Inverted Region in Electrochemical Reduction of CO2 Induced by Potential-Dependent Pauli Repulsion.

Electrochemical CO2 reduction reaction (eCO2RR) is of great significance to energy and environmental engineering, while fundamental questions remain regarding its mechanisms. Herein, we formulate a fundamental understanding of the interplay between the applied potential (U) and kinetics of CO2 activation in eCO2RR on Cu surfaces. We find that the nature of the CO2 activation mechanism in eCO2RR varies with U, and it is the sequential electron-proton transfer (SEPT) mechanism dominant at the working U but switched to the concerted proton-electron transfer (CPET) mechanism at highly negative U. We then identify that the barrier of the electron-transfer step in the SEPT mechanism exhibits an inverted region as U decreases, which originates from the rapidly rising Pauli repulsion in the physisorption of CO2 with decreasing U. We further demonstrate catalyst designs that effectively suppress the adverse effect of Pauli repulsion. This fundamental understanding may be general for the electrochemical reduction reactions of closed-shell molecules.

Clinical study of modified INFIX combined with sacroiliac joint screws for pelvic instable injuries.

OBJECTIVE: The INFIX technique is becoming one of the most commonly performed surgical procedures for anterior pelvic ring instability injuries. The purpose of this article is to compare the clinical outcomes of modified anterior subcutaneous internal fixation (M-INFIX) with conventional anterior subcutaneous internal fixation (C-INFIX) for anterior pelvic ring instability injuries. PATIENTS AND METHODS: A retrospective analysis of 36 cases of unstable pelvic injuries treated operatively at our institution, 20 of which were treated with C-INFIX and 16 with M-INFIX. Data collected included age, gender, ISS score, fracture typing, operative time, operative bleeding, postoperative complications, fracture healing time, Matta score, Majeed score, and follow-up time. Statistical sub-folding of each variable between the two groups was performed. RESULTS: There was no statistical difference between the C-INFIX and M-INFIX groups in terms of age, gender, ISS (Injury Severity Score), follow-up time, fracture typing, fracture healing time, and Majeed score (P > 0.05). the M-INFIX had a significantly lower incidence of postoperative complications than the C-INFIX group, especially in the incidence of Lateral femoral cutaneous nerve (LFCN) injury (P < 0.05). In contrast, the M-INFIX group had statistically higher operative time, intraoperative bleeding, and Matta score than the C-INFIX group (P < 0.05). CONCLUSION: This study was based on a modified application of the surgical experience with C-INFIX and showed better clinical outcomes in terms of complication rates and quality of repositioning than the conventional surgical approach. These findings indicate that further analytical studies of this study would be valuable.

Differential idiotype utilization for the in vivo type 14 capsular polysaccharide-specific Ig responses to intact Streptococcus pneumoniae versus a pneumococcal conjugate vaccine.

Murine IgG responses specific for the capsular polysaccharide (pneumococcal capsular polysaccharide serotype 14; PPS14) of Streptococcus pneumoniae type 14 (Pn14), induced in response to intact Pn14 or a PPS14-protein conjugate, are both dependent on CD4(+) T cell help but appear to use marginal zone versus follicular B cells, respectively. In this study, we identify an idiotype (44.1-Id) that dominates the PPS14-specific IgG, but not IgM, responses to intact Pn14, isolated PPS14, and Group B Streptococcus (strain COH1-11) expressing capsular polysaccharide structurally identical to PPS14. The 44.1-Id, however, is not expressed in the repertoire of natural PPS14-specific Abs. In distinct contrast, PPS14-specific IgG responses to a soluble PPS14-protein conjugate exhibit minimal usage of the 44.1-Id, although significant 44.1-Id expression is elicited in response to conjugate attached to particles. The 44.1-Id elicited in response to intact Pn14 was expressed in similar proportions among all four IgG subclasses during both the primary and secondary responses. The 44.1-Id usage was linked to the Igh(a), but not Igh(b), allotype and was associated with induction of relatively high total PPS14-specific IgG responses. In contrast to PPS14-protein conjugate, avidity maturation of the 44.1-Id-dominant PPS14-specific IgG responses was limited, even during the highly boosted T cell-dependent PPS14-specific secondary responses to COH1-11. These results indicate that different antigenic forms of the same capsular polysaccharide can recruit distinct B cell clones expressing characteristic idiotypes under genetic control and suggest that the 44.1-Id is derived from marginal zone B cells.

