Design, Implementation, and Characterization of a Signal Acquisition Chain for SADino: The Precursor of the Italian Low-Frequency Telescope Named the Sardinia Aperture Array Demonstrator (SAAD)

Low-frequency aperture arrays represent sensitive instruments to detect signals from radio astronomic sources situated in the universe. In Italy, the Sardinia Aperture Array Demonstrator (SAAD) consists of an ongoing project of the Italian National Institute for Astrophysics (INAF) aimed to install an aperture array constituted of 128 dual-polarized Vivaldi antennas at the Sardinia Radio Telescope (SRT) site. The originally envisaged 128 elements of SAAD were re-scoped to the 16 elements of its precursor named SADino, with the aim to quickly test the system with a digital beam-former based on the Italian Tile Processing Module (iTPM) digital back-end. A preliminary measurements campaign of radio frequency interference (RFI) was performed to survey the less contaminated spectral region. The results of these measurements permitted the establishment of the technical requirements for receiving a chain for the SADino telescope. In this paper, the design, implementation, and characterization of this signal acquisition chain are proposed. The operative frequency window of SAAD and its precursor, SADino, sweeps from 260 MHz to 420 MHz, which appears very attractive for radio astronomy applications and radar observation in space and surveillance awareness (SSA) activities.

Precessing jet nozzle connecting to a spinning black hole in M87

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole1-4. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from general relativity5. With a baseline of 17 years of observations, there was a shift in the jet's transverse position, possibly arising from an 8- to 10-year quasi-periodicity3. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years for the variation in the position angle of the jet. We infer that we are seeing a spinning black hole that induces the Lense-Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.

Microwave Spectroscopy Investigation of Carasau Bread Doughs: Effects of Composition up to 8.5 GHz

Carasau bread is a flat bread, typical of Sardinia (Italy). The market of this food product has a large growth potential, and its industry is experiencing a revolution, characterized by digitalization and automation. To monitor the quality of this food product at different manufacturing stages, microwave sensors and devices could be a cost-effective solution. In this framework, knowledge of the microwave response of Carasau dough is required. Thus far, the analysis of the microwave response of Carasau doughs through dielectric spectroscopy has been limited to the dynamics of fermentation. In this work, we aim to perform complex dielectric permittivity measurements up to 8.5 GHz, investigating and modeling the role of water amount, salt and yeast concentrations on the spectra of this food product. A third-order Cole-Cole model was used to interpret the microwave response of the different samples, resulting in a maximum error of 1.58% and 1.60% for the real and imaginary parts of permittivity, respectively. Thermogravimetric analysis was also performed to support the microwave spectroscopy investigation. We found that dielectric properties of Carasau bread doughs strongly depend on the water content. The analysis highlighted that an increase in water quantity tends to increase the bounded water fraction at the expense of the free water fraction. In particular, the free water amount in the dough is not related to the broadening parameter γ2 of the second pole, whereas the bound water weight fraction is more evident in the γ2 and σdc parameters. An increase in electrical conductivity was observed for increasing water content. The microwave spectrum of the real part of the complex permittivity is slightly affected by composition, while large variation in the imaginary part of the complex dielectric permittivity can be identified, especially for frequencies below 4 GHz. The methodology and data proposed and reported in this work can be used to design a microwave sensor for retrieving the composition of Carasau bread doughs through their dielectric signature.

P-IOTA: A Cloud-Based Geographically Distributed Threat Alert System That Leverages P4 and IOTA

The recent widespread novel network technologies for programming data planes are remarkably enhancing the customization of data packet processing. In this direction, the Programming Protocol-independent Packet Processors (P4) is envisioned as a disruptive technology, capable of configuring network devices in a highly customizable way. P4 enables network devices to adapt their behaviors to mitigate malicious attacks (e.g., denial of service). Distributed ledger technologies (DLTs), such as blockchain, allow secure reporting alerts on malicious actions detected across different areas. However, the blockchain suffers from major scalability concerns due to the consensus protocols needed to agree on a global state of the network. To overcome these limitations, new solutions have recently emerged. IOTA is a next-generation distributed ledger engineered to tackle the scalability limits while still providing the same security capabilities such as immutability, traceability, and transparency. This article proposes an architecture that integrates a P4-based data plane software-defined network (SDN) and an IOTA layer employed to notify about networking attacks. Specifically, we propose a fast, secure, and energy-efficient DLT-enabled architecture that combines the IOTA data structure, named Tangle, with the SDN layer to detect and notify about network threats.

Audiological Risk Factors, Referral Rates and Dropouts: 9 Years of Universal Newborn Hearing Screening in North Sardinia

Background: Objectives of the present work were to analyze the prevalence of hearing loss in our population of screened newborns during the first 9 years of the universal newborn hearing screening (UNHS) program at University Hospital Sassari (Italy) (AOU Sassari), to analyze the risk factors involved, and to analyze our effectiveness in terms of referral rates and dropout rates. Methods: Monocentric retrospective study whose target population included all the newborns born or referred to our hospital between 2011 and 2019. Results: From 2011 to 2019, a total of 11,688 babies were enrolled in our screening program. In total, 3.9‱ of wellborn babies and 3.58% of neonatal intensive care unit (NICU) babies had some degree of hearing loss. The most frequently observed risk factors among non-NICU babies were family history of hearing loss (3.34%) and craniofacial anomalies (0.16%), among NICU babies were low birth weight (54.91%) and prematurity (24.33%). In the multivariate analysis, family history of hearing loss (p < 0.001), NICU (p < 0.001), craniofacial anomalies (p < 0.001), low birth weight (<1500 g) (p = 0.04) and HIV (p = 0.03) were confirmed as risk factors. Conclusions: Our data are largely consistent with the literature and most results were expected, one relevant exception being the possible role of NICU as a confounding factor and the limited number of risk factors confirmed in the multivariate analysis.

