16-year outcomes of blunt thoracic aortic injury treated with thoracic endovascular aortic repair: A single-institution experience.

BACKGROUND: Blunt thoracic aortic injury (BTAI) is associated with considerable mortality and morbidity. Thoracic endovascular aortic repair (TEVAR) has essentially replaced open aortic repair (OAR) with superior outcome. The objective of this study was to evaluate the early and intermediate-term outcomes in patients sustaining BTAI treated with TEVAR, and to evaluate the prevalence and impact of left subclavian artery (LSA) coverage. METHODS: This retrospective analysis includes patients undergoing TEVAR for BTAI between February 2006 and December 2022 at the Helsinki University Hospital, Finland. The primary endpoints were 30-day and 2-year mortality, technical success of stent-graft system deployment, and procedural and device-related complications. The secondary endpoints pertained to reintervention events: conversion to OAR, re-TEVAR, any endovascular/surgical reinterventions for optimal stent-graft function, or any reinterventions during follow-up. RESULTS: A total of 38 consecutive BTAI patients treated with TEVAR were included in the analyses. Median patient age was 45.5 years (range, 15-79) and 66% were male. The median follow-up period was 39 months. Technical success was 100%, 30-day mortality was 0%, and 2-year mortality was 11% in the study cohort. Coverage of LSA without revascularization (13/18) resulted in one postoperative nondisabling stroke (1/13), no paraplegia, and one had ischemic left arm findings (1/13). Only one patient required reintervention (LSA embolization; 1/38). CONCLUSION: In this institutional series, we provide further evidence in favor of TEVAR for BTAI treatment. We demonstrated that TEVAR is linked to highly favorable outcomes in the short and intermediate term, and coverage of LSA without revascularization was quite well tolerated.

LIMPER trials: immediate mobilisation versus 2-week cast immobilisation after distal radius fracture treated with volar locking plate - a study protocol for a prospective, randomised, controlled trial.

INTRODUCTION: Open reduction and internal fixation with volar locking plate has become the most common fixation method in the treatment of unstable distal radius fracture (DRF). There is, however, no consensus as to whether or for how long a wrist should be immobilised after operative treatment. To date, there have been relatively few studies that have evaluated the effect of immediate postoperative mobilisation on functional outcomes. The aim of postoperative rehabilitation is to obtain a good function and to reduce impairment, recovery time, socioeconomical costs and absence from work. Therefore, there is a need for studies that evaluate the optimal method of postoperative rehabilitation to optimise wrist function and return to work. METHODS AND ANALYSIS: This study is a prospective, randomised, controlled trial in which a total of 240 working-age patients who undergo volar plating for DRF will be randomly assigned to either an early mobilisation group or a postoperative 2-week casting group. The aim of the study will be to compare early postoperative outcomes between the study groups. The primary outcome will be patient-rated wrist evaluation at 2 months after operation. A coprimary outcome will be the total length of sick leave. Our follow-up period will be 1 year, and secondary outcomes will include pain, patient satisfaction, perceived ability to work and complications identified at different time points. We expect those patients who undergo immediate mobilisation will have at least as rapid a return to work and function as those patients who undergo postoperative immobilisation, indicating/meaning that there will be no need for postoperative casting. ETHICS AND DISSEMINATION: This study will be conducted according to the Standard Protocol Items: Recommendations for Interventional Trials statement. The Ethics committee of Tampere University Hospital has approved the protocol. Ethics committee approval number is R21111, and it is accepted on 7 September 2021. The results of this study will be submitted for publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT05150925.

Peri-implant fracture: a rare complication after intramedullary fixation of trochanteric femoral fracture.

INTRODUCTION: Trochanteric femoral fractures are among the most common operatively treated fractures. Intramedullary fixation has become the treatment of choice in many centers around the world. Nevertheless, the knowledge of rare complications of these fractures is limited. In this study, the incidence and treatment strategies for peri-implant fractures (PIF) were assessed. MATERIALS AND METHODS: A single-center retrospective cohort study was done on 987 consecutive operatively treated trochanteric fractures. PFNA cephalomedullary nail was used as a fixation method. All patients were followed up from patient records for peri-implant fractures. Plain radiographs as well as different salvage methods were analyzed and compared. RESULTS: The total rate of peri-implant fractures was 1.4% (n = 14). The rate of PIF for patients treated with short (200 mm) nails, intermediate-length (240 mm) nails, and long nails was 2.7% (n = 2), 1.5% (n = 11), and 0.7% (n = 1), respectively (ns, p > 0.05 for difference). Treatment of choice for PIF was either ORIF with locking plate (57%, n = 8) or exchange nailing (43%, n = 6). None of the PIF patients needed additional surgeries for non-union, malunion, or delayed union. CONCLUSIONS: A PIF is a rare complication of intramedullary fixation of trochanteric fractures. It can be treated with either locking plates or exchange nailing with sufficient results. There are no grounds for favoring long nails to avoid PIFs.

