611 research outputs found
Nano-antenna array for high efficiency sunlight harvesting
none5noSolar rectennas are promising devices for energy harvesting. Capability of rectennas to convert incident light into useful energy depends on the antenna efficiency, that is the ratio between the power transferred to the load vs the incoming power. In this work, we first emphasize that for the efficiency to be calculated accurately, antennas need to be treated as receiving devices, not as transmitting ones. Then, we propose an arrangement of antennas that differs from those published so far in three respects: (1) the proposed arrangement is formed by an array of nano-antennas with sub-wavelength inter-element spacing, (2) it comprises a reflecting mirror, and (3) it allows for dual polarization operation. Through numerical simulations, we show that the small lattice pitch we use is responsible for frequency flattening of the lattice impedance over the whole solar spectrum, eventually allowing for excellent matching with the antennas’ loads. Also, the small pitch allows for a smooth dependence of the receiving efficiency on the angle of incidence of sunlight. Finally, we show numerically that the reflecting mirror also allows for an almost complete cancellation of light scattered by the receiving antennas. The final result is a polarization insensitive receiving theoretical efficiency larger than 70% over the whole 300-3000 nm spectral range, with a less than 10% energy wasting due to back-scattering of sunlight.openMidrio M.; Pierantoni L.; Boscolo S.; Truccolo D.; Mencarelli D.Midrio, M.; Pierantoni, L.; Boscolo, S.; Truccolo, D.; Mencarelli, D
Porencephaly in an Italian neonate with foetal alcohol spectrum disorder: A case report
INTRODUCTION: Foetal alcohol spectrum disorder (FASD) is a complex malformative disease caused by the teratogenic effect of alcohol consumed during pregnancy. Mothers are frequently reluctant to admit alcohol consumption during pregnancy. During infancy and particularly during neonatal period, differential diagnosis is difficult. PATIENT CONCERNS: This case is represented by an Italian neonate boy small for gestational age, born by caesarean section at a gestational age of 37 weeks + 6 days by neglect and single-parent pregnancy. On physical examination, he presented particular facial features: microcephaly, epicanthal folds, flat midface, low nasal bridge, indistinct philtrum, and thin upper lip; moreover, examination revealed a macro-penis and recurvation without evidence of glans. DIAGNOSIS: Echocardiogram showed an inter-ventricular defect of medium-muscular type and brain magnetic resonance imaging showed asymmetry of the cerebral hemispheres with hypoplasia of the left cerebral hemisphere, dilatation of the left ventricle, cerebrospinal fluid cavity, and porencephaly. INTERVENTIONS: We investigated the ethylglucuronide (EtG) concentration in the neonate's hair by liquid chromatography-tandem mass spectrometry and we detected EtG in the infant's hair (normal value, 30 pg/mg), demonstrating prenatal alcohol exposure. OUTCOMES: In this neonate, EtG measure in hairs permitted the diagnosis of FASD, so allowing to exclude genetic diseases associated with similar clinical findings. After this result the mother admitted that she drunk alcohol during pregnancy (she declared 3 glasses of wine every day). At the age of 6 months, the child showed a moderate neurodevelopmental delay. CONCLUSION: This case shows that FAD should be considered in neonates with rare neurological diseases as porencephaly. In neonates and infants born to a mother who did not report alcohol use, EtG measure in hairs can significantly improve diagnosis of FASD, so allowing to exclude genetic diseases associated with similar clinical findings
Postharvest Ozone Fumigation of Grapes (cv Sangiovese) Differently Affects Volatile Organic Compounds and Polyphenol Profiles of Berries and Wine
