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PURPOSE: The potential relationship between mastication ability and cognitive function in idiopathic normal pressure hydrocephalus (iNPH) patients is unclear. This report investigated the association between mastication and cognitive function in iNPH patients using the gray level of the co-occurrence matrix on the lateral pterygoid muscle. METHODS: We analyzed data from 96 unoperated iNPH patients who underwent magnetic resonance imaging (MRI) between December 2016 and February 2023. Radiomic features were extracted from T2 MRI scans of the lateral pterygoid muscle, and muscle texture parameters were correlated with the iNPH grading scale. Subgroup analysis compared the texture parameters of patients with normal cognitive function with those of patients with cognitive impairment. RESULTS: The mini-mental state examination score correlated positively with the angular second moment (P < 0.05) and negatively with entropy (P < 0.05). The dementia scale (Eide's classification) correlated negatively with gray values (P < 0.05). Gray values were higher in the cognitive impairment group (64.7 ± 16.6) when compared with the non-cognitive impairment group (57.4 ± 13.3) (P = 0.005). Entropy was higher in the cognitive impairment group (8.2 ± 0.3) than in the non-cognitive impairment group (8.0 ± 0.3) (P < 0.001). The area under the receiver operating characteristic curve was 0.681 (P = 0.003) and 0.701 (P < 0.001) for gray value and entropy, respectively. CONCLUSION: Our findings suggest an association between heterogeneity of mastication and impaired cognitive function in iNPH patients and highlight muscle texture analysis as a potential tool for predicting cognitive impairment in these patients.
Subject(s)
Cognition , Cognitive Dysfunction , Hydrocephalus, Normal Pressure , Magnetic Resonance Imaging , Pterygoid Muscles , Humans , Hydrocephalus, Normal Pressure/diagnostic imaging , Hydrocephalus, Normal Pressure/surgery , Hydrocephalus, Normal Pressure/psychology , Hydrocephalus, Normal Pressure/physiopathology , Male , Female , Aged , Aged, 80 and over , Cognition/physiology , Cognitive Dysfunction/psychology , Cognitive Dysfunction/physiopathology , Cognitive Dysfunction/diagnostic imaging , Pterygoid Muscles/diagnostic imaging , Pterygoid Muscles/pathology , Mastication/physiologyABSTRACT
PURPOSE: A consensus on decompressive craniectomy for intracerebral hemorrhage (ICH) has not yet been established. We aimed to investigate the development of shunt-dependent hydrocephalus based on the method of ICH surgery, with a focus on craniectomy. METHODS: We retrospectively enrolled 458 patients with supratentorial ICH who underwent surgical hematoma evacuation between April 2005 and December 2021 at two independent stroke centers. Multivariate analyses were performed to characterize risk factors for postoperative shunt-dependent hydrocephalus. Propensity score matching (1:2) was undertaken to compensate for group-wise imbalances based on probable factors that were suspected to affect the development of hydrocephalus, and the clinical impact of craniectomy on shunt-dependent hydrocephalus was evaluated by the matched analysis. RESULTS: Overall, 43 of the 458 participants (9.4%) underwent shunt procedures as part of the management of hydrocephalus after ICH. Multivariate analysis revealed that intraventricular hemorrhage (IVH) and craniectomy were associated with shunt-dependent hydrocephalus after surgery for ICH. After propensity score matching, there were no statistically significant intergroup differences in participant age, sex, hypertension status, diabetes mellitus status, lesion location, ICH volume, IVH occurrence, or IVH severity. The craniectomy group had a significantly higher incidence of shunt-dependent hydrocephalus than the non-craniectomy group (28.9% vs. 4.3%, p < 0.001; OR 9.1, 95% CI 3.7-22.7), craniotomy group (23.2% vs. 4.3%, p < 0.001; OR 6.6, 95% CI 2.5-17.1), and catheterization group (20.0% vs. 4.0%, p = 0.012; OR 6.0, 95% CI 1.7-21.3). CONCLUSION: Decompressive craniectomy seems to increase shunt-dependent hydrocephalus among patients undergoing surgical ICH evacuation. The decision to perform a craniectomy for patients with ICH should be carefully individualized while considering the risk of hydrocephalus.
