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Gori F, Vonci N, Tinturini A, Basagni C, Messina G, De Marco F. Antibiotic consumption and healthcare associated infection in a third level Italian hospital. Eur J Public Health 2020. [DOI: 10.1093/eurpub/ckaa166.696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
The extended length of stay (LoS) is one of the main causes of hospital infections (HAI), followed by an increase in antibiotics consumption. The final step is the development of multiresistant microorganisms, with a consequent increase in costs for the national healthcare system. Aim of this study is to evaluate the prevalence of HAI and to analyze ATB consumption in a teaching hospital
Methods
Between 17-21 June 2019 the infection control team collected the clinical records of 425 patients to perform a point of prevalence analysis (PPA). Eligible patients were hospitalized in surgical and medical wards of the teaching Hospital (615 beds) in Siena, Italy. For each patients according to guidelines of European Centers for Disease Control and Prevention (ECDC 4.2) we searched for evidence of HAI and for all indication of ATB consumption. Data were processed using Stata12
Results
Overall 425 patients have been analyzed (48.24% female), mean age was 60.88 (SD 26.11) years, mean LoS 8.37 (min 1 max 86) days. Patients were admitted mostly in General Medicine wards (48.94%); 34% underwent surgery. 63.8% of patients had Peripheral Venous Catheter, 20% Central Venous Catheter and 31.06% Urinary Catheter. Twenty-nine HAI were discovered (PPA 6.82%); the higher prevalence (19.23%) was in Intensive Care Unit. LoS (OR:1.07;IC95%1.04-1.1) and devices (OR:2.17;IC95%1.39-3.37) were the two variables that significantly influenced the infection risk. Forty-six percent of all patients received ATB, the most used were third generation Cephalosporines (26,18%), followed by Penicillines (24,73%). The main use was to treat community infections (62.12%), followed by medical prophylaxis (30.81%)
Conclusions
PPA of HAI was 6.82%, comparable to 2017 national PPA (6.5%); prolonged LoS is probably the main cause of this result. Our analysis showed that ATB consumption was quite high, in agreement with the Italian prevalence (44.9%), but the percentage of medical prophylaxis was still high.
Key messages
The way to achieve the health care infection control is still long, the length of the hospitalization could be a field to be improved. High consumption of antibiotics for prophylaxis is still the main point to fight in the battle against the multiresistant microorganisms.
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Favilli A, Tiburzi C, Gargaglia E, Cerotto V, Bagaphou TC, Checcaglini A, Bini V, Gori F, Torrioli D, Gerli S. Does epidural analgesia influence labor progress in women aged 35 or more? J Matern Fetal Neonatal Med 2020; 35:1219-1223. [PMID: 32233707 DOI: 10.1080/14767058.2020.1743672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Background: During the last decades, the age of pregnant women significantly increased. The incidence of maternal and labor complications is higher among older women, but conclusive data have not been delivered whether labor epidural analgesia (EA) may affect the duration of labor and delivery outcomes in this population of patients. The aim of this study is to evaluate the effect of EA among women aged over 35 years.Methods: We retrospectively reviewed medical records of all, singleton, at term deliveries, laboring with EA, between December 2011 and October 2017. Women aged ≥35 years (study group) were compared with women aged <35 years (control group) to evaluate EA effects on the duration of labor and neonatal outcome.Results: The study enrolled 459 women with EA: 122 women were included in the study group and 337 in the control group. The multiple regression analysis showed that parity was an independent variable for a shorter dilation period (p = .002), second stage length (p = .0001) and for the total labor duration (p = .0001); neonatal weight was significant for a shorter dilation period (p = .005) and for the total labor duration (p = .002); maternal age and cervical dilatation at the beginning of EA did not influence neither the period of the labor stages nor the total labor duration (p > .05).Conclusions: Results of this study indicate that women aged ≥35 with EA may have labor duration and neonatal short-term outcomes similar to younger women with EA.
