Line Positions Research Articles

Analysis of Long-Distance Geometric Error Measurement and Uncertainty Based on PSD Laser Collimation Principle

Due to the limitations of traditional geometric error measurement, the measurement accuracy of long-stroke geometric errors is generally not high and the operation is complicated. In response to the above situation, in this study, a geometric error measurement system is built with a laser beam as the reference line and 2D position sensitive detector as the photoelectric conversion device. The single measurement range is 40 m, and the measurement range is further expanded through the principle of segmented splicing. Using an ultra-long guide rail as the measurement object for straightness measurement, the experimental results are similar to those of a laser interferometer. The uncertainty analysis model was obtained through the analysis of quantity characteristics, and based on this, the variance synthesis theorem and probability distribution propagation principle were studied to form two uncertainty synthesis methods. The measurement evaluation results showed that the two methods were basically consistent. The work provided a reference method for the uncertainty evaluation of position-sensitive detector measurement systems in the future.

Wavenumber Calibration Protocol for Raman Spectrometers Using Physical Modelling and a Fast Search Algorithm.

A wavenumber calibration protocol is proposed that replaces polynomial fitting to relate the detector axis and the wavenumber shift. The physical model of the Raman spectrometer is used to derive a mathematical expression relating the detector plane to the wavenumber shift, in terms of the system parameters including the spectrograph focal length, the grating angle, and the laser wavelength; the model is general to both reflection and transmission gratings. A fast search algorithm detects the set of parameters that best explains the position of spectral lines recorded on the detector for a known reference standard. Using three different reference standards, four different systems, and hundreds of spectra recorded with a rotating grating, we demonstrate the superior accuracy of the technique, especially in bands outside of the outermost reference peaks when compared with polynomial fitting. We also provide a thorough review of wavenumber calibration for Raman spectroscopy and we introduce several new evaluation metrics to this field borrowed from chemometrics, including leave-one-out and leave-half-out cross-validation.

Jet-cooled ethylene cavity ring-down spectroscopy between 5880 and 6200 cm−1

Absorption spectra of jet-cooled ethylene (ethene, C2H4) are recorded at three different rotational temperatures (6/8 K, 12 K, 38 K) using cavity ring-down spectroscopy (CRDS) in the 5880–6200 cm−1 spectral region. Rotational cooling is used to determine the various vibrational band centers by simplifying drastically the rotational band structure. A line-by-line assignment, based on a direct comparison with the TheoReTS variational line list and a systematic use of lower state combination difference (LSCD), is performed. Experimental line lists including line position and line integrated absorption cross sections are drawn up. The 6/8 K, 12 K and 38 K spectra contain 668, 1553 and 1679 absorption lines respectively. Overall, 320 rovibrational lines are assigned across 20 interacting vibrational bands. Among the 20 vibrational cold bands identified in this work, 14 had never been observed before. Line intensities are in the range of 10−24 - 10−20 cm/molecule. A direct comparison between our work and the TheoReTS and ExoMol theoretical line lists, as well as with the recent experimental work of Ben Fathallah et al. (2024) is provided.

Pediatric Supracondylar Humerus Fractures: Treatment by a Pediatric Orthopedic Surgeon Versus a Non-pediatric Orthopedic Surgeon.