Subject(s)
Cerebral Hemorrhage , Hydrocephalus , Humans , Propensity Score , Retrospective Studies , Cerebral Hemorrhage/surgery , Craniotomy , Hydrocephalus/etiology , Hydrocephalus/surgeryABSTRACT
BACKGROUND: Recent guidelines recommended conducting spontaneous breathing trial (SBT) with modest inspiratory pressure augmentation rather than T-piece or continuous positive airway pressure. However, it was based on few studies focused on the outcomes of extubation rather than the weaning process, despite the existence of various weaning situations in clinical practice. This study was designed to investigate the effects of SBT with pressure support ventilation (PSV) or T-piece on weaning outcomes. METHODS: All consecutive patients admitted to two medical intensive care units (ICUs) and those requiring mechanical ventilation (MV) for more than 24 h from November 1, 2017 to September 30, 2020 were prospectively registered. T-piece trial was used until March 2019, and then, pressure support of 8 cmH2O and 0 positive end-expiratory pressure were used for SBT since July 2019, after a 3-month transition period for the revised SBT protocol. The primary outcome of this study was successful weaning defined according to the WIND (Weaning according to a New Definition) definition and were compared between the T-piece group and PSV group. The association between the SBT method and weaning outcome was evaluated with logistic regression analysis. RESULTS: In this study, 787 eligible patients were divided into the T-piece (n = 473) and PSV (n = 314) groups after excluding patients for a 3-month transition period. Successful weaning was not different between the two groups (85.0% vs. 86.3%; p = 0.607). However, the PSV group had a higher proportion of short weaning (70.1% vs. 59.0%; p = 0.002) and lower proportion of difficult weaning (13.1% vs. 24.1%; p < 0.001) than the T-piece group. The proportion of prolonged weaning was similar between the two groups (16.9% vs. 16.9%; p = 0.990). After excluding patients who underwent tracheostomy before the SBTs, similar results were found. Reintubation rates at 48 h, 72 h, and 7 days following the planned extubation were not different between the PSV and T-piece groups. Moreover, no significant differences in intensive care unit and hospital mortality and length of stay were observed. CONCLUSIONS: In critically ill medical patients, SBT using PSV was not associated with a higher rate of successful weaning compared with SBT using T-piece. However, PSV could shorten the weaning process without increasing the risk of reintubation.
Subject(s)
Critical Illness/therapy , Intensive Care Units , Positive-Pressure Respiration/methods , Ventilator Weaning/methods , Aged , Airway Extubation , Critical Illness/epidemiology , Female , Follow-Up Studies , Hospital Mortality/trends , Humans , Intubation, Intratracheal , Male , Middle Aged , Prospective StudiesABSTRACT
OBJECTIVE: The study aimed to examine the feasibility and long-term effects of a school-based eating disorder prevention program for young adolescents in Korea. METHOD: We followed up the students (n = 133) who had participated in the prevention program at 3 years ago to evaluate changes in body esteem and self-esteem between postintervention and 3-year follow-up, with investigating whether gender moderated the effect of time. RESULTS: Boys showed no decline in body esteem and self-esteem from postintervention to 3-year follow-up, indicating that the prevention program alleviated decreases in body esteem and self-esteem over time. Girls showed decreases in body esteem and self-esteem from postintervention to 3-years follow-up. DISCUSSION: This study provides evidence supporting the feasibility of the school-based eating disorder prevention program targeting mixed-sex, young adolescents in Korea. Given the developmental trajectories of decrease in body esteem and self-esteem during adolescence, the program may be efficient for boys over time. Boosters and/or complementary prevention approaches across gender are needed.
