The mechanisms linking perceived stress to pilots' safety attitudes: a chain mediation effect of job burnout and cognitive flexibility.

Introduction: Pilots' safety attitude is crucial for aviation safety. Current research shows a correlation between perceived stress and safety attitude, yet the mechanism underlying this association remains unclear. Against the backdrop of heightened attention to pilots' stress, this study aims to thoroughly explore the inherent connection between pilot safety attitudes and their perceived stress, offering targeted insights into preventing and addressing safety attitude issues arising from pilot stress. Methods: Through path analysis of questionnaire data from 106 civil aviation pilots in China, this study systematically investigates the roles of job burnout and cognitive flexibility in the relationship between perceived stress and safety attitude. The study reveals the chain-mediated mechanism of these two factors. Results: The results demonstrate a significantly negative correlation between pilots' perceived stress and safety attitude, with cognitive flexibility and job burnout fully mediating this relationship, and cognitive flexibility affecting job burnout. A detailed analysis of the three dimensions of job burnout reveals varying impacts of emotional exhaustion, depersonalization, and reduced personal accomplishment on the aforementioned path. The research model exhibits a good fit (GFI=0.902), providing new theoretical perspectives on the association between pilots' perceived stress and safety attitude. Discussion: The findings offer practical implications for improving pilots' safety attitude by proposing targeted measures to alleviate the adverse impacts of perceived stress on safety attitude, thereby promoting aviation safety.

A high-affinity RBD-targeting nanobody improves fusion partner's potency against SARS-CoV-2

A key step to the SARS-CoV-2 infection is the attachment of its Spike receptor-binding domain (S RBD) to the host receptor ACE2. Considerable research have been devoted to the development of neutralizing antibodies, including llama-derived single-chain nanobodies, to target the receptor-binding motif (RBM) and to block ACE2-RBD binding. Simple and effective strategies to increase potency are desirable for such studies when antibodies are only modestly effective. Here, we identify and characterize a high-affinity synthetic nanobody (sybody, SR31) as a fusion partner to improve the potency of RBM-antibodies. Crystallographic studies reveal that SR31 binds to RBD at a conserved and greasy site distal to RBM. Although SR31 distorts RBD at the interface, it does not perturb the RBM conformation, hence displaying no neutralizing activities itself. However, fusing SR31 to two modestly neutralizing sybodies dramatically increases their affinity for RBD and neutralization activity against SARS-CoV-2 pseudovirus. Our work presents a tool protein and an efficient strategy to improve nanobody potency.

Potent synthetic nanobodies against SARS-CoV-2 and molecular basis for neutralization

SARS-CoV-2, the causative agent of COVID-191, recognizes host cells by attaching its receptor-binding domain (RBD) to the host receptor ACE22-7. Neutralizing antibodies that block RBD-ACE2 interaction have been a major focus for therapeutic development8-18. Llama-derived single-domain antibodies (nanobodies, [~]15 kDa) offer advantages including ease of production and possibility for direct delivery to the lungs by nebulization19, which are attractive features for bio-drugs against the global respiratory disease. Here, we generated 99 synthetic nanobodies (sybodies) by in vitro selection using three libraries. The best sybody, MR3 bound to RBD with high affinity (KD = 1.0 nM) and showed high neutralization activity against SARS-CoV-2 pseudoviruses (IC50 = 0.40 g mL-1). Structural, biochemical, and biological characterization of sybodies suggest a common neutralizing mechanism, in which the RBD-ACE2 interaction is competitively inhibited by sybodies. Various forms of sybodies with improved potency were generated by structure-based design, biparatopic construction, and divalent engineering. Among these, a divalent MR3 conjugated with the albumin-binding domain for prolonged half-life displayed highest potency (IC50 = 12 ng mL-1) and protected mice from live SARS-CoV-2 challenge. Our results pave the way to the development of therapeutic nanobodies against COVID-19 and present a strategy for rapid responses for future outbreaks.