Supracondylar humerus fractures are the most common surgically treated fracture in children. National trends have demonstrated an increase in transfers of supracondylar fractures to pediatric hospitals due to the perception that supracondylar fractures need to be treated by pediatric specialists. The objectives of the study are to compare the outcomes of surgically treated pediatric supracondylar humerus fractures (PSCHF) between a pediatric orthopedic surgeon and a non-pediatric orthopedic surgeon at a single academic medical center; to assess radiographic reduction, the number of pins used, surgical time, Flynn criteria outcomes, and complications associated with PSCHF treatment by both types of surgeons; to determine if there is a significant difference in outcomes between pediatric and non-pediatric orthopedic surgeons in the treatment of PSCHF. Forty-seven consecutive pediatric patients, with an average age of 5.5 years old, who had undergone surgical correction for supracondylar humerus fractures during 2019 were included in this study. The intervention performed was closed reduction and percutaneous pinning. The main outcome measured: radiographic reduction on the AP and lateral X-ray view, number of K wires used, use of a medial K wire, time of surgery, the Flynn criteria, and complications. The Human Research Protection Program (HRPP) at Penn State approval was obtained. Radiographic reductions as measured by Bauman's angle and the position of the anterior humeral line were excellent and similar between surgeons. The pediatric orthopedic surgeon used more medial K wires (p=0.0007), fewer K wires (p=0.0065), and the length of surgery was shorter (p=0.019). The Flynn criteria were similar with equal excellent and good results. For both surgeons, no complications such as loss of reduction, infection, iatrogenic nerve injury, compartment syndrome, or cubitus varus occurred. Outcomes of treatment of displaced PSCHF by the pediatric and non-pediatric orthopedic surgeons were equal. The results of this study reaffirm the assertion that both pediatric and non-pediatric orthopedic surgeons have sufficient training and skill to treat these common fractures, thereby contributing to a more informed decision-making process in clinical practice.

Morphological features of the acetabulum with coxa profunda in women: a retrospective observational study

BackgroundThe morphology of coxa profunda remains inadequately understood. However, knowledge about the characteristics of the acetabulum in coxa profunda can help to predict pelvic morphology in three dimensions based on radiographic findings, as well as help to diagnose and predict hip pathologies. Therefore, this study aimed to investigate the relationship between the morphological characteristics of the pelvis and coxa profunda.MethodsWe conducted a retrospective analysis including women who had undergone unilateral total hip arthroplasty. Only those with normal hip joint morphology on the opposite side, as evidenced by anteroposterior pelvic radiography showing a distance of ≥ 2 mm between the ilioischial line and acetabular floor, were included. Five parameters related to acetabular anteversion, thickness, and the position of the ilioischial line were measured using axial computed tomography at the central hip joint. The coxa profunda group (n = 39) and control group (n = 34) were compared.ResultsThe mean acetabular anteversion angle was 12.5° ± 4° in the control group and 22.3° ± 5.6° in the coxa profunda group. The mean thickness from the acetabular fossa to the medial wall was 7.5 ± 1.7 mm in the control group and 3.9 ± 1.2 mm in the coxa profunda group. Furthermore, the bony region representing the ilioischial line was positioned more posteriorly in the coxa profunda group than it was in the control group.ConclusionOur findings suggest that coxa profunda in women is associated with anterior acetabular dysplasia and a thin acetabulum, in contrast to previous interpretations of excessive coverage. This insight suggests a conversion of coxa profunda from a finding of pincer-type femoroacetabular impingement to a finding of acetabular dysplasia, a revelation that also draws attention to cup positioning for total hip arthroplasty.

Imidazoline As a Volatile Corrosion Inhibitor for Mitigation of Top- and Bottom-of-the-Line CO2 Corrosion in Carbon Steel Pipelines.

A fatty acid imidazoline-based inhibitor was synthesized via a facile solvent-free synthesis method between tall oil fatty acid (TOFA) and diethylenetriamine (DETA) under atmospheric conditions with a short reaction time. The as-synthesized imidazoline (S-Imd) acted as an effective inhibitor for reducing or preventing corrosion of carbon steel pipelines at both bottom of the line (BOL) and top of the line (TOL) positions under simulated conditions of a gas pipeline in a CO2-saturated environment. The inhibition efficacy was examined by both weight loss and electrochemical measurements, such as the electrochemical impedance spectrum (EIS), potentiodynamic polarization (PDP), and linear polarization resistance (LPR). The results revealed that the S-Imd, 2-(8-heptadecenyl)-2-imidazoline-1-ethanamin, at 300 ppm exhibited a superior inhibition efficiency of up to 91.6 and 89.9% for BOL and TOL corrosion tests, respectively. The surface morphology of the carbon steel test specimens was also examined using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), and contact angle analysis. It was found that the as-synthesized S-Imd acted as a mixed-type inhibitor that exhibited a decreased surface roughness and oxide layer on carbon steel surfaces. However, the water contact angle was found to increase, implying enhanced hydrophobicity of the surface. Adsorption of the imidazoline molecules on carbon steel surfaces followed the Langmuir adsorption isotherm. The present work provides very promising results in the synthesis and utilization of the studied imidazoline as a volatile corrosion inhibitor (VCI), especially for carbon steel pipelines in petroleum industries.

