Variable-gain up-converter with current reuse for 5-GHz WLAN applications

A variable-gain up-conversion mixer for 5-GHz WLAN applications is presented, whose input stage is based on a novel variable gain transconductor. The proposed topology features reduced power consumption by exploiting dc current reuse for mixer biasing. Moreover, a new low-consumption control circuit is introduced, which achieves a temperature-stable and linear-in-dB characteristic, providing a 40-dB dynamic range within ±1 dB gain error.     

Macrophage-derived cytokines in the follicular fluids of women with infertility due to immunological causes. Elevated levels of interleukin 6 and low levels of granulocyte-macrophage colony-stimulating factor

Myoclonus of the middle ear is a rare condition characterized by abnormal repetitive muscle contractions of the tympanic cavity. In this paper we describe what we believe is the first reported case of continuous high-frequency objective tinnitus caused by middle ear myoclonus. During exploratory tympanomastoidectomy it was hypothesized that a small dural arteriovenous malformation not identified on previous tests was the cause of the tinnitus. However, complete disappearance of the tinnitus during administration of curare for anesthesia led us to believe that the tinnitus might have been caused by myoclonus of the middle ear. Sectioning of the stapedius and tensor tympani tendons rendered the patient asymptomatic and confirmed the diagnosis of middle ear myoclonus. At follow-up of one year, the patient's quality of life had improved substantially; the tinnitus did not recur and she no longer had vertigo.     

An Implicit Multistage Integration Method Including Projection for the Numerical Simulation of Constrained Multibody Systems

To be efficient, the simulation of multibody system dynamics requires fast and robust numerical algorithms for the time integration of the motion equations usually described by Differential Algebraic Equations (DAEs). Firstly, multistep schemes especially built up for second-order differential equations are developed. Some of them exhibit superior accuracy and stability properties than standard schemes for first-order equations. However, if unconditional stability is required, one must be satisfied with second-order accurate methods, like one-step schemes from the Newmark family.Multistage methods for which high accuracy is not contradictory with stringent stability requirements are then addressed. More precisely, a two-stage, third-order accurate Implicit Runge–Kutta (IRK) method which possesses the desirable properties of unconditional stability combined with high-frequency dissipation is proposed.Projection methods which correct the integrated estimates of positions, velocities and accelerations are suggested to keep the constraint equations satisfied during the numerical integration. The resulting time integration algorithm can be easily implemented in existing incremental/iterative codes. Numerical results indicate that this approach compares favourably with classical methods.     

Quantification in positron emission mammography (PEM) with planardetectors: contrast resolution measurements using a custom breastphantom and novel spherical hot-spots

The authors have previously demonstrated that their Positron Emission Mammography-1 (PEM-1) system can successfully detect small (<2 cm diameter) tumors. Images in the current system are judged qualitatively for the presence of focal uptake of ¹⁸F-FDG. The authors are presently taking steps toward quantifying the emission images. To this end they have constructed a breast phantom and developed a novel technique for fabricating very small wall-less radioactive hot-spots. The hot-spots are made by adding ¹⁸F-FDG to a 25 mg/cc solution of Agarose in water. The heated solution is poured into spherical molds which are separated upon congealing to yield robust wall-less radioactive hot-spots. The hot-spots were uniform to within 1-5 parts in 100. Less than 0.1% of the total hot-spot activity leaked into the background in 30 minutes. Contrast resolution experiments have been performed with 12 mm and 16 mm diameter hot-spots in the breast phantom containing water with various amounts of background activity. In both cases, the observed contrast values agree well with the ideal values. In the case of the 12 mm hot-spot with a 350-650 keV energy window, image contrast differed from the ideal by an average of 11%. The image contrast for 12 mm hot-spot improved by 40% and the number of detected events decreased by 35% when the low energy threshold was increased from 300 keV to 450 keV     

2-Phenyloxazole-4-carboxamide as a Scaffold for Selective Inhibition of Human Monoamine Oxidase B

A series of 2-phenyloxazoles bearing an amide group at position 4 were designed and synthesized for evaluation as potential inhibitors of human recombinant monoamine oxidases (hrMAOs). Results of kinetics experiments demonstrated that all compounds behave as competitive MAO inhibitors, with good selectivity toward the MAO-B isoform. The most potent and selective derivatives are characterized by inhibition constant (K_i) values in the sub-micromolar range and a good selectivity index (K_{i MAO-A}/K_{i MAO-B}>50). Some derivatives were also found to be able to inhibit MAO activity in nerve growth factor (NGF)-differentiated PC12 cells, taken as a model of neuronal cells. In particular, 2-(2-hydroxyphenyl)-N-phenyloxazole-4-carboxamide (compound 4 a ) may be a promising new scaffold, exerting the highest selectivity and inhibitory effect toward MAOs in NGF-differentiated PC12 cell lysates, without compromising cell viability. Molecular docking analysis allowed a rationalization of the experimentally observed binding affinity and selectivity.     

Obesity and Male Reproduction: Do Sirtuins Play a Role?

