[National Immunisation Programme: is vaccinating less an option?] / Rijksvaccinatieprogramma: is minder vaccineren een optie?

Many people are no longer familiar with the diseases that are part of the Dutch National Immunisation Programme (NIP). The protection given by the NIP has ensured that these diseases, most of them serious, have largely disappeared. The NIP has developed gradually, but in retrospect it was in 1957 that what we now know as the NIP started. Over the years, the NIP has gradually expanded to include various vaccines such as live attenuated vaccines, conjugate vaccines and vaccines that offer protection against chronic viral infections. Currently, the NIP offers protection against twelve different diseases. Occasionally the Netherlands still sees minor outbreaks of those diseases included in the NIP programme, generally among non-vaccinated people. It is important that the NIP is retained; stopping vaccination always leads to the return of the disease. The question is: can good protection be maintained with fewer injections? This subject is on the agenda of the Health Council Of The Netherlands for discussion in 2022.

Prevention of tick bites: an evaluation of a smartphone app.

BACKGROUND: Lyme borreliosis (LB) is the most common reported tick-borne infection in Europe, and involves transmission of Borrelia by ticks. As long as a vaccine is not available and effective measures for controlling tick populations are insufficient, LB control is focused on preventive measures to avoid tick bites. To inform citizens about the risk of ticks, motivate them to check for tick bites, and encourage them to remove any attached tick as quickly as possible, a mobile app called 'Tekenbeet' (Dutch for 'tick bite') was developed and released. The aim of this study was to evaluate the usage and user satisfaction of the 'Tekenbeet' app and to investigate whether it affects users' knowledge, perceived severity, perceived susceptibility, self-efficacy, response efficacy, current behavior and intention to comply with preventive measures. METHODS: Usage of the app was evaluated with data obtained from Google Analytics. A survey among the Dutch general adult population with two data collection periods evaluated the usage, user satisfaction and its influence on abovementioned outcomes. RESULTS: Data obtained from Google Analytics showed the app was downloaded almost 40,000 in the 20 months following the launch. The 'tick radar' and 'tick diary' screens were viewed most often. In addition, a total of 554 respondents completed an online survey. The mean user satisfaction score was 7.44 (on a scale of 1-10) and 90.9% of respondents would recommend the app to others. On average, survey respondents who downloaded the app (n = 243) recorded significantly more often higher knowledge scores (OR 3.37; 95% CI 2.02-5.09) and had a higher intention to comply with preventive measures (OR 2.47; 95% CI 1.22-5.85) compared to respondents who did not download the app (n = 311). CONCLUSIONS: The 'Tekenbeet' app is a frequently used and well-appreciated educational tool to increase public knowledge of ticks and tick bites. It also helps to improve the user's intention to apply preventive measures. The use of smartphones and apps is now commonplace in the Netherlands; the 'Tekenbeet' app feeds into this trend and thereby offers a modern day alternative to established formats such as an information leaflet and information provision on the Internet.

Ponderomotive manipulation of cold subwavelength plasmas.

Ponderomotive forces (PFs) induced in cold subwavelength plasmas by an externally applied electromagnetic wave are studied analytically. To this end, the plasma is modeled as a sphere with a radially varying permittivity, and the internal electric fields are calculated by solving the macroscopic Maxwell equations using an expansion in Debye potentials. It is found that the PF is directed opposite to the plasma density gradient, similarly to large-scale plasmas. In the case of a uniform density profile, a residual spherically symmetric compressive PF is found, suggesting possibilities for contactless ponderomotive manipulation of homogeneous subwavelength objects. The presence of a surface PF on discontinuous plasma boundaries is derived. This force is essential for a microscopic description of the radiation-plasma interaction consistent with momentum conservation. It is shown that the PF integrated over the plasma volume is equivalent to the radiation pressure exerted on the plasma by the incident wave. The concept of radiative acceleration of subwavelength plasmas, proposed earlier, is applied to ultracold plasmas. It is estimated that these plasmas may be accelerated to keV ion energies, resulting in a neutralized beam with a brightness comparable to that of current high-performance ion sources.

Three-dimensional flow in electromagnetically driven shallow two-layer fluids.

Recent experiments on a freely evolving dipolar vortex in a homogeneous shallow fluid layer have clearly shown the existence and evolution of complex three-dimensional (3D) flow structures. The present contribution focuses on the 3D structures of a dipolar vortex evolving in a stable shallow two-layer fluid. Experimentally, Stereoscopic Particle Image Velocimetry is used to measure instantaneously all three components of the velocity field in a horizontal plane and 3D numerical simulations provide the full 3D velocity and vorticity fields over the entire flow domain. Remarkably, the experimental results, supported by the numerical simulations, show to a large extent the same 3D structures and evolution as in the single-layer case. The numerical simulations indicate that the so-called frontal circulation in the two-layer fluid is due to deformations of the internal interface. The 3D flow structures will also affect the distribution of massless passive particles released at the free surface. With numerical studies it is shown that these passive particles tend to accumulate or deplete locally where the horizontal velocity field is not divergence-free. This is in contrast with pure two-dimensional incompressible flows where the divergence of the velocity field is zero by definition.

