Double Row Research Articles

Complications following surgical management of Haglund's triad: A retrospective, single-center analysis

BackgroundHaglund's triad consists of Haglund's deformity, insertional Achilles tendinosis, and retrocalcaneal bursitis and is most commonly managed surgically through Haglund's resection, bursectomy, and Achilles tendon detachment-reattachment using a central tendon-splitting approach stabilized with a double row suture construct. This procedure has demonstrated consistently good outcomes; however, we have anecdotally identified a higher complication rate performing this surgery compared with the published literature. Accordingly, we sought to evaluate this further. MethodsWe performed a retrospective electronic medical record review of 44 consecutive patients (10 men, 34 women) who underwent surgical correction of Haglund's triad. Patient age, gender, laterality, body mass index, follow-up duration, complications encountered, and revision surgery performed were analyzed. ResultsSignificant differences were identified for gender and incidence of complications (p = 0.01424), with women having a greater incidence of complications than men and duration of follow-up (p = 0.0432) where women endured a longer follow-up period. No other significant differences for complications were identified for age (p = 0.192), laterality (p = 0.5535), or body mass index (p = 0.9532) irrespective of gender. Complications occurred in 50 % of patients with most complications persisting at the final follow-up. ConclusionWe identified a significantly greater incidence of complications for women compared to men for operative management of Haglund's triad regardless of age, laterality, or body mass index. Further analysis of the effect gender has on operative management of Haglund's triad seems warranted so that measures to mitigate complications can be developed, especially since complications persisted for those patients who encountered them which negatively affected their outcomes. Level of EvidenceIII-Therapeutic study: Retrospective comparative analysis at a single institution CategoryRearfoot and Ankle Reconstruction

Soil fertility in silvopastoral systems integrating tree legumes with signalgrass (Urochloa decumbens Stapf. R. Webster)

Silvopastoral Systems (SPS) can increase overall productivity and generate continuous income in order to stimulate simultaneous growth and development of trees, forage and livestock. Moreover, the SPS with tree legumes would be important for add nutrients to the system, mainly N, and ensure the soil health and quality. Soil properties were assessed in two SPS, implanted in 2011, using tree legumes and Urochloa decumbens Stapf. R. Webster (Signalgrass). Treatments were Signalgrass + Mimosa caesalpiniifolia Benth (Sabia) and Signalgrass + Gliricidia sepium (Jacq.) Kunth ex Walp. (Gliricidia), and they were allocated in a randomized complete block design, with three replications. Soil was sampled in 2013, 2017, and 2018, at 0, 4, and 8 m along transects perpendicular to tree double rows, from 0- to 20- and 20- to 40-cm layers. Soil chemical properties included pH, P, K+, Ca2+, Mg2+, Al3+, H++Al3+, cation exchange capacity (CEC), and base saturation. In addition, light fraction of soil organic matter (LF-SOM), soil basal respiration (SBR), and natural abundance of 13C of the respired CO2 (δ13C-CO2) were analyzed. Soil pH (5.3, 5.2, 5.1), P (11.3, 7.2, 3.6 mg dm-3), and CECeffective (5.8, 5.1, 5.0 cmolc dm-3) decreased (P < 0.05) along the years 2013, 2017, and 2018, respectively. In 2018, the LF-SOM and δ13C-CO2 was greater in Sabia (1.1 g kg-1 and -16.4‰) compared to Gliricidia (0.7 g kg-1 and -18.2‰). Silvopastoral systems reduced soil fertility regardless of the tree legume species used as result of biomass nutrient stock, without maintenance fertilization. Sabia had greater deposition of LF-SOM, without increasing SBR, providing potential for microbial C use efficiency. Enriched C-CO2 isotope composition shows an efficient SOM oxidize in SPS with Gliricidia or Sabia. This information can contribute to the assessments related to CO2 balance and C retention. Both SPS contribute to C sequestration.

