Statistics of transverse mode turn-on dynamics in VCSELs

The turn-on process of a multimode VCSEL is investigated from a statistical point of view. Special attention Is paid to quantities such as time jitter and bit error rate. The single-mode performance of VCSELs during current modulation is compared to that of edge-emitting lasers     

Responsiveness of the major birch allergen Bet v 1 scaffold to the gastric environment: Impact on structure and allergenic activity

Scope: Four Bet v 1 homologous food allergens from celeriac (rApi g 1), apple (rMal d 1), peach (rPru p 1) and hazelnut (rCor a 1), were used to probe the structural responsiveness of the Bet v 1 scaffold to gastric digestion conditions and its impact on allergenicity. Methods and results: Low pH induced conformational changes of all homologues, which was reduced at physiological ionic strength for all except rPru p 1 as observed by circular dichroism (CD)‐spectroscopy. The homologues were rapidly digested by pepsin, losing their IgE binding activity, although the kinetics and patterns of digestion varied subtly between homologues, rApi g 1 being the most stable. We have demonstrated for the first time that gastric phosphatidyl‐choline (PC) induced conformational changes in all homologues but only rMal d 1 penetrated the PC vesicles as detected by fluorescence polarization, slowing its digestion and retaining more of its allergenic activity. PC enhanced basophil activation of all digested allergens except rApi g 1. Conclusion: The Bet v 1 scaffold is generally susceptible to low pH and pepsinolysis and interacts with PC vesicles, properties which can explain effects of the gastric environment on their allergenicity. These data show the importance of including surfactants in model digestion systems.     

Effect of pan-frying in extra-virgin olive oil on odour profile, volatile compounds and vitamins

Changes in odour of Arauco (ARA) and Arbequina (ARB) extra-virgin olive oil (OO) were monitored during frying by electronic nose (EN) and solid-phase microextraction–gas chromatography methodologies. Degradation of α- and γ-tocopherols was monitored by HPLC. Electronic nose data and volatile compounds were analysed at intervals of 15 min ( t ₁₅) during 60 min of frying ( t ₆₀). α- and γ-tocopherols were determined at intervals of 5 min ( t ₅) during 30 min of frying ( t ₃₀). Principal components analysis applied to EN data showed one component, PC₁ which accounted 96.6% of the total odour variation. SnO₂ sensors had a positive correlation with PC₁. ARA variety corresponding to frying t ₆₀ had the highest positive correlation with PC_1. Analysis of variance results for volatile compounds showed an increase on production for: 3-methyl butanal, n -pentanal, n -hexanal, n -heptanal and n -nonanal at 15 min of frying for ARB OO and at 30 min for ARA OO. α-tocopherol and γ-tocopherol showed an important decrease after the first 5 min of frying for ARB OO and at 15 min for ARA OO.     

A study of Ga3+ Reduction in the drop mercury electrode

A kinetic study is carried out of the Ga^3? + 3e → Ga electrode reaction in relation to the existing ionic species in the media used: LiClO₄, NaCl, KBr, NaNO₃, Na₂SO₄ and NH₄OH. It is found that the predominant species in equilibrium at the electrode have a coordination index of 6 ligands for the SO^?₄, the Cl^? and NO^?₃ ions, 5 for Br^? and 4 for NH₃. It is also noted that Ga³⁺ does not form complex compounds with ClO^?4 ions. The specific rate constant of electrode reaction in the equilibrium potential, k_O calculated by Koutecky's method, is in all cases between 2·10^?5 and 1·10^?8 cm s^?1, and the transfer coefficient, α, is about 0·15.By microcoulometric methods it is confirmed that the number of electrons in the electron transfer is three.A study is also made of interaction of the Ga³⁺ reduction wave, which in a 0·1 M LiClO₄ medium presents a half wave potential (E_{$\text{1}\text{2}$}) of ?1·270 V with reference to sce, with the H⁺ wave. It is concluded that the optimum pH of study is between 2·7 and 3·1. The ionic intensity of the medium is also taken into account.     

‘Best before period once opened’ for honey samples from oceanic climates on the basis of their acidity types

Stability of food is of particular interest, as we should know the period for which a given food maintains its original quality. Acidity is a very important parameter as regards honey quality control. In this study we analysed a possible ‘best before period once opened’, regarding the evolution of acidity in honey throughout 30 months in samples from regions with oceanic climates. The study was carried out at room temperature (between 15 and 25 °C) by analysing all samples in duplicate each 5 months. We also researched the possible influence of induced granulation on the acidity evolution of honey samples, observing that as the analysis of variance showed significant differences at P‐value <0.05, this process had a significant influence on free acid and total acidity. All samples fulfilled the European Regulations regarding free acid, because no honey sample showed a free acid value higher than the limit of 50 meq kg^?1. Nevertheless, all honey samples suffered a continuous decrease of pH from 20 months on (averages: from 4.1 ± 0.25 at 20 months to 4.0 ± 0.23 at 30 months), and a continuous increase of both free acid (averages: from 27.6 ± 6.22 meq kg^?1 at 20 months to 33.5 ± 6.44 meq kg^?1 at 30 months) and total acidity (averages: from 42.5 ± 7.60 meq kg^?1 at 20 months to 44.7 ± 7.60 meq kg^?1 at 30 months). On the basis of acidity types, 20 months should be considered the ‘best before period once opened’ for honey from regions with oceanic climates.     

A multiplier evaluation of primary factors supply–shocks in a regional economy

Demand-side multipliers have ruled within multisectorial models as the main indicators for policy effectiveness and key-sector determination both in linear interindustry analysis and in non-linear applied general equilibrium models. In this paper we shift the perspective to supply-side injections by studying the effects of marshalling additional primary factors (K, L) that give rise to a general resource reallocation. We obtain estimates of supply multipliers by numerically approximating the underlying and unobservable general equilibrium Jacobian matrix. These estimates provide complementary information to standard demand multipliers. We illustrate the methodology using an empirical general equilibrium model for the region of Andalusia, Spain.     

Iatrogenic diaphragmatic hernia following abdominal esophagogastrofundoplication: report of a case

The authors describe diagnosis and surgical treatment of a patient with iatrogenic diaphragmatic hernia following esophagogastrofundoduplication by Nissen's operation. The patient had presented a hiatal hernia with esophagitis chronic regurgitation and was submitted to esophagogastrofundoduplication. On the third postoperative day, the patient showed signs of dysphagia and intense dyspnea. The computerized tomography showed the presence of the gastric fundus and it's contents inside the leftpleural cavity. The patient was submitted to a left posterolateral thoractomy and an ischemic peptic ulcer in the gastric fundus, blocked by lung parenchyma was sutured. Then, the stomach was reduced into the abdominal cavity with diaphragmatic suture associated with esophageal and gastric fundus fixation to the right diaphragmatic pilar. The patient presented satisfactory immediate and late postoperative follow-up (1 year). The authors discuss and document aspects of diagnosis as well as surgical indication.