Short Segments Research Articles

Efficient Extraction of Horizontal and Vertical Alignment Information for Roadways Using Public Data and Open Application Programming Interfaces

An open-source program was developed to extract horizontal and vertical alignment information from roadways using public data and open application programming interfaces. The program employs unsupervised analysis to detect, segment, classify, and measure curves and tangents along an individual route or a network of connected routes. The algorithms used in the horizontal and vertical alignment analyses were described. For vertical alignment, the route was segmented based on the vertical grade profile using a data structure change method. Erratic vertical grade data points at bridges were detected and replaced with estimated values. Two validation cases are provided to demonstrate the function of the program. The first case is an 11.0 km Interstate highway route. The second case is a network of 13 connected routes at a highway interchange. A visual inspection of the results showed that the program was able to detect and measure horizontal and vertical alignment segments with reasonable accuracy. Occasional inaccuracies in the vertical alignment analysis were observed, mainly at short segments near bridges. The program was developed in the R language. The complete source code of the program is publicly accessible via a dedicated GitHub repository.

A new oversampling-based full-duplex radar jamming method with a single antenna

With the fast development of jamming technology, strong coherent jamming based on digital radio frequency memory (DRFM) technology poses serious threats to radar detection capabilities due to their flexibility and deception characteristics. However, the extremely high isolation between transmitter and receiver is difficult to implement in practice, and jammers typically operate in a transmit/receive time-sharing mode. Consequently, the duty cycle of jamming signal received by radar is less than 100% in the time domain, enabling the radar systems to detect targets amidst jamming. To generate a full duty cycle jamming signal, a new oversampling-based full-duplex DRFM jamming generation method is proposed in the transmit/receive time-sharing mode. This method requires that the intercepting width of jammer must be less than the reciprocal of value which is the product of forwarding times incremented by one and the radar signal bandwidth. Therefore, the jammer first intercepts extremely short segments from the radar signal using oversampling, with lengths measured in nanoseconds. Then, the jammer rapidly re-modulates and re-transmits the intercepted signal segments within the corresponding interception period. The jamming signal is filtered by the radar receiver. Then, the spectrum of the signal only contains the complete fundamental component, and the pulse width of the signal matches that of the transmitted signal, achieving a duty cycle of 100% and realizing the full-duplex jamming effect. In addition, the frequency modulation technique is utilized to generate dense false targets corresponding to the transmitted signal, thereby improving jamming efficiency. This paper elucidates the generation mechanism and ramifications of the jamming signal through rigorous signal analysis, delineating the relationship between intercepting length and full-duplex radar jamming generation across various DRFM jamming styles. Finally, the efficacy of full-duplex jamming is substantiated through theoretical analysis and simulation.

Quasi-static and dynamic shear-out resistance in a steel fin-plate connection: An experimental and numerical investigation

This study presents an experimental and numerical investigation into the structural collapse of a fin-plate connection due to column loss, by subjecting the joint to quasi-static and dynamic loading conditions. The joint connection was designed using short segments of HEB220 and IPE160 sections for the column and beam, respectively, with the aim to promote bearing failure as the predominant failure mode. The experimental results revealed the same collapse modes induced by shear-out failure of the beam web under both low and high loading rates. Despite the increased resistance of the joint at high loading rates, high deflections and low energy dissipation were observed. The experimental results were complemented by numerical findings from a validated finite element model in Abaqus/Explicit. Even though a good agreement between experiments and numerical simulations was achieved, the numerical model overestimated the displacement at failure due to the limitations of the customary material model. The findings of this study demonstrate the deficiencies of fin-plate connections in a sudden column loss scenario.

Ultrafast supercontinuum sculpting for two-photon spectroscopy and microscopy of ratiometric fluorescent indicators

