[Topicality of the fundamental and determining importance of chronic critical ischemia of the extremities and its restorative treatment using crural/pedal bypasses in Germany and in Saxony-Anhalt]

INTRODUCTION

Currently, there is an increase in severe stages of peripheral arterial occlusive disease (PAOD) with critical ischemia. This seems to correspond to the general demographic change as well as a consequence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic of the last 3 years. The now established and accepted interventional/endovascular approach for severe lower leg PAOD in experienced hands is still considered the first-line treatment but from the authors' perspective crural/pedal venous bypass is experiencing a renaissance.

MATERIAL AND METHODS

Compact narrative review of the current state of crural/pedal bypass surgery in Germany and Saxony-Anhalt (SA) combined with selective references from the current scientific medical literature and own clinical experiences.

RESULTS

The current statistics of case-related diagnosis-related groups (DRG) data show that, especially with the occurrence of the corona pandemic, a decrease in inpatient case numbers of patients with PAOD stage IIB can be observed nationwide and also in SA. The severe PAOD stages have remained approximately the same in case numbers but increased in SA. The risk stratification based on the wound, ischemia and foot infection (WIFI) classification offers the possibility to be able to make statements about the risk of amputation, benefits and type of revascularization measures. The length of the occlusion, occlusion site of the affected vessels and degree of calcification are taken into account in the global limb anatomic staging system (GLASS) to assess the prognosis. The evaluation of the case-based hospital statistics from 2015 to 2020 showed a constant use of femorocrural/femoropedal bypass surgery in Germany as well as a slight increase in reconstruction using femorocrural bypasses in SA, which seems to correlate with the tendency for an increase in the number of cases of severe PAOD. Parameter-based objectification of the severity of critical limb ischemia should be included in the indications for placement of a crural/pedal bypass. The WIFI classification and GLASS are suitable for this purpose as a relative prognosis of success is also possible. The treatment of critical limb ischemia by crural/pedal bypass surgery continues to find a constant application in Germany and SA.

[Statutory provisions, aims, motives, attitudes and thinking on the outpatient operation profile of general and abdominal surgery]

AIM

The aim of the manuscript is to discuss and assess the implications and opportunities as well as dangers of "outpatientization" of surgical and inpatient services for general and abdominal surgery.

METHOD

Narrative overview with literature reference based on a PubMed search with the search terms: outpatient operations and inpatient interventions, AOP catalog, hybrid DRG, outpatient hernia surgery, outpatient proctological surgery, selective sector-equal reimbursement and day-care forms of care. RESULTS (KEY POINTS): - In the Anglo-American area, the treatment of inguinal hernias is predominantly carried out on an outpatient clinic basis. In the USA, Sweden and Denmark, for example, over 70% of all hernias are treated in an outpatient clinic setting, in Germany it is only 20%. In Germany, the catalog of operations that can be performed on an outpatient basis and other department-replacing interventions in hospitals defines outpatient interventions in accordance with § 115b Social Security Code (SGB) V (Germany). - The conversion from inpatient to outpatient hernia surgery has also failed so far due to an enormous difference in revenues. According to the will of the Federal Ministry of Health, the planned forms of semistationary care are intended to relieve the nursing staff in the hospitals and thus relieve the tense situation of nursing professionals. By the end of March 2023, a special industry-specific reimbursement, so-called hybrid DRGs, is to be agreed, which applies regardless of whether a paid service is provided on an outpatient or inpatient basis. - According to § 115b SGB V, whether a hernia can be performed under inpatient or outpatient conditions is also decided according to the location of the hernia. In the new AOP catalog, frailty is operationalized in the context factors via the degree of care and the Barthel index. If one compares the number of encryption procedures for the 5‑530 procedure (closure of an inguinal hernia) in 2005 (184,679) with the pre-corona year 2019 (179,851), it can be seen that the proportion of hernias treated in hospital remained approximately the same over a period of 14 years. - Most elective proctological procedures can be performed on an outpatient basis. For reasons of safety (bleeding) and practicality (pain management, dressing change of large abscesses), inpatient surgery is preferred: extensive hemorrhoidectomy in the case of massive findings, large abscesses, extensive perianal fistula corrections, particularly high transsphincteric or suprasphincteric fistulas. - Guidelines based on the British Guidelines for Ambulant Surgery should be required for comprehensive outpatient treatment in surgery. The introduction of corresponding hybrid DRGs seems to be the right way to cover the costs of outpatient surgery in hospitals.

CONCLUSION

The restructuring of the hospital landscape and the nationwide expansion of outpatient operations is an unavoidable requirement in view of rising costs in the healthcare system and impending financing bottlenecks, which will pose challenges for the surgical disciplines in the years to come. Outpatient surgery is already practiced in many areas but has not become established due to the different remuneration. The flat rates for the same branches can be a starting point here. Furthermore, evidence-based framework conditions must be created along the lines of the British Guidelines for Ambulant Surgery.

The effect of an abdominal binder on postoperative outcome after open incisional hernia repair in sublay technique: a multicenter, randomized pilot trial (ABIHR-II)

INTRODUCTION

Although the evidence is minimal, an abdominal binder is commonly prescribed after open incisional hernia repair (IHR) to reduce pain. This study aimed to investigate this common postoperative treatment.

METHODS

The ABIHR-II trial was a national prospective, randomized, multicenter non-AMG/MPG pilot study with two groups of patients (wearing an abdominal binder (AB) for 2 weeks during daytime vs. not wearing an AB following open IHR with the sublay technique). Patient enrollment took place from July 2020 to February 2022. The primary endpoint was pain at rest on the 14th postoperative day (POD) using the visual analog scale (VAS). The use of analgesics was not systematically recorded. Mixed-effects linear regression models were used.

RESULTS

A total of 51 individuals were recruited (25 women, 26 men; mean age 61.4 years; mean body mass index 30.65 kg/m2). The per-protocol analysis included 40 cases (AB group, n = 21; No-AB group, n = 19). Neither group showed a significant difference in terms of pain at rest, limited mobility, general well-being, and seroma formation and rate. Patients among the AB group had a significantly lower rate of surgical site infection (SSI) on the 14th POD (AB group 4.8% (n = 1) vs. No-AB group 27.8% (n = 5), p = 0.004).

CONCLUSION

Wearing an AB did not have an impact on pain and seroma formation rate but it may reduce the rate of postoperative SSI within the first 14 days after surgery. Further trials are mandatory to confirm these findings.

[Lack of experienced surgeons in vascular surgery-A joint task]

INTRODUCTION

An increasing shortage of specialists and training assistants is also being lamented in vascular surgery. Despite a continuous increase in the number of physicians and medical students in Germany in recent years, the need for specialists and training assistants in vascular surgery is enormous in a sustained manner.