Effects of Freeze-Thaw Cycles on Axial Compression Behaviors of UHPC-RC Composite Columns.

Ultra-high performance concrete (UHPC) with excellent durability has broad application prospects in improving the durability of reinforced concrete (RC) structures. To clarify the influence of freeze-thaw cycles on the axial compression performance of UHPC-RC composite columns, axial compression tests were carried out on composite columns with different cycles (0, 100, 200, 300 cycles) and stirrup spacing (35, 70, 105 mm). The results showed that the UHPC shell did not fall off when the composite column was destroyed, even in the freeze-thaw environment. Under the action of freeze-thaw cycles, the peak load Nu,t and initial elastic modulus E of the composite column decreased, but the ductility coefficient µ increased. Increasing the stirrup spacing could significantly improve the ductility of the composite column. After 100 freeze-thaw cycles, the ductility coefficient µ of the 35 mm stirrup spacing specimen was 112.6% higher than that of the 105 mm specimen. A prediction model for the bearing capacity of UHPC-RC composite columns under freeze-thaw cycles was established, and the predicted results were in good agreement with the experimental results. This study lays a theoretical and experimental foundation for the application and design of UHPC-RC composite columns in the freeze-thaw environment.

[Experiences with the infra-acetabular screw placement technique in acetabular fracture surgery].

Objective: To investigate the application experiences and effectiveness of the infra-acetabular screw (IAS) placement technique in acetabular fracture surgery. Methods: A clinical data of 34 patients with complex acetabular fractures with anterior and posterior columns separation, who were admitted between January 2019 and October 2023 and treated with IAS fixation, was retrospectively analyzed. There were 23 males and 11 females with an average age of 55.3 years (range, 18-78 years). The acetabular fractures caused by traffic accident in 20 cases, falling from height in 12 cases, crushing injury in 1 case, and bruising with a heavy object in 1 case. According to the Letournel-Judet classification, there were 7 cases of anterior column fracture, 8 cases of anterior wall/column plus posterior hemi-transverse fracture, 2 cases of T-shaped fracture, and 17 cases of both-column fracture. The time from injury to surgery was 4-21 days (mean, 8.6 days). The time of IAS placement and the intraoperative blood loss were recorded. After surgery, the X-ray film and CT scan were re-examined, and the modified Matta score was used to assess the quality of fracture reduction. The trajectory of IAS in the channel was analyzed based on CT scan, and the screw length was measured. During follow-up, the fracture healing was observed and the hip function was assessed according to the modified Merle d'Aubigné-Postel scoring system at last follow-up. Results: The IAS was successfully implanted in all 34 patients. The length of IAS ranged from 70 to 100 mm (mean, 86.2 mm). The time of IAS placement ranged from 10 to 40 minutes (mean, 20.7 minutes). The intraoperative blood loss ranged from 520 to 820 mL (mean, 716.8 mL). All patients were followed up 8-62 months (mean, 21.8 months). After surgery, 4 patients developed lateral femoral cutaneous nerve injury, 2 developed popliteal vein thrombosis of the lower extremity, 3 developed incision infection, and no surgical complication such as arteriovenous injury or obturator nerve palsy occurred. At last follow-up, the hip function was rated as excellent in 14 cases, good in 13 cases, fair in 4 cases, and poor in 3 cases according to the Merle d'Aubigné-Postel scoring system, with an excellent and good rate of 79.41%. Imaging re-examined showed that the quality of fracture reduction was rated as excellent in 9 cases, good in 19 cases, and poor in 6 cases according to the modified Matta score, with an excellent and good rate of 82.35%; and 25 (73.53%) IAS trajectories were located in the channel. All fractures obtained bony union, and the healing time was 12-24 weeks (mean, 18 weeks). During follow-up, there was no loosening or fracture of the plate and screws. Conclusion: IAS placement technique can effectively strengthen internal fixation and prevent fracture re-displacement, making it a useful adjunct for treating complex acetabular fractures with anterior and posterior columns separation.

