Swan Neck Research Articles

Jaccoud-type lupus arthropathy.

Jaccoud's arthropathy (JA) is a condition characterized by joint deformities that have a "reducible" pattern, that is, they return to the normal appearance with a passive manoeuvre. JA was described in patients with rheumatic fever (RF) more than a century ago, and presently, the majority of the patients have systemic lupus erythematosus (SLE). The aim of this review is to draw one attention to the epidemiology, pathogenesis, histopathology, clinical features, imaging, and management of JA in patients with SLE (Jaccoud-type lupus arthropathy). The search strategy included articles retrieved from PubMed utilizing the terms "lupus arthropathy", "lupus deforming arthropathy", "lupus hand", "lupus foot", "chronic postrheumatic arthropathy", "Jaccoud's" and "Jaccoud" from 1950 until March 2021, with no language restriction. The prevalence of Jaccoud-type arthropathy in SLE is approximately 5%. The aetiopathogenic mechanisms of JA are not yet known. The most common joint deformities of JA, are ulnar deviation, swan neck, and the "z" of the thumb. Unfortunately, none of the proposed classification criteria for JA have been validated so far. Characteristically, there is no bone erosion on plain radiographs of the joints, but more sensitive imaging methods, magnetic resonance imaging or high-performance ultrasound may reveal small bone erosions. There is no preventive measure against JA development, specific clinical treatment or convincing surgical approach for correcting the deformities. As daily activities and quality of life are compromised in patients with JA, other studies are urgently needed in this area.

Diagnostic Challenges and Management of Patients with Overlapping Rheumatoid Arthritis with Psoriatic Arthritis: A Case Report

Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) have key differences in clinical presentation, radiographic findings, and pathogenesis to distinguish between these common forms of chronic inflammatory arthritis. Several case reports report the occurrence of overlapping syndromes of RA with PsA. However, until now, the cases are still very rare. We report A 33-year-old woman, complaining of pain in the joints of her fingers, toes, and her back since eight years ago. The patient also complained of red, silvery-white patches on the abdomen and spread all over the body. On the left hand, there is a swan neck deformity on the fifth finger of the left hand. On the right hand, there is a boutonniere deformity on the second and fourth fingers of the right hand and ulnar deviation of the first finger. On skin examination, it was found with multiple silvery-white erythematous plaques, varying in size, geographical shape, covered with fine white scales spread all over the body skin. The patient was diagnosed with Rheumatoid Arthritis based on the 2010 ACR/EULAR diagnostic criteria, overlapping with Psoriatic Arthritis syndrome based on the 2010 ASAS diagnostic criteria for spondyloarthropathy 2006 CASPAR for PsA. The right diagnosis process speeds up the time for initiation of appropriate therapy to improve quality of life and improve disease prognosis. Keywords: Rheumatoid arthritis, psoriatic arthritis, overlapping syndrome.

POS-106 CONTINUOUS AMBULATORY PERITONEAL DIALYSIS FOR ACUTE KIDNEY INJURY

Continuous ambulatory peritoneal dialysis is a modality used for Renal replacement in patients with End stage renal disease. Herein we report a patient who developed recurrent cardiac arrest with hemodialysis, and hence CAPD was done to treat her Acute Kidney Injury (AKI). A 55 year old woman presented with complaints of pedal edema, progressive dyspnea from last 1 month, with reduced urine output from last 2 days. Known case of diabetic nephropathy since 1 year, with baseline creatinine of 3.2 mg/dl. History of native medication use for one week. She was suspected to have worsening CKD due to native medicines with a serum creatinine of 10.2 mg/dl, and planned for hemodialysis. She was started on hemodialysis and developed cardiac arrest within half hour of initiation, and further developed seizures within half hour of starting second session, and another episode of cardiac arrest within ten minutes of starting third session despite change of dialyzers and heparin. A possibility of dialyzer reaction was considered and she was planned for continuous ambulatory peritoneal dialysis for her AKI. She underwent bedside insertion of Swan neck Tenckhoff catheter and initiated on CAPD, with 3 exchanges per day and discharged home after 4 days. After two weeks, she developed gradual recovery of renal function and became dialysis independent with creatinine of 4.4 mg/dl. CAPD has rarely been used as a modality for treatment of dialysis for AKI. We report a case of successful use of CAPD for AKI in a patient with repeated cardiac arrests. CAPD can therefore be used with good outcomes in resource limited settings.

