759 research outputs found
Calibration of the Neutral Mass Spectrometer for the Lunar Atmosphere and Dust Environment Explorer
Science objectives of the LADEE Mission are to (1) determine the composition, and time variability of the tenuous lunar atmosphere and (2) to characterize the dust environment and its variability. These studies will extend the in-situ characterization of the environment that were carried out decades ago with the Apollo missions and a variety of ground based studies. The focused LADEE measurements will enable a more complete understanding of dust and gas sources and sinks. Sources of gas include UV photo-stimulated desorption, sputtering by plasma and micrometeorites, as well as thermal release of species such as argon from the cold service or venting from the lunar interior. Sinks include recondensation on the surface and escape through a variety of mechanisms. The LADEE science payload consists of an Ultraviolet Spectrometer, a Neutral Mass Spectrometer, and a Dust Detector. The LADEE orbit will include multiple passes at or below 50 km altitude and will target repeated sampling at the sunrise terminator where exospheric density will be highest for some thermally released species. The science mission will be implemented in approximately three months to allow measurements to be made over a period of one or more lunations In addition to the science mission NASA will use this mission to demonstrate optical communication technology away from low Earth orbit
Paper and electronic versions of HM-PRO, a novel patient-reported outcome measure for hematology: an equivalence study.
© 2019 Goswami, Oliva, Ionova et al.Aim:To determine measurement equivalence of paper and electronic application of the hematologi-cal malignancy-patient-reported outcome (HM-PRO), a specific measure for the evaluation of patient-reported outcomes in HMs.Patients & methods:Following International Society of Pharmacoeconomicsand Outcomes Research ePRO Good Research Practice Task Force guidelines, a total of 193 adult patientswith different HMs were recruited into a multicenter prospective study. The paper and the electronic ver-sion of the instrument were completed in the outpatient clinics in a randomized crossover design with a30-min time interval to minimize the learning effect. Those who completed the paper version first, com-pleted the electronic version after 30 min and vice versa. Instrument version and order effects were testedon total score of the two parts of the HM-PRO (Part A: quality of life and Part B: signs & symptoms) in atwo-way ANOVA with patients as random effects. Intraclass correlation coefficients (95% CI) and Spear-man’s rank correlation coefficients were used to evaluate test–retest reliability and reproducibility. Theeffects of instrument version and order were tested on total score of the two parts of HM-PRO.Results:The questionnaire version and administration order effects were not significant at the 5% level. Therewere no interactions found between these two factors for HM-PRO (Part A [quality of life]; p=0.95); and(part B [signs and symptoms]; p=0.72]. Spearman’s rank correlation coefficients were greater than 0.9, andintraclass correlation coefficients ranged from 0.94 to 0.98; furthermore, the scores were not statisticallydifferent between the two versions, showing acceptable reliability indexes. Noteworthy, the differencebetween the completion time for both paper (mean=6:38 min) and electronic version (mean=7:29 min)was not statistically significant (n=100; p=0.11). Patients did not report any difficulty in completing theelectronic version during cognitive interviews and were able to understand and respond spontaneously.Conclusion:Measurement equivalence has been demonstrated for the paper and electronic applicationof the HM-PRO.Peer reviewe
Exact diagonalization of the S=1/2 Heisenberg antiferromagnet on finite bcc lattices to estimate properties on the infinite lattice
Here we generate finite bipartite body-centred cubic lattices up to 32
vertices. We have studied the spin one half Heisenberg antiferromagnet by
diagonalizing its Hamiltonian on each of the finite lattices and hence
computing its ground state properties. By extrapolation of these data we obtain
estimates of the T = 0 properties on the infinite bcc lattice. Our estimate of
the T = 0 energy agrees to five parts in ten thousand with third order spin
wave and series expansion method estimates, while our estimate of the staggered
magnetization agrees with the spin wave estimate to within a quarter of one
percent.Comment: 16 pages, LaTeX, 1 ps figure, to appear in J.Phys.
Understanding key parameters affecting needle-free skin penetration by a parenteral drug delivery system
This thesis seeks to resolve difficulties in the development of a parenteral needle-free drug delivery
system. Analysis of the penetration performance of Glide Pharma’s Solid Dose Injector in two
clinical trials on man has shown that skin, and likely its inherent variation, was the cause
of incomplete deliveries. As indicated by the literature and issues with previous needle-free
technologies, a more complete understanding of skin penetration is required before such systems
are capable of ensuring delivery across a patient population.
