The Biopolymer Active Surface for Optical Fibre Sensors.

Optical fibre sensors have the potential to be overly sensitive and responsive, making them useful in various applications to detect the presence of pollutants in the environment, toxic gasses, or pesticides in soil. Deoxyribonucleic acid (DNA) as biopolymer active surfaces for fibre sensors can be designed to detect specific molecules or compounds accurately. In the article, we propose to use an optical fibre taper and DNA complex with surfactant-based sensors to offer a promising approach for gas detection, including ammonia solution, 1,4 thioxane, and trimethyl phosphate imitating hazardous agents. The presented results describe the influence of the adsorption of evaporation of measured agents to the DNA complex layer on a light leakage outside the structure of an optical fibre taper. The DNA layer with additional gas molecules becomes a new cladding of the taper structure, with the possibility to change its properties. The process of adsorption causes a change in the layer's optical properties surrounding a taper-like refractive index and increasing layer diameter, which changes the boundary condition of the structure and interacts with light in a wide spectral range of 600-1200 nm. The research's novelty is implementing a DNA complex active surface as the biodegradable biopolymer alignment for optical devices like in-line fibre sensors and those enabled for hazardous agent detection for substances appearing in the environment as industrial or even warfare toxic agents.

Experimental study on implant-abutment locking force and abutment subsidence in a pure Morse taper connection implant system.

OBJECTIVES: This test aimed to investigate the factors affecting the locking force between the implant and abutment and the amount of abutment subsidence in pure Morse taper connection implant systems. METHODS: With reference to the Bicon implant abutment connection design, different types of implant specimens and their corresponding types of abutments were fabricated. The implant-abutment locking taper was uniformly 1.5°. The locking depths were 1.0, 2.0, and 3.0 mm. The diameters of the locking column were 2.5, 3.0, and 3.5 mm. The thicknesses of the outer wall of the implant were 0.15 and 0.30 mm. The loading forces of the testing machine were 200, 300, and 400 N. At least 10 specimens of each group of implant-abutment were used. All specimens were loaded in the same manner using a universal testing machine (finger pressure + specified loading force, five times). The total height of the implant-abutment was measured before finger pressure, after finger pressure, and after the testing machine was loaded for five times to calculate the amount of sinking of the abutment. Finally, the implant and abutment were pulled apart using the universal testing machine, and the subluxation force was observed and recorded. RESULTS: The test loading force, locking depth, and locking post diameter had an effect on the implant-abutment locking force and abutment subsidence. The implant-abutment locking force increased with the increase in the test loading force, locking depth, and locking post diameter (R=0.963, 0.607, and 0.372, respectively), with the test loading force having the most significant effect. Abutment subsidence increased with the increase in test loading force (R=0.645) and decreased with the increase in locking depth and locking post diameter (R=-0.807 and -0.280, respectively), with locking depth having the most significant effect on abutment subsidence. No significant correlation was found between the thickness of the outer wall of the implant and the change in the magnitude of the implant-abutment locking force. However, an increase in the thickness of the outer wall of the implant decreased the amount of abutment subsidence, which was inversely correlated. CONCLUSIONS: The locking force of the implant-abutment can be increased by adjusting the design of the pure Morse taper connection implant⁃abutment connection, increasing the locking depth and locking post diameter, and increasing the amount and number of times the abutment is loaded during seating. Problems, such as loosening or detachment of the abutment, can be reduced. The recommended abutment to be loaded should be no less than five times during seating to prevent the abutment from sinking and causing changes in the occlusal relationship in the later stages. Preliminary occlusal adjustments should only be conducted in the early stages of the use of temporary restorations, and final restorations and occlusal adjustments are recommended to be performed after using the abutment for a period of time.

Mechanical Behavior of Five Different Morse Taper Implants and Abutments with Different Conical Internal Connections and Angles: An In Vitro Experimental Study.

