45 research outputs found
BOOST -- A Satellite Mission to Test Lorentz Invariance Using High-Performance Optical Frequency References
BOOST (BOOst Symmetry Test) is a proposed satellite mission to search for
violations of Lorentz invariance by comparing two optical frequency references.
One is based on a long-term stable optical resonator and the other on a
hyperfine transition in molecular iodine. This mission will allow to determine
several parameters of the standard model extension in the electron sector up to
two orders of magnitude better than with the current best experiments. Here, we
will give an overview of the mission, the science case and the payload.Comment: 11 pages, 2 figures, accepted for publication in Phys. Rev.
Detailed knowledge of regional anatomy and anatomical variations is fundamental to achieve successful surgical procedure. Although primary objective of neurosurgery is to restore physiological vital functions, remove intracranial mass and prevent further
Detailed knowledge of regional anatomy and anatomical variations is fundamental to achieve successful surgical procedure. Although primary objective of neurosurgery is to restore physiological vital functions, remove intracranial mass and prevent further brain damage, while preserving tissue and organ integrity, the neurosurgeon takes the risk of impairing non-vital functions. Occasionally, as with the hypoglossal nerve, the impairment of anatomical structures found on surgical route is due to their still barely known anatomical relations and variations. In order to provide an anatomically and surgically oriented classification to guide neurosurgical procedures and to ensure the preservation of nerve integrity, the aim of the present study is to detail the course of the 12th cranial nerve (CN) and to establish anatomical landmarks for surgeons. A combination of anatomical dissection of the neck and oral floor and skull base far lateral approach of 6 cadaveric human heads (3 male, 3 female, age 62+4) was performed, on both sides, to explore and follow the entire course of the 12th CN, from its emergence in the preolivary sulcus to the tongue. Skeletal, muscular and vascular relationships were meticulously analyzed and documented during anatomic and surgical dissections. According to our observations, hypoglossal nerve can be divided into five segments. The first two are intracranial, cisternal and intracanalar, and the other three, namely the descending, horizontal and ascending, are extracranial. Intriguingly, we found unreported relations of the nerve that, apart from their anatomical interest, have tremendous significance for surgeons operating on head and neck. Specifically, the intracanalar segment passes through a venous lacuna that, to the best of our knowledge, was never described before as such. This venous structure drains into the jugular bulb and acts as a sheath between the nerve and the osseous wall of the canal. The nerve in the venous sheath bends and it is elastically fixed to the osseous wall of the canal by fibrous bands. Therefore, the venous lacuna guarantees mobility to the nerve, and cushion the nerve from the bone. As for the descending segment, during its course it has very close relationship with the internal jugular vein, the internal carotid artery, the posterior belly of digastric muscle, and the styloid process and muscles inserting on it. The descending segment provides the ansa hypoglossi, branches to muscles inserting on the styloid process and to the sternocleidomastoid muscle. The horizontal segment has relationship with the intermediate digastric tendon, the stylohyoid, hyoglossus and mylohyoid muscles and the submandibular gland. The ascending segment might be very short and sometimes it is absent. The fifth and last segment becomes deeper at the anterior edge of hyoglossus muscle, and terminates into several branches supplying intrinsic and extrinsic musculature of tongue
Design of a dual species atom interferometer for space
Atom interferometers have a multitude of proposed applications in space
including precise measurements of the Earth's gravitational field, in
navigation & ranging, and in fundamental physics such as tests of the weak
equivalence principle (WEP) and gravitational wave detection. While atom
interferometers are realized routinely in ground-based laboratories, current
efforts aim at the development of a space compatible design optimized with
respect to dimensions, weight, power consumption, mechanical robustness and
radiation hardness. In this paper, we present a design of a high-sensitivity
differential dual species Rb/Rb atom interferometer for space,
including physics package, laser system, electronics and software. The physics
package comprises the atom source consisting of dispensers and a 2D
magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap
based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein
condensate (BEC) creation and interferometry, the detection unit, the vacuum
system for mbar ultra-high vacuum generation, and the
high-suppression factor magnetic shielding as well as the thermal control
system. The laser system is based on a hybrid approach using fiber-based
telecom components and high-power laser diode technology and includes all laser
sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and
switching of the laser beams is carried out on an optical bench using Zerodur
bonding technology. The instrument consists of 9 units with an overall mass of
221 kg, an average power consumption of 608 W (819 W peak), and a volume of 470
liters which would well fit on a satellite to be launched with a Soyuz rocket,
as system studies have shown.Comment: 30 pages, 23 figures, accepted for publication in Experimental
Astronom
STE-QUEST - Test of the Universality of Free Fall Using Cold Atom Interferometry
In this paper, we report about the results of the phase A mission study of the atom
interferometer instrument covering the description of the main payload elements, the
atomic source concept, and the systematic error sources
COVID-19 in rheumatic diseases in Italy: first results from the Italian registry of the Italian Society for Rheumatology (CONTROL-19)
OBJECTIVES:
Italy was one of the first countries significantly affected by the coronavirus disease 2019 (COVID-19) epidemic. The Italian Society for Rheumatology promptly launched a retrospective and anonymised data collection to monitor COVID-19 in patients with rheumatic and musculoskeletal diseases (RMDs), the CONTROL-19 surveillance database, which is part of the COVID-19 Global Rheumatology Alliance.