English

Drought is a highly important abiotic stress that affects crops around the world and especially under the Mediterranean climate. This study is focused on strawberry, an important species around the Mediterranean that is suitable for family-owned smallscale businesses. This study aimed to determine the effects of conventional deficit irrigation and fixed partial root drying techniques on the evapotranspiration (ET), yield and quality of Rubygem strawberry species. Strawberry seedlings were planted in the greenhouse in a double row at a planting distance of 30×30 cm. Irrigation was carried out by drip irrigation. The control - full irrigation was based on measurements taken from an A-Class Evaporation Pan. Three conventional deficit irrigation (DI80, DI60 and DI40) and four fixed partial root drying (FPRD100, FPRD80, and FPRD60 FPRD40) were examined. Irrigation water quantities were applied at the 100% (FPRD100/FULL), 80% (DI80 and FPRD80), 60% (DI60 and FPRD60) and 40% (DI40 and FPRD40) levels. The amount of irrigation water ranged between 199.17 and 452.92 mm. It was found that the various water levels affected the ET and the yield (Y). In general, as the amount of water decreased, the ET also decreased. The ET, Y, water use efficiency (WUE) and irrigation water use efficiency (IWUE) were significantly affected by irrigation treatments (LSD 5%). The yield values are ranked from high to low as FULL > FPRD100 > FPRD80 > DI80 > DI60 > FPRD60 > FPRD40 > DI40. As expected, WUE and IWUE values were higher under deficit irrigation levels i.e., DI80, DI60, DI40, FPRD80, FPRD60, and FPRD40. Fruit quality parameters (width, height and average weight) increased with the increase in the amount of applied irrigation water. In addition, fruit firmness values and total phenolic compounds were significantly affected by irrigation level. The results showed that different irrigation levels (100%, 80%, 60% and 40%) affected the yield and yield parameters of strawberry plants. In general, it has been found that, the yield and quality are negatively affected with increases in water deficit (DI40 and FPRD40 treatments). However, the results showed that the fixed partial root drying technique is superior to conventional deficit irrigation applications. As a result of the research, mainly FPRD80 and then DI80, DI60 and FPRD60 are recommended for strawberry cultivation, especially in arid and semiarid regions, depending on the availability of water

Biomechanical comparison of suture bridge rotator cuff repair with and without dermal allograft pledgets

BackgroundOne method to augment rotator cuff repair is to pass dermal allograft pledgets along the sutures that bridge from the medial to the lateral row. It remains unclear whether this augmentation method alters repair biomechanics. MethodsThis was a controlled laboratory study. After an a priori power analysis, nine pairs of rotator cuffs underwent double row suture bridge rotator cuff repair, half randomized to augmentation with dermal allograft pledgets passed along the suture bridge sutures. Repairs were then mounted on a material testing system and loaded cyclically 500 cycles to mesure applied force and displacement. Repairs then underwent ultimate failure testing and stiffness, ultimate failure force, and ultimate failure displacement were measured. Paired t-tests were performed to compare between groups. ResultsThere were no differences between groups in construct gapping with cyclic loading after 500 cycles (p = 0.885). There no differences between the augmented and control groups in yield force (103.5 ± 5.0 vs. 101.4 ± 5.9 N, respectively, p=0.183), stiffness (94.2 ± 13.9 vs. 90.9 ± 13.8, p=0.585), or ultimate failure force (255.3 ± 65.8 vs. 285.3 ± 83.2, p=0.315). There were no differences between groups in failure modes, with most specimens failing by cuff tissue tearing within or medial to the construct. ConclusionThe addition of dermal allograft pledgets does not positively or negatively influence the time-zero biomechanical characteristics of double-row suture bridge rotator cuff repair.