Crisis and Mood: Waiting in Line for Gasoline During the 1979 Oil Shock in the United States

The topic of crisis remains relevant. During this study's writing and editing process, the COVID-19 coronavirus disease appeared on the world's stage. Further, it is uncanny that in the final stage of the study's 2021 publication, the United States Atlantic Seaboard experienced a gasoline shortage after a cyberattack disabled a major pipeline resulting in crisis lines at gas stations. The study compares the mood of drivers waiting in line for a necessity in a national crisis, in this case, gasoline, during the oil shock of 1979 in the United States to those not waiting shortly after the crisis ended. It also examines how position in such crisis lines affects mood. All subjects answered yes-no adjective questions for anxiety, hostility, and positive affect. Line position was determined by counting the number of cars from the pump. Those waiting showed more hostility, anxiety, positive affect, and uncertainty than those not in line. During the crisis, those farthest from the pump showed greater hostility and less positive affect than those closer, but no difference in anxiety, with uncertainty moderating positive affect but not anxiety or hostility. The crisis occurred at a time when smartphones did not exist. The results suggest smartphones during a crisis would probably have their most significant positive impact if used to reduce uncertainty in fulfilling consumer information needs. Crisis, by its nature, is an unpredictable phenomenon that may explain why there are far more studies of the routine lines encountered in daily living, such as those at airports or call centers, than those experienced in crisis.

Assistance force-line of exosuit affects ankle multidimensional motion: a theoretical and experimental study

BackgroundThe talocrural joint and the subtalar joint are the two major joints of the ankle-joint complex. The position and direction of the exosuit force line relative to these two joint axes can influence ankle motion. We aimed to understand the effects of different force-lines on ankle multidimensional motion.MethodsIn this article, three assistance force line schemes for ankle exosuits were proposed: perpendicular to the talocrural joint axis (PT), intersecting with the subtalar joint axis (IS), and parallel to the triceps surae (PTS). A theoretical model was proposed to calculate the exosuit’s assistance moment. Seven participants completed four experimental tests of ankle plantarflexion, including three passive motions assisted by the PT, PTS and IS schemes, and one active motion without exosuit assistance (Active).ResultsThe simulation results demonstrated that all three exosuits were able to produce significant moments of ankle plantarflexion. Among these, the PT scheme exhibited the highest moments in all dimensions, followed by the PTS and IS schemes. The experimental findings confirmed the effectiveness of all three exosuit schemes in assisting ankle plantarflexion. Additionally, as the assistive force lines approached the subtalar joint, there was a decrease in ankle motion assisted by the exosuits in non-plantarflexion directions, along with a reduction in the average distance of ankle angle curves relative to active ankle motion. Furthermore, the linear correlation coefficients between inversion and plantarflexion, adduction and plantarflexion, and adduction and inversion gradually converged toward active ankle plantarflexion motion.ConclusionsOur research indicates that the position of the exosuit force line to the subtalar joint has a significant impact on ankle inversion and adduction. Among all three schemes, the IS, which has the closest distance to the subtalar joint axes, has the greatest kinematic similarity to active ankle plantarflexion and might be a better choice for ankle assistance and rehabilitation.

