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Mycorrhizas of six spruces of a stand were collected over two years and were analysed for soluble carbohydrates (sucrose, raffinose, glucose, trehalose and mannitol). The level of these carbohydrates was high during winter and low during summer. Upon exposure of excised mycorrhizas to frost or desiccation, the content of trehalose roughly doubled. A positive correlation was found between the trehalose content of mycorrhizas and their ability to survive frost or desiccation as determined by the electrolyte leaching method. [ABSTRACT FROM AUTHOR]

Objectives: Telephone instructions are commonly used to improve cardiopulmonary resuscitation (CPR) by lay bystanders. This usually implies an audio but no visual connection between the provider and the emergency medical telecommunicator. We aimed to investigate whether video-guided feedback via a camera drone enhances the quality of CPR., Methods: We conducted a randomized controlled simulation trial. Lay rescuers performed 8 min of CPR on an objective feedback manikin. Participants were randomized to receive telephone instructions with (intervention group) or without (control group) a drone providing a visual connection with the telecommunicator after a 2-min run-in phase. Performed work (total compression depth minus total lean depth) was the primary outcome. Secondary outcomes were the proportion of effective chest compressions, average compression depth, subjective physical strain measured every 2 min, and dexterity in the nine-hole peg test after the scenario. Outcomes were compared using the t - and Mann Whitney- U tests. A two-sided p -value of <0.05 was considered significant., Results: We included 27 individuals (14 (52%) female, mean age 41 ± 14 years). Performed work was greater in the intervention than in the control group (41.3 ± 7.0 vs. 33.9 ± 10.9 m; absolute difference 7.5, 95% CI 1.4 to 14.8; p  = 0.046), with higher average compression depth (49 ± 7 vs. 40 ± 13 mm; p  = 0.041), and higher proportions of adequate chest compressions (43 (IQR 14-60) vs. 3 (0-29) %; p  = 0.041). We did not find any significant differences regarding the remaining secondary outcomes., Conclusion: Video-guided feedback via drones might be a helpful tool to enhance the quality of telephone-assisted CPR in lay bystanders.

Background: Performing cardiopulmonary resuscitation (CPR) inevitably causes significant physical, as well as psychological stress for rescuers. Physical activity at high altitude, a hypobaric and hypoxic environment, similarly adds to the level of stress and causes multiple physiological changes. Continuous measurement of pulse rate serves as an objective measure of fatigue during CPR. We therefore aimed to investigate rescuers' heart rates as a measure of physical strain during CPR in a high-altitude alpine environment to provide a better understanding of the physiological changes under these very special conditions., Methods: Twenty experienced mountaineers performed basic life support (BLS) on a manikin for 16 min, both at baseline altitude and at high altitude (3454 m) following a quick and exhausting ascent over 1200 m. Sequence of scenarios was randomised for analysis. Heart rate was continuously measured and compared between baseline and high altitude by absolute differences and robust confidence intervals., Results: During CPR at baseline, the average heart rate increased from 87 bpm (SD 16 bpm) to 104 bpm [increase 17 bpm (95% CI 8.24-24.76)], compared to an increase from 119 bpm (SD 12 bpm) to 124 bpm [increase 5 bpm (95% CI - 1.59 to 12.19)] at high altitude [difference between two groups 32 bpm (95% CI 25-39)]. Differences between periods of chest compressions and ventilations were very similar at baseline [19 bpm (95%CI 16.98-20.27)] and at high altitude [20 bpm 95% CI 18.56-21.44)], despite starting from a much higher level at high altitude. The average heart rates of rescuers at high altitude at any point were higher than those at baseline at any other point., Conclusion: Performing BLS CPR causes exhaustion both at base level and at a high altitude. A further increase during CPR might imply a physiological reserve for adapting to additional physical exertion at high altitude. Phases of ventilation are much needed recovery-periods, but heart rates remain very high. Subjective measures of exhaustion, such as the BORG-scale, might lead to rescuers' overestimation of their own performance., (© 2023. Norwegian Air Ambulance Foundation.)