An iliac-crest-preserving iliac wing bone graft harvesting technique / 中华骨科杂志

Objective@#To evaluate the clinical application effects of an iliac-crest-preserving iliac wing bone graft harvesting technique and the bone regenerative ability of the donor site after harvesting.@*Methods@#From January 2016 to June 2017, a series of 39 patients including 28 men and 11 women aged between 16 and 59 y (35±13 y in average) were prospectively collected to treat bone defects using the iliac-crest-preserving iliac wing bone graft harvesting technique. The patient cohort included 38 ipsilateral and 1 bilateral bone harvests taken from 15 femoral fracture non-unions, 8 tibial fracture non-unions, 11 femoral head necroses (hip preserving surgery), 1 tuberculosis deriving hip arthritis with bone defect (total hip arthroplasty), 2 hip prosthesis loosenings (revision), and 2 proximal femoral benign tumors. All patients were treated through comprehensive surgeries containing autologous iliac bone grafting. The surgical time, blood loss, bone graft volume, 24 h post-operative visual analogue scale (VSA) at the iliac surgical site, complications, and bone regeneration of the donor site were documented and evaluated.@*Results@#In the 39 patients (40 sides), the average surgical time was 25±4 min, average blood loss was 79±23 ml, average bone graft volume was 27±6 cm3. The average 24 h post-operative VAS at the iliac surgical site was 1.8±0.7 points. The VSA at the 6 week later and thereafter were 0 in all patients. The iliac incisions in 38 patients (39 sides) were healed uneventfully. However, seroma at the iliac surgical site emerged in 1 patient at the 6th post-operative day in the manner of serous exudation and was treated successfully with non-operative measures. None infections and lateral femoral cutaneous nerve injuries took place. Iatrogenic non-displaced iliac crest fractures happened in the very first 2 patients when taking the crest as a pivot to pry up the graft, which united without special cure at the 3 month post-operative. This complication was completely avoided when shifting the pivot to the anterior pillar containing the anterior iliac spines. None pelvic fractures and heterotopic ossifications took place. Post-operative radiographical examinations revealed that the bone defects at the donor site shrank through bone regeneration, that mamillary or canine-tooth-shaped bone formation occurred in some of the cases, and that none complete bone regeneration took place to eliminate the bone defect at the donor. There were 12 patients in whom pre- and post-operative computed tomographic scans necessitated by the disease were prescribed, which facilitated the measuring of the bone defect at the donor site. The measurement of 13 sides revealed that the bone defects were decreased more or less: the average immediate post-operative bone defect was 25.7±6.5 cm2, the average 12 month post-operative bone defect was 12.7±5.3 cm2.@*Conclusion@#The iliac wing bone graft harvesting technique suggested here is safe and less invasive, in the premise of preserving the iliac crest and retaining the figure of the surgical site, it can harvest a large amount of iliac wing bone graft and reserve the bone regenerative ability of the donor site

An iliac-crest-preserving iliac wing bone graft harvesting technique / 中华骨科杂志

Objective To evaluate the clinical application effects of an iliac-crest-preserving iliac wing bone graft harvesting technique and the bone regenerative ability of the donor site after harvesting.Methods From January 2016 to June 2017,a series of 39 patients including 28 men and 11 women aged between 16 and 59 y (35± 13 y in average) were prospectively collected to treat bone defects using the iliac-crest-preserving iliac wing bone graft harvesting technique.The patient cohort included 38 ipsilateral and 1 bilateral bone harvests taken from 15 femoral fracture non-unions,8 tibial fracture non-unions,11 femoral head necroses (hip preserving surgery),1 tuberculosis deriving hip arthritis with bone defect (total hip arthroplasty),2 hip prosthesis loosenings (revision),and 2 proximal femoral benign tumors.All patients were treated through comprehensive surgeries containing autologous iliac bone grafting.The surgical time,blood loss,bone graft volume,24 h post-operative visual analogue scale (VSA) at the iliac surgical site,complications,and bone regeneration of the donor site were documented and evaluated.Results In the 39 patients (40 sides),the average surgical time was 25±4 min,average blood loss was 79±23 ml,average bone graft volume was 27±6 cm3.The average 24 h post-operative VAS at the iliac surgical site was 1.8±0.7 points.The VSA at the 6 week later and thereafter were 0 in all patients.The iliac incisions in 38 patients (39 sides) were healed uneventfully.However,seroma at the iliac surgical site emerged in 1 patient at the 6th post-operative day in the manner of serous exudation and was treated successfully with non-operative measures.None infections and lateral femoral cutaneous nerve injuries took place.Iatrogenic non-displaced iliac crest fractures happened in the very first 2 patients when taking the crest as a pivot to pry up the graft,which united without special cure at the 3 month post-operative.This complication was completely avoided when shifting the pivot to the anterior pillar containing the anterior iliac spines.None pelvic fractures and heterotopic ossifications took place.Post-operative radiographical examinations revealed that the bone defects at the donor site shrank through bone regeneration,that mamillary or canine-tooth-shaped bone formation occurred in some of the cases,and that none complete bone regeneration took place to eliminate the bone defect at the donor.There were 12 patients in whom pre-and post-operative computed tomographic scans necessitated by the disease were prescribed,which facilitated the measuring of the bone defect at the donor site.The measurement of 13 sides revealed that the bone defects were decreased more or less:the average immediate post-operative bone defect was 25.7±6.5 cm2,the average 12 month post-operative bone defect was 12.7±5.3 cm2.Conclusion The iliac wing bone graft harvesting technique suggested here is safe and less invasive,in the premise of preserving the iliac crest and retaining the figure of the surgical site,it can harvest a large amount of iliac wing bone graft and reserve the bone regenerative ability of the donor site.

