Ab initio prediction of magnetically dead layers in freestanding γ\gamma-Ce(111)

It is well known that the surface of nonmagnetic $\alpha$-Ce is magnetically ordered, i.e., $\gamma$-like. One then might conjecture, in agreement with previous theoretical predictions, that the $\gamma$-Ce may also exhibit at its surfaces even more strongly enhanced $\gamma$-like magnetic ordering. Nonetheless, our result shows that the (111)-surfaces of magnetic $\gamma$-Ce are neither spin nor orbitally polarized, i.e., $\alpha$-like. Therefore, we predict, in contrast to the nonmagnetic $\alpha$-phase which tends to produce magnetically ordered $\gamma$-like thin layers at its free surfaces, the magnetic $\gamma$-phase has a tendency to form $\alpha$-like dead layers. This study, which explains the suppressed (promoted) surface magnetic moments of $\gamma$-Ce ($\alpha$-Ce), shows that how nanoscale can reverse physical properties by going from bulk to the surface in isostructural $\alpha$- and $\gamma$-phases of cerium. We predict using our freestanding surface results that a typical unreactive and non-diffusive substrate can dramatically influence the magnetic surface of cerium thin films in contrast to most of the uncorrelated thin films and strongly correlated transition metals. Our result implies that magnetic surface moments of $\alpha$-Ce(111) can be suddenly disappeared by increasing lattice mismatch at the interface of a typical unreactive and non-diffusive substrate with cerium overlayers.Comment: 6 pages, 3 figures, 1 tabl

Shrinkage performance of fly ash alkali-activated cement based binder mortars

Some authors reported that Alkali-activated Cement Based Binder (AACB) mortars can have much higher drying shrinkage than Portland cement based composites. Its worth remember that shrinkage performance is a very important property for reinforced concrete composites just because a high shrinkage performance is associated to cracking tendency that leads to future durability problems. Usually shrinkage is assessed under unrestrained conditions. However, the use of a restrained ellipse ring test is especially interesting for materials that will be used in restrained conditions like repair mortars. This paper provides results on restrained and unrestrained shrinkage performance of fly ash AACB mortars. The restrained shrinkage was assessed with an elliptical ring that provides a faster and more reliable assessment of the cracking potential than circular rings. The results show that the mixtures with lower sodium silicate content are associated to a lower unrestrained shrinkage. Mixtures with lower sodium silicate content showed reduced average crack width under restrained conditions. The results also show that the reduction of sodium silicate content delays the appearance of cracks and is also associated to lower crack width. The use of AACB mortars in restrained conditions requires the use of a reduced sodium silicate content or else the use of fibres to prevent crack appearance.Foundation for Science and Technology (FCT): IF/00706/2014-UM.2.15info:eu-repo/semantics/acceptedVersio

Flow performance of hybrid cement based mortars

This paper reports experimental results of 32 hybrid cement mixes regarding the joint effect of sodium hydroxide concentration, the use of a commercial superplasticizer and a biopolymer on the flow and compressive strength performance. The results show that the use of commercial admixtures led to a slightly increase in the flow of mortars with lower sodium hydroxide concentration. A mixture based on 80% fly ash, 10% calcium hydroxide and 10% waste glass showed the highest compressive strength. A compressive strength decrease was noticed concerning the use of the two admixtures that can due to the fact that those admixtures are not stable on high basic media. The authors would like to acknowledge the financial support of the Foundation for Science and Technology (FCT) in the frame of project IF/00706/2014-UM.2.15info:eu-repo/semantics/publishedVersio

Experimental and numerical investigations on the flexural performance of geopolymers reinforced with short hybrid polymeric fibres

Geopolymers have much higher drying shrinkage than Portland cement based composites Shrinkage performance is an important property for reinforced concrete composites just because a high shrinkage performance is associated to cracking tendency that leads to future durability problems. This paper provides results experimental and numerical investigations of fly ash based geopolymeric mortars reinforced with short hybrid polymeric fibres (SHPF). The results show that SHPF improved the flexural performance, while reducing the compressive strength and flexural stiffness of geopolymeric mortars. The addition of 0.8% SHPF increased about two times the fracture energy and about 50% the tensile strength. The adopted constitutive model well-captured the flexural performance of the tested beams.Foundation for Science and Technologyinfo:eu-repo/semantics/publishedVersio

Short-term compressive strength of fly ash and waste glass alkali-activated cement based binder (AACB) mortars with two biopolymers

The Roadmap to a Resource Efficient Europe aims that by 2020, waste will be managed as a resource. Thus materials that have the ability for the reuse of several types of wastes, such as alkali-activated cement-based binders (AACBs), will merit special attention. Some wastes like fly ash deserve special attention because they are generated in high amounts and have a very low reuse rate. This paper reports experimental results regarding the influence of the mix design of fly ash and waste glass AACB mortars containing two different biopolymers (carrageenan and xanthan) on their short-term mechanical performance. Microstructure and cost analysis are also included. The results show that a mixture of 80% fly ash, 10% waste glass, and 10% calcium hydroxide activated with an alkaline activator has the highest compressive strength. The results also show that the mortars with minor biopolymer carrageenan content are associated with a relevant increase in compressive strength and that the use of 0.1% of carrageenan leads to optimum compressive strength in most mixtures. The use of xanthan shows no beneficial effects on the compressive strength of AACB mortars. Several mixtures with xanthan even show a reduction in the compressive strength.The authors would like to acknowledge the financial support of the Foundation for Science and Technology (FCT) in the frame of project IF/00706/2014-UM.2.15.info:eu-repo/semantics/acceptedVersio

