Surface Ocean Biogeochemistry Regulates the Impact of Anthropogenic Aerosol Fe Deposition on the Cycling of Iron and Iron Isotopes in the North Pacific.

Distinctively-light isotopic signatures associated with Fe released from anthropogenic activity have been used to trace basin-scale impacts. However, this approach is complicated by the way Fe cycle processes modulate oceanic dissolved Fe (dFe) signatures (δ56Fediss) post deposition. Here we include dust, wildfire, and anthropogenic aerosol Fe deposition in a global ocean biogeochemical model with active Fe isotope cycling, to quantify how anthropogenic Fe impacts surface ocean dFe and δ56Fediss. Using the North Pacific as a natural laboratory, the response of dFe, δ56Fediss, and primary productivity are spatially and seasonally variable and do not simply follow the footprint of atmospheric deposition. Instead, the effect of anthropogenic Fe is regulated by the biogeochemical regime, specifically the degree of Fe limitation and rates of primary production. Overall, we find that while δ56Fediss does trace anthropogenic input, the response is muted by fractionation during phytoplankton uptake, but amplified by other isotopically-light Fe sources.

Constraints on the Cycling of Iron Isotopes From a Global Ocean Model.

Although iron (Fe) is a key regulator of primary production over much of the ocean, many components of the marine iron cycle are poorly constrained, which undermines our understanding of climate change impacts. In recent years, a growing number of studies (often part of GEOTRACES) have used Fe isotopic signatures (δ56Fe) to disentangle different aspects of the marine Fe cycle. Characteristic δ56Fe endmembers of external sources and assumed isotopic fractionation during biological Fe uptake or recycling have been used to estimate relative source contributions and investigate internal transformations, respectively. However, different external sources and fractionation processes often overlap and act simultaneously, complicating the interpretation of oceanic Fe isotope observations. Here we investigate the driving forces behind the marine dissolved Fe isotopic signature (δ56Fediss) distribution by incorporating Fe isotopes into the global ocean biogeochemical model PISCES. We find that distinct external source endmembers acting alongside fractionation during organic complexation and phytoplankton uptake are required to reproduce δ56Fediss observations along GEOTRACES transects. δ56Fediss distributions through the water column result from regional imbalances of remineralization and abiotic removal processes. They modify δ56Fediss directly and transfer surface ocean signals to the interior with opposing effects. Although attributing crustal compositions to sedimentary Fe sources in regions with low organic carbon fluxes improves our isotope model, δ56Fediss signals from hydrothermal or sediment sources cannot be reproduced accurately by simply adjusting δ56Fe endmember values. This highlights that additional processes must govern the exchange and/or speciation of Fe supplied by these sources to the ocean.

An oral health optimized diet can reduce gingival and periodontal inflammation in humans - a randomized controlled pilot study.

BACKGROUND: The aim of this pilot study was to investigate the effects of four weeks of an oral health optimized diet on periodontal clinical parameters in a randomized controlled trial. METHODS: The experimental group (n = 10) had to change to a diet low in carbohydrates, rich in Omega-3 fatty acids, and rich in vitamins C and D, antioxidants and fiber for four weeks. Participants of the control group (n = 5) did not change their dietary behavior. Plaque index, gingival bleeding, probing depths, and bleeding upon probing were assessed by a dentist with a pressure-sensitive periodontal probe. Measurements were performed after one and two weeks without a dietary change (baseline), followed by a two week transitional period, and finally performed weekly for four weeks. RESULTS: Despite constant plaque values in both groups, all inflammatory parameters decreased in the experimental group to approximately half that of the baseline values (GI: 1.10 ± 0.51 to 0.54 ± 0.30; BOP: 53.57 to 24.17 %; PISA: 638 mm(2) to 284 mm(2)). This reduction was significantly different compared to that of the control group. CONCLUSION: A diet low in carbohydrates, rich in Omega-3 fatty acids, rich in vitamins C and D, and rich in fibers can significantly reduce gingival and periodontal inflammation. TRIAL REGISTRATION: German Clinical Trials Register; https://www.germanctr.de (DRKS00006301). Registered on 2015-02-21.

Pupillary response to percutaneous auricular vagus nerve stimulation in alcohol withdrawal syndrome: A pilot trial.