Experimental Study on Energy Dissipation Performance of SPA Shear Plate Metal Damper Based on Jacket Platform

Aiming at the problem of excessive vertical vibration caused by seismic primary waves in jacket structures located in seismic zones in China, a new type of shear plate metal damper with upper and lower elliptical openings (SPA) is proposed in this paper. The seismic model test is carried out to compare the shear plate metal damper with three traditional opening forms, central elliptical opening, single row opening, and double row opening, and the hysteretic curve, skeleton curve, and cyclic hysteretic energy dissipation capacity are analyzed. The results show that the energy dissipation performance of the new shear plate metal damper with upper and lower elliptical openings proposed in this paper is better than that of the other three types of dampers.

Different types of rotator cuff tear morphology do not affect post-repair clinical outcomes in large to massive tears

ObjectivesThe primary aim of this current study is to evaluate the effects of rotator cuff tear morphology on clinical outcomes in large to massive tears, using a modified version of the existing classification system, with specific focus on tear symmetry and use of margin convergence. MethodsPatients who underwent arthroscopic repair of large to massive, full thickness rotator cuff tears were retrospectively analysed. The tear pattern was classified at the time of surgery as Type IA, Type IB, Type IIA, and Type IIB according to tear symmetry and direction of maximum tear diameter, with Type I being symmetrical and Type II being asymmetrical. Type IA (U-shaped) had greater mediolateral (ML) than anteroposterior (AP) diameter while Type IB (crescent shaped) had greater AP than ML diameter. Type IIA tears have an anterior extension towards the rotator interval while IIB tears have a posterior extension into the infraspinatus, similar to AP L-shaped tears established in the literature. Type I tears were typically repaired from medial to lateral while Type II tears were repaired diagonally. All types were repaired using double row technique, with the addition of margin convergence for Types IA and IIB, which had larger tears in the medial and lateral directions. Primary outcome measures were Oxford Shoulder Score, Constant Shoulder Score, University of California at Los Angeles Shoulder Score followed-up at 6, 12, and 24-months as well as retear rates at latest follow-up. ResultsIn total, 109 patients were included in the study with a mean age of 65.5 ​± ​9.4. The prevalence of each tear morphologies from Type IA to IIB was 22.0 ​%, 34.9 ​%, 27.5 ​%, and 15.6 ​%, respectively. All four groups showed statistically significant improvement from pre-operative scores in all 3 outcome measures at 24 months (p ​< ​0.001 for all). No significant difference in primary outcome measures or retear rates was detected between all 4 groups. ConclusionThis study found that different types of cuff tear morphology, despite affecting surgical repair technique, does not influence clinical outcomes post-arthroscopic rotator cuff repair at mid-term follow-up. Level of evidenceRetrospective Cohort study, Level III.

New species and records of Pseudochironomini Sæther, 1977 (Diptera, Chironomidae) from the Dominican Republic.

Pseudochironomini is a relatively small and poorly-studied tribe of subfamily Chironominae (Diptera, Chironomidae). Pseudochironomusruthae Andersen & Baranov sp. nov. is described and figured, based on a single male collected in a light trap at Matadero, Dominican Republic. The species can be separated from its congeners by the combination of the following characters: wing without dark bands, dorsocentrals in partly double row and apex of superior volsella rounded. The species is the first Pseudochironomus species to be formally recorded and described from the Caribbean. In addition, a new record of Manoapahayokeensis Jacobsen & Perry, 2002 from the Dominican Republic is given. One specimen was DNA-barcoded and the barcode is given.

A Mixed-Integer Programming Formulation for a Simplified Model of the Double Row Layout Problem

The double row layout problem (DRLP) is to assign facilities on two rows in parallel so that the total cost of material handling among facilities is minimized. Since it is vital to save cost and enhance productivity, the DRLP plays an important role in many application fields. Nevertheless, it is very hard to handle the DRLP because of its complex model. In this paper, we consider a new simplified model for the DRLP (SM-DRLP) and provide a mixed integer programming (MIP) formulation for it. The continuous decision variables of the DRLP are divided into two parts: start points of double rows and adjustable clearances between adjacent facilities. The former one is considered in the new simplified model for the DRLP with the purpose of maintaining solution quality, while the latter one is not taken into account with the purpose of reducing computational time. To evaluate its performance, our SM-DRLP is compared with the model of a general DRLP and the model of another simplified DRLP. The experimental results show the efficiency of our proposed model.

