Examining the experiences of vulnerably housed patients visiting Kingston, Ontario's emergency departments: a qualitative analysis.

INTRODUCTION: Vulnerably housed individuals access emergency departments (EDs) more frequently than the general population. Despite Canada's universal public health care system, vulnerably housed persons face structural barriers to care and experience discrimination from healthcare providers. This study examines how vulnerably housed persons perceive their experience of care in the ED and Urgent Care Center (UCC) in Kingston, Ontario and aims to develop strategies for improving care for this group. METHODS: As part of a larger mixed-methods study, narratives were collected from participants attending the ED/UCC as well as community-based partner organizations, asking them to describe an experience of a recent ED visit (< 24 months). Participants could identify as members of up to three equity-deserving groups (EDGs) (for example homeless, part of an ethnic minority, having a disability, experiencing mental health issues). Coding and thematic analysis were completed for the experiences of participants who identified as being vulnerably housed (n = 171). Results were presented back to individuals with lived experience and service providers working with clients with unstable housing. RESULTS: Participants reported judgement related to a past or presumed history of mental health or substance use and based on physical appearance. They also often felt unheard and that they were treated as less than human by healthcare providers. Lack of effective communication about the ED process, wait times, diagnosis, and treatment led to negative care experiences. Participants reported positive experiences when their autonomy in care-decision making was respected. Furthermore, having a patient-centered approach to care and addressing specific patient needs, identities and priorities led to positive care experiences. CONCLUSIONS: The ED care experiences of vulnerably housed persons may be improved through healthcare provider training related to trauma-informed and patient-centered care and communication strategies in the ED. Another potential strategy to improve care is to have advocates accompany vulnerably housed persons to the ED. Finally, improving access to primary care may lead to reduced ED visits and better longitudinal care for vulnerably housed persons.

High-speed THz spectroscopic imaging at ten kilohertz pixel rate with amplitude and phase contrast.

By combining the advantages of the high-speed ASOPS technology and efficient THz generation, we have realized a high-speed laser-based spectroscopic THz imaging system with more than 10,000 pixels per second acquisition speed and an excellent signal-to-noise ratio of more than 100. Unlike THz line cameras or mm-wave intensity detectors, the present device allows for a much higher spatial resolution and attributes each imaging pixel with phase and amplitude information up to several THz while simultaneously maintaining a very high scanning speed unmatched by any other technique presented so far. The high-speed acquisition allows for samples to be scanned even at sample velocities of 5 m/s or higher while preserving the fundamental resolution limit of the THz radiation, which is on the order of 500 µm in the present case.

[Preferred Medical Specialties of Medical Students in Contrast to the Need for General Practitioners in Saxony]. / Facharztpräferenzen von Medizinstudierenden im Kontrast zum Bedarf an Allgemeinmedizinern in Sachsen.

Aim of the study: Especially in the rural areas of Germany, there are not enough general practitioners (GPs) for primary care. Preferred medical specialties of medical students can help get an estimate of the number of future GPs. This study compares this estimate to the current need for GPs in Saxony. Methods: 587 medical students at the second, sixth and tenth semester were invited to take part in an anonymous cross-sectional study regarding their specialty preferences at the Technical University Dresden. Based on the data of the medical requirements for Saxony, 4 model calculations were generated for comparison of the estimated numbers of future GPs and the current need for GPs. Results: The most commonly preferred medical specialties were surgery (19.1%), internal medicine (12.9%), pediatrics (11.6%) and general practice (9.9%). A significant increase in specialist preference for GP was observed from the sixth (4.9%) to the tenth semester (14.0%). The model calculations show that approximately 29% to 111% of the open positions for GPs could be filled by the potential new GPs from Dresden. Conclusion: Currently, medical students planning to become GPs cannot meet the corresponding need for GPs. Future studies should include the points of view of students, continuing education assistants, GPs and patients.

Frequency comb metrology with an optical parametric oscillator.