Io volcanism seen by new horizons: a major eruption of the Tvashtar volcano.

Jupiter's moon Io is known to host active volcanoes. In February and March 2007, the New Horizons spacecraft obtained a global snapshot of Io's volcanism. A 350-kilometer-high volcanic plume was seen to emanate from the Tvashtar volcano (62 degrees N, 122 degrees W), and its motion was observed. The plume's morphology and dynamics support nonballistic models of large Io plumes and also suggest that most visible plume particles condensed within the plume rather than being ejected from the source. In images taken in Jupiter eclipse, nonthermal visible-wavelength emission was seen from individual volcanoes near Io's sub-Jupiter and anti-Jupiter points. Near-infrared emission from the brightest volcanoes indicates minimum magma temperatures in the 1150- to 1335-kelvin range, consistent with basaltic composition.

Bunch self-focusing regime of laser wakefield acceleration with reduced emittance growth.

A new regime of laser wakefield acceleration of an injected electron bunch is described. In this regime, the bunch charge is so high that the bunch wakefields play an important role in the bunch dynamics. In particular, the transverse bunch wakefield induces a strong self-focusing that suppresses the transverse emittance growth arising from misalignment errors. The decelerating longitudinal bunch wakefield, however, is not so strong that it completely cancels the accelerating laser wakefield. In fact, the induced energy spread can be compensated by exploiting phase slippage effects. These features make the new regime interesting for high beam quality laser wakefield acceleration.

Generation of fast electrons by breaking of a laser-induced plasma wave.

A one-dimensional model for fast electron generation by an intense, nonevolving laser pulse propagating through an underdense plasma has been developed. Plasma wave breaking is considered to be the dominant mechanism behind this process, and wave breaking both in front of and behind the laser pulse is discussed. Fast electrons emerge as a short bunch, and the electrostatic field of this bunch is shown to limit self-consistently the amount of generated fast electrons.

Simulation of laser wakefield acceleration of an ultrashort electron bunch.

The dynamics of the acceleration of a short electron bunch in a strong plasma wave excited by a laser pulse in a plasma channel is studied both analytically and numerically in slab geometry. In our simulations, a fully nonlinear, relativistic hydrodynamic description for the plasma wave is combined with particle-in-cell methods for the description of the bunch. Collective self-interactions within the bunch are fully taken into account. The existence of adiabatic invariants of motion is shown to have important implications for the final beam quality. Similar to the one-dimensional case, the natural evolution of the bunch is shown to lead, under proper initial conditions, to a minimum in the relative energy spread.

How goal disturbance, coping and chest pain relate to quality of life: A study among patients waiting for PTCA.

This article describes psychological correlates of quality of life (QOL) in patients on a waiting list for percutaneous transluminal coronary angioplasty (PTCA). Variables were selected based on a theoretical model describing psychological correlates of QOL in PTCA patients. This model was based on self-regulation and stress-coping theories. The variables in the model are stress appraisal, coping, coping resources, and general and disease-specific QOL variables. Respondents were 122 patients on a 3-month waiting list for a PTCA. Results indicated that PTCA patients had a poorer QOL than matched healthy controls. Using a path analysis approach to regression analysis, it appeared that goal disturbance, avoidant coping, approach coping, and chest pain were related to QOL. More specifically, chest pain and goal disturbance were only related to health-related QOL and negative affect. Both approach and avoidant coping were related to QOL variables. Results could be explained adequately using self-regulation theory. Recommendations for future research and for form and content of rehabilitation programmes were made.

Cognitive status and relocation stress: a test of the vulnerability hypothesis.

PURPOSE: This study investigated whether cognitively impaired nursing home residents are at particular risk of experiencing harmful effects during a mass, intra-institutional, interbuilding relocation. DESIGN AND METHODS: A pretest-post-test experimental-comparison group design was used. Data on cognitive status, functional capacity, psychosocial health status, physical health status, and mortality were abstracted from the Minimum Data Set Plus and were analyzed using continuous and discrete survival analyses, controlling for covariates as well as baseline status of outcome variables. RESULTS: None of the Relocation x Cognitive Status interaction effects were significant. Relocation main effects indicated that movers in general were more likely than nonmovers to decline in physical health status. Evidence also emerged for a positive long-term effect of moving on psychosocial health status. IMPLICATIONS: These findings suggest cognitively impaired residents are not at unusual risk of harmful effects as a consequence of mass, interbuilding transfer. Given the significant relocation main effects, though, caution must be taken in moving cognitively impaired residents, as it should be in moving any residents.