BACKGROUND: Autonomic symptoms in alcohol withdrawal syndrome (AWS) are associated with a sympathetic-driven imbalance of the autonomic nervous system. To restore autonomic balance in AWS, novel neuromodulatory approaches could be beneficial. We conducted a pilot trial with percutaneous auricular vagus nerve stimulation (pVNS) in AWS and hypothesized that pVNS will enhance the parasympathetic tone represented by a reduction of pupillary dilation in a parasympatholytic pharmacological challenge. METHODS: Thirty patients suffering from alcohol use disorder, undergoing AWS, and stable on medication, were recruited in this open-label, single-arm pilot trial with repeated-measure design. Peripheral VNS (monophasic volt impulses of 1 msec, alternating polarity, frequency 1 Hz, amplitude 4 mV) was administered at the left cymba conchae for 72 h, followed by pupillometry under a tropicamide challenge. We assessed craving with a visual analog scale. We used pupillary mean as the dependent variable in a repeated-measures ANOVA (rmANOVA). RESULTS: A repeated-measures ANOVA resulted in a significant difference for pupillary diameter across time and condition (F(2,116) = 27.97, p < .001, ηp2 > .14). Tukey-adjusted post hoc analysis revealed a significant reduction of pupillary diameter after pVNS. Alcohol craving was significantly reduced after pVNS (p < .05, Cohen's d = 1.27). CONCLUSION: Our study suggests that pVNS activates the parasympathetic nervous system in patients with acute AWS, and that this activation is measurable by pupillometry. To this end, pVNS could be beneficial as a supportive therapy for AWS. Potential confounding effects of anti-craving treatment should be kept in mind.

Detecting Mandible Fractures in CBCT Scans Using a 3-Stage Neural Network.

After nasal bone fractures, fractures of the mandible are the most frequently encountered injuries of the facial skeleton. Accurate identification of fracture locations is critical for effectively managing these injuries. To address this need, JawFracNet, an innovative artificial intelligence method, has been developed to enable automated detection of mandibular fractures in cone-beam computed tomography (CBCT) scans. JawFracNet employs a 3-stage neural network model that processes 3-dimensional patches from a CBCT scan. Stage 1 predicts a segmentation mask of the mandible in a patch, which is subsequently used in stage 2 to predict a segmentation of the fractures and in stage 3 to classify whether the patch contains any fracture. The final output of JawFracNet is the fracture segmentation of the entire scan, obtained by aggregating and unifying voxel-level and patch-level predictions. A total of 164 CBCT scans without mandibular fractures and 171 CBCT scans with mandibular fractures were included in this study. Evaluation of JawFracNet demonstrated a precision of 0.978 and a sensitivity of 0.956 in detecting mandibular fractures. The current study proposes the first benchmark for mandibular fracture detection in CBCT scans. Straightforward replication is promoted by publicly sharing the code and providing access to JawFracNet on grand-challenge.org.

Neoadjuvant treatment does not influence PD-L1 expression in stage III non-small-cell lung cancer: a retrospective analysis of tumor samples from the trials SAKK 16/96, 16/00, 16/01, and 16/14.

BACKGROUND: The inclusion of immune checkpoint inhibitors (ICIs) in the treatment of operable stage III non-small-cell lung cancer is becoming a new standard. Programmed death-ligand 1 (PD-L1) protein expression on tumor cells has emerged as the most important biomarker for sensitivity to ICIs targeting the programmed cell death protein 1 (PD-1)-PD-L1 axis. Little is known about the impact of neoadjuvant treatment on PD-L1 expression. PATIENTS AND METHODS: We assessed PD-L1 expression by immunohistochemistry (Ventana SP263 assay) on tumor cells in treatment-naive diagnostic tumor samples and matched lung resections from patients with stage III non-small-cell lung cancer included in the Swiss Group for Clinical Cancer Research (SAKK) trials 16/96, 16/00, 16/01, and 16/14. All patients received neoadjuvant chemotherapy (CT) with cisplatin/docetaxel, either as single modality (CT), with sequential radiotherapy [chemoradiation therapy (CRT)] or with the PD-L1 inhibitor durvalumab (CT + ICI). RESULTS: Overall, 132 paired tumor samples were analyzed from patients with neoadjuvant CT (n = 69), CRT (n = 33) and CT + ICI (n = 30). For CT and CRT, PD-L1 expression before and after neoadjuvant treatment did not differ significantly (Wilcoxon test, P = 0.94). Likewise, no statistically significant difference was observed between CT and CRT for PD-L1 expression after neoadjuvant treatment (P = 0.97). For CT + ICI, PD-L1 expression before and after neoadjuvant treatment also did not differ significantly (Wilcoxon test, P > 0.99). Event-free survival and overall survival for patients with downregulation or upregulation of PD-L1 expression after neoadjuvant treatment were similar. CONCLUSIONS: In our cohort of patients neoadjuvant treatment did not influence PD-L1 expression, irrespective of the specific neoadjuvant treatment protocol. Dynamic change of PD-L1 expression did not correlate with event-free survival or overall survival.

