Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 346
Filter
1.
Ophthalmologie ; 121(7): 554-564, 2024 Jul.
Article in German | MEDLINE | ID: mdl-38801461

ABSTRACT

PURPOSE: In recent years artificial intelligence (AI), as a new segment of computer science, has also become increasingly more important in medicine. The aim of this project was to investigate whether the current version of ChatGPT (ChatGPT 4.0) is able to answer open questions that could be asked in the context of a German board examination in ophthalmology. METHODS: After excluding image-based questions, 10 questions from 15 different chapters/topics were selected from the textbook 1000 questions in ophthalmology (1000 Fragen Augenheilkunde 2nd edition, 2014). ChatGPT was instructed by means of a so-called prompt to assume the role of a board certified ophthalmologist and to concentrate on the essentials when answering. A human expert with considerable expertise in the respective topic, evaluated the answers regarding their correctness, relevance and internal coherence. Additionally, the overall performance was rated by school grades and assessed whether the answers would have been sufficient to pass the ophthalmology board examination. RESULTS: The ChatGPT would have passed the board examination in 12 out of 15 topics. The overall performance, however, was limited with only 53.3% completely correct answers. While the correctness of the results in the different topics was highly variable (uveitis and lens/cataract 100%; optics and refraction 20%), the answers always had a high thematic fit (70%) and internal coherence (71%). CONCLUSION: The fact that ChatGPT 4.0 would have passed the specialist examination in 12 out of 15 topics is remarkable considering the fact that this AI was not specifically trained for medical questions; however, there is a considerable performance variability between the topics, with some serious shortcomings that currently rule out its safe use in clinical practice.


Subject(s)
Educational Measurement , Ophthalmology , Specialty Boards , Ophthalmology/education , Educational Measurement/methods , Educational Measurement/standards , Germany , Humans , Clinical Competence/standards , Certification , Artificial Intelligence
2.
Child Adolesc Psychiatry Ment Health ; 16(1): 55, 2022 Jun 28.
Article in English | MEDLINE | ID: mdl-35765005

ABSTRACT

BACKGROUND: The purpose of this study was to evaluate the self-reported stability of psychopathic traits in adolescents in residential care (both child welfare and juvenile justice placed juveniles) and potential influencing factors. METHODS: We applied the Youth Psychopathic traits Inventory (YPI) in a sample of 162 adolescents (M = 15.0 years, SD = 1.3) over a mean time interval of 11 months (min. 6, max. 21 months, SD = 3.14). RESULTS: There was no significant difference in YPI total score nor in the three underlying dimensions Grandiose-Manipulative (GM), Callous-Unemotional (CU), and Impulsive-Irresponsible (II) between t1 and t2. Furthermore, approximately 70% of the adolescents showed no clinically significant reliable change on the YPI total score (as measured with the reliable change index), 15% improved, 15% deteriorated. The strongest predictor for psychopathic traits at t2 were psychopathic traits at t1. Additional predictors for higher levels of general psychopathic traits was male sex, for CU-traits male sex and lower levels of internalizing mental health problems, and for II-traits higher levels of externalizing mental health problems. Generally, the three reliable change groups (increase, no change, decrease) did not seemed to differ on relevant factors. CONCLUSIONS: Our results add to the findings that psychopathic traits are relatively stable in this at-risk group over approximately a 1-year time interval. Research with a longer follow-up time and more time points is warranted to better interpret these results.

3.
J Hosp Infect ; 126: 109-115, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35623469

ABSTRACT

BACKGROUND: Wide variation in mortality rates among critically ill patients with coronavirus disease 2019 (COVID-19) has been reported. This study evaluated whether healthcare-associated infections (HAI) are a risk factor for death among patients with severe COVID-19 in the intensive care unit (ICU). METHODS: This retrospective cohort study included patients with severe COVID-19 hospitalized in the ICU of four hospitals in the city of Curitiba, Brazil. Patients with COVID-19 who died during ICU hospitalization were compared with those who were discharged. A second analysis compared patients who developed HAI in the ICU with those who did not. Multiple logistic regression models were used to control for confounders. RESULTS: In total, 400 patients were included, and 123 (31%) patients developed HAI. The most common HAI was lower respiratory tract infection (67%). Independent risk factors for death were: age [odds ratio (OR) 1.75, 95% confidence interval (CI) 1.43-2.15; P<0.0001]; clinical severity score (OR 2.21, 95% CI 1.70-2.87; P<0.0001); renal replacement therapy (OR 12.8, 95% CI 5.78-28.6; P<0.0001); and HAI (OR 5.9, 95% CI 3.31-10.5; P<0.0001). A longer interval between symptom onset and hospital admission was protective against death (OR 0.93, 95% CI 0.88-0.98; P=0.017). The only independent factors associated with HAI were high C-reactive protein and low PaO2/FiO2 ratio. CONCLUSIONS: No factors that could point to a high-risk group for HAI acquisition were identified. However, age, dialysis and HAI increased the risk of death in ICU patients with severe COVID-19; of these, HAI is the only preventable risk factor.