Modelling the particle trajectory and melting behaviour of non-spherical ice crystal particles

Existing ice crystal icing codes commonly neglect non-spherical particle rotation behaviour. This leads to uncertainties in modelling ice crystal icing as ice crystals are typically non-spherical. This paper develops a two-dimensional framework to model the particle trajectory and melting behaviour of rotating non-spherical ice crystal particles. Non-spherical particle translational and rotational motions are resolved using a framework of unit complex numbers. The effect of rotation on particle heat and mass transfer is implemented using a sub-model dependent on both rotational and translational particle Reynolds numbers. A test case of flow through a swan neck duct is presented. The model is validated through comparison to the discrete phase model in ANSYS Fluent and experimental water droplet impingement test data. Comparison of the developed framework with other simplified particle tracking methods (without modelling the non-spherical particle rotation) is first conducted. These results show large differences in the trajectory, velocity and melt ratio of individual particles and in overall particle impingement behaviours, especially for high aspect ratio particles. Particle rotation can indirectly affect single particle’s melting behaviour through its effect on particle trajectory and velocity. Both aspect ratio and porosity are seen to enhance particle melting behaviour and affect particle impingement behaviour. The numerical uncertainties in the DNS-based correlations of the particle forces and torques employed are also discussed, as well as the performance of the developed framework for the case of a flow past a test article.

Non-surgical management of displaced bony mallet injuries using dorsal hyperextension splint: an early-term outcome analysis

Purpose: There is still controversy over the ideal treatment of acute bony mallet injuries. The purpose of this study was to evaluate outcomes of a dorsal hyperextension splint treatment for displaced bony mallet injuries. Methods: A retrospective review of a single institution database identified all acute displaced bony mallet injuries that were conservatively treated using dorsal hyperextension aluminum splint in a one-year period. In this method, each splint is custom-made and applied by a one surgeon at the clinic. The demographics, treatment process, complications, and outcomes were reviewed. Results: Seventeen patients (11 men, 6 women) with a mean age of 25.1 years (range 15–45) were enrolled. The mean treatment delay was 7 days (range 1–21). Radiographic healing was achieved in all patients at a mean duration of 5½ weeks (range 4–6 weeks). Early complications included the maceration, prolonged erythema in two patients and a partial thickness wound in one patient. The mean follow-up period was 22 months (range 17–26) for fifteen patients. Late complications included two slight swan neck deformities and one complex regional pain syndrome. Four patients had noticeable (>5°) extension lag between 6° and 11°. Two patients had intractable pain with Visual Analog Scale of 3 and 4 points. Overall, 12 out of 15 fingers were subjectively rated as good or excellent. Conclusion: Using a dorsal hyperextension splint, conservative treatment of displaced bony mallet injury provides overall good results in terms of union rates, patient outcomes, function, and few complications in a short term.

Lattice Model of Multilayer Adsorption of Particles with Orientation Dependent Interactions at Solid Surfaces.

A simple lattice model has been used to study the formation of multilayer films by fluids with orientation-dependent interactions on solid surfaces. The particles, composed of two halves (A and B) were allowed to take on one of six different orientations. The interaction between a pair of differently oriented neighboring particles was assumed to depend on the degrees to which their A and B parts overlap. Here, we have assumed that the AA interaction was strongly attractive, the AB interaction was set to zero, while the BB interaction was varied between 0 and . The ground state properties of the model have been determined for the systems being in contact with non-selective and selective walls over the entire range of BB interaction energies between 0 and . It has been demonstrated that the structure of multilayer films depends on the strengths of surface potential felt by differently oriented particles and the interaction between the B halves of fluid particles. Finite temperature behavior has been studied by Monte Carlo simulation methods. It has been shown that the bulk phase phase diagram is qualitatively independent of the BB interaction energy, and has the swan neck shape, since the high stability of the dense ordered phase suppresses the possibility of the formation of disordered liquid-like phase. Only one class of non-uniform systems with the BB interaction set to zero has been considered. The results have been found to be consistent with the predictions stemming form the ground state considerations. In particular, we have found that a complete wetting occurs at any temperature, down to zero. Furthermore, the sequences of layering transitions, and the structure of multilayer films, have been found to be the same as observed in the ground state.