Hypogonadism and anemia in an athlete.

We report the case of a highly trained endurance athlete (22-year-old) who developed anemia (Hb 9.5 mg/dl) over a period of 6 months. Iron deficient or haemolytic anemia, as well as chronic loss of blood, were excluded. Further, laboratory analyses revealed that this athlete exhibited very low levels of testosterone due to a partial hypogonadotropic hypogonadism. Following testosterone supplementation, red blood cell indices improved. Although hypogonadotropic hypogonadism is well known to be associated with reduced hematopoesis, it rarely causes anemia in athletes. This should be considered as a possible cause for anemia. Extreme training, unbalanced nutrition or the combination of both, have been shown to be causally involved in the development of secondary hypogonadotropic hypogonadism.

[Physical exercise as treatment of type 2 diabetes mellitus]. / Bewegung als Therapie bei Diabetes mellitus Typ 2.

The beneficial role of physical exercise on glycemic control in patients with type 2 diabetes mellitus has been confirmed by several controlled trials including both aerobic and resistance exercise protocols. Exercise has been shown to increase insulin sensitivity, lower blood sugar levels, reduce body fat and improve physical fitness. Grade A scientific evidence has been assigned to the effect of regular physical activity on glycemic control for both endurance and resistance exercise.The recommendations for endurance exercise are: aerobic physical activity of moderate intensity (40-60% of VO(2)max or 50-70% of maximum heart rate) for at least 150 min/week and/or at least 90 min/week of vigorous aerobic exercise (> 60% of VO(2)max or > 70% of maximum heart rate). The physical activity should be distributed over at least 3 days/week and with no more than 2 consecutive days without physical activity. The recommendations for resistance exercise are: resistance exercise should be performed at least 3 times a week, including all major muscle groups, progressing to 3 sets of 8-10 repetitions at a weight that cannot be lifted > 8-10 times.

Targeting immunoliposomes to EGFR-positive glioblastoma.

BACKGROUND: We assessed the capacity of epidermal growth factor receptor (EGFR)-targeted immunoliposomes to deliver cargo to brain tumor tissue in patients with relapsed glioblastoma harboring an EGFR amplification. We aimed to assess the tolerability and effectiveness of anti-EGFR immunoliposomes loaded with doxorubicin (anti-EGFR ILs-dox) in glioblastoma multiforme patients. PATIENTS AND METHODS: Patients with EGFR-amplified, relapsed glioblastoma were included in this phase I pharmacokinetic trial. Patients received up to four cycles of anti-EGFR ILs-dox. Twenty-four hours later, plasma and cerebrospinal fluid (CSF) samples were obtained. In addition, we also treated three patients with anti-EGFR ILs-dox before resection of their relapsed glioblastoma. Doxorubicin concentrations were measured in plasma, CSF, and tumor tissue. Safety and efficacy parameters were also obtained. RESULTS: There were no or negligible levels of doxorubicin found in the CSF demonstrating that anti-EGFR ILs-dox are not able to cross the blood-brain barrier (BBB). However, significant levels were detected in glioblastoma tissue 24 h after the application, indicating that the disruption of BBB integrity present in high-grade gliomas might enable liposome delivery into tumor tissue. No new safety issues were observed. The median progression-free survival was 1.5 months and the median overall survival was 8 months. One patient undergoing surgery had a very long remission suggesting that neoadjuvant administration may have a positive effect on outcome. CONCLUSIONS: We clearly demonstrate that anti-EGFR-immunoliposomes can be targeted to EGFR-amplified glioblastoma and cargo-in this case doxorubicin-can be delivered, although these immunoliposomes do not cross the intact BBB. (The GBM-LIPO trial was registered as NCT03603379).