The present study evaluated the mechanical behavior of five designs of Morse taper (MT) connections with and without the application of loads. For this, the detorque of the fixing screw and the traction force required to disconnect the abutment from the implant were assessed. A total of 100 sets of implants/abutments (IAs) with MT-type connections were used, comprising five groups (n = 20/group): (1) Group Imp 11.5: IA sets with a cone angulation of 11.5°; (2) Group SIN 11.5: with a cone angulation of 11.5°; (3) Group SIN 16: with a cone angulation of 16°; (4) Group Neo 16: with a cone angulation of 16°; and (5) Group Str 15: with a cone angulation of 15°. All sets received the torque recommended by the manufacturer. After applying the torque, the counter torque of the fixing screws was measured in ten IA sets of each group without the application of cyclic loads (frequencies ≤ 2 Hz, 360,000 cycles, and force at 150 Ncm). The other ten sets of each group were subjected to cyclic loads, after which the detorque was measured. Afterwards, the force for disconnection between the implant and the abutment was measured by traction on all the samples. The untwisting of the abutment fixation screws showed a decrease in relation to the initial torque applied in all groups. In the unloaded samples, it was found to be -25.7% in Group 1, -30.4% in Group 2, -36.8% in Group 3, -29.6% in Group 4, and -25.7% in Group 5. After the applied loads, it was found to be -44% in Group 1, -43.5% in Group 2, -48.5% in Group 3, -47.2% in Group 4, and -49.8% in Group 5. The values for the IA sets were zero for SIN 16 (Group 3) and Neo16 (Group 4), both without and with loads. In the other three groups, without loads, the disconnection value was 56.3 ± 2.21 N (Group 1), 30.7 ± 2.00 N (Group 2), and 26.0 ± 2.52 N (Group 5). After applying loads, the values were 63.5 ± 3.06 N for Group 1, 34.2 ± 2.45 N in Group 2, and 23.1 ± 1.29 N in Group 5. It was concluded that in terms of the mechanical behavior of the five designs of MT IA sets, with and without the application of loads, the Imp 11.5, SIN 11.5, and Srt 15 groups showed better results compared to the SIN 16 and Neo 16 groups, showing that lower values of cone angulation increase the friction between the parts (IA), thus avoiding the need to maintain the torque of the fixing screw to maintain the union of the sets.

Characterization of Micro-Threaded Stem Taper Surfaces of Cementless Hip Endoprostheses.

We investigated micro-threaded stem taper surface and its impact on premature failures, aseptic loosening, and infection in cementless hip endoprostheses. Our study focused on the fretting, and crevice corrosion of micro-threaded tapers, as well as the characterization of the microstructure and surface properties of two new and three retrieved Zweymüller stem tapers. The retrieved samples were selected and examined based on the head-stem taper interface being the sole source of modularity with a metallic component, specifically between the Ti alloy taper stem and the ceramic head. To determine the surface chemistry and microstructures of both new and retrieved hip endoprostheses stem taper titanium alloy, scanning -electron microscopy (SEM) was employed for morphological and microstructural analyses. Energy dispersive spectroscopy (EDS) was utilized for characterizing chemical element distribution, and electron backscattered diffraction (EBSD) was used for phase analysis. The roughness of the micro-threated stem tapers from different manufacturers was investigated using an optical profilometer, with standard roughness parameters Ra (average surface roughness) and Rz (mean peak to valley height of the roughness profile) being measured. Electrochemical studies revealed no fretting corrosion in retrieved stem tapers with ceramic heads. Consequently, three retrieved tapers and two new ones for comparison underwent potentiodynamic measurements in Hank's solution to determine the corrosion rate of new and retrieved stem taper surfaces. The results showed a low corrosion rate for both new and prematurely failed retrieved samples due to aseptic loosening. However, the corrosion rate was higher in infected and low-grade infected tapers. In conclusion, our study suggests that using ceramic heads reduces taper corrosion and subsequently decreases the incidence of premature failures in total hip arthroplasty.

Evaluation of the Efficacy of Neo-endo, Hyflex Re-treatment File Systems and H-Files for Removing Gutta-Percha From Root Canal Treated Tooth by Using Stereomicroscope-An In Vitro Study.