Non-axisymmetric complete flow conditioning gauzes

This paper presents a novel methodology for the design of a gauze that produces distributions of stagnation pressure, swirl angle, pitch angle and turbulence intensity, tailored in both the radial and circumferential directions. A distortion gauze is made from a large number of small-scale circumferential and radial blades with tailored thickness and camber distributions. By controlling the blade design independently in both the radial and circumferential directions, the target inflow pattern can be achieved. 1D correlations are used to initialise the blades and they are refined using full 3D CFD simulations. The final design is additively manufactured for use in rotating rigs. In this paper, the method has been used to reproduce four target inflow patterns with large variations in stagnation pressure and flow angularity. Two examples model the inlet flow distortion seen at the aerodynamic interface plane of an aft-mounted boundary layer ingesting fan. The final two examples model the inlet distortion at inlet to an axial compressor spool caused by upstream structural struts in a swan neck duct. The gauzes are shown to replicate the structures of the target flow in an experimental test. These kind of flow structures would be extremely difficult or impossible to replicate in an experiment in any other way.Graphical abstract

Effect of a Flexor Digitorum Superficialis Hemitenodesis on Reducing Volar Plate Strains for Swan Neck Deformities.

Flexor digitorum superficialis (FDS) hemitenodesis is a common procedure to treat swan neck deformity (SND). We hypothesize that this surgical technique is a biomechanically effective way to reduce strain in the volar plate at the proximal interphalangeal joint (PIPJ). Fifteen digits from 5 cadaveric specimens were tested using a novel in vitro active finger motion simulator under 4 finger conditions: intact, SND, FDS hemitenodesis, and FDS hemitenodesis with distal interphalangeal (DIP) joint fusion. Tensile loads in FDS and flexor digitorum profundus (FDP) and joint ranges of motion were measured by electromagnetic tracking. In addition, strain gauges were inserted under the volar plate to measure strain during PIPJ hyperextension. Results were analyzed using 1-way repeated-measures analysis of variance tests. The SND condition increased volar plate strain by 176% ± 25% (P < .001) compared with the intact condition. The FDS hemitenodesis repair relieved more than 50% of the SND strain, restoring it to within no statistical difference from intact. The DIP fusion further reduced strain with no further statistical significance. At full flexion, FDS and FDP tendon loads diverged as a function of the test condition (P < .001). With the FDS hemitenodesis, the FDP load increased by 2.1 ± 1.5 N from the SND condition (P < .001), whereas the FDS load decreased by 1.3 ± 1.3 N (P = .012). The FDS hemitenodesis repair restored strains to within 3.0 milli-strain of the intact condition with no significant difference. Application of DIP fusion did not further protect the PIPJ from increased hyperextension and further exacerbated the imbalance of flexor tendon loads.

Super Aggressive S-Ducts for Air Breathing Rocket Engines

Abstract Air breathing rocket engines require turbomachinery and ducting that is substantially lighter than that used in ground-based or aerospace gas turbines. In order to reduce the weight of the axial compressor, the design of the inter-spool swan neck duct is targeted. In this paper, a circumferential splitter blade is used to reduce loading and diffusion on the duct endwalls. The splitter and duct geometry are coupled and optimized together using 2D CFD. A design is selected that is 30% shorter than ducts that are currently used in aerospace gas turbines, and the 3D flow features are investigated in further detail using an experimental rig and 3D CFD. This paper shows that the “splittered” duct has three benefits over a conventional duct design: first, separation of the endwalls is prevented even at short duct lengths, this will reduce distortion into the downstream compressor. Second, losses generated by corner separations on structural struts can be reduced by 20%, enabling short ducts to achieve high performance. Third, splittered ducts are shown to be twice as robust to uncertain inlet flow conditions as conventional ducts. This allows a designer to target high-performance short designs with reduced risk.

