50 research outputs found
Nonlinear Magneto-Optical Rotation with Amplitude-Modulated Light: AMOR
A new technique of nonlinear magneto-optical rotation with amplitude
modulated light is developed. The technique is an alternative to its
counterpart with frequency modulated light and can be applied to sensitive
measurements of magnetic fields ranging from microgauss to the Earth-field
level. The rotation signals exhibit nontrivial features like narrowed
non-Lorentzian lineshapes and multi-component resonances.Comment: 3 pages, 4 figure
Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications
Superparamagnetic iron oxide nanoparticles
can providemultiple benefits for biomedical applications
in aqueous environments such asmagnetic separation or
magnetic resonance imaging. To increase the colloidal
stability and allow subsequent reactions, the introduction
of hydrophilic functional groups onto the particles’
surface is essential. During this process, the original
coating is exchanged by preferably covalently bonded
ligands such as trialkoxysilanes. The duration of the
silane exchange reaction, which commonly takes more
than 24 h, is an important drawback for this approach. In
this paper, we present a novel method, which introduces
ultrasonication as an energy source to dramatically
accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove
the generic character, different functional groups were
introduced on the surface including polyethylene glycol
chains, carboxylic acid, amine, and thiol groups. Their
colloidal stability in various aqueous buffer solutions as
well as human plasma and serum was investigated to
allow implementation in biomedical and sensing
applications.status: publishe
A new MRI rating scale for progressive supranuclear palsy and multiple system atrophy: validity and reliability
AIM
To evaluate a standardised MRI acquisition protocol and a new image rating scale for disease severity in patients with progressive supranuclear palsy (PSP) and multiple systems atrophy (MSA) in a large multicentre study.
METHODS
The MRI protocol consisted of two-dimensional sagittal and axial T1, axial PD, and axial and coronal T2 weighted acquisitions. The 32 item ordinal scale evaluated abnormalities within the basal ganglia and posterior fossa, blind to diagnosis. Among 760 patients in the study population (PSP = 362, MSA = 398), 627 had per protocol images (PSP = 297, MSA = 330). Intra-rater (n = 60) and inter-rater (n = 555) reliability were assessed through Cohen's statistic, and scale structure through principal component analysis (PCA) (n = 441). Internal consistency and reliability were checked. Discriminant and predictive validity of extracted factors and total scores were tested for disease severity as per clinical diagnosis.
RESULTS
Intra-rater and inter-rater reliability were acceptable for 25 (78%) of the items scored (≥ 0.41). PCA revealed four meaningful clusters of covarying parameters (factor (F) F1: brainstem and cerebellum; F2: midbrain; F3: putamen; F4: other basal ganglia) with good to excellent internal consistency (Cronbach α 0.75-0.93) and moderate to excellent reliability (intraclass coefficient: F1: 0.92; F2: 0.79; F3: 0.71; F4: 0.49). The total score significantly discriminated for disease severity or diagnosis; factorial scores differentially discriminated for disease severity according to diagnosis (PSP: F1-F2; MSA: F2-F3). The total score was significantly related to survival in PSP (p<0.0007) or MSA (p<0.0005), indicating good predictive validity.