Intramedullary Fixation of Trochanteric Fractures Can Be Safely Performed by Senior Residents Without Immediate Consultant Supervision.

OBJECTIVE: To assess the safety of senior residents performing trochanteric hip fracture surgery without immediate consultant supervision DESIGN: A retrospective chart review of trochanteric hip fractures (AO-OTA 31-A) operated in a single center between years 2011 and 2016 (inclusive). Operations were divided into three groups: Group 1 - surgeon was a senior resident without any immediate supervision; Group 2 - surgeon was a consultant and Group 3 - surgeon was a senior resident supervised by a consultant. The follow-up period was a minimum of 2 years or until death. All re-operations and surgical related mortality were assessed. SETTING: Helsinki University Hospital, Finland. A tertiary level trauma center. PARTICIPANTS: 987 consecutive trochanteric fractures on 966 patients treated by operative fixation of an intertrochanteric fracture with an intramedullary nail between 2011and 2016 (inclusive). RESULTS: The total number of reoperations was smaller in Group 1 where the surgeon was a senior resident without any immediate supervision compared to Group 2 where the surgeon was a consultant (5.5 % vs 8.8 %, p < 0.05). There were no significant differences in mortality or length of surgery. The total rate of mechanical complications was 2.0 %, with no significant differences between groups. The observed blade cut-out rate was low: 1.3 %, suggesting a good overall quality of surgery. CONCLUSIONS: Senior residents can safely perform intramedullary nailing of trochanteric fractures without immediate supervision.

Identifying volatile in vitro biomarkers for oral bacteria with proton-transfer-reaction mass spectrometry and gas chromatography-mass spectrometry.

We have measured the volatile fingerprints of four pathogenic oral bacteria connected to periodontal disease and dental abscess: Porphyromonas gingivalis (three separate strains), Prevotella intermedia, Prevotella nigrescens and Tannerella forsythia. Volatile fingerprints were measured in vitro from the headspace gas of the bacteria cultured on agar. Concrete identification of new and previously reported bacterial volatiles were performed by a combination of solid phase microextraction (SPME) and offline gas chromatography-mass spectrometry (GC-MS). We also studied the effect of the reduced electric field strength (E/N) on the fragmentation patterns of bacterial volatiles in online proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS). We aimed to discover possible new biomarkers for the studied oral bacteria, as well as to validate the combination of GC-MS and PTR-MS for volatile analysis. Some of the most promising compounds produced include: 1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ), indole, and a cascade of sulphur compounds, such as methanethiol, dimethyl disulphide (DMDS) and dimethyl trisulphide (DMTS). We also found that several compounds, especially alcohols, aldehydes and esters, fragment significantly with the PTR-MS method, when high E/N values are used. We conclude that the studied oral bacteria can be separated by their volatile fingerprints in vitro, which could have importance in clinical and laboratory environments. In addition, using softer ionization conditions can improve the performance of the PTR-MS method in the volatile analysis of certain compounds.

Infections after intramedullary fixation of trochanteric fractures are uncommon and implant removal is not usually needed.

BACKGROUND AND PURPOSE: Infections after intramedullary fixation of trochanteric femoral fractures are rare, but potentially life-threatening complications. There are limited data available to support decision making in these cases. PATIENTS AND METHODS: A retrospective study of 995 consecutive operatively treated trochanteric fractures was made to find out different risk factors for infection and to describe the results of treatment. RESULTS: 28 patients developed a surgical site infection (2.8%) after intramedullary fixation of trochanteric fracture. 15 patients (1.5%) had a deep and 13 patients (1.3%) a superficial surgical site infection. Cigarette smoking (p<0.05) and prolonged operative time (p<0.05) were significant risk factors for an infection. 15 of 28 patients needed revision surgeries. Implant removal or exchange was needed only for 4 of 28 patients: 1 exchange of the blade, 1 removal of additional cable used to assist reduction and 2 removals of distal locking screws. None of the patients needed additional surgeries for problems with fracture healing. Mortality was not increased among patients with an infection. INTERPRETATION: Infection after intramedullary fixation of trochanteric fractures can be successfully treated without removal or exchange of the fixation material.

