Health Care Expenditure and Income: a Global Perspective

Abstrac

Efficiency implications of open source commonality and reuse

This paper analyzes the reuse choices made by open source developers and relates them to cost efficiency. We make a distinction between the commonality among applications and the actual reuse of code. The former represents the similarity between the requirements of different applications and, consequently, the functionalities that they provide. The latter represents the actual reuse of code. No application can be maintained for ever. A fundamental reason for the need for periodical replacement of code is the exponential growth of costs with the number of maintenance interventions. Intuitively, this is due to the increasing complexity of software that grows in both size and coupling among different modules. The paper measures commonality, reuse and development costs of 26 open-source projects for a total of 171 application versions. Results show that reuse choices in open-source contexts are not cost efficient. Developers tend to reuse code from the most recent version of applications, even if their requirements are closer to previous versions. Furthermore, the latest version of an application is always the one that has incurred the highest number of maintenance interventions. Accordingly, the development cost per new line of code is found to grow with reuse

Modeling brain connectivity dynamics in functional Magnetic Resonance Imaging via Particle Filtering

Interest in the studying of functional connections in the brain has grown considerably in the last decades, as many studies have pointed out that alterations in the interaction among brain areas can play a role as markers of neurological diseases. Most studies in this field treat the brain network as a system of connections stationary in time, but dynamic features of brain connectivity can provide useful information, both on physiology and pathological conditions of the brain. In this paper, we propose the application of a computational methodology, named Particle Filter (PF), to study non-stationarities in brain connectivity in functional Magnetic Resonance Imaging (fMRI). The PF algorithm estimates time-varying hidden parameters of a first-order linear time-varying Vector Autoregressive model (VAR) through a Sequential Monte Carlo strategy. On simulated time series, the PF approach effectively detected and enabled to follow time-varying hidden parameters and it captured causal relationships among signals. The method was also applied to real fMRI data, acquired in presence of periodic tactile or visual stimulations, in different sessions. On these data, the PF estimates were consistent with current knowledge on brain functioning. Most importantly, the approach enabled to detect statistically significant modulations in the cause-effect relationship between brain areas, which correlated with the underlying visual stimulation pattern presented during the acquisition

Gabapentin Bioequivalence Study: Quantification By Liquid Chromatography Coupled To Mass Spectrometry