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Pasqualucci A, Al-Sibaie A, Vaidyan KPT, Paladini A, Nadhari MY, Gori F, Greiss HF, Properzi M, Al Ani OSM, Godwin A, Syedkazmi AH, Elhanf OA, Varrassi G. Epidural Corticosteroids, Lumbar Spinal Drainage, and Selective Hemodynamic Control for the Prevention of Spinal Cord Ischemia in Thoracoabdominal Endovascular Aortic Repair: A New Clinical Protocol. Adv Ther 2020; 37:272-287. [PMID: 31721112 DOI: 10.1007/s12325-019-01146-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Indexed: 12/16/2022]
Abstract
INTRODUCTION In patients undergoing thoracoabdominal aorta repair, spinal cord ischemia (SCI) remains one of the most common and important complications resulting in transient paraparesis through to permanent flaccid paraplegia. In this manuscript, after a brief introduction to spinal cord ischemia complication and its prevention in thoracoabdominal endovascular aortic repair (TEVAR), we propose a new clinical protocol potentially able to prevent such complication. METHODS The proposed protocol suggests the use of high dosages of corticosteroids by epidural route, along with drainage of cerebrospinal fluid and controlled vascular hypertension, to reduce the incidence of SCI in TEVAR. Moreover, we paid particular attention to the control of the hemodynamic parameters to obtain adequate peripheral tissue perfusion (oxygen delivery), including in the spinal cord. RESULTS We applied this new protocol in 50 consecutive patients treated with TEVAR for thoracoabdominal aortic aneurysms (TAAs); 47 patients completed the procedure: 27 patients Crawford type I and 20 Crawford type II. Three patients died during surgery because of untreatable aneurysm rupture. The results show that in all patients there were no cases of SCI, after 5 days from TEVAR. DISCUSSION To the best of our knowledge, there are no clinical studies on the use of epidural corticosteroids in patients undergoing treatment of aortic syndrome (both in "open surgery" and endovascular aortic repair). This initial study on 50 consecutive patients has shown that the clinical protocol used could be of great interest to prevent one of the worse complications of TEVAR. Its limitations are the low number of patients studied till now, and the non-randomized protocol adopted. Further studies would be necessary. CONCLUSION Our experience and the results obtained with this new perioperative protocol with epidural corticosteroid and accurate hemodynamic control have been encouraging and it seems a valid proposal to be explored in future by well-structured prospective, randomized protocols.
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Montrucchio G, Cerotto V, Vailati D, Capozzoli G, Gori F, Brazzi L. Skin microbiome and placement of vascular access: A solved problem? J Infect Prev 2019; 20:301-302. [PMID: 31762793 DOI: 10.1177/1757177419863850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Bagaphou TC, Cerotto V, Gori F. Efficacy of tapentadol prolonged release for pre- and post-operative low back pain: a prospective observational study. EUROPEAN REVIEW FOR MEDICAL AND PHARMACOLOGICAL SCIENCES 2019; 23:14-20. [PMID: 31755078 DOI: 10.26355/eurrev_201911_19377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Low back pain (LBP) is a highly prevalent chronic pain condition with a neuropathic component of pain that limits the benefits of classical opioids. Tapentadol is an innovative drug for the treatment of chronic severe pain, with a dual mechanism of action combining µ-opioid receptors agonism and noradrenaline re-uptake inhibition (NRI). Its efficacy is equal to that of strong opioids, with a better tolerability profile and a consequently lower risk of treatment discontinuation. The aim of this study was to evaluate the analgesic efficacy and tolerability of tapentadol prolonged release (PR) vs. other analgesics in patients with moderate-to-severe neuropathic low back pain, before and after back surgery. PATIENTS AND METHODS The primary endpoints of the study were the rate of response to treatment, measured as ≥30% reduction in pain intensity on the Numeric Rating Scale (NRS), and tapentadol PR efficacy for pain relief. The secondary endpoints were the improvements of the neuropathic component of pain and of sleep quality. RESULTS A total of 40 patients were enrolled in the study, receiving either tapentadol PR (n=21, 52.5%) or other analgesics (n=19, 47.5%), both before and after surgery. The rate of response to treatment was statistically in favor of tapentadol PR (p<0.01). The reduction in pain intensity was statistically significant in the group treated with tapentadol PR, both before and after surgery (p<0.01), with a complete resolution of pain 90 days after surgery. The quality of sleep after surgery improved more in patients treated with tapentadol PR than in the comparator group (p<0.01), with 100% of the patients reporting a "good" sleep quality 2 months after surgery. CONCLUSIONS Tapentadol PR was well tolerated by all patients, and its efficacy for pain relief was also confirmed in our small group of "real-life" patients with chronic, severe low back pain. Overall, the tolerability of this treatment may help to improve patients' quality of life, which is frequently compromised because of pain and its related comorbidities.