Long-term outcomes of operable stage III NSCLC in the pre-immunotherapy era: results from a pooled analysis of the SAKK 16/96, SAKK 16/00, SAKK 16/01, and SAKK 16/08 trials.

BACKGROUND: Chemoradiotherapy with durvalumab consolidation has yielded excellent results in stage III non-small-cell lung cancer (NSCLC). Therefore, it is essential to identify patients who might benefit from a surgical approach. MATERIAL AND METHODS: Data from 437 patients with operable stage III NSCLC enrolled in four consecutive Swiss Group for Clinical Cancer Research (SAKK) trials (16/96, 16/00, 16/01, 16/08) were pooled and outcomes were analyzed in 431 eligible patients. All patients were treated with three cycles of induction chemotherapy (cisplatin/docetaxel), followed in some patients by neoadjuvant radiotherapy (44 Gy, 22 fractions) (16/00, 16/01, 16/08) and cetuximab (16/08). RESULTS: With a median follow-up time of 9.3 years (range 8.5-10.3 years), 5- and 10-year overall survival (OS) rates were 37% and 25%, respectively. Overall, 342 patients (79%) underwent tumor resection, with a complete resection (R0) rate of 80%. Patients (n = 272, 63%) with R0 had significantly longer OS compared to patients who had surgery but incomplete resection (64.8 versus 19.2 months, P < 0.001). OS for patients who achieved pathological complete remission (pCR) (n = 66, 15%) was significantly better compared to resected patients without pCR (86.5 versus 37.0 months, P = 0.003). For patients with pCR, the 5- and 10-year event-free survival and OS rates were 45.7% [95% confidence interval (CI) 32.8% to 57.7%] and 28.1% (95% CI 15.2% to 42.6%), and 58.2% (95% CI 45.2% to 69.2%) and 45.0% (95% CI 31.5% to 57.6%), respectively. CONCLUSION: We report favorable long-term outcomes in patients with operable stage III NSCLC treated with neoadjuvant chemotherapy with cisplatin and docetaxel ± neoadjuvant sequential radiotherapy from four prospective SAKK trials. Almost two-third of the patients underwent complete resection after neoadjuvant therapy. We confirm R0 resection and pCR as important predictors of outcome.

[Computer-assisted joint replacement surgery]. / Navigation in der Endoprothetik.

Wrong alignment of hip and knee prosthesis is a known risk factor for early loosening and revision. Meta-analyses have shown that, by use of computer navigation, outliers can be reduced significantly. Our analysis of 200 implanted knee prostheses (100 navigated procedures, 100 conventional procedures) and 60 implanted hip resurfacings (30 navigated procedures, 30 conventional procedures) yielded the same result: In total knee arthroplasty and hip resurfacing, the numbers of outliers were significantly reduced by use of computer navigation. Furthermore, in total knee arthroplasty a significantly reduced blood loss and need for blood transfusions were noted if computer navigation was used. Long term studies are required to verify if computer navigation may be an economically cost-saving procedure. So far, in our clinic every navigated operation produced extra costs of 442 Euros. In our current healthcare system no reimbursement for these additional charges exist.

Seasonality in schizophrenia-An analysis of a nationwide registry with 110,735 hospital admissions.

BACKGROUND: Seasonal patterns in hospitalizations have been observed in various psychiatric disorders, however, it is unclear whether they also exist in schizophrenia. Previous studies found mixed results and those reporting the presence of seasonality differ regarding the characteristics of these patterns. Further, they are inconclusive whether sex is an influencing factor. The aim of this study was therefore to examine if seasonal patterns in hospitalizations can be found in schizophrenia, with special regard to a possible influence of sex, by using a large national dataset. METHODS: Data on all hospital admissions within Austria due to schizophrenia (F20.0-F20.6) for the time period of 2003-2016 were included. Age standardized monthly variation of hospitalization for women and men was analyzed and the level of significance adjusted for multiple testing. RESULTS: The database comprised of 110,735 admissions (59.6% men). Significant seasonal variations were found in the total sample with hospitalization peaks in January and June and a trough in December (p < 0.0001). No significant difference in these patterns was found between women and men with schizophrenia (p < 0.0001). CONCLUSION: Our study shows that schizophrenia-related hospitalizations follow a seasonal pattern in both men and women. The distribution of peaks might be influenced by photoperiod changes which trigger worsening of symptoms and lead to exacerbations in schizophrenia. Further research is necessary to identify underlying factors influencing seasonal patterns and to assess whether a subgroup of patients with schizophrenia is especially vulnerable to the impact of seasonal variations.