Subject(s)
COVID-19 , Cross Infection , Delivery of Health Care , Humans , Intensive Care Units , Renal Dialysis , Retrospective Studies , Risk Factors
4.
Phys Rev B ; 103(1)2021 Jan.
Article in English | MEDLINE | ID: mdl-38486881

ABSTRACT

We investigate the magnetic properties of LiYbO2, containing a three-dimensionally frustrated, diamond-like lattice via neutron scattering, magnetization, and heat capacity measurements. The stretched diamond network of Yb3+ ions in LiYbO2 enters a long-range incommensurate, helical state with an ordering wave vector k=(0.384,±0.384,0) that "locks-in" to a commensurate k=(1/3,±1/3,0) phase under the application of a magnetic field. The spiral magnetic ground state of LiYbO2 can be understood in the framework of a Heisenberg J1-J2 Hamiltonian on a stretched diamond lattice, where the propagation vector of the spiral is uniquely determined by the ratio of J2/J1. The pure Heisenberg model, however, fails to account for the relative phasing between the Yb moments on the two sites of the bipartite lattice, and this detail as well as the presence of an intermediate, partially disordered, magnetic state below 1 K suggests interactions beyond the classical Heisenberg description of this material.

5.
Z Angew Math Phys ; 71(6): 201, 2020.
Article in English | MEDLINE | ID: mdl-33244190

ABSTRACT

We prove existence and uniqueness of a solution to the Cauchy problem corresponding to the dynamics capillarity equation ∂ t u ε , δ + div f ε , δ ( x , u ε , δ ) = ε Δ u ε , δ + δ ( ε ) ∂ t Δ u ε , δ , x ∈ M , t ≥ 0 u | t = 0 = u 0 ( x ) . Here, f ε , δ and u 0 are smooth functions while ε and δ = δ ( ε ) are fixed constants. Assuming f ε , δ → f ∈ L p ( R d × R ; R d ) for some 1 < p < ∞ , strongly as ε → 0 , we prove that, under an appropriate relationship between ε and δ ( ε ) depending on the regularity of the flux f , the sequence of solutions ( u ε , δ ) strongly converges in L loc 1 ( R + × R d ) toward a solution to the conservation law ∂ t u + div f ( x , u ) = 0 . The main tools employed in the proof are the Leray-Schauder fixed point theorem for the first part and reduction to the kinetic formulation combined with recent results in the velocity averaging theory for the second. These results have the potential to generate a stable semigroup of solutions to the underlying scalar conservation laws different from the Kruzhkov entropy solutions concept.

6.
Bone Joint J ; 101-B(9): 1138-1143, 2019 09.
Article in English | MEDLINE | ID: mdl-31474148

ABSTRACT

AIMS: The aim of this study was to compare the incidence of anterior knee pain after antegrade tibial nailing using suprapatellar and infrapatellar surgical approaches. PATIENTS AND METHODS: A total of 95 patients with a tibial fracture requiring an intramedullary nail were randomized to treatment using a supra- or infrapatellar approach. Anterior knee pain was assessed at four and six months, and one year postoperatively, using the Aberdeen Weightbearing Test - Knee (AWT-K) score and a visual analogue scale (VAS) score for pain. The AWT-K is an objective patient-reported outcome measure that uses weight transmitted through the knee when kneeling as a surrogate for anterior knee pain. RESULTS: A total of 53 patients were randomized to a suprapatellar approach and 42 to an infrapatellar approach. AWT-K results showed a greater mean proportion of weight transmitted through the injured leg compared with the uninjured leg when kneeling in the suprapatellar group compared with the infrapatellar group at all timepoints at all follow-up visits. This reached significance at four months for all timepoints except 30 seconds. It also reached significance at six months at 0 seconds, and for one year at 60 seconds. CONCLUSION: The suprapatellar surgical approach for antegrade tibial nailing is associated with less anterior knee pain postoperatively compared with the infrapatellar approach Cite this article: Bone Joint J 2019;101-B:1138-1143.