Single-row versus double-row arthroscopic repair in the treatment of rotator cuff tears. A systematic review.

The purpose of this study is to perform a systematic review of the scientific literature to compare single and double row techniques for rotator cuff tears in terms of functional, pain improvement and structural healing of the tendon. In order to carry out the research, a systematic selection of scientific articles has been made by consulting PubMed and The Cochrane Library databases. The articles included in the present study compare the single-row and double-row techniques, with publication date between 2016 and 2021. Diverse results are observed in the UCLA, SST, Constant and ASES assessment scales and in the range of mobility, therefore, the superiority of one technique in terms of functional results is not established. The double row technique may show superiority in the strength variable, although there is a methodological variability in its measurement. The double-row technique may be related to more intense postoperative pain, while the single-row technique to residual shoulder pain. However, the variables strength and pain show non-homogeneous or coincident data. The superiority of the double row repair in the structural healing of the tendon and a lower re-tear rate than the single row technique is established with statistically significant results, being the most homogeneous and coincident studies.

Comparative study on flexural behavior of steel-UHPC composite beams and steel-ordinary concrete composite beams in the negative moment zone

To compare the flexural behavior of steel-UHPC (ultra-high performance concrete) composite beams and steel-ordinary concrete composite beams under a negative bending moment, 4 steel–concrete composite beams were tested under a negative bending moment. The effects of slab materials and stud number on flexural failure mode, crack development, stiffness ductility, cracking load and ultimate flexural capacity of composite beams were investigated. The results show that the UHPC can significantly improve the flexural behavior of steel–concrete composite beams under a negative bending moment. For the steel-UHPC composite beams with a single row, the cracking load is 135 % higher than that of steel-ordinary concrete composite beams, and the overall stiffness increased by 108 %, the yield stiffness increased by 40 %, the ultimate flexural capacity increased by 9 %, and the ductility increased by 133 %; for the steel-UHPC composite beams with double row, the cracking load is 102 % higher than that of the steel-normal concrete composite beam, the overall stiffness is increased by 34 %, the yield stiffness is increased by 44 %, the ultimate flexural capacity is increased by 6 %, and the ductility is increased by 75 %. Increasing the number of studs can significantly improve the overall ductility of composite beams, while the improvement of cracking load, overall stiffness, and ultimate flexural capacity of composite beams is not significant. The cracking load, overall stiffness, yield stiffness, ultimate load, and ductility of double-row stud steel–concrete composite beams are 23 %, 53 %, 13.2 %, 12 %, and 115 % higher than those of single-row stud steel–concrete composite beams, respectively; while those of double-row steel-UHPC composite beams increases by 6 %, 8 %, 16 %, 8 % and 62 % higher than those of single-row stud steel–concrete composite beams, respectively. A simplified calculation model for the flexural capacity of steel-UHPC composite beams in a negative moment zone was established.

No difference in biomechanical properties of simple, horizontal mattress, and double row repair in Bankart repair: a systematic review and meta-analysis of biomechanical studies

BackgroundArthroscopic Bankart repair is the most common procedure in patients with anterior shoulder instability. Various repair techniques using suture anchors have been used to improve the strength of fixation and surgical outcomes in arthroscopic Bankart surgery. However, evidence regarding which method is superior is lacking. This systematic review and meta-analysis study was designed to compare the biomechanical results of simple versus horizontal mattress versus double-row mattress for Bankart repair.MethodsA systematic search of the MEDLINE, Embase, and Cochrane Library databases was performed to identify comparative biomechanical studies comparing the simple, horizontal mattress, and double-row techniques commonly used in Bankart repair for anterior shoulder instability. Biomechanical results included the ultimate load to failure, stiffness, cyclic displacement, and mode of failure after the ultimate load. The methodological quality was assessed based on the Quality Appraisal for Cadaveric Studies (QUACS) scale for biomechanical studies.ResultsSix biomechanical studies comprising 125 human cadavers were included in this systematic review. In biomechanical studies comparing simple and horizontal mattress repair and biomechanical studies comparing simple and double-row repair, there were no significant differences in the ultimate load to failure, stiffness, or cyclic displacement between the repair methods. The median QUACS scale was 11.5 with a range from 10 to 12, indicating a low risk of bias.ConclusionThere was no biomechanically significant difference between the simple, horizontal mattress, and double-row methods in Bankart repair. Clinical evidence such as prospective randomized controlled trials should be conducted to evaluate clinical outcomes according to the various repair methods.Level of evidenceSystematic review, Therapeutic level IV.