We report on the first demonstration of absolute frequency comb metrology with an optical parametric oscillator (OPO) frequency comb. The synchronously-pumped OPO operated in the 1.5-µm spectral region and was referenced to an H-maser atomic clock. Using different techniques, we thoroughly characterized the frequency noise power spectral density (PSD) of the repetition rate frep, of the carrier-envelope offset frequency fCEO, and of an optical comb line νN. The comb mode optical linewidth at 1557 nm was determined to be ~70 kHz for an observation time of 1 s from the measured frequency noise PSD, and was limited by the stability of the microwave frequency standard available for the stabilization of the comb repetition rate. We achieved a tight lock of the carrier envelope offset frequency with only ~300 mrad residual integrated phase noise, which makes its contribution to the optical linewidth negligible. The OPO comb was used to measure the absolute optical frequency of a near-infrared laser whose second-harmonic component was locked to the F = 2→3 transition of the 87Rb D2 line at 780 nm, leading to a measured transition frequency of νRb = 384,228,115,346 ± 16 kHz. We performed the same measurement with a commercial fiber-laser comb operating in the 1.5-µm region. Both the OPO comb and the commercial fiber comb achieved similar performance. The measurement accuracy was limited by interferometric noise in the fibered setup of the Rb-stabilized laser.

[Sexual risk behaviour of nursing students. A cross-sectional study at nursing schools in Saxony-Anhalt]. / Das sexuelle Risikoverhalten von Auszubildenden der Gesundheits- und Krankenpflege. Eine Querschnittstudie an Krankenpflegeschulen in Sachsen-Anhalt.

AIM: This work describes the sexual risk behaviour of nursing students. METHODS: 22 of 23 state-approved nursing schools in Saxony-Anhalt, Germany, participated in this cross-sectional study (study period 7/2005-5/2006). Participation was voluntarily and anonymous. RESULTS: More male than female students (59.6% vs. 44.8%) used condoms to prevent STIs. More female students (58.9% vs. 43.4%) reported constant partnership with just one partner as an STI prevention method (chi² test, p<0.005). 29.6% of the nursing students reported >1 sexual partner in the past 12 months. 3.9% of the students demanded an HIV test from the partner, 69.3% had never tested themselves for HIV. 10.2% used no prevention against STIs. CONCLUSIONS: Nursing students should be sensitised for sexual risk behaviour and STIs. This should be included in the content of teaching throughout the education, not least since nursing students are multiplicators and have an influence on health behaviour of the patients.

Post-synthetic benzylation of the mRNA 5' cap via enzymatic cascade reactions.

mRNAs are emerging modalities for vaccination and protein replacement therapy. Increasing the amount of protein produced by stabilizing the transcript or enhancing translation without eliciting a strong immune response are major steps towards overcoming the present limitations and improving their therapeutic potential. The 5' cap is a hallmark of mRNAs and non-natural modifications can alter the properties of the entire transcript selectively. Here, we developed a versatile enzymatic cascade for regioselective benzylation of various biomolecules and applied it for post-synthetic modification of mRNA at the 5' cap to demonstrate its potential. Starting from six synthetic methionine analogues bearing (hetero-)benzyl groups, S-adenosyl-l-methionine analogues are formed and utilized for N7G-cap modification of mRNAs. This post-synthetic enzymatic modification exclusively modifies mRNAs at the terminal N7G, producing mRNAs with functional 5' caps. It avoids the wrong orientation of the 5' cap-a problem in common co-transcriptional capping. In the case of the 4-chlorobenzyl group, protein production was increased to 139% during in vitro translation and to 128-150% in four different cell lines. This 5' cap modification did not activate cytosolic pathogen recognition receptors TLR3, TLR7 or TLR8 significantly more than control mRNAs, underlining its potential to contribute to the development of future mRNA therapeutics.

Reference standard for serum bile acids in pregnancy.

OBJECTIVE: Obstetric cholestasis (OC) is a liver disorder characterised by pruritus and elevated serum bile acids (SBA) that affects one in 200 pregnant women. It is associated with adverse perinatal outcomes such as premature delivery and stillbirth. Mild OC is defined as SBA levels of 10-39 µmol/l, and severe OC is defined by levels >40 µmol/l. SBA levels in normal pregnancy have not been investigated. We aimed to establish reference values for SBA in healthy pregnant women across different trimesters of pregnancy. DESIGN: Cross-sectional analysis of SBA levels. SETTING: A large tertiary referral university teaching maternity hospital. POPULATION: Healthy pregnant women with a singleton pregnancy and a body mass index (BMI) < 40, excluding women with significant alcohol intake, history of liver disease, prior cholecystectomy and OC. METHODS: Cross-sectional analysis of SBA levels at 12, 20, 28 and 36 weeks of gestation, and on days 1-3 postpartum. MAIN OUTCOME MEASURES: SBA levels in µmol/l. RESULTS: A total of 219 women attending for antenatal care were recruited, and SBA levels were assayed at 12, 20, 28 and 36 weeks of gestation, and up to 72 hours postpartum (n = 44-49 cases at each stage). The majority were white European women, with a median age of 30 years (range 17-46 years) and median BMI of 25 (range 18-38). Values of SBA ranged from 0.3 to 9.8 µmol/l in 216 women, with only three measurements outside this range. There were no significant changes throughout pregnancy. CONCLUSIONS: SBA values in uncomplicated pregnancies are consistent, regardless of gestation, and are not elevated in pregnancy. The current reference values for the diagnosis of OC appear to be appropriate.