Subject(s)
Arthralgia/prevention & control , Fracture Fixation, Intramedullary/adverse effects , Fracture Fixation, Intramedullary/methods , Pain, Postoperative/prevention & control , Patella/surgery , Tibial Fractures/surgery , Adolescent , Adult , Aged , Arthralgia/etiology , Bone Nails/adverse effects , Female , Fracture Fixation, Intramedullary/instrumentation , Humans , Knee/surgery , Knee Joint/surgery , Male , Middle Aged , Pain, Postoperative/etiology , Patient Reported Outcome Measures , Tibia/injuries , Tibia/surgery , Young Adult
7.
J Magn Reson ; 297: 33-41, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30347386

ABSTRACT

For studying electrode and electrolyte materials for lithium ion batteries, solid-state (SS) nuclear magnetic resonance (NMR) of lithium moves into focus of current research. Theoretical simulations of magnetic resonance parameters facilitate the analysis and interpretation of experimental Li SS-NMR spectra and provide unique insight into physical and chemical processes that are determining the spectral profile. In the present paper, the accuracy and reliability of the theoretical simulation methods of Li chemical shielding values is benchmarked by establishing a reference scale for Li SS-NMR of diamagnetic compounds. The impact of geometry, ionic mobility and relativity are discussed. Eventually, the simulation methods are applied to the more complex lithium titanate spinel (Li4Ti5O12, LTO), which is a widely discussed battery anode material. Simulation of the Li SS-NMR spectrum shows that the commonly adopted approach of assigning the resonances to individual crystallographic sites is not unambiguous.

8.
J Magn Reson ; 294: 133-142, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30041071

ABSTRACT

Li10GeP2S12 (LGPS) is the fastest known Li-ion conductor to date due to the formation of one-dimensional channels with a very high Li mobility. A knowledge-based optimization of such materials for use, for example, as solid electrolyte in all-solid-state batteries requires, however, a more comprehensive understanding of Li ion conduction that considers mobility in all three dimensions, mobility between crystallites and different phases, as well as their distributions within the material. The spin alignment echo (SAE) nuclear magnetic resonance (NMR) technique is suitable to directly probe slow Li ion hops with correlation times down to about 10-5 s, but distinction between hopping time constants and relaxation processes may be ambiguous. This contribution presents the correlation of the 7Li spin lattice relaxation (SLR) time constants (T1) with the SAE decay time constant τc to distinguish between hopping time constants and signal decay limited by relaxation in the τc distribution. A pulse sequence was employed with two independently varied mixing times. The obtained multidimensional time domain data was processed with an algorithm for discrete Laplace inversion that does not use a non-negativity constraint to deliver 2D SLR-SAE correlation maps. Using the full echo transient, it was also possible to estimate the NMR spectrum of the Li ions responsible for each point in the correlation map. The signal components were assigned to different environments in the LGPS structure.

9.
J Phys Condens Matter ; 30(28): 285701, 2018 Jul 18.
Article in English | MEDLINE | ID: mdl-29790855

ABSTRACT

In this work we study, by means of ab initio calculations, the structural, electronic and magnetic properties of Y-doped BiFeO3 compounds. We determine that there is a morphotropic phase boundary at an yttrium concentration of [Formula: see text], where the structure changes from R3c to Pnma. This structural transition is driven by the chemical pressure induced by the dopant. By analyzing the evolution of the oxygen octahedral tilts we find an enhanced antiferrodistortive distortion when increasing the Y-doping, together with a reduction of the ferroelectric distorsion, that gives rise to a smaller value of the electric polarization. These cooperative effects should lead to a larger canting of the Fe magnetic moments and to a larger ferromagnetic response in the R3c phase, as it is observed in the experiments.