Subject(s)
Feeding and Eating Disorders , School Health Services , Adolescent , Body Image/psychology , Feasibility Studies , Feeding and Eating Disorders/prevention & control , Female , Follow-Up Studies , Humans , Male , Program Evaluation , Republic of Korea , Self ConceptABSTRACT
OBJECTIVES: The objective of this study was to investigate the risk factors for early medical emergency team reactivation (which is defined as repeated medical emergency team calls within 72 hr after the index medical emergency team call) in the patients remaining on the ward after index medical emergency team activation. DESIGN: Retrospective analysis with prospectively collected data. SETTING: A university-affiliated, tertiary referral hospital. PATIENTS: All consecutive patients over 18 years old who received medical emergency team intervention. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 3,989 cases eligible for analysis, 514 cases (12.9%) were classified into the reactivation group, with the remainder assigned to the nonreactivation group. In a multivariate analysis, chronic lung disease (odds ratio, 1.38; 95% CI, 1.03-1.86; p = 0.032), chronic liver disease (odds ratio, 1.44; 95% CI, 1.04-1.99; p = 0.028), activation due to bedside concern about overall deterioration without abnormal physiological variables (odds ratio, 1.30; 95% CI, 1.00-1.68; p = 0.049), advice or consultation only for medical emergency team intervention (odds ratio, 0.78; 95% CI, 0.63-0.97; p = 0.027), and discussion about treatment limitation (odds ratio, 0.39; 95% CI, 0.25-0.60; p < 0.001) were independently associated with medical emergency team reactivation. In the reactivation group, 249 patients (48.5%) were transferred to the ICU after repeated calls. Medical department admission (odds ratio, 1.68; 95% CI, 1.12-2.52; p = 0.012), chronic liver disease (odds ratio, 1.73; 95% CI, 1.07-2.79; p = 0.025), hematological malignancies (odds ratio, 1.63; 95% CI, 1.10-2.41; p = 0.015), and tachypnea at the end of medical emergency team were risk factors for medical emergency team reactivation requiring ICU admission. Discussion about treatment limitation (odds ratio, 0.14; 95% CI, 0.05-0.40; p < 0.001) was also associated with decreased risk of medical emergency team reactivation requiring ICU admission. CONCLUSIONS: An increased risk of early medical emergency team reactivation was associated with medical emergency team activation by bedside concern about overall deterioration and patients with chronic lung or liver disease.
Subject(s)
Early Medical Intervention/statistics & numerical data , Hospital Rapid Response Team/statistics & numerical data , Aged , Female , Hospitalization/statistics & numerical data , Humans , Intensive Care Units/statistics & numerical data , Male , Middle Aged , Retrospective Studies , Risk FactorsABSTRACT
We report the results of an experimental study of the characterization of second-order reflection bands from a cholesteric liquid crystal (CLC) cell that depends on the applied electric field, using a wide bandwidth wavelength-swept laser. The second-order reflection bands around 1300 nm and 1500 nm were observed using an optical spectrum analyzer when an electric field was applied to a horizontally oriented electrode cell with a pitch of 1.77 µm. A second-order reflection spectrum began to appear when the intensity of the electric field was 1.03 Vrms/µm with the angle of incidence to the CLC cell fixed at 36°. The reflectance increased as the intensity of the electric field increased at an angle of incidence of 20°, whereas at an incident angle of 36°, when an electric field of a predetermined value or more was applied to the CLC cell, it was confirmed that deformation was completely formed in the liquid crystal and the reflectance was saturated to a constant level. As the intensity of the electric field increased further, the reflection band shifted to a longer wavelength and discontinuous wavelength shift due to the pitch jump was observed rather than a continuous wavelength increase. In addition, the reflection band changed when the angle of incidence on the CLC cell was changed. As the angle of incidence gradually increased, the center wavelength of the reflection band moved towards shorter wavelengths. In the future, we intend to develop a device for optical wavelength filters based on side-polished optical fibers. This is expected to have a potential application as a wavelength notch filter or a bandpass filter.