Biomechanical stability of oblique lateral interbody fusion combined with four types of internal fixations: finite element analysis.

Objective: Using finite element analysis to identify the optimal internal fixation method for oblique lateral lumbar interbody fusion (OLIF), providing guidance for clinical practice. Methods: A finite element model of the L4 - L5 segment was created. Five types of internal fixations were simulated in the generated L4-L5 finite element (FE) model. Then, six loading scenarios, i.e., flexion, extension, left-leaning, right-leaning, rotate left, and rotate right, were simulated in the FE models with different types of fixations. The biomechanical stability of the spinal segment after different fixations was investigated. Results: Regarding the range of motion (ROM) of the fused segment, OLIF + Bilateral Pedicle Screws (BPS) has a maximum ROM of 1.82° during backward bending and the smallest ROM in all directions of motion compared with other models. In terms of the von Mises stress distribution on the cage, the average stress on every motion direction of OLIF + BPS is about 17.08MPa, and of OLIF + Unilateral Vertebral Screw - Pedicle Screw (UVS-PS) is about 19.29MPa. As for the von Mises stress distribution on the internal fixation, OLIF + BPS has the maximum internal fixator stress in left rotation (31.85MPa) and OLIF + Unilateral Pedicle Screw (UPS) has the maximum internal fixator stress in posterior extension (76.59MPa). The data of these two models were smaller than those of other models. Conclusion: OLIF + BPS provides the greatest biomechanical stability, OLIF + UPS has adequate biomechanical stability, OLIF + UVS-PS is inferior to OLIF + UPS synthetically, and OLIF + Double row vertical screw (DRVS) and Individual OLIF (IO) do not present significant obvious advantages.

Plant Density Recommendations and Plant Nutrient Status for High Tunnel Tomatoes in Virginia

Open-field tomatoes in Virginia are traditionally planted in a single row with 2 ft (0.60 m) of in-row spacing, resulting in a plant density of 4356 plants per acre (10,890 plants/ha). However, there has been increasing interest among small and medium-sized farmers in high tunnel production. In order to be profitable, farmers must maximize their yield per unit area and take advantage of the potential benefits of producing under high tunnels. A common approach under greenhouse conditions is to increase the planting density to enhance yield per area. However, high tunnel farmers often extrapolate open-field practices to their high tunnels as they believe both systems are closer related together than to greenhouse production. In those cases, high tunnel farmers could potentially be neglecting yield increases due to their planting density selection. Additionally, irrigation and fertilization management (fertigation) under high tunnels tend to be more efficient than open-field systems, as the frequency of application is increased with a lower volume per application. A higher efficiency of fertigation could alter plant yield responses, especially under traditional planting-density systems. Hence, this study aimed to identify the effect of high planting density on high tunnel tomatoes and their nutrient status on the Eastern Shore of Virginia. The experiment was established on a completely randomized block design with four replications, with 20 ft (6.09 m) experimental plots. We evaluated the combination of two in-row distances and single and double planting rows, with treatments consisting of 2 ft of in-row distance in a single row (4356 plants/acre—current open-field recommendation), 1.5 ft (0.45 m) of in-row distance in a single row (5808 plants/acre [14,520 plants/ha]), 2 ft of in-row distance in a double row (8712 plants/acre [21,780 plants/ha]), and 1.5 ft of in-row distance in a double row (11,616 plants/acre [29,040 plants/ha]). Summer-grown tomatoes produced on the Eastern Shore of Virginia under high tunnel conditions should be planted with 2 ft of in-row spacing and with a single row of plants per planting bed. Increasing the plant density or modifying the current recommended plant distribution could result in yield losses per plant between 32% and 46% and substantial increases in production costs compared with the traditional planting density. Throughout all treatments, tomato plants did not show deficient nutrient status. We hypothesized that irrigation water and pollination were the limiting factors that promoted a decrease in yield per plant for the high-density treatments.

