Air bio-contamination control in hospital environment by UV-C rays and HEPA filters in HVAC systems.

The contamination of air-handling units is a widespread phenomenon in buildings with air-conditioning systems, including hospitals. The germicide capacity of UV-C rays is known and, in the air-conditioning apparatuses, the UV-C lamps are generally located inside the air ducts. Aim of the paper is to evaluate the effectiveness of UV-C lamps when they are differently placed, i.e. in a position to directly irradiate the HEPA filters surface. We built ad hoc experimental air-conditioning systems, with HEPA filters and UV-C lamps in the two described positions. The results obtained demonstrate that, for disinfection purpose, the direct irradiation of the HEPA filters by UV-C provides better results than irradiation of the air stream and the effectiveness increases when lowering the relative humidity of the air. The survival curves of the tested microorganisms (fungi) show typical tail shaped curves (two steps survival curves). Additional tests using both HEPA filters alone, and HEPA filters plus UV lamps, have been performed measuring the air pressure drop between entrance and exit the HEPA filters and collecting air samples in order to obtain total microbial and fungal count. The results obtained suggest that, at least in experimental conditions described, the radiation on filter surface reduces significantly the microbial load and the pressure drop through the filter, compared to a situation of not-irradiated HEPA filters.

Amplitude and phase modulation in microwave ring resonators by doped CVD graphene.

In this paper, we numerically and experimentally demonstrate how to modulate the amplitude and phase of a microwave ring resonator by means of few-layers chemical vapour deposition graphene. In particular, both numerical and experimental results show a modulation of about 10 dB and a 90 degrees-shift (quadrature phase shift) when the graphene sheet-resistance is varied. These findings prove once again that graphene could be efficiently exploited for the dynamically tuning and modulation of microwave devices fostering the realization of (i) innovative beam-steering and beam-forming systems and (ii) graphene-based sensors.

Optically transparent microwave screens based on engineered graphene layers.

We propose an innovative approach for the realization of a microwave absorber fully transparent in the optical regime. This device is based on the Salisbury screen configuration, which consists of a lossless spacer, sandwiched between two graphene sheets whose sheet resistances are different and properly engineered. Experimental results show that it is possible to achieve near-perfect electromagnetic absorption in the microwave X-band. These findings are fully supported by an analytical approach based on an equivalent circuital model. Engineering and integration of graphene sheets could facilitate the realization of innovative microwave absorbers with additional electromagnetic and optical functionalities that could circumvent some of the major limitations of opaque microwave absorbers.

Graphene-based perfect optical absorbers harnessing guided mode resonances.

We investigate graphene-based optical absorbers that exploit guided mode resonances (GMRs) attaining theoretically perfect absorption over a bandwidth of few nanometers (over the visible and near-infrared ranges) with a 40-fold increase of the monolayer graphene absorption. We analyze the influence of the geometrical parameters on the absorption rate and the angular response for oblique incidence. Finally, we experimentally verify the theoretical predictions in a one-dimensional, dielectric grating by placing it near either a metallic or a dielectric mirror, thus achieving very good agreement between numerical predictions and experimental results.

Graphene-based absorber exploiting guided mode resonances in one-dimensional gratings.

A one-dimensional dielectric grating, based on a simple geometry, is proposed and investigated to enhance light absorption in a monolayer graphene exploiting guided mode resonances. Numerical findings reveal that the optimized configuration is able to absorb up to 60% of the impinging light at normal incidence for both TE and TM polarizations resulting in a theoretical enhancement factor of about 26 with respect to the monolayer graphene absorption (≈2.3%). Experimental results confirm this behavior showing CVD graphene absorbance peaks up to about 40% over narrow bands of a few nanometers. The simple and flexible design points to a way to realize innovative, scalable and easy-to-fabricate graphene-based optical absorbers.

Nonlinear control of absorption in one-dimensional photonic crystal with graphene-based defect.

Perfect, narrow-band absorption is achieved in an asymmetric 1D photonic crystal with a monolayer graphene defect. Thanks to the large third-order nonlinearity of graphene and field localization in the defect layer we demonstrate the possibility to achieve controllable, saturable absorption for the pump frequency.

A compact evolved antenna for 5G communications.