Consumers are more and more oriented towards the purchase of safer food and beverages, which is pushing the wine sector to find alternatives to the use of sulfur dioxide. Ozone (O3) is already applied in the wine industry to produce sulfur dioxide-free wines through the patented method Purovino®. The aim of this two-year study was that of evaluating whether the postharvest treatment of grapes with ozone affects volatile organic compounds (VOCs) and polyphenol profile in berries, and in turn, wine composition. Grape bunches (Vitis vinifera L.) of cv Sangiovese were fumigated overnight with gaseous ozone (max 20 g·h−1 with 6% w.w−1 of ozone) in a cold room at 4°C (±0.5). After treatment, grapes were processed into wine. In grapes, ozone treatments increased total polyphenol and flavonoid content and upregulated specific genes (phenylalanine ammonia lyase, VvPAL, flavanol synthase 1, and VvFLS1) involved in polyphenol biosynthesis. Wine obtained from ozone-treated grapes had higher flavanol content than the control. Fumigation only slightly affected the different VOC classes of grapes and wine, including aroma compounds derived from the lipoxygenase (LOX) pathway. Although a season-dependent effect was observed, results showed that postharvest ozone treatments applied to avoid the use of sulfur dioxide introduced limited but, in general, positive modifications to grape and wine composition. This information provides assurance to winemakers that the maintenance of wine quality and typicity will be guaranteed when using ozone treatments
Optimizing transcranial magnetic stimulation for spaceflight applications
As space agencies aim to reach and build installations on Mars, the crews will face longer exposure to extreme environments that may compromise their health and performance. Transcranial magnetic stimulation (TMS) is a painless non-invasive brain stimulation technique that could support space exploration in multiple ways. However, changes in brain morphology previously observed after long-term space missions may impact the efficacy of this intervention. We investigated how to optimize TMS for spaceflight-associated brain changes. Magnetic resonance imaging T1-weighted scans were collected from 15 Roscosmos cosmonauts and 14 non-flyer participants before, after 6 months on the International Space Station, and at a 7-month follow-up. Using biophysical modeling, we show that TMS generates different modeled responses in specific brain regions after spaceflight in cosmonauts compared to the control group. Differences are related to spaceflight-induced structural brain changes, such as those impacting cerebrospinal fluid volume and distribution. We suggest solutions to individualize TMS to enhance its efficacy and precision for potential applications in long-duration space missions. © 2023, The Author(s)
Local and Distributed fMRI Changes Induced by 40 Hz Gamma tACS of the Bilateral Dorsolateral Prefrontal Cortex: A Pilot Study
Over the past few years, the possibility of modulating fast brain oscillatory activity in the gamma (γ) band through transcranial alternating current stimulation (tACS) has been discussed in the context of both cognitive enhancement and therapeutic scenarios. However, the effects of tACS targeting regions outside the motor cortex, as well as its spatial specificity, are still unclear. Here, we present a concurrent tACS-fMRI block design study to characterize the impact of 40 Hz tACS applied over the left and right dorsolateral prefrontal cortex (DLPFC) in healthy subjects. Results suggest an increase in blood oxygenation level-dependent (BOLD) activity in the targeted bilateral DLPFCs, as well as in surrounding brain areas affected by stimulation according to biophysical modeling, i.e., the premotor cortex and anterior cingulate cortex (ACC). However, off-target effects were also observed, primarily involving the visual cortices, with further effects on the supplementary motor areas (SMA), left subgenual cingulate, and right superior temporal gyrus. The specificity of 40 Hz tACS over bilateral DLPFC and the possibility for network-level effects should be considered in future studies, especially in the context of recently promoted gamma-induction therapeutic protocols for neurodegenerative disorders. © 2022 Lucia Mencarelli et al
Novelty of Italian Grape Ale (IGA) beer: Influence of the addition of Gamay macerated grape must or dehydrated Aleatico grape pomace on the aromatic profile
: A new category of fruit style beer resulting from the addition of grape matrices is named Italian Grape Ale (IGA). In this paper, we report data on an experimental work to produce IGA beers, adding macerated (CO2 or N2) red Gamay grape must or Aleatico grape pomace resulting from a grape dehydration process. Our hypothesis, that these wine processes can produce volatile organic compounds (VOCs) to characterize these IGA beers which was confirmed by chemical, sensory and aromatic results. IGA beers especially the one with gas-macerated grape musts (IGA-C and IGA-N) showed higher alcohol content than ALE beer (Control) and a higher polyphenol content and antioxidant activity. As regards VOCS, IGA beers increased the concentration of some classes (i.e., alcohols, esters, norisoprenoids) and IGA-N was better characterized by specific compounds such as isobutyric acid, phenylacetate, tyrosol, ethyl hydrogen succinate. Finally, E-nose and sensory evaluation discriminated significantly all the IGA beers