Broadband Laser-Based Infrared Detector for Gas Chromatography.

Cantilever-enhanced photoacoustic spectroscopy coupled with gas chromatography is used to quantitatively analyze a mixture of alcohols in a quasi-online manner. A full identification and quantification of all analytes are achieved based on their spectral fingerprints using a widely tunable continuous-wave laser as a light source. This can be done even in the case of interfering column/septum bleed or simultaneously eluted peaks. The combination of photoacoustic spectroscopy and gas chromatography offers a viable solution for compact and portable instruments in applications that require straightforward analyses with no consumables.

Routine follow-up is unnecessary after intramedullary fixation of trochanteric femoral fractures-Analysis of 995 cases.

BACKGROUND AND PURPOSE: Approximately 2000 trochanteric fractures are operated in Finland annually. These fractures make a major burden to health care system and affected individuals. The role of routine follow-up has been questioned in multiple fracture types. PATIENTS AND METHODS: We analyzed routine follow-up visits after intramedullary fixation of trochanteric fractures (n = 995). Patients were followed up from patient registries until 2 years or death. Planned and unplanned follow-up visits were analyzed. RESULTS: Altogether 9 patients (0.9%) had a change in treatment at planned outpatient visit. 6 of these were due to mechanical complication, 1 due to refracture and 2 due to delayed unions. 64 (6.4%) patients had a change in treatment plan because of an unplanned visit: 28 infections, 6 pressure sores, 15 mechanic complications and 14 refractures and 1 AVN, respectively. INTERPRETATION: Routine follow-up visits are a burden both to the patients and health care system, with less than 1% leading to changes in treatment. Our suggestion is to give good instructions to patients and rehabilitation facilities instead of routine follow-up.

An Ab Initio Molecular Dynamics Study of the Hydrolysis Reaction of Sulfur Trioxide Catalyzed by a Formic Acid or Water Molecule.

Ab initio molecular dynamics (AIMD) calculations have been performed to investigate the role of dynamical and steric effects in formic acid (FA) or H2O-catalyzed gas phase hydrolysis of SO3 to form sulfuric acid. This was done by colliding FA or H2O with the SO3-H2O complex and the water dimer with the SO3 molecule and analyzing the outcomes of 230 AIMD trajectories. Our calculations show that, within simulation times used, sulfuric acid is formed in 5% of FA collisions but is not produced when H2O collides with the SO3-H2O complex or when the water dimer collides with the SO3 molecule. We also find that FA collisions have about 2 times higher probability to form the prereactive complex than H2O collisions. Moreover, our simulations show that the SO3-H2O-FA prereactive complex is more stable in time than the SO3-H2O-H2O prereactive complex. These findings indicate that the FA-catalyzed mechanism is favored over the H2O one when looking from the steric and dynamic effect point of view. Additionally, AIMD simulations starting from the optimized structure of the SO3-H2O-FA prereactive complex have been computed to qualitatively estimate the rate of the sulfuric acid formation. Collisional energy has been observed to promote sulfuric acid formation more effectively than thermal excitation.

On-line profiling of volatile compounds produced in vitro by pathogenic oral bacteria.

Infections by oral pathogens are one of the most common health problems worldwide. Due to the intimate connection between exhaled breath and the oral cavity, breath analysis could potentially be used to diagnose these infections. However, little is known about the volatile emissions of important oral pathogens that are connected with gingivitis and periodontitis. In this study, we have performed in vitro headspace measurements on four important oral pathogens (P. gingivalis, T. forsythia, P. intermedia and P. nigrescens) using proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS). Some of the most abundant compounds produced by the bacteria include hydrogen sulphide, methanethiol, acetone, dimethylsulphide, isoprene, cyclopentanone and indole as tentatively assigned from the mass spectra. Several other abundant mass signals were recorded but the assignment of these is less certain. Some of the bacterial species can be separated from each other by the emitted volatile fingerprints. The results of this study can be used in potential development of a diagnostic breath test for oral infections. In addition, as several of the measured compounds are known to be toxic, the results point to an intriguing possibility of studying the connection between the bacterial virulence and the emitted volatile compounds.

Ab Initio Molecular Dynamics Simulations of the Influence of Lithium Bromide Salt on the Deprotonation of Formic Acid in Aqueous Solution.