Aim: To evaluate the efficacy of Neo-endo, Hyflextm retreatment file systems, and H-files for removing gutta-percha from root canal treated tooth. Materials and Methods: Thirty extracted single-rooted human teeth with a single canal were opted. The shaping of the root canals was done with pro-taper universal files and later obturated. The samples were grouped based on the file system chosen for removing the obturating material: Group I-H-files; Group II-Neo-endo retreatment files; Group III-Hyflex™ retreatment files. The quantity of remaining gutta-percha still present after the retreatment procedure was assessed under a stereomicroscope. One-way Analysis of Variance (ANOVA) was used to statistically analyze the data. Results: Hyflex™ files left less remaining filling material than with Neo-endo and H-files. Conclusion: The Hyflex™ retreatment files were most efficient in removing the gutta-percha from the root canal.

Applying taper function models for black locust plantations in Greek post-mining areas.

A key process in forest management planning is the estimation of tree volume and, more specifically, merchantable volume. The ability to predict the cumulative stem volume relative to any upper stem diameter on standing trees or stands is essential for forest inventories and the management of forest resources. In the 1980s, the Hellenic Public Power Corporation (HPPC) started the rehabilitation of lignite post-mining areas in Greece by planting mainly black locust (Robinia pseudoacacia, L.). Today, these plantations occupy an area of approximately 2570 ha, but the stem volume has not yet been estimated. Therefore, we aimed to estimate the over- and under-bark stem volume using taper function models for 30 destructively sampled trees. Of the nineteen calibrated fixed-effects models, Kozak's (2004) equation performed best for both the over-bark and under-bark datasets, followed by Lee's (2003) and Muhairwe's (1999) equations. Two fixed effect models were compared with fitted coefficients from Poland and the United States confirming that the local model fits were better suited, as the foreign model coefficients caused an increase in root mean square error (RMSE) for stem diameter predictions of 13% and 218%, respectively. The addition of random effects on a single-stem basis for two coefficients of Kozak's (2004) equation improved the model fit significantly at 86% of the over-bark fixed effect RMSE and 69% for the under-bark model. Integrated taper functions were found to slightly outperform three volume equations for predictions of single stem volume over and under bark. Ultimately it was shown that these models can be used to precisely predict stem diameters and total stem volume for the population average as well as for specific trees of the black locust plantations in the study area.

To wean or not to wean: proton pump inhibitor management after anti-reflux surgery amongst foregut experts.

BACKGROUND: Most patients undergoing anti-reflux surgery (ARS) have a history of preoperative proton pump inhibitor (PPI) use. It is well-established that ARS is effective in restoring the anti-reflux barrier, eliminating the ongoing need for costly PPIs. Current literature lacks objective evidence supporting an optimal postoperative PPI cessation or weaning strategy, leading to wide practice variations. We sought to objectively gauge current practice and opinion surrounding the postoperative management of PPIs among expert foregut surgeons and gastroenterologists in the United States. METHODS: We created a survey of postoperative PPI management protocols, with an emphasis on discontinuation and timing of PPI cessation, and aimed to determine what factors played a role in the decision-making. An electronic survey tool (Qualtrics XM, Qualtrics, Provo, UT) was used to distribute the survey and to record the responses anonymously for a period of three months. RESULTS: The survey was viewed 2658 times by 373 institutions and shared with 644 members. In total, 121 respondents participated in the survey and 111 were surgeons (92%). Fifty respondents (42%) always discontinue PPIs immediately after ARS. Of the remaining 70 respondents (58%), 46% always wean or taper PPIs postoperatively and 47% wean or taper them selectively. The majority (92%) of practitioners taper within a 3-month period postoperatively. Five respondents never discontinue PPIs after ARS. Overall, only 23 respondents (19%) stated their protocol is based on medical literature or evidence-based medicine. Instead, decision-making is primarily based on anecdotal evidence/personal preference (42%, n = 50) or prior training/mentors (39%, n = 47). CONCLUSIONS: There are two major protocols used for PPI discontinuation after ARS: Nearly half of providers abruptly stop PPIs, while just over half gradually tapers them, most often in the early postoperative period. These decisions are primarily driven by institutional practices and personal preferences, underscoring the need for evidence-based recommendations.