Competing Interests: Declaration of competing interest We wish to confirm that there are no known conflicts of interest associated with this publication.

Competing Interests: Conflicts of interest: None.

Background: Treatment of acute traumatic pain is a core task for mountain rescue services. Intravenous access, however, is often difficult, and the vast majority of missions are carried out without a physician at the scene. The spectrum of analgesics available for use by non-physician personnel is limited. Inhaled analgesics, such as methoxyflurane, might prove useful, but currently no data exist on their application by non-physicians in the alpine setting. Methods: This prospective observational alpine field study was conducted over a period of 15 months. Patients suffering traumatic injuries with moderate to severe pain (pain score ≥ 5) after downhill bike accidents in the Tyrol mountains (1,362 m to 2,666 m above sea level) were enrolled. Teams of four mountain rescue service members, one of them a trained EMT, treated the patients with 3 ml of methoxyflurane by inhaler. We measured efficacy as reduction in pain from baseline to 15 minutes after treatment on a numerical rating scale. Safety was assessed by change in vital signs or occurrence of side-effects. Sample-size calculations were based on the efficacy outcome and yielded a need for 20 patients at a power of 0.8. Results: From June 29, 2020 to September 30, 2021, a total of 20 patients (two females; mean age 37 years) were included. The mean initial pain score was 7.2 (SD 1.0) points. After 15 minutes, pain was significantly reduced by a mean of 2.9 (SD 1.4) points. No major adverse events or relevant changes in vital signs were observed. Conclusion: The use of methoxyflurane by EMTs during alpine rescue operations in our study proved to be safe and efficient. We observed no reduction in the efficacy of the inhaler device at moderate altitude.

Background: The COVID-19 pandemic led to widespread use of personal protection equipment (PPE), including filtering face piece (FFP) masks, throughout the world. PPE. Previous studies indicate that PPE impairs neurocognitive performance in healthcare workers. Concerns for personnel safety have led to special recommendations regarding basic life support (BLS) in patients with a potential SARS-CoV-2 infection, including the use of PPE. Established instruments are available to assess attention and dexterity in BLS settings, respectively. We aimed to evaluate the influence of PPE with different types of FFP masks on these two neuropsychological components of EMS personnel during BLS., Methods: This was a randomized controlled non-inferiority triple-crossover study. Teams of paramedics completed three 12-min long BLS scenarios on a manikin after having climbed three flights of stairs with equipment, each in three experimental conditions: (a) without pandemic PPE, (b) with PPE including a FFP2 mask with an expiration valve and (c) with PPE including an FFP2 mask without an expiration valve. The teams and intervention sequences were randomized. We measured the shift in concentration performance using the d2 test and dexterity using the nine-hole peg test (NHPT). We compared results between the three conditions. For the primary outcome, the non-inferiority margin was set at 20 points., Results: Forty-eight paramedics participated. Concentration performance was significantly better after each scenario, with no differences noted between groups: d2 shift control versus with valve - 8.3 (95% CI - 19.4 to 2.7) points; control versus without valve - 8.5 (- 19.7 to 2.7) points; with valve versus without valve 0.1 (- 11.1 to 11.3) points. Similar results were found for the NHPT: + 0.3 (- 0.7 to 1.4), - 0.4 (- 1.4 to 0.7), 0.7 (- 0.4 to 1.8) s respectively., Conclusion: Attention increases when performing BLS. Attention and dexterity are not inferior when wearing PPE, including FFP2 masks. PPE should be used on a low-threshold basis., (© 2022. The Author(s).)