Flexible and bendable electronics are gaining a lot of interest in these last years. In this scenario, compact antennas on flexible substrates represent a strategical technological step to pave the way to a new class of wearable systems. A crucial issue to overcome is represented by the poor radiation properties of compact antennas, especially in the case of flexible and thin substrates. In this paper, we propose an innovative design of a miniaturized evolved patch antenna whose radiation properties have been enhanced with a Split Ring Resonator (SRR) placed between the top and the ground plane. The antenna has been realized on a flexible and biocompatible substrate polyethylene naphthalate (PEN) of 250 µm by means of a new fabrication protocol that involves a three-layer 3D-inkjet printing and an alignment step. The antenna has been characterized in terms of the scattering parameter S11 and the radiation pattern showing a good agreement between simulations and measurements.

Optical filter with very large stopband (approximately 300 nm) based on a photonic-crystal vertical-directional coupler.

We have designed, fabricated, and demonstrated a vertical directional coupler based on the coupling between a polymer waveguide and a W1 photonic crystal waveguide. The filters have a bandwidth of approximately 2 nm within a stopband of Delta lambda approximately 300 nm and an on-chip insertion loss of 1 dB. This is the first (to our knowledge) demonstration of a filter with such a large stopband that overcomes the bandwidth limitation of existing filters.

Incomplete division of labor: error-prone multitaskers coexist with specialists.

Division of labor (DoL) occurs when individual members of a group specialize by performing particular tasks toward some common goal. Under complete DoL, every individual acts as a specialist and so performs only one kind of task. But under incomplete DoL, some individuals may act as generalists and so have the capacity to perform more than one kind of task. This persistence of generalists in the presence of specialists presents a theoretical challenge, particularly if generalists must pay an extra cost, an inefficiency penalty, for their capacity to perform more than one type of task. Prior work focused on how such costs tend to drive evolution toward complete DoL, with only specialists typically remaining at equilibrium [Wahl, L.M., 2002a. Evolving the division of labor: generalists, specialists and task allocation. J. Theoret. Biol. 219, 371-388; Wahl, L.M., 2002b. The division of labor: genotypic versus phenotypic specialization. Am. Nat. 160, 135-145]. Relaxing this key assumption, we show that generalists, despite paying some extra costs, can coexist with specialists. Relaxing another assumption, we also show that this coexistence can hold even when generalists often perform the wrong task. How can stable multitasking emerge despite this flawed decision-making? From the perspective that cognitive errors matter only when they translate into fitness decrements, we observe that error-prone generalists may persist most commonly in situations in which their mistakes do little to jeopardize group success. Our findings show that incomplete DoL can emerge even when generalists often err and must pay extra costs for their multitasking capacity.

Polymorphisms of the interleukin-1beta gene affect the risk of myocardial infarction and ischemic stroke at young age and the response of mononuclear cells to stimulation in vitro.

OBJECTIVE: To investigate the role of interleukin-1beta (IL-1beta) gene polymorphisms as a link between inflammation, coagulation, and risk of ischemic vascular disease at young age. METHODS AND RESULTS: A total of 406 patients with myocardial infarction (MI) at young age, frequency-matched for age, sex, and recruitment center, with 419 healthy population-based controls and 134 patients with ischemic stroke at young age, matched by age and sex, with 134 healthy population-based controls, were studied. Subjects carrying the TT genotype of the -511C/T IL-1beta polymorphism showed a decreased risk of MI (odds ratio [OR], 0.36; 95% CI, 0.20 to 0.64) and stroke (OR, 0.32; 95% CI, 0.13 to 0.81) after adjustment for conventional risk factors. In both studies, the T allele showed a codominant effect (P=0.0020 in MI; P=0.021 in stroke). Mononuclear cells from volunteers carrying the T allele showed a decreased release of IL-1beta and a decreased expression of tissue factor after stimulation with lipopolysaccharide compared with CC homozygotes. The presence of a monoclonal antibody against IL-1beta during cell stimulation resulted in a marked reduction of tissue factor activity expression. CONCLUSIONS: -511C/T IL-1beta gene polymorphism affects the risk of MI and ischemic stroke at young age and the response of mononuclear cells to inflammatory stimulation.

Detection of antigens recognized by a novel monoclonal antibody in tissue and serum from patients with breast cancer.

Monoclonal antibodies were produced in mice immunized with proteins released into tissue culture fluid of human breast cancer cells maintained in vitro. One monoclonal antibody (SP-2) identified a Mr 90,000 antigen which appears to be a proteolipid. In immunoperoxidase assays, SP-2 reacted with 81 of 90 specimens of human breast cancer. It also reacted with 12 of 23 cancers of nonbreast origin but was unreactive with all normal tissues tested. The Mr 90,000 antigen, purified by immunoaffinity chromatography using SP-2, was used in an indirect binding inhibition assay for the detection of antigen in human serum. With this assay, 35 of 69 patients with breast cancer and 11 of 37 patients with benign breast lesions showed serum antigen levels above 6 units/ml. Patients with nonbreast cancers also demonstrated elevated levels of antigen in 32% of cases. The SP-2 defined Mr 90,000 antigen appeared to be distinct from carcinoembryonic antigen and other monoclonal antibody-defined breast cancer antigens of similar molecular weight. SP-2 may prove useful as a serum and/or tissue marker in breast pathology.