The mm-to-cm SED of spiral galaxies

The mm-to-cm range of the Spectral Energy Distribution of spiral galaxies remains largely unexplored. Its coverage is required to disentangle the contribution of dust emission, free-free and synchrotron radiation and can provide constraints on dust models, star-formation rates and ISM properties. We present the case for a synergy between NIKA2 observations of nearby spirals and those from planned and current instrumentation at the Sardinia Radio Telescope, and report on a pilot K-band program to search for Anomalous Microwave Emission, an elusive emission component which is presumably related to dust.

Microservice security: a systematic literature review

Microservices is an emerging paradigm for developing distributed systems. With their widespread adoption, more and more work investigated the relation between microservices and security. Alas, the literature on this subject does not form a well-defined corpus: it is spread over many venues and composed of contributions mainly addressing specific scenarios or needs. In this work, we conduct a systematic review of the field, gathering 290 relevant publications-at the time of writing, the largest curated dataset on the topic. We analyse our dataset along two lines: (a) quantitatively, through publication metadata, which allows us to chart publication outlets, communities, approaches, and tackled issues; (b) qualitatively, through 20 research questions used to provide an aggregated overview of the literature and to spot gaps left open. We summarise our analyses in the conclusion in the form of a call for action to address the main open challenges.

Microservice security: a systematic literature review

Microservices is an emerging paradigm for developing distributed systems. With their widespread adoption, more and more work investigated the relation between microservices and security. Alas, the literature on this subject does not form a well-defined corpus: it is spread over many venues and composed of contributions mainly addressing specific scenarios or needs. In this work, we conduct a systematic review of the field, gathering 290 relevant publications-at the time of writing, the largest curated dataset on the topic. We analyse our dataset along two lines: (a) quantitatively, through publication metadata, which allows us to chart publication outlets, communities, approaches, and tackled issues; (b) qualitatively, through 20 research questions used to provide an aggregated overview of the literature and to spot gaps left open. We summarise our analyses in the conclusion in the form of a call for action to address the main open challenges.

A prospective pilot study on the effects of endoscopic sinus surgery on upper and lower airway performance

Objective

Methods

Results

Conclusions

Exploring children breakfast habits using Zoom8-questionnaire: Results from the I-MOVE Study

Background

Scientific evidence widely argues that consuming breakfast daily is considered a good habit which positively affects health and academic performance, especially in children. In order to be adequate, according to national requirements, breakfast should include a portion of milk or yogurt and one grain based product, providing about 15-20% of the daily recommended energy intake. The aim of this study was to analyse breakfast habits in a convenience sample of primary school children inside the Imola Active Breaks Study.

Methods

A cross-sectional study was conducted in a sample of children, aged 6-10, recruited in a primary school of Imola (Emilia Romagna region, Italy). The Zoom8 self-reported questionnaire, which investigates dietary habits and lifestyle aspects were administered to parents to explore the children's breakfast habits.

Results

A total of 155 children were recruited in November 2019. Breakfast was consumed daily by 117 children (75%), 4-6 times/week by 12 (7%), 2-4 times/week by 4 (3%), and 22 (14%) did not answer. Concerning dairy products' consumption: 50 (32%) children reported milk or yogurt, 47 (30%) milk, 6 (4%) yogurt, 9 (6%) neither of them and 43 (28%) gave no answer. Mostly all the children consumed at least one of these products: biscuits, cakes, croissants, industrial snacks or cereals. 108 children (70%) recognised that the consumption of a dairy and a carbohydrate product represent an adequate breakfast.

Conclusions

The findings suggested that the majority of children consumed one grain based product for breakfast, but most of them were high in sugar and fat content (industrial snacks and croissants). Still not every child had breakfast daily nor had a portion of a dairy product. Measurements should be taken to avoid skipping breakfast and to promote a more balanced breakfast. It would be advisable to analyse in detail the frequency of consumption of each food group and their energy intake.

Key messages

Breakfast consumption positively affects children’s health and academic performance. Health Promotion should stimulate daily consumption of breakfast and improve its quality and energy intake.

Association between parents’ education level and KIDMED index: a cross-sectional study

Background

Mediterranean diet (MD) is considered a healthy dietary model with several beneficial effects.

A strict adherence to the MD in children, coupled with daily exercise, can prevent obesity and significantly reduce the risk of correlated chronic diseases, such metabolic syndrome. The aim of this study is to evaluate the association between parents' educational level and compliance to the MD in a convenience sample of Italian children.

Methods

We conducted a cross-sectional study among 428 children aged 6-11 recruited in a primary school of Calderara di Reno (Italy) between May and June of 2017. Children's and parents' information were collected at baseline (i.e. age, BMI, occupation, educational level). A weekly food diary was administered to evaluate the participant's dietary habits. The degree of adherence to MD was derived from these diaries using the KIDMED index developed in 2003 by Serra-Majem et al. We used multiple linear regression models, adjusted for age and gender, to investigate how parents' educational level affected children's KIDMED index.

