Reporting Bias in the Form of Positive Spin Is Highly Prevalent in Abstracts of Systematic Reviews on Primary Repair of the Anterior Cruciate Ligament.

PURPOSE: To analyze reporting bias in the form of spin present in systematic reviews and meta-analyses on the topic of primary anterior cruciate ligament (ACL) repair. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed throughout this study. Peer-reviewed systematic reviews were collected from 3 databases (PubMed, Scopus, and SPORTDiscus), and their abstracts were assessed for the 15 most common types of spin. Articles were excluded if they were not published in English, had no evidence, were retracted, were published without an abstract, did not have full text available, or included cadaveric or nonhuman subjects. Full text quality was assessed using AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews Version 2). Fisher exact tests were used to examine associations between the different types of spin and other study characteristics such as AMSTAR 2 confidence rating, study design, and level of evidence. RESULTS: Spin was present in the abstracts of 13 of 15 articles (86.7%). There were significant associations between PRISMA adherence and lower incidences of spin types 3, 6, and 8 (P = .029 for each). A critically low AMSTAR 2 confidence rating was significantly associated with an increased incidence of spin type 9 (P = .01), and a higher AMSTAR 2 score was significantly associated with decreased spin type 4 and type 5 (P = .039 and P = .048, respectively). A more recent year of publication was correlated with a lower incidence of spin type 14 (P = .044). CONCLUSIONS: Spin is present in most systematic reviews and meta-analyses regarding primary repair of the ACL, with two-thirds of abstracts spinning evidence in favor of ACL repair. Standardized guidelines including the PRISMA guidelines and the AMSTAR 2 assessment tool were negatively correlated with spin. More recently published articles were found to contain significantly less spin, as were articles published in journals with higher Clarivate Impact Factors and Scopus CiteScores. LEVEL OF EVIDENCE: Level V, systematic review of Level III through V studies.

Harms reporting in randomized controlled trials underpinning the American Academy of Orthopaedic Surgeons clinical practice guidelines for glenohumeral osteoarthritis.

BACKGROUND: Glenohumeral osteoarthritis is one of the most common causes of shoulder pain. As such, the American Academy of Orthopaedic Surgeons (AAOS) has developed clinical practice guidelines (CPGs) to address the management of glenohumeral osteoarthritis. These CPG recommendations stem from the findings of randomized controlled trials (RCTs), which have been shown to influence clinical decision making and health policy. Therefore, it is essential that trial outcomes, including harms data (ie, adverse events), are adequately reported. We intend to evaluate the reporting quality of harms-related data in orthopedic literature specifically relating to AAOS CPG recommendations on the management of glenohumeral osteoarthritis. METHODS: We adhered to the Preferred Reporting Items for Systematic Reviews (PRISMA) as well as guidance for reporting meta-research. The AAOS CPGs for glenohumeral osteoarthritis were obtained from orthoguidelines.org, and 2 authors independently screened the guidelines for the RCTs referenced. A total of 14 studies were identified. Data were extracted from the 14 included studies independently by the same 2 authors. Adherence to the Consolidated Standards of Reporting Trials (CONSORT) Extension for Harms Checklist was assessed using an 18-item scoring chart, with 1 point being awarded for meeting a checklist item and 0 points being awarded for not meeting a checklist item. Descriptive statistics, such as frequencies, percentages, and 95% confidence intervals were used to summarize RCT adherence to the CONSORT checklist. RESULTS: The average score among the studies included was 7.36/18 items (39% adherence). No study adhered to all criteria, with the highest-performing study meeting 11 of 18 items (58%) and the lowest meeting 3 of 18 items (16%). A positive correlation between checklist score and year of publication was observed, with studies published more recently receiving a higher score on the CONSORT checklist (P < .05). Studies that disclosed funding information received a higher score than those that did not (P < .05), but there was no significant difference when the different funding sources were compared. Finally, double-blinded studies scored higher on the checklist than those with lower levels of blinding (single or no blinding, P < .05). CONCLUSION: Adverse events are poorly reported amongst RCTs cited as supporting evidence for AAOS Management of Glenohumeral Osteoarthritis CPGs, evidenced by a CONSORT checklist compliance rate of only 41% in this study. We recommend the development of an updated checklist with information that makes it easier for authors to recognize, evaluate, and report on harms data. Additionally, we encourage authors to include information about adverse events or negative outcomes in the abstract.