ABSTRACT
We report in situ observation of dynamic pitch jumps in cholesteric liquid crystal (CLC) layers that depend on the applied electric field. A high-speed and wide bandwidth wavelength-swept laser is used as an optical broadband source to measure the dynamic pitch jumps. We could not observe the dynamic pitch jump in the quasi-static pitch variation. Instead, we carry out two driving methods, a normal driving and an overdriving method, in order to measure the dynamic pitch jump in the CLC cell. For the case of normal driving, it has been confirmed that the reflection band from the measurement region is discontinuously shifted by movement of the defect wall. The reflection band was compressed and recovered before the band moved, but the dynamic pitch jump of the helix could not be observed. For the case of overdriving, however, it was possible to observe the unwinding of the helix during the dynamic pitch jump. The entire dynamic pitch jump process in the CLC cell could be observed by measuring the transmission spectra from the CLC cell by varying the applied electric field. We confirm that the entire reaction time with the overdriving method was about 800 ms, which was shorter than with the normal driving method. This study contributes to the development of fast in-plane switching research and the development of new CLC devices.
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BACKGROUND AND OBJECTIVE: Limb muscle weakness is associated with difficult weaning. However, there are limited data on extubation failure. The objective of this cohort study was to evaluate the association between limb muscle weakness according to the Medical Research Council (MRC) scale and extubation failure rates among patients in a medical intensive care unit (ICU). METHODS: All consecutive medical ICU patients who were mechanically ventilated for more than 24 h and who were weaned according to protocol were prospectively registered, and limb muscle weakness was assessed using the MRC scale on the day of planned extubation. Association of limb muscle weakness with extubation failure within 48 h following planned extubation was evaluated with logistic regression analysis. RESULTS: Over the study period, 377 consecutive patients underwent planned extubation through a standardized weaning process. Extubation failure occurred in 106 (28.1%) patients. Median scores on the MRC scale for four limbs were lower in patients with extubation failure (14, interquartile range (IQR) 12-16) than in patients without extubation failure (16, IQR 12-18; P = 0.024). In addition, extubation failure rates decreased significantly with increasing quartiles of MRC scores (P for trend <0.001). In multivariable analysis, MRC scores ≤10 points were independently associated with extubation failure within 48 h (adjusted OR 2.131, 95% CI: 1.071-4.240, P = 0.031). CONCLUSION: Limb muscle weakness assessed on the day of extubation was found to be independently associated with higher extubation failure rates within 48 h following planned extubation in medical patients.
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Hyper-proliferation and migration of vascular smooth muscle cells (VSMCs) are closely associated with atherosclerosis. Recently, the flavonol morin has been reported to exhibit potent anti-oxidant and anti-inflammatory activities. Therefore, we investigated molecular mechanisms of morin in VSMCs stimulated by PDGF. Morin effectively inhibited PDGF-stimulated proliferation of VSMCs through a G1 cell-cycle arrest, leading to down-regulation of CDK2, CDK4, cyclin D1, and cyclin E proteins. Interestingly, PDGF markedly down-regulated p27KIP1 protein expression; however, morin treatment restored the p27KIP1expression to the basal level. Morin did not affect phosphorylation of MAPKs (ERK, p38, and JNK); however, phosphorylation of AKT was dramatically suppressed by morin in PDGF-stimulated VSMCs. Using the PI3K inhibitor, LY294002, we revealed that AKT is a key regulator in the inhibitory mechanism of morin against PDGF-induced proliferation of VSMCs. Morin disturbed migratory and invasive potential of VSMCs via suppression of matrix metalloproteinase-9 (MMP-9) activity. Using electrophoretic mobility shift assays, we verified that NF-κB, AP-1, and Sp-1 transcription factors are implicated in the mode of action of morin, which suppresses the MMP-9 activity in PDGF-induced VSMCs. Based on the results, we believe that morin may be a potential therapeutic agent for atherosclerosis without negative side effect.