The study was performed to compare the bioavailability of two gabapentin 400 mg capsule formulation (Gabapentin from Arrow Farmacêutica S/A as test formulation and Neurontin ® from Pfizer, Brazil, as reference formulation) in 26 volunteers of both sexes. The study was conducted open with randomized two period crossover design and a one week wash out period. Plasma samples were obtained over a 48 hour interval. The gabapentin was analyzed by LC/MS/MS, in the presence of pracetamole as internal standard. With plasma concentration vs. time curves, data obtained from this metabolite, the following pharmacokinetics parameters were obtained: AUC 0-t, AUC 0-inf and C max. Geometric mean of gabapentin/Neurontin ® 400 mg individual percent ratio was 100.58% AUC 0-t, 101.35% for AUC 0-inf and 97.76% for C max. The 90% confidence intervals were 92.00 - 109.95%, 93.00 - 110.44%, 88.41 - 108.10%, respectively. Since the 90% confidence intervals for C max, AUC 0-t and AUC 0 -inf were within the 80 - 125% interval proposed by Food and Drug Administration, it was concluded that gabapentin 400 mg capsule was bioequivalent to Neurontin ® 400 mg capsule according to both the rate and extent of absorption. © 2011 Junior EA, et al.38187190Wattananat, T., Akarawut, W., Validated LC-MS-MS Method for the Determination of Gabapentin in Human Plasma: Application to a Bioequivalence Study (2009) J Chromatogr Sci, 47, pp. 868-871Stewart, B.H., Kagler, A.R., Thompson, P.R., Bockbrader, H.N., A saturable transport mechanism in the intestinal absorption of gabapentin is the underlying cause of the lack of proportionality between increasing dose and drug levels in plasma (1993) Pharma Res, 10, pp. 276-281McLean, M.J., Gabapentin in the management of convulsive disorders (1999) Epilepsia, 40, pp. 39-50Goa, K.L., Sorkin, E.M., Gabapentin: A review of its pharmacological properties and clinical potential in epilepsy (1993) Drugs, 46, pp. 409-427Zhu, Z., Neirinck, L., High-performance liquid chromatographic method for the determination of gabapentin in human plasma (2002) J Chromatogr B Analyt Technol Biomed Life Sci, 779, pp. 307-312Sagirli, O., Cetin, S.M., Determination of gabapentin in human plasma and urine by high-performance liquid chromatography with UV-vis detection (2006) J Pharm Biomed Anal, 42, pp. 618-624Jalalizadeh, H., Souri, E., Tehrani, M.B., Jahangiri, A., Validated HPLC method for the determination of gabapentin in human plasma using precolumn derivatization with 1-fluoro-2,4-dinitrobenzene and its application to a pharmacokinetic study (2007) J Chromatogr B Analyt Technol Biomed Life Sci, 854, pp. 43-47Forrest, G., Sills, G.J., Leach, J.P., Brodie, M.J., Determination of gabapentin in plasma by high-performance liquid chromatography (1996) J Chromatogr B Analyt Technol Biomed Life Sci, 681, pp. 421-425Tang, P.H., Miles, M.V., Glauser, T.A., Degrauw, T., Automated microanalysis of gabapentin in human serum by high-performance liquid chromatography with fluorometric detection (1999) J Chromatogr B Analyt Technol Biomed Life Sci, 727, pp. 125-129Hassan, E.M., Belal, F., Al-Deeb, O.A., Khalil, N.Y., Spectrofluorimetric determination of vigabatrin and gabapentin in dosage forms and spiked plasma samples through derivatization with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (2001) J. AOAC Int., 84, pp. 1017-1024Gauthier, D., Gupta, R., Determination of gabapentin in plasma by liquid chromatography with fluorescence detection after solid-phase extraction with a C18 column (2002) Clin Chem, 48, pp. 2259-2261Chung, T.C., Tai, C.T., Wu, H.L., Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma (2006) J Chromatogr A, 119, pp. 294-298Bahrami, G., Kiani, A., Sensitive high-performance liquid chromatographic quantitation of gabapentin in human serum using liquid-liquid extraction and pre-column derivatization with 9-fluorenylmethyl chloroformate (2006) J Chromatogr B Analyt Technol Biomed Life Sci, 835, pp. 123-126Krivanek, P., Koppatz, K., Turnheim, K., Simultaneous isocratic HPLC determination of vigabatrin and gabapentin in human plasma by dansyl derivatization (2003) Ther Drug Monit, 25, pp. 374-377Chang, S.Y., Wang, F.Y., Simple and sensitive liquid chromatographic method with fluorimetric detection for the analysis of gabapentin in human plasma (2004) J Chromatogr B Analyt Technol Biomed Life Sci, 799, pp. 265-270Wolf, C.E., Saady, J.J., Poklis, A., Determination of gabapentin in serum using solid phase extraction and gas-liquid chromatography (1996) J Anal Toxicol, 20, pp. 498-501Kushnir, M.M., Cossett, J., Brown, P.I., Urry, F.M., Analysis of gabapentin in serum and plasma by solid-phase extraction and gas chromatography-mass spectrometry for therapeutic drug monitoring (1999) J Anal Toxicol, 23, pp. 1-6Borrey, D.C., Godderis, K.O., Engelrelst, V.I., Bernard, D.R., Langlois, M.R., Quantitative determination of vigabatrin and gabapentin in human serum by gas chromatography-mass spectrometry (2005) Clin Chim Acta, 354, pp. 147-151Gambelunghe, C., Mariucci, G., Tantucci, M., Ambrosini, M.V., Gas chromatography-tandemmass spectrometry analysis of gabapentin in serum (2005) Biomed Chromatogr, 19, pp. 63-67Matar, K.M., Abdel-Hamid, M.E., Rapid tandem mass spectrometric method for determination of gabapentin in human plasma (2005) Chromatographia, 61, pp. 499-504Ramakrishna, N.V.S., Vishwottam, K.N., Koteshwara, M., Maroj, S., Santosh, M., Rapid quantification of gabapentin in human plasma by liquid chromatography/tandemmass spectrometry (2006) J Pharm Biomed Anal, 40, pp. 360-368Ifa, D.R., Falci, M., Moraes, M.E., Bezerra, F.A., Moraes, M.O., Gabapentin quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry. Application to bioequivalence study (2001) J Mass Spectrom, 36, pp. 188-194Ji, H.Y., Jeong, D.W., Kim, Y.H., Kim, H.H., Yoon, Y.S., Determination of gabapentin in human plasma using hydrophilic interaction liquid chromatography with tandem mass spectrometry (2006) Rapid Commun Mass Spectrom, 20, pp. 2127-2132Carlsson, K.C., Reubsaet, J.L., Sample preparation and determination of gabapentin in venous and capillary blood using liquid chromatography-tandem mass spectrometry (2004) J Pharm Biomed Anal, 34, pp. 415-423Park, J.H., Jhee, O.H., Park, S.H., Lee, J.S., Lee, M.H., Validated LC-MS/ MS method for quantification of gabapentin in human plasma: Application to pharmacokinetic and bioequivalence studies in Korean volunteers (2007) Biomed Chromatogr, 21, pp. 829-83

Double-Tuned Birdcage Radio Frequency Coil for 7 T MRI: Optimization, Construction and Workbench Validation

