How does magnetically controlled growing rods insertion affect sagittal alignment in ambulatory early onset scoliosis patients?

PURPOSE: The importance of sagittal alignment restoration in early onset scoliosis (EOS) management has rarely been investigated to date. The aim was to report the influence of magnetically controlled growing rods (MCGR) insertion on the sagittal alignment of EOS patients. METHODS: All consecutive ambulatory patients operated with MCGR rods between 2011 and 2018 were retrospectively included in four institutions. Standing biplanar radiographs were performed preoperatively, in the early postoperative period and at latest follow-up. Global and local sagittal parameters, spinal global shape and harmony were investigated. RESULTS: A total of 37 ambulatory EOS patients were included (mean age at surgery 8.5 (± 2) years). 70% had a balanced construct postoperatively. Both MaxTK (- 17°, p = 0.02) and MaxLL (- 15°, p = 0.001) were significantly reduced, particularly at the instrumented levels. The number of vertebrae included in the lumbar lordosis significantly increased (+ 2 levels, p = 0.02), as well as the thoraco-lumbar inflexion point (+ 2 levels, p < 0.001) and the kyphosis apex (+ 1 level, p < 0.001). Overall mechanical failure rate was 40.5%, and radiological PJK was observed in 43% of the patients, with 11 remaining asymptomatic. Patients with initial hyperkyphosis (> 50°) developed more complications (62% vs. 28%, p = 0.04). CONCLUSION: MCGR insertion flattened the spine in EOS, at both instrumented and non-instrumented levels. Overall spinal harmony was modified, with a cranial shift of the thoraco-lumbar inflexion point and the thoracic kyphosis apex, associated with a lengthening of the lumbar lordosis. The rate of complication remained high, some explanations being found in the radiological changes reported such as the preoperative location of the TK apex. LEVEL OF EVIDENCE: IV.

Does the use of intrawound povidone-iodine irrigation and local vancomycin powder impact surgical site infection rate in adolescent idiopathic scoliosis surgery?

PURPOSE: Surgical site infection (SSI) is a major complication after adolescent idiopathic scoliosis (AIS) surgery, with an incidence ranging from 0.5 to 7%. Intraoperative wound decontamination with povidone-iodine (PVP-I) irrigation and/or vancomycin powder in adult spinal surgery has gained attention in the literature with controversial results. The aim of this study was to investigate the impact of using intrawound PVP-I irrigation and local vancomycin powder (LVP) on the incidence of early SSI in AIS surgery. METHODS: All AIS patients who underwent posterior spinal fusion between October 2016 and December 2019 were retrospectively reviewed. The incidence of early SSI was reported and compared between 2 groups defined by the treating spinal surgeons' preferences: group 1-intrawound irrigation with 2L of PVP-I and application of 3 g LVP before closure and control group 2-patients that did not receive either of these measures. RESULTS: Nine early cases of SSI (2.9%) were reported among the 307 AIS posterior spinal fusion patients. Incidence of SSI in group 1 (2/178 = 1.1%) was significantly lower than in group 2 (7/129 = 5.4%; p = 0.04). There were no adverse reactions to the use of PVP-I and LVP in our study. At latest follow-up, rate of surgical revision for mechanical failure with pseudarthrosis was significantly lower in group 1 (2/178 = 1.1%) than in group 2 (9/129 = 7.0%; p = 0.01). CONCLUSION: Intraoperative use of intrawound PVP-I irrigation and vancomycin powder is associated with a significant reduction of early SSI after AIS spine surgery. LEVEL OF EVIDENCE IV: Retrospective study.

Halo-gravity traction followed by definitive fusion in severe early onset scoliosis: results of a trunk analysis based on biplanar 3D reconstructions.