Subject(s)
Cell Proliferation , Cell Movement , Cells, Cultured , Cyclin-Dependent Kinase Inhibitor p27 , Flavonoids , Matrix Metalloproteinase 9 , Muscle, Smooth, Vascular , Myocytes, Smooth Muscle , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-aktABSTRACT
BACKGROUND AND OBJECTIVE: Delirium is an important predictor of negative clinical outcomes in intensive care unit (ICU), including prolonged mechanical ventilation (MV). However, delirium has not yet proven to be directly linked to weaning difficulties. The objective of this cohort study was to evaluate the association between delirium, as observed on the day of the weaning trial, and subsequent weaning outcomes in medical patients. METHODS: This is a retrospective analysis with prospectively collected data on weaning from mechanical ventilation (MV) and delirium, as assessed by bedside ICU nurses using the Confusion Assessment Method for the ICU (CAM-ICU) between October 2011 and September 2013. RESULTS: During the study period, a total of 393 patients with MV support underwent a spontaneous breathing trial (SBT) according to the standardized protocol. Of these patients, 160 (40.7%) were diagnosed with delirium on the day of the first SBT. Patients without delirium were more successfully extubated than those with delirium (81.5% vs 69.4%, P = 0.005). Delirium was found to be associated with final weaning outcomes, including difficult (OR 1.962, 95% CI 1.201-3.205) and prolonged weaning (OR 2.318, 95% CI 1.272-4.226) when simple weaning was used as a reference category. After adjusting for potential confounding factors, delirium was still significantly associated with difficult weaning (adjusted OR 2.073, 95% CI 1.124-3.822), but not with prolonged weaning (adjusted OR 2.001, 95% CI 0.875-4.575). CONCLUSION: Delirium, as assessed by the CAM-ICU at the time of first weaning trial, was significantly associated with weaning difficulties in medical patients.
Subject(s)
Delirium/complications , Respiration, Artificial , Ventilator Weaning , Aged , Airway Extubation , Female , Humans , Intensive Care Units , Male , Middle Aged , Retrospective Studies , Treatment OutcomeABSTRACT
We demonstrate for the first time to our knowledge a dynamic measurement for an electric field sensor using a nematic liquid crystal (NLC) Fabry-Perot etalon and a wavelength-swept laser. It is well known that the wavelengths of the transmitted peaks of the NLC Fabry-Perot etalon depend on the applied electric field. The change in the effective refractive index of the NLC is measured according to the applied static electric field. The effective refractive index decreases from 1.67 to 1.51 as the applied the electric field intensity is increased. In addition, we measure the frequency of the dynamic variation in the electric field using a high-speed wavelength-swept laser. By measuring the modulation frequency of the transmitted peaks in the temporal domain, the frequency of the amplitude-modulated electric field can be estimated. The frequencies of the measured dynamic variations show a close agreement with the amplitude modulation frequencies of the induced electric field.
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OBJECTIVE: Elderly patients undergoing spinal surgery are at an increased risk of morbidity and mortality. Evaluating frailty and preoperative status is crucial for predicting postoperative outcomes. This study aimed to assess the predictive value of the modified Frailty Index (mFI), sarcopenia, Prognostic Nutritional Index (PNI), and Geriatric Nutritional Risk Index (GNRI) in determining postoperative complications in patients undergoing oblique lumbar interbody fusion (OLIF) over 60 years. METHODS: Preoperative risk factors were assessed using 11 variables, including mFI, PNI, and GNRI. Complication rates were compared among nonfrail (mFI=0; n=50), prefrail (mFI=0.09-0.18; n=144), and frail (mFI ≥0.27; n=80) patients. Demographic and perioperative variables were compared between the complication and noncomplication groups. The incidence of complications was the primary outcome measure. RESULTS: Complications occurred in 36 of 274 patients (13.1%). The frail group exhibited a significantly higher incidence of pneumonia than the nonfrail and prefrail groups. The complication group displayed significant differences in several variables, including age, fusion level, albumin level, lymphocyte count, platelet count, creatinine level, and estimated blood loss. Moreover, mFI, PNI, and GNRI differed significantly between the complication and noncomplication groups. CONCLUSIONS: MFI, PNI, and GNRI can be useful for predicting postoperative morbidity and mortality in patients undergoing OLIF. These comprehensive assessment methods enable the identification of high-risk patients and the formulation of tailored strategies to enhance postoperative outcomes. Integrating mFI, PNI, and GNRI into the preoperative evaluation process can help health care providers proactively manage high-risk patients, thus improving the overall quality of care for elderly individuals undergoing OLIF.
