Forme della certezza. Genesi e implicazioni del Fürwahrhalten in Kant

Fürwahrhalten, or “holding-to-be-true”, is one of the most controversial concepts in Kant’s epistemology. Rarely mentioned in Kant’s edited works – where it is often used to describe moral faith – Fürwahrhalten has attracted the interest of Kant scholars only in recent years. The essay aims to shed light on some of the main issues that the notion of holding-to-be-true still rises, especially those concerning its origin and its theoretical function in the critical system. The book retraces the stages of Kant’s reflection on this theme, starting from the precritical discussion with the main representatives of the German Enlightenment (Wolff, Knutzen, Baumgarten, Meier, and Crusius) to the definitive formulation of Fürwahrhalten after the publication of the Critique of Pure Reason. The analysis of Kant’s logical corpus has shown that, far from being a marginal concept of critical epistemology, Fürwahrhalten is the core of a systematic theory of certainty, that Kant develops in accordance with his doctrine of modality. This theory represents the arrival point of a long and troubled reflection, that led Kant to deeply rethink most of the traditional themes of eighteenth-century logic

Plasticizer design strategies enabling advanced applications of cellulose acetate

Plasticized cellulose acetate (CA) is one of the most applied bio-based polymers due to its structural properties and easy processing. Plasticizers are added to CA to increase workability, prevent degradation under processing conditions and ensure thermo-mechanical properties suitable for the intended final application. Moreover, inexpensive and non-toxic solvents enable its processing into fibers, films, and solid blocks. However, when incorporated in the polymer matrix, plasticizers are prone to migration. CA products can suffer embrittlement, cracking, warping, or discoloration during their life cycle, affecting the material’s integrity and durability. The design of new plasticizers compatible with the polymer at high concentrations, tailored to be effective in lowering the glass transition temperature, and with a low tendency to migration could considerably reduce material degradation over time. This review offers a perspective on the current plasticizers and comprehensively depicts the plasticization mechanisms in CA for internal and external plasticization. Understanding the plasticization mechanisms paves the way to identify a rationale for designing new plasticizers for this polymer

A comparison of melatonin and α-lipoic acid in the induction of antioxidant defences in L6 rat skeletal muscle cells.

Aging is characterized by a progressive deterioration in physiological functions and metabolic processes. The loss of cells during aging in vital tissues and organs is related to several factors including oxidative stress and inflammation. Skeletal muscle degeneration is common in elderly people; in fact, this tissue is particularly vulnerable to oxidative stress since it requires large amounts of oxygen, and thus, oxidative damage is abundant and accumulates with increasing age. Melatonin (N-acetyl-5-methoxytryptamine) is a highly efficient scavenger of reactive oxygen species and it also exhibits beneficial anti-inflammatory and anti-aging effects. This study investigated the susceptibility of rat L6 skeletal muscle cells to an induced oxidative stress following their exposure to hydrogen peroxide (50 μM) and evaluating the potential protective effects of pre-treatment with melatonin (10 nM) compared to the known beneficial effect of alpha-lipoic acid (300 μM). Hydrogen peroxide-induced obvious oxidative stress; it increased the expression of tumour necrosis factor-alpha and in turn promoted nuclear factor kappa-B and overrode the endogenous defence mechanisms. Conversely, pre-treatment of the hydrogen peroxide-exposed cells to melatonin or alpha-lipoic acid increased endogenous antioxidant enzymes, including superoxide dismutase-2 and heme oxygenase-1; moreover, they ameliorated significantly oxidative stress damage and partially reduced alterations in the muscle cells, which are typical of aging. In conclusion, melatonin was equally effective as alpha-lipoic acid; it exhibited marked antioxidant and anti-aging effects at the level of skeletal muscle in vitro even when it was given in a much lower dose than alpha-lipoic acid

Propuestas didácticas y recursos utilizados en la enseñanza de la lectura y la escritura en las escuelas primarias

Desde siempre ha interesado el tema de la enseñanza y el aprendizaje de la lengua escrita. Numerosas investigaciones realizadas en el área informan sobre la preocupante situación en cuanto a los resultados que se observan de los procesos de lectura y escritura

FDG imaging with long-axial field-of-view PET/CT in patients with high blood glucose-a matched pair analysis.

PURPOSE High blood glucose (hBG) in patients undergoing [18F]FDG PET/CT scans often results in rescheduling the examination, which may lead to clinical delay for the patient and decrease productivity for the department. The aim of this study was to evaluate whether long-axial field-of-view (LAFOV) PET/CT can minimize the effect of altered bio-distribution in hBG patients and is able to provide diagnostic image quality in hBG situations. MATERIALS AND METHODS Oncologic patients with elevated blood glucose (≥ 8.0 mmol/l) and normal blood glucose ( 11 mmol/l). Tracer uptake in the liver, muscle, and tumor was evaluated. Furthermore, image quality was compared between long acquisitions (ultra-high sensitivity mode, 360 s) on a LAFOV PET/CT and routine acquisitions equivalent to a short-axial field-of-view scanner (simulated (sSAFOV), obtained with high sensitivity mode, 120 s). Tumor-to-background ratio (TBR) and contrast-to-noise ratio (CNR) were used as the main image quality criteria. RESULTS Thirty-one hBG patients met the inclusion criteria and were matched with 31 nBG patients. Overall, liver uptake was significantly higher in hBG patients (SUVmean, 3.07 ± 0.41 vs. 2.37 ± 0.33; p = 0.03), and brain uptake was significantly lower (SUVmax, 7.58 ± 0.74 vs. 13.38 ± 3.94; p  11 mmol/l) patients examined with LAFOV PET/CT showed no statistical significant difference in CNR (19.84 ± 8.40 vs. 17.79 ± 9.3, p = 0.08). CONCLUSION While elevated blood glucose (> 11 mmol) negatively affected TBR and CNR in our cohort, the images from a LAFOV PET-scanner had comparable CNR to PET-images acquired from nBG patients using sSAFOV PET/CT. Therefore, we argue that oncologic patients with increased blood sugar levels might be imaged safely with LAFOV PET/CT when rescheduling is not feasible