The aim of the present study is the optimization, construction, and workbench validation of a double-tuned 1H- 23Na volume radio frequency (RF) coil suitable for human head imaging at 7 T, based on the birdcage geometry. The birdcage-like design which is considered is the four-ring model, in which two standard birdcage-like structures with the same diameters are nested along the longitudinal axis. Simulations based on Maxwell’s equations are performed to evaluate the RF magnetic field homogeneity and the RF coil efficiency varying the coil geometrical parameters. The RF magnetic field homogeneity is evaluated both on the transverse (z = 0) and longitudinal (y = 0) planes without performing the impedance matching procedure, so that the RF coil symmetry is not perturbed by the matching network. The RF coil efficiency is instead dependent on the effective coil input RF power, and it is evaluated after matching the coil, so that the reflected power is minimized, assuming that the stimulation power is totally delivered to the RF coil. Considering the simulation results and the target application, the useful RF coil geometrical parameters are fixed. The four-ring model, which showed the best performances, has been built and tested on a workbench, using a cylindrical phantom filled with a 0.05 M saline solution as load. This provides the first example of a four-ring realization intended 1H- 23Na for human head imaging at 7 T

Semiautomated Evaluation of the Primary Motor Cortex in Patients with Amyotrophic Lateral Sclerosis at 3T

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Semiautomated evaluation of the primary motor cortex in patients with amyotrophic lateral sclerosis at 3t

Amyotrophic lateral sclerosis is a neurodegenerative disease involving the upper and lower motor neurons. In amyotrophic lateral sclerosis, pathologic changes in the primary motor cortex include Betz cell depletion and the presence of reactive iron-loaded microglia, detectable on 7T MR images as atrophy and T2*-hypointensity. Our purposes were the following: 1) to investigate the signal hypointensity-to-thickness ratio of the primary motor cortex as a radiologic marker of upper motor neuron involvement in amyotrophic lateral sclerosis with a semiautomated method at 3T, 2) to compare 3T and 7T results, and 3) to evaluate whether semiautomated measurement outperforms visual image assessment

The impact of air pollution on hospital admissions: Evidence from Italy

In this paper we study the impact of air pollution on hospital admissions for chronic obstructive pulmonary disease for 103 Italian provinces, over the period from 2004 to 2009. We use information on annual mean concentrations of carbon monoxide, nitrogen dioxide, particulate matter, and ozone measured at monitoring station level to build province-level indicators of pollution. Hence, we estimate a regression model for hospital admissions, where we allow our aggregate measures of pollution to be subject to measurement error and correlated with the error term. We also adopt standard errors for estimates that are robust to serial and spatial correlation in the error term, to allow for temporal persistence and geographical concentration of unobservable risk factors.We find that higher levels of particulate matter are associated with higher levels of hospitalisation for children, while ozone plays an important role in explaining hospital admissions of the elderly. Other factors that appear to have an effect on hospital admissions for chronic obstructive pulmonary disease are precipitation and provincial unemployment rate

A systematic review and meta-analysis on oncological radiotherapy in patients with a cardiac implantable electronic device: Prevalence and predictors of device malfunction in 3121 patients

Background: The number of patients with cardiac implantable electronic devices (CIEDs) undergoing radiotherapy (RT) for cancer treatment is growing. At present, prevalence and predictors of RT-induced CIEDs malfunctions are not defined. Methods: Systematic review and meta-analysis conducted following the PRISMA recommendations. PubMed, Scopus and Google Scholar were searched from inception to 31/01/2022 for studies reporting RT-induced malfunctions in CIEDs patients. Aim was to assess the prevalence of RT-induced CIEDs malfunctions and identify potential predictors. Results: Thirty-two out of 3962 records matched the inclusion criteria and were included in the meta-analysis. A total of 135 CIEDs malfunctions were detected among 3121 patients (6.6%, 95% confidence interval [CI]: 5.1%–8.4%). The pooled prevalence increased moving from pacemaker (PM) to implantable cardioverter defibrillator (ICD), and cardiac resynchronization therapy and defibrillator (CRT-D) groups (4.1%, 95% CI: 2.9–5.8; 8.2% 95% CI: 5.9–11.3; and 19.8%, 95% CI: 11.4–32.2 respectively). A higher risk ratio (RR) of malfunctions was found when neutron-producing energies were used as compared to non-neutron-producing energies (RR 9.98, 95% CI: 5.09–19.60) and in patients with ICD/CRT-D as compared to patients with PM/CRT-P (RR 2.07, 95% CI: 1.40–3.06). On the contrary, no association was found between maximal radiation dose at CIED >2 Gy and CIEDs malfunctions (RR 0.93; 95% CI: 0.31–2.76). Conclusions: Radiotherapy related CIEDs malfunction had a prevalence ranging from 4% to 20%. The use of neutron-producing energies and more complex devices (ICD/CRT-D) were associated with higher risk of device malfunction, while the radiation dose at CIED did not significantly impact on the risk unless higher doses (>10 Gy) were used