We present a compact laser system for quantitative two-photon excitation spectra measurements and ratiometric two-photon imaging of fluorescent protein indicators. The fundamental of the system is a short segment of photonic crystal fiber (PCF), which supports a nonlinear transformation of low-power ultrashort pulses by preserving temporal coherence, and this generates an ultrafast almost octave-spanning supercontinuum (SC). Accurate sculpting of the SC by its amplitude and phase modulation provides implementation of the spectroscopic and microscopic modalities. The spectroscopic one was exhibited by two-photon action cross section spectra measuring for the genetically encoded fluorescent sensing proteins of the vital biochemical parameters: acidity (SypHer3s), concentration of hydrogen peroxide (HyPer3 and HyPer7), redox status of NADH and glutathione (RexYFP and Grx1-roGFP2), hypohalous acids and their derivatives (Hypocrates). For the microscopy, we investigated and optimized the intensity pump pulse profiles under the high numerical objective by dispersion scan technique. We conducted real-time monitoring of the dynamics of hydrogen peroxide in HeLa cells with subcellular spatial resolution by means of ratiometric two-photon imaging of Hyper7 sensors. The presented hybrid laser system provides an ideal optical toolbox in order to develop ratiometric fluorescent sensors, which can be visualized in vivo using two-photon microscopy.

Design passive magnetic mechanisms with modular magnet configuration for axial gas force balance in miniature scroll compressors

Miniature scroll compressors (MSCs) are recognized for their superior characteristics—compact design, silent operation and energy-saving performance. One of its main challenges is to maintain dynamic sealing between the fixed and orbiting scrolls during the operation. This paper adopts a passive magnet mechanism (PMM) to balance the axial gas force in MSCs. The PMM with an integral magnet configuration (IMC) is investigated first, and the dimensions of the magnet and fixed ring are found as the paramount factors to determine the magnitude of axial magnetic force. However, the IMC is unable to follow the unsteady characteristics of the target axial gas force, so the scrolls will experience a large period of over-sealing during its operation.To overcome this limitation, an innovative modular magnet configuration (MMC) is proposed and investigated. The height of each magnet segment is treated as individual design variable, and genetic algorithm optimization is carried out to seek for the best force balance performance according to two indices—maximum force difference (MFD) and integral-average force difference (IAFD). With precise design of each magnet segment, the MMC is able to provide unsteady magnetic force and thus better balance performance. Compared with the IMC, the improvements are up to 52 % reduction of MFD and 66 % reduction of IAFD. The derived superior MMC designs reveal a common characteristic that the “N” and “E” magnets have short segments at their outer fringe and the “S” and “W” magnets have short segments at their inner fringe. The axial magnetic force characteristics of the IMC and MMC are validated by prototype experiments.

In silico analysis on frequency and distribution of microsatellites in genes associated with spinal cord astrocytoma

Microsatellites, also called short tandem repeats (STRs) or simple sequence repeats (SSRs) are short DNA sequence segments consisting of tandemly repeated motifs. SSRs are regarded as one of the most effective tools for genetic research. In this study, we conducted an in silico analysis to investigate the presence, distribution, and characteristics of SSRs within the genes associated with spinal cord astrocytoma. The aim of this study was to identify SSRs in coding and non-coding regions, analyze their correlation with gene parameters, and determine the GC content in the gene sequences. The results revealed that the widespread presence of SSRs within the genes is associated with spinal cord astrocytoma (SCA). The distribution of SSR motifs varied among the analyzed genes, and certain motifs were common across multiple genes. Additionally, we observed a strong positive correlation between the total number of SSRs and gene size, indicating that larger genes tend to have a higher number of microsatellites. Furthermore, we identified SSRs in both coding and non-coding regions of the genes. The incidence of SSRs and cSSRs differed among genes, suggesting potential functional implications for gene expression and regulation. Our study provides valuable insights into the genetic diversity within the astrocytoma genes and highlights the potential significance of SSRs in gene regulation. In conclusion, this study contributes to a better understanding of the role of microsatellites within the genes associated with spinal cord astrocytoma. The observed patterns of SSR distribution and characteristics suggest their potential functional relevance in the development and progression of astrocytoma.

Impact of burial depth and root segment length on vegetative propagation of common milkweed (Asclepias syriaca)

Abstract Common milkweed (Asclepias syriaca L.) is widely planted as part of monarch butterfly (Danaus plexippus) conservation efforts. Vegetative propagation is an alternative to planting A. syriaca from seed, which offers advantages such as high emergence rates. The aim of this study was to determine the ideal planting depth and initial root segment length to vegetatively propagate A. syriaca. In a greenhouse trial with two runs, A. syriaca was grown from seed and then 3, 8 and 15-cm segments were harvested. These segments were then planted at depths of either 3, 8, or 15 cm. Planting depth did not impact A. syriaca growth, but an initial root segment length of 15 cm was associated with greater above- and belowground biomass and height in both runs of the experiment. Emergence rates were not impacted by either factor. Overall, A. syriaca was likely to establish regardless of the initial root segment length or planting depth, but plants grown from root segments of 15 cm were more vigorous than plants grown from shorter segments.