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Mammucari M, Maggiori E, Antonaci L, Fanelli R, Giorgio C, George F, Mouhli N, Rahali H, Ksibi I, Maaoui R, Bifarini B, Ferrara PE, Gori F, Ronconi G. Intradermal therapy recommendations for standardization in localized pain management by the Italian Society of Mesotherapy. Minerva Med 2019; 112:298-300. [PMID: 31726813 DOI: 10.23736/s0026-4806.19.06278-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Nante N, Kundisova L, Gori F, Martini A, Battisti F, Giovannetti L, Messina G, Chellini E. The decomposition of life expectancy for age and cause of death in Tuscany, Italy. Eur J Public Health 2019. [DOI: 10.1093/eurpub/ckz185.638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Introduction
Changing of life expectancy at birth (LE) over time reflects variations of mortality rates of a certain population. Italy is amongst the countries with the highest LE, Tuscany ranks fifth at the national level. The aim of the present work was to evaluate the impact of various causes of death in different age groups on the change in LE in the Tuscany region (Italy) during period 1987-2015.
Material and methods
Mortality data relative to residents that died during the period between 1987/1989 and 2013/2015 were provided by the Tuscan Regional Mortality Registry. The causes of death taken into consideration were cardiovascular (CVS), respiratory (RESP) and infective (INF) diseases and cancer (TUM). The decomposition of LE gain was realized with software Epidat, using the Pollard’s method.
Results
The overall LE gain during the period between two three-years periods was 6.7 years for males, with a major gain between 65-89, and 4.5 years for females, mainly improved between 75-89, <1 year for both sexes. The major gain (2.6 years) was attributable to the reduction of mortality for CVS, followed by TUM (1.76 in males and 0.83 in females) and RESP (0.4 in males; 0.1 in females). The major loss of years of LE was attributable to INF (-0.15 in females; -0.07 in males) and lung cancer in females (-0.13), for which the opposite result was observed for males (gain of 0.62 years of LE).
Conclusions
During the study period (1987-2015) the gain in LE was major for males. To the reduction of mortality for CVS have contributed to the tempestuous treatment of acute CVS events and secondary CVS prevention. For TUM the result is attributable to the adherence of population to oncologic screening programmes. The excess of mortality for INF that lead to the loss of LE can be attributed to the passage from ICD-9 to ICD-10 in 2003 (higher sensibility of ICD-10) and to the diffusion of multi-drug resistant bacteria, which lead to elevated mortality in these years.
Key messages
The gain in LE during the period the 1987-2015 was higher in males. The major contribution to gain in LE was due to a reduction of mortality for CVS diseases.
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Gori F, Kundisova L, Bezzini D, Martini A, Giovannetti L, Chellini E, Nante N, Messina G, Battaglia MA. Mortality trends for multiple sclerosis in Italy. Eur J Public Health 2019. [DOI: 10.1093/eurpub/ckz186.205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Multiple sclerosis (MS) is the immune-mediated inflammatory disease affecting myelinated axons of the central nervous system with enormous socio-economic impact. The aim of this study was to analyze mortality trends for MS in Italy.
Methods
The mortality data relative to period 1980-2015 were provided by Italian Institute of Statistics, data were aggregated in 5 intervals (1980-1986; 1987-1993; 1994-2000; 2001-2008; 2008-2015). The Age-Standardized mortality Rates (SR) with respective 95% confidence intervals (95%CI) were calculated (using the European standard 2013) in order to evaluate the mortality trends (in confrontation to the initial period) and Standardized Mortality Ratios (SMR), in order to confront mortality in 5 major geographic areas: North-East (NE), North-West (NW), Central Italy (CI), South Italy (SI) and Islands (I).
