bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and construction of ferrite waveguide circulator with short wall in S band
Authors: Oskouei Hamid Reza Dalili , Khoshcheshm Morteza , Shirkolaei Morteza Mohammadi , Mirtaheri Ali Reza 
Published: August 2023

AbstractOne of the most important components in the radar and microwave industry that provides transmitting and receiving features for an antenna at the same time is called a circulator. Ferrite circulators are passive three‐port devices in which the RF or microwave signal is transmitted from one port to other port without leakage to the third port. One of the main disadvantages of these waveguide elements is their large dimensions and especially their height, which cannot be used in some systems due to the limited workspace. This paper solves this problem by exploiting an incomplete wall waveguide to reduce the height of the circulator by 50%. These changes always reduce the frequency bandwidth of the element, the proposed technique optimizes the dimensions of the ferrite and its magnetic characteristics and increases the bandwidth to 400 MHz in 2.9 GHz, which is the ideal bandwidth required by many radar systems that have been reached. The ferrite circulator designed and built in this article has a port with a width of 72.13 mm and a height of 17 mm in the S‐band. The method results in a low insertion loss which is less than 0.5 decibels and a high isolation which created more than 20 decibels. The designed and optimized elements have been implemented and the test results verify the theoretical results.
Antegrade versus Retrograde Cardioplegia for Uncomplicated Coronary Artery Disease: A Comparative Study
Authors: Hunt Allen , Stammers Alfred , Robinson Lary A. 
Published: August 2023

Since the introduction of the retrograde administration of cardioplegic solutions in cardiac surgery in the mid-1980's, the technique has been widely adopted for routine use in high risk patients with impaired ventricular function, based on favorable results demonstrated in clinical series. However, we sought to evaluate the benefits of routine use of this method in low risk patients by means of a retrospective review of 34 consecutive non-repeat, isolated coronary artery bypass grafting patients with left ventricular ejection fractions > 35%. Seventeen patients received intermittent ante grade cardioplegia exclusively and 17 received ante grade induction followed by intermittent retrograde cardioplegia maintenance. No significant baseline differences were found between the two groups. There were no deaths or major complications in either group. Retrograde cardioplegia patients had significantly lower pulmonary artery diastolic pressures in the first 24 hours postoperatively, accompanied by a non-significant trend toward higher cardiac indices during this same period. Phenylephrine infusions were used more frequently during the postoperative period in the retrograde group (p = 0.021). Fewer pulmonary complications were seen in the retrograde cardioplegia group (p=0.042), in addition to non-significant trends toward less atrial arrhythmias and less hospital days. No adverse effects or increased operative time could be attributed to the retrograde administration of cardioplegic solution in this study population.
Based on the results from this small clinical series, retrograde cardioplegia administration offers distinct advantages for myocardial protection in low risk coronary bypass patients, as manifested by improved postoperative hemodynamic performance, with no significant adverse effects. A prospective, randomized trial of this technique in a larger, similar patient population is likely to show even more compelling positive results favoring the routine use of retrograde administration of cardioplegic solutions.
Evaluation of Blood Loss and Transfusion Requirements in Diabetic and Non-Diabetic Patients Undergoing Coronary Revascularization
Authors: Maca Patricia E. , Stammers Alfred H. , Galbraith Timothy , Alonso Anselmo 
Published: August 2023

Hematological abnormalities associated with the diabetic state include reduced platelet function, enhanced factor activation and hyperfibrinolysis. The present investigation evaluated blood loss and the transfusion requirements in diabetic and non-diabetic patients undergoing extracorporeal circulation and cardiac surgery.
A retrospective study of 151 consecutive patients undergoing primary coronary revascularization were classified into one of three groups based on their diabetic disease state: Insulin Dependent Diabetics (IDDM, n=5), Non-Insulin Dependent Diabetics (NIDDM, n=33), and Non-Diabetics (NDM, n=113). IDDM patients were significantly younger than either NIDDM or NDM patients, were 80% female, and had lower preoperative red cell mass. The IDDM group had a greater red blood cell transfusion volume (1650 ± 1485 ml) than NIDDM (958 ± 593 ml) and NDM (997 ± 827 ml) patients (p=0.21). There were no significant differences in homologous blood exposure or chest tube drainage in any group. Mean length of hospital stay (days) in the IDDM group (19.8 ± 18.3) was significantly greater than the NIDDM (9.9 ± 3.7), and the NDM (10.8 ± 5.8) patients (p<.001).
In conclusion, diabetic patients do not appear to be at increased risk for developing postcardiotomy coagulopathies, despite having greater morbidity, which results in increased hospital stay.
Extracorporeal Circulation for Great Vessels Surgery: A Review of 131 Cases
Authors: Dong Peiqing , Sun Yanqing , Yang Jing , Yang Chuanrui , He Meiling 
Published: August 2023