METHODS

Professional policy analysis from a medical vascular surgery perspective including currently available statistics, especially from the Federal Statistical Office, the Federal Medical Association, the Saxony-Anhalt (SA) State Medical Association and selective references from current medical scientific literature on epidemiological topics.

RESULTS

In 2022, according to the basic data of the Federal Statistical Office 200 vascular surgery departments provided a total of 5706 beds for care. In 2021, 1574 physicians with the regional and specialist title in vascular surgery were registered by the medical associations. In the following years, there was an increase of 404 vascular surgeons. The recognition of the specialist title for vascular surgery fell from 166 in 2018 to 143 in 2021. There are 23 vascular surgery care units in Saxony-Anhalt (SA). At the SA Medical Association, there were 52 registered doctors with the specialist title in vascular surgery in the inpatient sector in 2021. In comparison, at the North Rhine Medical Association in 2021 there were 362 registered doctors with regional and specialist titles in vascular surgery overall and 292 in the inpatient sector. The age-standardized hospital incidence of peripheral arterial occlusive disease (PAOD) rose from approximately 190 to over 250 per 100,000 inhabitants in Germany between 2005 and 2016 and plateaued at this level. This corresponded to a relative increase of 33%. During the same observational period, the number of procedures performed doubled, mainly due to a strong increase in the number of endovascular interventions (approximately 140% increase) and interventions for arterial embolism/thrombosis (approximately + 80%). A research report commissioned by the German Hospital Society (DKG) in 2010 predicted a replacement requirement for physicians of approximately 108,000 by 2019 and an additional requirement of almost 31,000 physicians. While 14.6-27.2% of those employed in 2008 will have retired by 2020, between 45.6% and 68.5% will retire by 2030. Despite the statistically verifiable improvement in the staffing situation of specialists in vascular surgery in the inpatient and outpatient sectors in Germany, it can be assumed that there is a problem in recruiting young specialists. In order to target the recruitment of junior staff, it is first necessary to comprehensively record basic data on the staff situation and staff development in the area of residents in vascular surgery. In addition, further work should be done on implementing the recommendations for action already put forward years ago by scientific reports at state and federal levels.

Manifestation of acute appendicitis as known but paradox visceral side effect of ulcerative colitis anti-inflammatory therapy with januskinase-inhibitor Tofacitinib (Xeljanz™)

BACKGROUND

The etiopathogenesis of accompanying inflammatory phenomena and consequences of immunomodulation constitute a challenging and innovative field in the medical treatment of patients with autoimmune diseases.

AIM

Based on i) clinical management experience gained from this challenging clinical case and ii) selective references of reports published in the scientific medical literature, we present an unusual counterfactual scientific case report. A patient diagnosed with ulcerative colitis undergoing januskinase (JAK)-inhibitor therapy developed acuteappendicitis as an unusual complication or as a visceral side effect of immunosuppressive/anti-inflammatory therapy.

METHOD

Scientific case report.

RESULTS

(case description): Medical history: A 52-year-old male presented with spasmodic pain in the right lower abdomen lasting for two days (no fever, no bowel movement changes (no stool irregularities), no vomiting).

MEDICATION USED TO DATE

Steroid-resistant ulcerative colitis treated with immunosuppressive therapy (Adalimumab administered for 10 months [next generation anti-TNFα mAb], Vendolizumab for 9 months [α4β7 integrin antagonist], Tofacitinib for 6 months); fructose intolerance, no previous abdominal surgery; medication: XeljanzTM (Tofacitinib, 5 mg 2x1; JAK-inhibitor; PFIZER PHARMA GmbH, Berlin,Germany); MutaflorTM (1x1; Ardeypharm GmbH, Herdecke, Germany).

CLINICAL FINDINGS

Pressure pain in the right lower abdomen with local muscular defense (Mc-Burney's/Lanz's point positive), no peritonism, Psoas-muscle sign positive.

DIAGNOSTIC MEASURES

Laboratory parameters: standard value of white blood cell count, CrP: 25 mg/l.-Transabdominal ultrasound revealed hypertrophic 'appendix vermiformis' with detectable target-phenomenon and surrounding fluid.

DECISION-MAKING

Indication for laparoscopic exploration.

THERAPY

Under perioperative single-shot antibiotic administration with UnacidTM, the patient underwent emergency laparoscopic appendectomy due to confirmed acute appendicitis with additional lavage and placement of local drainage.

CLINICAL COURSE

The postoperative phase was uneventful (sufficient analgetic therapy, removal of local drainage on the 2nd postoperative day). The patient was discharged four days after surgery. Histopathology confirmed ulcero-phlegmonous, acute purulent appendicitis with fibrinous purulent mesenteriolitis.

FURTHER MEASURES

Immunosuppressive therapy was continued.

CONCLUSION

Based on the paradoxon of an acute inflammatory disease (acute appendicitis) seen in the case of a patient undergoing immunosuppressive/anti-inflammatory treatment using a JAK-Inhibitor for ulcerative colitis, we consider this case worthy of publication although this side effect has previously been described in patients with rheumatoid arthritis. This might be the manifestation of i) an immunomodulatory effect that reduced or at least altered mucosal defense, including an increased risk of opportunistic infections, presenting as a specific visceral 'side effect' of the JAK-Inhibitor and/or as a consequence; ii) an induced alternative inflammatory mechanism/proinflammatory signal transduction and - theoretically - an intestinal drainage defect in the segment of right colic artery with consecutive collection of necrotic cells and activation of inflammatory mediators.

Relationship between biomechanics and energy cost in graded treadmill running

The objective of this study was to determine whether the relationships between energy cost of running (Cr) and running mechanics during downhill (DR), level (LR) and uphill (UR) running could be related to fitness level. Nineteen athletes performed four experimental tests on an instrumented treadmill: one maximal incremental test in LR, and three randomized running bouts at constant speed (10 km h^-1) in LR, UR and DR (± 10% slope). Gas exchange, heart rate and ground reaction forces were collected during steady-state. Subjects were split into two groups using the median Cr for all participants. Contact time, duty factor, and positive external work correlated with Cr during UR (all, p < 0.05), while none of the mechanical variables correlated with Cr during LR and DR. Mechanical differences between the two groups were observed in UR only: contact time and step length were higher in the economical than in the non-economical group (both p < 0.031). This study shows that longer stance duration during UR contributes to lower energy expenditure and Cr (i.e., running economy improvement), which opens the way to optimize specific running training programs.