Does Implant Placement Below the Ridge Reduce Crestal Bone Loss? A Split-Mouth Randomized Controlled Clinical Trial.

Reducing crestal bone loss (CBL) around implants allows for soft tissue stability and long-term success. The aim of the present study was to evaluate the extent of CBL in implants placed with the implant shoulder at the equi-crestal level and 2 mm below the alveolar ridge at 2, 12, 36, and 60 months. A split-mouth randomized controlled clinical trial was conducted by selecting subjects with Kennedy Class IV partial edentulism of the lower jaw. Two implants were inserted, of equal length and diameter, one equi-crestal and the other sub-crestal, in the site corresponding to the lateral incisor. Intraoral periapical radiographs with Rinn centering devices were performed at the time of implant insertion (T0), at 2 (T1), 12 (T2), 36 (T3), and 60 months (T4). Descriptive statistics and the T-test were used, setting the significance to P⩽ 0.05. Twenty-five subjects were recruited, with a mean age of 65 years (SD 9.88, range 42-82). No subject dropped out. A total of 50 implants were inserted, 25 at crestal and 25 sub-crest level. At the 60-month follow-up, no implant or prosthetic failure was recorded. An average loss of -0.81 mm was recorded in the crestal implant group (n.25; SD: 0.40; max-min: -1.6 - -0.1) while in the implants positioned below the crest the average CBL was -0.87mm (n.25; SD: 0.41; max-min: -2 - -0.2); however, the higher CBL in the sub-crestal implant group was not statistically significant (P=0.65). Comparing the mean CBL values of the two groups at the various follow-ups, a greater crestal bone resorption was recorded in sub-crest implants between T0 and T1 (-0.25 vs -0.1) and between T1 and T2 (-0.39 vs -0.23), while in subsequent follow-ups a greater, statistically significant (P=0.01), crestal bone loss was recorded in ridge implants between T3 and T4 (-0.05 vs -0.18). Over time, therefore, the extent of CBL seems to be reduced in implants placed below the crest, with bone retention above the implant shoulder. Ultimately, although the position of the implant shoulder relative to the crestal ridge doesn't affect the CBL, sub-crestal placement is recommended in order to reduce the risk of exposure of the rough surface of the implant.

Buprenorphine Facilitates Rapid Weaning From Very-High-Dose Intrathecal Hydromorphone.

Pain management in patients on chronic opioid therapy is a common clinical challenge. The phenomena of opioid-induced hyperalgesia and tolerance are important contributors to that challenge. There are multiple strategies described to wean opioid doses and/or transition patients off opioids altogether. However, there is very little data to guide transitions off chronic intrathecal opioids. Here, we report on two patients with intractable post-laminectomy pain syndrome, resulting in severe functional limitation in the setting of opioid escalation culminating in the intrathecal delivery of hydromorphone to daily doses as high as 20 mg/day. We describe their rapid successful weaning off opioids using low-dose buprenorphine, which resulted in a dramatic improvement in pain and function.

Long stem revision versus short stem revision with plate osteosynthesis for Vancouver type B2 periprosthetic femoral fracture: a comparative study of eighty five cases.