CONCLUSIONS
The scale is suitable for use in the context of multicentre studies and can reliably and consistently measure MRI abnormalities in PSP and MSA. Clinical Trial Registration Number The study protocol was filed in the open clinical trial registry (http://www.clinicaltrials.gov) with ID No NCT00211224
Regional Practice Variation and Outcomes in the Standard Versus Accelerated Initiation of Renal Replacement Therapy in Acute Kidney Injury (STARRT-AKI) Trial: A Post Hoc Secondary Analysis
OBJECTIVES: Among patients with severe acute kidney injury (AKI) admitted to the ICU in high-income countries, regional practice variations for fluid balance (FB) management, timing, and choice of renal replacement therapy (RRT) modality may be significant. DESIGN: Secondary post hoc analysis of the STandard vs. Accelerated initiation of Renal Replacement Therapy in Acute Kidney Injury (STARRT-AKI) trial (ClinicalTrials.gov number NCT02568722). SETTING: One hundred-fifty-three ICUs in 13 countries. PATIENTS: Altogether 2693 critically ill patients with AKI, of whom 994 were North American, 1143 European, and 556 from Australia and New Zealand (ANZ). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Total mean FB to a maximum of 14 days was +7199 mL in North America, +5641 mL in Europe, and +2211 mL in ANZ (p < 0.001). The median time to RRT initiation among patients allocated to the standard strategy was longest in Europe compared with North America and ANZ (p < 0.001; p < 0.001). Continuous RRT was the initial RRT modality in 60.8% of patients in North America and 56.8% of patients in Europe, compared with 96.4% of patients in ANZ (p < 0.001). After adjustment for predefined baseline characteristics, compared with North American and European patients, those in ANZ were more likely to survive to ICU (p < 0.001) and hospital discharge (p < 0.001) and to 90 days (for ANZ vs. Europe: risk difference [RD], -11.3%; 95% CI, -17.7% to -4.8%; p < 0.001 and for ANZ vs. North America: RD, -10.3%; 95% CI, -17.5% to -3.1%; p = 0.007). CONCLUSIONS: Among STARRT-AKI trial centers, significant regional practice variation exists regarding FB, timing of initiation of RRT, and initial use of continuous RRT. After adjustment, such practice variation was associated with lower ICU and hospital stay and 90-day mortality among ANZ patients compared with other regions
SCA15 due to large ITPR1 deletions in a cohort of 333 white families with dominant ataxia
BACKGROUND: Deletions in ITPR1, coding for the inositol-triphosphate receptor type 1, have been recently identified in spinocerebellar ataxia type 15 (SCA15). OBJECTIVE: To determine the frequency and the phenotypical spectrum of SCA15. DESIGN: Taqman polymerase chain reaction (258 index cases) or single-nucleotide polymorphism genome-wide genotyping (75 index cases). SETTING: A collaboration between the Centre de Recherche de l'Institut de Cerveau et de la Moelle Epiniere of the Salpetriere Hospital (Paris, France) and the Molecular Genetics Unit of the National Institute of Aging (Bethesda, Maryland). Patients Index cases of 333 families with autosomal dominant cerebellar ataxia negative for CAG repeat expansions in coding exons. MAIN OUTCOME MEASURES: Detection of ITPR1 copy number alterations. RESULTS: A deletion of ITPR1 was found in 6 of 333 families (1.8%), corresponding to 13 patients with SCA15. Age at onset ranged from 18 to 66 years (mean [SD] age, 35 [16] years). The symptom at onset was cerebellar gait ataxia, except in 1 patient with isolated upper limb tremor. Although families were tested irrespective of their phenotype, patients with SCA15 had a homogeneous phenotype and were characterized by a slowly progressive cerebellar ataxia. However, pyramidal signs (2 patients) and mild cognitive problems (2 patients) were occasionally present. Radiologic findings showed global or predominant vermian cerebellar atrophy in all patients. CONCLUSIONS: In this series, ITPR1 deletions were rare and accounted for approximately 1% of all autosomal dominant cerebellar ataxias. The SCA15 phenotype mostly consists of a slowly progressive isolated cerebellar ataxia with variable age at onset; an additional pyramidal syndrome and problems in executive functions may be present
Nd:YAG laser diode-pumped directly into the emitting level at 938 nm
International audienc
Highly efficient Nd:YVO4 laser by direct in-band diode pumping at 914 nm
We present the first demonstration of Nd:YVO4 laser diode-pumped directly in band at 914-nm. We achieved a slope efficiency of 80.7 % by extracting 11.5W at 1064-nm for 14.6W of absorbed pump power at 914-nm.</jats:p