The BICD2 dynein cargo adaptor binds to the HPV16 L2 capsid protein and promotes HPV infection.

During entry, human papillomavirus (HPV) traffics from the endosome to the trans Golgi network (TGN) and Golgi and then the nucleus to cause infection. Although dynein is thought to play a role in HPV infection, how this host motor recruits the virus to support infection and which entry step(s) requires dynein are unclear. Here we show that the dynein cargo adaptor BICD2 binds to the HPV L2 capsid protein during entry, recruiting HPV to dynein for transport of the virus along the endosome-TGN/Golgi axis to promote infection. In the absence of BICD2 function, HPV accumulates in the endosome and TGN and infection is inhibited. Cell-based and in vitro binding studies identified a short segment near the C-terminus of L2 that can directly interact with BICD2. Our results reveal the molecular basis by which the dynein motor captures HPV to promote infection and identify this virus as a novel cargo of the BICD2 dynein adaptor.

Factors associated with loss of vertebral height and kyphosis correction after intermediate screws in short segment pedicular fixation for type-A fractures of the thoracolumbar spine: A retrospective study.

In this article, we attempted to identify risk factors affecting the loss of vertebral height and kyphosis correction on type A thoracolumbar fractures. Patients with type A thoracolumbar fractures who underwent short segments with intermediate screws at the fracture level management between 2017 and 2022 were included in this study. Clinical factors including patients' demographic characteristics (age, sex), history (smoking, hypertension and/or diabetes), value of height/kyphosis correction, the thoracolumbar injury classification and severity score (TLICS), the load sharing classification (LSC) scores and bone mineral density were collected. Correlation coefficient, simple linear regression analysis and multivariate regression analysis were performed to identify the clinical factors associated with the loss of vertebral height/kyphosis correction. Finally, 166 patients were included in this study. The mean height and kyphosis correction were 21.8% ± 7.5% and 9.9° ± 3.8°, respectively, the values of the loss were 6.5% ± 4.0% and 3.9° ± 1.9°, respectively. Simple linear regression analysis and multivariate regression analysis showed that age, value of height correction, LSC scores and bone mineral density were significantly associated with the loss of vertebral height and kyphosis correction (P < .01) We could draw the conclusion that patients with older age, lower bone mineral density, higher LSC scores and diabetes are at higher risk of vertebral height and kyphosis correction loss increase. For these patients, appropriate clinical measures such as long segment fixation, control of blood glucose, and increase of bone density must be taken to reduce the loss of correction.

Recurrence plot embeddings as short segment nonlinear features for multimodal speaker identification using air, bone and throat microphones

Speech is produced by a nonlinear, dynamical Vocal Tract (VT) system, and is transmitted through multiple (air, bone and skin conduction) modes, as captured by the air, bone and throat microphones respectively. Speaker specific characteristics that capture this nonlinearity are rarely used as stand-alone features for speaker modeling, and at best have been used in tandem with well known linear spectral features to produce tangible results. This paper proposes Recurrent Plot (RP) embeddings as stand-alone, non-linear speaker-discriminating features. Two datasets, the continuous multimodal TIMIT speech corpus and the consonant-vowel unimodal syllable dataset, are used in this study for conducting closed-set speaker identification experiments. Experiments with unimodal speaker recognition systems show that RP embeddings capture the nonlinear dynamics of the VT system which are unique to every speaker, in all the modes of speech. The Air (A), Bone (B) and Throat (T) microphone systems, trained purely on RP embeddings perform with an accuracy of 95.81%, 98.18% and 99.74%, respectively. Experiments using the joint feature space of combined RP embeddings for bimodal (A–T, A–B, B–T) and trimodal (A–B–T) systems show that the best trimodal system (99.84% accuracy) performs on par with trimodal systems using spectrogram (99.45%) and MFCC (99.98%). The 98.84% performance of the B–T bimodal system shows the efficacy of a speaker recognition system based entirely on alternate (bone and throat) speech, in the absence of the standard (air) speech. The results underscore the significance of the RP embedding, as a nonlinear feature representation of the dynamical VT system that can act independently for speaker recognition. It is envisaged that speech recognition too will benefit from this nonlinear feature.

