A novel class of xylanases specifically degrade marine red algal ß1,3/1,4-mixed-linkage xylan.

Xylans are polysaccharides composed of xylose and include ß1,4-xylan, ß1,3-xylan, and ß1,3/1,4-mixed-linkage xylan (MLX). MLX is widely present in marine red algae and constitutes a significant organic carbon in the ocean. Xylanases are hydrolase enzymes that play an important role in xylan degradation. While a variety of ß1,4-xylanases and ß1,3-xylanases involved in the degradation of ß1,4-xylan and ß1,3-xylan have been reported, no specific enzyme has yet been identified that degrades MLX. Herein, we report the characterization of a new MLX-specific xylanase from the marine bacterium Polaribacter sp. Q13 which utilizes MLX for growth. The bacterium secretes xylanases to degrade MLX, among which is Xyn26A, an MLX-specific xylanase that shows low sequence similarities (<27%) to ß1,3-xylanases in the glycoside hydrolase family 26 (GH26). We show that Xyn26A attacks MLX precisely at ß1,4-linkages, following a ß1,3-linkage toward the reducing end. We confirm that Xyn26A and its homologs have the same specificity and mode of action on MLX, and thus represent a new xylanase group which we term as MLXases. We further solved the structure of a representative MLXase, AlXyn26A. Structural and biochemical analyses revealed that the specificity of MLXases depends critically on a precisely positioned ß1,3-linkage at the -2/-1 subsite. Compared to the GH26 ß1,3-xylanases, we found MLXases have evolved a tunnel-shaped cavity that is fine-tuned to specifically recognize and hydrolyze MLX. Overall, this study offers a foremost insight into MLXases, shedding light on the biochemical mechanism of bacterial degradation of MLX.

The catabolic specialization of the marine bacterium Polaribacter sp. Q13 to red algal ß1,3/1,4-mixed-linkage xylan.

Catabolism of algal polysaccharides by marine bacteria is a significant process of marine carbon cycling. ß1,3/1,4-Mixed-linkage xylan (MLX) is a class of xylan in the ocean, widely present in the cell walls of red algae. However, the catabolic mechanism of MLX by marine bacteria remains elusive. Recently, we found that a marine Bacteroidetes strain, Polaribacter sp. Q13, is a specialist in degrading MLX, which secretes a novel MLX-specific xylanase. Here, the catabolic specialization of strain Q13 to MLX was studied by multiomics and biochemical analyses. Strain Q13 catabolizes MLX with a canonical starch utilization system (Sus), which is encoded by a single xylan utilization locus, XUL-Q13. In this system, the cell surface glycan-binding protein SGBP-B captures MLX specifically, contributing to the catabolic specificity. The xylanolytic enzyme system of strain Q13 is unique, and the enzymatic cascade dedicates the stepwise hydrolysis of the ß1,3- and ß1,4-linkages in MLX in the extracellular, periplasmic, and cytoplasmic spaces. Bioinformatics analysis and growth observation suggest that other marine Bacteroidetes strains harboring homologous MLX utilization loci also preferentially utilize MLX. These results reveal the catabolic specialization of MLX degradation by marine Bacteroidetes, leading to a better understanding of the degradation and recycling of MLX driven by marine bacteria.IMPORTANCERed algae contribute substantially to the primary production in marine ecosystems. The catabolism of red algal polysaccharides by marine bacteria is important for marine carbon cycling. Mixed-linkage ß1,3/1,4-xylan (MLX, distinct from hetero-ß1,4-xylans from terrestrial plants) is an abundant red algal polysaccharide, whose mechanism of catabolism by marine bacteria, however, remains largely unknown. This study reveals the catabolism of MLX by marine Bacteroidetes, promoting our understanding of the degradation and utilization of algal polysaccharides by marine bacteria. This study also sets a foundation for the biomass conversion of MLX.

Iridium-phosphine ligand complexes as an alternative to rhodium-based catalysts for the efficient hydroformylation of propene.