PURPOSE: Definitive fusion can be considered in early onset scoliosis (EOS) around triradiate cartilage closure. Halo-gravity traction (HGT) is an old strategy that can help lengthen and balance the spine before fusion. The postoperative changes of the trunk have never been investigated to date with modern imaging. The goal of this study was to analyze the 3D radiological outcomes, and the associated pulmonary function, of a cohort of severe EOS patients treated by definitive posterior fusion prepared by HGT. METHODS: All consecutive EOS patients with severe (> 85°) and stiff (flexibility < 25%) curves, treated by HGT followed by posterior fusion, were followed. 3D radiological measurements and pulmonary function were assessed. RESULTS: Forty-nine EOS patients underwent fusion, with a mean follow-up of 4 years (± 1). Age at surgery averaged 13.5 years old. HGT protocol reached on average 41% of body weight. Mean preoperative 3D Cobb angle was 95° (± 10) and final correction averaged 68.4% after surgery. 3D T4T12 kyphosis was reduced after surgery (11°, p < 0.01), while the apical vertebral rotation was improved by 27.8% (p = 0.06). 3D thoracic volume increased after surgery (p = 0.02), with a 3D T1T12 height gain averaging 3.7 cm (± 2). Both parameters were significantly correlated with total lung capacity improvement. Seven complications (14.2%) were reported, and 5 patients (10.6%) underwent unplanned revision. CONCLUSION: HGT is a safe and efficient strategy to prepare posterior fusion in severe EOS patients. The 3D trunk analysis demonstrated significant postoperative gains in thoracic and spinal lengths, as well as in thoracic volume. LEVEL OF EVIDENCE: IV.

Surgically Treated Pediatric Hand and Fingers Palmar Wounds Caused by Metal Fences: Analysis Over a 5-Year Period.

BACKGROUND: Hand wounds are frequent in children (31% of hand injuries) and one possible mechanism responsible for profound laceration is metal fences while climbing. These injuries usually require a surgical look to explore soft-tissue damages, but the literature is poor regarding surgical findings and outcomes after this kind of traumatism. The aim of the study was therefore to report a consecutive series of hand and finger wounds caused by metal fences in children, focusing on surgical findings and potential complications. METHODS: All consecutive hand or finger deep wounds caused by metal fences treated between January 2013 and December 2018 were retrospectively reviewed. Inclusion criteria were age below 18 years and a minimum follow-up of 2 years. Complications and surgical revisions were analyzed. RESULTS: A total of 1265 patients were operated for hand or finger deep wounds during the study period, among which 74 were caused by metal fences. The mean age at surgery was 11.3±0.4 years, and the majority of patients were men (80%). Associated injuries were found in 55.4% of the patients including nerves (n=29) or tendons sections/disinsertion (n=6), and sheath (n=16) and pulleys (n=6) tearing. At a mean follow-up of 2.6±0.2 years, 12% of the patients required revision surgery for an irreducible flexion contracture secondary to a contractile scar and consisted of complete scar excision and zigzag flap. Additional tenoarthrolysis was required during the procedure, for 6 patients because of a persisting flexion contracture after excision. CONCLUSIONS: Metal fences surgical palmar wounds in children are impressive lesions by their extended skin damages. Serious associated lesions (collateral pedicle or flexor tendons) were found in 1 case of 3. However, these injuries are not benign and should be carefully monitored clinically during the first postoperative month to look for potential contractile scars that can require revision. LEVEL OF EVIDENCE: Level IV-retrospective cohort study.

Is Cutibacterium acnes early surgical site infection rate related to the duration of antibiotic prophylaxis in adolescent idiopathic scoliosis surgery?

PURPOSE: Cutibacterium acnes (C. acnes) is a gram-positive anaerobic bacillus located in pilosebaceous glands, usually responsible for late postoperative surgical site infections (SSI). A recent study performed in our institution highlighted an unexpected emergence of C. acnes early SSI. One potential explanation was the change of the perioperative antibioprophylaxis (ATB) protocol, which switched from 48 h postoperative cefamandole to intraoperative only cefazoline. The aim of this study was therefore to investigate the influence of the ATB duration on the occurrence of C. acnes early SSI, by comparing the incidence rates during 3 consecutive ATB protocols. METHODS: Between January 2007 and September 2017, all patients who underwent posterior fusion for AIS were retrospectively reviewed. Early C. acnes SSI were reported and compared between 3 periods, during which the ATB protocols were modified. January 2007-February 2012: Intraoperative Cefamandole continued 48 h (protocol 1) March 2012-August 2016: Single shot of intraoperative Cefazoline (protocol 2) September 2016-September 2017: Intraoperative Cefazoline continued 48 h (protocol 3). RESULTS: Fifty-three early SSI (7.2%) were reported among the 732 posterior AIS fusions included. Global incidence of C. acnes infection was 2.9%. The incidence of C. acnes in early SSI increased from 0 to 4.9% between protocol 1 and 2, but was reduced to 1.7% with protocol 3. CONCLUSIONS: Early C acnes SSI can be explained by the difficulty to eradicate this pathogen with current skin preparation procedures and some Beta-lactam antibiotics tolerance. Longer duration antibioprophylaxis is preferable to prevent from early C. acnes SSI.