Evaluation of spin in systematic reviews on the use of tendon transfer for massive irreparable rotator cuff tears.

PURPOSE: To identify, describe and account for the incidence of spin in systematic reviews and meta-analyses of tendon transfer for the treatment of massive, irreparable rotator cuff tears. The secondary objective was to characterize the studies in which spin was identified and to determine whether identifiable patterns exist among studies with spin. METHODS: This study was conducted per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Each abstract was assessed for the presence of the 15 most common types of spin derived from a previously established methodology. General data that were extracted included study title, authors, publication year, journal, level of evidence, study design, funding source, reported adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, preregistration of the study protocol, and methodologic quality per A Measurement Tool to Assess Systematic Reviews Version 2 (AMSTAR 2). RESULTS: The search yielded 53 articles, of which 13 were included in the final analysis. Articles were excluded if they were not published in a peer reviewed journal, not written in English, utilized cadaveric or nonhuman models, or lacked an abstract with accessible full text. 53.8% (7/13) of the included studies contained at least 1 type of spin in the abstract. Type 5 spin ("The conclusion claims beneficial effect of the experimental treatment despite a high risk of bias in primary studies") was the most common, appearing in 23.1% (3/13) of included abstracts. Nine of the spin categories did not appear in any of the included abstracts. A lower AMSTAR 2 score was significantly associated with the presence of spin in the abstract (P < .006). CONCLUSION: Spin is highly prevalent in the abstracts of systematic reviews and meta-analyses concerning tendon transfer for massive rotator cuff tears. A lower overall AMSTAR 2 rating was associated with a higher incidence of spin. Future studies should continue to explore the prevalence of spin in orthopedic literature and identify any factors that may contribute to its presence.

Effect of body mass index on complications following total shoulder arthroplasty: a population-wide analysis.

BACKGROUND: Evidence regarding the effect of body mass index (BMI) on complications following anatomic shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (rTSA) remains controversial. This high-powered study examines the effect of BMI on surgical and medical complications following aTSA and rTSA. METHODS: This retrospective cohort study was conducted using the Premier Healthcare Database to query all adult patients who underwent primary, elective TSA (aTSA, rTSA) from 2016 to 2020. Patients eligible for inclusion were identified using International Classification of Diseases -10 and CPT codes for primary TSA. Patients were stratified into 3 subgroups based on BMI (BMI <30 kg/m2, BMI 30-35 kg/m2, BMI >35 kg/m2). The primary endpoints assessed were 90-day risks of postoperative complications, revisions, and readmissions among the 3 BMI groups undergoing primary TSA. RESULTS: A total of 32,645 patients were analyzed; 10,951 patients underwent aTSA and 21,694 patients underwent rTSA. Patient populations for aTSA and rTSA differed significantly across all BMI categories in terms of age, sex, cost of care, and insurance status. After multivariate regression analysis, there was no increased risk of surgical complications in the aTSA and rTSA cohorts with BMI 30-35 kg/m2 and BMI >35 kg/m2. In the aTSA cohort, rates of acute respiratory failure (adjusted Odds Ratio [aOR] 2.65) was all significantly higher in the BMI >35 kg/m2 group. As for rTSA cohort, acute respiratory failure (aOR 1.67) and acute renal failure (aOR 1.53) were significantly higher in the BMI >35 kg/m2 group. CONCLUSION: While we found no increased risk of immediate postoperative surgical risks, patients with a BMI >35 kg/m2 demonstrated greater risk of medical complications after rTSA. Given this trend, providers should exercise caution in patient selection for TSA and counsel obese patients as to these increased risks. Future studies should aim to provide a more comprehensive picture of the effect of BMI on functional outcomes after TSA.

Recombinant factor VIII Fc fusion protein for immune tolerance induction in patients with severe haemophilia A with inhibitors-A retrospective analysis.