Results
During the study period 4959 deaths for males and 7433 for females were observed. The SRs were significantly higher for females (0.71;95%CI:0.70-0.73 vs. 0.56; 95%CI:0.54-0.57).
Significantly higher SMR were observed for both sexes in I (M:123.3 vs F:112.7), for females also in NE (106.5) and NW (115.8). Significantly lower SMR for both sexes were observed in SI (M:88.8; F:71.4) and for males in CI (90.9).
The observed SRs during the five intervals for males were: 0.65(95%CI 0.60-0.69); 0.52 (95%CI 0.49-0.56); 0.46 (95%CI 0.43-0.49); 0.53 (95%CI 0.49-0.56); 0.59 (95%CI 0.56-0.62); and for females: 0.69 (0.65-0.73); 0.69 (0.65-0.73); 0.61 (0.58-0.65); 0.68 (0.65-0.72); 0.81(0.77-0.84); respectively. An initial decrease of SRs was observed for males until 2001-2007 in confrontation to the initial period (p < 0.05). For females significant increase of SRs was observed in 2008-2015 (p < 0.05).
Conclusions
An increase of mortality for MS, observed for females, especially after 2000 may reflect the raising prevalence of MS in Italy. Important geographical differences were observed for five main areas.
Key messages
During the study period an increase of mortality for MS was observed for females. Important differences were observed between five main Italian geographic areas.
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Gori F, Vonci N, Santoriello G, Quercioli C, Messina G, Sancasciani S. Hospital acquired infection, evaluation of point of prevalence in a 147 beds italian hospital. Eur J Public Health 2019. [DOI: 10.1093/eurpub/ckz186.502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Hospital Acquired Infections (HAI) have become a public health priority worldwide, leading to higher medical costs, prolonged hospital stays, and increased mortality. The point of prevalence analysis (PPA) of HAI and antibiotics (ATB) consumption is extremely relevant for its social and economic impact. Aim of this study is to evaluate the prevalence of HAI and to analyze ATB consumption in 147 beds hospital.
Material and Methods
This prevalence study was conduced on March 23, 2018, we analyzed the clinical documentation of 78 patients hospitalized in the Hospital of Val D’Elsa, Siena, Italy and searched for evidence of HAI and for all indication of ATB therapy in all hospital wards. HAI were defined according to guidelines of European Centers for Disease Control and Prevention (ECDC 4.2) using Stata 12.
Results
We analyzed a total of 78 patients (51,3% female), average age was 71,6 (sd ± 23,4) years, mean lenght of stay 7,2 (sd ± 7,9) days. Patients included in the study were recovered mostly in General Medicine ward (62,8%); 23% of patients underwent surgery. Fifty-one point three of patients had Peripheral Venous Catheter, 17,9% Central Venous Catheter and 47,4% Urinary Catheter. Three infections were discovered (PPA 3,8%); 2 HAIs were found in Medicine ward, the third one in the Intensive Care Unit. The chi-square test did not show statistically significant differences with the last year’s results in the same wards (p = 0.3305). Fifty-four percent of all patients received ATB, the most used class were third generation Cephalosporines (50%), followed by Carbapenems (19%) and Fluoroquinolones (7%).
Conclusions
PPA of HAI was 3,8%, comparable to last year’s (3,5%). This is a positive result when compared to regional and national point prevalence study realized by ECDC in 2012 (6,2% in Tuscany Region, 6% in Italy). Our analysis showed that ATB consumption was quite high: and it is in agreement with those provided by the Tuscany Region.
Key messages
in our hospital we report an excellent result about the pint of prevalence of hospital acquired infections 3,8%. The antibiotics consumption in our hospital is quite high, the most frequently used antibiotic class is the third generation Cephalosporines.