Correction to: Is Cutibacterium acnes early surgical site infection rate related to the duration of antibiotic prophylaxis in adolescent idiopathic scoliosis surgery?

Unfortunately, the authors first name and family name were incorrectly swapped in the original publication. The complete correct names of the author group is given below.

Enhanced recovery after surgical correction of adolescent idiopathic scoliosis.

BACKGROUND: Few publications in the literature examine enhanced recovery after scoliosis surgery (ERAS) in children, despite significant scientific interest in adults. The objective of the current study was to describe an ERAS protocol for surgical correction of adolescent idiopathic scoliosis (AIS) and its results. METHODS: ERAS outcomes were measured in two patient cohorts. Historical controls and ERAS groups were selected from patients managed for scoliosis surgery in 2015 and 2018, respectively. The ERAS protocol included fasting minimization, carbohydrate loading, the avoidance of background morphine infusions, perioperative opioid-sparing protocols, the use of a cooling brace, early physiotherapy, feeding and oral medications, and the early removal of urinary catheters and surgical drains. The main outcome of the study was hospital length of stay. RESULTS: Overall, 82 controls and 81 ERAS patients were recruited. ERAS protocols were observed in over 80% of patients for almost items. Median length of hospital stay was significantly lower in the ERAS group (- 3 [95% confidence interval: -2; -4] days). Median morphine consumption was reduced by 25% and 35% on days 2 and 3, respectively. The incidence of PONV did not differ between the two groups, and the incidence of constipation decreased slightly but significantly in the ERAS group on day 2. Pain intensity at rest and movement were lower in the ERAS group at day 2 and 3. CONCLUSIONS: The current study suggests an ERAS protocol after adolescent idiopathic scoliosis surgery is associated with reduced hospital length of stay and improved postoperative care.

Correction to: Efficacy of the Game Ready® cooling device on postoperative analgesia after scoliosis surgery in children.

Unfortunately, one co-author name was incorrectly published in the original publication. The complete correct name of the co-author is given below.

Efficacy of the Game Ready® cooling device on postoperative analgesia after scoliosis surgery in children.

PURPOSE: The aim of this study was to investigate the opioid-sparing effect of a cooling brace after surgical correction of idiopathic surgery in children. METHODS: We compared two consecutive cohorts of patients before and after introducing this technique in our institution. Management of patients was standardized. The primary objective of the study was to investigate the morphine consumption during the first postoperative day. Secondary outcomes were opioid consumption at day 3, pain intensity (at days 1 and 3), the mobilization in the standing position and duration of hospitalization. RESULTS: This study included 23 and 22 patients in the control and the cooling cohorts. Cooling brace was associated with a significant decrease in morphine consumption at day 1 (1.7 [0.9, 3.3] versus 1.2 [0.5, 3.2] mg kg-1, P = 0.02) and day 3 (2.5 [0.5, 6.7] versus 1.2 [0.9, 2.5] mg kg-1, P = 0.003), and a reduction in duration of hospitalization (4 [3, 6] versus 3 [3, 4] days, P = 0.004). However, no difference was found on the pain intensity or the percentage of patient mobilized in the standing position. Number of level fused and intraoperative opioid consumption were also different between the two cohorts. However, multivariate analysis found only the use of the cooling brace as significantly associated with opioid consumption at day 1. CONCLUSION: The use of this cooling brace allows decreasing the opioid use after surgical correction of idiopathic surgery in children. The current results strongly suggest an interest of this technique in the postoperative management of patients. These slides can be retrieved under Electronic Supplementary Material.

Long term results of the revisited Meary closing wedge tarsectomy for the treatment of the fixed cavo-varus foot in adolescent with Charcot-Marie-Tooth disease.

BACKGROUND: Various techniques have been proposed for the treatment of cavovarus feet (CVF). The aim of this study was to report outcomes of the revisited Meary's dorsal closing wedge tarsectomy for fixed CVF secondary to Charcot-Marie-Tooth (CMT) disease. METHODS: All CVF operated on between 1977 and 2011 were included. The tarsectomy design was modified from its original description and systemically combined with a plantar fascia release, a Dwyer osteotomy and a proximal extension osteotomy of the 1st metatarsal bone if required. Outcomes were assessed by 2 functional scores and radiographically. RESULTS: Among the 26 feet (20 patients), the Wicart and Seringe score was very good or good, fair and poor in respectively 58%, 23% and 19% of the feet. Hindfoot and midfoot AOFASs were of 95.5 and 75 respectively. All radiographic measures were significantly improved. CONCLUSIONS: This complete revisited procedure is an efficient and safe surgical technique for the treatment of the CMT disease CVF. LEVEL OF EVIDENCE: Level IV.