Results

Adherence to the MD was high, medium and poor in, respectively, 4%, 60% and 36% of children. Higher prevalence of overweight and obesity was observed among those with lower adherence to the MD. The linear regression model shows that fathers' educational level is not associated to children's KIDMED index variation. On the other hand, a higher mothers' educational level is linked to an increased weekly KIDMED index (p = 0.012) as well as an increased weekend KIDMED index (p = 0.048).

Conclusions

Mothers' education level is associated with increased adherence to MD, both weekly and weekend. The greater difference has been observed during weekend, when children of highly educated mothers score higher at KIDMED index.

Key messages

Mothers’ educational level plays an important role in children’s eating habits, with higher educational level associated with a better adherence to the MD. It is critical to implement parents' toolkit to promote healthy dietary patterns and adherence to MD in order to correct these social differences.

Audiovestibular symptoms and sequelae in COVID-19 patients

BACKGROUND

since the beginning of COVID-19 outbreak a growing number of symptoms and deficits associated with the new pathology have emerged, among them cochlear damage in otherwise asymptomatic COVID-19 patients has been described.

OBJECTIVE

to investigate general and audiovestibular symptoms and sequelae in healed patients, and to seek for any sign of residual or permanent hearing or vestibular loss.

METHODS

we reviewed the data coming from 48 Covid-19 patients whose nasopharyngeal swabs have turned negative, all employed at our facility, that opted in for a free screening of audiovestibular symptoms offered by our hospital after the aforementioned report was published. The screening included a tonal pure tone audiometry, a vHIT and SHIMP test, as well as a survey including known symptoms and audiovestibular symptoms.

RESULTS

general symptoms as reported by our patients largely reflect what reported by others in the literature. 4 (8.3%) patients reported hearing loss, 2 (4.2%) tinnitus, 4 dizziness (8.3%), 1 spinning vertigo (2%), 1 dynamic imbalance (2%), 3 static imbalance (6.3%). Most audiovestibular symptoms have regressed. Thresholds at pure tone audiometry and vHIT gain were within normality range in all post-Covid-19 patients.

CONCLUSIONS

even if some patients suffer from audiovestibular symptoms, these are mostly transitory and there is no clear evidence of clinically relevant persistent cochlear or vestibular damage after recovery.

Relationship between calcium metabolism and benign paroxysmal positional vertigo in north Sardinia population

BACKGROUND

Benign paroxysmal positional vertigo (BPPV) has a reported recurrence ranging from 26.8 to 50%. Osteoporosis and Vitamin D deficiency seems to have an impact on recurrence of BPPV.

OBJECTIVE

to evaluate the impact of osteoporosis and Vitamin D deficiency on recurrence of BPPV.

METHODS

73 consecutive patients were divided in two groups according to the presence (group 1) or absence (group 0) of a recurrent episode. BMD, femoral and lumbar T-scores and Vitamin D levels were recorded. Statistical analysis was performed to investigate correlations.

RESULTS

patients in group 1 had statistically significant lower values of both femoral (-1,62±1,06 vs. -0,53±1,51; p = 0,001), lumbar T-score (-2,10±1,19 vs -0, 53±1.51, p = 0.001) and Vitamin D (19.53±15.33). The values of femoral T-score and Vitamin D could be combined in a model able to properly classify 65.8% of the cases (p = 0.002) as isolated or recurrent BPPV, with high accuracy (AUC 0.710 [0.590 -0.830]).

CONCLUSION

present data show a probable correlation between osteoporosis and Vitamin D with recurrent BPPV.

Does the involvement of first-year residents have a negative impact on the performance of a newborn hearing screening program?

OBJECTIVES

We aimed to evaluate the efficiency of our hearing screening program, prior to hospital discharge, together with the consistency of our teamwork including first year residents by assessing a learning curve for the operators involved.

METHODS

We evaluated all the data collected during the first stage of the screening program of all non-NICU neonates from March 2009 to July 2013, analyzing by means of a linear regression model, the monthly referral rate for the whole period of activity of each group of residents.

RESULTS

performances of each group of screeners were statistically different (chi square test p < 0.005). The nptrend test showed that group 2 (p = 0.01) and group 4 (p = 0.01) reached a statistical significance in higher and lower referral rates respectively. No statistical differences were found in other groups (Group 1 p = 0.161; Group 3 p = 0.853).

CONCLUSION

Despite a statistically significant difference in the performances between the groups of residents, the referral rates for each group (range 6.18%-9.29%) and the overall referral rate for the whole period (7.84%) agree with the values commonly reported for TEOAEs in the literature. It means that our screening program is reasonably effective despite a yearly turnover of operators.

Olfactory and gustatory function impairment in COVID-19 patients: Italian objective multicenter-study

BACKGROUND

Objective data on chemosensitive disorders during COVID-19 are lacking in the Literature.

METHODS

Multicenter cohort study that involved four Italian hospitals. Three hundred and forty-five COVID-19 patients underwent objective chemosensitive evaluation.

RESULTS

Chemosensitive disorders self-reported by 256 patients (74.2%) but the 30.1% of the 89 patients who did not report dysfunctions proved objectively hyposmic. Twenty-five percentage of patients were seen serious long-lasting complaints. All asymptomatic patients had a slight lowering of the olfactory threshold. No significant correlations were found between the presence and severity of chemosensitive disorders and the severity of the clinical course. On the contrary, there is a significant correlation between the duration of the olfactory and gustatory symptoms and the development of severe COVID-19.

