Electrochemical Reaction in Single Layer MoS2: Nanopores Opened Atom by Atom.

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.

[Indication and Results of the Anderson Procedure]. / Indikation und Ergebnisse der Anderson-Operation.

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.

Surface Influences on the Electrodiffusive Behavior in Mesoporous Templates.

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.

[German translation and validation of the Stress Appraisal Measure (SAM)]. / Deutsche Übersetzung und Validierung des Stress Appraisal Measure (SAM).

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.

Fermi-surface reconstruction and complex phase equilibria in CaFe2As2.

Fermi-surface topology governs the relationship between magnetism and superconductivity in iron-based materials. Using low-temperature transport, angle-resolved photoemission, and x-ray diffraction, we show unambiguous evidence of large Fermi-surface reconstruction in CaFe2As2 at magnetic spin-density-wave and nonmagnetic collapsed-tetragonal (cT) transitions. For the cT transition, the change in the Fermi-surface topology has a different character with no contribution from the hole part of the Fermi surface. In addition, the results suggest that the pressure effect in CaFe2As2 is mainly leading to a rigid-band-like change of the valence electronic structure. We discuss these results and their implications for magnetism and superconductivity in this material.

Injuries and overuse syndromes in competitive and elite bodybuilding.

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.

[Special prosthesis implant with partial femoral replacement. Operation after periprosthetic femoral fracture and ipsilateral long-stem knee prosthesis and fixed-angle osteosynthesis]. / Implantation eines Femurteilersatzes nach periprothetischer Femurfraktur. Operation bei einliegender Knietotalendoprothese und winkelstabiler Plattenosteosynthese.

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.

[ChatGPT and the German board examination for ophthalmology: an evaluation]. / ChatGPT und die deutsche Facharztprüfung für Augenheilkunde: eine Evaluierung.

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.

How to deal with diplopia.

Diplopia is a frequent neuro-ophthalmologic symptom with diverse etiologies. This article describes elementary diagnostic tests and frequent causes of diplopia. Monocular diplopia persists when the other eye is closed and usually disappears when the patient looks through a pinhole. It is usually caused by errors in the optical media of the eye and has to be differentiated from spectacle-induced side effect and non-organic disorders. A sign of non-organic etiology is absence of change in image position when the head is tilted. Binocular diplopia disappears regardless of which eye is closed. Binocular diplopia occurs when the images of both eyes cannot be fused. The most frequent direct cause of diplopia is acquired strabismus. Knowledge of several specific types of strabismus enables efficient patient management. Congenital and decompensating strabismus like accommodative esotropia, pathophoria, strabismus surso- and deorsoadductorius, retraction syndrome, Brown's syndrome and esotropia in high myopia only need ophthalmologic treatment. Orbital injury, orbital tumor, ocular myositis, Graves orbitopathy and vascular disease usually require multidisciplinary management. Neurogenic paresis, superior oblique myokymia, ocular neuromyotonia, myasthenia, chronic progressive external ophthalmoplegia (CPEO), internuclear ophthalmoplegia (INO) and skew deviation require specific neurologic examination. Treatment of diplopia includes treatment of the fundamental disorder, monocular occlusion, prisms and strabismus surgery.

[Bilateral medial rectus recession with posterior fixation suture for large infantile esotropia]. / Beidseitige Medialis-Rücklagerung mit Fadenoperation bei großer frühkindlicher Esotropie.

BACKGROUND: Surgery for infantile large angle esotropia is not uniform. Bilateral medial rectus recession (BMR), combined recess-resect procedure, also combined with simultaneous contralateral medial rectus recession or secondary other procedures are common. Alternatively, bilateral medial rectus recession with posterior fixation suture (BMRF) has been used. We analysed the effect of BMRF for this specific indication. PATIENTS AND METHODS: We undertook a retrospective evaluation of squint angles in simultaneous (S) and alternating (A) prism cover test before and 3 months after BMRF with and without additional oblique muscle surgery as primary surgery for esotropia ≥ 20° performed at our department between 1997 and 2009, as well as the rate of second procedures. RESULTS: Sixty-one children (0.5 % of all patients who received eye muscle surgery during the same time interval) were included. Medians (10 % and 90 % quantiles) were: age at surgery 48.4 months (23.6; 76.0), refraction (spherical equivalent)2.25 dpt (0.25; 5.50), posterior fixation 5.5 mm + 13.0 mm (12.5; 13.0) from limbus, recession 5.0 mm (4.0; 5.0), inferior oblique recession in 29 children (27 bilateral), preoperative squint angles at 5 m S/A 29° (20; 40), at 0.3 m S/A 35° (24; 45), postoperative at 5 m S 0° (-6; 10), A 2° (-6; 11), at 0.3 m S 1° (-5; 12), A 3.5° (-5; 13), S ≤ 5° in 70.2 % at 5 m and 60.3 % at 0.3 m, consecutive exotropia 6-10° and > 10° in 7.0 and 3.5 % at 5 m and 8.6 and 1.7 % at 0.3 m, residual esotropia 6-10° and > 10° in 10.5 and 8.8 % at 5 m and 13.8 and 15.5 % at 0.3 m. Seven children (11.5 %) were re-operated for esotropia, four for exotropia (6.6 %). CONCLUSION: Bilateral medial rectus recession with retroequatorial myopexy (Cüppers procedure) is an effective one-step procedure for large infantile esotropia. In roughly two-thirds of the cases, the squint angle was corrected within ±â€Š5° with one surgery, which is similar to reported success rates of BMR.