Percutaneous management of swan neck deformity using WALANT: case report featuring a new surgical technique

Percutaneous staged lateral band tenotomy can restore the balance between finger flexion and extension in the management of swan neck deformity due to intrinsic muscle retraction. Using WALANT confirmed the effectiveness of this technique because it provides an instantaneous intraoperative assessment of the deformity's correction.

Spiral Oblique Retinacular Ligament Procedure Using Flexor Digitorum Profundus Hemi-Tendon Transfer: Anatomical Basis and Clinical Application

The spiral oblique retinacular ligament (SORL) procedure acts as a dynamic tenodesis to restore distal interphalangeal joint (DIP) extension and restrain proximal interphalangeal hyperextension. Despite the ingenious technique based on the oblique retinacular ligament anatomy, obtaining strong internal fixation remains an issue during the SORL procedure. We present a modified technique using the flexor digitorum profundus (FDP) hemi-tendon transfer. We dissected 5 fresh cadaveric specimens to evaluate morphometric parameters of the SORL procedure using the hemi-FDP. The volar groove of the FDP tendon was identified in zone I of the flexor sheath and the tendon was divided into radial and ulnar bundles. The selected hemi-tendon was divided at the proximal edge of the A1 pulley and a SORL procedure was performed through a transosseous tunnel in the distal phalanx. This technique was used in 3 patients with swan neck deformity. The optimal distance between the DIP joint and the anterior drill hole of the transosseous tunnel was 7.6 mm (range, 6.8-8.5 mm). The relative loss of length of the tendon owing to the SORL path was 25.8 mm (range, 19.6-29.9 mm). In the clinical cases, the procedure improved DIP joint extension lag and prevented proximal interphalangeal joint hyperextension. Preserving one-half of the FDP allowed complete flexion of the DIP joint. The procedure is technically feasible. Its main advantages are that a distal suture is not required and that the substantial length of the tendon allows sturdy proximal internal fixation. Therapeutic V.

A single K-wire to prevent poor outcomes in closed soft-tissue mallet finger management due to patient non-compliance.

Soft-tissue mallet finger occurs due to loss of terminal extensor tendon secondary to rupture of distal phalanx. Although using noninvasive splints for 6-8weeks is the gold standard for conservative treatment of closed soft-tissue mallet injuries, patient compliance is an important factor impacting on patient outcomes. In this study, we used a single Kirschner Wire (K-W) to fix the distal interphalangeal (DIP) joint in extension in those patients failed to comply with routine splinting. In this prospective study, 190 patients with Doyle type 1 closed soft-tissue mallet finger deformity were included in four groups between 2011 and 2015. These groups were determined according to treatment modalities. Patients in the first group were treated with a finger splint (n = 109). Patients in the second group first received a finger splint and then K-W was applied due to lack of adequate compliance (n = 23). Patients in the third group were treated with K-W only (n = 47), and the fourth group did not accept surgical treatment nor conservative treatment (n = 11). After 20weeks of follow up, we evaluated the results with functional measurements according to Crawford criteria and patient satisfaction. Additionally, the mid-term outcome was assessed with a follow-up at 2years. At 20th week postoperatively, average DIP extension lag was 6 degrees (0-30) for the first group, 6.1 degrees (0-30) for the second group, 3.8 degrees (0-25) for the third group, and 17.3 degrees (7-30) for the fourth group. Total patient satisfaction was 85%, which was considered excellent or good. Swan neck deformity was observed in 11% of patients. Osteomyelitis and KW related complications were not observed. There were no statistically significant differences between short-term and mid-term results. Internal fixation via K-W may be a suitable treatment option compared to splint therapy for management of closed soft-tissue mallet finger in noncompliant patients. Using this treatment approach, the success rate for patients could satisfactorily be improved.

A Sudanese Male with Jaccoud’s Arthropathy; Case Report

JA is a non-erosive deforming form of arthropathy that is characterized by correctable joint deformities such as ulnar deviation, thumb subluxation and swan neck deformity...