Thermal Conductivity Enhancement of Al2O3 Nanofluid in Ethylene Glycol and Water Mixture

AbstractThe ability of nanofluids that exhibits enhanced thermal performance is acknowledged by researchers through studies since decades ago. However, the observation of thermal properties for nanofluids in water and ethylene glycol based is not fully explored yet. Hence, this paper presents the thermal conductivity of water and ethylene glycol (EG) based Al2O3 nanofluid. The 13 nm sized Al2O3 nanoparticles were dispersed into three different volume ratio of water: EG such as 40:60, 50:50 and 60:40 using a two-step method. The measurement of thermal conductivity was performed using KD2 Pro Thermal Properties Analyzer at working temperatures of 30 to 70 ̊C for volume concentration of 0.5 to 2.0%. The results indicate that the thermal conductivity increases with the increase of nanofluid concentration and temperature. While the percentage of ethylene glycol increase, the range of thermal conductivity decreases due to ethylene glycol properties. The measurement data of the nanofluids give maximum enhancement of thermal conductivity at condition 2.0% volume concentration, temperature of 70 ̊C and for all base fluid

Sirtuin 6 localization at cortical brain level of young diabetic mice

The metabolic syndrome, characterized by visceral obesity, dyslipidaemia, hyperglycaemia and hypertension, has become one of the major public-health challenges worldwide and it is strictly associated with the development of type II diabetes and neurodegenerative diseases (Alberti et al. 2005; Panza et al. 2010). Increased metabolic flux to the brain during overnutrition can orchestrate stress response, blood-brain barrier alteration, microglial cells activation and neuroinflammation (Nerurkar et al., 2011). The protein sirtuin family is a class of nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase that act on a variety of targets and so play a key role in central physiological regulation (Sebastian et al., 2012; Wang et al., 2012). To assess the physiopathological significance of sirtuin6 (SIRT6) at brain cortical level, we analysed its specific expression and subcellular localization in young db/db mice, animal model of type II diabetes mellitus, and respective control lean mice. In particular, we analysed the cytoarchitecture of the brain cortex, evaluated SIRT6 expression and its localization by immunohistochemistry comparing young db/db mice to lean control mice, distinguishing among the six cortical layers and between motor and somatosensory cortex. We observed that SIRT6 is mainly localized in the nucleus of both lean and db/db mice. Diabetic mice showed few SIRT6 positive cells respect to lean control mice in all cortical layers without significant differences between motor and somatosensory cortex. No morphological alteration have been find. In conclusion, our findings contribute to further understand SIRT6 protein expression in the early steps of type II diabetes mellitus and suggest its implication in the pathogenic processes of diabetes mellitus and diabetes–induced neurodegeneration

Postextractive alveolar ridge preservation using L-PRF: clinical and histological evaluation

Leukocyte- and platelet-rich fibrin (L-PRF) is an autologous platelet concentrate rich in growth factors and plasma proteins, obtained by centrifugation of patient whole blood, and widely used in oral surgery. This report describes a case of alveolar ridge preservation with L-PRF membranes. Postextractive alveolar healing was then assessed through a histologic and histomorphometric analysis. A patient requiring tooth extraction and subsequent implant rehabilitation was treated with simple extraction and socket filling with L-PRF membranes. Implant placement was performed at 3 months, and a bone biopsy was obtained for histomorphometric analysis. Histological examination of the grafted sites showed that the use of L-PRF could achieve good results in terms of bone dimension and quality and soft tissue healing. The results of this study support the use of L-PRF membranes to preserve hard and soft tissues after tooth extraction

Sirtuin 6 localization at cortical brain level of young diabetic mice

The metabolic syndrome, characterized by visceral obesity, dyslipidaemia, hyperglycaemia and hypertension, has become one of the major public-health challenges worldwide and it is strictly associated with the development of type II diabetes and neurodegenerative diseases (Alberti et al. 2005; Panza et al. 2010). Increased metabolic flux to the brain during overnutrition can orchestrate stress response, blood-brain barrier alteration, microglial cells activation and neuroinflammation (Nerurkar et al., 2011). The protein sirtuin family is a class of nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase that act on a variety of targets and so play a key role in central physiological regulation (Sebastian et al., 2012; Wang et al., 2012). To assess the physiopathological significance of sirtuin6 (SIRT6) at brain cortical level, we analysed its specific expression and subcellular localization in young db/db mice, animal model of type II diabetes mellitus, and respective control lean mice. In particular, we analysed the cytoarchitecture of the brain cortex, evaluated SIRT6 expression and its localization by immunohistochemistry comparing young db/db mice to lean control mice, distinguishing among the six cortical layers and between motor and somatosensory cortex. We observed that SIRT6 is mainly localized in the nucleus of both lean and db/db mice. Diabetic mice showed few SIRT6 positive cells respect to lean control mice in all cortical layers without significant differences between motor and somatosensory cortex. No morphological alteration have been find. In conclusion, our findings contribute to further understand SIRT6 protein expression in the early steps of type II diabetes mellitus and suggest its implication in the pathogenic processes of diabetes mellitus and diabetes–induced neurodegeneration