Maternal serum cholesterol levels are elevated from the 1st trimester of pregnancy: a cross-sectional study.

Cholesterol is monitored in the non-pregnant adult population, where normal values are established. Although reported to be elevated in pregnancy, cholesterol is neither routinely measured nor treated. We aimed to investigate cholesterol levels throughout pregnancy and to establish reference values for cholesterol in healthy pregnant women. This was a cross-sectional analysis of serum cholesterol in healthy women with an uncomplicated singleton pregnancy. Pregnant women attending for antenatal care were recruited and cholesterol levels assayed at 12, 20, 28 and 36 weeks' gestation and on day 1-3 postpartum. A total of 222 women were recruited. The majority (95%) were white Irish, with a median age of 31 years (range 16-46). Median BMI was 25.9 kg/m2 (range 18-40) and 16% were smokers. Cholesterol levels were elevated in all trimesters of pregnancy, with median values from 1st trimester raised outside the non-pregnant adult range. High-density lipoprotein (HDL) levels ranged from 0.9 to 3.7 mmol/l and low-density lipoprotein (LDL) levels ranged from 1.3 to 6.1 mmol/l. Fasting, smoking and obesity did not have any significant effects on results. Total and LDL-cholesterol levels were raised throughout pregnancy. Levels were above non-pregnant adult ranges as early as the 1st trimester. The implications of this on fetus and mother are undetermined and deserve further investigation.

Subharmonic resonant optical excitation of confined acoustic modes in a free-standing semiconductor membrane at GHz frequencies with a high-repetition-rate femtosecond laser.

We propose subharmonic resonant optical excitation with femtosecond lasers as a new method for the characterization of phononic and nanomechanical systems in the gigahertz to terahertz frequency range. This method is applied for the investigation of confined acoustic modes in a free-standing semiconductor membrane. By tuning the repetition rate of a femtosecond laser through a subharmonic of a mechanical resonance we amplify the mechanical amplitude, directly measure the linewidth with megahertz resolution, infer the lifetime of the coherently excited vibrational states, accurately determine the system's quality factor, and determine the amplitude of the mechanical motion with femtometer resolution.

High-speed asynchronous optical sampling with sub-50fs time resolution.

We report an ultrafast time-domain spectroscopy system based on high-speed asynchronous optical sampling operating without mechanical scanner. The system uses two 1 GHz femtosecond oscillators that are offset-stabilized using high-bandwidth feedback electronics operating at the tenth repetition rate harmonics. Definition of the offset frequency, i.e. the time-delay scan rate, in the range of a few kilohertz is accomplished using direct-digital-synthesis electronics for the first time. The time-resolution of the system over the full available 1 ns time-delay window is determined by the laser pulse duration and is 45 fs. This represents a three-fold improvement compared to previous approaches where timing jitter was the limiting factor. Two showcase experiments are presented to verify the high time-resolution and sensitivity of the system.

Terahertz emission from lateral photo-Dember currents.

The photo-Dember effect is a source of impulsive THz emission following femtosecond pulsed optical excitation. This emission results from the ultrafast spatial separation of electron-hole pairs in strong carrier gradients due to their different diffusion coefficients. The associated time dependent polarization is oriented perpendicular to the excited surface which is inaptly for efficient out coupling of THz radiation. We propose a scheme for generating strong carrier gradients parallel to the excited surface. The resulting photo-Dember currents are oriented in the same direction and emit THz radiation into the favorable direction perpendicular to the surface. This effect is demonstrated for GaAs and In(0.53)Ga(0.47)As. Surprisingly the photo-Dember THz emitters provide higher bandwidth than photoconductive emitters. Multiplexing of phase coherent photo-Dember currents by periodically tailoring the photoexcited spatial carrier distribution gives rise to a strongly enhanced THz emission, which reaches electric field amplitudes comparable to a high-efficiency externally biased photoconductive emitter.

Rapid-scanning terahertz precision spectrometer with more than 6 THz spectral coverage.