Temporal Association Between Rhinovirus Activity and Kingella kingae Osteoarticular Infections.

OBJECTIVE: To determine whether the seasonal distribution of Kingella kingae osteoarticular infections is similar to that of common respiratory viruses. STUDY DESIGN: Between October 2009 and September 2016, we extracted the results of K kingae-specific real-time polymerase chain reaction analyses performed for bone or joint specimens in patients from 2 pediatric tertiary care centers in Paris. We used data of respiratory virus detection from the Réseau National des Laboratoires network with coordination with the National Influenza Center of France. The Spearman rank correlation was used to assess a correlation between weekly distributions, with P < .05 denoting a significant correlation. RESULTS: During the 7-year study period, 322 children were diagnosed with K kingae osteoarticular infection, and 317 testing episodes were K kingae-negative. We observed high activity for both K kingae osteoarticular infection and human rhinovirus (HRV) during the fall (98 [30.4%] and 2401 [39.1%] cases, respectively) and low activity during summer (59 [18.3%] and 681 [11.1%] cases, respectively). Weekly distributions of K kingae osteoarticular infection and rhinovirus activity were significantly correlated (r = 0.30; P = .03). In contrast, no significant correlation was found between the weekly distribution of K kingae osteoarticular infection and other respiratory viruses (r = -0.17, P = .34 compared with respiratory syncytial virus; r = -0.13, P = .34 compared with influenza virus; and r = -0.22, P = .11 compared with metapneumovirus). CONCLUSION: A significant temporal association was observed between HRV circulation and K kingae osteoarticular infection, strengthening the hypothesis of a role of viral infections in the pathophysiology of K kingae invasive infection.

Stereoradiography imaging motion artifact: does it affect radiographic measures after spinal instrumentation?

PURPOSE: Stereoradiography imaging (SRI) is an accurate and reliable low-dose radiographic method. However, patients must remain motionless during image acquisition. Motion artifacts are frequently noted. The aims of the study were to determine the incidence of the SRI motion artifact and assess if motion during SRI acquisition affects radiographic measurements. METHODS: In this retrospective study, 198 patients with spinal instrumentation had biplanar SRI radiographs performed, of whom 39 had concomitant conventional radiographs. Eight coronal and sagittal spinal parameters were independently measured on SRI and conventional radiographs for the 39 patients by 2 observers. Inclusion criteria were: presence of spinal instrumentation of more than six levels and an SRI motion artifact identified on the coronal and/or the sagittal views on either the spinal rods or on the limbs. Means were compared between both types of radiographs using the Student's t test; intraclass correlation coefficients (ICCs) were used for intraobserver reproducibility and interrater reliability. RESULTS: A motion artifact was identified in 19.7 % (n = 39, mean age 19.5 ± 1.7 years) of the cases. There were no differences in any of the coronal or sagittal plane measurements between SRI and X-rays. Intraobserver reliability and interrater reproducibility was high (range 0.81-0.98). CONCLUSIONS: Motion artifact during full-spine stereoradiography imaging acquisition is frequent, but does not affect spinal measurements. SRI with a motion artifact can be used to produce reliable measurements of the sagittal and coronal parameters. Some SRI images with a motion artifact may suggest loss of fixation or bending of the rods. However, after becoming familiar with the appearance of the motion artifact, repeat radiographs are rarely indicated. IRB NUMBER: 14-004872. LEVEL OF EVIDENCE: Level IV.

Preliminary experience with SpineEOS, a new software for 3D planning in AIS surgery.

