Abstract
Background and purpose
Subsequent to the health problems of the acute phase of SARS-CoV-2 infection, the long-term consequences of SARS-CoV-2 infection are affecting large numbers of ...patients worldwide. To date, no evidence-based treatment is available for the increasing number of patients with persisting symptoms post COVID 19 infection. We hypothesized that physical exercise may represent a safe and effective treatment option post COVID.
Methods
We performed a systematic search of the literature that revealed a lack of randomized training studies in patients post COVID. Based on these findings a prospective randomized controlled study with open-label and blinded endpoint evaluation was designed. 272 patients with symptoms of fatigue persisting over 6 weeks post COVID infection were screened. Patients with cardiovascular findings were excluded. 44 patients consented and were randomized to four weeks of supervised personalized strength endurance training for 4 weeks or usual care (Fig.1). The mean age was 42.7±13.4 years, and 61% were females.
Results
The individualized combined training was very well tolerated by the participants and the exercise compliance (quality of training) was high at 96.7 ± 2.0 %. There were no adverse events related to the training. Spirometric analysis showed a significantly higher increase in VO2peak (exercise: 10.0±12.7% vs. control: 0.1±8.9%, p<0.01) and oxygen-pulse (exercise: 9.8±10.8% vs. control: 0.0±13.9%, p<0.05) indicating the training effects of the intervention (Fig.2). Parameters of the Multidimensional Fatigue inventory-20 (MFI-20), the McGill Quality of Life Questionnaire (MQOL), and the Post-COVID-19 Functional Status (PCFS) were significantly improved after 4 weeks in both groups. The improvements in fatigue and quality of life were not statistically different between the training and usual care groups.
Conclusion
An individualized exercise program is a safe and well-tolerated treatment option in patients with persisting symptoms post-Covid. These patients significantly improve in physical performance after 4 weeks compared to patients without exercise intervention. Fatigue and quality of life improve over time in individuals that are willing to participate in a training study irrespective of allocation to the training group.Fig. 1:Flow diagram of the inclusion process in the PCTS studyFig. 2:Changes in relative oxygen uptake, oxygen pulse, and MFI-20 of the exercise and the control group between T0: baseline visit and T1: after exercise intervention or after the corresponding period in the control group. The red line represents the mean.*: p<0.05; **: p<0.01 ***: p<0.001, ***: p<0.0001, #: p<0.05 percentual change between groups.
In this work we present a keV-scale sterile-neutrino search with a low-tritium-activity data set of the KATRIN experiment, acquired in a commissioning run in 2018. KATRIN performs a spectroscopic ...measurement of the tritium
β
-decay spectrum with the main goal of directly determining the effective electron anti-neutrino mass. During this commissioning phase a lower tritium activity facilitated the measurement of a wider part of the tritium spectrum and thus the search for sterile neutrinos with a mass of up to
1.6
keV
. We do not find a signal and set an exclusion limit on the sterile-to-active mixing amplitude of
sin
2
θ
<
5
×
10
-
4
(
95
%
C.L.) at a mass of 0.3 keV. This result improves current laboratory-based bounds in the sterile-neutrino mass range between 0.1 and 1.0 keV.
The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at - 18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise ...high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two Formula omittedKr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN's commissioning measurements in July 2017. The measured scale factor Formula omitted of the high-voltage divider K35 is in agreement with the last PTB calibration 4 years ago. This result demonstrates the utility of the calibration method, as well as the long-term stability of the voltage divider.
The KATRIN experiment is designed for a direct and model-independent determination of the effective electron anti-neutrino mass via a high-precision measurement of the tritium
β
-decay endpoint ...region with a sensitivity on
m
ν
of 0.2
eV
/
c
2
(90% CL). For this purpose, the
β
-electrons from a high-luminosity windowless gaseous tritium source traversing an electrostatic retarding spectrometer are counted to obtain an integral spectrum around the endpoint energy of 18.6 keV. A dominant systematic effect of the response of the experimental setup is the energy loss of
β
-electrons from elastic and inelastic scattering off tritium molecules within the source. We determined the energy-loss function in-situ with a pulsed angular-selective and monoenergetic photoelectron source at various tritium-source densities. The data was recorded in integral and differential modes; the latter was achieved by using a novel time-of-flight technique. We developed a semi-empirical parametrization for the energy-loss function for the scattering of 18.6-keV electrons from hydrogen isotopologs. This model was fit to measurement data with a 95%
T
2
gas mixture at 30 K, as used in the first KATRIN neutrino-mass analyses, as well as a
D
2
gas mixture of 96% purity used in KATRIN commissioning runs. The achieved precision on the energy-loss function has abated the corresponding uncertainty of
σ
(
m
ν
2
)
<
10
-
2
eV
2
1
in the KATRIN neutrino-mass measurement to a subdominant level.