CONCLUSIONS

Patients under-report the frequency of chemosensitive disorders. Contrary to recent reports, such objective testing refutes the proposal that the presence of olfactory and gustatory dysfunction may predict a milder course, but instead suggests that those with more severe disease neglect such symptoms in the setting of severe respiratory disease.

Medical-surgical management and clinical outcome in cervical abscesses

INTRODUCTION

This study aims at defining through a retrospective evaluation, the clinical parameters affecting the clinical course and consequently the management of patients presenting with cervicofacial abscesses.

METHODOLOGY

A total of 394 patients diagnosed with abscess at the University of Sassari Otorhinolaryngology Division between 2009 and 2017 were included; among these, eleven patients were diagnosed with necrotizing fasciitis. Personal and clinical parameters including the LRINEC score and the medical and/or surgical treatment used were analyzed for each patient. The most frequently affected site was the peritonsillar space (76.9%), followed by the parapharyngeal space.

RESULTS

Mean age was 41(±17) years, the male population was slightly overrepresented (68%). An average of 6 (±7) days of hospitalization duration was recorded. The mortality rate was confirmed to be relatively low (1/349 patients) and was reported only in one patient diagnosed with necrotizing fasciitis (1/11).

CONCLUSION

Diagnosis, correct clinical definition and early medical-surgical treatment of neck abscesses were crucial to reduce complications; LRNEC score, C-reactive protein, glycemia and creatininemia proved to be reliable prognostic indicators of difficult patient management and risk of complications.

Influence of metals on rhinosinusal polyposis in Sardinian population (Italy)

Metals have strong toxic effects in humans and can act as immunoregulatory factors. The purpose of our study was to determine whether the concentrations of metals are associated with the clinical course of nasal polyposis (NP). We measured the concentrations of 10 metals and non-metal (Zn, Mn, Se, Fe, Cr, Ni, Pb, Al, Cd, and Cu) in 58 patients with NP, and 29 controls with a healthy nasal mucosa. We used electron microscopy to compare the ultrastructural features of the nasal mucosa between NP patients and healthy controls. Concentrations of metals in nasal polyps and healthy mucosa were determined by mass spectrometry. Transmission electron microscopic (TEM) and scanning electron microscopic (SEM) images of the nasal mucosa were obtained. The mean tissue concentrations of all 10 metals and non-metal were significantly lower in NP patients than in healthy controls (P < 0.05).TEM and SEM revealed changes in the mucosal ultrastructure in NP with progressive fibrosis, devascularisation, and inflammation. Tissue concentrations of metals were lower in NP patients than in healthy controls, and this was particularly evident in massive polyposis.

A comparative reference study for the validation of HLA-matching algorithms in the search for allogeneic hematopoietic stem cell donors and cord blood units

The accuracy of human leukocyte antigen (HLA)‐matching algorithms is a prerequisite for the correct and efficient identification of optimal unrelated donors for patients requiring hematopoietic stem cell transplantation. The goal of this World Marrow Donor Association study was to validate established matching algorithms from different international donor registries by challenging them with simulated input data and subsequently comparing the output. This experiment addressed three specific aspects of HLA matching using different data sets for tasks of increasing complexity. The first two tasks targeted the traditional matching approach identifying discrepancies between patient and donor HLA genotypes by counting antigen and allele differences. Contemporary matching procedures predicting the probability for HLA identity using haplotype frequencies were addressed by the third task. In each task, the identified disparities between the results of the participating computer programs were analyzed, classified and quantified. This study led to a deep understanding of the algorithms participating and finally produced virtually identical results. The unresolved discrepancies total to less than 1%, 4% and 2% for the three tasks and are mostly because of individual decisions in the design of the programs. Based on these findings, reference results for the three input data sets were compiled that can be used to validate future matching algorithms and thus improve the quality of the global donor search process.

Efficiency of auricular acupuncture in climacteric symptoms after cancer treatments

OBJECTIVES

This paper aims to highlight the efficiency of auriculotherapy in the treatment of hot flushes, especially in cancer-related menopausal transition.

METHODS

We used systematically collected data from patients in 2014 in a medical oncology practice. The treatment was made according to the guidelines of The Inter-University Diploma and the cartography of the World Health Organization; data on satisfaction were collected orally.

RESULTS

In 2014, 49 patients, among whom 41 had cancer, were treated for hot flushes. Although it is not recommended to treat several symptoms during the same session, we dealt with 1.7 symptoms per session on average. Sixty-nine percent of the patients were satisfied. We lacked data for nine patients, who did not come to the minimal recommended number of treatments (three). Only one patient among those who did not observe any improvement received three treatments.

CONCLUSIONS

Auricular acupuncture is a safe and cheap method to treat hot flushes. It has been effective in numerous and various cases, among which were patients who presented cancer-related menopausal symptoms. It may be applied for a large variety of other symptoms.

Comparison of three different polyvinyl alcohol packs following functional endoscopic Nasal surgery

OBJECTIVES/HYPOTHESIS

To compare the extent of bleeding and patient discomfort during packing removal of three different polyvinyl alcohol (PVA) packs: 1) a standard PVA sponge (s-PVA) (Mondocel Standard 10 cm; Mondomed NV, Hamont-Achel, Belgium); 2) a PVA sponge with oxidized cellulose (oc-PVA) (Merocel Hemox 10 cm; Medtronic Xomed Surgical Products, Jacksonville, FL); and 3) a PVA sponge with polyethylene film (pf-PVA) (Merocel 2000 8 cm; Medtronic Xomed Surgical Products, Jacksonville, FL), after functional endoscopic sinus surgery and inferior turbinoplasty.