INTRODUCTION: Immune tolerance induction (ITI) is the gold standard for eradication of factor VIII inhibitors in severe haemophilia A; however, it usually requires treatment for extended periods with associated high burden on patients and healthcare resources. AIM: Review outcomes of ITI with recombinant factor VIII Fc fusion protein (rFVIIIFc) in patients with severe haemophilia A and high-titre inhibitors. METHODS: Multicentre retrospective chart review of severe haemophilia A patients treated with rFVIIIFc for ITI. RESULTS: Of 19 patients, 7 were first-time ITI and 12 were rescue ITI. Of 7 first-time patients, 6 had at least 1 high-risk feature for ITI failure. Four of 7 first-time patients were tolerized in a median of 7.8 months. The remaining 3 patients continue on rFVIIIFc ITI. Of 12 rescue patients, 7 initially achieved a negative Bethesda titre (≤0.6) in a median of 3.3 months, 1 had a decrease in Bethesda titre and continues on rFVIIIFc ITI and 4 have not demonstrated a decrease in Bethesda titre. Of these 4, 3 continue on rFVIIIFc ITI and 1 switched to bypass therapy alone. Two initially responsive patients transitioned to other factors due to recurrence. Overall, 16 of 19 patients remain on rFVIIIFc (prophylaxis or ITI). For those still undergoing ITI, longer follow-up is needed to determine final outcomes. No adverse events reported. CONCLUSIONS: Recombinant factor VIII Fc fusion protein demonstrated rapid time to tolerization in high-risk first-time ITI patients. For rescue ITI, rFVIIIFc showed therapeutic benefit in some patients who previously failed ITI with other products. These findings highlight the need to further evaluate the use of rFVIIIFc for ITI.

Effect of head lift exercise on kinematic motion of the hyolaryngeal complex and aspiration in patients with dysphagic stroke.

The head lift exercise (HLE) is a head-raising workout performed in a supine position. This exercise facilitates activation of the submental muscles located above the hyoid bone in front of the neck. HLE is a potential method to improve the movement of the hyolaryngeal movement and swallowing functions. The purpose of this study was to investigate the effect of HLE on the hyolaryngeal movement and aspiration in patients with dysphagic stroke. A total of 27 patients with stroke were randomly assigned either into the experimental (n = 13) or the control group (n = 14). The experimental group performed HLE 5 days a week for 4 weeks (a total of 20 sessions). Both groups received the same conventional dysphagia therapy. Two-dimensional analysis of the hyolaryngeal movement was carried out using Image J program based on a videofluoroscopic swallowing study. Penetration-aspiration was assessed using Penetration-Aspiration Scale (PAS). The experimental group showed a significant increase in the only superior movements of the hyoid bone compared with the control group (P = 0·033). Aspiration in liquid also exhibited a significant decrease in the experimental group compared with the control group (P = 0·044). Findings from this study confirmed that HLE is an effective intervention to improve hyoid movement and decrease aspiration.

Effects of neuromuscular electrical stimulation combined with effortful swallowing on post-stroke oropharyngeal dysphagia: a randomised controlled trial.

Neuromuscular electrical stimulation (NMES) has been used as a therapeutic intervention for dysphagia. However, the therapeutic effects of NMES lack supporting evidence. In recent years, NMES combined with traditional swallowing therapy has been used to improve functional recovery in patients with post-stroke dysphagia. This study aimed to investigate the effects of effortful swallowing combined with neuromuscular electrical stimulation on hyoid bone movement and swallowing function in stroke patients. Fifty stroke patients with mild dysphagia who were able to swallow against the resistance applied by using NMES and cooperate actively in training were included. This study was designed as a 6-week single-blind, randomised, controlled study. In the experimental group, two pairs of electrodes were placed horizontally in the infrahyoid region to depress the hyoid bone. The NMES intensity was increased gradually until the participants felt a grabbing sensation in their neck and performed an effortful swallow during the stimulation. In the placebo group, the same procedure was followed except for the intensity, which was increased gradually until the participants felt an electrical sensation. All participants underwent this intervention for 30 min per session, 5 sessions per week, for 6 weeks. Videofluoroscopic swallowing studies (VFSS) were carried out before and after the intervention and kinematics of the hyoid bone and swallowing function were analysed based on the VFSS. The experimental group revealed a significant increase in anterior and superior hyoid bone movement and the pharyngeal phase of the swallowing function. This intervention can be used as a novel remedial approach in dysphagic stroke patients.

