292 research outputs found
Are You SURE You Want to Waste Policy Chances? Waste Generation, Landfill Diversion and Environmental Policy Effectiveness in the EU15
We empirically test delinking of waste dynamics with regard to economic growth and the effectiveness of environmental and specific waste-related policies, by exploiting a newly constructed, integrated waste-economic-policy dataset based on official data for the EU15 for 1995-2007. We find that absolute delinking for waste generation is far from being achieved in the EU despite fairly stringent and longstanding policy commitment that goes back to the mid 1990s, but which however is biased towards waste management and waste disposal rather than waste prevention. Policy as well as country structural factors seem to impact instead on landfill diversion. Nevertheless, country heterogeneity matters: SURE based analyses show that EU average figures often hide high variance. Their results provide food for thought for a future most comprehensive EU waste policy strategy, which is now aimed mainly at landfill diversion, within a framework strongly oriented to allowing countries to decide about the implementation of EU directives.Waste Generation, Landfill Diversion, SUR, EU Waste Policy, Environmental Policy, Delinking
rheology of wood flour filled poly lactic acid
Abstract This work investigates the rheological properties of wood flour filled poly(lactic acid) at typical processing temperatures, i.e. 155°C, 165°C and 175°C, using a parallel plate rheometer run in oscillatory mode. Materials with three different filler loading levels (10, 20 and 30% wt.) are characterized together with the neat matrix. Considering the complex viscosity curves, it is found that a single master curve can be obtained, which allows to predict the viscosity of the material at any filler loading level and any temperature that are included in the interval tested
Rheology of Wood Polymer Composites
Wood plastic composite (WPC) is a material composed of a thermoplastic matrix filled with wood fibers at different concentrations. This material is widely used for decking and automotive applications. With respect to wood it requires less maintenance, shows better durability in wet environment and can be obtained from recycled materials. With respects to plastics the main advantage is its lower cost.
The aim of this thesis has been to investigate the mechanical and rheological properties of PP based Wood Polymer Composites.
The mechanical characterization has shown that wood fibers make the composite stiffer without lowering strength values too much, while thermal properties have confirmed that the processing window for this material is rather narrow, being limited upwards by wood fiber degradation and downwards by the melting temperature, which is around 165°C.
Commercial PP-based WPCs filled with different filler concentration have been investigated with an off â line rheometer in oscillation mode at 170°C. Complex viscosity increases with the percentage of fibers. All materials show a shear-thinning behaviour with similar slopes of the flow curves and neat PP also displays a Newtonian plateau at low shear rates. The test temperature is imposed by the requirement of performing the test within the linear viscoelasticity region, but the data that are measured are not directly useful for processing, as a convenient processing temperature should be around 195°C.
In order to obtain the WPC viscosity at such temperatures, a model that uses the WPC viscosity measured at 170°C at various wood quantities and of neat PP viscosity measured at various temperatures is proposed. The main hypothesis of this model is that the effects of temperature and filler content on the composite viscosity are disjoint. These measurements permit to create shift factors that allow to estimate the WPC viscosity on the basis of neat PP viscosity, temperature and fibers content.
In order to validate the model, flow curve of 30%wt. and 70%wt. WPC at 195°C have been measured with an instrumented extruder slit die that allows the determination of the flow characteristics of the material in a condition that is very similar to the actual processing conditions. The slit die, connected with a single screw extruder, has a channel that is 50 mm wide and 105 mm long. Three heights are used for the Mooney procedure and three pressure transducers are flush mounted along the slit to eliminate the need for the Bagley correction.
The results show that the viscosity curve for the 30% wt. WPC validates the model presented with a reasonably good agreement. Since the agreement for the 70% wt. is less justified and such a material displays a marked yield stress, we can conclude that it is the yield stress that is probably the single issue that makes the present model questionable.