The deprotonation of formic acid is investigated using metadynamics in tandem with Born-Oppenheimer molecular dynamics simulations. We compare our findings for formic acid in pure water with previous studies before examining formic acid in aqueous solutions of lithium bromide. We carefully consider different definitions for the collective variable(s) used to drive the metadynamics, emphasizing that the variables used must include all of the possible reactive atoms in the system, in this case carboxylate oxygens and water hydrogens. This ensures that all the various possible proton exchange events can be accommodated and the collective variable(s) can distinguish the protonated and deprotonated states, even over rather long ab initio simulation runs (ca. 200-300 ps). Our findings show that the formic acid deprotonation barrier and the free energy of the deprotonated state are higher in concentrated lithium bromide, in agreement with the available experimental data for acids in salt solution. We show that the presence of Br- in proximity to the formic acid hydroxyl group effectively inhibits deprotonation. Our study extends previous work on acid deprotonation in pure water and at air-water interfaces to more complex multicomponent systems of importance in atmospheric and marine chemistry.

Broadband photoacoustic spectroscopy of CH414 with a high-power mid-infrared optical frequency comb.

We report a photoacoustic spectroscopy setup with a high-power mid-infrared frequency comb as the light source. The setup is used in broadband spectroscopy of radiocarbon methane. Owing to the high sensitivity of a cantilever-enhanced photoacoustic cell and the high-power light source, we can reach a detection limit below 100 ppb in a broadband measurement with a sample volume of only a few milliliters. The first infrared spectrum of CH414 is reported and given a preliminary assignment. The results lay a foundation for the development of optical detection systems for radiocarbon methane.

Cavity-enhanced cantilever-enhanced photo-acoustic spectroscopy.

We have improved the sensitivity of a state-of-the-art cantilever-enhanced photo-acoustic trace gas sensor by combining it with an optical power build-up cavity. The build-up cavity enhances the photo-acoustic signal by a factor of ∼100, resulting in an exceptionally good normalised noise equivalent absorption (NNEA) value of 1.75 × 10-12 W cm-1 Hz-1/2. We demonstrate the sensor platform in the 1530 nm wavelength range with a simple distributed feedback diode laser, achieving 75 ppt sensitivity for C2H2 with a 10 s integration time.

Ab Initio Molecular Dynamics Simulations of the Influence of Lithium Bromide on the Structure of the Aqueous Solution-Air Interface.

We present the results of ab initio molecular dynamics simulations of the solution-air interface of aqueous lithium bromide (LiBr). We find that, in agreement with the experimental data and previous simulation results with empirical polarizable force field models, Br- anions prefer to accumulate just below the first molecular water layer near the interface, whereas Li+ cations remain deeply buried several molecular layers from the interface, even at very high concentration. The separation of ions has a profound effect on the average orientation of water molecules in the vicinity of the interface. We also find that the hydration number of Li+ cations in the center of the slab Nc,Li+-H2O ≈ 4.7 ± 0.3, regardless of the salt concentration. This estimate is consistent with the recent experimental neutron scattering data, confirming that results from nonpolarizable empirical models, which consistently predict tetrahedral coordination of Li+ to four solvent molecules, are incorrect. Consequently, disruption of the hydrogen bond network caused by Li+ may be overestimated in nonpolarizable empirical models. Overall, our results suggest that empirical models, in particular nonpolarizable models, may not capture all of the properties of the solution-air interface necessary to fully understand the interfacial chemistry.

Step-modulated decay cavity ring-down detection for double resonance spectroscopy.

A method of measuring double resonant two-photon signal and background from a single cavity ring-down decay is introduced. This is achieved by modulating the double resonance loss via one of the light sources exciting the transition. The noise performance of the method is characterized theoretically and experimentally. The addition of a new parameter to the fitting function introduces a minor noise increase due to parameter correlation. However, the concurrent recording of the background can extend the stable measurement time. Alternatively, the method allows a faster measurement speed, while still recording the background, which is often advantageous in double resonance measurements. Finally, the method is insensitive to changes in the cavity decay rate at short timescales and can lead to improved performance if they have significant contribution to the final noise level compared to the detector noise.

Ab initio molecular dynamics studies of formic acid dimer colliding with liquid water.