A retrospective analysis of 131 cases of major vascular surgery, mainly aneurysms of the ascending and descending aorta, was undertaken to determine whether use of different bypass methods chosen according to location of the individual lesions resulted in improved results.
For the 93 cases of ascending aortic aneurysm, the method for cardiac protection was improved by the use of continuous retrograde coronary sinus perfusion with cardioplegic blood. In sixteen cases with dissection involving the aortic arch, deep hypothermic circulatory arrest and continuous retrograde cerebral perfusion through the superior vena cava was employed for brain protection. The safe brain circulation arrest time was thus prolonged to the longest record of 81 minutes. Among the group of 93 cases, there were four operative and four hospital deaths, giving a mortality rate of 8.6% (8/93). For the 34 cases of descending aortic aneurysms, left heart bypass was employed to avoid ischemia of the heart, lungs, brain, and the abdominal organs; the operative mortality rate was 8.8% (3/34). In three cases of interrupted aortic arch, separate upper and lower body perfusion under deep hypothermia with low flow rate perfusion for the upper body provided the necessary conditions for radical surgery. In one patient with Budd-Chiari syndrome, a total corrective surgery was achieved under right heart bypass.
Validation of Two Flow Probes Using Bovine, Porcine, Ovine and Human Blood
Authors: Reagor J.A. , Delucia A. , Sutton Robin G. , Richenbacher W.E. 
Published: August 2023

In-line electromagnetic and doppler flow probes employed in extracorporeal circuits are calibrated for use with human blood. This study was performed to compare the accuracy of the Sarns Delphin II Doppler and the Medtronic Bio-Medicus electromagnetic flow probes to actual flow using bovine, porcine, ovine and human blood. The flow probes were incorporated into an in vitro extracorporeal circuit. Hematocrit, temperature and flow were randomized over ranges of 15-45% (increment 10%), 22-37°C (increment 5°C) and 1-5 L/min (interval 1 L/min), respectively. Probe flow readings were compared to the measured flow.
Flow probe readings in all species significantly correlated with actual flow (p <0.05). Doppler and electromagnetic probe flow readings significantly differed within species (p <0.001). The doppler percent error positively correlated with hematocrit (p <0.001) in all species except human. The electromagnetic percent error did not consistently correlate with hematocrit or temperature. Neither of the flow probe percent errors correlated with erythrocyte diameter or mean corpuscular volume utilizing the average population measurement. Regression equations were developed to derive actual flow from the doppler probe readings in ruminants. These data will allow investigators to select a flow probe appropriate for the experimental conditions and animal model.
Investigation of Fatigue Failure of S-65-HL “Super Tygon” Roller Pump Tubing
Authors: Snyder Edward J. , McElwee Dorothy L. , Harb Hassan M. , Cullen James A. , Tackel Ira S. , Baumgart Stephen , lskandarani Bassel , Elkind Alexander , Shaker Manal 
Published: August 2023

A failure analysis was performed on Norton S-65-HL Tygon00AE tubing. Fatigue testing was performed on four sizes of this tubing, and essentially showed how the tubing wears out. A dynamic “life hours to failure” test, which was performed on the 3/8" internal diameter (ID) size, quantified when the tubing ruptured. Based on results of laboratory testing and the institution's clinical extracorporeal membrane oxygenation (ECMO) experience, a reasonable life expectancy for the 3/8" S-65-HL Tygon® size was determined for use in this institution's neonatal ECMO system.
An understanding of the expected performance of roller pump tubing - an integral component of the ECMO system - is imperative to providing safe, effective extracorporeallife support.
Evaluation of the Thrombelastograph Targeted Coagulation Assessment
Authors: Bonness Andrew S. , Stammers Alfred H. , Huffman Suzanne M. , Ficek Suzanne J. , Brady Chad P. 
Published: August 2023

