245 research outputs found
Sol–Gel Method Applied to Crystalline Materials
Sol–gel chemistry is a versatile synthesis used to produce modern materials at nearroom temperature. Glasses, ceramics, composites, and new hybrid materials that are not
easy to obtain using other methods have been, instead, obtained in the last three decades
and nowadays are widely used. Changing the chemical composition, many parameters
of the sol-gel process can be adapted to control the properties and the microstructure of
the obtained materials. Sol-gel technology is a multidisciplinary science which allows the
expansion of materials for many applications. In this Special Issue, special attention is paid
to the properties of materials obtained by using sol–gel methods and to their potential
applications in environmental science and materials science as in catalysis, optics, electronics, energy, biosensors, medicine, and so on
Opening the black box of search & recombination: the cognitive styles of individual creativity
A general equilibrium theory of occupational choice under optimistic beliefs about entrepreneurial ability
This paper studies the impact of optimism on occupational choice using a general equilibrium framework. The model shows that optimism has four main qualitative e ects: it leads to a misallocation of talent, drives up input prices, raises the number of entrepreneurs, and makes entrepreneurs worse o_. We calibrate the model to match U.S. manufacturing data. This allows us to make quantitative predictions regarding the impact of optimism on occupational choice, input prices, the returns to entrepreneurship, and output. The calibration shows that optimism can explain the empirical puzzle of the low mean returns to entrepreneurship compared to average wages.info:eu-repo/semantics/publishedVersio
Embryonic Stem Cells as a Model System to Elucidate Early Events in Cardiac Specification and Determination
Exploring the relationship between types of family involvement and collaborative innovation in design-intensive firms:insights from two leading players in the furniture industry
Innovation in family firms has attracted considerable interest from scholars and practitioners in recent years. However, further theoretical and empirical research is needed to illuminate the intricate relationship between family involvement and innovation. This article studies the effect of different types of family involvement on the management of collaborative innovation. Based on empirical evidence from two leading Italian design-intensive firms in the furniture industry (B&B Italia and Cassina), this study illuminates how family involvement in control and management influences the way design-intensive firms collaborate with external designers to innovate their products. We use two indicators, design renewal and design identity, to capture differences in collaboration approaches through which design-intensive family firms involve external designers. Thus, our findings contribute to understanding how collaborative innovation is managed in family firms. This article also provides family firm owners and managers with insights on the forces that influence the collaborative innovation processes in design-intensive firms
Parkinson’s disease patient-specific neuronal networks carrying the LRRK2 G2019S mutation unveil early functional alterations that predate neurodegeneration
A deeper understanding of early disease mechanisms occurring in Parkinson's disease (PD) is needed to reveal restorative targets. Here we report that human induced pluripotent stem cell (iPSC)-derived dopaminergic neurons (DAn) obtained from healthy individuals or patients harboring LRRK2 PD-causing mutation can create highly complex networks with evident signs of functional maturation over time. Compared to control neuronal networks, LRRK2 PD patients' networks displayed an elevated bursting behavior, in the absence of neurodegeneration. By combining functional calcium imaging, biophysical modeling, and DAn-lineage tracing, we found a decrease in DAn neurite density that triggered overall functional alterations in PD neuronal networks. Our data implicate early dysfunction as a prime focus that may contribute to the initiation of downstream degenerative pathways preceding DAn loss in PD, highlighting a potential window of opportunity for pre-symptomatic assessment of chronic degenerative diseases
Are postnatal traumatic events an underestimated cause of porencephalic lesions in dogs and cats?