PURPOSE: Preoperative planning of scoliosis surgery is essential in the effective treatment of spine pathology. Thus, precontoured rods have been recently developed to avoid iatrogenic sagittal misalignment and rod breakage. Some specific issues exist in adolescent idiopathic scoliosis (AIS), such as a less distal lower instrumented level, a great variability in the location of inflection point (transition from lumbar lordosis to thoracic kyphosis), and sagittal correction is limited by both bone-implant interface. Since 2007, stereoradiographic imaging system is used and allows for 3D reconstructions. Therefore, a software was developed to perform preoperative 3D surgical planning and to provide rod's shape and length. The goal of this preliminary study was to assess the feasibility, reliability, and the clinical relevance of this new software. METHODS: Retrospective study on 47 AIS patients operated with the same surgical technique: posteromedial translation through posterior approach with lumbar screws and thoracic sublaminar bands. Pre- and postoperatively, 3D reconstructions were performed on stereoradiographic images (EOS system, Paris, France) and compared. Then, the software was used to plan the surgical correction and determine rod's shape and length. Simulated spine and rods were compared to postoperative real 3D reconstructions. 3D reconstructions and planning were performed by an independent observer. RESULTS: 3D simulations were performed on the 47 patients. No difference was found between the simulated model and the postoperative 3D reconstructions in terms of sagittal parameters. Postoperatively, 21% of LL were not within reference values. Postoperative SVA was 20 mm anterior in 2/3 of the cases. Postoperative rods were significantly longer than precontoured rods planned with the software (mean 10 mm). Inflection points were different on the rods used and the planned rods (2.3 levels on average). CONCLUSION: In this preliminary study, the software based on 3D stereoradiography low-dose system used to plan AIS surgery seems reliable for preoperative planning and precontoured rods. It is an interesting tool to improve surgeons' practice, since 3D planning is expected to reduce complications such as iatrogenic malalignment and to help for a better understanding of the complications, choosing the location of the transitional vertebra. However, further work is needed to improve thoracic kyphosis planning. These slides can be retrieved under Electronic Supplementary Material.

Does Staphylococcus aureus nasal decontamination affect the rate of early surgical site infection in adolescent idiopathic scoliosis surgery?

PURPOSE: Surgical site infection (SSI) is a main complication after adolescent idiopathic scoliosis (AIS) surgery. Nasal colonization with S. aureus is a known risk factor for developing nosocomial infections in cardiac surgery. However, the risk in orthopedic surgery remains unclear, especially in spine surgery. This study aims to report the efficacy of a preoperative nasal decontamination program in S. aureus carriers on the incidence of early SSI after AIS posterior surgery. METHODS: Between January 2014 and July 2017, all AIS patients were screened preoperatively with nasal swabs and decontaminated if positive 5 days before surgery. Early SSI was identified, and microorganisms findings were analyzed within nasal carriage and compared to a previous series published before the decontamination program (2007-2011). RESULTS: Among the 331 AIS posterior fusion performed during the study period, incidence of positive nasal swab was 23% (n = 75). Those were preoperatively decontaminated. In comparison with the period before the nasal decontamination program, incidence of S. aureus early SSI significantly decreased from 5.1 to 1.3%, p < 0.05. None of those S. aureus decontaminated patients had an early S. aureus SSI. In all cases of S. aureus infections, S. aureus nasal screening was negative with a mean delay of 315 days (± 115) before surgery, which was significantly different from the global cohort (104 days ± 67, p < 0.05). CONCLUSIONS: Preoperative S. aureus nasal decontamination was associated with a significant decrease in S. aureus SSI. Optimal delay of nasal screening needs to be optimized in order to diagnose intermittent S. aureus carriers. These slides can be retrieved under Electronic Supplementary Material.

Pulseless supracondylar humeral fractures in children: vascular complications in a ten year series.

PURPOSE: The management of pulseless supracondylar fractures remains controversial. The aims of this study were to: (1) analyse functional and vascular outcomes of conservative treatment for cases with absent pulse before reduction, whether patients showed limb ischaemia or not; and (2) identify factors associated with vascular complications. METHODS: Twenty-seven children with absent pulses on presentation were treated consecutively between 1999 and 2009. The brachial artery was surgically explored in cases of persistent signs of ischaemia after reduction. Signs of vascular impairment were recorded in the early post-operative period and at a mean final follow-up of 3.5 years. RESULTS: Recurrent ischaemia with a compartment syndrome occurred in a patient with initial ischaemia and a pink, pulseless hand after reduction. Patients with an initially well-perfused hand and those with pre-operative ischaemia and palpable pulses after reduction had satisfactory outcomes, as did patients with early arterial exploration. No patient showed signs of chronic vascular impairment. The need for vascular repair was significantly correlated with open fracture, initial ischaemia and nerve impairment. CONCLUSIONS: Conservative management of supracondylar fractures with absent pulses avoided long-term vascular complications provided that patients with a pulseless, well-perfused hand on presentation were closely monitored after reduction. Further study is necessary to determine whether a forearm Doppler would help identify children with absent pulses after reduction who need surgical revascularisation due to an insufficient collateral circulation.