Stability of self-reported psychopathic traits in at-risk adolescents in youth welfare and juvenile justice institutions.

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.

Healthcare-associated infections: a threat to the survival of patients with COVID-19 in intensive care units.

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.

Unconventional superconductivity in PuCoGa5.

In the Bardeen-Cooper-Schrieffer theory of superconductivity, electrons form (Cooper) pairs through an interaction mediated by vibrations in the underlying crystal structure. Like lattice vibrations, antiferromagnetic fluctuations can also produce an attractive interaction creating Cooper pairs, though with spin and angular momentum properties different from those of conventional superconductors. Such interactions have been implicated for two disparate classes of materials--the copper oxides and a set of Ce- and U-based compounds. But because their transition temperatures differ by nearly two orders of magnitude, this raises the question of whether a common pairing mechanism applies. PuCoGa5 has a transition temperature intermediate between those classes and therefore may bridge these extremes. Here we report measurements of the nuclear spin-lattice relaxation rate and Knight shift in PuCoGa5, which demonstrate that it is an unconventional superconductor with properties as expected for antiferromagnetically mediated superconductivity. Scaling of the relaxation rates among all of these materials (a feature not exhibited by their Knight shifts) establishes antiferromagnetic fluctuations as a likely mechanism for their unconventional superconductivity and suggests that related classes of exotic superconductors may yet be discovered.

Electronic duality in strongly correlated matter.

Superconductivity develops from an attractive interaction between itinerant electrons that creates electron pairs, which condense into a macroscopic quantum state-the superconducting state. On the other hand, magnetic order in a metal arises from electrons localized close to the ionic core and whose interaction is mediated by itinerant electrons. The dichotomy between local moment magnetic order and superconductivity raises the question of whether these two states can coexist and involve the same electrons. Here, we show that the single 4f electron of cerium in CeRhIn(5) simultaneously produces magnetism, characteristic of localization, and superconductivity that requires itinerancy. The dual nature of the 4f-electron allows microscopic coexistence of antiferromagnetic order and superconductivity whose competition is tuned by small changes in pressure and magnetic field. Electronic duality contrasts with conventional interpretations of coexisting spin-density magnetism and superconductivity and offers a new avenue for understanding complex states in classes of materials.

[Comparison of visual acuity measured using Landolt-C and ETDRS charts in healthy subjects and patients with various eye diseases]. / Vergleich von Landoltring- und ETDRS-Buchstaben-Sehschärfe bei Augengesunden und Patienten mit unterschiedlichen Augenerkrankungen.

PURPOSE: Results of visual acuity determination can differ depending on the stimuli being used, even if their critical details appear under the same visual angle. In this study, visual acuity measured with the Landolt C was compared to acuity measured with ETDRS charts in subjects with and without visual disorders. PATIENTS AND METHODS: One hundred patients (age 8 to 90 years) with strabismus amblyopia (39), refractive amblyopia (5), cataract (24) and maculopathy (32) as well as 13 healthy volunteers (age 18 to 33 years) were examined. Retro-illuminated ETDRS 1, 2 and R charts (Lighthouse) and a retro-illuminated Landolt C chart with the same arrangement of optotypes (Precision Vision) were used. Three out of 5 optotypes in each line had to be correctly identified. In the patient group, the eyes with the lower visual acuity were tested, while the right eyes of the healthy subjects were monitored. Wrong answers were monitored and the results were noted in interpolated logMAR. RESULTS: Differences between Landolt C (LC) and ETDRS acuity were only small and statistically not significant. LogMAR values (SEM in parentheses) for LC /ETDRS 1 were: entire group: 0.60 (0.04)/ 0.55 (0.04), strabismus amblyopia: 0.85 (0.08)/ 0.80 (0.08), refractive amblyopia: 0.27 (0.04)/ 0.23 (0.05), cataract: 0.57 (0.07)/ 0.51 (0.07), retinal disease: 0.67 (0.06)/ 0.61 (0.06), healthy eyes: -0.17 (0.03)/ -0.17 (0.02). The mean difference between LC and ETDRS 1 was 0.49 lines in the entire group and 0.51 lines in strabismus amblyopia in favour of ETDRS 1 values. ETDRS 2 and R charts yielded similar results. CONCLUSIONS: In healthy subjects and in patients with various eye disorders including strabismus amblyopia, there was only a slight difference between visual acuity measured by ETDRS charts compared to the Landolt C. Comparing data of different settings it must be considered that in the lower visual acuity range (< 0.32), the mean ETDRS acuity of adults overestimates the Landolt C acuity by 0.5 and 1.0 line.