10.
Klin Monbl Augenheilkd ; 233(10): 1115-1119, 2016 Oct.
Article in German | MEDLINE | ID: mdl-27508887

ABSTRACT

The major goal of extraocular muscle surgery for nystagmus is to reduce the abnormal head turn (AHT) which is caused by an eccentric null zone of the nystagmus. Shifting the null zone to the primary gaze position will eliminate the AHT. The Kestenbaum procedure consists of bilateral recession of the yoke muscles opposite to the AHT, combined with bilateral resection or plication of their antagonists. The Anderson procedure is confined to bilateral recession of the yoke muscles and is therefore less invasive. We report on our experience with the Anderson procedure. Patients and Methods: From September 2013 to June 2015, we performed the Anderson procedure in 11 consecutive orthotropic patients with infantile idiopathic or sensory defect nystagmus. Patients responsive to convergence inducing prisms who could benefit from artificial divergence surgery were excluded. Results: Medians and ranges (minimum-maximum) were: Age 7 years (4-30); binocular BCVA 0.5 (0.05-1.0); AHT 30° (20-40); equal recessions on the horizontal yoke muscles opposite to the AHT of 12 mm (10-17), in one case using bovine pericardium grafts. Three (3-6) months post surgery, the AHT was reduced to 7° (0-20). First step success rates, defined by residual AHT ≤ 10° and ≤ 15°, were 73 % (95 % CI 39-93 %) and 82 % (95 % CI 48-97 %). No over-correction or other adverse effects were observed. Two patients later received augmenting surgery. One patient with pre-existing exophoria later required strabismus surgery for exotropia. Conclusion: The AHT can be significantly reduced or completely corrected by the Anderson procedure. Recessions of at least 10 mm on both yoke muscles were performed. The success rates equaled success rates of augmented Kestenbaum surgery. Compared to the latter, the Anderson procedure is less invasive. It is followed by a shorter healing process. It is a vessel sparing method - an advantage for potential future surgery.


Subject(s)
Nystagmus, Pathologic/diagnosis , Nystagmus, Pathologic/surgery , Oculomotor Muscles/surgery , Ophthalmologic Surgical Procedures/methods , Plastic Surgery Procedures/methods , Adolescent , Adult , Child , Child, Preschool , Humans , Male , Treatment Outcome , Young Adult
11.
Nat Commun ; 7: 10852, 2016 Mar 01.
Article in English | MEDLINE | ID: mdl-26927313

ABSTRACT

Recent developments in high-temperature superconductivity highlight a generic tendency of the cuprates to develop competing electronic (charge) supermodulations. While coupled with the lattice and showing different characteristics in different materials, these supermodulations themselves are generally conceived to be quasi-two-dimensional, residing mainly in individual CuO2 planes, and poorly correlated along the c axis. Here we observed with resonant elastic X-ray scattering a distinct type of electronic supermodulation in YBa2Cu3O(7-x) (YBCO) thin films grown epitaxially on La0.7Ca0.3MnO3 (LCMO). This supermodulation has a periodicity nearly commensurate with four lattice constants in-plane, eight out of plane, with long correlation lengths in three dimensions. It sets in far above the superconducting transition temperature and competes with superconductivity below this temperature for electronic states predominantly in the CuO2 plane. Our finding sheds light on the nature of charge ordering in cuprates as well as a reported long-range proximity effect between superconductivity and ferromagnetism in YBCO/LCMO heterostructures.


Subject(s)
Electrochemical Techniques , Lanthanoid Series Elements/chemistry , Copper/chemistry , Electric Conductivity , Magnetic Phenomena , X-Ray Diffraction , Yttrium/chemistry
12.
Ophthalmologe ; 113(6): 514-6, 2016 Jun.
Article in German | MEDLINE | ID: mdl-26502168

ABSTRACT

We report a case of symptomatic ecchordosis physaliphora (EP) in a 34-year-old woman who presented with progressive diplopia due to palsy of the left sixth cranial nerve. Repeated magnetic resonance imaging (MRI) disclosed typical characteristics of a congenital EP lesion with compression of the left abducens nerve presumably because of a secondary herniation of the arachnoid mater. We performed an augmenting combined recess resect procedure on the left eye. No progression of the lesion was observed over a period of 5 years. For differential diagnostics an EP has to be distinguished from skull base tumors, such as chordoma and chondrosarcoma.