Ab initio molecular dynamics simulations of formic acid (FA) dimer colliding with liquid water at 300 K have been performed using density functional theory. The two energetically lowest FA dimer isomers were collided with a water slab at thermal and high kinetic energies up to 68kBT. Our simulations agree with recent experimental observations of nearly a complete uptake of gas-phase FA dimer: the calculated average kinetic energy of the dimers immediately after collision is 5 ± 4% of the incoming kinetic energy, which compares well with the experimental value of 10%. Simulations support the experimental observation of no delayed desorption of FA dimers following initial adsorption. Our analysis shows that the FA dimer forms hydrogen bonds with surface water molecules, where the hydrogen bond order depends on the dimer structure, such that the most stable isomer possesses fewer FA-water hydrogen bonds than the higher energy isomer. Nevertheless, even the most stable isomer can attach to the surface through one hydrogen bond despite its reduced hydrophilicity. Our simulations further show that the probability of FA dimer dissociation is increased by high collision energies, the dimer undergoes isomerization from the higher energy to the lowest energy isomer, and concerted double-proton transfer occurs between the FA monomers. Interestingly, proton transfer appears to be driven by the release of energy arising from such isomerization, which stimulates those internal vibrational degrees of freedom that overcome the barrier of a proton transfer.

Sub-parts-per-trillion level sensitivity in trace gas detection by cantilever-enhanced photo-acoustic spectroscopy.

An exceptional property of photo-acoustic spectroscopy is the zero-background in wavelength modulation configuration while the signal varies linearly as a function of absorbed laser power. Here, we make use of this property by combining a highly sensitive cantilever-enhanced photo-acoustic detector, a particularly stable high-power narrow-linewidth mid-infrared continuous-wave optical parametric oscillator, and a strong absorption cross-section of hydrogen fluoride to demonstrate the ability of cantilever-enhanced photo-acoustic spectroscopy to reach sub-parts-per-trillion level sensitivity in trace gas detection. The high stability of the experimental setup allows long averaging times. A noise equivalent concentration of 650 parts-per-quadrillion is reached in 32 minutes.

Reduction of FENO by tap water and carbonated water mouthwashes: magnitude and time course.

Fractional exhaled nitric oxide (FENO) assesses eosinophilic inflammation of the airways, but FENO values are also influenced by oral nitric oxide (NO). The aim of this pilot study was to measure FENO and compare the effect of two different mouthwashes on FENO and analyse the duration of the effect. FENO was measured in 12 randomized volunteers (healthy or asthmatic subjects) with a NIOX VERO® analyser at an expiratory flow rate of 50 mL/s. After a baseline measurement, a mouthwash was performed either with tap water or carbonated water and was measured during 20 min in 2 min intervals. The procedure was repeated with the other mouthwash. We found that both mouthwashes reduced FENO immediately at the beginning compared to the baseline (p < .001). The carbonated water mouthwash effect lasted 12 min (p ranging from <0.001 to <0.05). The tap water mouthwash reduced FENO statistically significantly only for 2 min compared with the baseline. We conclude that a single carbonated water mouthwash can significantly reduce the oropharyngeal NO contribution during a 12 min time interval.

Stabilization of femtosecond optical parametric oscillators for infrared frequency comb generation.

A synchronously pumped optical parametric oscillator (SP-OPO) is one of the most common techniques to generate femtosecond frequency combs in the mid-infrared region. Stable long-term operation of an SP-OPO requires active locking of the OPO resonator round-trip time to the pump pulse interval. A simple modulation-free locking method based on stabilization of narrow-band frequency-doubled power of the SP-OPO output comb is demonstrated in this Letter. The method relies on the strong dependency of frequency-doubled power on spectral shape of the comb, leading to better stability of the comb envelope spectrum than the commonly used dither-and-lock method.

Frequency comb assisted two-photon vibrational spectroscopy.

We report a setup for high-resolution two-photon spectroscopy using a mid-infrared continuous wave optical parametric oscillator (CW-OPO) and a near-infrared diode laser as the excitation sources, both of which are locked to fully stabilized optical frequency combs. The diode laser is directly locked to a commercial near-infrared optical frequency comb using an optical phase-locked loop. The near-infrared frequency comb is also used to synchronously pump a degenerate femtosecond optical parametric oscillator to produce a fully stabilized mid-infrared frequency comb. The beat frequency between the mid-infrared comb and the CW-OPO is then stabilized through frequency locking. We used the setup to measure a double resonant two-photon transition to a symmetric vibrational state of acetylene with a sub-Doppler resolution and high signal-to-noise ratio.