Exploratory skin experiments led to the justification, design and build of a novel skin penetration
test rig capable of simulating the delivery of a solid dose implant. This test rig, the Penetrometer,
required significant software development to both stabilise and validate its performance before
use on the in vivo porcine model, an established non-clinical model for drug delivery through
human skin.
Two non-clinical studies have been performed using the Penetrometer to capture force displacement
profiles, using a metal probe equivalent to an implant, for penetration events on multiple
test sites on multiple models. Significant levels of variation in key parameters were shown to
be present intra- and inter-test site, as well as intra- and inter-model. It is likely that this
variation, as detected in the porcine model, was the cause of problematic system performance
during human clinical trials. Penetration experiments have also been performed to establish the
validity of using in vitro skin or silicone rubber as an alternative test bed to in vivo models.
The key parameters measured are the peak force during penetration, the displacement of the
skin at penetration and the work required to penetrate the skin, with variations observed of the
order of 30%, 100% and 140%, respectively. The results indicate how challenging it will be to
reliably administer drugs using needle-free injection. This information should be used to better
specify the device design and implant formulation to ensure delivery success.
Prior to this thesis there was no quantitative data available, either published or within the
collaborator, describing the magnitude and variation of the key parameters affecting needle-free
skin penetration. This thesis has used the porcine model, further work must determine the
parameters for the breadth of a human patient population
Evaluation of Pulse Counting for the Mars Organic Mass Analyzer (MOMA) Ion Trap Detection Scheme
The Mars Organic Mass Analyzer is being developed at Goddard Space Flight Center to identify organics and possible biological compounds on Mars. In the process of characterizing mass spectrometer size, weight, and power consumption, the use of pulse counting was considered for ion detection. Pulse counting has advantages over analog-mode amplification of the electron multiplier signal. Some advantages are reduced size of electronic components, low power consumption, ability to remotely characterize detector performance, and avoidance of analog circuit noise. The use of pulse counting as a detection method with ion trap instruments is relatively rare. However, with the recent development of high performance electrical components, this detection method is quite suitable and can demonstrate significant advantages over analog methods. Methods A prototype quadrupole ion trap mass spectrometer with an internal electron ionization source was used as a test setup to develop and evaluate the pulse-counting method. The anode signal from the electron multiplier was preamplified. The an1plified signal was fed into a fast comparator for pulse-level discrimination. The output of the comparator was fed directly into a Xilinx FPGA development board. Verilog HDL software was written to bin the counts at user-selectable intervals. This system was able to count pulses at rates in the GHz range. The stored ion count nun1ber per bin was transferred to custom ion trap control software. Pulse-counting mass spectra were compared with mass spectra obtained using the standard analog-mode ion detection. Prelin1inary Data Preliminary mass spectra have been obtained for both analog mode and pulse-counting mode under several sets of instrument operating conditions. Comparison of the spectra revealed better peak shapes for pulse-counting mode. Noise levels are as good as, or better than, analog-mode detection noise levels. To artificially force ion pile-up conditions, the ion trap was overfilled and ions were ejected at very high scan rates. Pile-up of ions was not significant for the ion trap under investigation even though the ions are ejected in so-called 'ion-micro packets'. It was found that pulse counting mode had higher dynamic range than analog mode, and that the first amplification stage in analog mode can distort mass peaks. The inherent speed of the pulse counting method also proved to be beneficial to ion trap operation and ion ejection characterization. Very high scan rates were possible with pulse counting since the digital circuitry response time is so much smaller than with the analog method. Careful investigation of the pulse-counting data also allowed observation of the applied resonant ejection frequency during mass analysis. Ejection of ion micro packets could be clearly observed in the binned data. A second oscillation frequency, much lower than the secular frequency, was also observed. Such an effect was earlier attributed to the oscillation of the total plasma cloud in the ion trap. While the components used to implement pulse counting are quite advanced, due to their prevalence in consumer electronics, the cost of this detection system is no more than that of an analog mode system. Total pulse-counting detection system electronics cost is under $25
Calibration of the Quadrupole Mass Spectrometer of the Sample Analysis at Mars Instrument Suite
The SAM suite of instruments on the "Curiosity" Rover of the Mars Science Laboratory (MSL) is designed to provide chemical and isotopic analysis of organic and inorganic volatiles for both atmospheric and solid samples. The mission of the MSL investigations is to advance beyond the successful search for aqueous transformation in surface environments at Mars toward a quantitative assessment of habitability and preservation through a series of chemical and geological measurements. The SAM suite was delivered in December 2010 (Figure 1) to the Jet Propulsion Laboratory for integration into the Curiosity Rover. We previously outlined the range of SAM solid and gas calibrations implemented or planned and here we discuss a specific set of calibration experiments to establish the response of the SAM Quadrupole Mass Spectrometer (QMS) to the four most abundant gases in the Martian atmosphere CO2, N2, Ar, and O2, A full SAM instrument description and calibration report is presently in preparation