Time domain analysis of optical amplification in Er3+ doped SiO2-TiO2 planar waveguide.

A time domain analysis of light amplification in an erbium doped silica-titania planar waveguide is reported. The investigation is performed by means of a home-made computer code which exploits the auxiliary differential equation scheme combined with the finite difference time domain technique to solve Maxwell's equations and the rate equations. The simulation model takes into account the pump and input signal propagation, the secondary transitions pertaining to the ion-ion interactions and exploits the optical, spectroscopic and geometrical parameters measured on the fabricated waveguide.

Refinement of Er3+-doped hole-assisted optical fiber amplifier.

This paper deals with design and refinement criteria of erbium doped hole-assisted optical fiber amplifiers for applications in the third band of fiber optical communication. The amplifier performance is simulated via a model which takes into account the ion population rate equations and the optical power propagation. The electromagnetic field profile of the propagating modes is carried out by a finite element method solver. The effects of the number of cladding air holes on the amplifier performance are investigated. To this aim, four different erbium doped hole-assisted lightguide fiber amplifiers having a different number of cladding air holes are designed and compared. The simulated optimal gain, optimal length, and optimal noise fig. are discussed. The numerical results highlight that, by increasing the number of air holes, the gain can be improved, thus obtaining a shorter amplifier length. For the erbium concentration NEr=1.8x1024 ions/m3, the optimal gain G(Lopt) increases up to ~2dB by increasing the number of the air holes from M=4 to M=10.

Differences in the glutathione system of cultured aortic smooth muscle cells from young and aged rats.

We studied the relation between the glutathione (GSH) system and cell proliferation in a model of smooth muscle cells (SMC) derived from the thoracic aorta of 4-6-week-old (young) and 15-month-old (aged) rats. SMC from aged rats showed greater levels of total non-protein thiol compounds (T-SH), increased glutathione transferase (GST) and increased glutathione reductase (GSSG-Red) activities compared with cells from young rats. These changes were associated with an increased proliferation rate of SMC from aged rats. To evaluate the role of GSH on cell proliferation better, a specific inhibitor of gamma-glutamyl-cystein synthetase, DL-buthionine-SR-sulphoximine (BSO) was used. BSO showed a dose-dependent inhibition of cell growth, with an IC50 of 10(-4) M, after 48-72 h of incubation. Removal of BSO restored cell growth, further suggesting a link between GSH levels and vascular cell proliferation. The inhibitory effect of BSO was about two times greater on SMC from young than on SMC from aged rats. BSO showed 56% inhibition on the proliferation of SMC from young rats and 32% inhibition on SMC from aged rats (10(-4) M, 72 h of incubation). A parallel reduction of GSH levels of 38% and 19% for SMC from young and aged rats, respectively, was observed, suggesting that age-related factors may influence the involvement of GSH system in cell proliferation.

Genetic modulation of coagulation factor VII plasma levels: contribution of different polymorphisms and gender-related effects.

We studied the relationships among different polymorphisms of FVII gene in determining FVII levels, in a sample of 335 male and female Italian volunteers. The hypervariable region 4 (HVR4), the promoter decanucleotide insertion (-323 0/10 bp) and the R353Q polymorphisms of FVII gene were evaluated. The association of HVR4 or -323 0/10 bp polymorphism with plasma FVII levels differed between gender (Interaction term: p = 0.02 and p = 0.03, respectively), showing stronger effect in males than in females. In males, the R353Q and the HVR4 polymorphisms showed an incremental influence on FVII variance (F = 8.9, p <0.001 and F = 4.4, p = 0.01, respectively). Moreover, the effects of Q and 10 bp alleles on the reduction of FVII activity levels were significantly potentiated by the presence of H7 allele of HVR4 (Interaction term p = 0.03 for R353Q*HVR4 and p = 0.03 for -323 0/10 bp*HVR4). In conclusion, the effect of FVII polymorphisms on FVII levels was gender dependent and derived from a complex interaction among them. The HVR4 polymorphism seems to add an independent, albeit small, contribution to the regulation of FVII plasma levels.

4G/5G promoter PAI-1 gene polymorphism is associated with plasmatic PAI-1 activity in Italians: a model of gene-environment interaction.