The instrumented single leg stance test detects early balance impairment in people with multiple sclerosis

Balance impairment is frequent in people with multiple sclerosis (pwMS) and affects risk of falls and quality of life. By using inertial measurement units (IMUs) on the Single Leg Stance Test (SLS) we aimed to discriminate healthy controls (HC) from pwMS and detect differences in balance endurance and quality. Thirdly, we wanted to test the correlation between instrumented SLS parameters and self-reported measures of gait and balance. Fifty-five pwMS with mild (EDSS<4) and moderate disability (EDSS≥4) and 20 HC performed the SLS with 3 IMUs placed on the feet and sacrum and filled the Twelve Item Multiple Sclerosis Walking Scale (MSWS-12) questionnaire. A linear mixed model was used to compare differences in the automated balance measures. Balance duration was significantly longer in HC compared to pwMS (p < 0.001) and between the two disability groups (p < 0.001). Instrumented measures identified that trunk stability (normalized mediolateral and antero-posterior center of mass stability) had the strongest association with disability (R2 marginal 0.30, p < 0.001) and correlated well with MSWS-12 (R = 0.650, p < 0.001). PwMS tended to overestimate own balance compared to measured balance duration. The use of both self-reported and objective assessments from IMUs can secure the follow-up of balance in pwMS.

[Traumatic injuries of the kidney and the urinary tract in blunt abdominal trauma]

BACKGROUND

In the context of blunt abdominal trauma, injuries to the urinary tracts often occur, especially in polytrauma patients. Urotrauma is rarely immediately life-threatening but can lead to serious complications and chronic functional limitations during treatment. Therefore early urological involvement is crucial for adequate interdisciplinary treatment.

METHODS

The most important facts for the clinical routine on the consultant urological management of urogenital injuries in blunt abdominal trauma are discussed according to the European "EAU guidelines on Urological Trauma" and the German "S3 guidelines on Polytrauma/Treatment of Severely Injured Patients" as well as the relevant literature.

RESULTS

Urinary tract injuries can occur even with an initially inconspicuous status and always require explicit exclusion diagnostics by means of contrast medium tomography of the entire urinary tract and, if necessary, by means of urographic and endoscopic examinations. The most common urological intervention is catheterization of the urinary tract which is often required. Less common is urological surgery, which should be coordinated interdisciplinarily with visceral and trauma surgery. More than 90% of vitally threatening kidney injuries (usually up to the American Association for the Surgery of Trauma (AAST) grades 4-5) are now treated by interventional radiology.

CONCLUSION

Due to possible complex injury patterns in blunt abdominal trauma, these patients should ideally be directed to (certified) trauma centers with subspecialized or maximum care from the departments of visceral and vascular surgery, trauma surgery, interventional radiology and urology.

[Consultations by senior physicians in general and abdominal surgery for other medical disciplines over 10 years at a tertiary center-Is a fast time-consuming processing necessary? : Spectrum of clinical findings, diagnoses and treatment decision making]

BACKGROUND

The challenges of an adequate, efficient and rational medical treatment and care of patients are always associated with an interprofessional activity of several specialist disciplines.

AIM

The spectrum of variable diagnoses and the profile of surgical decision-making with further surgical measures within the framework of senior physician consultation in general and visceral surgery for neighboring medical disciplines were analyzed on a representative patient cohort over a defined observational time period.

PATIENTS AND METHODS

All consecutive patients (n = 549 cases) were documented as part of a clinical systematic prospective single center observational study at a tertiary center using a computer-based patient registry over 10 years (1 October 2006-30 September 2016). The data were analyzed with respect to the spectrum of clinical findings, diagnoses, treatment decisions and the influencing factors as well as gender and age differences and time-dependent developmental trends using χ2-tests and U‑tests.

RESULTS (KEY POINTS)

The predominant discipline for requests for surgical consultation was cardiology (19.9%) followed by surgical disciplines (11.8%) and gastroenterology (11.3%). Disorders of wound healing (7.1%) and acute abdomen (7.1%) were predominant in the diagnostic profile. In 11.7% of the patients the indications for immediate surgery were derived, whereas in 12.9% elective surgery was recommended. The conformity rate of suspected and definitive diagnoses was only 58.4%.

CONCLUSION

The surgical consultation work is an important mainstay of a sufficient and especially timely clarification of surgically relevant questions in nearly all medical institutions and especially in a center. This serves i) the quality assurance of surgery in the clinical care of patients with need of additional interdisciplinary needs for surgical treatment in the daily practice of general and abdominal surgery in research on clinical care, ii) clinical marketing and monetary aspects in the sense of patient recruitment and iii) last but not least to provide emergency care of patients. Due to the high proportion of 12% of subsequent emergency operations, which were derived from requests for general and visceral surgical consultations, such requests must be processed promptly during working hours.

Estimation of horizontal running power using foot-worn inertial measurement units

Feedback of power during running is a promising tool for training and determining pacing strategies. However, current power estimation methods show low validity and are not customized for running on different slopes. To address this issue, we developed three machine-learning models to estimate peak horizontal power for level, uphill, and downhill running using gait spatiotemporal parameters, accelerometer, and gyroscope signals extracted from foot-worn IMUs. The prediction was compared to reference horizontal power obtained during running on a treadmill with an embedded force plate. For each model, we trained an elastic net and a neural network and validated it with a dataset of 34 active adults across a range of speeds and slopes. For the uphill and level running, the concentric phase of the gait cycle was considered, and the neural network model led to the lowest error (median ± interquartile range) of 1.7% ± 12.5% and 3.2% ± 13.4%, respectively. The eccentric phase was considered relevant for downhill running, wherein the elastic net model provided the lowest error of 1.8% ± 14.1%. Results showed a similar performance across a range of different speed/slope running conditions. The findings highlighted the potential of using interpretable biomechanical features in machine learning models for the estimating horizontal power. The simplicity of the models makes them suitable for implementation on embedded systems with limited processing and energy storage capacity. The proposed method meets the requirements for applications needing accurate near real-time feedback and complements existing gait analysis algorithms based on foot-worn IMUs.

Inertial Sensor-Based Estimation of Temporal Events in Skating Sub-Techniques While In-Field Roller Skiing

The aim of this study was to test and adapt a treadmill-developed method for determination of inner-cycle parameters and sub-technique in cross-country roller ski skating for a field application. The method is based on detecting initial and final ground contact of poles and skis during cyclic movements. Eleven athletes skied 4 laps of 2.5 km at low- and high-endurance intensities, using 2 types of skis with different rolling coefficients. Participants were equipped with inertial measurement units attached to their wrists and skis, and insoles with pressure sensors and poles with force measurements were used as reference systems. The method based on inertial measurement units was able to detect >97% of the temporal events detected with the reference system. The inner-cycle temporal parameters had a precision ranging from 49 to 59 milliseconds, corresponding to 3.9% to 13.7% of the corresponding inner-cycle duration. Overall, this study showed good reliability of using inertial measurement units on athletes' wrists and skis to determine temporal events, inner-cycle parameters, and the performed sub-techniques in cross-country roller ski skating in field conditions.

Cytokines and intestinal epithelial permeability: A systematic review

BACKGROUND

The intestinal mucosa is composed of a well-organized epithelium, acting as a physical barrier to harmful luminal contents, while simultaneously ensuring absorption of physiological nutrients and solutes. Increased intestinal permeability has been described in various chronic diseases, leading to abnormal activation of subepithelial immune cells and overproduction of inflammatory mediators. This review aimed to summarize and evaluate the effects of cytokines on intestinal permeability.