STUDY DESIGN

A prospective, randomized, blinded, controlled trial.

METHODS

Ninety consecutive patients were enrolled and randomized to receive in each side one pack in the middle meatus and another pack of the same material in the nasal fossa. The patients were equally divided in three groups of 30 patients each. Group A received the pf-PVA; group B received oc-PVA; and group C received s-PVA. Postoperatively, bleeding after removal of the entire nasal packing was evaluated by an observer, whereas the severity of pain was rated by patients with visual analog scales.

RESULTS

Our study evaluated three nasal packing materials, demonstrating that the pf-PVA is less painful than the others but with intermediate bleeding ratio. However, the oc-PVA has an intermediate pain score but minimum bleeding. The s-PVA showed the worst pain and bleeding results.

CONCLUSIONS

Considering that removal of the second pack (middle meatus) is more painful than the first (nasal fossa), our results suggest that a pf-PVA can be placed in the middle meatus and a oc-PVA in the nasal fossa in order to reduce patient's discomfort in terms of pain and bleeding.

LEVEL OF EVIDENCE

1b.

Is oral chemotherapy prescription safe for patients? A cross-sectional survey

BACKGROUND

Oral chemotherapies are increasingly prescribed. Yet wide variations in prescription practices and in monitoring of toxicity have been underlined despite existing guidelines. There is little recent information available as regard to these practices. We aimed to obtain exhaustive information on oral chemotherapy prescription practices and safety monitoring in French hospitals.

METHODS

A cross-sectional multicentre survey was carried out to collect information on drug prescription, administration and surveillance: prescribing practices, coordination and monitoring of adherence, safety monitoring and side-effects occurrence prevention. Participants were a large sample of the French oncologists prescribing oral chemotherapy (20%).

RESULTS

One hundred and fifty-seven oncologists from 112 hospitals (public, comprehensive cancer centres and private) replied (23.7% of cancer hospitals). The majority (56.1%) of the prescriptions were hand-written on a blank sheet. Eighty-four physicians (53.5%) included dose information and 36 (23%) declared having no monitoring procedures for adherence. Only 84 responders (54%) provided education material at first prescription of oral chemotherapy in way to limit avoidable side-effects. Sixty-one (39%) responders stated that they recalled at least one serious adverse event in the previous year declared in their centre.

CONCLUSIONS

In this 2012 study, the majority of prescribers followed no standards in prescription writing, safety monitoring and toxicity prevention. The implementation of the international recommendations for oral chemotherapy administration should be considered as a top priority-for both prescribers and health authorities-as regards to the dynamic of development of these molecules and their potential side-effects.

Light quality regulates expression of chloroplast genes and assembly of photosynthetic membrane complexes

The concentrations of photosystem I (PSI) and photosystem II (PSII) reaction centers and the level of chloroplast reaction center gene transcripts were determined in pea plants grown under different light-quality regimes. In plants grown in light primarily absorbed by PSI ("red" light), the PSII/PSI reaction center ratio was 2-fold greater than that in plants grown in PSII-sensitizing ("yellow") light. In addition, the ratio of a PSII gene (psbB) transcript to a PSI gene (psaA) transcript was 2.6 times greater in red-grown plants relative to yellow-grown plants. Thus, a differential reaction-center concentration in the thylakoid membrane was accompanied by a differential expression of reaction center genes, suggesting that the synthesis of chloroplast membrane complexes and the assembly of photosystems are regulated by light quality at the transcriptional and/or post-transcriptional level.

Localization of different photosystems in separate regions of chloroplast membranes

The stoichiometric amounts and the photoactivity kinetics of photosystem I (PSI) and of the alpha and beta components of photosystem II (PSII(alpha) and PSII(beta)) were compared in spinach chloroplast membrane (thylakoid) fractions derived from appressed and nonappressed regions. Stroma-exposed thylakoid fractions from the nonappressed regions were isolated by differential centrifugation following a mechanical press treatment of the chloroplasts. Thylakoid vesicles derived mainly from the appressed membranes of grana were isolated by the aqueous polymer two-phase partition method. Stroma-exposed thylakoids were found to have a chlorophyll a/chlorophyll b ratio of 6.0 and a PSII(beta)/PSI reaction center ratio of 0.3. Kinetic analysis of system II photoactivity revealed the absence of PSII(alpha) from stroma-exposed thylakoids. The photoactivity of system I in stroma-exposed thylakoids showed a single kinetic component identical to that of unfractionated chloroplasts, suggesting that PSI does not receive excitation energy from the PSII-chlorophyll ab light-harvesting complex. Thus, stroma-exposed thylakoids are significantly enriched in both PSI and PSII(beta). Inside-out vesicles from the appressed membranes of grana-partition regions had a chlorophyll a/chlorophyll b ratio of 2.0 and a PSII/PSI reaction center ratio of 10.0. The photoactivity of system II showed the membranes of the grana-partition regions to be significantly enriched in PSII(alpha). We conclude that PSII(alpha) is exclusively located in the membranes of the grana partitions while PSII(beta) and PSI are located in stroma-exposed thylakoids. The low PSI reaction center (P700) content of vesicles derived from grana partitions and the kinetic homogeneity of the PSI complex suggest total exclusion of P700 as a functional component in the membrane of the grana-partition region.

