A Group-Theoretic Approach to the Origin of Chirality-Induced Spin-Selectivity in Nonmagnetic Molecular Junctions.

Spin-orbit coupling gives rise to a range of spin-charge interconversion phenomena in nonmagnetic systems where certain spatial symmetries are reduced or absent. Chirality-induced spin-selectivity (CISS), a term that generically refers to a spin-dependent electron transfer in nonmagnetic chiral systems, is one such case, appearing in a variety of seemingly unrelated situations ranging from inorganic materials to molecular devices. In particular, the origin of CISS in molecular junctions is a matter of an intense current debate. Here, we derive a set of geometrical conditions for this effect to appear, hinting at the fundamental role of symmetries beyond otherwise relevant quantitative issues. Our approach, which draws on the use of point-group symmetries within the scattering formalism for transport, shows that electrode symmetries are as important as those of the molecule when it comes to the emergence of a spin-polarization and, by extension, to the possible appearance of CISS. It turns out that standalone metallic nanocontacts can exhibit spin-polarization when relative rotations which reduce the symmetry are introduced. As a corollary, molecular junctions with achiral molecules can also exhibit spin-polarization along the direction of transport, provided that the whole junction is chiral in a specific way. This formalism also allows the prediction of qualitative changes of the spin-polarization upon substitution of a chiral molecule in the junction with its enantiomeric partner. Quantum transport calculations based on density functional theory corroborate all of our predictions and provide further quantitative insight within the single-particle framework.

Unraveling the Interplay between Quantum Transport and Geometrical Conformations in Monocyclic Hydrocarbons' Molecular Junctions.

In the field of molecular electronics, especially in quantum transport experiments, determining the geometrical configurations of a single molecule trapped between two electrodes can be challenging. To address this challenge, we employed a combination of molecular dynamics (MD) simulations and electronic transport calculations based on density functional theory to determine the molecular orientation in our break-junction experiments under ambient conditions. The molecules used in this study are common solvents used in molecular electronics, such as benzene, toluene (aromatic), and cyclohexane (aliphatic). Furthermore, we introduced a novel criterion based on the normal vector of the surface formed by the cavity of these ring-shaped monocyclic hydrocarbon molecules to clearly define the orientation of the molecules with respect to the electrodes. By comparing the results obtained through MD simulations and density functional theory with experimental data, we observed that both are in good agreement. This agreement helps us to uncover the different geometrical configurations that these molecules adopt in break-junction experiments. This approach can significantly improve our understanding of molecular electronics, especially when using more complex cyclic hydrocarbons.

Pediatric lung function testing during a pandemic: An international perspective.

The COVID pandemic has passed its first peak for now in many countries while some are still on the rise, with some facing a second wave of cases. Precautions and infection control measures for both pediatric and adult pulmonary function testing (PFT) have been a topic of debate during the pandemic. Many centers had to close their PFT laboratories during the initial periods of the pandemic and are reopening as the numbers of new cases are decreasing. This review aims to summarize different practices of PFT laboratory management in different countries, including patient appointments, personal protective equipment, testing room requirements and telemedicine during and immediately following the COVID pandemic.

Timing of oral feeding changes in premature infants who underwent osteopathic manipulative treatment.

BACKGROUND: The delayed transition from gavage-to-nipple feeding is one of the most significant factors that may prolong hospital length of stay (LOS). Osteopathic manipulative treatment (OMT) has been demonstrated to be effective regarding LOS reduction, but no investigations have documented its clinical validity for attaining oral feeding. OBJECTIVES: To assess OMT utility regarding the timing of oral feeding in healthy preterm infants. DESIGN: Preliminary propensity score-matched retrospective cohort study. SETTING: Data were extrapolated from the neonatal intensive care unit (NICU) of Del Ponte Hospital in Varese, Italy, during the period between March 2012 and December 2013. INTERVENTIONS: Two propensity score-matched groups of healthy preterm infants aged 28+0 to 33+6 were compared, observing those supported with OMT until hospital discharge and control subjects. MAIN OUTCOME MEASURES: Days from birth to the attainment of oral feeding was the primary endpoint. Body weight, body length, head circumference and LOS were considered as secondary endpoints. RESULTS: Seventy premature infants were included in the study as the control group (n = 35; body weight (BW) = 1457.9 ± 316.2 g; gestational age (GA) = 31.5 ± 1.73 wk) and the osteopathic group (n = 35; BW = 1509.6 ± 250.8 g; GA = 31.8 ± 1.64 wk). The two groups had analogous characteristics at study entry. In this cohort, we observed a significant reduction in TOF (-5.00 days; p = 0.042) in the osteopathic group with a greater effect in very low birth weight infants. CONCLUSIONS: These data demonstrate the utility and potential efficacy of OMT for the attainment of oral feeding. Further adequately powered clinical trials are recommended.