IntroductionPorencephaly is defined as a fluid-filled cavity of variable size in the brain cortex. It is regarded as a congenital condition and is typically considered a developmental or an encephaloclastic defect. Our hypothesis is that postnatal traumatic events in the first few months of life may represent a cause of canine and feline porencephaly that is more common than generally suspected. The aims of this study were to retrospectively investigate porencephaly in a large population of dogs and cats, detect MRI features that might be useful to differentiate postnatal acquired traumatic forms from congenital/perinatal porencephaly, and define the prevalence of seizure activity in porencephalic patients.Materials and methodsThis is a double-center, descriptive, retrospective case series. Databases were searched for cases within a 17-year time span that involve dogs and cats with an MRI-based diagnosis of cerebral cavitary lesions. Animals were included if a complete signalment and an exhaustive MRI of the brain were available. Besides the porencephalic lesions, MRIs of the head were reviewed to detect concomitant musculoskeletal abnormalities.ResultsThirty-two cases involving nine cats and twenty-three dogs were selected. Of all the cases, 21.9% were aged six years or older at the time of diagnosis. All patients in which the neuroanatomical localization was available showed clinical signs of a prosencephalic disorder. Epileptic seizures were observed in 71.8% of cases. A single porencephalic cavity was found in 78.1% of cases. The most affected cerebral lobe was the parietal lobe (n = 20). The defects involved both the grey and white matter in 78.1% of cases. Twenty cases showed concomitant musculoskeletal abnormalities overlying the porencephalic cavities. Fourteen of twenty cases showed evidence of fractures, of which thirteen showed depression of the calvarium and twelve masticatory muscle abnormalities. Of these, seven of fourteen had a history consistent with a head trauma in the first period of life.ConclusionThe recognition of skull fractures and muscular abnormalities closely associated with the porencephalic cavity may support a diagnosis of a postnatal traumatic origin of porencephaly. Therefore, this study highlights the importance of evaluating musculoskeletal structures in the MRIs of the heads of porencephalic cases
Invasive meningococcal disease in three siblings with hereditary deficiency of the 8th component of complement: Evidence for the importance of an early diagnosis
Deficiency of the eighth component of complement (C8) is a very rare primary immunodeficiency, associated with invasive, recurrent infections mainly caused by Neisseria species. We report functional and immunochemical C8 deficiency diagnosed in three Albanian siblings who presented with severe meningococcal infections at the age of 15 years, 4 years and 17 months, respectively. The youngest suffered serious complications (necrosis of fingers and toes requiring amputation).
METHODS:
Functional activity of the classical, alternative and mannose-binding lectin complement pathways was measured in serum from the 3 siblings and their parents (37-year-old woman and 42-year-old man). Forty healthy subjects (20 males and 20 females aged 4-38 years) served as normal controls. Serum complement factors were measured by haemolytic assays and immunoblotting. Sequence DNA analysis of the C8B gene was performed.
RESULTS:
Analyses of the three complement pathways revealed no haemolytic activity and also absence of C8beta in serum samples from all three siblings. The genetic analysis showed that the three siblings were homozygous for the p.Arg428* mutation in the C8B gene on chromosome 1p32 (MIM 120960). The parents were heterozygous for the mutation and presented normal complement activities. A 2-year follow-up revealed no further infective episodes in the siblings after antibiotic prophylaxis and meningococcal vaccination.
CONCLUSIONS:
Complement deficiencies are rare and their occurrence is often underestimated. In presence of invasive meningococcal infection, we highlight the importance of complement screening in patients and their relatives in order to discover any genetic defects which would render necessary prophylaxis to prevent recurrent infections and severe complications
PITX2 gain-of-function mutation associated with atrial fibrillation alters mitochondrial activity in human iPSC atrial-like cardiomyocytes
Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide; however, the underlying causes of AF initiation are still poorly understood, particularly because currently available models do not allow in distinguishing the initial causes from maladaptive remodeling that induces and perpetuates AF. Lately, the genetic background has been proven to be important in the AF onset. iPSC-derived cardiomyocytes, being patient- and mutation-specific, may help solve this diatribe by showing the initial cell-autonomous changes underlying the development of the disease. Transcription factor paired-like homeodomain 2 (PITX2) has been identified as a key regulator of atrial development/differentiation, and the PITX2 genomic locus has the highest association with paroxysmal AF. PITX2 influences mitochondrial activity, and alterations in either its expression or function have been widely associated with AF. In this work, we investigate the activity of mitochondria in iPSC-derived atrial cardiomyocytes (aCMs) obtained from a young patient (24 years old) with paroxysmal AF, carrying a gain-of-function mutation in PITX2 (rs138163892) and from its isogenic control (CTRL) in which the heterozygous point mutation has been reverted to WT. PITX2 aCMs show a higher mitochondrial content, increased mitochondrial activity, and superoxide production under basal conditions when compared to CTRL aCMs. However, increasing mitochondrial workload by FCCP or β-adrenergic stimulation allows us to unmask mitochondrial defects in PITX2 aCMs, which are incapable of responding efficiently to the higher energy demand, determining ATP deficiency
Fibroblast growth factor/fibroblast growth factor receptor system in angiogenesis.
Fibroblast growth factors (FGFs) are a family of heparin-binding growth factors. FGFs exert their pro-angiogenic activity by interacting
with various endothelial cell surface receptors, including tyrosine kinase receptors, heparan-sulfate proteoglycans, and integrins. Their
activity is modulated by a variety of free and extracellular matrix-associated molecules. Also, the cross-talk among FGFs, vascular endothelial
growth factors (VEGFs), and inflammatory cytokines/chemokines may play a role in the modulation of blood vessel growth in different
pathological conditions, including cancer. Indeed, several experimental evidences point to a role for FGFs in tumor growth and angiogenesis.
This review will focus on the relevance of the FGF/FGF receptor system in adult angiogenesis and its contribution to tumor vascularization
- …