Some Drew Horses, and: Dash, and: The Family

Some Drew Horses, and: Dash, and: The Family Angela Sorby (bio) Some Drew Horses The two Kellys whocould draw horsesin third gradeunderstood balance.Their horses canteredacross construction paper.The Kellys loosedtheir small motorskills, and musclesrippled through their pencils.Their ponytails,shining in scrunchies,said Look At Me.No saddle, no rider.When we were older I'd envythe Kellys their beauty,and later still search Facebookto confirm they got fatin their forties,but when they were horsesI was their sky, their poppies,their prairie. On and onthey ran through me,with such authorityit was hard to believe—no, I still don't believe—we were children. [End Page 95] Dash My worst college job was typing triplicate insurance claims so badly I kept starting over, feeding sheets into an Underwood typewriter as neurotoxins rose from the Liquid Paper jar, obliterating most of the late eighties, plus I drank after work, so don't blame me, PJ, if I've forgotten how to fall in love—where to go, what to eat, who pays. After years of teaching I talk like I know what I'm saying, but, per npr's Shankar Vedantam, vertebrates—fish, birds, people—act with our primeval brainstems first. Only later do we dredge up words like love, whatever that means. Last night a raptor landed on my shoulder in a dream. Way way back in the twentieth century, Freudians would mansplain: you're ambivalent, you're afraid, but gone are the days of the wellangela [End Page 96] padded psychoanalytic interior. What's left? The spine holds what the mind drops: nodes, not sentences. Go above your nerve, wrote Dickinson, Queen of the Overthinkers, but when she fell for Judge Otis Lord, it hit her— the dash, the ecstatic erasure. The Family Before our divorce my exdealt books, so one yearour basement was suddenlyfull of a dead mob boss's library—torture manuals,philosophy, criminal law,opera librettos, and of course,Mario Puzo's The Godfather. Some volumes were heavilyannotated: How to Dominate Others,Stalin's Strategies. The boss,one Joey Balistrieri, spent his jail terms literallystudying how to be evil,marking key passages.If there's an evil gre, he passed— bribing cops, whacking rivals,but when I picture Joey in his cell,bent over Machiavelli's The Prince,his neck is smooth and vulnerable, [End Page 97] a swan's neck, as if evil misseda few nodes in back and relaxedinto—if not innocence,then curiosity. Now he's nowhere mail goes,but if I could send him a gentlebook (Charlotte's Web, maybe?)I'd inscribe the flyleaf Dear Uncle Joey,since whatever dnamakes us readersmakes us forever family. [End Page 98] Angela Sorby Angela Sorby is Professor of English and Director of the Graduate Program at Marquette University in Milwaukee. She's the author of three poetry books, Distance Learning (New Issues 1998), Bird Skin Coat (U of Wisconsin P 2009), and The Sleeve Waves (U of Wisconsin P 2014), plus a critical book, an anthology of children's poetry, and an edited collection on poetry and pedagogy. Her poetry has won a Midwest Book Award, the Brittingham Prize, the Felix Pollak Prize, the Lorine Niedecker Prize, Discovery/The Nation, and other honors. Copyright © 2021 University of Nebraska Press

PATIENT-REPORTED OUTCOMES FOR USE OF SILVERSPLINTS IN OSTEOARTHRITIS OF THE HAND.