Optimization of Multibeam Survey Measurement Based on Greedy Algorithm

The effectiveness of multibeam bathymetric technology is widely recognized in marine depth measurements, especially in areas with complex and variable seafloor topography. This study aims to design a multibeam bathymetric survey plan for a specific maritime region, with the objectives of minimizing the total survey line length, ensuring comprehensive coverage of the target area, controlling the overlap between adjacent survey lines, and fully considering variations in seafloor topography. An optimization model was developed to determine the optimal route for comprehensive seafloor depth measurements within the specified maritime area.The model initially considers the influence of seafloor slope, establishing a single optimization objective model with the goal of minimizing the total survey line length. The decision variables primarily include the spacing between adjacent survey lines. The objective function of the model aims to reduce the number of survey lines, thereby achieving the minimization of the total survey line length. Constraints of the model encompass limitations on coverage range, calculations of coverage width, and relationships between survey lines. The model is solved using a greedy algorithm-based optimization approach, iteratively updating the positions of survey lines while determining the spacing based on the relationship between depth and coverage width. Ultimately, a layout of survey lines with the shortest total length, totaling 64 nautical miles with a configuration of 32 survey lines, is obtained for the assumed maritime area. Multibeam bathymetric technology holds broad prospects in the field of marine measurements, particularly in areas characterized by complex and variable seafloor topography. This study, by designing a multibeam bathymetric survey plan for a specific maritime region, not only contributes to improving measurement efficiency and accuracy but also reduces measurement costs and resource consumption. The outcomes of this research have significant practical implications for marine resource development, seafloor engineering construction, environmental protection, providing professionals in related fields with an effective measurement method and optimization strategy.

Photoluminescence studies of the charge states of nitrogen vacancy centers in diamond after arsenic ion implantation and subsequent annealing

In this work, nitrogen vacancy (NV) centers of high nitrogen diamond implanted with arsenic ions were investigated by photoluminescence spectroscopy. The transition of the NV center charge state was discussed by the regularly changing laser excitation power and measurement temperature following high-temperature annealing. After high-temperature annealing, the amorphous layer generated by arsenic ion implantation is transformed into a graphitization layer, resulting in a decrease in the NV yield. The electric neutral NV (NV0) center and negatively charged NV (NV−) center are affected by both radiation recombination and Auger recombination with increasing laser power. Accompanied by the increasing measurement temperature, the intensities of NV centers gradually decreased and eventually quenched. In addition, the charge states of NV− and NV0 centers were undergoing a transition. The zero phonon line positions of NV centers were also red shift, it was attributed to the dominant role of electron–phonon interaction in the temperature-dependent displacement of diamond energy gaps. The full width at half maxima of NV center were broadened significantly at higher temperatures.

Research progress in the treatment of distal humeral metaphyseal-diaphyseal junction fracture in children

To summarize the research progress in the treatment of distal humeral metaphyseal-diaphyseal junction (DHMDJ) fractures in children and to provide reference for clinical practice. The characteristics and treatment methods of transverse and comminuted DHMDJ fractures in children were summarized and analyzed by referring to relevant literature at home and abroad. DHMDJ fractures in children are not uncommon clinically, with high fracture line position, multi-directional instability, difficult closed reduction in treatment, and easy to cause complications such as coronal and sagittal deformity of the elbow. The Kirschner wire technique was effective for DHMDJ fractures with the fracture line at the middle and low levels, but was prone to iatrogenic ulnar nerve injury. Elastic stable intramedullary nail is suitable for higher-position transverse DHMDJ fractures. However, this technique requires a second operation to remove the internal fixator, and may cause iatrogenic epiphysis plate injury in children. External fixator is a new way to treat DHMDJ fractures, and it can show satisfactory results for transverse and comminuted DHMDJ fractures. However, at present, there are few relevant studies, and most of them focus on biomechanical studies, and the efficacy lacks high-quality clinical research support. The ultimate goal of DHMDJ fracture treatment in children is to restore the anatomical alignment of the fracture and prevent the loss of reduction. The choice of internal fixator depends on the location of the fracture line and the shape of the fracture to provide personalized treatment.