In this regard, a future work that we propose is to modify the model by selecting a Carreau-Yasuda model with an yield stress to account for the increase in the viscosity at low shear rate
Repurposed Biguanide Drugs in Glioblastoma Exert Antiproliferative Effects via the Inhibition of Intracellular Chloride Channel 1 Activity
The lack of in-depth knowledge about the molecular determinants of glioblastoma (GBM) occurrence and progression, combined with few effective and BBB crossing-targeted compounds represents a major challenge for the discovery of novel and efficacious drugs for GBM. Among relevant molecular factors controlling the aggressive behavior of GBM, chloride intracellular channel 1 (CLIC1) represents an emerging prognostic and predictive biomarker, as well as a promising therapeutic target. CLIC1 is a metamorphic protein, co-existing as both soluble cytoplasmic and membrane-associated conformers, with the latter acting as chloride selective ion channel. CLIC1 is involved in several physiological cell functions and its abnormal expression triggers tumor development, favoring tumor cell proliferation, invasion, and metastasis. CLIC1 overexpression is associated with aggressive features of various human solid tumors, including GBM, in which its expression level is correlated with poor prognosis. Moreover, increasing evidence shows that modification of microglia ion channel activity, and CLIC1 in particular, contributes to the development of different neuropathological states and brain tumors. Intriguingly, CLIC1 is constitutively active within cancer stem cells (CSCs), while it seems less relevant for the survival of non-CSC GBM subpopulations and for normal cells. CSCs represent GBM development and progression driving force, being endowed with stem cell-like properties (self-renewal and differentiation), ability to survive therapies, to expand and differentiate, causing tumor recurrence. Downregulation of CLIC1 results in drastic inhibition of GBM CSC proliferation in vitro and in vivo, making the control of the activity this of channel a possible innovative pharmacological target. Recently, drugs belonging to the biguanide class (including metformin) were reported to selectively inhibit CLIC1 activity in CSCs, impairing their viability and invasiveness, but sparing normal stem cells, thus representing potential novel antitumor drugs with a safe toxicological profile. On these premises, we review the most recent insights into the biological role of CLIC1 as a potential selective pharmacological target in GBM. Moreover, we examine old and new drugs able to functionally target CLIC1 activity, discussing the challenges and potential development of CLIC1-targeted therapies
Centrin 2: a novel marker of mature and neoplastic human astrocytes
As microtubule organizing centers, centrosomes play a pivotal role in cell division as well as in neurodevelopment and neuronal maturation. Among centrosomal proteins, centrin-2 (CETN2) contributes also to DNA repair mechanisms which are fundamental to prevent genomic instability during neural stem cell pool expansion. Nevertheless, the expression profile of CETN2 in human neural stem cells and their progeny is currently unknown.
To address this question, we interrogated a platform of human neuroepithelial stem (NES) cells derived from post-mortem developing brain or established from pluripotent cells, and demonstrated that while CETN2 retains its centrosomal location in proliferating NES cells, its expression pattern changes upon differentiation. In particular, we found that CETN2 is selectively expressed in mature astrocytes with a broad cytoplasmic distribution. We then extended our findings on human autoptic nervous tissue samples. We investigated CETN2 distribution in diverse anatomical areas along the rostro-caudal neuraxis and pointed out a peculiar topography of CETN2-labelled astrocytes in humans which was not appreciable in murine tissues, where CETN2 was mostly confined to ependymal cells. As prototypical condition with glial overproliferation, we also explored CETN2 expression in glioblastoma multiforme, reporting a focal concentration of CETN2 in neoplastic astrocytes.
This study expands CETN2 localization beyond centrosomes and reveals a unique expression pattern which makes it eligible as a novel astrocytic molecular marker, thus opening new roads to glial biology and human neural conditions
Drug-Free Hybrid Nanoarchitecture Modulation of the Metastatic Behavior of Pancreatic Ductal Adenocarcinoma in Alternative in Vivo Models
Metastasis is the key cause of treatment failure in most oncological patients. The spreading of cancer cells to distal
tissues and organs can be associated with the epithelial-to-mesenchymal transition (EMT) that reduces or nullifies the effectiveness
of the actual treatments. In this context, the establishment of effective antimetastatic agents is the final frontier in cancer research.
