Single photon detection up to 2 µm in pair of parallel microstrips based on NbRe ultrathin films.

Superconducting microstrip single photon detectors (SMSPDs) are increasingly attracting the interest of the scientific community as a new platform for large area detectors with unprecedented advantaged in terms of fabrication. However, while their operativity at the telecommunication wavelength was achieved, working beyond 1.55 µm is challenging. Here, we experimentally demonstrate single-photon operation of NbRe microstrips at wavelengths of 1.55 and 2 µm. The devices are structured as pairs of parallel microstrips with widths ranging from 1.4 to 2.2 µm and lengths from 5 to 10 µm. This innovative design may assure large sensitive areas, without affecting the kinetic inductance, namely the time performance of the detectors. The results are discussed in the framework of the hot-spot two-temperature model.

Biomimetic approach for an articular cartilage patch: Combination of decellularized cartilage matrix and silk-elastin-like-protein (SELP) hydrogel.

Articular cartilage degradation due to injury, disease and aging is a common clinical issue as current regenerative therapies are unable to fully replicate the complex microenvironment of the native tissue which, being avascular, is featured by very low ability to self-regenerate. The extracellular matrix (ECM), constituting almost 90% of the entire tissue, plays a critical role in its function and resistance to compressive forces. In this context, the current tissue engineering strategies are only partially effective in restoring the biology and function of the native tissue. A main issue in tissue regeneration is treatment failure due to scarce integration of the engineered construct, often following a gradual detachment of the graft. In this scenario, we aimed to create an adhesive patch able to adequately support cartilage regeneration as a promising tool for the treatment of cartilage injuries and diseases. For this, we produced an engineered construct composed of decellularized ECM (dECM) obtained from horse joint cartilage, to support tissue regeneration, coupled with a Silk-Elastin-Like Proteins (SELP) hydrogel, which acts as a biological glue, to guarantee an adequate adherence to the host tissue. Following the production of the two biomaterials we characterized them by assessing: 1) dECM morphological, chemical, and ultrastructural features along with its capability to support chondrocyte proliferation, specific marker expression and ECM synthesis; 2) SELP microarchitecture, cytocompatibility and mechanical properties. Our results demonstrated that both materials hold unique properties suitable to be exploited to produce a tailored microenvironment to support cell growth and differentiation providing a proof of concept concerning the in vitro biological and mechanical efficacy of the construct. The SELP hydrogel displayed a very interesting physical behavior due to its high degree of resistance to mechanical stress, which is generally associated with physiological mechanical load during locomotion. Intriguingly, the shear-thinning behavior of the hydrogel may also make it suitable to be applied and spread over non-homogeneous surfaces, therefore, we hypothesize that the hybrid biomaterial proposed may be a real asset in the treatment of cartilage defects and injuries.

Effect of the substrate on the electrical transport and fluctuation processes in NbRe and NbReN ultrathin films for superconducting electronics applications.

NbRe-based superconducting thin films recently received relevant interest in the field of low-temperature electronics. However, for these materials the electrical conduction mechanisms, in particular in the normal state, still need to be investigated in more detail. Here, NbRe and NbReN films of different thicknesses have been deposited on two different substrates, namely monocrystalline Si and [Formula: see text] buffered Si. The films were characterized by DC electrical transport measurements. Moreover, a connection with the charge carriers fluctuation processes has been made by analyzing the electrical noise generated in the normal state region. Despite the films morphology seems not to be affected by the substrate used, a lower noise level has been found for the ones grown on [Formula: see text], in particular for NbReN. From this study it emerges that both NbRe and NbReN ultrathin films are of very good quality, as far as the low-temperature electrical noise and conduction are concerned, with noise levels competitive with NbN. These results may further support the proposal of using these materials in a nanowire form in the field of superconducting electronics.

Active targeting of cancer cells by CD44 binding peptide-functionalized oil core-based nanocapsules.