Correction: Supramolecular influence on cis-trans isomerization probed by ion mobility spectrometry.

Correction for 'Supramolecular influence on cis-trans isomerization probed by ion mobility spectrometry' by Izabella Czerwinska et al., Phys. Chem. Chem. Phys., 2016, 18, 32331-32336.

Is There a Deficit After Nonoperative Versus Operative Treatment of Shortened Midshaft Clavicular Fractures in Adolescents?

BACKGROUND: Recent clinical studies in adults have reported a higher incidence of symptomatic malunions and functional deficits in nonoperatively treated shortened midshaft clavicular fractures. We sought to determine whether functional or subjective deficits are found in adolescents after operative versus nonoperative treatment of clavicle fractures. METHODS: Adolescents with displaced midshaft clavicle fractures, >15 mm of shortening, and a minimum of 9 months of follow-up were recruited. Exclusion criteria included concomitant upper extremity injuries or abnormalities that would affect biomechanical strength testing. Sixteen patients, equally divided between nonoperative and operative plate fixation, met inclusion criteria and consented to testing. The average age (±SD) at the time of injury was 14±2 years (range, 10 to 16 y), time from injury was 22±10 months (range, 10 to 41 mo), and shortening was 24±6 mm (range, 16 to 35 mm). Consenting subjects completed a QuickDASH Score, Constant Shoulder Score, and questions regarding satisfaction with treatment. Quantitative isometric strength, range of motion, and abduction fatigue testing was performed on the involved and uninvolved sides for comparison. RESULTS: Treatment groups did not differ in age, time from injury, or fracture shortening. QuickDASH and Constant Shoulder Scores were perfect in all but 1 patient in the operative group who actively complained of persistent symptomatic hardware. This patient and one other in the operative group underwent symptomatic hardware removal. There were no cases of symptomatic malunions in the nonoperative group. All patients expressed satisfaction with their treatment. Two in each treatment group were unsatisfied with the appearance of the clavicle. With the exception of a 3% decrease in abduction strength in the operative group (P=0.03) there were no differences in range of motion, isometric strength, or abduction fatigue of the involved shoulder in either treatment group. CONCLUSIONS: Shortened midshaft clavicular fractures had excellent outcomes after both operative and nonoperative treatments. No subjective or objective differences were observed between treatment groups. LEVEL OF EVIDENCE: Level III-therapeutic, retrospective comparative study.

The structure of chromophore-grafted amyloid-ß(12-28) dimers in the gas-phase: FRET-experiment guided modelling.

We present theoretical modelling, ion mobility spectrometry and action-FRET experiments for chromophore-grafted amyloid-ß(12-28) dimers. A first-principles global minimum search based on replica-exchange molecular dynamics (REMD) leads to a compact structure with strong interstrand interactions. We use REMD with a distance restraint that implements an adaptive effective bias upon average FRET-efficiencies and thus guides the sampling by the action-FRET measurement. This procedure leads to a pair of weakly interacting peptides. Ion-mobility confirms that the weakly interacting structure and not the global minimum with strongly interacting peptides is populated in the experiment. The presence of a high energy barrier between the two structural families, as evidenced from the MD data, suggests that a kinetically trapped structure is observed in the experiment.

Supramolecular influence on cis-trans isomerization probed by ion mobility spectrometry.

We used tandem ion mobility spectrometry measurements to investigate how the photo-isomerization of a chromophore (a methylpyridinium derivative) is affected by the complexation with a crown ether. A dramatic blue-shift of the photo-isomerization spectrum was observed upon complexation, which could be well reproduced by ab initio calculations. Our results support that the observed changes in the photo-physical properties of the chromophore originate from the charge-solvation of its pyridinium moiety by the host cage.

Chirality-dependent structuration of protonated or sodiated polyphenylalanines: IRMPD and ion mobility studies.

Ion mobility experiments are combined with Infra-Red Multiple Photon Dissociation (IRMPD) spectroscopy and quantum chemical calculations for assessing the role of chirality in the structure of protonated and sodiated di- or tetra-peptides. Sodiated systems show a strong chirality dependence of the competition between Na(+)O and Na(+)π interactions. Chirality effects are more subtle in protonated systems and manifest themselves by differences in the secondary interactions such hydrogen bonds between neutral groups or those involving the aromatic rings.