The PAI-1 gene promoter 4G/5G polymorphism was found to be associated with plasma PAI-1 activity in Northern and Central Europe populations, but no data are available on the association between this polymorphism and PAI-1 levels in Southern Europe countries (such as Italy) where the incidence of ischemic disorders is lower. This study shows that among populations with different incidence of atherothrombotic disorders the 4G/5G PAI-1 gene promoter polymorphism has the same importance in the regulation of plasma PAI-1 activity. Moreover, we have analysed some gene-environmental interactions: the correlation between PAI-1 and cholesterol in non dyslipidemic subjects and the correlation between PAI-1 activity and tryglicerides in dyslipidemic subjects differed according to the 4G/5G genotype class. Thus, our findings suggest that, among subjects with or without metabolic disorders such as dyslipidemia, completely different gene-environment interactions may occur.

Helicobacter pylori infection and the risk of myocardial infarction: role of fibrinogen and its genetic control.

The contribution of Helicobacter pylori (HP) infection to the risk of myocardial infarction was evaluated. The role of fibrinogen and its genetic control as a possible mechanism by which HP may influence myocardial infarction risk was explored in this context. A case-control study was performed in 101 patients with myocardial infarction and in 101 controls. HP infection was associated with an increased risk of myocardial infarction independently for confounding variables (OR 4.1, CI95: 1.8-9.4). HP infection was significantly associated with higher levels of fibrinogen, both in cases and in controls. Furthermore, there was an additive effect of HP infection and B2 allele of BclI fibrinogen polymorphism in increasing fibrinogen levels. HP infection showed a stronger effect on the risk of myocardial infarction in B2 allele carriers (OR 7.6, CI95: 1.8-31.6) as compared to subjects carrying the B1B1 genotype (OR 3.3, CI95: 1.2-9.2). We showed that a previous HP infection is a risk factor for myocardial infarction. An increase in fibrinogen levels is a possible mechanism by which HP may act. Concomitant conditions, like a genetic predisposition in increasing fibrinogen levels, seem to further increase the effect of HP on myocardial infarction risk.

Photonic band gap filter for wavelength division multiplexer.

An optical multiplexer-demultiplexer based on an index-confined photonic band gap waveguide is proposed. The dropping of electromagnetic waves having a given frequency or a certain frequency band is obtained via a phase-shifted grating obtained by breaking the uniform period sequence to include a defect layer. The selective filtering properties of the proposed structure are simulated by means of a computer code relying on a bi-directional beam propagation method based on the method of lines.

The decanucleotide insertion/deletion polymorphism in the promoter region of the coagulation factor VII gene and the risk of familial myocardial infarction.

Recently, an association has been found between factor VII polymorphisms and the risk of familial myocardial infarction. To obtain a thorough evaluation of the influence of factor VII gene on the risk of myocardial infarction, we extended our analysis to the role of a decanucleotide insertion/deletion functional polymorphism (-323 0/10-bp) in the promoter region of factor VII and to possible interactions with the HVR4 intron polymorphism. We performed a case-control study of 176 patients with myocardial infarction, over 45 years, who had a familial history of arterial thrombosis and 227 control subjects without a personal or family history of cardiovascular disease. The frequency of the rare allele of 10 bp was lower in cases (0.14 95% CI, 0.10-0.17) than in controls (0.19 95% CI, 0.16-0.23; chi(2)=4.7, p=0.03). Allowing for Hardy-Weinberg equilibrium in controls and testing for association under restricted maximisation, there was a significant difference in genotype frequency between cases and controls (p=0.02). Carriers of the 10-bp allele had an odds ratio for myocardial infarction of 0.65 (95% CI, 0.37-1.12), in multivariate logistic regression analysis. Combination analysis of -323 0/10-bp and HVR4 polymorphisms shows half reduction in the risk of myocardial infarction in comparison with the reference group for all the other groups, suggesting that there was no additivity between the effect of the 10-bp and the H7 alleles. Our findings suggest that the promoter polymorphism of factor VII gene may influence the risk of familial myocardial infarction.

Immunohistochemical study in a case of primitive lymphoma of the uterine cervix.

An immunohistochemical study using the peroxidase-antiperoxidase technique was conducted in a case of primitive lymphoma of the uterine cervix. The antibodies used were: epithelial membrane antigen, leucocyte common antigen, Lambda, Kappa, lysozome and alpha 1-antichymotripsine. A positive reaction for leucocyte common antigen and Lampda demonstrated a B-cell plasmacytoid lymphocytic lymphoma, a tumour of haemopoietic origin.