Evaluation of Spin in Systematic Reviews and Meta-Analyses of Minimally Invasive Surgical Techniques and Standard Microdiscectomies for Treating Lumbar Disc Herniation.

STUDY DESIGN: Systematic review. OBJECTIVES: Spin in scientific literature is defined as bias that overstates efficacy and/or underestimates harms of procedures undergoing review. While lumbar microdiscectomies (MD) are considered the gold standard for treating lumbar disc herniations (LDH), outcomes of novel procedures are being weighed against open MD. This study identifies the quantity and type of spin in systematic reviews and meta-analyses of LDH interventions. METHODS: A search was conducted on the PubMed, Scopus, and SPORTDiscus databases for systematic reviews and meta-analyses evaluating the outcomes of MD against other LDH interventions. Each included study's abstract was assessed for the presence of the 15 most common types of spin, with full texts reviewed during cases of disagreement or for clarification. Full texts were used in the assessment of study quality per AMSTAR 2. RESULTS: All 34 included studies were observed to have at least 1 form of spin, in either the abstract or full text. The most common type of spin identified was type 5 ("The conclusion claims the beneficial effect of the experimental treatment despite a high risk of bias in primary studies"), which was observed in ten studies (10/34, 29.4%). There was a statistically significant association between studies not registered with PROSPERO and the failure to satisfy AMSTAR type 2 (P < .0001). CONCLUSION: Misleading reporting is the most common category of spin in literature related to LDH. Spin overwhelmingly tends to go in the positive direction, with results inappropriately favoring the efficacy or safety of an experimental intervention.

Evaluation of Spin in the Clinical Literature of Suture Tape Augmentation for Ankle Instability.

Background: Spin is defined as the use of specific reporting strategies to highlight the beneficial effect of a treatment despite nonsignificant results. The presence of spin in peer-reviewed literature can negatively impact clinical and research practices. The purpose of this study was to identify the quantity and types of spin present in primary studies and systematic reviews using suture tape augmentation for ankle instability as a model. Methods: This study was conducted per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Each abstract was assessed for the presence of the 15 most common types of spin. Extracted data included study title, authors, publication year, journal, level of evidence, study design, funding, reported adherence to PRISMA guidelines, and PROSPERO registration. Full texts of systematic reviews were used in the assessment of study quality per A Measurement Tool to Assess Systematic Reviews Version 2 (AMSTAR 2). Results: Nineteen studies were included in the final sample. At least 1 type of spin was identified in each study except one (18 of 19, 94.7%). The most common type of spin observed was type 3 ("selective reporting or overemphasis on efficacy outcomes or analysis favoring the beneficial effect of the experimental intervention") (6 of 19, 31.6%), The second most reported category of spin was type 4 ("the conclusion claims safety based on non-statistically significant results with a wide confidence interval") (4 of 19, 21.1%). Among systematic reviews, we identified type 5 ("the conclusion claims the beneficial effect of the experimental treatment despite a high risk of bias in primary studies") in 4 out of 6 (66.7%) of the articles that were included. No significant associations were found between study characteristics and type of spin. Conclusion: In this exploration of the introduction of a new technology, we identified spin to be highly present in the abstracts of primary studies and systematic reviews concerning suture tape augmentation for ankle instability. Steps should be taken by scientific journals to ensure that spin is minimized in the abstract to accurately reflect the quality of the intervention.

Volume, indications, and number of surgeons performing reverse total shoulder arthroplasty continue to expand: a nationwide cohort analysis from 2016-2020.