A Foam Line Position Detection Algorithm for A/O Pool Based on YOLOv5

During the biochemical pretreatment process of leachate in urban landfill sites, if the foam in the A/O pool is not promptly addressed, it can lead to overflow, posing hazards to the surrounding environment and personnel. Therefore, a real-time foam line detection algorithm based on YOLOv5x was proposed, which enhances feature information and improves anchor box regression prediction to accurately detect the position of foam lines. Firstly, in the preprocessing stage, employing a rectangular box to simultaneously label the foam line and the edge of the A/O pool within the same region, enhances the feature information of the foam line. Then, the C3NAM module was proposed, which applies weight sparse penalties to attention modules in the feature extraction section, to enhance the capability of extracting foam line features. Subsequently, a B-SPPCSPC module was proposed to enhance the fusion of shallow and deep feature information, addressing the issue of susceptibility to background interference during foam line detection. Next, the Focal_EIOU was introduced to ameliorate the issue of class imbalance in detection, providing more accurate bounding box predictions. Lastly, optimizing the detection layer scale improves the detection performance for smaller targets. The experimental results demonstrate that the accuracy of this algorithm reaches 98.9%, and the recall reaches 88.1%, with a detection frame rate of 26.2 frames per second, which can meet the actual detection requirements of real-world application scenarios.

Accurate Infrared Line Lists for 20 Isotopologues of CS2 at Room Temperature

To facilitate atmospheric and spectroscopic studies of carbon disulfide, or CS2, in both planetary and exoplanetary atmospheres, we adopt the “Best Theory + Reliable High-resolution Experiment” algorithm to generate semiempirical IR line lists for the 20 most abundant CS2 isotopologues, denoted as Ames-296K. The IR lists are computed using the Ames-1 potential energy surface, refined using the experimental transition set and an ab initio dipole moment surface fitted from CCSD(T)/aug-cc-pV(T/Q/5+d)Z dipoles extrapolated to a one-particle basis set limit. The IR lists cover the range of 0–10,000 cm−1, with an S 296K cutoff at 10−31 cm−1/molecule·cm−2 (abundance included). A “natural” IR line list at 296 K includes about 10 million lines of the 20 isotopologues, with their intensities scaled by the corresponding abundances. The zero-point energy, partition functions, and abundances are reported for each isotopologue. The energy levels in the global effective Hamiltonian model for 12C32S2 are adopted to improve the line position accuracy. This new IR list for the main isotopologue is denoted as A+I.296K. Reliable HITRAN2020 line positions are also utilized to improve the accuracy of the 32S12C34S, 32S12C33S, and 32S13C32S isotopologue line lists. The final composite line list is validated against Pacific Northwest National Laboratory experimental cross sections, showing excellent agreement. The agreement supports the quality of the composite line list and the power of synergy between experiment and theory. The new data are proposed for use in updating and expanding the CS2 data in HITRAN and other high-resolution IR databases. Supplementary files are available in Zenodo and AHED.

A scapular statistical shape model can reliably predict premorbid glenoid morphology in conditions of severe glenoid bone loss

Knowledge of premorbid glenoid parameters at the time of shoulder arthroplasty, such as inclination, version, joint line position, height, and width, can assist with implant selection, implant positioning, metal augment sizing, and/or bone graft dimensions. The objective of this study was to validate a scapular statistical shape model (SSM) in predicting patient-specific glenoid morphology in scapulae with clinically relevant glenoid erosion patterns. Computed tomography scans of 30 healthy scapulae were obtained and used as the control group. Each scapula was then virtually eroded to create 7 erosion patterns (Walch A1, A2, B2, B3, D, Favard E2, and E3). This resulted in 210 uniquely eroded glenoid models, forming the eroded glenoid group. A scapular SSM, created from a different database of 85 healthy scapulae, was then applied to each eroded scapula to predict the premorbid glenoid morphology. The premorbid glenoid inclination, version, height, width, radius of best-fit sphere, and glenoid joint line position were automatically calculated for each of the 210 eroded glenoids. The mean values for all outcome variables were compared across all erosion types between the healthy, eroded, and SSM-predicted groups using a 2-way repeated measures analysis of variance. The SSM was able to predict the mean premorbid glenoid parameters of the eroded glenoids with a mean absolute difference of 3°±2° for inclination, 3°±2° for version, 2 ± 1 mm for glenoid height, 2 ± 1 mm for glenoid width, 5 ± 4 mm for radius of best-fit sphere, and 1 ± 1 mm for glenoid joint line. The mean SSM-predicted values for inclination, version, height, width, and radius were not significantly different than the control group (P>.05). An SSM has been developed that can reliably predict premorbid glenoid morphology and glenoid indices in patients with common glenoid erosion patterns. This technology can serve as a useful template to visually represent the premorbid healthy glenoid in patients with severe glenoid bony erosions. Knowledge of the premorbid glenoid preoperatively can assist with implant selection, positioning, and sizing.