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Gori F, Cuccaro C, Santamaria M, Cardaci R, Burgassi S, Battaglia MA, Messina G. Could chips and nuts be vector of food-borne outbreaks during happy hour? Eur J Public Health 2019. [DOI: 10.1093/eurpub/ckz185.312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
A Greater tendency to eat meals outside the home has led to an increase in the attendance of restaurants, cafes, and fast food. That is one of the reasons why the global interest in handling food has risen over the years. The aim of this study is to understand the level of microbial contamination in the food that is served along happy hour in cafe.
Methods
This cross sectional pilot study was performed from April to May 2018 in the city of Siena, central Italy (<60000 citizens). Ten cafes were randomly selected. Samples of peanuts and potatoes were obtained in three different moments, at the beginning (T0), in the middle (T1), at the end (T2) of happy hours events. Collection of the samples was obtained using sterile kit and laboratory analysis was conducted in the University lab. The samples were located on selective medium and the growth of microbial pathogens were checked at 24 and 48 hours. The tested microorganisms were Enterococci, Staphylococci, Coliforms bacteria, Molds, and Yeasts. The statistical analyses were conducted using the Wilcoxon test using Stata 12.
Results
A significant Yeasts contamination appeared only on chips at T0, while within T0 and T1 we found a significant increase of Enterococci, Staphylococci, and Yeasts (p < 0.05) both in peanuts and chips. Comparing T1 and T2 only Yeasts showed significant growth in potatoes (p = 0.04). Between T0 and T2 we also found the growth of Coliforms bacteria in peanuts (p = 0.03).
Conclusions
We showed an increase in the microbial load associated with food handling, mostly of Enterococci. Long exposure time increased the likelihood of contamination and the possibility to exceed the dose for the occurrence of good outbreak. It is likely that offering small portions of handling food would reduce the manipulation by participants and the risk of food-borne outbreaks.
Key messages
Define the most frequent microrganisms could be associated with backed food and evaluate which one of these can exceed the dose for the occurrence of disease in long time. Reflect on the likelihood that the risk of food-borne outbreak caused by manipulation of happy hour participants, may result in an increase in hospital admissions.
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Santarsiero M, Gori F, Alonzo M. Higher-order twisted/astigmatic Gaussian Schell-model cross-spectral densities and their separability features. OPTICS EXPRESS 2019; 27:8554-8565. [PMID: 31052670 DOI: 10.1364/oe.27.008554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
Adding a twist phase term to the cross-spectral density (CSD) function of a partially coherent source can be done if and only if the resulting function remains nonnegative definite. Constraints on the twist term that guarantee the validity of the resulting CSD have been derived only for Twisted Gaussian Schell-model (TGSM) sources. Here, an infinite family of higher-order TGSM sources is introduced, whose CSDs are expressed as products of the CSD of a standard TGSM source times Hermite polynomials of arbitrary orders and suitable arguments. All the members present the same twist term and for all of them the twist-coherence constraint keeps obeying the form valid for a standard TGSM source. They can be used as building blocks for constructing an endless number of valid twisted CSDs, with an assigned value of the twist parameter and intensity and/or coherence features that can be very different from those of a standard TGSM source. Through partial transposition, higher-order TGSM CSDs are converted into higher-order Astigmatic Gaussian Schell-model (AGSM) CSDs. The problem of the separability of higher-order TGSM and AGSM CSDs is addressed, and conditions ensuring their separability are derived.