Obesity is a major current public health problem of global significance. A progressive sperm quality decline, and a decline in male fertility, have been reported in recent decades. Several studies have reported a strict relationship between obesity and male reproductive dysfunction. Among the many mechanisms by which obesity impairs male gonadal function, sirtuins (SIRTs) have an emerging role. SIRTs are highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases that play a role in gene regulation, metabolism, aging, and cancer. SIRTs regulate the energy balance, the lipid balance, glucose metabolism, and adipogenesis, but current evidence also indicates a role for SIRTs in male reproduction. However, the majority of the studies have been conducted in animal models and very few have been conducted with humans. This review shows that SIRTs play an important role among the molecular mechanisms by which obesity interferes with male fertility. This highlights the need to deepen this relationship. It will be of particular interest to evaluate whether synthetic and/or natural compounds capable of modifying the activity of SIRTs may also be useful for the treatment of obesity and its effects on gonadal function. Although few studies have explored the role of SIRT activators in obesity-induced male infertility, some molecules, such as resveratrol, appear to be effective in modulating SIRT activity, as well as counteracting the negative effects of obesity on male fertility. The search for strategies to improve male reproductive function in overweight/obese patients is a challenge and understanding the role of SIRTs and their activators may open new interesting scenarios in the coming years.     

Peptides Derived from Angiogenin Regulate Cellular Copper Uptake

The angiogenin protein (ANG) is one of the most potent endogenous angiogenic factors. In this work we characterized by means of potentiometric, spectroscopic and voltammetric techniques, the copper complex species formed with peptide fragments derived from the N-terminal domain of the protein, encompassing the sequence 1-17 and having free amino, Ang1-17, or acetylated N-terminus group, AcAng1-17, so to explore the role of amino group in metal binding and cellular copper uptake. The obtained data show that amino group is the main copper anchoring site for Ang1-17. The affinity constant values, metal coordination geometry and complexes redox-potentials strongly depend, for both peptides, on the number of copper equivalents added. Confocal laser scanning microscope analysis on neuroblastoma cells showed that in the presence of one equivalent of copper ion, the free amino Ang1-17 increases cellular copper uptake while the acetylated AcAng1-17 strongly decreases the intracellular metal level. The activity of peptides was also compared to that of the protein normally present in the plasma (wtANG) as well as to the recombinant form (rANG) most commonly used in literature experiments. The two protein isoforms bind copper ions but with a different coordination environment. Confocal laser scanning microscope data showed that the wtANG induces a strong increase in intracellular copper compared to control while the rANG decreases the copper signal inside cells. These data demonstrate the relevance of copper complexes’ geometry to modulate peptides’ activity and show that wtANG, normally present in the plasma, can affect cellular copper uptake.     

Olive mill wastewaters decontamination based on organo-nano-clay composites

Green composites for environmental applications were successfully prepared by intercalation of the biosurfactant Quillaja saponin onto montmorillonite mineral clay on varying pH and surfactant/clay ratio. Equilibrium adsorption isotherms were constructed and the system was characterized by performing TGA and XRD analyses.The efficiency of the surfactant-modified clay in the removal of the organic content present in olive mill wastewaters (OMW) was evaluated by means of spectrophotometric measurements. The interest for this cogent issue comes from the consideration that, despite their high pollutant content, OMW can be considered as a potential resource of several organic compounds which can be recovered for a wide array of pharmaceutical and industrial applications. Two different strategies were proposed. In the first one, dried surfactant/clay hybrids were added to the batch samples under continuous stirring, while in the second alternative approach the organoclays were packed in chromatography column filled with multiple alternate layers of sand and organoclay.These studies revealed the efficacy of the methods used and suggested that the modification of the montmorillonite clay substrate significantly improves the performance of the clay.     

Quantification of glistenings in intraocular lenses using a ballistic-photon removing integrating-sphere method

An alternative method for quantification of glistenings in intraocular lenses (IOLs) using an integrating sphere with an adjustable back aperture to remove ballistic photons is presented. Glistenings in soft IOLs have been known for more than a decade; however, their severity and visual impact are still under investigation. A number of studies have been made to quantitatively describe glistenings in IOLs. Quantization and precise grading of IOLs will provide needed information to evaluate the severity and visual impact of glistenings in patients. We investigated the use of a simple modification of an integrating-sphere method to eliminate ballistic photons to quantitatively measure scattered light from glistenings in IOLs. The method described in this paper provides a simple and effective way to quantitatively characterize glistenings in vitro. It may be especially useful to quantify scattering associated with low-grade glistenings where the density of the scattering centers is low. Finally, the modified integrating-sphere method may also be generally applicable to quantitatively characterize scattering from other optical media.     

How Can We Improve Vaccination Response in Old People? Part I: Targeting Immunosenescence of Innate Immunity Cells

Vaccination, being able to prevent millions of cases of infectious diseases around the world every year, is the most effective medical intervention ever introduced. However, immunosenescence makes vaccines less effective in providing protection to older people. Although most studies explain that this is mainly due to the immunosenescence of T and B cells, the immunosenescence of innate immunity can also be a significant contributing factor. Alterations in function, number, subset, and distribution of blood neutrophils, monocytes, and natural killer and dendritic cells are detected in aging, thus potentially reducing the efficacy of vaccines in older individuals. In this paper, we focus on the immunosenescence of the innate blood immune cells. We discuss possible strategies to counteract the immunosenescence of innate immunity in order to improve the response to vaccination. In particular, we focus on advances in understanding the role and the development of new adjuvants, such as TLR agonists, considered a promising strategy to increase vaccination efficiency in older individuals.