Juvenile moyamoya and craniosynostosis in a child with deletion 1p32p31: Expanding the clinical spectrum of 1p32p31 deletion syndrome and a review of the literature
Moyamoya angiopathy (MA) is a rare cerebrovascular disorder characterised by the progressive occlusion of the internal carotid artery. Its aetiology is uncertain, but a genetic background seems likely, given the high MA familial rate. To investigate the aetiology of craniosynostosis and juvenile moyamoya in a 14-year-old male patient, we performed an array-comparative genomic hybridisation revealing a de novo interstitial deletion of 8.5 Mb in chromosome region 1p32p31. The deletion involved 34 protein coding genes, including NF1A, whose haploinsufficiency is indicated as being mainly responsible for the 1p32-p31 chromosome deletion syndrome phenotype (OMIM 613735). Our patient also has a deleted FOXD3 of the FOX gene family of transcription factors, which plays an important role in neural crest cell growth and differentiation. As the murine FOXD3-/- model shows craniofacial anomalies and abnormal common carotid artery morphology, it can be hypothesised that FOXD3 is involved in the pathogenesis of the craniofacial and vascular defects observed in our patient. In support of our assumption, we found in the literature another patient with a syndromic form of MA who had a deletion involving another FOX gene (FOXC1). In addition to describing the clinical history of our patient, we have reviewed all of the available literature concerning other patients with a 1p32p31 deletion, including cases from the Decipher database, and we have also reviewed the genetic disorders associated with MA, which is a useful guide for the diagnosis of syndromic form of MA
Enhancement of lysosomal glycohydrolase activity in human primary B lymphocytes during spontaneous apoptosis.
It has been shown that lysosomes are involved in B cell apoptosis but lysosomal glycohydrolases have never been investigated during this event. In this study we determined the enzymatic activities of some lysosomal glycohydrolases in human tonsil B lymphocytes (TBL) undergoing in vitro spontaneous apoptosis. Fluorimetric methods were used to evaluate the activities of β-hexosaminidases, α-mannosidase, β-mannosidase, β-galactosidase, β-glucuronidase and α-fucosidase. Results show that in TBL during spontaneous apoptosis, there is a significant increase in the activity of β-hexosaminidases, α-mannosidase, β-mannosidase and β-galactosidase. Also β-glucuronidase and α-fucosidase activities increase but not in a significant manner. Further studies on β-hexosaminidases revealed that also mRNA expression of the α- and β-subunits, which constitute these enzymes, increases during spontaneous TBL apoptosis. When TBL are protected from apoptosis by the thiol molecule N-acetyl-L-cysteine (NAC), there is no longer any increase in glycohydrolase activities and mRNA expression of β-hexosaminidase α- and β-subunits. This study demonstrates for the first time that the activities and expression of some lysosomal glycohydrolases are enhanced in TBL during spontaneous apoptosis and that these increases are prevented when TBL apoptosis is inhibited
Graphene-based Electronically Tuneable Microstrip Attenuator
This paper presents the design of a graphene-based electronically tuneable microstrip attenuator operating at a frequency of 5 GHz. The use of graphene as a variable resistor is discussed and the modelling of its electromagnetic properties at microwave frequencies is fully addressed. The design of the graphene-based attenuator is described. The structure integrates a patch of graphene, whose characteristics can range from being a fairly good conductor to a highly lossy material, depending on the applied voltage. By applying the proper voltage through two high-impedance bias lines, the surface resistivity of graphene can be modified, thereby changing the insertion loss of the microstrip attenuator
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