Protonophores induce plastoquinol oxidation and quench chloroplast fluorescence: Evidence for a cyclic, proton-conducting pathway in oxygenic photosynthesis

The photosynthetic apparatus converts light into chemical energy by a series of reactions that give rise to a coupled flow of electrons and protons that generate reducing power and ATP, respectively. A key intermediate in these reactions is plastoquinone (PQ), the most abundant electron and proton (hydrogen) carrier in photosynthetic membranes (thylakoids). PQ ultimately transfers electrons to a terminal electron acceptor by way of the Rieske Fe-S center of the cytochrome bf complex. In the absence of a terminal acceptor, electrons accumulate in the PQ pool, which is reduced to plastoquinol (PQH(2)), and also on a specialized PQ, Q(A), which is reduced to an unprotonated semiquinone anion (Q(A) (-)). The accumulation of Q(A) (-) is measured by a rise in fluorescence yield and the accumulation of PQH(2) is measured by absorption difference spectrometry. We have found that in the absence of a terminal electron acceptor, two chemically diverse proton-conducting ionophores (protonophores), 2,6-di-t-butyl-4-(2',2'-dicyanovinyl)phenol (SF 6847) and carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP), induced oxidation of PQH(2) and quenching of chloroplast fluorescence, signifying oxidation of Q(A) (-). The two protonophores produced the same effects even when the only recognized pathway of PQH(2) oxidation by way of the cytochrome bf complex was inhibited by dibromothymoquinone. Two other uncouplers, gramicidin and nigericin, which are not protonophores but facilitate proton movement across membranes by other mechanisms, were ineffective. These findings are consistent with the operation in the oxygen-generating photosystem (photosystem II) of a cyclic, proton-conducting pathway.

Stoichiometry of system I and system II reaction centers and of plastoquinone in different photosynthetic membranes

The concentrations of photochemical centers and of plastoquinone were measured in several kinds of photosynthetic membranes by optical difference spectroscopy. Photosystem I reaction centers were measured from the light-induced absorbance change at 700 nm (oxidation of the primary electron donor, P700). Photosystem II reaction centers were estimated from the light-induced absorbance change at 325 nm (reduction of the primary electron acceptor, Q). Spinach chloroplasts and membrane fractions obtained by French press treatment, mature and developing pea chloroplasts, and blue-green algal membranes were investigated. No loss of primary photochemical activity occurred during fractionation of the chloroplasts. The results indicated a large variability in the ratio of system II to system I reaction centers (from 0.43 to 3.3) in different photosynthetic membranes. Oxygen-evolving plants may change the ratio of their photosystems in response to environmental light conditions. The amount of photoreducible plastoquinone was also measured at 263 nm. In spinach chloroplasts, seven to eight plastoquinone molecules were found per reaction center of system II. Most of the plastoquinone pool was associated with the grana. However, the ratio of chemically determined plastoquinone to chlorophyll was similar in the grana and stroma thylakoids.

Color-flow Doppler sonography in the differential diagnosis and management of amiodarone-induced thyrotoxicosis

BACKGROUND

Amiodarone-induced thyrotoxicosis (AIT) may be caused by excessive thyroidal hormone synthesis and release (type 1) or by a destructive process (type 2). This differentiation is considered essential for therapeutic choice.

PURPOSE

To evaluate the utility of color-flow Doppler sonography (CFDS) in the differential diagnosis and management of AIT.

MATERIAL AND METHODS

The clinical and laboratory data, thyroid sonography (grayscale sonography [GSS], CFDS), thyroid radioiodine uptake (RAIU) and thyroid scintigraphy, treatment, and clinical outcome were retrospectively reviewed in 21 AIT patients. The CFDS pattern of thyroid nodules was separately described from that of the perinodular parenchyma, and AIT was classified as type 1 (increased blood flow) or type 2 (low/no blood flow). Type 1 AIT patients were treated with methimazole (alone or associated with potassium perchlorate), while type 2 patients were treated with prednisone or amiodarone withdrawal alone.

RESULTS

Eleven patients with increased blood flow were considered as type 1, and 10 with low/no blood flow as type 2. Ten of the 11 patients in the first group showed a hypervascular nodular pattern, while one showed a hypervascular parenchymal pattern. Clinical diagnoses were toxic nodular goiter and Graves' disease, respectively. Of the 10 patients with low/no blood flow, six had normal thyroid volume, three small diffuse goiter, and one small multinodular goiter. The clinical outcome showed that 20 of the 21 patients were treatment responsive.

CONCLUSION

CFDS is a useful tool in the differential diagnosis of AIT. This differentiation appeared to be of clinical relevance as regards therapeutic choice. Separate evaluation of parenchymal blood flow from that of nodules may prove beneficial in the diagnosis of underlying thyroid diseases in patients with type 1 AIT.

Therapeutic approach to intrusive luxation injuries in primary dentition. A clinical follow-up study

AIM

This paper reports the results of a fifteen-year study carried out at the Dentoalveolar trauma study Centre of the University of Cagliari Dental Department, on treatment modes utilised for the recovery of periodontal injuries in primary dentition.

MATERIALS AND METHODS

The data referred to dental injuries were collected and recorded according to Andreasen's dental trauma classification: clinical signs and symptoms, patient's age and gender, lesion site and extent of the injury, timeframe between trauma and first dental examination. The authors focused their attention on intrusive luxations in primary dentition, which are a very frequent trauma in children between 1 and 4 years of age. It is extremely difficult to treat such injuries and there is an ongoing discussion about the advisability of extracting the intruded teeth, as opposed to wait and assist their natural repositioning using non-invasive techniques aimed at the maintenance of the eruptive space in the dental arch.