Background: Since its approval, reverse total shoulder arthroplasty (rTSA) has continued to increase in usage, with expanding indications beyond rotator cuff arthropathy. Existing literature has captured further increased utilization over the last decade through 2017. However, this data has not been updated to include a contemporary cohort of patients. This study sought to determine the trends of anatomic total shoulder arthroplasty (aTSA), rTSA, and hemiarthroplasty (HA) usage based on primary diagnosis and total number of surgeons performing each procedure annually from 2016-2020. Methods: Patients who underwent primary rTSA, aTSA, and HA from 2016-2020 were identified in the Premier Healthcare Database. Primary indication diagnoses for procedures were identified using International Classification of Diseases 10th edition codes. Temporal trends in patient and hospital demographics, primary indication, and procedure utilization were captured on an annualized basis. The number of surgeons performing each procedure annually was noted. Descriptive statistics were employed with significance set at P < .05. Results: From 2016 to 2020, 154,499 patients undergoing primary shoulder arthroplasty were identified: 48,890 aTSA, 95,808 rTSA, and 9801 HA. In 2016, rTSA comprised a slight majority (55%) of all arthroplasty cases but increased to nearly 70% of all arthroplasty cases in 2020. The absolute numbers of aTSA and HA cases decreased over time, while rTSA volume increased from 14,781 in 2016 to a high of 23,644 cases in 2019. There was a corresponding 12% increase in the number of surgeons performing rTSA across the same time period, contrasted with a 42.1% decrease in surgeons performing HA and a 14.3% decrease for aTSA. Glenohumeral osteoarthritis remains the most common indication for rTSA and aTSA, while HA is used primarily for proximal humerus fractures or hardware complications. Conclusion: The volume of primary rTSA in the United States has continued to increase from 2016 to 2020 with concurrent decreases in the number of primary aTSA and HA cases performed. Primary rTSA accounts for nearly 70% of all primary shoulder arthroplasty cases. The number of surgeons performing rTSA continues to increase, while there has been a decrease in the number of surgeons performing aTSA and HA.

Enzyme-mediated one-pot synthesis of hydrogel with the polyphenol cross-linker for skin regeneration.

Polyphenols can trigger immunity that activates intracellular anti-inflammatory signaling and prevents external infections. In this study, we report the fabrication of chitosan-based hydrogels with epigallocatechin gallate (EGCG) using enzyme-mediated one-pot synthesis. The tyrosinase-mediated oxidative reaction of the phenolic rings of EGCG with the primary amines on chitosan results in stable EGCG-chitosan hydrogels. The EGCG concentrations contributed to the cross-linking density and physical properties of EGCG-chitosan hydrogels. Furthermore, EGCG-chitosan hydrogels maintained intrinsic properties such as antibacterial and antioxidant effects. When endotoxin-activated RAW 264.7 macrophage cells were cultured with EGCG-chitosan hydrogels, the hydrogels reduced the inflammatory response of the RAW 264.7 cells. Furthermore, subcutaneous implantation of EGCG-chitosan hydrogels reduced endogenous macrophage and monocyte activation. When the EGCG-chitosan hydrogels were applied to a full-skin defect wound, they facilitated skin regeneration. Our study demonstrates that the one-pot synthesized EGCG-chitosan hydrogels can be applied in broad tissue regeneration applications that require immune modulation.

Development of squeeze flow in mechanical heart valve: a particle image velocimetry investigation.

Fluid between the reducing flow channel of the valve occluder and the orifice wall tends to be squeezed out of the flow channel, causing a high-speed flow. The squeeze flow is accompanied by a sharp local pressure drop, which may result in potential cavitation phenomenon in a mechanical heart valve (MHV). Limited experimental investigation has been conducted into the flow physics of this squeeze flow phenomenon, which is likely to be the origin of MHV cavitation. We used a pulsatile test loop simulating physiologic flow conditions and an actual-size transparent MHV model for flow visualization. A digital particle image velocimetry (DPIV) system incorporated with a microscope was applied to observe flow within a narrowing channel. A triggering mechanism was designed so that the DPIV system could be timed to capture images when the valve occluder was near its closing position. A series of images within the channel from 1.4 to 0.1 mm were captured. As the gap between the tip of the valve occluder and orifice wall becomes narrower, evidence of high-speed jet flow becomes more apparent. When the flow channel is reduced to around 0.1 mm, flow velocity of up to 2 m/s was noted. A sudden increase in high-speed jet flow causes a corresponding reduction in local pressure, and is a likely source for potential cavitation.

Measurement of cardiac output using Physio Flow with different positions of electrode placement.