METHODS

A systematic review of the literature was performed in the Medline, Cochrane and Embase databases, up to 01/04/2022, to identify published studies assessing the direct effect of cytokines on intestinal permeability. We collected data on the study design, the method of assessment of intestinal permeability, the type of intervention and the subsequent effect on gut permeability.

RESULTS

A total of 120 publications were included, describing a total of 89 in vitro and 44 in vivo studies. TNFα, IFNγ or IL-1β were the most frequently studied cytokines, inducing an increase in intestinal permeability through a myosin light-chain-mediated mechanism. In situations associated with intestinal barrier disruption, such as inflammatory bowel diseases, in vivo studies showed that anti-TNFα treatment decreased intestinal permeability while achieving clinical recovery. In contrast to TNFα, IL-10 decreased permeability in conditions associated with intestinal hyperpermeability. For some cytokines (e.g. IL-17, IL-23), results are conflicting, with both an increase and a decrease in gut permeability reported, depending on the study model, methodology, or the studied conditions (e.g. burn injury, colitis, ischemia, sepsis).

CONCLUSION

This systematic review provides evidence that intestinal permeability can be directly influenced by cytokines in numerous conditions. The immune environment probably plays an important role, given the variability of their effect, according to different conditions. A better understanding of these mechanisms could open new therapeutic perspectives for disorders associated with gut barrier dysfunction.

Vertical and Leg stiffness modeling during running: effect of speed and incline

A spring mass model is often used to describe human running, allowing to understand the concept of elastic energy storage and restitution. The stiffness of the spring is a key parameter and different methods have been developed to estimate both the vertical and the leg stiffness components. Nevertheless, the validity and the range of application of these models are still debated. The aim of the present study was to compare three methods (i.e., Temporal, Kinetic and Kinematic-Kinetic) of stiffness determination. Twenty-nine healthy participants equipped with reflective markers performed 5-min running bouts at four running speeds and eight inclines on an instrumented treadmill surrounded by a tri-dimensional motion camera system. The three methods provided valid results among the different speeds, but the reference method (i.e., Kinematic-Kinetic) provided higher vertical stiffness and lower leg stiffness than the two other methods (both p<0.001). On inclined terrain, the method using temporal parameters provided non valid outcomes and should not be used. Finally, this study highlights that both the assumption of symmetry between compression and decompression phases or the estimation of the vertical displacement and changes in leg length are the major sources of errors when comparing different speeds or different slopes.

Introduction of laparoscopic nephrectomy for autosomal dominant polycystic kidney disease as the standard procedure

PURPOSE

Autosomal dominant polycystic kidney disease (ADPKD) is a common hereditary disorder and accounts for 5-10% of all cases of kidney failure. 50% of ADPKD patients reach kidney failure by the age of 58 years requiring dialysis or transplantation. Nephrectomy is performed in up to 20% of patients due to compressive symptoms, renal-related complications or in preparation for kidney transplantation. However, due to the large kidney size in ADPKD, nephrectomy can come with a considerable burden. Here we evaluate our institution's experience of laparoscopic nephrectomy (LN) as an alternative to open nephrectomy (ON) for ADPKD patients.

MATERIALS AND METHODS

We report the results of the first 12 consecutive LN for ADPKD from August 2020 to August 2021 in our institution. These results were compared with the 12 most recent performed ON for ADPKD at the same institution (09/2017 to 07/2020). Intra- and postoperative parameters were collected and analyzed. Health related quality of life (HRQoL) was assessed using the SF36 questionnaire.

RESULTS

Age, sex, and median preoperative kidney volumes were not significantly different between the two analyzed groups. Intraoperative estimated blood loss was significantly less in the laparoscopic group (33 ml (0-200 ml)) in comparison to the open group (186 ml (0-800 ml)) and postoperative need for blood transfusion was significantly reduced in the laparoscopic group (p = 0.0462). Operative time was significantly longer if LN was performed (158 min (85-227 min)) compared to the open procedure (107 min (56-174 min)) (p = 0.0079). In both groups one postoperative complication Clavien Dindo ≥ 3 occurred with the need of revision surgery. SF36 HRQol questionnaire revealed excellent postoperative quality of life after LN.

CONCLUSION

LN in ADPKD patients is a safe and effective operative procedure independent of kidney size with excellent postoperative outcomes and benefits of minimally invasive surgery. Compared with the open procedure patients profit from significantly less need for transfusion with comparable postoperative complication rates. However significant longer operation times need to be taken in account.

Correspondence Between Values of Vertical Loading Rate and Oxygen Consumption During Inclined Running

Purpose

The aim of this study was to provide a theoretical model to predict the vertical loading rate (VLR) at different slopes and speeds during incline running.

Methods

Twenty-nine healthy subjects running at least once a week performed in a randomized order 4-min running trials on an instrumented treadmill at various speeds (8, 10, 12, and 14 km h−1) and slopes (− 20%, − 10%, − 5%, 0%, + 5%, + 10%, + 15%, + 20%). Heart rate, gas exchanges and ground reaction forces were recorded. The VLR was then calculated as the slope of the vertical force between 20 and 80% of the duration from initial foot contact to the impact peak.

Results

There was no difference in VLR between the four different uphill conditions at given running speeds, but it was reduced by 27% at 5% slope and by 54% at 10% slope for the same metabolic demand (similar $${\dot{\text{V}}\text{O}}_{{2}}$$ V ˙ O 2 ), when compared to level running. The average VLR measured at maximal aerobic intensity during level running would be decreased by 52.7% at + 5%, by 63.0% at + 10%, and by 73.3% at + 15% slope. Moreover, VLR was dependent on the slope in downhill conditions.

Conclusion

This study highlights the possibility to use uphill running to minimize rate of mechanical load (i.e., osteoarticular load) from foot impact on the ground and as a time-efficient exercise routine (i.e., same energy expenditure than in level running in less time).

Inner-Cycle Phases Can Be Estimated from a Single Inertial Sensor by Long Short-Term Memory Neural Network in Roller-Ski Skating

OBJECTIVE

The aim of this study was to provide a new machine learning method to determine temporal events and inner-cycle parameters (e.g., cycle, pole and ski contact and swing time) in cross-country roller-ski skating on the field, using a single inertial measurement unit (IMU).

METHODS

The developed method is based on long short-term memory neural networks to detect the initial and final contact of the poles and skis with the ground during the cyclic movements. Eleven athletes skied four laps of 2.5 km at a low and high intensity using skis with two different rolling coefficients. They were equipped with IMUs attached to the upper back, lower back and to the sternum. Data from force insoles and force poles were used as the reference system.