The Influence of Race/Ethnicity, Gender, Age, Social Support, Religion/Spirituality, and Occupational History on the Total Wellness of Counseling Practicum Graduate Students: A Pilot Study
This study sought to identify and explore the differences in participants’ Total Wellness scores with respect to race/ethnicity, gender, age, social support, spirituality, and occupational history. It was asserted that there would be observable differences in the delineated demographic research factors and that these differences would influence students’ Total Wellness as measured by the 5F-Wel Inventory. The sample was comprised of 30 graduate students enrolled in a community mental health counseling program. Hierarchal linear regression indicated that demographic variables did not predict a change in Total Wellness when controlling for pretest scores; however, pretest Total Wellness scores were significantly predictive of post-test Total Wellness scores. Implications for counseling practice and clinical supervision, suggestions for integrating wellness into counseling education, as well as areas for future research including replication and expansion of the current study are offered
Optimism and Planning for Future Care Needs Among Older Adults
Aging is associated with an increase in need for assistance. Preparation for future care (PFC) is related to improved coping ability as well as better mental and physical health outcomes among older adults. We examined the association of optimism with components of PFC among older adults. We also explored race differences in the relationship between optimism and PFC. In Study 1, multiple regression showed that optimism was positively related to concrete planning. In Study 2, optimism was related to gathering information. An exploratory analysis combining the samples yielded a race interaction: For Whites higher optimism, but for Blacks lower optimism was associated with more planning. High optimism may be a barrier to future planning in certain social and cultural contexts
Functional Impairment, Illness Burden, and Depressive Symptoms in Older Adults: Does Type of Social Relationship Matter?
Objective: The nature of interpersonal relationships, whether supportive or critical, may affect the association between health status and mental health outcomes. We examined the potential moderating effects of social support, as a buffer, and family criticism, as an exacerbating factor, on the association between illness burden, functional impairment and depressive symptoms.
Methods: Our sample of 735 older adults, 65 years and older, was recruited from internal and family medicine primary care offices. Trained interviewers administered the Hamilton Rating Scale for Depression, Duke Social Support Inventory, and Family Emotional Involvement and Criticism Scale. Physician-rated assessments of health, including the Karnofsky Performance Status Scale and Cumulative Illness Rating Scale, were also completed.
Results: Linear multivariable hierarchical regression results indicate that social interaction was a significant buffer, weakening the association between illness burden and depressive symptoms, whereas perceived social support buffered the relationship between functional impairment and depressive symptoms. Family criticism and instrumental social support were not significant moderators.
Conclusions: Type of medical dysfunction, whether illness or impairment, may require different therapeutic and supportive approaches. Enhancement of perceived social support, for those who are impaired, and encouragement of social interactions, for those who are ill, may be important intervention targets for treatment of depressive symptoms in older adult primary care patients
Overcoming the translational challenges of the effective administration and delivery of cells
Of the few cell-based therapies widely available today the most mature are the treatment of blood-borne cancers and wound healing. The routes of administration for these applications are well understood and a great deal of research has resolved the many biological, pharmacological and engineering challenges associated with the delivery of cells by these methods.
These delivery methods are only suitable for a small proportion of the possible cell therapies. Many other treatments under development for illnesses that affect organs – such as diabetes, dermatological conditions and degenerative diseases – require more complex tools and methods to ensure cells are efficiently and effectively delivered to structures such as the pancreas, skin and brain. Injuries to musculoskeletal tissues such as cartilage, intra-vertebral disc and bone may be more easily accessed; however, they present different challenges, as the delivery methods must not reduce the long-term mechanical function of the tissue the treatment is attempting to repair.
Oversights can occur due to the reliance on existing and often unsuitable pre-clinical models for delivery and experimental methods and data that cannot be readily translated into the clinic. Different cell types and their behaviours will also lead to complications, so too will engineering challenges such as dosing accuracy, delivery to the appropriate site, engraftment and cell viability after shear and thermal stresses.
The delivery method and device used should be considered a crucial part of the cell therapy as a whole. Many companies in regenerative medicine have designed their own delivery device often in series, not in parallel, with the development of their product. As more treatments get closer to clinic many more different devices will be required, thus presenting opportunities for those who understand the generic delivery challenges in the field
- …