PURPOSE: Periprosthetic femoral fractures (PPFs) around the hip are challenging complications in orthopaedic surgery, particularly Vancouver type B2 (VTB2) fractures. The surgical management of these fractures is crucial and depends on various factors. Cementless short taper stem with plate osteosynthesis is an alternative surgical technique. This study aims to compare the outcomes of this surgical technique with revision arthroplasty (RA) with long stem in the treatment of VTB2 PPFs. METHODS: This retrospective study was conducted in a single medical institute from February 2010 to May 2019. Patients who had received either total hip arthroplasty or bipolar hemiarthroplasty and subsequently developed a VTB2 PPF were included; patients who sustained intra-operative fractures or received a cemented stem previously were excluded from the analysis. The patients were divided into two groups: group I received RA with cementless long stem, while group II underwent RA with cementless short taper stem with plate osteosynthesis. Demographic data, radiographic and functional outcomes, and complications were analyzed between the two groups. RESULTS: A total of 85 patients diagnosed with VTB2 PPFs were included in the study. There were no significant differences between the two groups in terms of demographic data, including age, gender, mean follow-up times, estimated blood loss, and operative times. The radiographic results showed that there was no significant difference in the incidence of subsidence and implant stability between the two groups. However, group II tended to have less subsidence and periprosthetic osteolysis. Patients in group II had significantly better functional scores (mean Harris hip score: post-operative: 60.2 in group I and 66.7 in group ii; last follow-up: 77.4 in group 1 and 83.2 in group II (both p < 0.05)). There were no significant differences in the overall complication rate, including infection, dislocation, re-fracture, and revision surgery, between the two groups. CONCLUSIONS: Both surgical techniques, cementless long stem and cementless short taper stem with plate osteosynthesis, are effective in the treatment of Vancouver B2 PPFs, with no significant differences in outcomes or complications. However, patients in cementless short taper stem with plate osteosynthesis had better functional scores at both post-operative and the last follow-up.

The influence of surgical technique guidance and surgeon's experience on the femoral head assembly in total hip arthroplasty.

INTRODUCTION: The importance of the assembly procedure on the taper connection strength is evident. However, existent surgical technique guides frequently lack comprehensive and precise instructions in this regard. The aim of our experimental study was to evaluate the influence of the surgical technique guide on the femoral head assembly procedure in surgeons with differing levels of experience in total hip arthroplasty. MATERIALS AND METHODS: Twenty-eight participants, divided into four groups based on their lifetime experience in total hip arthroplasty, conducted a femoral head assembly procedure in a simulated intraoperative environment before and after reviewing the surgical technique guide. Demographic information and the number of hammer blows were documented. Hammer velocity and impaction angle were recorded using an optical motion capturing system, while the impaction force was measured using a dynamic force sensor within the impactor. RESULTS: We observed a high variation in the number of hammer blows, maximum force, and impaction angle. Overall, the number of hammer blows decreased significantly from 3 to 2.2 after reviewing the surgical technique guide. The only significant intragroup difference in the number of hammer blows was observed in the group with no prior experience in total hip arthroplasty. No correlation was found between individual factors (age, weight, height) or experience and the measured parameters (velocity, maximum force and angle). CONCLUSIONS: The present study demonstrated a high variation in the parameters of the femoral head assembly procedure. Consideration of the surgical technique guide was found to be a limited factor among participants with varying levels of experience in total hip arthroplasty. These findings underline the importance of sufficient preoperative training, to standardize the assembly procedure, including impaction force, angle, and use of instruments.

Microgrooves with Small Taper Angle Processed by Nanosecond Laser in Closed Flowing Water.

To improve the capability of nanosecond lasers to process structures with a high aspect ratio, a new method of nanosecond laser processing in closed flowing water was proposed in this paper. The microgrooves on a stainless steel 304 surface were processed by the new method, and the influence of processing parameters on the microgrooves was studied. The comparative experiments of laser processing in still water and overflowing water were also carried out, and the unusual phenomenon of laser processing in different flowing water was discovered by a high-speed camera. The results showed that the flowing velocity played a crucial role in underwater laser processing, and that high flowing velocity could timely remove bubbles in closed flowing water, thus obtaining higher processing efficiency. As the depth of the groove increased, the bubbles firstly affected the processing of the sidewall, causing a circular transition between the sidewall and bottom surface. The reflection of the laser beam by the bubble could cause secondary processing on the sidewall, resulting in a decrease in the taper angle. Based on the above research, the microgroove with a width of 0.5 mm, aspect ratio of 3, and taper angle of 87.57° was successfully processed by a nanosecond laser in closed flowing water. Compared to conventional nanosecond laser processing, laser processing in closed flowing water was more advantageous in processing microgrooves with a small taper angle and high aspect ratio.