RESULTS

The IMU placed on the upper back provided the best results, as the LSTM network was able to determine the temporal events with a mean error ranging from -1 to 11 ms and had a standard deviation (SD) of the error between 64 and 70 ms. The corresponding inner-cycle parameters were calculated with a mean error ranging from -11 to 12 ms and an SD between 66 and 74 ms. The method detected 95% of the events for the poles and 87% of the events for the skis.

CONCLUSION

The proposed LSTM method provides a promising tool for assessing temporal events and inner-cycle phases in roller-ski skating, showing the potential of using a single IMU to estimate different spatiotemporal parameters of human locomotion.

Patients with carotid intraplaque hemorrhage have higher incidence of cerebral microbleeds

Background

Carotid intraplaque hemorrhage (IPH) is considered a strong marker of histologically defined plaque vulnerability leading to cerebrovascular ischemic events. Cerebral microbleeds (CMBs) represent hemorrhage-prone small vessel disease and they are a common finding on brain MRI in patients with cerebrovascular disease. However, the potential mechanism and the risk for CMBs are not clear. The characteristics of carotid lesions have been considered relevant in the relationship between carotid artery atherosclerosis and the presence of CMBs. The potential association between carotid IPH histologically defined and CMBs has not been investigated yet.

Purpose

We have previously reported the prevalence of IPH in patients with non-obstructive carotid disease in patients who underwent carotid endarterectomy (CEA). In this study, we aimed to investigate whether the presence and the extent of carotid IPH are related to the existence of CMBs. We hypothesized that patients with carotid IPH would have a higher risk of CMBs.

Methods

This retrospective study enrolled 101 consecutive patients undergoing CEA with symptomatic (including ischemic stroke, TIA, and amaurosis fugax) or asymptomatic ipsilateral carotid artery disease. Carotid plaque specimens were collected at CEA from all the patients and stained with Movat Pentachrome to identify the presence and the extent (%) of IPH. Neck CTA was obtained to measure the degree of carotid stenosis. Brain MRI was pre-surgically performed and CMBs were studied using T2*-weighted gradient-recalled echo (GRE) or susceptibility-weighted imaging (SWI) sequence. The CMBs were counted and localized. Clinical and biochemical data, comorbidities, and medications were recorded. The association between carotid IPH and CMBs was examined adjusted for other risk factors.

Results

The presence of carotid IPH was in 57 (56.4%) patients. CMBs were more observed in patients with carotid IPH compared to those without IPH [19 (33.3%) vs 5 (11.4%); p=0.010]. Logistic regression analysis demonstrated an association between the extent of IPH in the carotid atheroma and the presence of CMBs [OR 1.051 (95% CI 1.012–1.090); p=0.009]. Moreover, the carotid IPH extent was associated with the number of CMBs (p=0.004). In patients with CMBs, the median degree of ipsilateral carotid stenosis was 40% (35–65%) and it was 70% (50–80%) in those without CMBs, with a significant difference between the two groups (p=0.049).

Conclusions

In patients undergoing CEA, the histologically defined presence of carotid IPH and its extent are associated with CMBs on brain MR imaging. CMBs may be a potential mechanism for cerebrovascular events in patients with carotid atherosclerotic IPH and they may be an imaging marker that can distinguish the severity of the carotid artery disease.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Mayo Clinic Foundation

Repeated practice runs during on-snow training do not generate any measurable neuromuscular alterations in elite alpine skiers

Background

Alpine skiers typically train using repeated practice runs requiring high bursts of muscle activity but there is little field-based evidence characterizing neuromuscular function across successive runs.

Purpose

To examine the impact of repeated ski runs on electromyographic activity (EMG) of the knee extensors and flexors in elite alpine skiers.

Methods

Nineteen national team alpine skiers were tested during regular ski training [Slalom (SL), Giant Slalom (GS), Super Giant Slalom and Downhill (Speed)] for a total of 39 training sessions. The surface EMG of the vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM), biceps femoris (BF) and semimembranosus/semitendinosus (SMST) muscles was continuously recorded along with right knee and hip angles. The EMG root mean square signal was normalized to a maximal voluntary contraction (%MVC). The first and fourth runs of the training session were compared.

Results

There was no meaningful main effect of run on EMG relative activation time or mean power frequency beyond the skier's intrinsic variability. However, EMG activity of the vastii increased from the first to the fourth run in SL [VM, ~+3%MVC for IL and outside leg (OL), p = 0.035)], speed (VL, IL:+6%/OL:+11%, p = 0.015), and GS (VM, IL:0/OL:+7%, p < 0.001); the later with an interaction with leg (p < 0.001) due to a localized increase on the OL. The run time and turn time did not change from the first to the fourth run. There were no meaningful changes in angular velocities, amplitude of movement, or maximal and minimal angles.

Conclusion

Neuromuscular activity remains highly stable in elite skiers with low variability across four runs.

Sensor-based gait analyses of the six-minute walk test identify qualitative improvement in gait parameters of people with multiple sclerosis after rehabilitation

The aim of this work was to determine whether wearable inertial measurement units (IMUs) could detect gait improvements across different disability groups of people with Multiple Sclerosis (pwMS) by the six-minute walk test (6MWT) during a rehabilitation stay in a specialized rehabilitation center. Forty-six pwMS and 20 healthy controls (HC) were included in the study. They performed the 6MWT with two inertial measurement units (IMUs) placed on the feet. Thirty-two of the pwMS were retested at the end of the stay. PwMS were divided in a mild-disability and a moderate-disability group. The 6MWT was divided in six sections of 1 min each for technical analysis, and linear mixed models were used for statistical analyses. The comparison between the two disability groups and HC highlighted significant differences for each gait parameter (all p < 0.001). The crossing effect between the test–retest and the two disability groups showed greater improvement for the moderate-disability group. Finally, the gait parameter with the higher effect size, allowing the best differentiation between the disability groups, was the foot flat ratio (R² = 0.53). Gait analyses from wearable sensors identified different evolutions of gait patterns during the 6MWT in pwMS with different physical disability. The measured effect of a short-time rehabilitation on gait with 6MWT was higher for pwMS with higher degree of disability. Using IMUs in a clinical setting allowed to identify significant changes in inter-stride gait patterns. Wearable sensors and key parameters have the potential as useful clinical tools for focusing on gait in pwMS.