A unifying model for membrane protein biogenesis.

α-Helical integral membrane proteins comprise approximately 25% of the proteome in all organisms. The membrane proteome is highly diverse, varying in the number, topology, spacing and properties of transmembrane domains. This diversity imposes different constraints on the insertion of different regions of a membrane protein into the lipid bilayer. Here, we present a cohesive framework to explain membrane protein biogenesis, in which different parts of a nascent substrate are triaged between Oxa1 and SecY family members for insertion. In this model, Oxa1 family proteins insert transmembrane domains flanked by short translocated segments, whereas the SecY channel is required for insertion of transmembrane domains flanked by long translocated segments. Our unifying model rationalizes evolutionary, genetic, biochemical and structural data across organisms and provides a foundation for future mechanistic studies of membrane protein biogenesis.

3D Imaging Reveals Complex Microvascular Remodeling in the Right Ventricle in Pulmonary Hypertension.

Pathogenic concepts of right ventricular (RV) failure in pulmonary arterial hypertension focus on a critical loss of microvasculature. However, the methods underpinning prior studies did not take into account the 3-dimensional (3D) aspects of cardiac tissue, making accurate quantification difficult. We applied deep-tissue imaging to the pressure-overloaded RV to uncover the 3D properties of the microvascular network and determine whether deficient microvascular adaptation contributes to RV failure. Heart sections measuring 250-µm-thick were obtained from mice after pulmonary artery banding (PAB) or debanding PAB surgery and properties of the RV microvascular network were assessed using 3D imaging and quantification. Human heart tissues harvested at the time of transplantation from pulmonary arterial hypertension cases were compared with tissues from control cases with normal RV function. Longitudinal 3D assessment of PAB mouse hearts uncovered complex microvascular remodeling characterized by tortuous, shorter, thicker, highly branched vessels, and overall preserved microvascular density. This remodeling process was reversible in debanding PAB mice in which the RV function recovers over time. The remodeled microvasculature tightly wrapped around the hypertrophied cardiomyocytes to maintain a stable contact surface to cardiomyocytes as an adaptation to RV pressure overload, even in end-stage RV failure. However, microvasculature-cardiomyocyte contact was impaired in areas with interstitial fibrosis where cardiomyocytes displayed signs of hypoxia. Similar to PAB animals, microvascular density in the RV was preserved in patients with end-stage pulmonary arterial hypertension, and microvascular architectural changes appeared to vary by etiology, with patients with pulmonary veno-occlusive disease displaying a lack of microvascular complexity with uniformly short segments. 3D deep tissue imaging of the failing RV in PAB mice, pulmonary hypertension rats, and patients with pulmonary arterial hypertension reveals complex microvascular changes to preserve the microvascular density and maintain a stable microvascular-cardiomyocyte contact. Our studies provide a novel framework to understand microvascular adaptation in the pressure-overloaded RV that focuses on cell-cell interaction and goes beyond the concept of capillary rarefaction.

Enhancement of flame stability by a short Pt segment for CH4/H2 blended fuels in a micro-flow reactor

Effects of a Pt segment on flame stability of CH4/H2/air mixtures in a micro-flow reactor were numerically scrutinized, which demonstrated that flame instabilities were completely suppressed. In addition, the response of flame position to inlet velocity exhibited two C-shaped curves, which was divided into regimes A, B and C for high, medium and low inlet velocities, respectively. Flame bifurcation occurred in regime B. A case study of regime B showed that the increased generation rate of H(s) caused the main H2O(s) formation reaction shift from OH(s)+OH(s)=H2O(s)+O(s) to H(s)+OH(s)=H2O(s)+PT(s). This led to a decreased O(s) coverage and an increased PT(s) coverage, which prevented C(s) from reacting with sufficient O(s) to form CO2(s). As a result, CO(s) accumulated on the catalytic surface and flame bifurcation occurred. The dynamic processes from regime B to A and C were also examined, which manifested that a threshold value existed for the adsorption rate of H atoms. Once the threshold value was exceeded, the reaction pathway of OH(s) has undergone a transformation. In conclusion, this study uncovered the influence of heterogeneous reactions on gas combustion of CH4/H2 blends, and provided an effective and economic technology for flame stability enhancement in micro-flow reactors.