Influence of Relativistic Effects on the Contact Formation of Transition Metals.

Our analysis of the contact formation processes undergone by Au, Ag, and Cu nanojunctions reveals that the distance at which the two closest atoms on a pair of opposing electrodes jump into contact is, on average, 2 times longer for Au than either Ag or Cu. This suggests the existence of a longer-range interaction between those two atoms in the case of Au, a result of the significant relativistic energy contributions to the electronic structure of this metal, as confirmed by ab initio calculations. Once in the contact regime, the differences between Au, Ag, and Cu are subtle, and the conductance of single-atom contacts for metals of similar chemical valence is mostly determined by geometry and coordination.

Iginio Tansini revisited.

The origin of the muscolocutaneous latissimus dorsi flap dates back to 1906 when Igino Tansini, an Italian surgeon, described a procedure to reconstruct the mastectomy defect. After a detailed study of Tansini's original description and drawings, new insights about the pedicle of its compound flap have been found, showing that it has the same pedicle of the scapular flap. In the end, Tansini's flap should be more correctly considered as a compound musculocutaneous scapular flap.

Antibiotic allergy.

Antibiotics are commonly injected during the perioperative period and are responsible of 15 percent of the anaphylactic reactions. Anaphylaxis triggered by antibiotics primarily involves penicillin and cephalosporin. The management of patients with histories of allergic reactions to antibiotics is a common situation in clinical practice. The confirmation or invalidation of the allergic nature of the reported reaction is not based on in vitro tests, but on a rigorous allergological work-up based on detailed analysis of clinical history, skin tests and drug provocation test. Considering a possible cross-reactivity between penicillins, once an immediate penicillin allergy has been diagnosed, skin testing with the alternative molecule (cephalosporin, carbapenem, aztreonam) is mandatory and, if negative, the relevant drug should be given in an appropriate setting at increasing doses.

Lycopene and cardiovascular diseases: an update.

Cardiovascular disease (CVD) is the leading cause of death in Western societies and accounts for up to a third of all deaths worldwide. In comparison to the Northern European or other Western countries, the Mediterranean area has lower rates of mortality from cardiovascular diseases and cancer, and this is attributed, at least in part, to the so-called Mediterranean diet, which is rich in plantderived bioactive phytochemicals. Identification of the active constituents of the Mediterranean diet is therefore crucial to the formulation of appropriate dietary guidelines. Lycopene is a natural carotenoid found in tomato, an essential component of the Mediterranean diet, which, although belonging to the carotenoid family, does not have pro-vitamin A activity but many other biochemical functions as an antioxidant scavenger, hypolipaemic agent, inhibitor of pro-inflammatory and pro-thrombotic factors, thus potentially of benefit in CVD. In particular, the review intends to conduct a systematic analysis of the literature (epidemiological studies and interventional trials) in order to critically evaluate the association between lycopene (or tomato products) supplementation and cardiovascular diseases and/or cardiovascular disease risk factors progression, and to prepare provision of evidence-based guidelines for patients and clinicians. Several reports have appeared in support of the role of lycopene in the prevention of CVD, mostly based on epidemiological studies showing a dose-response relationship between lycopene and CVD. A less clear and more complex picture emerges from the interventional trials, where several works have reported conflicting results. Although many aspects of lycopene in vivo metabolism, functions and clinical indications remain to be clarified, supplementation of low doses of lycopene has been already suggested as a preventive measure for contrasting and ameliorating many aspects of CVD.

Sildenafil as “first line therapy” in pulmonary persistent hypertension of the newborn?