Solitary colorectal liver metastasis: overview of treatment strategies and role of prognostic factors

The following is an overview of the treatment strategies and the prognostic factors to consider in the therapeutic choice of patients characterized by solitary colorectal liver metastasis. Liver resection is the only potential curative option; nevertheless, only 25% of the patients are considered to be eligible for surgery. To expand the potentially resectable pool of patients, surgeons developed multidisciplinary techniques like portal vein embolization, two-stage hepatectomy or associating liver partition and portal vein ligation for staged hepatectomy. Moreover, mini-invasive surgery is gaining support, since it offers lower post-operative complication rates and shorter hospital stay with no differences in long-term outcomes. In case of unresectable disease, various techniques of local ablation have been developed. Radiofrequency ablation is the most commonly used form of thermal ablation: it is widely used for unresectable patients and is trying to find its role in patients with small resectable metastasis. The identification of prognostic factors is crucial in the choice of the treatment strategy. Previous works that focused on patients with solitary colorectal liver metastasis obtained trustable negative predictive factors such as presence of lymph-node metastasis in the primary tumour, synchronous metastasis, R status, right-sided primary colon tumor, and additional presence of extrahepatic tumour lesion. Even the time factor could turn into a predictor of tumour biology as well as further clinical course, and could be helpful to discern patients with worse prognosis.

2021 opinion from the CUROPF on THE efficacy and safety of mid-urethral slings used in women WITH urinary stress incontinence

OBJECTIVE

To determine the usefulness of mid-urethral slings (MUS) in the surgical management of women presenting with urinary stress incontinence (USI) METHOD: A consensus committee of multidisciplinary experts (CUROPF) was convened and focused on PICO questions concerning the efficacy and safety of MUS surgery compared to other procedures and concerning which approach (retropubic (RP) vs transobturator (TO)) should be proposed as a first-line MUS surgery for specific subpopulations (obese; intrinsic sphincteric deficiency (ISD); elderly) RESULTS: As compared to other procedures (urethral bulking agents, traditional slings and open colposuspension), the MUS procedure should be proposed as the first-line surgical therapy (strong agreement). MUS surgery can be associated with complications and proper pre-operative informed consent is mandatory (strong agreement). Mini-slings (SIS/SIMS) should only be proposed in clinical trials (strong agreement). Both RP and TO approaches may be proposed for the insertion of MUS (strong agreement). However, if the woman is willing to accept a moderate increase in per-operative risk, the RP approach should be preferred (strong agreement) since it is associated with higher very long-term cure rates and as it is possible to completely remove the sling surgically if a severe complication occurs. The RP approach should be used for the insertion of MUS in a woman presenting with ISD (strong agreement). Either the RP or TO approach should be used for the insertion of MUS in an obese woman presenting with USI (strong agreement). In very obese women (BMI ≥35-40kg/m²), weight loss should be preferred prior to MUS surgery and bariatric surgery should be discussed (strong agreement) CONCLUSION: The current Opinion provides an appropriate strategy for both the selection of patients and the best therapeutic approach in women presenting with USI.

[Complications of mid-urethral sling - A review from the Committee for Female Urology and Pelviperineology for the French Association of Urology]

INTRODUCTION

Placement of a mid-urethral sling is the gold standard in the surgical management of stress urinary incontinence in women in France. The cure rate of this material is no longer to be demonstrated, but the per- and post-operative complications are currently the subject of a growing controversy not only in Europe but also across the Channel and across the Atlantic, having led to the modification of operative indications. In France, recommendations are also evolving with a stricter framework for indications for surgery by multidisciplinary consultation meeting and an obligation for postoperative follow-up in the short and long term.

OBJECTIVES

In this context, CUROPF realized a review of the literature bringing together the available scientific evidence concerning the occurrence of per- and post-operative complications relating to the installation of mid urethral sling. The bibliographic search was carried out using the Medline database and 123 articles were selected.

RESULTS

Analysis of the data highlights various complications, depending on the implanted material, the patient and the indication for surgery. The retro-pubic mid urethral sling provides more bladder erosion during surgery (up to 14%), more suprapubic pain (up to 4%) and more acute urinary retention (up to 19,7%) and postoperative dysuria (up to 26%). The trans obturator mid-urethral sling is responsible for more vaginal erosion during the operation (up to 10,9%), more lower limb pain of neurological origin (up to 26,7%). The risk of developing over active bladder is similar in both procedures (up to 33%). But these risks of complications must be balanced by the strong impact of urinary incontinence surgery on the overall quality of life of these women.

CONCLUSION

Thus, surgical failure and long term complications exist but should not limit the surgical management of stress urinary incontinence with mid urethral tape. Women should be treated with individualized decision-making process and long-term follow -up is necessary.

Physiological and Biomechanical Responses to Cross-Country Skiing in Varying Terrain: Low- vs. High-Intensity

The purposes of our study were to investigate the physiological and biomechanical responses to low-intensity (LI) and high-intensity (HI) roller ski skating on varying terrain and compare these responses between training intensities. Nine elite male skiers performed treadmill roller skiing consisting of two 21 min sessions (7 × 3 min laps) at LI and HI with the same set inclines and intensity-dependent speeds (LI/HI: distance: 5.8/7.5 km, average speed: 16.7/21.3 km/h). Physiological and biomechanical variables were measured continuously, and each movement cycle and sub-technique employed were detected and classified with a machine learning model. Both the LI and HI sessions induced large terrain-dependent fluctuations (relative to the maximal levels) in heart rate (HR, 17.7 vs. 12.2%-points), oxygen uptake (V.O2, 33.0 vs. 31.7%-points), and muscle oxygen saturation in the triceps brachii (23.9 vs. 33.4%-points) and vastus lateralis (12.6 vs. 24.3%-points). A sub-technique dependency in relative power contribution from poles and skis exhibited a time-dependent shift from Lap 1 to Lap 7 toward gradually more ski power (6.6 vs. 7.8%-points, both p < 0.01). The terrain-dependent fluctuations did not differ between LI and HI for V.O2 (p = 0.50), whereas HR fluctuated less (p < 0.01) and displayed a time-dependent increase from Lap 2 to Lap 7 (7.8%-points, p > 0.01) during HI. Oxygen saturation shifted 2.4% points more for legs than arms from LI to HI (p > 0.05) and regarding sub-technique, 14.7% points more G3 on behalf of G2 was employed on the steepest uphill during HI (p < 0.05). Within all sub-techniques, cycle length increased two to three times more than cycle rate from LI to HI in the same terrains, while the corresponding poling time decreased more than ski contact time (all p > 0.05). In sum, both LI and HI cross-country (XC) skiing on varying terrain induce large terrain-dependent physiological and biomechanical fluctuations, similar to the patterns found during XC skiing competitions. The primary differences between training intensities were the time-dependent increase in HR, reduced relative oxygen saturation in the legs compared to the arms, and greater use of G3 on steep uphill terrain during HI training, whereas sub-technique selection, cycle rate, and pole vs. ski power distribution were similar across intensities on flat and moderately uphill terrain.