Impact of preaneurysmal M1 length in unruptured middle cerebral artery aneurysm: mid-term outcome and single-center experience

ObjectiveThis study was design to investigate the surgical and functional outcome based on the preaneurysmal M1 length for unruptured MCA aneurysm. MethodsAmong 250 consecutive patients with unruptured aneurysms operated in our institution between 2015 and 2017, 72 were MCA aneurysms. Risk factors for IR (i.e., intraoperative rupture) were investigated including age, sex, preaneurysmal M1 length, maximal MCA aneurysm diameter, neck size, aneurysm shape, sphenoid ridge proximation sign. Outcome was measured at discharge, 1 yr and last follow-up. Outcome was compared according to the preaneurysmal M1 length. ResultsAmong 68 patients included, five patients (7.3%) suffered IR. Mean maximal diameter of MCA aneurysm (7.9 mm ± 3.4 vs. 4.5 ± 1.8; p = 0.01) was significantly associated with IR risk. Mean M1 length seemed to be shorter in the IR group although not statistically significant (16.2 mm ± 5.1 vs. 11.5 mm ± 4.8; p = 0.053). Mid-term outcome was favorable for all patients at last follow-up but was worsen in case of short preaneurysmal M1 segment (10.7 mm ± 4.8 vs. 16.4 mm ± 5.3, p = 0.02). Complete aneurysm occlusion was achieved for sixty-nine patients (95.5%) with 6.9% of early postoperative complications. ConclusionsThe microsurgical treatment of unruptured MCA aneurysm was associated with favorable mid-term outcome in all patients and high rates of complete occlusion. Aneurysm size was significantly associated with the intraoperative rupture risk for unruptured MCA aneurysm and patients with a short preaneurysmal M1 segment seemed to have a greater risk of intraoperative rupture although not statistically significant. Short preaneurysmal M1 patients had worsen mid-term outcome.

Transoral endoscopic assisted reduction and internal fixation of mandibular condylar neck fractures with short condylar segment

This study aimed to assess the reliability and safety of transoral endoscopic-assisted reduction internal fixation (TERIF) for treating short-segment condylar neck fractures (CNF), including hardware removal.Patients with displaced CNF and short condylar segments treated using TERIF were included in the study. Clinical evaluation covered dental occlusion, range of mouth opening, deviation during mouth opening, protrusion, laterotrusion, pain, and chewing. Radiological evaluation was used to assess fracture displacement, angulation, head dislocation, postoperative reduction, fixation stability, and bone healing. The same technique was used to treat 15 patients with 18 CNF and short condylar segments. Hardware removal was performed for nine fractures in eight patients after fracture healing using the same approach.All patients regained satisfactory, pain-free mouth opening with no deviation and complete bone healing. Computed tomographic images displayed adequate reduction and stable fixation during the follow-up period for all patients. No temporary or permanent facial nerve impairment occurred in any of the patients.TERIF is a reliable and safe treatment for CNF with short condylar segments, even in the presence of head dislocation, medial override, and malunited fractures; hardware can be safely removed after healing using the same approach.

Embolization of Vessels With Irregular Lumen Using the Coil Packing Technique Between the Amplatzer Vascular Plug II Lobes.

The Amplatzer Vascular Plug(AVP) series enables precise positioning and high migration resistance, allowing embolization in short segments; however, inadequate embolization or recanalization may occasionally occur. We hypothesized that leaks may occur when AVPs are implanted in vessels with irregular lumen due to insufficient adherence to the vessel. This hypothesis was tested by experiments with a vascular model. We employed a coil packing technique between the AVP lobes to embolize internal iliac arteries with an irregular lumen. Saline was injected through the Y-shaped glass tubes of the stenotic and the smooth model (without stenotic lesion), and the amount of leakage was measured when the AVP was deployed. The feasibility and effectiveness of filling coils between the lobes of AVP II were evaluated. A total of 11 cases were retrospectively reviewed using this technique for internal iliac artery embolization prior to endovascular aortic repair. The amount of leakage was significantly higher in the presence of stenotic lesions.Insertion of a 2.2 F microcatheter from the side of the proximal lobe of AVP II and filling of coils was achieved in all 11 cases. Follow-up contrast-enhanced CT showed no recanalization, leakage, or other obvious complications. Coil packing technique around Amplatzer Vascular Plugs could be an effective method and a reliable option for arterial embolization, especially in vessels with irregular lumens.