Extracorporeal circulation predisposes patients to hemorrhagic risk which may increase both homologous transfusion requirements and the need for pharmacological intervention. The aim of this study was to evaluate the efficacy of a new diagnostic coagulation assay utilizing the thrombelastograph (TEG).
Following Institutional Review Board approval, blood was drawn from healthy, non-medicated volunteers and four in vitro coagulopathic conditions were created, which included: hyperfibrinolysis (100% lysis), hypofibrinogenemia (<50 mg/dl), and both qualitative (1000 ug/ml nitroglycerin) and quantitative (<50 K/mm3) platelet abnormalities. Each of these four blood samples was then divided among four vials that contained known quantities of either: aminocaproic acid, fresh frozen plasma (FFP), platelet concentrate, or heparinase, and TEG profiles were completed.
Twenty-one samples were evaluated and the following results were obtained. Hyperfibrinolysis- 100% correction of fibrinolytic potential in the aminocaproic acid vial, but none in the other vials. Qualitative platelet dysfunction- significantly improved time to coagulation in the platelet vial but not in the FFP, heparinase or aminocaproic acid vials. Quantitative platelet dysfunction- no significant difference observed between any vials. Hypofibrinogenemia- significant improvement in the TEG index in the FFP vial (-2.7 ± 0.5) when compared to the aminocaproic acid ( -8.6 ± 2.5, p<.001), platelet (-6.5 ± 0.5, p<.01) and heparinase (-8.8 ± 2.5, p<.001) vials.
We conclude that this coagulation assessment assay may help in identifying the specific source of bleeding during surgeries where hyperfibrinolysis, hypofibrinogenemia, or qualitative platelet dysfunctions are present.
Evaluation of the Hemochron 8000 Rx/Dx System for Heparin Management
Authors: Johnson Howard D. , Morgan Marc S. , Koenig Gary R. , Utley Joe R. , Leyland Steven A. , Whittle Thomas B. , Conn John M. 
Published: August 2023

The Hemochron Rx/Dx uses an ACT and a heparin response tube to calculate the heparin dose to identify heparin sensitive/resistant patients. We evaluated the Rx/Dx system in 37 patients to determine if the ACT after the predicted heparin loading dose was adequate to initiate CPB.
The mean heparin dose calculated by the Rx/Dx was 31,700 IU ± 8,700 IU (370 IU/kg) with a mean post ACT of 463 ± 124 sec. Our standard heparin dose (400 IU/kg) would have given an additional 2,800 IU over the Rx/Dx.
Four patients (6.5%) were predicted to be heparin sensitive and all four achieved an ACT over 450 sec. Twenty-one patients (56.8%) were predicted to be resistant and yet failed to raise the ACT over 450 sec in 17 (81.0% ). Twelve patients (32.4%) were predicted to have a normal heparin response, and four (33.3%) did not achieve an ACT over 450 sec. In all, 21 patients (56.8%) did not achieve an ACT greater than 450 sec.
Each institution should evaluate their heparin loading dose and the resultant ACT. In this study, we found the number of times the Rx/Dx system did not raise the ACT over 450 sec too great to justify the additional expense.
Evaluation of a New Generation Cardioplegia Administration System
Authors: Sydzyik R. Troy , Stammers Alfred H. , Zavadil Douglas P. , Deptula Joseph J. , Christensen Kevin A. 
Published: August 2023

The delivery of cardioplegia has traditionally been constrained by the physical limitations of the mechanical devices in use, yet myocardial protective strategies may vary both according to patient condition and operative requirements. The need for a cardioplegia administration device that allows flexibility and safety is evident. The purpose of this study was to evaluate the performance of the Quest Myocardial Protection System™ (MPS) during clinically simulated conditions.
The MPS was evaluated in an in vitro setting under the following conditions: blood to crystalloid ratios (1:1, 4:1, 8:1, all blood), potassium concentrations ([K+]) of 10 and 25 mmol/L, calcium concentrations ([Ca++>l) of 1.4 and 2.8 mmol/L, and at flow rates of 100 and 300 ml/min. Predicted values from the MPS were compared with measured values, with statistically significance accepted at p<.05 level.
Significant differences were seen between measured and MPS cardioplegia delivery volumes at the 4:1, 8:1 and all blood ratios with a flow rate of 300 ml/min. There were no significant differences seen between measured and expected [K+] and [Ca++] delivery values across all combination of flow rates and ratios. Differences between delivery pressures of the MPS and measured values for flow rates of 100, 250 and 500 ml/min were 0.4, 1.2 and 7.6 mmHg respectively. The mean cardioplegia cooling time from 37°C to 9°C was 37±4.5 seconds, while rewarming from 7°C to 37°C, to 9°C, took 53±10.4 seconds.
In conclusion, the Myocardial Protection System performance characteristics were precise in ratio delivery, concen.trations of potassium agents, additive agent concentration, temperature, and pressure across all experimental conditions, with the exception of delivery volume.
Utility of In Vitro Heparin and Protamine Titration for Dosing During Cardiopulmonary Bypass Surgery
Authors: Zucker M.L. , Barrett C.L. , Bennett K. , LaDuca F.M. 
Published: August 2023