Estimation of Mechanical Power Output Employing Deep Learning on Inertial Measurement Data in Roller Ski Skating

The ability to optimize power generation in sports is imperative, both for understanding and balancing training load correctly, and for optimizing competition performance. In this paper, we aim to estimate mechanical power output by employing a time-sequential information-based deep Long Short-Term Memory (LSTM) neural network from multiple inertial measurement units (IMUs). Thirteen athletes conducted roller ski skating trials on a treadmill with varying incline and speed. The acceleration and gyroscope data collected with the IMUs were run through statistical feature processing, before being used by the deep learning model to estimate power output. The model was thereafter used for prediction of power from test data using two approaches. First, a user-dependent case was explored, reaching a power estimation within 3.5% error. Second, a user-independent case was developed, reaching an error of 11.6% for the power estimation. Finally, the LSTM model was compared to two other machine learning models and was found to be superior. In conclusion, the user-dependent model allows for precise estimation of roller skiing power output after training the model on data from each athlete. The user-independent model provides less accurate estimation; however, the accuracy may be sufficient for providing valuable information for recreational skiers.

Safety of biologic treatments in solid organ transplant recipients: A systematic review

BACKGROUND

The development of biological treatments has transformed the management of a broad spectrum of autoimmune/inflammatory diseases. However, little is known about their use in solid-organ transplant recipients. This study aimed to evaluate complications occurring with biologic treatments in solid-organ transplant recipients.

METHODS

A systematic review of the literature was performed in the Medline, Embase and Cochrane databases, up to 01/10/2020, to identify published case reports or series reporting the use of biologic treatments in solid organ transplant recipients with chronic inflammatory diseases. We collected data on patient characteristics and reported complications.

RESULTS

In total, 57 articles were included, totalling 187 patients (141 liver, 42 kidney, 3 heart, and 1 liver-kidney transplant recipients). Inflammatory bowel diseases represented the most common indication for biologic treatment initiation (80.7%), followed by rheumatic diseases (7.5%), hereditary periodic fever syndromes (5.9%) and psoriasis (4.8%). Anti-TNFα were mainly used (77.5%; mainly monoclonal antibodies (70%) compared to soluble receptor etanercept (7.5%)), followed by the anti-α4β7 integrin, vedolizumab (27.3%) and the anti-IL-1R, anakinra (6.9%). Median treatment duration was 12 months. Infections occurred in 54 patients (28.9%) through 88 recorded events. No therapeutic or demographic factors were associated with occurrence of infection. Sixteen patients (8.6%) developed malignancies, and acute graft rejections occurred in 5 patients (2.7%). Among the 187 patients, 9 deaths were reported (4.8%).

CONCLUSIONS

This review assembles the largest number of published reports regarding the use of biological treatments in solid organ transplant recipients, providing data about their safety. Further comparative studies are needed to assess the safety of biological treatments in transplanted patients.

Indirect Estimation of Breathing Rate from Heart Rate Monitoring System during Running

Recent advances in wearable technologies integrating multi-modal sensors have enabled the in-field monitoring of several physiological metrics. In sport applications, wearable devices have been widely used to improve performance while minimizing the risk of injuries and illness. The objective of this project is to estimate breathing rate (BR) from respiratory sinus arrhythmia (RSA) using heart rate (HR) recorded with a chest belt during physical activities, yielding additional physiological insight without the need of an additional sensor. Thirty-one healthy adults performed a run at increasing speed until exhaustion on an instrumented treadmill. RR intervals were measured using the Polar H10 HR monitoring system attached to a chest belt. A metabolic measurement system was used as a reference to evaluate the accuracy of the BR estimation. The evaluation of the algorithms consisted of exploring two pre-processing methods (band-pass filters and relative RR intervals transformation) with different instantaneous frequency tracking algorithms (short-term Fourier transform, single frequency tracking, harmonic frequency tracking and peak detection). The two most accurate BR estimations were achieved by combining band-pass filters with short-term Fourier transform, and relative RR intervals transformation with harmonic frequency tracking, showing 5.5% and 7.6% errors, respectively. These two methods were found to provide reasonably accurate BR estimation over a wide range of breathing frequency. Future challenges consist in applying/validating our approaches during in-field endurance running in the context of fatigue assessment.

Temporal and kinematic patterns distinguishing the G2 from the G4 skating sub-technique

In cross-country ski skating, both the G2 and G4 sub-techniques involve one pole push for every second ski push but are used at largely different speed-slope ranges. The aim of this study was to compare temporal and kinematic patterns between G2 and G4 at both identical and different speed-slope conditions. A mixed model was used to analyse spatio-temporal parameters, while a combination of dynamic time warping and statistical parametric mapping was used to compare time traces. Main spatio-temporal parameters, such as cycle time, ski contact time and swing time, differed between G2 and G4 (all p < 0.01). Moreover, two forward and more pronounced acceleration phases of the centre of mass (CoM) were visible in G4 while only one acceleration phase was present in G2. The more continuous propulsion in G2 allows for maintaining a more constant speed at steep slopes and low speeds where this sub-technique is preferred. In contrast, the achievement of high speeds while skiing on flatter terrain seem to require more dynamic motion with shorter, more explosive propulsion periods allowed for in G4. In conclusion, G2 and G4 are two unique movements as characterised by fundamentally different CoM motion and should be denoted as two different sub-techniques.

Level, Uphill, and Downhill Running Economy Values Are Correlated Except on Steep Slopes

The aim of this study was first to determine if level, uphill, and downhill energy cost of running (ECR) values were correlated at different slopes and for different running speeds, and second, to determine the influence of lower limb strength on ECR. Twenty-nine healthy subjects completed a randomized series of 4-min running bouts on an instrumented treadmill to determine their cardiorespiratory and mechanical (i.e., ground reaction forces) responses at different constant speeds (8, 10, 12, and 14 km·h⁻¹) and different slopes (−20, −10, −5, 0, +5, +10, +15, and +20%). The subjects also performed a knee extensor (KE) strength assessment. Oxygen and energy costs of running values were correlated between all slopes by pooling all running speeds (all r² ≥ 0.27; p ≤ 0.021), except between the steepest uphill vs. level and the steepest downhill slope (i.e., +20% vs. 0% and −20% slopes; both p ≥ 0.214). When pooled across all running speeds, the ECR was inversely correlated with KE isometric maximal torque for the level and downhill running conditions (all r² ≥ 0.24; p ≤ 0.049) except for the steepest downhill slope (−20%), but not for any uphill slopes. The optimal downhill grade (i.e., lowest oxygen cost) varied between running speeds and ranged from −14% and −20% (all p < 0.001). The present results suggest that compared to level and shallow slopes, on steep slopes ~±20%, running energetics are determined by different factors (i.e., reduced bouncing mechanism, greater muscle strength for negative slopes, and cardiopulmonary fitness for positive slopes). On shallow negative slopes and during level running, ECR is related to KE strength.

Home vision monitoring in patients with maculopathy: Real-life study of the OdySight application

INTRODUCTION

The goal of the present study was to analyze the implementation and clinical efficacy of OdySight, a mobile medical application for the remote monitoring of patients with maculopathy.