Expensive rhodium (Rh)-based catalysts have been widely used for the hydroformylation of propene. To find a cheaper and effective alternative to these Rh-based catalysts, herein, a series of phosphine ligands were used to coordinate with iridium, and their catalytic reactivities for the hydroformylation of propene were systematically investigated in this study. The effects of different phosphine ligands, pressures, temperatures, and catalyst dosages on the hydroformylation of propene were investigated. Tripyridyl phosphine iridium Ir2(cod)2Cl2-P(3-py)3 (Ir(I)-L5) and its derivatives exhibit the highest catalytic reactivity. Surprisingly, the catalytic reactivity of Ir(I)-L5 is higher than that of Rh2(cod)2Cl2-P(3-py)3 (Rh(I)-L5). When the Ir(I)-L5 complex is used as the catalyst, reactions performed in a polar solvent gave higher turnover number (TON) values than those in a non-polar solvent. Up to a TON of 503 can be obtained. Different n-butyraldehyde/iso-butyraldehyde (n/i) ratios can be obtained by adjusting the phosphine ligands or the proportion of gas pressure. The catalyst showed good reusability in five recycling experiments. Furthermore, based on DFT theoretical calculations, a probable reaction mechanism was proposed. It is reliable that an Ir-based catalyst can be considered as a highly effective catalyst for the hydroformylation of propylene with CO.

Clinical Outcome of Patients with Transposition of the Great Arteries and Intramural Coronary Artery.

To review the early and intermediate outcomes of patients with transposition of the great arteries (TGA) and intramural coronary artery (IMCA) who underwent arterial switch operation (ASO) at our center. Among 450 patients with TGA who underwent an ASO between 2010 and 2018, 26 (5.8%) patients were identified with IMCA. The left coronary artery was intramural in 21 of 26 patients. We adopted coronary transfer using double coronary buttons with unroofed intramural course for all 26 patients. Early mortality for patients with IMCA was 3 of 26 (11.5%) compared with 10 of 424 (2.4%) for those without IMCA (p = 0.007). Six patients suffered major adverse events, including extracorporeal membrane oxygenation support in 3 patients, delayed sternal closure in 6 patients. The follow-up was available for all 23 survivors, with the mean follow-up period of 73.5 ± 28.7 months. There was no late death and reinterventions, and all patients were asymptomatic at last follow-up. One patient exhibited moderate neopulmonary regurgitation, and 1 patient presented with distal stenosis of the right pulmonary artery. Coronary transfer using double coronary buttons with unroofed intramural course was a good option for patients with TGA and IMCA. With this technique, ASO could be performed with optimal early and intermediate outcomes.

Outcomes of the Warden Procedure for Partial Anomalous Pulmonary Venous Drainage.

Partial anomalous pulmonary venous drainage (PAPVD) is a common congenital heart disease. If the insertion of an anomalous pulmonary vein (PV) is high into the superior vena cava (SVC), the traditional 1-patch or 2-patch surgical repair might be challenging. Unlike patch procedures, the cavoatrial anastomosis technique (Warden procedure) theoretically reduces complications such as sinus node dysfunction and venous obstruction. We investigate outcomes of the Warden procedure (WP) at a single institution. A total of 67 patients (42 males and 25 females) with PAPVD who underwent the WP between January 2011 and December 2018 were consecutively enrolled. The median age was 2.8 years (3-61 years old). 52 cases were younger than 18 years old. perioperative and follow-up clinical data were collected. In addition, we selected possible risk factors (a total of 18 risk factors) of SVC stenosis or obstruction. Univariate and multivariate analyses were conducted to confirm the independent risk factors. The average Cardiopulmonary bypass (CPB) time was 132.3 ± 46.3 min, and the aortic cross-clamp time was 85.2 ± 35.7 min. One patient died postoperatively in hospital. The mean follow-up time of the remaining patients (n = 66) was 15.8 ± 14.5 months (3-64 months). No abnormal cardiac function or sinus node dysfunction cases were identified during the follow-up. Of the survival patients, no venous obstruction was presented before the discharge. Numbers of patients identified with mild PV and SVC stenosis were 1 (1.5%) and 7 (10.6%, 4 of them turned negative eventually) at discharge. At the last follow-up, no PV obstruction was identified, whereas, 4 cases (6%) had SVC obstruction. Numbers of PV and SVC stenosis cases were 3 (4.5%) and 8 (12%). Univariate and multivariate analyses showed that only the diameter of SVC less than 10 mm was an independent risk factor for SVC stenosis or obstruction at the last follow-up. Warden procedure can effectively treat PAPVD (anomalous drainages into SVC), with satisfactory early and mid-term postoperative results. Different modifications of the Warden procedure may be selected according to the anatomic characteristics. The diameter of SVC less than 10 mm predicts SVC stenosis or obstruction after Warden procedure.