Operative Management of Intra-abdominal Lymphatic Malformations in Children: A Single Tertiary Center Experience

BackgroundIntra-abdominal lymphatic malformations (LMs) are relatively rare congenital anomalies and can be divided into intra- and retroperitoneal subgroups. This study aims to evaluate the outcomes after surgical resection of intraperitoneal LMs in children. MethodsThe records of all patients ≤16 years of age with intraperitoneal LMs managed at our tertiary center between 2007–2022 were reviewed. Patients with retroperitoneal LMs were excluded. Our preferred approach is surgical exploration for large (>5 cm), symptomatic lesions if they are potentially resectable on imaging. ResultsA total of 12 patients (10 males) were diagnosed with intraperitoneal LMs located in the small bowel mesentery or omentum at a median age of 6.6 (range, 0.6−14.4) years. Ten (83%) patients presented with acute symptoms, including abdominal pain (n = 8; 67%) and vomiting (n = 3; 25%). Two (17%) intraperitoneal LMs were found on imaging performed for other reasons. Surgical exploration was performed in 11/12 (92%) cases. Intestinal volvulus around a mesenteric macrocyst had occurred in 4 (36%) patients. Complete macroscopic resection was achieved in 10/11 (91%) patients. Most lesions were localized to a short intestinal segment. One mixed type LM with an extensive mesenteric involvement was biopsied as the lesion was deemed to be unresectable in preoperative imaging and the diagnosis was initially unclear. There was one recurrence (8%) during postoperative follow-up on imaging (median 3.6 (range, 1.5−6.9) years) but the patient has remained asymptomatic and not undergone interventions. 6/8 (75%) of screened intraperitoneal LMs were positive for a somatic PIK3CA mutation. ConclusionsMost large, pedunculated macrocystic LMs in the small bowel mesentery or omental location were amenable to macroscopic resection. Intraperitoneal LMs tend to present with acute symptoms including a risk for intestinal volvulus based on anatomical location. Our results suggest low recurrence rates or need for further interventions over follow-up. Level of EvidenceIII.

Sampling Earth’s mantle at intra-transform spreading ridges

The Doldrums transform system, located in the Equatorial Atlantic at 7–8°N, is a 110 km-wide multi-fault shear zone, with five active transform faults separated by four short intra-transform ridge segments (ITRs). The two central ITRs, ITR-2 and ITR-3, are significantly deeper than the peripheral ridge segments, suggesting differences in the thermal conditions of the sub-ridge mantle. New chemical and radiogenic isotope data from on-axis lavas erupted across the transform domain reveal that the basalts from ITR-3 are enriched in alkalis (Na2O + K2O = 4.3 wt%; Na8 up to 3.7) and light rare earth elements (La/Sm)N = 0.86–0.97). However, these basalts have lower Sr and Pb isotope ratios than MORB from the Equatorial Atlantic (i.e., 87Sr/86Sr ∼ 0.70237 and 206Pb/204Pb ∼ 18), and relatively high Nd and Hf isotope ratios (143Nd/144Nd = 0.51315–0.51325; 176Hf/177Hf = 0.2832–0.28325). Hence, the mantle underlying ITR-3 is, on average, depleted in highly incompatible elements. Thermal models of the sub-ridge mantle show that it is also the coldest mantle region under the Doldrums system with the lowest crust production. Considering its location in the central transform domain, it is likely that the local mantle underwent melting beneath adjacent segments of the Mid-Atlantic Ridge (MAR) before remelting below ITR-3. We propose that the initial melting event beneath the MAR selectively removed the most fusible, geochemically enriched mantle components, leaving behind a predominantly peridotitic source, characterized by comparatively low Sr and Pb isotope ratios. Therefore, MORB from intra-transform ridge segments, such as those within the Doldrums transform system, provide a rare opportunity to constrain the isotopic composition of highly incompatible element depleted peridotitic mantle, which is a ubiquitous, but otherwise often camouflaged component of Earth’s mantle.