Pain, stiffness and joint deformity can result in significantly reduced hand function in people with osteoarthritis. Characteristic finger deformities in osteoarthritis are swan neck deformity and boutonnière deformity. Several studies have reported that an orthosis decreases pain and increases function during daily activities for patients with arthritis. The aim of this study was to review patient-reported outcomes of current conservative therapeutic management with silver ring splints (silversplints) for patients with osteoarthritis of the hand. There was a 76% improvement in overall daily functioning and a 74% reduction in pain. Several questions concerned daily activities with different types of hand function and with different types of grip and use of fingers. The results show a major improvement in both the more open grip of the hand and activities requiring fine motor skills. The ability to use force with the hand, even when wearing an orthosis, is an important result. Patients who experienced “no problems or minor problems” had significantly increased functioning in several activities of daily living, but the largest improvement in functioning was seen in “household chores” (243%), “opening jars” (150%) and “lifting groceries” (143%). Overall, silversplints appear to serve as a suitable support for the joints in osteoarthritis of the hand, providing pain relief by preventing the joint from moving through its full range of motion. Use of silversplints to treat patients with osteoarthritis of the hand should be considered as a useful, non-surgical method.LAY ABSTRACTThis study of patient-reported outcome measures regarding the use of silversplints for osteoarthritis of the hand provides insight into the additional care and quality of life provided by the use of an orthopaedic medical aid. The aims of this study are to measure the effectiveness of silversplints in daily life and to validate the efficacy of using orthopaedic medical aids. Between October 2018 and June 2020, a total of 2,231 patients with osteoarthritis were provided with silversplints and were asked about the effectiveness of the splints 3 weeks after they first started wearing them. This large-scale study found that the use of silversplints contributed to overall daily functioning, reduced pain, and increased the possibility of performing daily activities. Silversplints appear to serve as a suitable support for joints, providing pain relief and freedom of movement, but preventing the joint from moving through its full range of motion.

An overview of mallet finger injuries.

Mallet finger describes a fingertip deformity where the distal interphalangeal joint (DIPJ) of the affected digit is held in flexion, unable to extend the distal phalanx actively. The deformity is typically a consequence of traumatic disruption to the terminal extensor tendon at its insertion at the proximal portion of the distal phalanx or slightly proximally at the level of the DIPJ. Patients typically present with a history describing the event of injury with a typical mallet deformity. Common mechanisms include sport activities causing a direct blow to the finger, low energy trauma while performing simple tasks such as pulling up socks or crush injuries from getting the finger trapped in a door. The DIPJ can be passively extended, but this extension of the joint cannot be maintained once the passive extension is stopped. The Doyle classification can be used to categorise and dictate treatment. The extensor lag associated with the deformity does not improve spontaneously without treatment. Inappropriate management can lead to chronic functional loss and stiffness of the finger. The majority of closed mallet splints are Doyle type I, which can be managed non-surgically with external splints, worn full-time to keep the fingertip straight until the tendon injury or fracture heals. Surgical techniques is considered for other types of mallet injuries. Techniques used include closed reduction and Kirschner wire fixation, open reduction and internal fixation, reconstruction of the terminal extensor tendon and correction of swan neck deformity. (www.actabiomedica.it)

The Dynamic Thumb-in-Palm Pattern in Children with Spastic Cerebral Palsy and Its Effects on Upper Limb Function.

The thumb-in-palm (TIP) pattern is one of the most common upper limb deformities in cerebral palsy (CP). This study was designed to investigate the effect of the dynamic TIP pattern on upper limb function in children with spastic CP. This prospective observational study included a total of 106 children with CP with dynamic TIP. The House TIP classification while grasping small or large objects, Melbourne Assessment of Unilateral Upper Limb Function (MUUL), Shriners Hospital Upper Extremity Evaluation (SHUEE), Zancolli classification for wrist–finger flexor deformity, and degree of swan neck deformity were assessed. Type I was the most common and highest functioning House TIP classification type. However, there were no significant differences in upper arm function between types II, III, and IV. The three components of the SHUEE showed stronger association with MUUL than House TIP and Zancolli classifications. After multivariable analysis, functional use of the wrist–finger and the thumb played a more significant role than the dynamic alignment of the thumb. In conclusion, the House TIP classification is useful to describe the TIP pattern. The SHUEE thumb assessment is a useful tool for reflecting upper arm function. The upper arm function was related more with the associated wrist flexor deformity than dynamic TIP.

Development of an In Vitro Swan Neck Deformity Biomechanical Model.