Clinical application of a 3D-printed scaffold in chronic wound treatment: a case series.

OBJECTIVE: This case series evaluates the safety and effectiveness of 3D-printed scaffold in chronic wounds. The scaffold is a composite of natural and synthetic materials, and can be prepared in the form of powder or membrane. METHOD: We recruited patients with pressure ulcera (PU) and/or a diabetic foot ulcers (DFU). We used two methods: 3D-printed scaffolds alone, or 3D-printing powder mixed with platelet-rich fibrinogen (PRF). Clinicians and patients were asked to rate the scaffold's ease of application and comfort during use. RESULTS: A total of five patients were recruited; four with a PU and one with a DFU. For the patient treated with the 3D-printed scaffold membrane (n=1), their PU healed in 28 days, and for patients treated with the 3D-printed scaffold powder (n=2), their PUs healed in 54 days. For the patients treated with the 3D-printing powder mixed with PRF (n=2), the patient with a PU healed in 11 days, and the patient with the DFU healed in 14 days. All clinicians rated the 3D-printed scaffold as 'easy' or 'very easy' to use, and patients rated their comfort during wear and at dressing change as 'good' or 'very good'. CONCLUSION: This study demonstrated that 3D-printed scaffold was convenient to use, have the potential to improve wound healing rates, and provided a safe and effective way for treating chronic wounds.

A complexity evaluation system for mitral valve repair based on preoperative echocardiographic and machine learning.

BACKGROUND: To develop a novel complexity evaluation system for mitral valve repair based on preoperative echocardiographic data and multiple machine learning algorithms. METHODS: From March 2021 to March 2023, 231 consecutive patients underwent mitral valve repair. Clinical and echocardiographic data were included in the analysis. The end points included immediate mitral valve repair failure (mitral replacement secondary to mitral repair failure) and recurrence regurgitation (moderate or greater mitral regurgitation [MR] before discharge). Various machine learning algorithms were used to establish the complexity evaluation system. RESULTS: A total of 231 patients were included in this study; the median ejection fraction was 66% (63-70%), and 159 (68.8%) patients were men. Mitral repair was successful in 90.9% (210 of 231) of patients. The linear support vector classification model has the best prediction results in training and test cohorts and the variables of age, A2 lesions, leaflet height, MR grades, and so on were risk factors for failure of mitral valve repair. CONCLUSION: The linear support vector classification prediction model may allow the evaluation of the complexity of mitral valve repair. Age, A2 lesions, leaflet height, MR grades, and so on may be associated with mitral repair failure.

The FilZ Protein Contains a Single PilZ Domain and Facilitates the Swarming Motility of Pseudoalteromonas sp. SM9913.

Swarming regulation is complicated in flagellated bacteria, especially those possessing dual flagellar systems. It remains unclear whether and how the movement of the constitutive polar flagellum is regulated during swarming motility of these bacteria. Here, we report the downregulation of polar flagellar motility by the c-di-GMP effector FilZ in the marine sedimentary bacterium Pseudoalteromonas sp. SM9913. Strain SM9913 possesses two flagellar systems, and filZ is located in the lateral flagellar gene cluster. The function of FilZ is negatively controlled by intracellular c-di-GMP. Swarming in strain SM9913 consists of three periods. Deletion and overexpression of filZ revealed that, during the period when strain SM9913 expands quickly, FilZ facilitates swarming. In vitro pull-down and bacterial two-hybrid assays suggested that, in the absence of c-di-GMP, FilZ interacts with the CheW homolog A2230, which may be involved in the chemotactic signal transduction pathway to the polar flagellar motor protein FliMp, to interfere with polar flagellar motility. When bound to c-di-GMP, FilZ loses its ability to interact with A2230. Bioinformatic investigation indicated that filZ-like genes are present in many bacteria with dual flagellar systems. Our findings demonstrate a novel mode of regulation of bacterial swarming motility.

[Effect of unicompartmental knee arthroplasty in patients over 75 years old with knee osteoarthritis].