We report a terahertz time-domain spectrometer with more than 6 THz spectral coverage and 1 GHz resolution based on high-speed asynchronous optical sampling. It operates at 2 kHz scan rate without mechanical delay stage. The frequency error of the system at 60 s acquisition time is determined by comparing a measured water vapor absorption spectrum to data reported in the HITRAN database. The mean error of 87 evaluated absorption lines is 142 MHz.

Natural vision reveals regional specialization to local motion and to contrast-invariant, global flow in the human brain.

Visual changes in feature movies, like in real-live, can be partitioned into global flow due to self/camera motion, local/differential flow due to object motion, and residuals, for example, due to illumination changes. We correlated these measures with brain responses of human volunteers viewing movies in an fMRI scanner. Early visual areas responded only to residual changes, thus lacking responses to equally large motion-induced changes, consistent with predictive coding. Motion activated V5+ (MT+), V3A, medial posterior parietal cortex (mPPC) and, weakly, lateral occipital cortex (LOC). V5+ responded to local/differential motion and depended on visual contrast, whereas mPPC responded to global flow spanning the whole visual field and was contrast independent. mPPC thus codes for flow compatible with unbiased heading estimation in natural scenes and for the comparison of visual flow with nonretinal, multimodal motion cues in it or downstream. mPPC was functionally connected to anterior portions of V5+, whereas laterally neighboring putative homologue of lateral intraparietal area (LIP) connected with frontal eye fields. Our results demonstrate a progression of selectivity from local and contrast-dependent motion processing in V5+ toward global and contrast-independent motion processing in mPPC. The function, connectivity, and anatomical neighborhood of mPPC imply several parallels to monkey ventral intraparietal area (VIP).

1-GHz repetition rate femtosecond OPO with stabilized offset between signal and idler frequency combs.

We report an optical parametric oscillator (OPO) based on periodically poled lithium niobate (PPLN) that is synchronously pumped by a femtosecond Ti:sapphire laser at 1 GHz repetition rate. The signal output has a center wavelength of 1558 nm and its spectral bandwidth amounts to 40 nm. The OPO operates in a regime where the signal- and idler frequency combs exhibit a partial overlap around 1600 nm. In this near-degeneracy region, a beat at the offset between the signal and idler frequency combs is detected. Phase-locking this beat to an external reference stabilizes the spectral envelopes of the signal- and idler output. At the same time, the underlying frequency combs are stabilized relative to each other with an instability of 1.5x10(-17) at 1 s gate time.

Blood-brain barrier P-glycoprotein function is not impaired in early Parkinson's disease.

The cause of Parkinson's disease (PD) is unknown. Genetic susceptibility and exposure to environmental toxins contribute to specific neuronal loss in PD. Decreased blood-brain barrier (BBB) P-glycoprotein (P-gp) efflux function has been proposed as a possible causative link between toxin exposure and PD neurodegeneration. In the present study BBB P-gp function was investigated in vivo in 10 early stage PD patients and 8 healthy control subjects using (R)-[(11)C]-verapamil and PET. Cerebral volume of distribution (V(d)) of verapamil was used as measure of P-gp function. Both region of interest (ROI) analysis and voxel analysis using statistical parametric mapping (SPM) were performed to assess regional brain P-gp function. In addition, MDR1 genetic polymorphism was assessed. In the present study, a larger variation in V(d) of (R)-[(11)C]-verapamil was seen in the PD group as compared to the control group. However, decreased BBB P-gp function in early stage PD patients could not be confirmed.

OSIRIS-REx Contamination Control Strategy and Implementation.

OSIRIS-REx will return pristine samples of carbonaceous asteroid Bennu. This article describes how pristine was defined based on expectations of Bennu and on a realistic understanding of what is achievable with a constrained schedule and budget, and how that definition flowed to requirements and implementation. To return a pristine sample, the OSIRIS-REx spacecraft sampling hardware was maintained at level 100 A/2 and <180 ng/cm2 of amino acids and hydrazine on the sampler head through precision cleaning, control of materials, and vigilance. Contamination is further characterized via witness material exposed to the spacecraft assembly and testing environment as well as in space. This characterization provided knowledge of the expected background and will be used in conjunction with archived spacecraft components for comparison with the samples when they are delivered to Earth for analysis. Most of all, the cleanliness of the OSIRIS-REx spacecraft was achieved through communication among scientists, engineers, managers, and technicians.

Dosimetric evaluation of a 2D pixel ionization chamber for implementation in clinical routine.