False-positive findings in mammography screening induces short-term distress - breast cancer-specific concern prevails longer.

The aim of this study was to examine psychological distress in a mammography screening process as a consequence of screening after adjusting for background, personality and prescreening distress. Subjects, aged 50 years, were invitees at their first screening. There were three groups; normal findings (n=1407), false-positive findings (n=492) and referents from outside the screening programme (n=1718, age 48-49 years). Distress was measured as illness worry, anxiety, depression, cancer beliefs and early detection behaviour. Measurements were one month before screening invitation with follow-ups at 2 and 12 months postscreening. At 2 months, there was a moderate multivariate effect of group on distress; and intrusive thinking and worry about breast cancer, in particular, were most frequent amongst the false positives. Intrusive thinking still prevailed at 12 months, in addition to a higher perceived breast cancer risk and susceptibility. Distress related to screening and false-positive findings seems to be moderate, but prevailing cancer-specific concerns call for improvements in screening programmes.

A close-up look at Io from Galileo's near-infrared mapping spectrometer.

Infrared spectral images of Jupiter's volcanic moon Io, acquired during the October and November 1999 and February 2000 flybys of the Galileo spacecraft, were used to study the thermal structure and sulfur dioxide distribution of active volcanoes. Loki Patera, the solar system's most powerful known volcano, exhibits large expanses of dark, cooling lava on its caldera floor. Prometheus, the site of long-lived plume activity, has two major areas of thermal emission, which support ideas of plume migration. Sulfur dioxide deposits were mapped at local scales and show a more complex relationship to surface colors than previously thought, indicating the presence of other sulfur compounds.

Proximate humid and dry regions in Jupiter's atmosphere indicate complex local meteorology.

Models of Jupiter's formation and structure predict that its atmosphere is enriched in oxygen, relative to the Sun, and that consequently water clouds should be present globally near the 5-bar pressure level. Past attempts to confirm these predictions have led to contradictory results; in particular, the Galileo probe revealed a very dry atmosphere at the entry site, with no significant clouds at depths exceeding the 2-bar level. Although the entry site was known to be relatively cloud-free, the contrast between the observed local dryness and the expected global wetness was surprising. Here we analyse near-infrared (around 5 microm) observations of Jupiter, a spectral region that can reveal the water vapour abundance and vertical cloud structure in the troposphere. We find that humid and extremely dry regions exist in close proximity, and that some humid regions are spatially correlated with bright convective clouds extending from the deep water clouds to the visible atmosphere.

Effect of different barriers of oxidized regenerated cellulose (ORC) on cecal and sidewall adhesions in the presence and absence of bleeding.

Adhesion formation after bowel surgery is a significant problem. The objective of this study was to evaluate two adhesion barriers composed of oxidized regenerated cellulose (ORC) in a model of bowel surgery, with and without bleeding. Ceca of female New Zealand White rabbits were abraded with gauze and a 3 x 5 cm patch of peritoneum and underlying muscle was excised from the right sidewall. Animals were randomized to receive no treatment, INTERCEED Barrier (Ethicon, Inc.), or neutralized INTERCEED (nTC7). ORC fabrics were applied to the excision site. Seven days later the percentage of the site and length of cecum with adhesions were estimated. The study was replicated in the presence of blood by nicking small vessels near the site sufficient to saturate the fabrics with blood. With hemostasis, the percentage of the sidewall with adhesions was reduced (p < .01) from 63.2 +/- 14.7% in controls (n = 6) to 4 +/- 2.7% with INTERCEED Barrier (n = 6) and 3 +/- 1.2% (n = 5) with nTC7. With bleeding, however, control (n = 5) levels of adhesions (67 +/- 17.5%) were reduced significantly with nTC7 (5.5 +/- 4%, n = 4; p < .01), but not INTERCEED Barrier (34.2 +/- 18.4%, n = 4). Similar trends were observed when the extent of adherent cecum was examined, since the cecum was the main site of adherence to the sidewall. However in the presence of blood, there was no effect of INTERCEED Barrier on cecal adhesions. We conclude that with hemostasis, both absorbable fabrics of ORC reduced adhesion formation between the injured cecum and abdominal sidewall. The effectiveness of INTERCEED Barrier, but not nTC7, was reduced but not eliminated in the presence of bleeding. This confirms similar observations in models of gynecologic surgery.

The complex association of pulmonary function with panic disorder: a rejoinder to Ley (1998).