Subject(s)
Abducens Nerve Diseases/diagnosis , Abducens Nerve Diseases/surgery , Diplopia/diagnosis , Diplopia/surgery , Hamartoma/diagnosis , Hamartoma/surgery , Abducens Nerve Diseases/etiology , Adult , Diagnosis, Differential , Diplopia/etiology , Female , Hamartoma/complications , Humans , Magnetic Resonance Imaging/methods , Nerve Compression Syndromes/diagnosis , Nerve Compression Syndromes/etiology , Nerve Compression Syndromes/surgery , Treatment Outcome
13.
Geburtshilfe Frauenheilkd ; 75(9): 941-944, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26500371

ABSTRACT

A 54-year-old woman was admitted with a result of high serum estradiol levels (> 4300 pg/ml) and typical postmenopausal symptoms. She had a history of an adnexectomy (normal histopathology) due to the elevated estradiol levels. After surgery, estradiol levels were as high as before. Analyzing the anti-mullerian hormone (AMH), inhibin B, DHEA-S and estrone, typical postmenopausal levels were found. Serum estradiol levels were controlled several times with rabbit-derived polyclonal as well as monoclonal antibodies to optimize the selectivity of the test system. Secondary, a radioimmunoassay was performed to exclude interferences of the detection system where lower, but still elevated estradiol levels (186 pg/ml) were found. Hypothesizing that our patient underwent a cross reaction with irregular antibodies, a control was done using sheep-derived antibodies, which proved a postmenopausal hormone level (estradiol level < 5 pg/ml). This result was confirmed using a fluorescence enzyme immunoassay (FEIA) revealing high levels of irregular antibodies (> 200 mg/l; reference < 30 mg/l). This case depicts the pitfalls of estradiol measurement detecting false elevated estradiol levels in a postmenopausal woman.

14.
Nano Lett ; 15(5): 3431-8, 2015 May 13.
Article in English | MEDLINE | ID: mdl-25928894

ABSTRACT

Ultrathin nanopore membranes based on 2D materials have demonstrated ultimate resolution toward DNA sequencing. Among them, molybdenum disulfide (MoS2) shows long-term stability as well as superior sensitivity enabling high throughput performance. The traditional method of fabricating nanopores with nanometer precision is based on the use of focused electron beams in transmission electron microscope (TEM). This nanopore fabrication process is time-consuming, expensive, not scalable, and hard to control below 1 nm. Here, we exploited the electrochemical activity of MoS2 and developed a convenient and scalable method to controllably make nanopores in single-layer MoS2 with subnanometer precision using electrochemical reaction (ECR). The electrochemical reaction on the surface of single-layer MoS2 is initiated at the location of defects or single atom vacancy, followed by the successive removals of individual atoms or unit cells from single-layer MoS2 lattice and finally formation of a nanopore. Step-like features in the ionic current through the growing nanopore provide direct feedback on the nanopore size inferred from a widely used conductance vs pore size model. Furthermore, DNA translocations can be detected in situ when as-fabricated MoS2 nanopores are used. The atomic resolution and accessibility of this approach paves the way for mass production of nanopores in 2D membranes for potential solid-state nanopore sequencing.

15.
Fortschr Neurol Psychiatr ; 83(5): 276-85, 2015 May.
Article in German | MEDLINE | ID: mdl-26018395

ABSTRACT

OBJECTIVE: In the present study, the German-language version of the Stress Appraisal Measure (SAM) by Peacock and Wong was validated in a student population. SAM is a relatively short questionnaire (28 items) that evaluates a current, stress-triggering event. The theoretical background is provided by the stress model of Lazarus and Folkman. METHOD: 85 students (age: 23; 59 female, 26 male) were exposed to two stress scenarios in order to test whether they were suited to provoke stress. A factor analysis was performed and the internal consistency of the seven SAM scales was determined. In addition, the convergent validity of SAM with State and Trait Anxiety Inventory (STAI), Coping Inventory for Stressful Situations (CISS) and specific emotion scales was investigated via Pearson's product-moment correlation. RESULTS: The two stress scenarios were suited to evoke stress. The factor structure and the internal consistency of the individual scales, as well as the convergent validity of SAM were replicated with minor limitations in the present German version. Some items (especially from the fifth factor) were only replicated partially. CONCLUSION: SAM can also be employed in the German language version.