Phlebotomine sand flies (Diptera, Psychodidae) from Pha Tong cave, Northern Thailand with a description of two new species and taxonomical thoughts about Phlebotomus stantoni.

In South-East Asia, Thailand is the country with the highest number of human autochthonous cases of leishmaniases mostly due to Leishmania martiniquensis. Their transmission remains unresolved to date even though sand flies are known vectors of leishmaniases. As such, we focused a study on the sand fly fauna of a cave in Thailand to explore the biodiversity of potential Leishmania vectors. We carried out an inventory in Pha Tong cave. We caught and identified 570 Phlebotomine sand flies (452 females and 118 males) and identified 14 species belonging to the genera Phlebotomus, Idiophlebotomus, Chinius, Sergentomyia and Grassomyia. Among these 14 species, two could not be related to known sand fly species. Herein, we propose the description of two new sand fly species, previously unknown to science. The first new species, Phlebotomus shadenae n. sp. is a sand fly of the subgenus Anaphlebotomus. It is morphologically close to Ph. stantoni, a species widely distributed throughout Southeast Asia. However, it differs by the length of the genital filaments in males or by the length of the ducts of the spermathecae in females as well as the high divergence of cytochrome b sequences. Additionally, we revised the systematics of the subgenus Anaphlebotomus and reinstated, by examination of its holotype, the validity of Ph. maynei, an Indian wrongly considered as a synonym of Ph. stantoni in the past. The second new species, Sergentomyia maiae n. sp., differs from a species in the same group, Se. barraudi, by an original cibarial double row of vertical teeth as well as by molecular data. We propose the description of two new sand fly species for Science with morphological and molecular evidence. Ph. shadenae n. sp. was also found to be distributed in the south of Thailand and in Laos. Future studies need to determine whether these two species can play a role as vectors of Leishmania parasites, Trypanosomatids or Phlebovirus. Most of the species caught in the present study are strictly cavernicolous except Grassomyia sp. and a few Sergentomyia.

Agronomic Response of Soybean Accession at Two Spacings

The key to optimizing plant productivity is superior plant varieties combined with proper plant management. The purpose of this study was to learn about the responses of various soybean accessions to different spacings. During the dry season of 2019, the research was conducted in Genteng, Banyuwangi research station. The study employed a split plot design with two factors, which was repeated three times. The main plot was the planting method: (1). 2:1 double rows = 50 cm x (30 cm x 15 cm) (2) Single row: 30 cm x 15 cm spacing. 15 soybean accessions were used as sub-plots. Six accessions have the potential to produce seeds greater than 3 t ha-1 based on productivity per hectare. Differences in plant spacing influenced plant height, internode length, number of branches, and seed weight. Longer stems and nodes distinguished the single row. The seed yield per plant was higher in double rows than in single rows.