RESULTS

This careful conservative approach allowed the repositioning of about 60% of the 85 intruded teeth examined. It substantially reduced the number and severity of undesirable sequelae, both local (enamel-hypoplasia) and occlusal (tooth retention), so that only in about 25% of the followed-up cases damages of the successor tooth were found in the permanent dentition.

CONCLUSION

The authors conclude their study emphasizing that all those involved in paediatric dentistry must be familiar with periodontal injuries and trained in their treatment, particularly as regards intrusive luxations in primary dentition.

Facteurs du choix de la voie d’abord des hystérectomies pour lésions utérines bénignes (prolapsus et indications obstétricales exclus)

OBJECTIVES

We searched for the factors determining the type of hysterectomy (vaginal, laparoscopy or laparotomy) performed in women with supposedly benign uterine disease.

MATERIAL AND METHOD

We conducted a retrospective study of 101 consecutive hysterectomies performed on voluminous uteruses, prolapsus and obstetrical indications excluded. The following factors likely to have influenced the decisions were examined: patient age, nulliparity, menopausal status, history of laparotomy, uterus weight, narrow vagina, nature of uterus lesions, associated unilateral or bilateral annexectomy, complications.

RESULTS

The frequencies were: vaginal route 58.4% (average uterine weight 249.4 g, range 93-1149 g), laparoscopic preparation 37.6% (average uterine weight 348 g, range 92-818 g), and laparotomy 4% (average uterine weight 586.2 g, range 112-1216 g). Factors determining type of hysterectomy were uterine weight (and therefore volume) (p < 0.05), nulliparity (p < 0.04), narrow vagina probed by compulsory Schuchardt incision (p < 0.02), associated annexectomy (p < 0.01). No other factors were significantly determinant. The vaginal route appears to be highly preferred.

CONCLUSION

Vaginal hysterectomy is clearly the most preferred and practiced. Laparoscopy may be helpful for vaginal hysterectomy and laparotomy is exceptional.

Sequence learning and sequential effects

In a serial reaction time (RT) task with a probabilistic stimulus sequence, the length of the response-to-stimulus interval (RSI) and the sequence complexity was manipulated to investigate the relationship between sequence learning and sequential effects in serial RT tasks. Sequential effects refer to the influence of previous stimulus presentations on the RT to the current stimulus. Sequence learning is stimulus-transition specific and is demonstrated as the difference between practiced and unpracticed sequences within an interpolated random block of trials. There is a clear parallel between sequence learning and specific changes in sequential effect in the short RSI conditions, suggesting that a common mechanism may lie at the basis of sequence learning and automatic facilitation, which is responsible for sequential effects at short RSI. Importantly, the changes in sequential effects accompanying sequence learning are the same as those observed with practice in random serial RT tasks, indicating that the learning process underlying sequence learning is the same as in random tasks.

Factors influencing hospital infection control policies in Italian hospitals

A study was undertaken to determine the resources available in Italian hospitals for the control of nosocomial infections and the factors favouring a successful approach. During January-May 2000 a questionnaire about infection control was sent to the hospital health director of all Italian National Health System hospitals treating acute patients and with more than 3500 admissions in 1999. An active programme was defined as a hospital infection control committee (HICC) meeting at least four times in 1999, the presence of a doctor with infection control responsibilities, a nurse employed in infection control and at least one surveillance activity and one infection control guideline issued or updated in the past two years. There was a response rate of 87.5% (463/529). Almost fifteen percent (69/463) of hospitals had an active programme for Infection Control and 76.2% (353/463) had a HICC. Seventy-one percent (330/463) of the hospitals had a hospital infection control physician and 53% (250/463) had infection control nurses. Fifty-two percent (242/463) reported at least one surveillance activity and 70.8% (328/463) had issued or updated at least one guidance document in the last two years. The presence of regional policies [odds ratio (OR) 8.7], operative groups (OR 4.2), at least one full-time nurse (OR 4.6) and a hospital annual plan which specified infection control (OR 2.1) were statistically associated with an active programme in the multivariate analysis.

Photosystem II damage and repair cycle in the green alga Dunaliella salina: involvement of a chloroplast-localized HSP70

The involvement of HSP70B in the photosystem II damage and repair process in Dunaliella salina was investigated. A full-length cDNA of the D. salina hsp70B gene was cloned and sequenced. Expression patterns of the hsp70B gene were investigated upon shifting a D. salina culture from low-light to high-light growth conditions, designed to significantly accelerate the rate of PSII photodamage. Northern blot analyses and nuclear run-on transcription assays revealed a significant but transient induction of hsp70B gene transcription, followed by a subsequent increase in HSP70B protein synthesis and accumulation. Mild detergent solubilization of photoinhibited thylakoid membranes, in which photodamaged PSII centers had accumulated, followed by native gel electrophoresis revealed the formation of a 320 kDa protein complex that contained, in addition to the HSP70B, the photodamaged but as yet undegraded D1 protein as well as D2 and CP47. Evidence suggested that the 320 kDa complex is a transiently forming PSII repair intermediate. Denaturing solubilization of the 320 kDa PSII repair intermediate by SDS-urea resulted in cross-linking of its polypeptide constituents, yielding a 160 kDa protein complex. The role of the HSP70B in the repair of photodamaged PSII centers, e.g. in stabilizing the disassembled PSII-core complex and in facilitating the D1 degradation and replacement process, is discussed.