Subject(s)
Neuropsychological Tests/standards , Stress, Psychological/psychology , Adaptation, Psychological , Anxiety/psychology , Emotions/physiology , Factor Analysis, Statistical , Female , Germany , Humans , Language , Male , Models, Psychological , Reproducibility of Results , Surveys and Questionnaires , Translations , Young Adult
16.
Orthop Traumatol Surg Res ; 101(4): 501-5, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25910703

ABSTRACT

PURPOSE: Distal radius and forearm fractures are injuries that are frequently seen in trauma surgery outpatient clinics. Usually, the wrist is X-rayed in 2 planes as standard diagnostic procedure. In contrast, we evaluate in our study the accuracy of ultrasonography (US) in diagnosing these fractures. METHODS: This prospective study includes the patients who presented at two trauma surgery clinics with a presumptive diagnosis of distal radius or forearm fracture between January and December 2012. After a clinical examination, US imaging of the distal forearm was first carried out on 6 standardized planes followed by radiographs of the wrist made in two planes. The age limit was set at the end of 11 years. RESULTS: In total, 201 patients between 4 and 11 years of age were recruited with an average age of 9.5 years at the time of the trauma. There were 104 (51.7%) fractures distributed as follows: 89 (85.9%) injuries of the distal radius, 9 (8.7%) injuries of the distal ulna, and 6 (5.8%) combined injuries (radius and ulna). Sixty-five greenstick fractures were detected. Surgery was necessary in 34 cases. Specificity and sensitivity of ultrasound diagnosis were 99.5%. CONCLUSION: Ultrasound imaging is suitable to demonstrate fractures of the distal forearm. It is a highly sensitive procedure in detecting distal forearm fractures. In our opinion, a negative result in ultrasound may reduce the need for further radiographs in children with distal forearm lesions. But in any doubtful situation the need for conventional radiographs remains.


Subject(s)
Forearm Injuries/diagnostic imaging , Radius Fractures/diagnostic imaging , Ulna Fractures/diagnostic imaging , Child , Child, Preschool , Female , Humans , Infant , Male , Prospective Studies , Reproducibility of Results , Ultrasonography
17.
Injury ; 46(6): 1074-80, 2015.
Article in English | MEDLINE | ID: mdl-25816704

ABSTRACT

BACKGROUND: During spontaneous vaginal delivery, pubic symphyseal widening is normal. Common changes are reversible after complication-free birth. However, cases of peripartum symphysis separation are rare. There is no consensus in the literature on how to treat pregnancy-related pubic symphysis separation. METHODS: This review used a literature-based search (PubMed, 1900-2013) and analysis of 2 own case reports. Studies with conclusions regarding management were particularly considered. RESULTS: Characteristic symptoms, suprapubic pain and tenderness radiating to the posterior pelvic girdle or lower back, may be noted 48 h after delivery. Pain on movement, especially walking or climbing stairs, is often present. Conservative treatments, such as a pelvic brace with physiotherapy and local interventions such as infiltration, are successful in most cases. Symptom reduction within 6 weeks is the most common outcome, but can take up to 6 months in some cases. Surgical intervention is needed in cases of persistent separation. Anterior plate fixation is offered as a well-known and safe procedure. Minimally invasive SI joint screw fixation is required in cases of combined posterior pelvic girdle lesions. SUMMARY: Postpartum symphyseal rupture can be indicated with the rare occurrence of pelvic pain post-delivery, with sciatica or lumbago and decreased mobility. The diagnosis is made on clinical findings, as well as radiographs of the pelvic girdle. Conservative treatment with a pelvic brace is the gold standard in pre- and postpartum cases of symphysis dysfunction.


Subject(s)
Fracture Fixation, Internal/methods , Obstetric Labor Complications/diagnosis , Pubic Symphysis Diastasis/diagnosis , Pubic Symphysis/injuries , Adult , Bone Screws , Delivery, Obstetric , Female , Humans , Infant, Newborn , Obstetric Labor Complications/pathology , Obstetric Labor Complications/surgery , Peripartum Period , Pregnancy , Pubic Symphysis/pathology , Pubic Symphysis/surgery , Pubic Symphysis Diastasis/pathology , Pubic Symphysis Diastasis/surgery , Risk Factors , Treatment Outcome
18.
Small ; 11(26): 3174-82, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25740328