Noble metal nanomaterials may allow advancements in this regard, but the issue of their persistence precludes their translation to
clinics despite their antimetastatic properties. Here, we demonstrate that non-persistent gold and copper ultrasmall-in-nano
architectures (NAs) conceived by a safe-by-design approach reduce tumor growth and modulate the progression of the metastasis by
altering gene and protein expression of the EMT-related factors in alternative in vivo models of pancreatic ductal adenocarcinoma.
Together with these findings, we also introduce an alternative biomodel for the evaluation of metastasis to mimic the heterogeneity
of the metastatic phenomenon. On a broader basis, our results represent a promising step forward in the development of novel
families of ultrasmall-in-nano antimetastatic agents for the establishment of the next clinical approaches for pancreatic cancer
metastasis
Experimental and Numerical Analysis of a Non-Newtonian Fluids Processing Pump
Abstract Centrifugal pumps are used in many applications in which non-Newtonian fluids are involved: food processing industry, pharmaceutical and oil/gas applications. In addition to pressure and temperature, the viscosity of a non-Newtonian fluid depends on the shear rate and usually is several orders of magnitude higher than water. High values of viscosity cause a derating of pump performance with respect to water. Nowadays, pumping and mixing non-Newtonian fluids is a matter of increasing interest, but there is still lack of a detailed analysis of the fluid-dynamic phenomena occurring within these machines. A specific design process should take into account these effects in order to define the proper pump geometry, able to operate with non-Newtonian fluids with specific characteristics. Only few approaches are available for correcting the pump performance based on the Hydraulic Institute method. In this work, an experimental and numerical campaign is presented for a semiâopen impeller centrifugal pump elaborating non-Newtonian fluids. An on-purpose test bench was built and used to investigate the influence on pump performance of three different non-Newtonian fluids. Each pump performance test was accompanied by the rheological characterization of the fluid, in order to detect modifications of the rheological phenomena and allow a proper Computation Fluid Dynamics (CFD) modeling. The performance of the machine handling both Newtonian and non-Newtonian fluids are highlighted in relation with the internal flow field
Impact of the European Union on access to medicines in low- and middle-income countries: A scoping review
This Scoping Review synthesises evidence of the impacts of European Union (EU) law, regulation, and policy on access to medicines in in non-EU low- and middle-income countries (LMICs), and the mechanisms and nature of those impacts. We searched eight scholarly databases and grey literature published between 1995-2021 in four languages. The EU exerts global influence on pharmaceuticals in LMICs in three ways: explicit agreements between EU-LMICs (ex. accession, trade, and economic agreements); LMICs' reliance on EU internal regulation, standards, or methods (ex. market authorisation); âsoftâ forms of EU influence (ex. research funding, capacity building). This study illustrates that EU policy makers adopt measures with the potential to influence medicines in LMICs despite limited evidence of their positive and/or negative impact(s). The EU's fragmented internal and external actions in fields related to pharmaceuticals reveal the need for principles for global equitable access to medicines to guide EU policy
A human MMTV-like betaretrovirus linked to breast cancer has been present in humans at least since the copper age
The betaretrovirus Mouse Mammary Tumor Virus (MMTV) is the well characterized etiological agent of mammary tumors in mice. In contrast, the etiology of sporadic human breast cancer (BC) is unknown, but accumulating data indicate a possible viral origin also for these malignancies. The presence of MMTVenv-like sequences (MMTVels) in the human salivary glands and saliva supports the latter as possible route of interhuman dissemination. In the absence of the demonstration of a mouse-man transmission of MMTV, we considered the possibility that a cross-species transmission could have occurred in ancient times. Therefore, we investigated MMTVels in the ancient dental calculus, which originates from saliva and is an excellent material for paleovirology. The calculus was collected from 36 ancient human skulls, excluding any possible mouse contamination. MMTV-like sequences were identified in the calculus of 6 individuals dated from the Copper Age to the 17th century. The MMTV-like sequences were compared with known human endogenous betaretroviruses and with animal exogenous betaretroviruses, confirming their exogenous origin and relation to MMTV. These data reveal that a human exogenous betaretrovirus similar to MMTV has existed at least since 4,500 years ago and indirectly support the hypothesis that it could play a role in human breast cancer
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