Sequential analysis of a Simon task--evidence for an attention-shift account

We investigated the attention-shift hypothesis of the Simon effect by analysing the effect of repeating relevant colour or irrelevant location of the stimulus in four serial reaction time tasks. In Experiment 1 with short response-stimulus intervals (RSI), we assume that there is no time to engage attention at the fixation cross before the onset of a new stimulus. In agreement with the hypothesis, Experiment 1 reveals no Simon effect when the stimulus location is repeated. In Experiment 2 with long RSI, we observe a Simon effect for location repetitions and alternations. In Experiment 3 with long RSI, we hinder the disengagement of attention by displaying the stimulus after response execution. As expected, the Simon effect is reduced for location repetitions. In Experiment 4 with stimuli additionally presented at the fixation cross, responses are faster if the attention shift towards the centrally presented stimulus corresponds with the location of the required response. Additionally, we argue that binding of the stimulus features into an object or event file better explains the so-called blocking of the automatic response-priming route after a noncorresponding trial.

Involvement of zeaxanthin and of the Cbr protein in the repair of photosystem II from photoinhibition in the green alga Dunaliella salina

A light-sensitive and chlorophyll (Chl)-deficient mutant of the green alga Dunaliella salina (dcd1) showed an amplified response to irradiance stress compared to the wild-type. The mutant was yellow-green under low light (100 micromol photons m(-2) s(-1)) and yellow under high irradiance (2000 micromol photons m(-2) s(-1)). The mutant had lower levels of Chl, lower levels of light harvesting complex II, and a smaller Chl antenna size. The mutant contained proportionately greater amounts of photodamaged photosystem (PS) II reaction centers in its thylakoid membranes, suggesting a greater susceptibility to photoinhibition. This phenotype was more pronounced under high than low irradiance. The Cbr protein, known to accumulate when D. salina is exposed to irradiance stress, was pronouncedly expressed in the mutant even under low irradiance. This positively correlated with a higher zeaxanthin content in the mutant. Cbr protein accumulation, xanthophyll cycle de-epoxidation state, and fraction of photodamaged PSII reaction centers in the thylakoid membrane showed a linear dependence on the chloroplast 'photoinhibition index', suggesting a cause-and-effect relationship between photoinhibition, Cbr protein accumulation and xanthophyll cycle de-epoxidation state. These results raised the possibility of zeaxanthin and Cbr involvement in the PSII repair process through photoprotection of the partially disassembled, and presumably vulnerable, PSII core complexes from potentially irreversible photooxidative bleaching.

Hydrogen production. Green algae as a source of energy

Hydrogen gas is thought to be the ideal fuel for a world in which air pollution has been alleviated, global warming has been arrested, and the environment has been protected in an economically sustainable manner. Hydrogen and electricity could team to provide attractive options in transportation and power generation. Interconversion between these two forms of energy suggests on-site utilization of hydrogen to generate electricity, with the electrical power grid serving in energy transportation, distribution utilization, and hydrogen regeneration as needed. A challenging problem in establishing H(2) as a source of energy for the future is the renewable and environmentally friendly generation of large quantities of H(2) gas. Thus, processes that are presently conceptual in nature, or at a developmental stage in the laboratory, need to be encouraged, tested for feasibility, and otherwise applied toward commercialization.

Hydrogen production. Green algae as a source of energy

Hydrogen gas is thought to be the ideal fuel for a world in which air pollution has been alleviated, global warming has been arrested, and the environment has been protected in an economically sustainable manner. Hydrogen and electricity could team to provide attractive options in transportation and power generation. Interconversion between these two forms of energy suggests on-site utilization of hydrogen to generate electricity, with the electrical power grid serving in energy transportation, distribution utilization, and hydrogen regeneration as needed. A challenging problem in establishing H(2) as a source of energy for the future is the renewable and environmentally friendly generation of large quantities of H(2) gas. Thus, processes that are presently conceptual in nature, or at a developmental stage in the laboratory, need to be encouraged, tested for feasibility, and otherwise applied toward commercialization.

Absence of lutein, violaxanthin and neoxanthin affects the functional chlorophyll antenna size of photosystem-II but not that of photosystem-I in the green alga Chlamydomonas reinhardtii

Chlamydomonas reinhardtii double mutant npq2 lor1 lacks the beta, epsilon-carotenoids lutein and loroxanthin as well as all beta,beta-epoxycarotenoids derived from zeaxanthin (e.g. violaxanthin and neoxanthin). Thus, the only carotenoids present in the thylakoid membranes of the npq2 lor1 cells are beta-carotene and zeaxanthin. The effect of these mutations on the photochemical apparatus assembly and function was investigated. In cells of the mutant strain, the content of photosystem-II (PSII) and photosystem-I (PSI) was similar to that of the wild type, but npq2 lor1 had a significantly smaller PSII light-harvesting Chl antenna size. In contrast, the Chl antenna size of PSI was not truncated in the mutant. SDS-PAGE and Western blot analysis qualitatively revealed the presence of all LHCII and LHCI apoproteins in the thylakoid membrane of the mutant. The results showed that some of the LHCII and most of the LHCI were assembled and functionally connected with PSII and PSI, respectively. Photon conversion efficiency measurements, based on the initial slope of the light-saturation curve of photosynthesis and on the yield of Chl a fluorescence in vivo, showed similar efficiencies. However, a significantly greater light intensity was required for the saturation of photosynthesis in the mutant than in the wild type. It is concluded that zeaxanthin can successfully replace lutein and violaxanthin in most of the functional light-harvesting antenna of the npq2 lor1 mutant.