OBJECTIVE: To investigate the clinical effect of unicompartmental knee arthroplasty in patients with knee osteoarthritis over 75 years old. METHODS: From April 2010 to May 2015, 42 patients with knee medial compartment osteoarthritis were treated with Oxford third-generation unicompartmental knee arthroplasty. According to the single and bilateral replacement, the patients were divided into bilateral simultaneous replacement group and unilateral replacement group:11 patients in the simultaneous replacement group, 3 males and 8 females, aged (79.18±3.06) years;There were 31 cases in the unilateral replacement group, 13 males and 18 females, aged (78.16±3.48) years. The survival status of patients with knee prosthesis, the changes of hematocrit before and after operation, and the total amount of blood loss during and after operation were observed and compared;The HSS (Hospital for Special Surgery knee rating) scores of patients before and after operation were compared. RESULTS: There was significant difference in perioperative complications between two groups(P<0.05). All 42 patients were followed up for(5.7±2.3) years. One patient with a history of previous hypertension developed cerebral thrombosis in the 4th month after operation, one patient developed pad dislocation in the 4th month after operation, and two patients died of other medical diseases(1 myocardial infarction and 1 lung cancer) 3 years after operation. The total amount of postoperative blood loss in bilateral simultaneous replacement group was higher than that in unilateral replacement group(P<0.05);Four patients with bilateral simultaneous replacement received 2U blood transfusion after operation. The HSS score and total score of the two groups at 9 months after operation were higher than those before operation(P<0.05). CONCLUSION: Unicompartmental knee arthroplasty is a feasible surgical treatment for osteoarthritis patients over 75 years old with medial single compartment degeneration. For elderly patients over 75 years old with bilateral knee lesions, bilateral simultaneous unicompartmental knee arthroplasty is more traumatic than unilateral unicompartmental knee arthroplasty, which will increase the incidence of perioperative complications, affect the rapid postoperative recovery and increase the blood loss. Although the long-term effect is equivalent to that of unilateral unicompartmental knee arthroplasty, staged operation is still recommended to ensure the safety of operation.

Gilvimarinus xylanilyticus sp. nov., a novel 1,3-xylanase-secreting bacterium isolated from a marine green alga.

1,3-xylan, an important organic carbon in the ocean, is peculiar to marine algae. 1,3-xylanase-secreting bacteria and their extracellular 1,3-xylanases play pivotal roles in the degradation and biomass conversion of 1,3-xylan. However, only a few 1,3-xylanase-secreting bacteria and 1,3-xylanases have been reported. Here, we identified a novel marine bacterium capable of secreting 1,3-xylanases, designated as strain HB14T. Phylogenetic analysis revealed that strain HB14T clustered tightly with known species of the genus Gilvimarinus, showing the highest 16S rRNA gene sequence similarity (97.7%) with the type strain of Gilvimarinus chinensis. Based on phylogenetic, genomic, chemotaxonomic and phenotypic studies, strain HB14T was classified as a representative of a novel species in the genus Gilvimarinus, for which the name Gilvimarinus xylanilyticus sp. nov. was proposed. The type strain is HB14T (=CCTCC AB 2022109T = KCTC 92379T). Four 1,3-xylanases secreted by strain HB14T were identified based on genome and secretome analyses, and the two (Xyn65 and Xyn80) with relatively higher abundance in secretome were successfully expressed in Escherichia coli and biochemically characterized. They showed the highest activity at pH 6.0-7.0 and 40°C and released mainly 1,3-xylobiose and 1,3-xylotriose from 1,3-xylan. These data suggest that strain HB14T acts as a player in marine 1,3-xylan degradation and recycling and that its extracellular 1,3-xylanases may have a good potential in 1,3-xylooligosaccharides preparation.

[Impact of smoking and smoking cessation on long-term outcome of patients after coronary artery bypass grafting].