[Analysis of the therapeutic effect of trochanteric flip osteotomy combined with Kocher-Langenbeck approach for high acetabular posterior wall fracture].

OBJECTIVE: Evaluation of the clinical efficacy of f trochanteric flip osteotomy combined with Kocher-Langenbeck approach for high acetabular posterior wall fracture. METHODS: Between January 2020 and December 2022, 20 patients with high acetabular posterior wall fractures were retrospectively analyzed, including 12 males and 8 females, aged 18 to 75 years old. They were divided into two groups according to the different surgical methods. Ten patients were treated with greater trochanteric osteotomy combined with Kocher-Langenbeck approach as the observation group, including 5 males and 5 females, aged from 18 to 75 years old. Ten patients were treated with Kocher-Langenbeck approach alone as the control group, including 7 males and 3 females, aged from 18 to 71 years old. Matta reduction criteria were used to evaluate the reduction quality of the two groups, and Harris score was used to compare the hip function of the two groups at the latest follow-up. The operation time, blood loss and postoperative complications of the two groups were analyzed. RESULTS: All patients were followed up for 10 to 24 months. According to the Matta fracture reduction quality evaluation criteria, the observation group achieved anatomical reduction in 6 cases, satisfactory reduction in 3 cases, and unsatisfactory reduction in 1 case, while the control group only achieved anatomical reduction in 3 cases, satisfactory reduction in 3 cases, and unsatisfactory reduction in 4 cases. At the final follow-up, the Harris hip score ranged from 71.4 to 96.6 in the observation group and 65.3 to 94.5 in the control group. According to the results of Harris score. The hip joint function of the observation group was excellent in 6 cases, good in 3 cases, and fair in 1 case. The hip joint function of the control group was excellent in 2 cases, good in 3 cases, fair in 3 cases, and poor in 2 cases. In the observation group, the intraoperative blood loss ranged from 300 to 700 ml, and the operation duration ranged from 120 to 180 min;in the control group, the intraoperative blood loss ranged from 300 to 650 ml, and the operation duration ranged from 100 to 180 min. Complications in the observation group included 1 case of traumatic arthritis and 1 case of heterotopic ossification, while complications in the control group included 3 cases of traumatic arthritis, 3 cases of heterotopic ossification and 1 case of hip abduction weakness. CONCLUSION: Trochanteric flip osteotomy combined with the Kocher-Langenbeck approach significantly improved anatomical fracture reduction rates, enhanced excellent and good hip joint function outcomes, and reduced surgical complication incidence compared to the Kocher-Langenbeck approach alone. Clinical application of this combined approach is promising, although larger studies are needed for further validation.

Combined pelvic and acetabular injuries: clinical features and treatment strategies of a unique injury pattern.