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Neurenteric cysts are rare and account for only 0.7%-1.3% of all spinal tumors. Spinal neurenteric cysts are associated with spina bifida, split-cord malformations, and Klippel-Feil syndrome, a rare congenital disorder characterized by fusion of two or more cervical vertebrae. Klippel-Feil syndrome is rarely accompanied by neurenteric cysts. In this case report, we describe a cervicothoracic junction neurenteric cyst associated with Klippel-Feil syndrome in a 30-year-old man who presented with a 2-month history of neck pain with radiation of pain into both arms and a 1-month history of weakness in the left arm. Magnetic resonance imaging (MRI) of the spine revealed an expansive intradural extramedullary cystic lesion anterior to the spinal cord at the cervicothoracic junction. The neurenteric cyst was removed using an anterior approach, accompanied by C5-C6 corpectomy. The patient's condition improved postoperatively, and he was discharged after postoperative MRI. Spinal neurenteric cysts should be considered in the differential diagnosis in cases of vertebral developmental abnormalities concurrent with intraspinal cysts.
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In Part II, we focus on an important aspect of spine fusion in patients with spine trauma: the pivotal role of recombinant human bone morphogenetic protein-2 (rhBMP-2). Despite the influx of diverse techniques facilitated by technological advancements in spinal surgery, spinal fusion surgery remains widely used globally. The persistent challenge of spinal pseudarthrosis has driven extensive efforts to achieve clinically favorable fusion outcomes, with particular emphasis on the evolution of bone graft substitutes. Part II of this review aims to build upon the foundation laid out in Part I by providing a comprehensive summary of commonly utilized bone graft substitutes for spinal fusion in patients with spinal trauma. Additionally, it will delve into the latest advancements and insights regarding the application of rhBMP-2, offering an updated perspective on its role in enhancing the success of spinal fusion procedures.
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The cellular and molecular mechanisms governing sexual reproduction are conserved across eukaryotes. Nevertheless, hybridization can disrupt these mechanisms, leading to asexual reproduction, often accompanied by polyploidy. In this study, we investigate how ploidy level and ratio of parental genomes in hybrids affect their reproductive mode. We analyze the gametogenesis of sexual species and their diploid and triploid hybrids from the freshwater fish family Cobitidae, using newly developed cytogenetic markers. We find that diploid hybrid females possess oogonia and oocytes with original (diploid) and duplicated (tetraploid) ploidy. Diploid oocytes cannot progress beyond pachytene due to aberrant pairing. However, tetraploid oocytes, which emerge after premeiotic genome endoreplication, exhibit normal pairing and result in diploid gametes. Triploid hybrid females possess diploid, triploid, and haploid oogonia and oocytes. Triploid and haploid oocytes cannot progress beyond pachytene checkpoint due to aberrant chromosome pairing, while diploid oocytes have normal pairing in meiosis, resulting in haploid gametes. Diploid oocytes emerge after premeiotic elimination of a single-copied genome. Triploid hybrid males are sterile due to aberrant pairing and the failure of chromosomal segregation during meiotic divisions. Thus, changes in ploidy and genome dosage may lead to cyclical alteration of gametogenic pathways in hybrids.