INTRODUCTION: Physio Flow is a non-invasive impedance cardiograph device that measures cardiac output. Recommended electrode placements involve six electrodes, including two near the xiphisternum (Z3 and Z4/ ECG3/neutral). This study aims to evaluate if changing the positions of these two leads to the left fourth and fifth intercostal spaces along the mid-axillary line results in a change in the cardiac output measurement. METHODS: This was a prospective, controlled, crossover, paired study of 30 patients where electrodes were placed in the recommended positions and cardiac output (CO1) obtained after two minutes. The second cardiac output (CO2) was then obtained with the electrodes Z3 and Z4/ECG3/neutral repositioned at the left mid-axillary line at the fourth and fifth intercostal spaces. The final step involved switching the Z3 and Z4/ECG3/neutral leads back to the recommended position and the cardiac output (CO3) was measured. RESULTS: The average of the initial and third readings (COave) was compared with the measured CO2 and analysed. The regression equation was: CO at the proposed site (CO2) = COave at the recommended site + 0.058. The paired samples correlation was 0.995. Within the 95 percent limits of agreement, the bias with CO measured at the proposed site of electrode placement was 0.046 L/min with the limits at -0.24 L/min and 0.34 L/min. The mean difference was 0.86% of the average CO. CONCLUSION: A small positive bias was demonstrated when Physio Flow measurements were taken with the leads Z3 and Z4/ECG3/neutral placed in the mid-axillary line fourth and fifth intercostal spaces.

The role of follow-up endoscopy after total gastrectomy for gastric cancer.

BACKGROUND: Follow-up endoscopy after total gastrectomy for gastric cancer is commonly performed without there being any definite evidence of clinical relevance. Therefore, we investigated the role of the upper endoscopic examinations after total gastrectomy for gastric cancer. METHODS: The medical records of 212 early gastric cancer (EGC) patients and 622 advanced gastric cancer (AGC) patients who underwent follow-up endoscopic examination after total gastrectomy between 1994 and 2001 were reviewed. RESULTS: Two of 212 EGC patients and 233 of 622 AGC patients revealed tumour recurrence at all sites. All the endoscopically accessible local tumour recurrences (n=24) were found in the AGC group. Anastomosis site stenosis was detected in 72 of 834 patients. CONCLUSION: Follow-up endoscopy after total gastrectomy for gastric cancer is useful in detecting complications and tumour recurrence. However, this procedure has a limited role in the clinical management and overall survival for patients with recurrent gastric adenocarcinoma.

Segmental volume distensibility of the canine thoracic aorta in vivo.

Segments of the canine ascending aorta, upper descending thoracic aorta, and middle descending thoracic aorta were instrumented with ultrasonic dimension gauges and a cathetertip manometer simultaneously to measure changes in segment diameter, length, and intravascular pressure. Volume distensibility (EV) was calculated as the sum of circumferential extensibility (EC), longitudinal extensibility (EL), and high order extensibilities (EK) for each segment. The EC and EL were linear expressions that represented percentage volume changes per mmHg pulse pressure due to circumferential and longitudinal dimensional changes. The high order extensibilities (second and third order) accounted for the percentage volume changes per mmHg pulse pressure due to the interactions between circumferential and longitudinal dimensional changes. Mean(SEM) EV values from six dogs were 1.62(0.31), 0.84(0.08), and 0.62(0.08)% delta V/mmHg delta P for the ascending aorta, upper descending thoracic aorta, and middle descending thoracic aorta segments respectively. The EV, EL, and EK of the ascending aorta segment were significantly greater than those of the upper descending thoracic aorta and middle descending thoracic aorta segments, whereas EC was significantly less in the ascending aorta than in both the upper descending thoracic aorta and middle descending thoracic aorta segments. It is concluded that there are regional differences in aortic distensibility and its components in vivo. Longitudinal wall motion is an important determinant of these aortic mechanical properties.

One-year mortality in patients with bone and soft tissue sarcomas as an indicator of delay in presentation.