Despite the recent advances, the clinical approach to persistent pulmonary hypertension of the newborn (PPHN) still represents an important challenge for neonatologists. The care of newborns with PPHN requires meticulous therapeutic and ventilation strategies including, besides the stabilization of the newborn, the use of nitric oxide and high-frequency ventilation. However, not all the neonates with PPHH are responsive to this clinical approach. Recent studies have proposed the use of sildenafil, a phosphodiesterase 5 inhibitor, in refractory forms of PPHN. The aim of this study is to review the cases and the clinical approach of PPHN in the Neonatal Intensive Care Unit of Meyer Children Hospital in the year 2009 and to discuss the possible role of sildenafil in the management of PPHN.

Respiratory impedance and bronchodilator response in healthy Italian preschool children.

OBJECTIVE: To define normal values for respiratory resistance (R(rs)) and reactance (X(rs)) and bronchodilator response (BDR) in a population of healthy Italian preschool children using a commercially available forced oscillation device. METHODS: R(rs) and X(rs) were measured in kindergartens in Viterbo, Italy. Regression analysis was performed taking into account height, weight, age, gender, and reference equations calculated. The coefficient of repeatability (CR) between two tests performed 15 min apart was calculated in a subset of children. BDR was assessed by repeating the measurements 15 min after the administration of 200 µg of inhaled salbutamol and calculated as an absolute change in R(rs) and X(rs) at 8 Hz, as a percent change in baseline, and as a change in Z-score calculated from the reference equations. RESULTS: Lung function was attempted in 175 healthy children and successful in 163 (81 male, median age 4.8, range 2.9-6.1 years). R(rs) and X(rs) at 6, 8, and 10 Hz were related to height but not other variables. The CR was 1.53 hPa s L(-1) for R(rs8) and 0.91 hPa s L(-1) for X(rs8). The 5th percentile for absolute R(rs8) BDR was -3.16 hPa s L(-1), whereas the 95th percentile for absolute X(rs8) BDR was 2.25 hPa s L(-1). These cut-off values corresponded to a change in the Z-score of -1.88 and 2.48, respectively. CONCLUSIONS: We have established reference equations for R(rs) and X(rs) in healthy Italian preschool children using forced oscillations. We recommend a change in Z-score of -1.88 for R(rs8) and 2.48 for X(rs8) as cut-off values for a positive BDR.

Reference ranges for interrupter resistance technique: the Asthma UK Initiative.

Measuring interrupter resistance (R(int)) is an increasingly popular lung function technique and especially suitable for preschool children because it is simple, quick and requires only passive cooperation. A European Respiratory Society (ERS)/American Thoracic Society (ATS) Task Force recently published empirical recommendations related to procedures, limitations and interpretation of the technique. However, for valid interpretation, high-quality reference equations are required and these have been lacking. The aim of the present study was to collate R(int) data from healthy children in order to produce more robust reference equations. A further aim was to examine the influence of methodological differences on predicted R(int) values. R(int) data from healthy children were collected from published and unpublished sources. Reference equations for expiratory and inspiratory R(int) were developed using the LMS (lambda, mu, sigma) method. Data from 1,090 children (51% males) aged 3-13 yrs were collated to construct sex-specific reference equations for expiratory R(int) and data from 629 children (51% males) were collated for inspiratory R(int). Height was the best independent predictor of both expiratory and inspiratory R(int). Differences between centres were clinically irrelevant, and differences between ethnic groups could not be examined. The availability of a large and generalisable sample and the use of modern statistical techniques enabled the development of more appropriate reference equations for R(int) in young children.

Allergen specific nasal challenge to latex in children with latex allergy: clinical and immunological evaluation.

There are no data concerning the significance of allergen specific nasal challenge to latex (ASNCL) in the pediatric population and the effect of mometasone furoate nasal spray (MFNS), topic corticosteroid exerting a potent anti-inflammatory activity in children with latex allergic rhinitis. The aims of this study are: to investigate the clinical and immune pathological effects of ASNCL in children with latex allergy; to study the effects of MFNS pre-medication on the clinical and immune pathological effects of ASNCL in children with latex allergy. Thirteen children: 6 male and 7 female, mean (SD) age 9.6 (2.9) years, with latex allergy and seven children: 3 male and 4 female, mean (SD) age 9.9 (3.8) years, without latex allergy underwent ASNCL. Nasal symptoms were recorded, nasal lavage fluid was collected to measure tryptase, eosinophil cationic protein (ECP), interleukin-5, interferon-gamma levels, and spirometric test was performed for each patient without or with premedication with MFNS. ASNCL induced a clinical allergic response and increased tryptase levels only in children with latex allergy. No serious adverse events occurred after ASNCL. MFNS premedication reduced both tryptase and ECP levels only in children with latex allergy. ASNCL is a simple, reliable and useful tool to make or confirm the diagnosis of nasal symptoms due to latex; it allows us to study both clinical symptoms and local immunological changes. MFNS premedication before an ASNCL may prevent some immunological responses induced by ASNCL without clinical allergic modifications.