In a commentary on our paper entitled "Pulmonary function in panic disorder: evidence against the dyspnea-fear theory", Ley (1998) provides a critical analysis of our study. He concludes that our failed attempt to replicate a relationship between pulmonary function and the severity of panic-related symptoms in panic disorder patients may have been a consequence of a lack of comparability between studies, a statistical anomaly, and experimenter-demand effects. After discussing his comments (with most of them we do not agree) in depth, we maintain our conclusion that: (a) pulmonary impairment is not directly associated with panic symptoms; and (b) that the existence of a distinct subgroup of panic disorder patients with signs of actual airways obstruction leading to uncontrollable dyspnea and fear of suffocation remains questionable.

Near-infrared spectroscopy and spectral mapping of Jupiter and the Galilean satellites: results from Galileo's initial orbit.

The Near Infrared Mapping Spectrometer performed spectral studies of Jupiter and the Galilean satellites during the June 1996 perijove pass of the Galileo spacecraft. Spectra for a 5-micrometer hot spot on Jupiter are consistent with the absence of a significant water cloud above 8 bars and with a depletion of water compared to that predicted for solar composition, corroborating results from the Galileo probe. Great Red Spot (GRS) spectral images show that parts of this feature extend upward to 240 millibars, although considerable altitude-dependent structure is found within it. A ring of dense clouds surrounds the GRS and is lower than it by 3 to 7 kilometers. Spectra of Callisto and Ganymede reveal a feature at 4. 25 micrometers, attributed to the presence of hydrated minerals or possibly carbon dioxide on their surfaces. Spectra of Europa's high latitudes imply that fine-grained water frost overlies larger grains. Several active volcanic regions were found on Io, with temperatures of 420 to 620 kelvin and projected areas of 5 to 70 square kilometers.

Fibrinolytic drugs prevent pericardial adhesions in the rabbit.

Epicardial adhesions are believed to form secondarily to impaired pericardial fibrinolytic activity. This activity was reconstituted in a rabbit pericardial adhesion model with single doses of the fibrinolytic agents tissue plasminogen activator (t-PA), t-PA analog (Fb-Fb-CF), and streptokinase (SK), resulting in reductions in the extent and tenacity of adhesion formation. Adhesions of the median strip of the anterior cardiac surface were reduced in area from 89% (n = 22) in controls, to 28% (n = 5) by treatment with Fb-Fb-CF (0.94 mg), and to 49% (n = 7) by treatment with SK (93,750 IU). A modified fabric of oxidized regenerated cellulose (mTC7) used to deliver the agent to the cardiac surface did not interfere with the activity of these agents (Fb-Fb-CF 19%, n = 14; SK 33%, n = 7). t-PA (0.94 mg) was also found to reduce adhesion formation in combination with mTC7 (4%, n = 4), although the appearance of significant postoperative bruising and bleeding resulted in a decision to terminate the treatment of further animals with t-PA with and without mTC7. Postoperative bruising, bleeding, and swelling, to a lesser extent, were associated with SK and Fb-Fb-CF. Despite the efficacy of the these fibrinolytic drugs further work is required to assess their safety before they are used clinically.

Galileo infrared imaging spectroscopy measurements at venus.

During the 1990 Galileo Venus flyby, the Near Infaied Mapping Spectrometer investigated the night-side atmosphere of Venus in the spectral range 0.7 to 5.2 micrometers. Multispectral images at high spatial resolution indicate substanmial cloud opacity variations in the lower cloud levels, centered at 50 kilometers altitude. Zonal and meridional winds were derived for this level and are consistent with motion of the upper branch of a Hadley cell. Northern and southern hemisphere clouds appear to be markedly different. Spectral profiles were used to derive lower atmosphere abundances of water vapor and other species.

Synergistic effects of INTERCEED(TC7) and heparin in reducing adhesion formation in the rabbit uterine horn model.

Surgical adjuvants are commonly employed to reduce the frequency of postoperative adhesion development after reproductive pelvic surgery. The ability of indomethacin, promethazine dexamethasone, Intralipid, progesterone, and heparin to reduce adhesion formation in combination with INTERCEED(TC7) (Johnson and Johnson Medical, Inc., New Brunswick, NJ), an absorbable barrier that alone reduces adhesion formation, was examined in a rabbit uterine horn model. A significant reduction in adhesion formation was only observed with the combination of INTERCEED(TC7) plus heparin. In addition studies, heparin delivery by intraperitoneal (IP) lavage, intravenous injection, or intra-abdominal instillation failed to demonstrate efficacy. Similarly, heparin delivery with other barriers or IP instillates (carboxymethylcellulose or 32% Dextran 70) failed to reduce adhesion formation. We conclude that INTERCEED(TC7) can be efficaciously utilized as a carrier to deliver heparin to traumatized surfaces, thereby reducing adhesion formation.