Selectivity in tumor targeting is one of the major issues in cancer treatment. Therefore, surface functionalization of drug delivery systems with active moieties, able to selectively target tumors, has become a worldwide-recognized strategy. The CD44 receptor is largely used as a biomarker, being overexpressed in several tumors, and consequently as a target thanks to the identification of the CD44 binding peptide. Here we implemented the CD44 binding peptide logic onto an oil core-polymer multilayer shell, taking into account and optimizing all relevant features of drug delivery systems, such as small size (down to 100 nm), narrow size distribution, drug loading capability, antifouling and biodegradability. Besides promoting active targeting, the oil core-based system enables the delivery of natural and synthetic therapeutic compounds. Biological tests, using curcumin as a bioactive compound and fluorescent tag, demonstrated that CD44 binding peptide-functionalized nanocapsules selectively accumulate and internalize in cancer cells, compared to the control, thanks to ligand-receptor binding.

NbN superconducting nanonetwork fabricated using porous silicon templates and high-resolution electron beam lithography.

Superconducting NbN nanonetworks with a very small number of interconnected nanowires, with diameter of the order of 4 nm, are fabricated combining a bottom-up (use of porous silicon nanotemplates) with a top-down technique (high-resolution electron beam lithography). The method is easy to control and allows the fabrication of devices, on a robust support, with electrical properties close to a one-dimensional superconductor that can be used fruitfully for novel applications.

Vasculogenic potential evaluation of bottom-up, PCL scaffolds guiding early angiogenesis in tissue regeneration.

Vascularization is a key factor in the successful integration of tissue engineered (TE) grafts inside the host body. Biological functions of the newly formed tissue depend, in fact, on a reliable and fast spread of the vascular network inside the scaffold. In this study, we propose a technique for evaluating vascularization in TE constructs assembled by a bottom-up approach. The rational, ordered assembly of building blocks (BBs) into a 3D scaffold can improve vessel penetration, and-unlike most current technologies-is compatible with the insertion of different elements that can be designed independently (e.g. structural units, growth factor depots etc.). Poly(ε-caprolactone) scaffolds composed of orderly and randomly assembled sintered microspheres were used to assess the degree of vascularization in a pilot in vivo study. Scaffolds were implanted in a rat subcutaneous pocket model, and retrieved after 7 days. We introduce three quantitative factors as a measure of vascularization: the total percentage of vascularization, the vessels diameter distribution and the vascular penetration depth. These parameters were derived by image analysis of microcomputed tomographic scans of biological specimens perfused with a radiopaque polymer. The outcome of this study suggests that the rational assembly of BBs helps the onset and organization of a fully functional vascular network.

Nonequilibrium fluctuations as a distinctive feature of weak localization.

Two-dimensional materials, such as graphene, topological insulators, and two-dimensional electron gases, represent a technological playground to develop coherent electronics. In these systems, quantum interference effects, and in particular weak localization, are likely to occur. These coherence effects are usually characterized by well-defined features in dc electrical transport, such as a resistivity increase and negative magnetoresistance below a crossover temperature. Recently, it has been shown that in magnetic and superconducting compounds, undergoing a weak-localization transition, a specific low-frequency 1/f noise occurs. An interpretation in terms of nonequilibrium universal conductance fluctuations has been given. The universality of this unusual electric noise mechanism has been here verified by detailed voltage-spectral density investigations on ultrathin copper films. The reported experimental results validate the proposed theoretical framework, and also provide an alternative methodology to detect weak-localization effects by using electric noise spectroscopy.

Superconducting nanowire quantum interference device based on Nb ultrathin films deposited on self-assembled porous Si templates.

Magnetoresistance oscillations were observed on networks of superconducting ultrathin Nb nanowires presenting evidence of either thermal or quantum activated phase slips. The magnetic transport data, discussed in the framework of different scenarios, reveal that the system behaves coherently in the temperature range where the contribution of the fluctuations is important.

Intraoperative administration of inhaled carbon monoxide reduces delayed graft function in kidney allografts in Swine.