Injury to the finger's extensor mechanism is a common cause of swan neck deformity (SND). Progression of extensor and flexor tendon imbalance negatively affects laxity of the volar plate, resulting in the inhibition of proper finger motion. The complexity of finger anatomy, however, makes understanding the pathomechanics of these deformities challenging. Therefore, development of an SND model is imperative to understand its influence on finger biomechanics and to provide an in vitro model to evaluate the various treatment options. The index, middle, and ring fingers from 8 cadaveric specimens were used in an in vitro active motion simulator to replicate finger flexion/extension. An SND model was developed through sectioning of the terminal extensor tendon at the distal insertion (creating a mallet finger) and transverse retinacular ligament (TRL). A strain gauge inserted under the volar plate measured laxity of the plate, and electromagnetic trackers recorded proximal interphalangeal joint (PIPJ) angles. Strain in the volar plate increased progressively with creation of the mallet and SND conditions (P = .015). Although not statistically significant, the mallet finger condition accounted for 26% of the increase, whereas sectioning of the TRL accounted for 74% (P = .031). As predicted, PIPJ hyperextension was not detectable by joint angle measurement; however, the PIPJ angle had a strong positive correlation with volar plate strain (R2 = 1.0, P < .001). Volar plate strain measurement, in an in vitro model, can detect an induced SND. Moreover, as a surrogate for PIPJ hyperextension, volar plate strain may be useful to evaluate the time-zero effectiveness of various surgical interventions.

Compact W-Band “Swan Neck” Turnstile Junction Orthomode Transducer Implemented by 3-D Printing

A turnstile junction orthomode transducer (OMT) provides polarization separation/combining on a full waveguide bandwidth; however, it bears a complex connecting structure, which accordingly leads to a bulky volume. We present a compact W-band (75-110 GHz) OMT using a “swan neck” twist for the connection between a turnstile junction and an E-plane Y-junction, for minimizing the overall OMT structure. The core volume for the proposed OMT is 9× less than the previously reported stacked-layer OMT. The compact W-band OMT was built by digital light processing (DLP) 3-D printing technology and was postmetallized by silver electroless plating. The return loss of the vertical-polarized port (V-port) and the horizontal-polarized port (H-port) is characterized, as averagely 17 and 15 dB, respectively. The measured average insertion loss from H- and V-ports to the common port is 0.5 and 0.6 dB. The measured isolation between V- and H-ports is averagely 28 dB. Furthermore, the turnstile junction asymmetry along the central axis was revealed in computed tomography (CT) scanned images. The simulation shows a negative effect of the asymmetric structure on the OMT isolation. In addition, the dual-polarized (dual-pol) antenna combining such OMT and a corrugated horn was realized in a compact size. The cross-polarization level of the OMT, characterized in a far-field test of this dual-pol antenna, is averagely -18 dB at the W-band.

Evaluation of non-infectious complications of peritoneal dialysis in children: a multicenter study.

Peritoneal dialysis (PD) is the most common kidney replacement therapy in children. Complications associated with PD affect treatment success and sustainability. The aim of this study was to investigate the frequency of PD-related non-infectious complications and the predisposing factors. Retrospective data from 11 centers in Turkey between 1998 and 2018 was collected. Non-infectious complications of peritoneal dialysis (NICPD), except metabolic ones, in pediatric patients with regular follow-up of at least 3months were evaluated. A total of 275 patients were included. The median age at onset of PD and median duration of PD were 9.1 (IQR, 2.5-13.2) and 7.6 (IQR, 2.8-11.9) years, respectively. A total of 159 (57.8%) patients encountered 302 NICPD within the observation period of 862 patient-years. The most common NIPCD was catheter dysfunction (n = 71, 23.5%). At least one catheter revision was performed in 77 patients (28.0%). Longer PD duration and presence of swan neck tunnel were associated with the development of NICPD (OR 1.191; 95% CI 1.079-1.315, p = 0.001 and OR 1.580; 95% CI 0.660-0.883, p = 0.048, respectively). Peritoneal dialysis was discontinued in 145 patients; 46 of whom (16.7%) switched to hemodialysis. The frequency of patients who were transferred to hemodialysis due to NICPD was 15.2%. Peritoneal dialysis-related non-infectious complications may lead to discontinuation of therapy. Presence of swan neck tunnel and long duration of PD increased the rate of NICPD. Careful monitoring of patients is necessary to ensure that PD treatment can be maintained safely.