Methods used to maintain a hemostatic balance during cardiopulmonary bypass surgery include the optimization of heparin and protamine dosing. Higher heparin doses have been associated with increased bleeding, while other studies have attributed reduced blood loss and transfusion requirements to lower protamine doses. We have evaluated the use of an in vitro heparin and protamine titration system and compared it to standard dosing in patients undergoing surgery requiring cardiopulmonary bypass. Based upon the principle of the Hemochron® RxDx® system, Heparin Response Tests (HRT) and Protamine Response Tests (PRT) were performed for 40 patients undergoing cardiac surgery at three hospital centers. The Activated Clotting Time (ACT) was used to monitor adequate heparin dosing prior to placing the patient on bypass, and to monitor heparin reversal after protamine dosing. The efficacy of heparin reversal was determined using the Protamine Dose Assay (PDA-O) test. All centers used standard hospital pharmaceutical preparations of heparin and protamine.
Heparin and protamine RxDx dosing was compared to standard hospital practice for each site. Based on the HRT, the average heparin dose was not different from empirical dosing; however, individual differences were as high as 11,000 units. Only a single patient required a second heparin bolus prior to initiation of bypass. On average, the protamine dose predicted by the PRT was only 67% of the empirical protamine dose. The PDA-O test identified the need for additional protamine in 13% of patients. Patients administered additional protamine at the request of the surgical team, despite the presence of a normal PDA-O test, had no further decrease in ACT.
In summary, the in vitro HRT and PRT system did not alter the initial heparin dose yet significantly decreased the protamine doses administered. Based on prior clinical outcome studies, this reduction is expected to have a beneficial effect on postoperative bleeding and transfusion requirements.
The Design and Application of a Pediatric Centrifugal Pump
Authors: Ding Wen-xiang , Yu Xiao-qing , Su Zhao-kang , Huang Hui-min 
Published: August 2023

This centrifugal pump (CP) includes two parts: the blood pump and the driving apparatus. They are connected by six twin magnetic disc plates and driven by a magnetic DC motor (120W). The blood pump had six leaves deadlocked between two plastic discs. Six leaves were set at 30° angles, separately. In the lower chamber of the CP, there was an inlay magnetic disc, which is connected with the disc leaves by an axis. This axis was sealed by silicon rubber and a ceramic ring. The priming volume of the blood chamber was 34 ml.
In vitro testing showed that the free hemoglobin caused by the CP was much less than that caused by a roller pump after 180 min. The effect of this CP on blood cell damage was also studied in an animal model. Six goats were placed on cardiopulmonary bypass for 180 min. Perfusion flow rates were maintained between 1.5 and 2.5 L/min. The plasma free hemoglobin was lower in the CP group (6.04 mg/dL) than in the roller pump group (32.25 mg/dL), p < 0.01.
The CP has been used in ten pediatric patients undergoing cardiopulmonary bypass surgery. The patients' ages were from three to five years, and body weights were from 15 to 20 kg. Perfusion flow rates were maintained between 1.8 and 2.5 L/min, and bypass times were from 30 to 50 min. The rotation speeds were from 2000 to 2500 rpm. All the patients recovered smoothly, and no hemoglobinuria occurred.
Application of Polygeline in Pediatric Cardiac Surgery
Authors: Zhu De-Ming , Chen Hong , Wang Wei , Chen Ying 
Published: August 2023