Comparison between pulse oximetry and transthoracic impedance alarm traces during home monitoring.

OBJECTIVE: To compare transthoracic impedance (TTI/ECG) and pulse oximetry alarm traces detected during home monitoring in infants at risk of apnoea, bradycardia and hypoxaemia. STUDY DESIGN: A retrospective evaluation of the monitor downloads of 67 infants who had undergone either TTI/ECG or pulse oximetry home monitoring using a device which can detect both parameters. METHODS: The patients were categorised as: apparent life-threatening events (n = 39), preterm infants (n = 21) and miscellaneous (n = 7). TTI/ECG and pulse oximetry alarm traces were scored as either true or false alarms. Classification criteria were based on visual analysis of the impedance and plethysmographic waveforms captured by the memory monitor every time alarm thresholds were violated. RESULTS: 5242 alarms occurred over 3452 days of monitoring: 4562 (87%) were false and 680 (13%) true. The mean duration of monitoring was 51 days (range 5-220 days). There were 2982 TTI/ECG false alarms (65% of the total) and 1580 pulse oximetry false alarms (35%) (p = 0.0042). Of the 680 true alarms, 507 (74%) were desaturations not attributable to central apnoea and 173 (26%) were true TTI/ECG alarms (p = 0.0013). CONCLUSIONS: Comparison of pulse oximetry and TTI/ECG alarm traces shows that true events were mostly attributable to desaturations, while false alarms were mainly provoked by TTI/ECG. The total number of false alarms is lower than reported in other studies using TTI/ECG only, thus indicating that monitoring using both pulse oximetry and TTI/ECG is suitable for home use. When the combination of both techniques is not feasible or not required, we recommend the use of motion resistant pulse oximetry alone.

Diagnostic value of three different latex extracts.

The diagnosis of latex allergy is made on clinical history, but a confirmatory skin prick test (SPT) or a serological assay based on a commercial latex extract is always recommendable. Different raw materials can be used in the preparation of commercial latex extracts. Such extracts can consequently show both different qualitative profiles and a different diagnostic potential. Therefore, the selection of a proper latex extract is essential for in vitro and in vivo diagnosis of latex allergy. In the present study three different latex extracts, prepared from different raw materials (ammoniated -AL-, serum -SL-, or rubber particles -RPE- latex), are compared by in vitro techniques using sera from twenty patients with latex allergy. SDS-PAGE technique was used to compare the antigenic profile of the three latex extracts. Subsequently, their allergenic profiles were evaluated by immunoblotting technique using the individual sera from the twenty latex allergic patients. The diagnostic potential of the three latex extracts was also evaluated using direct Radio-Allergo-Sorbent Test (RAST) as well as skin prick tests (SPTs). In order to establish the more appropriate latex extract in a perspective of in vivo diagnosis of latex sensitization, the same latex extracts were subsequently compared by an in vivo SPT involving ten of the above subjects. The SDS-PAGE profiles of the three latex extracts examined were quite different. SL extract showed numerous bands comprised between 10-100 kDa. RPE extract was characterized by two intense bands at 14 and 20 kDa while AL extract showed the poorer antigenic composition. Analogously, immunoblotting analysis evidenced a different profile in relation to both different patients and extracts. For only two out of the twenty sera, direct RAST results showed a same positive class in relation to the different latex extracts used. SPT with SL extract showed, in respect to the other extracts (AL, RPE), a significantly higher wheal. This study showed that SL extract is able to express the best in vitro and in vivo diagnostic potential. Thus, its use should be preferred for the diagnosis of patients affected by latex allergy.

Nitric oxide (NO) inhibits prostaglandin E2 9-ketoreductase (9-KPR) activity in human fetal membranes.