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Accardo G, Santis PD, Gori F, Guattari G, Webster JM. The Use of Speckle Interferometry in the Study of Large Works of Art. ACTA ACUST UNITED AC 2018. [DOI: 10.1080/00223638.1985.12035793] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Santis PD, Gori F, Guattari G, Palma C, Webster JM. Measurement of Spatial Coherence through Speckle Interferometry. ACTA ACUST UNITED AC 2018. [DOI: 10.1080/00223638.1985.12035799] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Gori F, Kundisova L, Bocci G, Quercioli C, Santoriello G, Sancasciani S, Messina G, Nante N. Point prevalence study of hospital acquired infection in an italian hospital. Eur J Public Health 2018. [DOI: 10.1093/eurpub/cky214.264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Tiburzi C, Cerotto V, Gargaglia E, Carli L, Gori F. Pectoral nerve block II with programmed intermittent bolus of local anesthetic and postoperative pain relief in breast surgery. Minerva Anestesiol 2018; 85:201-202. [PMID: 30207137 DOI: 10.23736/s0375-9393.18.13027-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Alonzo M, Santarsiero M, Gori F. Maximizing Young fringe visibility with a universal SU2 polarization gadget. OPTICS LETTERS 2018; 43:2844-2847. [PMID: 29905704 DOI: 10.1364/ol.43.002844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
When a Young interferometer is fed by a general electromagnetic field, the fringe visibility may change upon insertion of an anisotropic optical element over one of the interferometer pinholes. The maximum visibility that the fringes may exhibit in this way is theoretically known, but no direct experimental check seems to be available. Here we discuss the scheme of an experimental test. In particular, maximum fringe visibility is obtained with a three-component universal SU2 polarization gadget for arbitrary coherence features of the illuminating field. Confirming results obtained with a suitable experimental setup are presented.
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Piquero G, Santarsiero M, Martínez-Herrero R, de Sande JCG, Alonzo M, Gori F. Partially coherent sources with radial coherence. OPTICS LETTERS 2018; 43:2376-2379. [PMID: 29762596 DOI: 10.1364/ol.43.002376] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 04/08/2018] [Indexed: 05/28/2023]
Abstract
Partially coherent sources with radial coherence are proposed. They present a circularly symmetric intensity profile and a degree of coherence whose absolute value only depends on the angular difference between the two considered points. In particular, the source is completely coherent at pairs of points belonging to the same radius. The modal structure of such sources is determined in the general case, and conditions are derived under which the field propagated in paraxial approximation remains radially coherent at any transverse plane. In such cases, the angular dependence of the correlation function is preserved upon propagation, although the intensity profile generally changes. An example of this kind of source has been experimentally synthesized by means of a simple setup, and its coherence characteristics have been tested by means of a Young interferometer.
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Gori F, Santarsiero M. Devising genuine twisted cross-spectral densities. OPTICS LETTERS 2018; 43:595-598. [PMID: 29400849 DOI: 10.1364/ol.43.000595] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 12/30/2017] [Indexed: 06/07/2023]
Abstract
Sticking a twist to a partially coherent source cannot be done at will, since the result can violate the definiteness property of the corresponding cross-spectral density. As a matter of fact, the study of twisted sources has been mainly concentrated on the original case proposed by Simon and Mukunda [J. Opt. Soc. Am. A10, 95 (1993)JOAOD60740-323210.1364/JOSAA.10.000095] of circularly symmetric Gaussian Schell-model sources. Here, we discuss a modeling procedure that can be used to generate numberless genuine twisted sources without symmetry constraints. As geometrically simple examples, two cases of non-Gaussian twisted sources endowed with circular or rectangular symmetry are explicitly worked out.
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Santarsiero M, Martínez-Herrero R, Maluenda D, de Sande JCG, Piquero G, Gori F. Synthesis of circularly coherent sources. OPTICS LETTERS 2017; 42:4115-4118. [PMID: 29028026 DOI: 10.1364/ol.42.004115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/12/2017] [Indexed: 06/07/2023]
Abstract
An experiment is presented in which a partially coherent source endowed with circular coherence is generated. The source is synthesized through a time averaging procedure, so that the mutual intensity is used as the basic correlation function. The correlation between points at different radial distances from the source center is tested by means of a Young interferometer. To confirm the perfect coherence among points along a circle concentric with the source center, the Young mask is replaced by an array of equally spaced pinholes arranged along a circle. The observed pattern is identical to that produced by the same mask, illuminated by perfectly coherent light.