METHODS:
CONTROL-19 includes patients with RMDs and proven severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) updated until May 3rd 2020. In this analysis, only molecular diagnoses were included. The data collection covered demographic data, medical history (general and RMD-related), treatments and COVID-19 related features, treatments, and outcome. In this paper, we report the first descriptive data from the CONTROL-19 registry.
RESULTS:
The population of the first 232 patients (36% males) consisted mainly of elderly patients (mean age 62.2 years), who used corticosteroids (51.7%), and suffered from multi-morbidity (median comorbidities 2). Rheumatoid arthritis was the most frequent disease (34.1%), followed by spondyloarthritis (26.3%), connective tissue disease (21.1%) and vasculitis (11.2%). Most cases had an active disease (69.4%). Clinical presentation of COVID-19 was typical, with systemic symptoms (fever and asthenia) and respiratory symptoms. The overall outcome was severe, with high frequencies of hospitalisation (69.8%), respiratory support oxygen (55.7%), non-invasive ventilation (20.9%) or mechanical ventilation (7.5%), and 19% of deaths. Male patients typically manifested a worse prognosis. Immunomodulatory treatments were not significantly associated with an increased risk of intensive care unit admission/mechanical ventilation/death.
CONCLUSIONS:
Although the report mainly includes the most severe cases, its temporal and spatial trend supports the validity of the national surveillance system. More complete data are being acquired in order to both test the hypothesis that RMD patients may have a different outcome from that of the general population and determine the safety of immunomodulatory treatments
How future surgery will benefit from SARS-COV-2-related measures: a SPIGC survey conveying the perspective of Italian surgeons
COVID-19 negatively affected surgical activity, but the potential benefits resulting from adopted measures remain unclear. The aim of this study was to evaluate the change in surgical activity and potential benefit from COVID-19 measures in perspective of Italian surgeons on behalf of SPIGC. A nationwide online survey on surgical practice before, during, and after COVID-19 pandemic was conducted in March-April 2022 (NCT:05323851). Effects of COVID-19 hospital-related measures on surgical patients' management and personal professional development across surgical specialties were explored. Data on demographics, pre-operative/peri-operative/post-operative management, and professional development were collected. Outcomes were matched with the corresponding volume. Four hundred and seventy-three respondents were included in final analysis across 14 surgical specialties. Since SARS-CoV-2 pandemic, application of telematic consultations (4.1% vs. 21.6%; p < 0.0001) and diagnostic evaluations (16.4% vs. 42.2%; p < 0.0001) increased. Elective surgical activities significantly reduced and surgeons opted more frequently for conservative management with a possible indication for elective (26.3% vs. 35.7%; p < 0.0001) or urgent (20.4% vs. 38.5%; p < 0.0001) surgery. All new COVID-related measures are perceived to be maintained in the future. Surgeons' personal education online increased from 12.6% (pre-COVID) to 86.6% (post-COVID; p < 0.0001). Online educational activities are considered a beneficial effect from COVID pandemic (56.4%). COVID-19 had a great impact on surgical specialties, with significant reduction of operation volume. However, some forced changes turned out to be benefits. Isolation measures pushed the use of telemedicine and telemetric devices for outpatient practice and favored communication for educational purposes and surgeon-patient/family communication. From the Italian surgeons' perspective, COVID-related measures will continue to influence future surgical clinical practice
Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study
: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p < 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)
Laser Interferometer System Modelling for Drag-Free Satellite Simulations
LISA Pathfinder is the mission that will test the general
concepts and technologies needed for LISA, the Laser
Interferometer Space Antenna for the detection of gravitational
waves. The spacecraft will fly a European payload called LISA
Technology Package (LTP) and a similar US-supplied package
developed for NASA by the Jet Propulsion Laboratory in Pasadena.