MATERIALS AND METHODS

In all, 60 patients with edematous maculopathies receiving traditional clinical treatment (PRN or Treat & Extend) were provided with OdySight to detect changes in visual acuity from home. To determine both the feasibility and reliability of the application, its use by patients (both testing and game play), as well as the processing of alerts by the clinical team, were analyzed during the first year.

RESULTS

The female-to-male ratio was 3:2, with a mean age of 64 years. 52% of patients presented with age-related macular degeneration, 31% with high myopia, 11% with retinal vein occlusion, and 6% with diabetic maculopathy. The conversion rate (defined as the percentage of patients completing at least one test following prescription) and the nine-month retention rate (percentage of active patients) were 61% and 24% respectively. Patients aged 50 to 70 years and those whose use of the app included game play represent 75% of active patients at 9 months. The 22 active patients performed 483 visual acuity tests, completed 1,667 game sessions, and underwent 77 in-person consultations. During the trial period, the clinical team processed 19 alerts, on average in fewer than 6 days. Decreases in visual acuity were detected with a sensitivity of 92% and specificity of 99%.

DISCUSSION

The use of connected and mobile devices today is widespread, as is interest in mobile medical applications. Long-term treatments for maculopathies can be a difficult burden to bear, both for patients and healthcare practitioners. Overcoming the challenges associated with the successful remote detection of recurrences thus represents a significant opportunity for improving patient care. The implementation of novel digital tools requires the cooperation of the clinical team as a whole, to both inform and motivate patients. OdySight demonstrates satisfactory detection rates, thanks to reliable and reproducible home testing, and can thus serve as a supplementary tool for patients whose consultations are often spaced several months apart. Implementation can be nonetheless improved by facilitating alert processing, a goal which necessitates active adaptation of clinical practices. In general, active patients were very satisfied with this personalized service.

CONCLUSION

Improved medical support, plus the amusing nature of the tests and games, both bolster long-term use of the OdySight app. The application allows for the remote monitoring of changes in visual acuity and affords patients and practitioners an added level of protection, particularly during long intervals between treatments and at the end of a treatment course. To ensure proper implementation, clinics should focus on reinforcing and modernizing the clinical pathway, from patient intake to the injection room.

Towards more valid simulations of slopestyle and big air jumps: Aerodynamics during in-run and flight phase

OBJECTIVES

This study aimed to investigate air drag and lift during the in-run and flight phase of ski and snowboard slopestyle and big air, to allow more valid modeling of jumps and hence reduce injury risk.

DESIGN

We present an experimental, multiple single athlete study based on wind tunnel measurements of 4 skiers and 3 snowboarders.

METHODS

Measurements were carried out in a closed loop wind tunnel, measuring airflow speed and 3D forces acting on the athletes. Athletes performed trials in typical postures at 35, 60 and 85 km/h wearing slim-, regular- and wide fit apparel. Drag and lift area (c_DA; c_LA) were calculated and analyzed using linear and multiple regression to describe their dependencies on posture, apparel and speed.

RESULTS

c_DA values were higher than earlier assumed and ranged from 0.3 to 0.95 m² for skiers and from 0.35 to 0.55 m² for snowboarders, primarily dominated by posture, and followed by apparel. c_LA ranged from -0.1 to 0.45 m² for skiers and from 0.04 to 0.17 m² for snowboarders. To facilitate more valid jump modeling posture- and apparel-dependent formulations for air drag coefficients were provided and the consequences of sport specific differences on modeling were highlighted.

CONCLUSIONS

Applying the air drag coefficients and relationships determined in this study will help to improve validity of jump modeling in big air and slopestyle. The variability in aerodynamic forces in slopestyle and big air is caused by differences between sports, posture and apparel.

Continuous Analysis of Marathon Running Using Inertial Sensors: Hitting Two Walls?

Marathon running involves complex mechanisms that cannot be measured with objective metrics or laboratory equipment. The emergence of wearable sensors introduced new opportunities, allowing the continuous recording of relevant parameters. The present study aimed to assess the evolution of stride-by-stride spatio-temporal parameters, stiffness, and foot strike angle during a marathon and determine possible abrupt changes in running patterns. Twelve recreational runners were equipped with a Global Navigation Satellite System watch, and two inertial measurement units clamped on each foot during a marathon race. Data were split into eight 5-km sections and only level parts were analyzed. We observed gradual increases in contact time and duty factor as well as decreases in flight time, swing time, stride length, speed, maximal vertical force and stiffness during the race. Surprisingly, the average foot strike angle decreased during the race, but each participant maintained a rearfoot strike until the end. Two abrupt changes were also detected around km 25 and km 35. These two breaks are possibly due to the alteration of the stretch-shortening cycle combined with physiological limits. This study highlights new measurable phenomena that can only be analyzed through continuous monitoring of runners over a long period of time.

Which experimental models and explorations to use in regenerative endodontics? A comprehensive review on standard practices

Since the discovery of dental pulp stem cells, a lot of teams have expressed an interest in dental pulp regeneration. Many approaches, experimental models and biological explorations have been developed, each including the use of stem cells and scaffolds with the final goal being clinical application in humans. In this review, the authors' objective was to compare the experimental models and strategies used for the development of biomaterials for tissue engineering of dental pulp with stem cells. Electronic queries were conducted on PubMed using the following terms: pulp regeneration, scaffold, stem cells, tissue engineering and biomaterial. The extracted data included the following information: the strategy envisaged, the type of stem cells, the experimental models, the exploration or analysis methods, the cytotoxicity or viability or proliferation cellular tests, the tests of scaffold antibacterial properties and take into account the vascularization of the regenerated dental pulp. From the 71 selected articles, 59% focused on the "cell-transplantation" strategy, 82% used in vitro experimentation, 58% in vivo animal models and only one described an in vivo in situ human clinical study. 87% used dental pulp stem cells. A majority of the studies reported histology (75%) and immunohistochemistry explorations (66%). 73% mentioned the use of cytotoxicity, proliferation or viability tests. 48% took vascularization into account but only 6% studied the antibacterial properties of the scaffolds. This article gives an overview of the methods used to regenerate dental pulp from stem cells and should help researchers create the best development strategies for research in this field.

Integrated bioelectronic proton-gated logic elements utilizing nanoscale patterned Nafion

A central endeavour in bioelectronics is the development of logic elements to transduce and process ionic to electronic signals. Motivated by this challenge, we report fully monolithic, nanoscale logic elements featuring n- and p-type nanowires as electronic channels that are proton-gated by electron-beam patterned Nafion. We demonstrate inverter circuits with state-of-the-art ion-to-electron transduction performance giving DC gain exceeding 5 and frequency response up to 2 kHz. A key innovation facilitating the logic integration is a new electron-beam process for patterning Nafion with linewidths down to 125 nm. This process delivers feature sizes compatible with low voltage, fast switching elements. This expands the scope for Nafion as a versatile patternable high-proton-conductivity element for bioelectronics and other applications requiring nanoengineered protonic membranes and electrodes.