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Beardmore RE, Peña-Miller R, Gori F, Iredell J. Antibiotic Cycling and Antibiotic Mixing: Which One Best Mitigates Antibiotic Resistance? Mol Biol Evol 2017; 34:802-817. [PMID: 28096304 PMCID: PMC5400377 DOI: 10.1093/molbev/msw292] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Can we exploit our burgeoning understanding of molecular evolution to slow the progress of drug resistance? One role of an infection clinician is exactly that: to foresee trajectories to resistance during antibiotic treatment and to hinder that evolutionary course. But can this be done at a hospital-wide scale? Clinicians and theoreticians tried to when they proposed two conflicting behavioral strategies that are expected to curb resistance evolution in the clinic, these are known as “antibiotic cycling” and “antibiotic mixing.” However, the accumulated data from clinical trials, now approaching 4 million patient days of treatment, is too variable for cycling or mixing to be deemed successful. The former implements the restriction and prioritization of different antibiotics at different times in hospitals in a manner said to “cycle” between them. In antibiotic mixing, appropriate antibiotics are allocated to patients but randomly. Mixing results in no correlation, in time or across patients, in the drugs used for treatment which is why theorists saw this as an optimal behavioral strategy. So while cycling and mixing were proposed as ways of controlling evolution, we show there is good reason why clinical datasets cannot choose between them: by re-examining the theoretical literature we show prior support for the theoretical optimality of mixing was misplaced. Our analysis is consistent with a pattern emerging in data: neither cycling or mixing is a priori better than the other at mitigating selection for antibiotic resistance in the clinic. Key words: antibiotic cycling, antibiotic mixing, optimal control, stochastic models.
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Santarsiero M, Martínez-Herrero R, Maluenda D, de Sande JCG, Piquero G, Gori F. Partially coherent sources with circular coherence. OPTICS LETTERS 2017; 42:1512-1515. [PMID: 28409785 DOI: 10.1364/ol.42.001512] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A new class of partially coherent light sources is introduced. At the source plane, they exhibit perfect coherence along any annulus that is concentric to the source center. Between two points at different distances from the center, coherence can be partial or even vanishing. Such sources can be synthesized by using a generalized form of van Cittert-Zernike theorem where axial sources are used. Beams radiated by this type of source are analyzed at the source plane and upon free propagation for some simple cases.
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Reding-Roman C, Hewlett M, Duxbury S, Gori F, Gudelj I, Beardmore R. The unconstrained evolution of fast and efficient antibiotic-resistant bacterial genomes. Nat Ecol Evol 2017; 1:50. [DOI: 10.1038/s41559-016-0050] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 12/09/2016] [Indexed: 11/09/2022]
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Barbieri S, Feltracco P, Snenghi R, Vettore G, Ravaioli C, Franchi M, Previato S, Bergamini M, Stefanati A, Donato D, Carretta G, Rubini S, Frisoni P, Omizzolo L, Gori F, El Mazloum R, Gaudio RM. Drinking games: real-life hazardous challenges which probably increase ‘personal branding’. Eur J Public Health 2016. [DOI: 10.1093/eurpub/ckw175.084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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49
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Borghi R, Gori F, Guattari G, Santarsiero M. Shape-invariant difference between two Gaussian Schell-model beams. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2015; 32:790-796. [PMID: 26366902 DOI: 10.1364/josaa.32.000790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The difference between two Gaussian Schell-model cross-spectral densities can give a new genuine correlation function if suitable conditions are met. Generally speaking, the structure of such cross-spectral density changes in a complicated way upon propagation. We consider here the notable exception of shape-invariant beams, and we investigate their intensity and coherence properties. The modal analysis of this class of cross-spectral densities is exploited to devise a synthesis scheme for this type of beam.
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Gori F, Santarsiero M. Twisted Gaussian Schell-model beams as series of partially coherent modified Bessel-Gauss beams. OPTICS LETTERS 2015; 40:1587-1590. [PMID: 25831391 DOI: 10.1364/ol.40.001587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We show that twisted Gaussian Schell-model (TGSM) beams can be represented through an incoherent superposition of partially coherent beams carrying optical vortices and whose cross-spectral densities are expressed in terms of modified Bessel functions. Moreover, starting from this result, we show that the modal expansion of the cross-spectral density of a TGSM source can be directly obtained through simple mathematics.
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