OBJECTIVE: To determine the impact of smoking behaviors on long-term outcomes of coronary artery bypass grafting (CABG). METHODS: We conducted this survey in 2541 consecutive patients who underwent CABG in Fu Wai hospital from January 1, 2004 to December 30, 2005. The preoperative and postoperative smoking habits were obtained. The patients were divided into never smokers and ever smokers. The ever smokers were further divided into the current smokers who smoked before and after CABG and former smokers who stopped smoking before CABG, quitters who stopped smoking after CABG. Death, major adverse cardiovascular or cerebrovascular events and angina pectoris were observed. The relative risk of adverse events in different patients were analyzed by univariate and multivariate Cox analysis. RESULTS: The patients were followed up for 4.27 to 6.41 years (average 5.09 years). After CABG, the percentage of persistent smoking patients was 22.1%. After adjusting baseline characteristics, relative risk for tumor related death (RR: 2.38, 95%CI: 1.06 - 5.36), major adverse cardiovascular or cerebrovascular events (RR: 1.26, 95%CI: 1.01 - 1.57) and angina pectoris (RR: 1.29, 95%CI: 1.04 - 1.59) were significantly higher in ever smokers than in never smokers. Similarly, relative risk of death from all causes (RR: 2.60, 95%CI: 1.53 - 4.46), cardiac death (RR: 2.51, 95%CI: 1.32 - 4.78), tumor cause death (RR: 5.12, 95%CI: 2.08 - 12.59), major adverse cardiovascular or cerebrovascular events (RR: 1.83, 95%CI: 1.42 - 2.34) and angina pectoris (RR: 1.69, 95%CI: 1.33 - 2.16) were also significantly higher in current smokers than in never smokers. Outcome was similar between patients who stopped smoking and never smokers (all P > 0.05). CONCLUSIONS: Smoking prevalence is still high in patients after CABG in China. Persistent smoking is associated with higher rates of mortality and morbidity after CABG while smoking cessation is associated with reduction of morbidity and mortality in patients after CABG.

Application of unicompartmental knee arthroplasty in the treatment of knee osteoarthritis.

OBJECTIVE: For the treatment of medial compartment knee osteoarthritis, unicompartmental knee arthroplasty was chosen on the basis of the clinical effects and the rate of prosthesis survival. A retrospective analysis was performed on 500 patients with osteoarthritis of the medial compartment knee treated by unicompartmental knee arthroplasty between April 2007 and April 2017. The cohort was comprised of 176 males and 324 females, aged (61.12 ± 8.0) years old. The clinical treatment was evaluated in terms of the range of movement (ROM), the Knee Society score (KSS), and the Oxford knee score. RESULTS: The follow-up lasted 1.59-11.60 years. Grouped in terms of age, 133 cases were in the middle-age, 295 were in the old-age group, and 72 in the advanced-age group. Against the Iwano classification of the patellofemoral joint, 104 cases were graded 0-1; 179 were graded 2; 182 were graded 3 and 35 were graded 4. The KSS score improved from (59 ± 5.6) points before the operation to (93 ± 3.5) points after the operation. The OKS score increased from (24 ± 2.4) points before the operation to (45 ± 3.8) points after the operation. The ROM of knee joint was (111 ± 6.8)° before the operation and was (117 ± 9.7)° after the operation. The 10-year survival rate of the prosthesis was 96%. CONCLUSION: UKA is one of the treatments for medial compartmental knee osteoarthritis. The issues, such as age and patellofemoral joint degeneration, can be addressed by careful selection of patients and precise operational manipulation.

Diversity of Marine 1,3-Xylan-Utilizing Bacteria and Characters of Their Extracellular 1,3-Xylanases.

1,3-xylan is present in the cell walls of some red and green algae and is an important organic carbon in the ocean. However, information on its bacterial degradation is quite limited. Here, after enrichment with 1,3-xylan, the diversity of bacteria recovered from marine algae collected in Hainan, China, was analyzed with both the 16S rRNA gene amplicon sequencing and the culture-dependent method. Bacteria recovered were affiliated with more than 19 families mainly in phyla Proteobacteria and Bacteroidetes, suggesting a high bacterial diversity. Moreover, 12 strains with high 1,3-xylanase-secreting ability from genera Vibrio, Neiella, Alteromonas, and Gilvimarinus were isolated from the enrichment culture. The extracellular 1,3-xylanases secreted by Vibrio sp. EA2, Neiella sp. GA3, Alteromonas sp. CA13-2, and Gilvimarinus sp. HA3-2, which were taken as representatives due to their efficient utilization of 1,3-xylan for growth, were further characterized. The extracellular 1,3-xylanases secreted by these strains showed the highest activity at pH 6.0-7.0 and 30-40°C in 0-0.5M NaCl, exhibiting thermo-unstable and alkali-resistant characters. Their degradation products on 1,3-xylan were mainly 1,3-xylobiose and 1,3-xylotriose. This study reveals the diversity of marine bacteria involved in the degradation and utilization of 1,3-xylan, helpful in our understanding of the recycling of 1,3-xylan driven by bacteria in the ocean and the discovery of novel 1,3-xylanases.