An efficient way to orientate S1 iliosacral screw guide-pin verified by CT / 中华创伤骨科杂志

Objective To introduce an efficient way to orientate S1 iliosacral screw guide-pin verified by CT.Methods The pelvic axial CT data in DICOM format of 180 adults between July 2017 and June 2018 were retrieved from the database of Imaging Center,Luoyang Orthopaedic Hospital of Henan Province.The data were input into the software Mimics 20.0 to display the axial,coronal and sagittal sectional views of the pelvis.On the axial CT sectional view displaying the largest osseous pathway in the S1 segment,a virtual iliosacral screw and its virtual guide-pin were accurately placed into the sacral body in an oblique fashion.In the design of ideal insertion,the virtual screw and guide-pin were truly in the pelvic transverse plane when they were located exactly in the pelvic axial CT sectional view,and they intersected the outer iliac table at the start-point which restricted the guide-pin's location,and angulated with the pelvic coronal plane (represented by a line connecting the most dorsal points of bilateral ilia) at an angle (α) which limited the guide-pin's orientation.After three-dimensional pelvic models of the standard lateral sacral view and the pelvic outlet and inlet views in each patient were calculated,they were displayed in a transparent manner using the software,followed by the virtual insertion of the screw and guide-pin.After the start-point was established on the standard lateral sacral view,the guide-pin was orientated into the pelvic transverse plane and at the guide-pin's α angle relative to the pelvic coronal plane,and subsequently inserted into the ilium shallowly for stabilization.The pelvic outlet and inlet views were taken to judge the guide-pin's orientation.If fine orientation was verified,the guide-pin was advanced to its final position,followed by virtual insertion of an iliosacral screw over the guide-pin.After the virtual insertion was completed,the axial,coronal and sagittal CT sectional views of the pelvis were scrutinized to evaluate the accuracy of insertion.Results After all the guide-pins were orientated in the 180 adults (360 sides) on the true sacral lateral view according to the above way,their orientations on the pelvic outlet and inlet views were 100％ fine,leaving further adjustment unnecessary.The intraosseous insertions of the virtual screws and guide-pins were 100％ accurate and safe on the CT sectional images.Conclusion The way introduced here can theoretically guarantee accurate orientations of the guide-pin on the pelvic outlet and inlet views with no more complex guide-pin adjustments,assuring insertion accuracy and enhancing surgical efficiency.

Modified percutaneous retrograde intramedullary screwing into superior pubic ramus or anterior acetabular column for pelvic and acetabular injury / 中华创伤骨科杂志

Objective To evaluate the safety and accuracy of modified percutaneous retrograde intramedullary screwing into the superior pubic ramus or anterior acetabular column for pelvic and acetabular injury.Methods A retrospective analysis was conducted of the 23 patients with pelvic and acetabular injury who had been treated with modified percutaneous retrograde intramedullary screwing into the superior pubis ramus or anterior acetabular column from June 2015 to June 2017 in Luoyang Orthopaedic Hospital of Henan Province.They were 12 men and 11 women,aged from 22 to 88 years (mean,53 years).The injury included 17 pelvic fractures,4 acetabular fractures,and 2 acetabular plus pelvic fractures.The safety and accuracy of screwing were assessed by postoperative physical and imaging examinations.The number of fluoroscopy and operative time were documented for each retrograde intramedullary screwing into the pubic symphysis or acetabular anterior column.The quality of fracture reduction was evaluated by the Mata criteria postoperatively.The Majeed and the Harris scores were used to evaluate the functional recovery of the pelvis and acetabulum at the last follow-ups.Results A total of 31 intramedullary screws were placed in the 23 patients.For insertion of one screw,the operative time ranged from 15 to 50 min (average,35 min) and the number of fluoroseopy from 32 to 55 times (average,45 times).Postoperative physical examinations revealed no iatrogenic neurovascular lesion and uneventful healing of incisions in all the patients.Postoperative imaging examinations showed that 29 screws were located completely in the bone and 2 ones protruded the cortical bone of the pubic anterior border;all the screws did not protrude into the acetabulum or broke through the pubic symphysis or the pubic cortex.By the Matta criteria,the postoperative fracture reduction was rated as excellent in 17 cases,good in 5 and fair in one,giving an excellent to good rate of 95.7％.Of this series,19 were followed up for 6 to 24 months (mean,13 months).All the fractures healed after 3 months.The Majeed scores at the last follow-up for the 13 patients with pelvic fracture were excellent in 12 and good in one.The Harris scores at the last follow-up for the 6 patients with acetabular fracture (including the 2 with pelvic fracture) were excellent in 5 and fair in one.Conclusion The modified percutaneous retrograde intramedullary screwing into the superior pubic ramus or anterior acetabular column is safe,convenient and precise,effectiyely reducing radiation and operative time.