with a network of ablation stakes over two summer periods. Satellite images processed within the Global Land Ice Measurements from Space (GLIMS) project were used to estimate the ice albedo and to verify the position of the simulated transient snowline on specific dates. The energy balance was estimated for the Mandrone and Presena glaciers in the Central Italian Alps. Their modeled balances (-1439 and -1503 mm w.e. yr-1, respectively), estimated over a fifteen year period, are in good agreement with those obtained with the glaciological method for the Caresèr glacier, a WGMS (World Glacier Monitoring Service) reference located in the nearby Ortles- Cevedale group. Projections according to the regional climate model COSMO-CLM (standing for COnsortium for Small-scale MOdeling model in CLimate Mode) indicate that the Mandrone glacier might not survive the current century and might be halved in size by 2050

Dynamics of nanoparticles in a supercooled liquid

The dynamic properties of nanoparticles suspended in a supercooled glass forming liquid are studied by x-ray photon correlation spectroscopy. While at high temperatures the particles undergo Brownian motion the measurements closer to the glass transition indicate hyperdiffusive behavior. In this state the dynamics is independent of the local structural arrangement of nanoparticles, suggesting a cooperative behavior governed by the near-vitreous solvent

Intrapancreatic accessory spleen false positive to 68Ga-Dotatoc: case report and literature review

Background: Intrapancreatic accessory spleen (IPAS) is an uncommon finding of pancreatic mass. Differential diagnosis with pancreatic tumor, especially with non-functional neuroendocrine tumor (NF-NET), may be very hard and sometimes it entails unnecessary surgery. A combination of CT scan, MRI, and nuclear medicine can confirm the diagnosis of IPAS. 68-Ga-Dotatoc PET/CT is the gold standard in NET diagnosis and it can allow to distinguish between IPAS and NET. Case presentation: A 69-year-old man was admitted to our hospital for an incidental nodule in the tail of the pancreas with focal uptake of 68-Ga-dotatate at PET/CT. NET was suspected and open distal splenopancreatectomy was performed. Pathologic examination revealed an IPAS. Conclusion: This is the second IPAS case in which a positive 68Ga-Dotatoc uptake led to a false diagnosis of pancreatic NET. Here is a proposal of a literature review

The “Protein Dynamical Transition” Does Not Require the Protein Polypeptide Chain

We give experimental evidence that the main features of protein dynamics revealed by neutron scattering, i.e., the “protein dynamical transition” and the “boson peak”, do not need the protein polypeptide chain. We show that a rapid increase of hydrogen atoms fluctuations at about 220 K, analogous to the one observed in hydrated myoglobin powders, is also observed in a hydrated amino acids mixture with the chemical composition of myoglobin but lacking the polypeptide chain; in agreement with the protein behavior, the transition is abolished in the dry mixture. Further, an excess of low-frequency vibrational modes around 3 meV, typically observed in protein powders, is also observed in our mixture. Our results confirm that the dynamical transition is a water-driven onset and indicate that it mainly involves the amino acid side chains. Taking together the present data and recent results on the dynamics of a protein in denatured conformation and on the activity of dehydrated proteins, it can be concluded that the “protein dynamical transition” is neither a necessary nor a sufficient condition for active protein conformation and function

Computational prediction and molecular confirmation of Helitron transposons in the maize genome

Background: Helitrons represent a new class of transposable elements recently uncovered in plants and animals. One remarkable feature of Helitrons is their ability to capture gene sequences, which makes them of considerable potential evolutionary importance. However, because Helitrons lack the typical structural features of other DNA transposable elements, identifying them is a challenge. Currently, most researchers identify Helitrons manually by comparing sequences. With the maize whole genome sequencing project underway, an automated computational Helitron searching tool is needed. The characterization of Helitron activities in maize needs to be addressed in order to better understand the impact of Helitrons on the organization of the genome. Results: We developed and implemented a heuristic searching algorithm in PERL for identifying Helitrons. Our HelitronFinder program will (i) take FASTA-formatted DNA sequences as input and identify the hairpin looping patterns, and (ii) exploit the consensus 5′ and 3′ end sequences of known Helitrons to identify putative ends. We randomly selected five predicted Helitrons from the program\u27s high quality output for molecular verification. Four out of the five predicted Helitrons were confirmed by PCR assays and DNA sequencing in different maize inbred lines. The HelitronFinder program identified two head-to-head dissimilar Helitrons in a maize BAC sequence. Conclusion: We have identified 140 new Helitron candidates in maize with our computational tool HelitronFinder by searching maize DNA sequences currently available in GenBank. Four out of five candidates were confirmed to be real by empirical methods, thus validating the predictions of HelitronFinder. Additional points to emerge from our study are that Helitrons do not always insert at an AT dinucleotide in the host sequences, that they can insert immediately adjacent to an existing Helitron, and that their movement may cause changes in the flanking region, such as deletions

Changing the Ties That Bind? The Emerging Roles and Identities of General Practitioners and Managers in the New Clinical Commissioning Groups in the English NHS

The English National Health Service (NHS) is undergoing significant reorganization following the 2012 Health and Social Care Act. Key to these changes is the shift of responsibility for commissioning services from Primary Care Trusts (PCTs) to general practitioners (GPs) working together in Clinical Commissioning Groups (CCGs). This article is based on an empirical study that examined the development of emerging CCGs in eight case studies across England between September 2011 and June 2012. The findings are based on interviews with GPs and managers, observations of meetings, and reading of related documents. Scott’s notion that institutions are constituted by three pillars—the regulative, normative, and cognitive–cultural—is explored here. This approach helps to understand the changing roles and identities of doctors and managers implicated by the present reforms. This article notes the far reaching changes in the regulative pillar and questions how these changes will affect the normative and cultural–cognitive pillars

Leukotrienes increase blood-brain barrier permeability following intraparenchymal injections in rats

To examine whether leukotrienes could increase blood–brain barrier permeability, rats were anesthetized and injected intravenously with Evans blue. Ten microliters of vehicle, of leukotrienes B 4 , C 4 , or E 4 , or of arachidonic acid was injected over 1 hour directly into the brain parenchyma. The percentage of the total surface area of Evans blue extravasation in a coronal section of brain centered on the injection site was then determined as an estimate of blood–brain barrier permeability. Leukotrienes B 4 , C 4 , and E 4 , and arachidonic acid all increased blood–brain barrier permeability, but this effect was lost when the total dose was reduced to 20 ng. Increased blood–brain barrier permeability induced by arachidonic acid could be prevented by pretreatment with the lipoxygenase inhibitor BW755C, but not with indomethacin. Leukotrienes may play a role in the development of increased blood–brain barrier permeability after cerebral injury.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50311/1/410180313_ftp.pd