Clinical Performance of 170 Frictional Morse Taper Implants: 2 Years Follow-Up.

This study evaluated the clinical survival rates of 170 Morse taper implants through clinical and mechanical parameters in different therapeutic approaches such as single crowns, fixed partial prostheses, and fixed full-arch prostheses. Patients referred to the Center on Education and Research on Dental Implants from May 2017 to July 2018 with the indication for dental implant therapy, aged >18 years, without periodontal disease, recent evidence of inflammatory activity or other oral disorders, current pregnancy, uncontrolled diabetes mellitus or heavy smoking habit were included in this study. After 12 weeks of healing since the implants were placed in the mandible and after 16 weeks following implants placed in the maxilla, patients returned to the Center for prosthetic rehabilitation. After implant therapy, all patients underwent periodical, clinical, and prosthetic examinations every 6 months. Prosthetic restorations involved 109 fixed reconstructions in function. Few prosthetic complications were reported (6.55%). Twenty implants were rehabilitated with cemented prostheses; from those, 1 crown suffered a loss in retention/decementation. Of the 148 implants rehabilitated with screwed-retained prostheses, 6.76% suffered prosthetic screw loosening. The cumulative implant survival rate was 98.2%. When peri-implant tissue health was evaluated, the keratinized mucosa band appeared related to peri-implant tissue stability. Thus, Morse taper implants represented a successful procedure for implant rehabilitation, with a high cumulative implant survival rate, low prevalence of biological and prosthetic complications, and good stability of peri-implant tissues over the assessed period.

The Effects of Etchant on via Hole Taper Angle and Selectivity in Selective Laser Etching.

This research focuses on the manufacturing of a glass interposer that has gone through glass via (TGV) connection holes. Glass has unique properties that make it suitable for 3D integrated circuit (IC) interposers, which include low permittivity, high transparency, and adjustable thermal expansion coefficient. To date, various studies have suggested numerous techniques to generate holes in glass. In this study, we adopt the selective laser etching (SLE) technique. SLE consists of two processes: local modification via an ultrashort pulsed laser and chemical etching. In our previous study, we found that the process speed can be enhanced by changing the local modification method. For further enhancement in the process speed, in this study, we focus on the chemical etching process. In particular, we try to find a proper etchant for TGV formation. Here, four different etchants (HF, KOH, NaOH, and NH4F) are compared in order to improve the etching speed. For a quantitative comparison, we adopt the concept of selectivity. The results show that NH4F has the highest selectivity; therefore, we can tentatively claim that it is a promising candidate etchant for generating TGV. In addition, we also observe a taper angle variation according to the etchant used. The results show that the taper angle of the hole is dependent on the concentration of the etchant as well as the etchant itself. These results may be applicable to various industrial fields that aim to adjust the taper angle of holes.

Effect of the pre-taper level of fatigue on the taper-induced changes in performance in elite swimmers.

Introduction: In swimming, performance gains after tapering could be influenced by the pre-taper level of fatigue. Moreover, this level of fatigue could be associated with sleep. This study aimed to assess (1) the effect of tapering on performance according to the pre-taper level of fatigue in swimmers and (2) the association between sleep and pre-taper level of fatigue. Methods: Physiological, psychological and biomechanical profiles were evaluated in 26 elite swimmers on 2 occasions to estimate the pre-taper level of fatigue: at T0 and T1, scheduled respectively 10 and 3 weeks before the main competition. Sleep quantity and quality were also evaluated at T0 and T1. Race time was officially assessed at T0, T1 and during the main competition. The level of significance was set at p ≤ .05. Results: Fourteen swimmers (17 ± 2 years) were allocated to acute fatigue group (AF) and 12 swimmers (18 ± 2 years) to functional overreaching group (F-OR). From T1 to the main competition, performance was improved in AF (+1.80 ± 1.36%), while it was impaired in F-OR (-0.49 ± 1.58%, p < 0.05 vs. AF). Before taper period, total sleep time was lower in F-OR, as compared to AF. Conversely, the fragmentation index was higher in F-OR (p = .06). From wakefulness to sleep, body core temperature decreased in AF but not in F-OR. Discussion: Performance gain after tapering was higher in AF swimmers than in overreached. Moreover, pre-taper sleep was poorer in overreached swimmers, which could contribute to their different response to the same training load. This poorer sleep could be linked to a lower regulation of internal temperature.