In this work we present a keV-scale sterile-neutrino search with a low-tritium-activity data set of the KATRIN experiment, acquired in a commissioning run in 2018. KATRIN performs a spectroscopic ...measurement of the tritium β-decay spectrum with the main goal of directly determining the effective electron anti-neutrino mass. During this commissioning phase a lower tritium activity facilitated the measurement of a wider part of the tritium spectrum and thus the search for sterile neutrinos with a mass of up to 1.6 keV. We do not find a signal and set an exclusion limit on the sterile-to-active mixing amplitude of $\text {sin}^{2}\: \theta<5\times 10^{-4}\: (95\%\: $C.L) at a mass of 0.3 keV. This result improves current laboratory-based bounds in the sterile-neutrino mass range between 0.1 and 1.0 keV.
The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to make a model-independent determination of the effective electron antineutrino mass with a sensitivity of 0.2 eV/c2. It investigates the ...kinematics of β-particles from tritium β-decay close to the endpoint of the energy spectrum. Because the KATRIN main spectrometer (MS) is located above ground, muon-induced backgrounds are of particular concern. Coincidence measurements with the MS and a scintillator-based muon detector system confirmed the model of secondary electron production by cosmic-ray muons inside the MS. Correlation measurements with the same setup showed that about 12% of secondary electrons emitted from the inner surface are induced by cosmic-ray muons, with approximately one secondary electron produced for every 17 muon crossings. However, the magnetic and electrostatic shielding of the MS is able to efficiently suppress these electrons, and we find that muons are responsible for less than 17% (90% confidence level) of the overall MS background.
The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)-neutrino mass with a sensitivity of 0.2eV/c
2
by precisely measuring the endpoint region of the ...tritium
β
-decay spectrum. It uses a tandem of electrostatic spectrometers working as magnetic adiabatic collimation combined with an electrostatic (MAC-E) filters. In the space between the pre-spectrometer and the main spectrometer, creating a Penning trap is unavoidable when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create additional background electrons and endanger the spectrometer and detector section downstream. To counteract this problem, “electron catchers” were installed in the beamline inside the magnet bore between the two spectrometers. These catchers can be moved across the magnetic-flux tube and intercept on a sub-ms time scale the stored electrons along their magnetron motion paths. In this paper, we report on the design and the successful commissioning of the electron catchers and present results on their efficiency in reducing the experimental background.
The KATRIN experiment aims to measure the effective electron antineutrino mass
m
ν
¯
e
with a sensitivity of
0.2
eV
/
c
2
using a gaseous tritium source combined with the MAC-E filter technique. A ...low background rate is crucial to achieving the proposed sensitivity, and dedicated measurements have been performed to study possible sources of background electrons. In this work, we test the hypothesis that gamma radiation from external radioactive sources significantly increases the rate of background events created in the main spectrometer (MS) and observed in the focal-plane detector. Using detailed simulations of the gamma flux in the experimental hall, combined with a series of experimental tests that artificially increased or decreased the local gamma flux to the MS, we set an upper limit of
0.006
count
/
s
(90% C.L.) from this mechanism. Our results indicate the effectiveness of the electrostatic and magnetic shielding used to block secondary electrons emitted from the inner surface of the MS.
Aim
Postoperative drains have historically been used for the prevention and early detection of intra‐abdominal collections. However, current evidence suggests that prophylactic drain placement ...following colorectal surgery has no significant clinical benefit. This is reflected in the enhanced recovery after surgery (ERAS) guidelines, which recommend against their routine use. The Ileus Management International study found more than one‐third of participating centres across the world routinely used drains in the majority of colorectal resections. The aim of the present study is to audit international compliance with ERAS guidelines regarding the use of postoperative drains in colorectal surgery.
Method
This prospective, multicentre audit will be conducted via the student‐ and trainee‐led EuroSurg Collaborative network across Europe, South Africa and Australasia. Data will be collected on consecutive patients undergoing elective and emergency colorectal surgery with 30‐day follow‐up. This will include any colorectal resection, formation of colostomy/ileostomy and reversal of stoma. The primary end‐point will be adherence to ERAS guidelines for intra‐abdominal drain placement. Secondary outcomes will include the following: time to diagnosis of intra‐abdominal postoperative collections; output and time to removal of drains; and 30‐day postoperative complications defined by the Clavien–Dindo classification.
Conclusion
This protocol describes the methodology for the first international audit of intra‐abdominal drain placement after colorectal surgery. The study will be conducted across a large collaborative network with quality assurance and data validation strategies. This will provide a clear understanding of current practice and novel evidence regarding the efficacy and safety of intra‐abdominal drain placement in colorectal surgical patients.
The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)-neutrino mass with a sensitivity of 0.2eV/c \(^2\) by precisely measuring the endpoint region of the ...tritium \(\beta \) -decay spectrum. It uses a tandem of electrostatic spectrometers working as magnetic adiabatic collimation combined with an electrostatic (MAC-E) filters. In the space between the pre-spectrometer and the main spectrometer, creating a Penning trap is unavoidable when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create additional background electrons and endanger the spectrometer and detector section downstream. To counteract this problem, “electron catchers” were installed in the beamline inside the magnet bore between the two spectrometers. These catchers can be moved across the magnetic-flux tube and intercept on a sub-ms time scale the stored electrons along their magnetron motion paths. In this paper, we report on the design and the successful commissioning of the electron catchers and present results on their efficiency in reducing the experimental background.
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