Porous carbon-confined Co x S y nanoparticles derived from ZIF-67 for boosting lithium-ion storage.

Reasonable regulation and synthesis of hollow nanostructure materials can provide a promising electrode material for lithium-ion batteries (LIBs). In this work, utilizing a metal-organic framework (MOF, ZIF-67) as the raw material and template, a composite of Co x S y with a carbon shell is successfully formed through a hydrothermal vulcanization and a subsequent high temperature sintering process. The as-obtained Co x S y (700) material sintered at 700 °C has a large specific surface area, and at the same time possesses a hollow carbon shell structure. Benefiting from unique structural advantages, the volume change during the electrochemical reaction can be well alleviated, and thus the structural stability is greatly improved. The presence of the carbon matrix can also offer sufficient ion/electron transfer channels, contributing to the enhanced electrochemical performance. As a result, the Co x S y (700) electrode can deliver an excellent capacity of 875.6 mA h g-1 at a current density of 100 mA g-1. Additionally, a high-capacity retention of 88% is achieved after 1000 cycles when the current density is increased to 500 mA g-1, and exhibiting a prominent rate capability of 526.5 mA h g-1, simultaneously. The novel synthesis route and considerable electrochemical properties presented by this study can afford guidance for the exploration of high-performance cobalt sulfide anodes in LIBs.

[Surgical treatment of aortico-left ventricular tunnel].

OBJECTIVE: To review 9 aortico-left ventricular tunnel (ALVT) patients in our hospital, describe the clinical features, diagnosis, treatments and follow-up. METHODS: We identified 9 patients from July 2002 to August 2008. Clinical and surgical details were reviewed. 7 patients were in NYHA class I and 2 in class III, 8 of 9 patients were diagnosed by echocardiography before operation. RESULTS: All patients underwent surgery under standard cardiopulmonary bypass. 2 with direct suture, 5 by patch closure of the aortic end and 1 by patch closure of both aortic end and left ventricular end of the AVLT. 1 underwent aortic valve replacement after incision of the ALVT. One patient died 2 month after operation because of endocarditis and acute heart failure. At follow-up (3 month to 6 years), 3 patients were in NYHA class I, 3 in Class II, 1 in class III and missed 1. No aortic regurgitation or trace in 2, little in 1, little to moderate in 2. The aortic mechanical valve is normal in 1 and paravalvular leakage in 1 patient. CONCLUSION: Aortico-left ventricular tunnel is a rare cardiac malformation with a good post-operative outcome. Surgery is an effective treatment. Long-term follow-up for post-operation is essential.

Changes in life satisfaction and self-esteem in patients with adolescent idiopathic scoliosis with and without surgical intervention.

STUDY DESIGN: Pre-/poststudy comparing surgical and nonsurgical treatment. OBJECTIVE: To identify whether orthopedic spinal surgery can effectively improve life satisfaction and self-esteem in patients with adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: There have been many studies about the effect of spinal deformity and its various treatments on the mental health of patients with adolescent idiopathic scoliosis. Scoliosis has been reported to have a negative effect on the life quality and mental health of patients. It has also been reported that no matter what the treatment, the existence of scoliosis is a risk factor for depression. However, there has been no report on whether orthopedic spinal surgery affects the life satisfaction and self-esteem of scoliosis patients. METHODS: Forty-six patients with Cobb angles of more than 30° were recruited from a group of patients that were treated from January 2007 to August 2007. Twenty-one patients with Cobb angles of more than 40° underwent surgical correction while the remaining patients received regular observation (n = 11) or bracing (n = 14). Self-esteem and life satisfaction were assessed before and approximately 1 year after treatment using previously validated scales. RESULTS: There were no between-group differences in age, sex, or major curve location between the surgically and nonsurgically treated groups. The major curve Cobb angle decreased significantly following treatment in the surgically treated (52° ± 10° to 15° ± 8°, P < 0.001), but not the nonsurgically treated group (37° ± 9° to 39° ± 8°, P = 0.4419) using paired t tests. There were no preintervention between-group differences in life satisfaction (8 ± 1 vs. 7 ± 10); however, preintervention self-esteem scores were significantly higher in the nonsurgically treated group (28 ± 4 vs. 25 ± 3, P = 0.008). Postintervention, both life satisfaction (9 ± 1) and self-esteem (31 ± 2) scores improved significantly (P < 0.05) in the surgically treated, but not the nonsurgically treated group (7 ± 1 and 24 ± 5, respectively). Self-esteem levels decreased significantly in the nonsurgically treated group (P < 0.05) Postintervention self-esteem and life satisfaction scores were significantly higher in the surgically treated than the nonsurgically treated group (P < 0.05). CONCLUSIONS: These findings indicate that surgical correction of adolescent idiopathic scoliosis in eligible patients can lead not only to curve correction, but also to an increase self-esteem and life satisfaction.