[Surgery for strabismus sursoadductorius (congenital superior oblique palsy) in childhood]. / Behandlung des Strabismus sursoadductorius (congenital superior oblique palsy) im Kindesalter.

PURPOSE: The aim of this study was to evaluate the effect of inferior oblique muscle recession (IOR) in children with pure unilateral strabismus sursoadductorius (so-called congenital superior oblique palsy, CSOP) operated before age 11 years. PATIENTS AND METHODS: A retrospective study of IOR in children with unilateral CSOP and surgery before age 11 years was undertaken. In most cases, recession and anteroposition of the anterior part of the inferior oblique tendon next to the lateral edge of the inferior rectus muscle was performed without fixation of the posterior part of the tendon. Main outcome measures were change in abnormal head tilt, change in vertical deviation, both in straight and contralateral side gaze, and evaluation of squint angles. RESULTS: Between 1997 and 2007, 36 consecutive children (aged 2 -10 years; 27 boys, 9 girls) received IOR for unilateral CSOP. The dose of IOR ranged between 6 and 12 mm. Vertical deviation in straight and contralateral gaze was reduced from median 5° (range 0 - 11°) and 12° (3 - 20°) to 0° (-2 - 8°) and 1° (-5 - 13°), respectively. Abnormal head tilt towards the contralateral shoulder was reduced from median 10° (0 - 20°) to 0° (-2,5 - 10°). Three children (8 %) received further extraocular muscle surgery within 2 years, one because of persistent hyperdeviation, and two because of consecutive hypodeviation of the operated eye. CONCLUSIONS: The results indicate that IOR with fixation of only the anterior part of the inferior oblique to the sclera is an effective treatment for strabismus sursoadductorius/CSOP in children. Undercorrection into a residual, well compensated stage is a satisfying result. Both overcorrection and elevation deficiency were rare.

Frustrated Heisenberg J1-J2 model within the stretched diamond lattice of LiYbO2.

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.

Regulation of antibody formation by serum antibody. I. Removal of specific antibody by means of immunoadsorption.

Rabbits were injected intravenously with bovine serum albumin (BSA) and bacteriophage T(2) (T(2)). 2-3 wk later, anti-BSA was removed from such animals by a procedure which involved exposure of removed plasma to an immunoadsorbent ((125)I-BSA bound to bromoacetyl cellulose) and return of the adsorbed plasma to the animal. This resulted in removal of the majority of antibody activity to BSA without affecting antibody levels to T(2). 1-2 days later, anti-BSA levels began to rise, and reached peak levels usually 5 days after the removal of antibody. Antibody levels to T(2) did not change. No evidence was obtained that BSA was released from the immunoadsorbent into the circulation of the rabbits. Thus, only trace amounts of radioactivity were released into the plasma; most of the radioactivity was equally coprecipitable with BSA or human gamma globulin and their specific antibodies; the released material was not demonstrated to be immunogenic in primed rabbits; and the released material did not elute with BSA on gel filtration. The results are interpreted as evidence that serum antibody acts as a regulatory mechanism for antibody formation during the conventional antibody response to a metabolizable antigen.

Regulation of antibody formation by serum antibody. II. Removal of specific antibody by means of exchange transfusion.

Rabbits were immunized to two antigens and 18-55 days later exchange transfusion was performed using blood of rabbits immunized to one antigen only. By this means, serum antibody levels to one antigen were reduced 50-84% while maintaining serum antibody levels to the second antigen. After exchange, serum antibody levels of the removed antibody rose rapidly for 24-48 hr and then more slowly, reaching peak titers an average of 8 days later. The peak titer was 48-222% higher than the preexchange titer. The specificity of this rebound excluded as a cause nonspecific changes in Ig levels. Passive administration of antibody to a third antigen 4-7 days before the exchange indicated that re-equilibration of preformed antibody was not a major factor in the rebound. A change in the ratio of IgM to IgG antibodies as a cause of an increased neutralization titer in the postexchange sera was also excluded. It was therefore suggested that a change in the rate of antibody formation had occurred, although other changes in the quality of serum antibody were not excluded.

[Operative treatment of pediatric open fractures of the lower limb using the Taylor spatial frame fixator]. / Versorgung der kindlichen offenen Unterschenkelfraktur mit dem Taylor-spatial-frame-Fixateur.

The operative management of open fractures of the lower limb requires a consistent treatment to avoid soft tissue complications. Acute angular shortening of the fracture enabling primary soft tissue closure is still an uncommon operative technique because of difficulties in correcting the secondary deformity. The case of a pediatric open fracture of the lower limb (Gustilo type IIIa) is described, which was treated with acute angular shortening followed by gradual correction using the Taylor spatial frame (TSF).