Experimental Study on the Distribution Law of Wind Speed in Rectangular Section Tunnels of Coal Mines

Ventilation is the cornerstone of coal mine safety production, and accurate monitoring of ventilation parameters is the fundamental guarantee for ventilation technology decision-making. A calculation model for the average wind speed line position in rectangular section tunnels of coal mines was established based on the Boussinesk theory and Prandtl turbulence theory to address the issue of difficulty in meeting decision-making needs in wind speed monitoring accuracy. The airflow field of rectangular section tunnels under different wind speed conditions was measured at the coal mine site, and the average position of the measured average wind speed line was obtained. The comparison and verification with the theoretical calculation results were carried out, with an absolute error of less than 5%.

Position of Fovea Palatinae relative to the vibrating line in various soft palate classifications among Jordanian edentulous population

This study aims to examine the relationship between the locations of Fovea Palatinae and the posterior vibrating line in different classes of soft palate angulation (House Classification), accordingly determine its reliability as a landmark and a tool for determining the posterior limit of the maxillary complete denture. 280 completely edentulous patients with normal healthy mucosa from both genders were randomly selected. The House classification of the soft palate angulation was identified and recorded as Class I, II, or III. Phonation was used to determine the position of the vibrating line. The Fovea Palatinae was then marked. Then, the distance between the Fovea Palatinae and the vibrating line was measured and recorded. Finally, the relative position of the Fovea Palatinae to the vibrating line was recorded as being anterior, posterior, or on the vibrating line. The Chi Square test, the effect size measures (Eta and Cramer’s V tests), The Spearman’s Rho rank correlation test, and multinominal logistic regression analysis were utilized to analyse the data. House classification percentages were measured among people whose Fovea Palatinae was detectable; Class II palate was the most prevalent (47.14%), followed by Class I (43.93%), and then Class III (8.93%). Based on vibrating line position, 129 (58%) had a vibrating line anterior to Fovea Palatinae, 57 (26%) on the Fovea Palatinae, 36 (16%) posterior to Fovea Palatinae, and in 58 (21%) Fovea Palatinae were not detected. The mean distance between the vibrating line and Fovea Palatinae was 3.66 ± 1.6 mm anteriorly and 2.97 ± 1.36 mm posteriorly. No significant differences were found between males and females in regard to House classification and vibrating line position. The odds of having the fovea posterior to the vibrating line would increase by 5% for each year increase in the age (P = 0.035, odds ratio = 1.050). Class II House classification of the soft palate was found to be the most prevalent among the study participants. Also, the vibrating line was anterior to the Fovea Palatinae in the majority of cases. The odds of having the fovea posterior to the vibrating line would increase by age. The Fovea Palatinae could be considered a useful guide for locating the vibrating line.