The purpose of this study was to determine the effect of using polygeline as part of the cardiopulmonary bypass solution in pediatric cardiac surgery.
A total of 40 cases were divided into two groups, a polygeline group (H group, n=20) and a plasma group (P group, n=20). Operations were performed under routine extracorporeal circulation. The dose of polygeline or plasma used was calculated to maintain the patient's plasma colloid oncotic pressure at 10-12 mmHg.
The results showed that in the polygeline group, no patient developed allergic or coagulation disorders even after large volumes of polygeline were used (45 ml/kg). At the initiation and completion of cardiopulmonary bypass (CPB), the concentrations of calcium were higher in the H group (1.38 ± 0.19, 1.21 ± 0.11) than those (0.72 ± 0.11, 0.95 ± 0.10) in the P group. There were no other statistically significant differences between the two groups. There were no organ problems in the patients included in the study.
This study demonstrated that polygeline could be used as part of prime solution instead of plasma to keep an ideal plasma colloid oncotic pressure, reduce infections caused by blood product transfusions and lower the cost to the patients.
Berufliche Belastungen von Long-Covid-Rehabilitand*innen und
Rückkehr zur Arbeit nach einer pneumologischen
Rehabilitation
Authors: Rutsch Mercedes , Deck Ruth 
Published: August 2023

Zusammenfassung
Hintergrund Das durch SARS-CoV-2 verursachte Long Covid-Syndrom
beeinträchtigt Betroffene aufgrund von anhaltenden Symptomen und
Einschränkungen im sozialen wie beruflichen Leben. Die medizinische
Rehabilitation zielt darauf ab, Teilhabeeinschränkungen zu reduzieren
und die Erwerbsfähigkeit der Betroffenen wiederherzustellen. Bislang ist
nicht bekannt, wie sich die berufliche Situation von Long Covid-Betroffenen nach
einer pneumologischen Rehabilitation entwickelt.
Methodik Die Gesamtstudie ist als multizentrische, prospektive
Beobachtungsstudie im Mixed-Method-Design angelegt. Rekrutiert wurden
Covid-19-Rehabilitand*innen in der pneumologischen Rehabilitation im
Alter von 18 bis 65 Jahren. In dieser Auswertung wurden die Fragebogendaten von
zur Baseline erwerbstätigen Personen berücksichtigt. Die
schriftliche Befragung fand am Anfang und Ende der Rehabilitation sowie nach
sechs Monaten statt. Erhoben wurden u. a. Return to Work, berufliche
Belastungen und Veränderungen, subjektive Prognose der
Erwerbstätigkeit (SPE) und berufliche Leistungs- sowie
Arbeitsfähigkeit (WAI).
Ergebnisse Die Stichprobe umfasst N=173 Teilnehmer*innen
(68,2% weiblich) und ist im Durchschnitt 52,5 Jahre alt. 85,5%
der Rehabilitand*innen waren sechs Monate nach der Rehabilitation
arbeitsfähig und kehrten an einen Arbeitsplatz zurück. Die
Fehlzeiten, die subjektiv empfundene Leistungsfähigkeit und
Arbeitsfähigkeit verbesserten sich im zeitlichen Verlauf statistisch
signifikant (p<0,01). Die Gefahr einer frühzeitigen Berentung
besteht auch noch sechs Monate nach der Rehabilitation bei 41,3% der
Studienteilnehmer*innen. Die Teilhabeeinschränkungen reduzieren
sich im Follow-up statistisch signifikant und mit mittlerer Effektstärke
(ES=0,60, p<0,01). In der logistischen Regression erwies sich
der WAI als signifikant protektiver Prädiktor auf die Rückkehr
zur Arbeit, kognitive Corona-Symptome und hohe Werte der kognitiven Fatigue
erwiesen sich als Risikofaktoren.
Schlussfolgerungen Der Großteil der Rehabilitand*innen ist
ein halbes Jahr nach einer pneumologischen Rehabilitation erwerbstätig,
obwohl auch über die Rehabilitation hinaus von anhaltenden Symptomen und
einer beeinträchtigten Arbeitsfähigkeit berichtet wird. In der
Rehabilitation Erwerbstätiger könnten berufsbezogene Elemente,
beispielsweise die Klärung beruflicher Fragen und Vorbereitung auf
berufliche Anforderungen (z. B. Konzentration, Stress,
körperliche Anforderungen), einen nachhaltigen Return to Work
unterstützen.