Nitric oxide (NO) synthesized by fetal membranes may act either directly inhibiting myometrium contractility or indirectly interacting with tocolytic agents as prostaglandins (PGs). Here we examined if NO could modulate prostaglandin E(2) 9-ketoreductase (9-KPR) activity in human fetal membranes (HFM). 9-KPR is the enzyme that converts PGE(2) into PGF(2alpha), the main PGs known to induce uterine contractility at term. Chorioamnion explants obtained from elective caesareans were incubated with aminoguanidine (AG), an iNOS inhibitor, or NOC-18, a NO donor. NOC-18 (2mM) increased PGE(2) production and diminished PGF(2alpha) synthesis in HFM. AG presented the opposite effect. When we evaluated the activity of 9-KPR by the conversion of [(3)H]-PGE(2) into [(3)H]-PGF(2alpha) and 13,14-dihidro-15-keto prostaglandin F(2alpha) (the PGF(2alpha) metabolite), we found that NOC-18 inhibited 9-KPR activity. Interestingly, AG did not elicit any effect on 9-KPR but l-NAME, a non-selective NOS inhibitor, significantly increased its activity. Our data suggests that exogenous NO inhibits 9-KPR activity in HFM, thus modulating the synthesis of important labor mediators as PGF(2alpha).

Mould/dampness exposure at home is associated with respiratory disorders in Italian children and adolescents: the SIDRIA-2 Study.

AIMS: To report on the relation between home mould and/or dampness exposure and respiratory disorders in a large sample of children and adolescents in Italy, accounting for age at time of exposure. METHODS: 20,016 children (mean age 7 years) and 13,266 adolescents (mean age 13 years) completed questionnaires on indoor exposures and respiratory symptoms/diseases. Statistical analyses were adjusted for sex, age, questionnaire's compiler, area of residence, season of interview, parental educational status, family history of asthma, rhinitis, eczema, chronic obstructive pulmonary disease, presence of gas water heaters, passive smoking, pets, and active smoking (only for adolescents). Population attributable risk % (PAR) was also computed. RESULTS: Asthma was more strongly related to only early than to only current exposure, both in children (OR 1.80, 95% CI 1.41 to 2.30) and adolescents (OR 1.89, 95% CI 1.38 to 2.59). The same result was found for rhino-conjunctivitis (OR 1.46, 95% CI 1.17 to 1.82), in children, and for wheeze among adolescents (OR 1.56, 95% CI 1.15 to 2.11). In children, wheeze (OR 1.98, 95% CI 1.47 to 2.66) and eczema (OR 1.44, 95% CI 1.09 to 1.91) were more strongly related to mould/dampness when exposed both early and currently; the same occurred in adolescents for rhino-conjunctivitis (1.78, 95% CI 1.30 to 2.45). Although persistent cough/phlegm was significantly related to mould/dampness exposure in children, regardless of exposure timing, no significant association between mould/dampness exposure and eczema or cough/phlegm was found among adolescents. PAR estimates were higher for only early than only current exposures. Avoiding early only exposure would abate wheeze by 6%, asthma or cough/phlegm by 7%, rhino-conjunctivitis in children by 4%, and in adolescents, asthma by 6%, and wheeze by 4%. CONCLUSIONS: Respiratory disorders such as wheeze and asthma can often be explained by exposure to home mould/dampness, especially early in life. The association seems more evident in children than in adolescents. These findings may suggest the need for environmental prevention strategies.

Cross-reactivity between IgE-binding proteins from Anisakis simplex and Dermatophagoides pteronyssinus.