How accurate is image-free computer navigation for hip resurfacing arthroplasty? An anatomical investigation.

BACKGROUND: The existing studies concerning image-free navigated implantation of hip resurfacing arthroplasty are based on analysis of the accuracy of conventional biplane radiography. Studies have shown that these measurements in biplane radiography are imprecise and that precision is improved by use of three-dimensional (3D) computer tomography (CT) scans. To date, the accuracy of image-free navigation devices for hip resurfacing has not been investigated using CT scans, and anteversion accuracy has not been assessed at all. Furthermore, no study has tested the reliability of the navigation software concerning the automatically calculated implant position. The purpose of our study was to analyze the accuracy of varus-valgus and anteversion using an image-free hip resurfacing navigation device. The reliability of the software-calculated implant position was also determined. METHODS: A total of 32 femoral hip resurfacing components were implanted on embalmed human femors using an image-free navigation device. In all, 16 prostheses were implanted with the proposed position generated by the navigation software; the 16 prostheses were inserted in an optimized valgus position. A 3D CT scan was undertaken before and after operation. RESULTS: The difference between the measured and planned varus-valgus angle averaged 1 degrees (mean +/- SD: group I, 1 degrees +/- 2 degrees ; group II, 1 degrees +/- 1 degrees ). The mean +/- SD difference between femoral neck anteversion and anteversion of the implant was 4 degrees (group I, 4 degrees +/- 4 degrees ; group II, 4 degrees +/- 3 degrees ). The software-calculated implant position differed 7 degrees +/- 8 degrees from the measured neck-shaft angle. These measured accuracies did not differ significantly between the two groups. CONCLUSIONS: Our study proved the high accuracy of the navigation device concerning the most important biomechanical factor: the varus-valgus angle. The software calculation of the proposed implant position has been shown to be inaccurate and needs improvement. Hence, manual adjustment of the implant position in the software-planning step is frequently required.

Imageless navigation of hip resurfacing arthroplasty increases the implant accuracy.

Surface arthroplasty of the hip is increasingly popular. Optimising the position of the femoral component is essential to avoid early implant failures such as femoral neck fractures. Sixty hip surface replacements were retrospectively analysed. In 30 patients imageless navigation was used, and 30 patients were operated upon using conventional jigs. Accuracy, implant position, operating time, and complications have been recorded. The navigation device improved the implant position with high accuracy. Implant-shaft angles <130 degrees and uncovered cancellous bone of the superior femoral neck could be safely avoided. After a significant learning curve, navigation took 15 minutes longer than conventional implantation. No complications were found in either group. Computer-assisted navigation allowed accurate implantation of the femoral component avoiding pitfalls of hip surface replacement. From our point of view the optimal placement of the femoral component outweighs the disadvantage of a longer operating time.

[Injuries to the upper limbs in competitive wrestlers]. / Verletzungen der oberen Extremitäten bei Ringern im Hochleistungssport.

Great variety of tackling and defence in wrestling in standing position and on the floor cannot be compared to other kind of sports. High demand to motoric characteristics and tournament specific movability is required. However wrestling in Germany belongs to a fringe sport there is an increase of professionality. This leads to a sufficient and high-demanded supervision. Aim of this retrospective study was to evaluate sport injuries using a questionnaire and to figure out a correlation between kind and frequency of sport injuries of different body regions. 163 questionnaires out of 200 had been evaluated. In the region of the upper limb injuries had been found in 23%. The injury rate was higher in the athletes wrestling in the 2nd league. Wrestling is a technically and tactically ambitious sport. Injuries should be evaluated very careful to minimize the risk changing tactics and training methods.

Synthesis, optical properties and theoretical modelling of discrete emitting states in doped silicon nanocrystals for bioimaging.