Novel Use of Clonidine Patch to Treat Tizanidine Withdrawal.

Tizanidine is commonly prescribed for muscle spasticity and pain. Yet, withdrawal is rarely reported. Tizanidine stimulates presynaptic α-2 adrenergic and imidazoline receptors decreasing norepinephrine release. Abrupt cessation can cause withdrawal. Current treatment strategies include tapering oral tizanidine or substituting oral clonidine. A 52-year-old male with a history of hypertension, diabetes, coronary artery disease, and chronic back pain presented with altered mental status, agitation, hypertensive emergency (blood pressure: 250/145 mmHg), and tachycardia. The patient had been prescribed tizanidine for chronic back pain for two years and had recently run out with suspicion of misuse. Tizanidine withdrawal was diagnosed, and he improved with 0.1 mg oral clonidine three times daily weaned over five days while hospitalized. One month later the patient was admitted for persistent hypertension, tachycardia, diaphoresis, and anxiety. Alpha-2 agonist withdrawal was again diagnosed. Utilizing a clonidine patch taper may offer a reasonable approach in patients with tizanidine withdrawal.

Experimental periprosthetic fractures with collarless polished tapered cemented stems.

PURPOSE: After cemented total hip arthroplasty, the risk of periprosthetic fracture (PPF) of taper-slip stems is higher than that of composite-beam stems. We aimed to assess the conditions resulting in PPFs of taper-slip stems using a falling weight. METHODS: Taper-slip stems were fixed to five types of simulated bone models using bone cement, and the fractures were evaluated by dropping stainless-steel weights from a predetermined height onto the heads. The periprosthetic fracture height in 50% of the bone models (PPFH50) was calculated using the staircase method. RESULTS: For the fixation with 0° of flexion, the values for PPFH50 were 61 ± 11, 60 ± 13, above 110, 108 ± 49, and 78 ± 12 cm for the cobalt-chromium-molybdenum alloy, stainless steel alloy (SUS), titanium alloy (Ti), smooth surface, and thick cement mantle models, respectively; for the fixation with 10° of flexion (considering flexure), the PPFH50 values were 77 ± 5, 85 ± 9, 90 ± 2, 89 ± 5, and 81 ± 11 cm, respectively. The fracture rates of the polished-surface stems were 78.6 and 35.7% at the proximal and distal sites, respectively (p < 0.05); the fracture rates of the smooth-surface stems were 14.2 and 100%, respectively (p < 0.05). CONCLUSION: The impact tests demonstrated that the conditions that were less likely to cause PPFs were use of Ti, a smooth surface, a thick cement mantle, and probably, use of SUS.

Influence of rotor impeller structure on performance improvement of suspended axial flow blood pumps.

BACKGROUND: The hydrodynamic suspension structure design of the axial blood pump impeller can avoid the problems associated with using mechanical bearings. However, the particular impeller structure will impact the hydraulic performance and hemolysis of the blood pump. METHOD: This article combines computational fluid dynamics (CFD) with the Lagrange particle tracking method, aiming to improve the blood pump's hydraulic and hemolysis performance. It analyzes the flow characteristics and hemolysis performance inside the pump. It optimizes the taper of the impeller hub, the number of blades, and the inclination angle of the circumferential groove at the top of the blade. RESULTS: Under certain rotational speed conditions, an increase in the taper of the impeller hub or the number of blades can increase the pumping pressure of a blood pump, but an increase in the number of blades will reduce the flow rate. The design of circumferential grooves at the top of the blade can increase the pumping pressure to a certain extent, with little impact on the hemolysis performance. The impeller structure is optimized based on the estimated hemolysis of each impeller model blood pump. It could be seen that when the pump blood pressure and flow rate were reached, the optimized impeller speed was reduced by 11.4%, and the estimated hemolysis value was reduced by 10.5%. CONCLUSION: In this paper, the rotor impeller structure of the blood pump was optimized to improve the hydraulic and hemolytic performance effectively, which can provide a reference for the related research of the axial flow blood pump using hydraulic suspension.