Spectroflat: A generic spectrum and flat-field calibration library for spectro-polarimetric data

Flat-fielding spectro-polarimetric data with one spatial and one spectral dimension is inherently difficult as the imprint of the spectral lines needs to be separated from other wavelength-dependent instrumental effect (e.g., fringes or prefilter profiles) and wavelength-independent effects (e.g., dust and sensor response). Current approaches for spectrometers are often based on moving the grating or they depend on optical models and/or on lab calibration data. They are also limited to small spectral regions and are instrument-specific. Approaches that would be suitable for polarimeters have not been reported yet. We present an approach that allows for flat-field calibration data to be to obtained for diffraction-grating-based, long-slit spectrographs combined with temporally modulated polarimetry from high-resolution solar telescopes. This approach is based on nominal flat-fielding procedures performed during the instrument's science operations. We performed a precise and field-dependent correction of the spectrographic distortion effect (resulting in curved spectral lines, typically denoted as a "smile" effect) to ensure the orthogonality of the spectral and spatial dimensions. We identified distortions by tracking the position of multiple spectral lines within the full spectral field of view. From the raw modulated flats, we then removed the solar line imprints and derived separate flat-fields for sensor and slit dust features. Optionally, wavelength calibration and continuum correction can be included in this process. We have created generic Python libraries that can be plugged into existing Python-based data reduction pipelines or used as a standalone calibration tool. We show that for spectrographs covering many spectral lines, a correction of the smile distortion based on optical models alone is not sufficient. Our results demonstrate a suppression of fringes, sensor artifacts, and fixed-pattern imprints in demodulated data by one order of magnitude. For intensity images, the photon noise level can be closely attained after calibration. Our correction works across the full spectral range. The algorithm was tested for different wavelength regimes with emission (EUV range) or absorption (near-UV, VIS, IR range) spectra, on data acquired with ground-based (SST/TRIPPLE-SP, GREGOR/GRIS), balloon-borne (SUNRISE-III/SUSI), and space-based (SolO/SPICE) instruments. The data calibrated with our method offer robust and precise inversion results. We have extended existing spectroscopic flat-field techniques to modern instruments with large imaging sensors covering many spectral lines simultaneously, and with polarimetric capabilities, where methods described so far are not adequate. We believe that our method is applicable as a standard calibration approach for most modern high resolution large-FOV, long-slit spectrographs -- both with and without polarimetric capabilities.

In-air micro-PIXE chemical state analysis of phosphorus and sulfur using a new parallel-beam wavelength-dispersive X-ray emission spectrometer

The proton induced K X-ray emission spectra of several different phosphorus and sulfur compounds were recorded with the new parallel-beam wavelength dispersive X-ray emission spectrometer. The spectrometer was installed recently at the external proton microbeam at the J. Stefan Institute to perform high energy resolution in-air micro-PIXE analysis in the tender X-ray range. Reported measurements are used to probe the capabilities of the spectrometer to perform also chemical state analysis. For phosphorus measurements, where the energy resolution of the spectrometer is the highest, a clear correlation between measured energy position of the Kα emission line and the phosphorus formal oxidation state is obtained. Chemical contrast is increased further in the Kβ emission spectra reflecting the structure of occupied valence molecular orbitals defined by the first coordination shell around the central phosphorus atom. A reasonable chemical contrast is maintained also in the sulfur Kβ emission spectra, despite the fact that the energy resolution of the spectrometer declines with increasing X-ray energy. Finally, an example of phosphorus speciation in reference biological material is presented, demonstrating the feasibility of the new setup to extend the capabilities of in-air micro-PIXE analysis towards chemical speciation.

Influence of anterior fracture line on anterior cortical reduction loss after cephalomedullary nail fixation in intertrochanteric fractures