INTRODUCTION: For many cancers, one-year mortality following diagnosis is a reflection of either advanced stage at diagnosis, multiple co-morbidities and/or complications of treatment. One-year mortality has not been reported for soft tissue or bone sarcomas. This study reports 1-year sarcoma mortality data over a 25-year period, investigates prognostic factors and considers whether a delay in presentation affects 1-year mortality. METHODS: A total of 4,945 newly diagnosed bone sarcoma and soft tissue sarcoma patients were identified from a prospectively maintained, single institution oncology database. Of these, 595 (12%) died within 1 year of diagnosis. Both patient factors and tumour characteristics available at diagnosis were analysed for effect. RESULTS: There was significant variation in one-year mortality between different histological subtypes. There has been no significant change in mortality rate during the last 25 years (mean: 11.7%, standard deviation: 2.8 percentage points). Soft tissue sarcoma patients who survived over one year reported a longer duration of symptoms preceding diagnosis than those who died (median: 26 vs 20 weeks, p<0.001). Prognostic factors identified in both bone and soft tissue sarcomas mirrored those for mid to long-term survival, with high tumour stage, large tumour size, metastases at diagnosis and increasing age having the greatest predictive effect. CONCLUSIONS: One-year mortality in bone and soft tissue sarcoma patients is easy to measure, and could be a proxy for late presentation and therefore a potential performance indicator, similar to other cancers. It is possible to predict the risk of one-year mortality using factors available at diagnosis. Death within one year does not correlate with a long history but is associated with advanced disease at diagnosis.

Generation of Charged Nanoparticles During Thermal Evaporation of Silver at Atmospheric Pressure.

The generation of charged silver nanoparticles in the gas phase during thermal evaporation of silver at atmospheric pressure was confirmed by the nano-differential mobility analyzer (DMA). Effects of the evaporation temperature, the nitrogen gas flow rate and the amount of silver to be evaporated on the size distribution of charged nanoparticles (CNPs) were examined. Both positively and negatively-charged nanoparticles were generated under all processing conditions adopted in this study. The deposition behavior of CNPs was affected by the gas flow, which is affected by the temperature gradient in the reactor and by the applied electric bias. The electric bias, which not only enhanced the film growth rate but also produced a much denser film surface, turned out to be an important process parameter under the condition where an appreciable amount of CNPs is generated.

Dynamic analysis of flutter in disk type mechanical heart valve prostheses.

Parametric study of the low frequency oscillations occasionally observed in certain types of disc type prosthetic heart valves (PHV) are carried out using a finite element technique. The analysis is performed to determine the frequencies of the dynamic fluttering with the help of the 'ANSYS' computer program. The results show that the frequencies of the dynamic fluttering for both the circular occluders and the semi-circular occluders are at least two orders of magnitude higher than that observed in vivo. It is thus concluded that the clinically observed leaflet oscillations should not be a dynamic flutter phenomenon. Rather, the vortex shedding has been assumed to be the cause of these oscillations.

A squeeze flow phenomenon at the closing of a bileaflet mechanical heart valve prosthesis.

In vivo cavitation in cardiovascular flow fields may occur under very unusual circumstances as a localized transient phenomenon which are confined to very small regions in the vicinity of the valve body or leaflet surface. The violent collapse of cavitation bubbles induces local erosion that may lead to structural damage. The fluid mechanical factors that may cause in vivo cavitation inception in mechanical heart valve (MHV) prostheses are investigated. It is established that the closing velocity of the leaflet holds the key to MHV cavitation. During the final phase of valve closing, the fluid mass in the gap space between the closing occluder and the valve's body is squeezed into motion by the rapidly approaching boundaries. The flow pattern created by this motion (termed 'squeeze flow'), is found to be related to the valve geometry, and the impact velocity of the closing leaflet. Given the closing velocity of the leaflet and the geometry of the MHV, computational flow dynamics (CFD) are made to determine the velocity distributions in the gap flow field of a bileaflet MHV in the mitral position. A two dimensional, time dependent model of the gap space show that flow velocity in the gap space can reach values as high as 30 ms-1 in regions near the edge of the inflow surface of the Edwards Duromedics (ED) MHV leaflet. This high speed stream ejected from the gap channel can create the conditions that characterize cavitation. The location of the isolated high speed region corresponds to the surface erosion that was observed in a number of damaged ED-MHV explants.