Numerical Investigation into Effect Section Geometry parameters of Floating Breakwaters in single and double rows on its Hydrodynamics performance

Numerical Investigation into Effect Section Geometry parameters of Floating Breakwaters in single and double rows on its Hydrodynamics performance

Numerical Simulation and Analysis of Double Row Pile Anchor Composite Support Structure based on FLAC3D

Numerical Simulation and Analysis of Double Row Pile Anchor Composite Support Structure based on FLAC3D

Adjusting spatial use to establish productive and stable Elymus nutans monocultures and mixed sowing systems

Community arrangement plays a critical role in maintaining forage community production and stability. To explore reasonable management for efficient community production in alpine regions, three monoculture communities composed of Elymus nutans, Cross row (S_C), Double row (S_D), and Single Row (S_R), and three mixed communities consisting of Elymus nutans and Onobrychis viciifolia, Broadcast(M_B), Dependent row (M_D) and Independent row (M_I) were established in Tianzhu County on the Qinghai Tibetan Plateau during 2018–2019. The results showed S_C was the most productive monoculture community, with less intraspecific competitiveness and higher population density after establishment, which could reduce the influence of lodging on yield loss. The maximum forage yield was attained at the end of 2018 (5187.6 kg·ha−1) and August 2019 (26190.9 kg·ha−1). In mixed communities, the relationship of natural height between E. nutans and O. viciifolia was relatively stable, but growth rate displayed asynchronous traits. Besides, mixed communities had higher lodging resistance compared with monoculture communities; E. nutans showed higher competitiveness than O. viciifolia, but O. viciifolia competivity when the community natural height decreased. M_B (3015.3 kg·ha−1 in 2018; 4804.6 kg·ha−1 at the flowering of 2019), and M_D (7686.2 kg·ha−1 in 2019) had better performance in forage yield. Our study has demonstrated the feasibility of adjusting plant spatial arrangements as a means to enhance forage production in alpine regions. It is crucial to consider the interaction of growth rates, as this factor determines the optimal utilization time for monocultural and mixed communities. Additionally, this study highlights the influence of changes in sowing patterns on forage growth and yield, while enriching the grassland establishment mode, thus supporting the development of sustainable livestock systems in the Qinghai Tibet Plateau.

Film Cooling on Turbine Vane Endwalls With Different Inlet Cooling Configurations: Experimental and Computational Results

Abstract A comparative study of turbine endwall film cooling resulting from three different cooling configurations in front of the passage inlet was conducted. The three inlet cooling configurations considered in this study were a conventional continuous slot, double rows of discrete film holes, and an interrupted slot with a backward-facing step. Pressure sensitive paint (PSP) was sprayed over the endwall surfaces to map adiabatic cooling effectiveness contours and five-hole probe and thermocouple measurements were implemented to assess aero-thermal fields at the passage exit. The evolution of cooling effectiveness was compared across a full range span of coolant flow rates of 0.3−1.8% in a real engine. Additionally, complex flow structures inside the passage due to interactions of coolant with mainstream flows were visualized using computational fluid dynamics (CFD) simulations to support the observed coolant coverage patterns. A side-by-side comparison of CFD simulations against experiments was made as well to evaluate the reliability of conventional turbulence modeling methods in such a complex flow. The continuous slot was found to produce the highest cooling effectiveness values while the double-row holes offered the most uniform coolant coverage, leading to spreading out of the coolant jets downstream of the passage throat and even beyond the trailing edge of the passage for coolant injection rates higher than 1.0%. Supported by the CFD-predicted flow structures and measured aerodynamic losses, the injection from the double-row holes weakened the passage secondary flows and thus caused the lowest aerodynamic loss. On the contrary, the interrupted slot enhanced the secondary flows due to the backward step, resulting in the highest flow loss.

“Double Row Rip-Stop” Arthroscopic Repair Technique for Acute, Retracted Rotator Cuff Tears

Acute, retracted rotator cuff tendon tears are important to recognize and can present unique technical challenges to repair. Various arthroscopic techniques and suture configurations have been proposed for repair of acute tears with aims to maximize the repair footprint and optimize tendon fixation. The double row rip-stop configuration was designed and has been used for rotator cuff repair due to its potential advantages related to suture pullout, footprint reapproximation and load sharing. The purpose of this article is to present the author’s arthroscopic technique for repair of acute, retracted rotator cuff tendon tears using a double-row, rip-stop suture configuration. The indications and authors’ preferred arthroscopic technique for biceps tenodesis are also discussed.