BACKGROUND: To explore the clinical characteristics of patients with unstable pelvic fractures combined with acetabular fractures and to discuss the treatment strategies for such patients to help guide treatment. METHODS: We retrospectively assessed 24 patients admitted to our hospital from June 2018 to June 2022 with unstable pelvic fractures combined with acetabular fractures, including 15 male patients and 9 female patients with a mean age of 44.8 years. According to the Tile pelvic fracture classification, 15 cases were type B, and 9 cases were type C. The acetabular fractures were classified using the Letournel-Judet classification. There were 8 transverse fractures, 4 transverse and posterior wall fractures, 3 anterior and posterior hemitransverse fractures, 6 both-column fractures, 2 T-shaped fractures and 1 anterior column fracture. We recorded the cause of the patient's injury and vital signs on admission and assessed the patient's treatment strategy and prognosis. RESULTS: All patients completed the surgery successfully, and the follow-up ranged from 6 to 42 months, with a mean of 23 months. The healing time for pelvic fractures ranged from 11 to 21 weeks, with a mean of 14.8 weeks, and the postoperative displacement of the posterior pelvic ring ranged from 1.2 to 9.0 mm, with a mean of 3.5 mm. The final clinical outcome at follow-up was evaluated using the Majeed scale: excellent in 11 cases, good in 10 cases and fair in 3 cases; the excellent rate was 87.5%. The time to healing of the acetabular fracture ranged from 13 to 25 weeks, with a mean of 15.9 weeks, and the postoperative displacement of the acetabular fracture ranged from 0.6 to 5.2 mm, with a mean of 1.9 mm. Hip function was assessed at the final follow-up using a modified Merle D' Aubigné and Postel scale: there were 9 excellent, 11 good and 4 acceptable scores; an excellent rate of 83.3% was achieved. CONCLUSION: Patients with unstable pelvic fractures combined with acetabular fractures suffer severe trauma and complex mechanisms of injury. Treatment needs to be individualized, taking into account the patient's physiological status, fracture classification and degree of displacement.

Interfacial water engineering boosts neutral water reduction.

Hydrogen evolution reaction (HER) in neutral media is of great practical importance for sustainable hydrogen production, but generally suffers from low activities, the cause of which has been a puzzle yet to be solved. Herein, by investigating the synergy between Ru single atoms (RuNC) and RuSex cluster compounds (RuSex) for HER using ab initio molecular dynamics, operando X-ray absorption spectroscopy, and operando surface-enhanced infrared absorption spectroscopy, we establish that the interfacial water governs neutral HER. The rigid interfacial water layer in neutral media would inhibit the transport of H2O*/OH* at the electrode/electrolyte interface of RuNC, but the RuSex can promote H2O*/OH* transport to increase the number of available H2O* on RuNC by disordering the interfacial water network. With the synergy of RuSex and RuNC, the resulting neutral HER performance in terms of mass-specific activity is 6.7 times higher than that of 20 wt.% Pt/C at overpotential of 100 mV.

IGH V3-23*01 and its allele V3-23*03 differ in their capacity to form the canonical human antibody combining site specific for the capsular polysaccharide of Haemophilus influenzae type b.

The IGH V3-23*01 gene is used in the formation of the canonical combining site which dominates the human antibody repertoire to the Haemophilus influenzae type b (Hib) polysaccharide (PS). An allele of the human IGH V3-23*01 gene, known as V3-23*03, differs from V3-23*01 in nine bases, eight of which are located in the second complementarity determining region. These eight differences encode five amino acid substitutions. In this study we investigated whether the V3-23*03 sequence polymorphism affected Hib PS binding. We constructed two Fab fragments that had the canonical Hib PS combining site VH-VL configuration but that had either V3-23*01 or V3-23*03. Radioantigen binding assay showed that on a concentration basis the V3-23*03 Fab was 20-fold more effective in binding Hib PS than the V3-23*01 Fab. The V3-23*03 Fab was 4-fold more effective than the V3-23*01 Fab in mediating facilitated bactericidal activity against Hib organisms. These findings identify a functional consequence of V3-23 allelism, and suggest that utilization of the V3-23*03 gene in the human Hib PS repertoire would generate canonical antibodies with higher affinity and protective efficacy than canonical antibodies utilizing V3-23*01. Thus, IGH V gene allelic variation has the potential to impact the generation of protective immunity to Hib.