Patient Perspectives on Mental Health and Pain Management Support Needed Versus Received During Opioid Deprescribing.

Prescription opioid tapering has increased significantly over the last decade. Evidence suggests that tapering too quickly or without appropriate support may unintentionally harm patients. The aim of this analysis was to understand patients' experiences with opioid tapering, including support received or not received for pain control or mental health. Patients with evidence of opioid tapering from 6 health care systems participated in semi-structured, in-depth interviews; family members of suicide decedents with evidence of opioid tapering were also interviewed. Interviews were analyzed using thematic analysis. Participants included 176 patients and 16 family members. Results showed that 24% of the participants felt their clinicians checked in with them about their taper experiences while 41% reported their clinicians did not. A majority (68%) of individuals who experienced suicide behavior during tapering reported that clinicians did check in about mood and mental health changes specifically; however, 27% of that group reported no such check-in. More individuals reported negative experiences (than positive) with pain management clinics-where patients are often referred for tapering and pain management support. Patients reporting successful tapering experiences named shared decision-making and ability to adjust taper speed or pause tapering as helpful components of care. Fifty-six percent of patients reported needing more support during tapering, including more empathy and compassion (48%) and an individualized approach to tapering (41%). Patient-centered approaches to tapering include reaching out to monitor how patients are doing, involving patients in decision-making, supporting mental health changes, and allowing for flexibility in the tapering pace. PERSPECTIVE: Patients tapering prescription opioids desire more provider-initiated communication including checking in about pain, setting expectations for withdrawal and mental health-related changes, and providing support for mental health. Patients preferred opportunities to share decisions about taper speed and to have flexibility with pausing the taper as needed.

New Ceramic Heads With Titanium Sleeves on Retained Femoral Components: Results of Over 500 Revision Total Hip Arthroplasties.

BACKGROUND: Ceramic heads are frequently combined with titanium sleeves in revision total hip arthroplasties (THAs), ostensibly to protect the ceramic head from existing damage to the retained trunnion. Although widely adopted, data on the performance and safety of this construct are minimal. The purpose of this study was to describe implant survivorships, radiographic results, and clinical outcomes of patients who underwent revision THA with a ceramic head and titanium sleeve on a retained femoral component. METHODS: We identified 516 revision THAs with femoral component retention (328 acetabular-only revisions and 188 bearing surface exchanges) treated with a new ceramic head and titanium sleeve between 2000 and 2020. Mean age at revision was 64 years, 56% were women, and mean body mass index was 30. The indications for revision THA were adverse local tissue reaction (25%), acetabular loosening (24%), dislocation (17%), infection (5%), and other (29%). Kaplan-Meier survivorships were analyzed, radiographs reviewed, and Harris Hip Scores evaluated. Mean follow-up was 4 years (range, 2 to 10). RESULTS: There were no reoperations or failures for ceramic head fracture, taper corrosion, or head/sleeve disengagement. The 10-year survivorship free of any re-revision was 85%. Indications for the 57 re-revisions included dislocation (33), infection (13), acetabular component loosening (7), periprosthetic fracture (2), psoas impingement (1), and sciatic nerve irritation (1). The 10-year survivorship free of any reoperation was 82%. There were an additional 14 reoperations. Radiographically, 1.9% had progressive femoral radiolucent lines, and 4.7% had progressive acetabular radiolucent lines. Mean Harris Hip Score was 81 at 2 years. CONCLUSIONS: New ceramic heads with titanium sleeves in revision THAs with retained femoral components were durable and reliable with no cases of ceramic head fracture or taper complications at mean 4-year follow-up, including those revised for adverse local tissue reaction. LEVEL OF EVIDENCE: IV.