Differential gene-expression of metallothionein 1M and 1G in response to zinc in sertoli TM4 cells

Background: Zinc (Zn) as an important trace element is essential for testicular development and spermatogenesis. Molecular mechanism of Zn action in the reproductive system may be related to metal binding low-molecular weight proteins, metallothioneins (MT). Our objective was to determine the effect of Zn on two important isoforms of MT, MT1M and MT1G genes expression on testicular sertoli cells. Methods: Cultured sertoli TM4 cells were exposed to different concentrations of Zn at different time points. Cellular uptake of Zn was tested using flame atomic absorption spectrometry. The cellular viability and gene expression were assessed by MTT and real-time PCR methods, respectively. Results: The treated cells resulted in higher Zn concentration and cellular viability. The expression of MT1M and MT1G genes in the treated cells were greater than those of the untreated cells (P<0.05). In the high dosage treated group (100 and 500 μM), Zn concentration and expression of MT1M and MT1G genes increased three h after treatment; MT1G gene expression increased more at sixth h. At 18th h of treatment, the expression of both genes especially MT1G, increased dramatically while Zn concentration decreased. Conclusion: Since the increase of MT1G mRNA was coincident with cellular Zn level, it seems that MT1G has a more prominent role than MT1M in the homeostasis of Zn. In addition, Zn at dosage of 50 μM (pharmacologic concentration) may protect cells by increasing the expression of MT genes at longer periods

Comparing Vitamin D Level Between Patients with Psoriasis and Healthy Individuals: A Systematic Review and Meta-Analysis

Background: Psoriasis is nowadays regarded as a systemic inflammatory disorder. Among the topicals, vitamin D derivates are often applied on the skin for their anti-inflammatory and immune-modulatory properties. Vitamin D serum levels in psoriasis (PsO) patients are still debated and an eventual depletion may offer the rational to integrate anti-psoriatic therapies with oral vitamin D. Then, we aimed to perform a systematic review and meta-analysis on the current evidence towards serum vitamin D level in PsO. Methods: We searched in PubMed, Scopus, Web of Sciences, ScienceDirect and Science Information Database (SID) using the terms “Vitamin D” and “Psoriasis” including manuscripts in English, Italian and Persian. Duplications were excluded using EndNote software and records were screened by title, abstract and full-text. Quality assessment of studies was assessed using Newcastle Ottawa Checklist (NOS). Psoriasis odds ratio (OR) and mean serum vitamin D levels were calculated and displayed in Forest-plots. Heterogeneity indexes were evaluated using I2 and Q. Sensitivity analysis and publication biases were also considered. Results: From 3006 records extracted, after removing duplicates and analyzing full texts we finally included 19 manuscripts involving a total of 1387 PsO cases and 6939 controls. PsO patients exhibited a substantial odds ratio (3.07, 95% CI: 1.56-6.04) for lower serum vitamin D levels compared to the control group. Standardized Mean Difference (SMD) of vitamin D in PsO versus controls was −0.92 (−1.33 to −0.51). Conclusion: Psoriatic patients displayed higher risk to have a vitamin D deficiency. Interventional studies to verify the preventive value are mandatory

Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.

A considerable body of research indicates that mammary gland branching morphogenesis is dependent, in part, on the extracellular matrix (ECM), ECM-receptors, such as integrins and other ECM receptors, and ECM-degrading enzymes, including matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). There is some evidence that these ECM cues affect one or more of the following processes: cell survival, polarity, proliferation, differentiation, adhesion, and migration. Both three-dimensional culture models and genetic manipulations of the mouse mammary gland have been used to study the signaling pathways that affect these processes. However, the precise mechanisms of ECM-directed mammary morphogenesis are not well understood. Mammary morphogenesis involves epithelial 'invasion' of adipose tissue, a process akin to invasion by breast cancer cells, although the former is a highly regulated developmental process. How these morphogenic pathways are integrated in the normal gland and how they become dysregulated and subverted in the progression of breast cancer also remain largely unanswered questions

Thermal performance of resource-efficient geopolymeric mortars containing phase change materials

Energy efficiency is not only the most cost effective way to reduce emissions but also a way to improve competitiveness and create employment. This paper reports experimental results on the thermal performance of geopolymeric mortars containing different percentages of phase-change materials-PCMs. These materials have a twofold positive impact concerning eco-efficiency. On one hand, the mortars are based on industrial waste contributing for resource efficiency. And on the other hand, PCM based mortars have the capacity to enhance the thermal performance of the buildings. Five groups of alkali-activated based mortars with different PCM percentages were produced and placed on a panel within a small-scale prototype for thermal performance testing. The results show that the thermal conductivity of the mortars decreased with the increase in the percentage of the PCM. The results also show that the thermal performance of the PCM based mortars allowed for a stronger attenuation of the temperature amplitudes. Both for heating and cooling loads. The authors would like to acknowledge the financial support from the Foundation for Science and Technology (FCT) for the frame of research project with Ref. IF/00706/2014-UM.2.15 as well as C-TAC and ISISE research units.info:eu-repo/semantics/publishedVersio