ABSTRACT

The physicochemical details of the well-established template-assisted electrodeposition process for metal nanowire fabrication are investigated with respect to the physical origination for template geometry limitation. The overall process of metal reduction inside anodized Al2 O3 (AAO) is divided into three parts: i) the electrochemical reduction at the pore bottom, ii) the diffusion of the electrolytic species, and iii) the capacitive interaction between pore surface and electrolyte. The results show that the reduction of Ni is controlled by the degree of electrode recession, i.e., the pore depth. Applying Cottrell's equation to pulsed electrodeposition enables experimental access to diffusion coefficients (DNi2+). This gives a gradient in DNi2+ along with the filling process. The switch-over from crystallization to diffusion control is investigated to depend on temperature and pore length. Additionally, the electrode surface capacitance scales non-linearly with the pore depth. This is deduced as a consequence of electrostatic surface-electrolyte interaction. A minimum in the electrode capacitance at a pore length of 48 µm is identified as the point with maximum thickness of a double-layer-type surface effect to the electrolyte. The results extend the template's role from simply geometrically limiting metal growth and explain occurring process issues when filling especially high-aspect-ratio pores.

19.
Unfallchirurg ; 117(8): 740-6, 2014 Aug.
Article in German | MEDLINE | ID: mdl-25034278

ABSTRACT

The development of modular prostheses is becoming increasingly important in revision surgery due to the rising need of arthroplasty in knee and hip joints. The demand for suitable prostheses is high because of the desire for a higher mobility and a good postoperative functionality, whereby preliminary experience with megaprostheses using modular implant systems in orthopedic oncology have already been obtained. Considering the clinical outcome of our 58-year-old patient (obesity III, BMI 58) and the third revision operation after two periprosthetic fractures, a megaprosthesis was implanted (Mega C-system, co. Link, Hamburg). We aimed both at good clinical functionality and good stability of the knee joint. After the implant, a good functional result was observed at the beginning; however, there were some indices for prosthesis loosening. During the fourth revision we implanted a total femoral replacement. Postoperatively, a good clinical outcome after intensive physiotherapy was observed. Nevertheless, the use of megaprostheses has to be judged cautiously because of a lack of long-term results. In addition, it should not be used as a standard implant in periprosthetic joint surgery because of the risk of aseptic loosening during its course.


Subject(s)
Arthroplasty, Replacement, Knee/instrumentation , Femoral Fractures/surgery , Fracture Fixation, Internal/instrumentation , Knee Prosthesis , Arthroplasty, Replacement, Knee/methods , Combined Modality Therapy , Equipment Failure Analysis , Female , Femoral Fractures/diagnostic imaging , Fracture Fixation, Internal/methods , Humans , Middle Aged , Prosthesis Design , Prosthesis Failure , Prosthesis Fitting/methods , Radiography , Reoperation/methods , Treatment Failure , Treatment Outcome
20.
Int J Sports Med ; 35(11): 943-8, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24886919

ABSTRACT

Competitive bodybuilding is a weightlifting sport similar to powerlifting, strongman competition and Olympic weightlifting, which aims to increase muscle mass, symmetry, and body definition. Although data regarding rates of injury, overuse syndromes and pain during routine training is available for these other disciplines, it is rare for competitive bodybuilding. The aim of this study was to investigate rates of injury, pain during workouts and/or overuse syndromes, as well as the influence of particular intrinsic and external factors. Data was collected using questionnaires from 71 competitive and elite bodybuilders. The information included training routines and prior injuries. Participants were recruited from bodybuilding clubs in Germany. 45.1% of athletes reported symptoms while training. The overall injury rate was computed to be 0.12 injuries per bodybuilder per year (0.24 injuries per 1 000 h of bodybuilding). Athletes over 40 exhibited higher rates of injury (p=0.029). Other investigated parameters showed no effects. Most injuries occurred in the shoulder, elbow, lumbar spine and knee regions. A large proportion of bodybuilders complained of pain not resulting in interruptions of training/competition. The injury rate is low compared to other weightlifting disciplines such as powerlifting, Olympic weightlifting or strongman competition. In comparison to team or contact sports the injury rate is minimal.


Subject(s)
Cumulative Trauma Disorders/epidemiology , Weight Lifting/injuries , Adolescent , Adult , Competitive Behavior/physiology , Female , Germany/epidemiology , Humans , Lower Extremity/injuries , Male , Middle Aged , Pain/epidemiology , Resistance Training/adverse effects , Retrospective Studies , Spinal Injuries/epidemiology , Upper Extremity/injuries , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...