An association was found between Anisakis simplex (As) and Dermatophagoides pteronyssinus (Dp) sensitization. One recent study shows a cross-reactivity between As and Dp and tropomyosin (tr)is suspected as being one of the proteins responsible of this cross-reaction. The aim of our study was: 1) to confirm the cross-reactivity between Dp and As; 2) to determine the importance of tr in this cross reaction. SDS-PAGE analysis of Dp and As (metabolic and somatic) extracts was carried out. Then an IgE immunoblotting test using serum from a patient who had specific IgE only to Dp and As and immunoblotting inhibition experiments using Dp extract and tr as inhibitors were performed. We found that patients serum reacted: 1) against larval As antigens with a molecular weight (mw) of 25 kilodalton (kD) and a mw > than 100 kD, 2) against various metabolic As antigens with a mw > than 100 kD, a mw ranging approximately from 35 to 50 kD, and a mw around 20 kD, and 3) against Dp proteins with mw between 35 and 55 kD. Preincubation of patient's serum with Dp extract caused the disappearance of reactivity against antigens with a mw > than 100 kD in both larval and metabolic As extracts and against proteins with mw ranging approximately from 35 to 50 kD in the metabolic As extract. Preincubation of patients serum with As extract caused the disappearance of reactivity against antigens with mw between 35 and 55 kD in the Dp extract. Pre-incubation of patients serum with tr did not induce any change in the immunoblotting profile. The results show that 1) cross-reactive components between Dp and As are some proteins with a mw ranging approximately from 35 to 50 kD and with a mw > than 100 kD, and 2) tr is not involved in cross-reactivity between As and Dp.

[Factors associated with postoperative mortality following gastric adenocarcinoma surgery at the Edgardo Rebagliati Martins Hospital]. / Factores asociados a la mortalidad postoperatoria luego de cirugia por adenocarcinoma gastrico en el Hospital Edgardo Rebagliati Martins.

OBJECTIVES: This study is a retrospective, descriptive and observational evaluation aimed at defining the factors associated with postoperative mortality due to gastric adenocarcinoma and evaluating postoperative morbidity at the Edgardo Rebagliati Martins Hospital. METHODS: The study included 282 patients, which had undergone surgery between January 1, 1996 and December 31, 1999 and the evaluation involved filiation, background, tumor location, Bormann and Early Cancer classifications, histological classification, number of resected lymphatic nodes, extragastric compromise, type of surgery and reconstruction, TNM classification, clinical stage and medical and surgical complications. RESULTS: Patients were divided in two groups: Survivors (n=251) and deceased (n=31) evidencing 31.56% morbidity and 10.99% mortality. The factors associated with mortality were: age, hypertension (AHT), cardiopathy, tumor location in the stomach, extragastric compromise of the liver, T3 and T4 tumors, N1, distant metastases, clinical stage IV, pneumonia and other surgical complications. CONCLUSIONS: These results lead us to conclude that proper preoperative staging of the disease is necessary and so is special care with patients suffering of hypertension, diabetes and cardiopathy.Finally, we consider it pertinent to bear in mind the postoperative complications, for proper management of them.

Atopy and serum eosinophil cationic protein in 110 white children with vernal keratoconjunctivitis: differences between tarsal and limbal forms.

BACKGROUND: A predominance of Th2 response has been suggested in vernal keratoconjunctivitis (VKC), and a high prevalence of IgE-sensitized (IgE-S) patients has been reported (positive skin prick test or serum-specific-IgE). Palpebral and bulbar VKC are considered to be expressions of the same disease and only occasional racial and histopathological differences are described between the two forms. Tear levels of eosinophil cationic proteins have been correlated with the severity of ocular symptoms; however, there is no published study that demonstrates the presence of serum markers of disease activity. OBJECTIVE: This study was performed to evaluate the prevalence of IgE-sensitization in palpebral, bulbar and mixed VKC and to determine possible useful markers of disease activity in peripheral circulation. METHODS: A total of 110 white VKC patients (mean age 8.3 years, range 3.2-18 years) were evaluated for ocular score in the active phase of the disease. Skin prick tests and serum-specific IgE for common allergens, serum-total IgE, peripheral blood eosinophil counts (PBECs) and serum eosinophil cationic protein (s-ECP) were determined. Fifteen age-matched non-IgE-S control children underwent the same determinations. RESULTS: s-ECP, PBECs and s-total IgE were significantly higher in IgE-S than in non-IgE-S VKC patients and in non-IgE-S VKC patients than in controls. A lower prevalence of IgE-S patients was found in bulbar vs. tarsal (P = 0. 050) or mixed forms (P = 0.002). The score of giant papillae was strongly correlated with s-ECP levels (P < 0.001) and with PBECs (P = 0.001). CONCLUSIONS: Our data suggest that an overall eosinophilic response is present in VKC independently of IgE-sensitization; bulbar forms, unlike tarsal and mixed forms, were associated with a low prevalence of IgE-sensitization. Serum ECP was a useful marker of disease activity in tarsal and mixed forms.