In this paper we present the results of a dosimetric evaluation of a 2D ionization chamber array with the objective of its implementation for quality assurance in clinical routine. The pixel ionization chamber MatriXX (Scanditronix Wellhofer, Germany) consists of 32x32 chambers with a distance of 7.6 mm between chamber centres. The effective depth of measurement under the surface of the detector was determined. The dose and energy dependence, the behaviour of the device during its initial phase and its time stability as well as the lateral response of a single chamber of the detector in cross-plane and diagonal directions were analysed. It could be shown, that the detector's response is linear with dose and energy independent. Taking the lateral response into account, two different dose profiles, for a pyramidal and an IMRT dose distribution, were applied to compare the data generated by a treatment planning system with measurements. From these investigations it can be concluded that the detector is a suitable device for quality assurance and 2D dose verifications.

Ultrafast time-domain spectroscopy based on high-speed asynchronous optical sampling.

High-speed asynchronous optical sampling (ASOPS) is a novel technique for ultrafast time-domain spectroscopy (TDS). It employs two mode-locked femtosecond oscillators operating at a fixed repetition frequency difference as sources of pump and probe pulses. We present a system where the 1 GHz pulse repetition frequencies of two Ti:sapphire oscillators are linked at an offset of Deltaf(R)=10 kHz. As a result, their relative time delay is repetitively ramped from zero to 1 ns within a scan time of 100 micros. Mechanical delay scanners common to conventional TDS systems are eliminated, thus systematic errors due to beam pointing instabilities and spot size variations are avoided when long time delays are scanned. Owing to the multikilohertz scan-rate, high-speed ASOPS permits data acquisition speeds impossible with conventional schemes. Within only 1 s of data acquisition time, a signal resolution of 6 x 10(-7) is achieved for optical pump-probe spectroscopy over a time-delay window of 1 ns. When applied to terahertz TDS, the same acquisition time yields high-resolution terahertz spectra with 37 dB signal-to-noise ratio under nitrogen purging of the spectrometer. Spectra with 57 dB are obtained within 2 min. A new approach to perform the offset lock between the two femtosecond oscillators in a master-slave configuration using a frequency shifter at the third harmonic of the pulse repetition frequency is employed. This approach permits an unprecedented time-delay resolution of better than 160 fs. High-speed ASOPS provides the functionality of an all-optical oscilloscope with a bandwidth in excess of 3000 GHz and with 1 GHz frequency resolution.

Non-motor symptoms and quality of life in dopa-responsive dystonia patients.

BACKGROUND: In patients with GTP-cyclohydrolase deficient dopa-responsive dystonia (DRD) the occurrence of associated non-motor symptoms (NMS) is to be expected. Earlier studies report conflicting results with regard to the nature and severity of NMS. The aim of our study was to investigate the prevalence of psychiatric disorders, sleep problems, fatigue and health-related quality of life (HR-QoL) in a Dutch DRD cohort. METHODS: Clinical characteristics, motor symptoms, type and severity of psychiatric co-morbidity, sleep problems, fatigue and HR-QoL were assessed in DRD patients with a confirmed GCH1 mutation and matched controls. RESULTS: Twenty-eight patients were included (18 adults and 10 children), from 10 families. Dystonia symptoms were well-controlled in all patients. According to the DSM IV patients significantly more often met the criteria for a lifetime psychiatric disorder than controls (61% vs. 29%, p < 0.05). In particular the frequencies of generalized anxiety and agoraphobia were higher in patients (both 29% vs. 4%, p < 0.05). Patients scored significantly higher on daytime sleepiness than controls (ESS, 11.2 vs 5.7, p < 0.05). Adult patients had significantly lower scores on the mental component of the HR-QoL (47 vs. 54, p < 0.05) than controls mainly associated with (worse) quality of sleep. CONCLUSION: NMS were highly prevalent in our cohort of DRD patients, despite adequate treatment of motor symptoms. Our findings support the accumulating evidence of an important non-motor phenotype in DRD, with possible involvement of serotonergic mechanisms. This highlights the need to address NMS and the underlying neurobiology in patients with DRD.

A low-threshold self-referenced Ti:Sapphire optical frequency comb.

We demonstrate an octave-spanning, self-referenced optical frequency comb produced with a high-repetition-rate (frep=585 MHz) femtosecond Ti:Sapphire laser that requires less than 1 W of 532 nm pump power. The frequency comb was stabilized to a CW laser as required for optical clocks and low noise frequency synthesis. These results should be relevant for applications that require more-compact and efficient frequency combs.