Study on the Results of Laminectomy with Short Segment Pedicle Screw Fixation in Dorsolumbar Fractures with Respect to Anatomical Reduction, Functional Recovery, and Pain

Abstract Background: This study aimed to report the results of laminectomy with short-segment pedicle screw fixation in thoracolumbar fracture. Materials and Methods: Forty-two patients were analyzed prospectively, and followed up in the outpatient department for 24 months. Results: The results revealed that most of the patients in the study had reasonable to good neurological recovery in the postoperative period assessed in the form of an American spinal injury association impairment scale (ASIA) score. There was also an excellent improvement in the components of anatomical reduction like vertebral height, Cobb’s angle, and anterior wedge angle, which was directly related to the functional recovery of the patient. Postoperatively, the patients also got relief in pain in the dorsolumbar region assessed based on the Denis pain scale. Conclusion: This study concludes that laminectomy with pedicle screw fixation is an excellent option for patients with thoracolumbar fracture, it not only decompresses the spine but also provides stability with minimal manageable complications.

Assessment of temporal changes in glomerular filtration rate following clamp ischemia in male and female rats using transcutaneous FITC-sinistrin clearance

Warm arterial clamping with reperfusion in rats is a commonly utilized model of ischemic kidney injury (IRI). Traditionally, changes in plasma creatinine or creatinine clearance have been utilized to assess kidney function in this model. A limitation of these approaches, however, is that changes in plasma creatinine are relatively slow to occur, resulting in low temporal fidelity. This limits our ability to relate changes in kidney function to histo-pathological changes observed during reperfusion of the kidneys. Transcutaneous assessment of FITC-sinistrin clearance enables accurate, repeated measurement of glomerular filtration rate in conscious animals over short segments of time (hours) without drawing blood. The goal of the current study was to characterize temporal changes in renal function in male and female rats after reperfusion from bi-lateral warm arterial clamp ischemia using transcutaneous FITC-sinistrin clearance. Our study was performed in age matched male (n=8) and female (n=5) Sprague Dawley rats (12-20wks of age). FITC sinistrin clearance was measured by affxing a miniaturized transcutaneous measurement device between the shoulder blades (MediBeacon) of rats. 50mg/kg of FITC-sinistrin was then injected i.v via the tail vein and the device allowed to record for ~3 hours. Measurements were taken either at pre-surgery (baseline), 1-3 hours, 24 hours or 7 days following reperfusion of the kidneys from warm bilateral arterial clamp ischemia. For the ischemic surgery, animals were anesthetized with isoflurane (2-5%, 95% O2) and the right and left kidneys were accessed by flank incisions. After being exposed, the renal arteries were separated from the renal veins via dissection. Both renal arteries were then clamped with microserrefines for 45 minutes. After the ischemic period, the clamps were removed, allowing blood flow to be restored to the kidneys. Body temperature was measured via a rectal probe and maintained at 37°C throughout the procedure by a servo-controlled heating table and UV heating lamp. The wounds were then closed, and the animals allowed to recover. Buprenorphine was administered as an analgesic. For each measurement, the ½ life of FITC sinistrin was determined using a 1-compartment model (MB Lab software) and glomerular filtration rate (GFR) per 100g of body weight rate calculated. Baseline GFR was 0.94±0.03ml/min/100g in males and 1.09±0.02/min/100g in females (PTTEST=0.04). Following 45 minutes of warm bilateral arterial ischemia and reperfusion, GFR fell to 0.24±0.08ml/min/100g in male and 0.36±0.15ml/min/100g in females within 1-3 hours of reperfusion. At 24 hours of reperfusion, GFR averaged 0.06±0.03ml/min/100g in males and 0.28±0.16ml/min/100g in females. GFR recovered in males and females by 7 days of reperfusion averaging 0.86±0.10ml/min/100g in males and 0.83±0.00ml/min/100g in females. There was no significant difference between FITC-sinistrin clearance between males and females at any time point after IRI. Our data indicate that most of the reduction in GFR is present immediately after releasing the clamp. This is consistent with continued vascular disturbances mediating the initial decline in glomerular filtration rate in this model (i.e. vasospasm). The absence of sex differences in GFR decline using this method suggests that sex-differences detected using plasma creatinine may be, at least in part, secondary to the more rapid production of creatinine in males than in females or greater baseline filtration/body weight ratio in females compared to males rather than differences in renal function decline to ischemia. American Heart Association Transformational Project Award 970585 to Paul O'Connor. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.