To investigate the position of the anterior fracture line in AO/Orthopaedic Trauma Association (AO/OTA) type A2 unstable intertrochanteric fractures and its impact on the incidence of anterior cortical reduction loss after cephalomedullary nail fixation. A clinical data of 95 patients with intertrochanteric fractures who met the selection criteria between April 2020 and February 2023 was retrospectively analyzed. All patients were treated with cephalomedullary nail fixation, and the intra- and post-operative imaging data were complete. Among them, there were 37 males and 58 females. The age ranged from 61 to 97 years, with an average of 79.6 years. The time from injury to operation ranged from 7 hours to 11 days, with an average of 2.8 days. According to the 2018-AO/OTA classification standard, there were 39 cases of type 31-A2.2 and 56 cases of type 31-A2.3. Intraoperative fluoroscopy was used to record the number of patients with satisfactory fracture alignment. The preoperative CT data were imported into Mimics17.0 software to simulate the fracture reduction and measure the distance between the anterior fracture line and the intertrochanteric line bony ridge. The fractures were classified as transcapsular fractures, extra-capsular fractures, and intra-capsular fractures according to the distance. CT three-dimensional reconstruction was performed within 2 weeks after operation to observe the number of patients with anterior cortical reduction loss. The postoperative anterior cortical reduction loss incidence in patients with satisfactory fracture alignment, and the relationship between postoperative anterior cortical reduction loss and the position of the anterior fracture line were observed. There were 52 cases (54.7%) of transcapsular fractures, 24 cases (25.3%) of extra-capsular fractures, and 19 cases (20.0%) of intra-capsular fractures. Among them, 41 of the 52 transcapsular fractures had satisfactory fracture alignment, and 4 (9.8%) of them experienced anterior cortical reduction loss after operation; 19 of the 24 extra-capsular fractures had satisfactory fracture alignment, and no anterior cortical reduction loss occurred; 16 of the 19 intra-capsular fractures had satisfactory fracture alignment, and 7 (43.8%) of them experienced anterior cortical reduction loss after operation. There was a significant difference in the incidence of anterior cortical reduction loss between groups ( χ 2=8.538， P=0.003). All patients were followed up 3-26 months (mean, 9 months). Among them, 91 cases had fracture healing, and 4 cases had nonunion. In AO/OTA type A2 unstable intertrochanteric fractures, where the anterior fracture line is located within the joint capsule, there is a high risk of anterior cortical reduction loss after operation.

Correlation between combined deflection angle classification adduction typing and complications after internal fixation of adduction femoral neck fracture

To analyze the correlation between postoperative complications and combined deflection angle classification adduction type (CDAC-ADT) of femoral neck fractures after cannulated screw internal fixation. The clinical data of 121 patients with CDAC-ADT femoral neck fracture admitted between January 2018 and December 2021 and met the selected criteria were retrospectively analyzed. There were 69 males and 52 females, the age ranged from 19 to 79 years (mean, 48.1 years). The causes of injury included 52 cases of traffic accident, 24 cases of falling from height, and 45 cases of fall. The time from injury to operation ranged from 2 to 12 days, with an average of 6.0 days. Among them, there were 18 cases of CDAC-ADT type Ⅰ, 46 cases of type Ⅱ, and 57 cases of type Ⅲ; 6 cases of Garden type Ⅱ, 103 cases of type Ⅲ, and 12 cases of type Ⅳ; and according to the location of the fracture line, there were 26 cases of subcapitate type, 88 cases of transcervical type, and 7 cases of basal type. All patients were treated with cannulated screw internal fixation. The occurrence of complications (including internal fixation failure, fracture nonunion, and osteonecrosis of the femoral head) was recorded, and the correlation between complications and CDAC-ADT typing, Garden typing, and fracture line location were analyzed. The patients were followed up 8-44 months, with a mean of 24.9 months. There were 10 cases of internal fixation failure, 7 cases of fracture nonunion, and 30 cases of osteonecrosis of the femoral head after operation. Correlation analysis showed that patients' CDAC-ADT typing was significantly correlated with the overall incidence of complication and the incidence of internal fixation failure, fracture nonunion, and osteonecrosis of the femoral head ( P<0.05), and the Pearson coefficient of contingency were 0.435, 0.251, 0.254, and 0.241, respectively. Garden typing did not correlate with the overall incidence of complication and the incidence of internal fixation failure and fracture nonunion ( P>0.05), but correlated with the incidence of osteonecrosis of the femoral head ( P<0.05), and the Pearson coefficient of contingency was 0.251. Fracture line position typing had no correlation with the overall incidence of complication and the incidence of internal fixation failure, fracture nonunion, and osteonecrosis of the femoral head ( P>0.05). CDAC-ADT typing has obvious correlation with postoperative complications of femoral neck fracture and can be used to predict complications of femoral neck fracture.