The creation of multiple emission pathways in quantum dots (QDs) is an exciting prospect with fundamental interest and optoelectronic potential. For the first time, we report multiple emission pathways in semiconductor nanocrystals (NCs) where the number of emission pathways desired is controlled by the number of dopant atoms per quantum dot. The origin of additional emission pathways is explained by interactions between dopant states and NC energy levels. Density functional theory (DFT) calculations of undoped 2.3 nm silicon (Si NCs) and the same NCs doped with 2 interstitial Cu atoms show good agreement to experiment. Such calculations provide valuable data to explain the changes in optical transitions due to the Cu dopant in terms of transition energies, quantum yield and dopant position as a function of dopants per NC. Changes in the optical properties of Si NCs induced by dopant concentration include extended excitation range and enhanced absorption coefficients, emission redshifts of up to 60 nm, and a two-fold increase in quantum yields up to 22%. The optical properties of doped NCs lead to significant bioimaging improvements illustrated by in vitro cell imaging, including redshifted excitation wavelengths away from natural autofluorescence and enhanced fluorescent signals.

[Students evaluation of a sports-orthopaedic and sports-traumatological course in theory and practice]. / Evaluierung eines sportorthopädisch-sporttraumatologischen Studentenkurses in Seminar- und Praxisform.

Sports traumatology and sports orthopaedics are two closely interconnected fields usually more or less non-existent in a medical curriculum. Optional courses are difficult to coordinate because of the densely packed course schedule of a medical student, although the overall interest in it shows a continually upward trend. The course that is being offered since the winter semester 2004 / 2005 has been conceived as a seminar with lectures on a variety of subjects but it contains a practical part as well, e. g. for improving examination techniques. The offered course is particularly aimed at students of higher clinical semesters. The evaluation was carried out using questionnaires that were designed especially for this purpose. Subject to evaluation were not only general topics, but also the course instructors who had participated in the theoretical and practical implementation of the course. Suggestions for improvement or other comments were encouraged and taken into consideration. A total of 116 medical students (m = 68, f = 48) who have taken the course since the winter semester 2004 / 2005 have answered the questionnaire for the present evaluation. The interdisciplinary topics, covered the theoretical as well as the practical ones, were considered as interesting and important by 90 % of the students, organization and commitment on the part of the instructors were largely commended. Additional training in sports orthopaedics and sports traumatology enjoys great popularity on the part of medical students, in spite of their densely packed course schedule. Especially its multidisciplinary orientation provides students with a general overview in sports orthopaedics and sports traumatology and raises further interest in both fields of study.

[Interspinous decompression as treatment for lumbar spinal stenosis]. / Interspinöse Dekompression als Therapie der lumbalen Spinalkanalstenose.

Interspinous process distractors are an effective operative tool for treating patients with lumbar spinal stenosis. Lumbar stenosis with minor secondary instabilities due to degenerative changes in the segment can also be treated successfully with these devices. In case of failure, these devices can easily be revised or removed. As this operative procedure is not very time-consuming, it is a reasonable option for elderly patients with various medical problems and increased anaesthetic risk. There are reports of implanting these devices in certain cases under local anaesthetic. A prospective randomised trial has shown promising results for up to two years postoperatively. There are no long-term results available.

Evaluation of [Formula: see text] enrichment values obtained with an oral breath test under conditions of impaired gastric functioning.

Gastric emptying can be assessed by an oral administration of a 13C labeled substrate and its response in the expiratory release of the oxidation product [Formula: see text]. Impaired gut function, reflected, for example, in an intolerance against enteral nutrition may delay or discontinue gastric emptying, potentially leading to multiple peaks in the time profile of expiration. The resulting profile cannot be analyzed by the usual data evaluation that is based on a 'beta exponential' (BEX) function. We developed a new approach that better reflects the underlying physiology. It allows a flexible time profile of gastric release and considers a transient [Formula: see text] retention in different compartments as well as an incomplete recovery of [Formula: see text] in the expiration. Parameters that describe the distribution/retention kinetics cannot be determined based on the same breath data that were used to estimate emptying. To enable the determination of the kinetic parameters, they were constrained to match published data using a Bayesian statistical analysis. The applicability of the new model was compared with BEX for healthy subjects. BEX fails to explain the observed data and, compared to the new approach, overestimates the speed of emptying. Predictive accuracy under impaired gastric motility was explored using synthetic data. Only the new approach can reproduce a multiphase absorption profile. When routine benchtop equipment was used for measurements, then the rate-limiting step for precision in the estimate of emptying is the quality in the a priori estimate for kinetic parameters rather than precision in measurements. Only about 80% of the absorbed [Formula: see text] has to be released by expiration. With these features, the new approach promises to widen the applicability of breath tests for gastric emptying.