Ischemia/reperfusion injury and delayed graft function (DGF) following organ transplantation adversely affect graft function and survival. A large animal model has not been characterized. We developed a pig kidney allograft model of DGF and evaluated the cytoprotective effects of inhaled carbon monoxide (CO). We demonstrate that donor warm ischemia time is a critical determinant of DGF as evidenced by a transient (4-6 days) increase in serum creatinine and blood urea nitrogen following transplantation before returning to baseline. CO administered to recipients intraoperatively for 1 h restored kidney function more rapidly versus air-treated controls. CO reduced acute tubular necrosis, apoptosis, tissue factor expression and P-selectin expression and enhanced proliferative repair as measured by phosphorylation of retinol binding protein and histone H3. Gene microarray analyses with confirmatory PCR of biopsy specimens showed that CO blocked proinflammatory gene expression of MCP-1 and heat shock proteins. In vitro in pig renal epithelial cells, CO blocks anoxia-reoxygenation-induced cell death while promoting proliferation. This large animal model of DGF can be utilized for testing therapeutic strategies to reduce or prevent DGF in humans. The efficacy of CO on improving graft function posttransplant validates the model and offers a potentially important therapeutic strategy to improve transplant outcomes.

Upper critical magnetic fields in superconductor/ferromagnet hybrids.

We measured parallel upper critical magnetic fields in Nb/PdNi and Nb/CuNi bilayers and Nb/PdNi/Nb and Nb/CuNi/Nb trilayers. In the bilayers case the measurements reveal a dependence of the reduced two-dimensional-three-dimensional crossover temperature, t(cr) = T(cr)/T(c), on the different values of the superconductor (S)/ferromagnet (F) interface transparencies. In the case of the trilayers we observe that the reduced crossover temperature as a function of the ferromagnetic layer thickness, d(F), reaches a value equal to one only when the π-phase occurs in these systems. Also in this case the influence of the interface transparency on the observed results is discussed.

Magnetic field and temperature dependence of the critical vortex velocity in type-II superconducting films.

We study the vortex dynamics in the instability regime induced by high dissipative states well above the critical current in Nb superconducting strips. The magnetic field and temperature behavior of the critical vortex velocity corresponding to the observed dynamic instability is ascribed to intrinsic non-equilibrium phenomena. The Larkin-Ovchinnikov (LO) theory of electronic instability in high velocity vortex motion has been applied to interpret the temperature dependence of the critical vortex velocity. The magnetic field dependence of the vortex critical velocity shows new features in the low-field regime not predicted by LO.

Activation of multiple cryptic donor splice sites by the common congenital afibrinogenemia mutation, FGA IVS4 + 1 G-->T.

Our recent studies on the molecular basis of the autosomal recessive disorder congenital afibrinogenemia showed that the most common mutation is a donor splice mutation in FGA intron 4, IVS4 + 1 G-->T, accounting for approximately half of disease alleles. The effect of this mutation on messenger RNA (mRNA) splicing, however, remained unproven. COS-7 cells transfected with a normal plasmid construct produced 100% mRNA molecules with correct splicing, whereas cells transfected with a mutant construct produced multiple aberrant mRNAs, due to utilization of cryptic donor splice sites situated in exon 4 and intron 4. One particular site situated 4 base pairs (bp) downstream of the normal site was used in 85% of transcripts causing afibrinogenemia by a 4-bp insertion-frameshift, leading to premature alpha-chain truncation. Our results confirm the utility of transfecting COS-7 cells to study mRNA splice-site mutations and demonstrate that the common FGA IVS4 variant is a null mutation leading to afibrinogenemia.

Prediction of preschool sensory and motor performance by 18-month neurologic scores among children born prematurely.

OBJECTIVES: Premature birth places a child at risk for a number of academic and behavioral deficits. The challenge currently facing interventionists is to identify at an early age those preterm children who will develop such deficits. Identified children can then be targeted for intervention to forestall deficits at school age. METHOD: This study examined the use of a neurologic assessment, administered at 18 months of age, to identify children who will have difficulties at preschool age. Premature children identified as neurologically normal or neurologically suspicious at the age of 18 months were tested with the Miller Assessment for Preschoolers. RESULTS: Although there was some variability in performance, as a group the children classified as neurologically suspicious at 18 months continued to fall into a risk category at 4 years of age. CONCLUSION: Because such categorization may predict inadequate performance during the school-age years, monitoring of the child's development is warranted.