The LTP contains two test masses whose position and attitude
relative to the housing/satellite are measured electrostatically,
as well as using a laser interferometer; the main technical goal
for the mission is to demonstrate that a test mass can be put in
pure gravitational free-fall within one order of magnitude from
the requirements for LISA. To ensure that the test
masses are flying in a disturbance-free motion along their
geodesics, challenging performance requirements with respect to
internal and external disturbance rejection must be satisfied by
an overall Drag-Free-System. Detailed simulations are
needed in order to ensure mission success and an End-to-End
simulator is currently under development that aims at verifying
the on-orbit performance of both spacecraft and payload. Since the
performance of the laser interferometer system is expected to
deeply affect the dynamic of both spacecraft and payload, a more
detailed model of the measurements of test masses' position and
attitude needs to be derived and is developed within this work.
Particularly, the architecture of a complete, integrated model of both optics and
electronics has been identified and developed; it allows for
implementing high frequency tasks performed by the system into a
low frequency End-to-End environment and simulating main noise
sources and non-linearities at the level of scientific/technical
requirements. Models have been implemented, mainly, in form of
C/C++ functions (integrated into the SIMULINK environment) and
results prove the feasibility of a sufficiently detailed model of
the laser interferometer system that can run into the performance
simulator.
LISA Pathfinder è la missione che verificherà soluzioni e
tecnologie necessarie alla realizzazione di LISA, Laser
Interferometer Space Antenna per il rilevamento delle onde
gravitazionali. Il carico pagante è costituito dal LISA
Technology Package (LTP) e da un analogo modulo sviluppato dal
Jet Propulsion Laboratory per conto di NASA. L' LTP contiene
due masse di prova la cui posizione e il cui assetto vengono
misurati sia elettrostaticamente che attraverso un sistema di
interferometria laser; il principale obiettivo della missione è
dimostrare che è possibile ottenere un moto di quasi perfetta
caduta libera per una delle masse entro un certo livello di
progetto per la densità spettrale di potenza della accelerazione
corrispondente a rilassare di un ordine di grandezza il requisito
per LISA.
Per far in modo che il moto delle masse, esente nominalmente da possibili disturbi, avvenga
lungo le geodetiche, è necessario che stringenti requisiti di
riduzione di effetti di perturbazione siano soddisfatti da un
Drag-Free-System.
Simulazioni dettagliate sono necessarie allo scopo di
assicurare il successo della missione e un simulatore End-to-End è
attualmente in fase di sviluppo. Poichè la risposta del sistema di
interferometria laser influenza direttamente la dinamica del
satellite e dei sensori inerziali, un modello dettagliato del
sistema di misura di posizione e assetto delle masse di prova deve
essere derivato ed è sviluppato nell' ambito di questa tesi.
In particolare, è stato identificata e sviluppata la architettura di un modello
completo ed integrato dei componenti ottici ed elettronici
(analogici e digitali) che costituiscono la unità di
interferometria laser; esso consente di implementare funzioni ed
operazioni ad alta frequenza in un simulatore End-to-End a bassa
frequenza e di simulare le principali sorgenti di rumore e
non-linearità al livello dei requisiti scientifici e tecnici
definiti per la missione. I modelli sono stati implementati in
forma di funzioni C/C++ integrate in SIMULINK e i risultati
dimostrano che è possibile simulare il sistema in modo
adeguatamente accurato ad un costo computazionale compatibile con
un ambiente End-to-End
Familial Replicating Arachnoidal Cysts: Case Series and Review of Literature
Background: Arachnoid cysts are intra-arachnoid fluid collections covered by a thin membrane that may develop
throughout the cerebrospinal axis. Although the precise causative mechanism is unknown, arachnoid cyst (AC) are
now generally accepted to be developmental anomalies of arachnoid. These lesions have commonly been described
in the literature; however the presence of familial arachnoid cysts is quite rare. Most genetically related AC have been
documented in patients with a known genetic syndrome. The current case report describes a family with four members
affected by an arachnoid cyst in the same region.
Methods: In addition to reviewing the current case, a literature search was conducted using National Library of
Medicine and National Institutes of Health databases to identify articles pertaining to familial Arachnoid cysts. Overall,
32 published articles fit the established review criteria
Results: We describe a family whose members (father and three siblings) present an arachnoid cyst in the same
region (the left middle cranial fossa). The general physical findings in the four members were normal and no clinical
suggestion of a genetic syndrome. None of the members had an increased head size or abnormal cutaneous findings.
Histories of prenatal and perinatal periods were unremarkable. All were born normally at term and none had any history
of intrauterine exposure to infection, drugs, teratogens or trauma. Karyotyping failed to reveal abnormalities.
Conclusion: This report extends previous observations that AC can be familial and supports the hypothesis that
some cases have a genetic aetiology. The lack of chromosomal or genetic studies in these patients supports the need
for additional research into the mechanism of AC formation