With conformation-specific nanobodies being used for a wide range of structural, biochemical, and cell biological applications, there is a demand for antigen-binding fragments (Fabs) that specifically and tightly bind these nanobodies without disturbing the nanobody-target protein interaction. Here, we describe the development of a synthetic Fab (termed NabFab) that binds the scaffold of an alpaca-derived nanobody with picomolar affinity. We demonstrate that upon complementary-determining region grafting onto this parent nanobody scaffold, nanobodies recognizing diverse target proteins and derived from llama or camel can cross-react with NabFab without loss of affinity. Using NabFab as a fiducial and size enhancer (50 kDa), we determined the high-resolution cryogenic electron microscopy (cryo-EM) structures of nanobody-bound VcNorM and ScaDMT, both small membrane proteins of ∼50 kDa. Using an additional anti-Fab nanobody further facilitated reliable initial three-dimensional structure determination from small cryo-EM test datasets. Given that NabFab is of synthetic origin, is humanized, and can be conveniently expressed in Escherichia coli in large amounts, it may be useful not only for structural biology but also for biomedical applications., Competing Interests: The authors declare no competing interests.

Aim: Prior studies suggest that the use of personal protective equipment might impair the quality of critical care. We investigated the influence of personal protective equipment on out-of-hospital cardiopulmonary resuscitation., Methods: Randomised controlled non-inferiority triple-crossover study. Forty-eight emergency medical service providers, randomized into teams of two, performed 12 min of basic life support (BLS) on a manikin after climbing 3 flights of stairs. Three scenarios were completed in a randomised order: Without personal protective equipment, with personal protective equipment including a filtering face piece (FFP) 2 mask with valve, and with personal protective equipment including an FFP2 mask without valve. The primary outcome was mean depth of chest compressions with a pre-defined non-inferiority margin of 3.5 mm. Secondary outcomes included other measurements of CPR quality, providers' subjective exhaustion levels, and providers' vital signs, including end-tidal CO 2 ., Results: Differences regarding the primary outcome were well below the pre-defined non-inferiority margins for both control vs. personal protective equipment without valve (absolute difference 1 mm, 95% CI [-1, 2]) and control vs. personal protective equipment with valve (absolute difference 1 mm, [-0.2, 2]). This was also true for secondary outcomes regarding quality of chest compressions and providers' vital signs including etCO 2 . Subjective physical strain after BLS was higher in the personal protective equipment groups (Borg 4 (SD 3) without valve, 4 (SD 2) with valve) than in the control group (Borg 3 (SD 2))., Conclusion: PPE including masks with and without expiration valve is safe for use without concerns regarding the impairment of CPR quality., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: High quality cardiopulmonary resuscitation is a key factor in survival with good overall quality of life after out-of-hospital cardiac arrest. Current evidence is predominantly based on studies conducted at low altitude, and do not take into account the special circumstances of alpine rescue missions. We therefore aimed to investigate the influence of physical strain at high altitude on the quality of cardiopulmonary resuscitation., Methods: Alpine field study. Twenty experienced mountaineers of the Austrian Mountain Rescue Service trained in Basic Life Support (BLS) performed BLS on a manikin in groups of two for 16 min. The scenario was executed at baseline altitude and immediately after a quick ascent over an altitude difference of 1200 m at 3454 m above sea level. The sequence of scenarios was randomised for a cross over analysis. Quality of CPR and exhaustion of participants (vital signs, Borg-Scale, Nine hole peg test) were measured and compared between high altitude and baseline using random-effects linear regression models., Results: The primary outcome of chest compression depth significantly decreased at high altitude compared to baseline by 1 cm (95% CI 0.5 to 1.3 cm, p < 0.01). There was a significant reduction in the proportion of chest compressions in the target depth (at least 5 cm pressure depth) by 55% (95% CI 29 to 82%, p < 0.01) and in the duration of the release phase by 75 ms (95% CI 48 to 101 ms, p < 0.01). No significant difference was found regarding hands-off times, compression frequency or exhaustion., Conclusion: Physical strain during a realistic alpine rescue mission scenario at high altitude led to a significant reduction in quality of resuscitation. Resuscitation guidelines developed at sea level are not directly applicable in the mountain terrain.