Decrease of self-concept in adolescent patients with mild to moderate scoliosis after conservative treatment.

STUDY DESIGN: Comparative study. OBJECTIVE: To analyze the effect of conservative treatment on self-concept in patients with mild to moderate scoliosis. SUMMARY OF BACKGROUND DATA: The choice of surgery or conservative treatment in adolescent idiopathic scoliosis is usually done on the basis of the magnitude of the initial Cobb angle in these patients. However, mental effect of the therapy choice should be considered. METHODS: Between August 2006 and December 2008, 65 patients with adolescent idiopathic scoliosis were selected for this study. Twenty-two patients with Cobb angles between 20° and 40° received conservative treatment, 18 patients with Cobb angles between 40° and 50° received conservative treatment, and 25 patients with Cobb angles between 40° and 50° received surgical treatment. All subjects were required to fill the Children's Self-Concept Scale at the beginning of the study and at the follow-up visit 1 year later. Scores on this scale were compared among the three different groups, and between the initial visit and the follow-up visit in each group. RESULTS: At the initial test, the total self-concept score was significantly higher in the group of patients with Cobb angles between 20° and 40° than in the two groups with Cobb angles between 40° and 50°. At the follow-up visit, the total self-concept score had increased significantly in the surgically treated group (Cobb angle between 40° and 50°), however, it had decreased in the two conservatively treated groups. No significant difference was seen between the two conservatively treated groups in the amount by which the self-concept score had decreased at follow-up. CONCLUSION: In terms of mental health, conservative treatment is not ideal for patients with mild to moderate scoliosis, and in particular, it is not conducive to mental health in patients with Cobb angles between 40° and 50°.

An improved correction method for reducing off-focal artifacts in CT imaging.

This paper presents a new method to reduce halo artifacts in Computed Tomography (CT) images, which blur the image edges and descend the image quality. Off-focal radiation is main ill factor leading to these halo artifacts. To reduce the off-focal effects, we adopt a pre-processing method to filter the sampling data directly before reconstruction, instead of post-processing method such as edge enhancing on the reconstructed images. Different from the prior pre-processing method, we also present a new and more practical method to obtain convolution kernel and a simpler formula in this paper. Results show that after calibration by the new practical method, the off-focal radiation effects were reduced efficiently, the edges were enhanced and the image quality was improved without increasing noise.

A correction method for nonlinear artifacts in CT imaging.

This work presents a new method to reduce nonlinear artifacts in computed tomography (CT). Based on the traditional water-equivalent beam hardening correction method, a new systematic iterative algorithm has been designed to modify the original spectrum, which is under the influences of certain added filter materials and some unknown factors. By incorporating the characters of polychromatic beam hardening and the insensibility and nonuniformity of detectors into consideration, a new polynomial function curve is calculated. The curve can calibrate CT raw data and reduce the nonlinear artifacts, such as shading artifacts, dark artifacts, cupping artifacts and ring artifacts, in soft tissue. Comparing with the traditional water-equivalent correction, results show that this method can significantly improve the image quality. Meanwhile, the method is pre-processing and will not increase the normal reconstruction time. That is, all the time-consuming works can be done before scanning patients. However, it is still depending on the size of phantoms currently used, and more detailed works need to be done in the future.