Subject(s)
Cypriniformes , Triploidy , Animals , Female , Male , Tetraploidy , Gametogenesis , Haploidy , Cypriniformes/geneticsABSTRACT
STUDY DESIGN: Retrospective cohort study. PURPOSE: This study aimed to investigate the effect of furosemide on prevertebral soft tissue swelling (PSTS) after anterior cervical fusion (ACF) and compare it with the effect of dexamethasone. OVERVIEW OF LITERATURE: Postoperative PSTS is a common complication of ACF. Dexamethasone has been used for its treatment; however, its efficacy remains controversial. Furosemide may reduce PSTS if it is soft tissue edema; however, no studies have demonstrated the effect of furosemide on PSTS after ACF. METHODS: The symptomatic PSTS group received intravenous (IV) administration of dexamethasone or furosemide. The asymptomatic PSTS group did not receive any medication. Patients were divided into the control (no medication, n=31), Dexa (IV dexamethasone, n=25), and Furo (IV furosemide, n=28) groups. PSTS was checked daily with simple radiographs and medication-induced reductions in PSTS from its peak or after medication. RESULTS: The peak time (postoperative days) of PSTS in the control (2.27±0.47, p<0.05) and Dexa (1.91±0.54, p<0.01) groups were significantly later than that in the Furo group (1.38±0.74). PSTS was significantly lower in the Furo group than in the Dexa group from postoperative days 4 to 7 (p<0.05). PSTS reduction after the peak was significantly greater in the Furo group than in the control (p<0.01) and Dexa (p<0.01) groups. After starting the medication therapy, the Furo group showed a significantly greater reduction in PSTS than the Dexa group (p<0.01). No difference was found in symptom improvement among the three groups. CONCLUSIONS: If furosemide is used to reduce PSTS after ACF, it can effectively reduce symptoms.
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We report a high-speed (~2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement.
Subject(s)
Filtration/instrumentation , Lasers , Refractometry/instrumentation , Transducers , Elastic Modulus , Equipment Design , Equipment Failure Analysis , Tensile StrengthABSTRACT
Kummell's disease (KD) is referred to as delayed posttraumatic vertebral collapse, avascular necrosis of vertebrae, or ischemic vertebral collapse. KD is no longer rare in an aging society. It is mainly caused by minor trauma, and nonunion occurs secondary to avascular necrosis at the vertebral body fracture site, which can lead to vertebral kyphosis or intravertebral instability. Clinical symptoms of KD range from no symptoms to severe paralysis due to nerve injury. KD is considered a complication of osteoporotic vertebral compression fractures, and conservative treatment, including osteoporosis treatment, is important. Timely interventions such as vertebral augmentation or surgery, with active regular follow-up are necessary before the onset of neurological deficits due to osteonecrotic collapse in patients with suspected KD. In this study, we summarize the pathogenesis, diagnosis, and treatment of KD, which is showing increasing prevalence in an aging society. We have presented a literature review and discussed clinical guidelines and therapeutic strategies to reduce the morbidity and mortality associated with KD.
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The use of carbon-fiber-reinforced polymers (CFRPs) for the repair and rehabilitation of reinforced concrete (RC) structures has been receiving a lot of attention. Specifically, the shear strengthening of RC members based on CFRP materials has been treated as an effective and efficient strengthening method. Previous research projects focused on the shear strengthening of RC members with unidirectional CFRP strips. Although the effectiveness of a bidirectional CFRP layout compared to a unidirectional CFRP layout was discussed in several studies, these studies only investigated the issue based on experiments. Morever, the parameters of the bidirectional CFRP layout were not clearly defined. This study investigates the performance of RC beams strengthened by bidirectional CFRP based on numerical models. A numerical model based on finite element analysis is designed. Using the numerical model, the parameters of the horizontal CFRP strips, such as the layouts of horizontal CFRP strips and the number of horizontal CFRP strips, are studied. The results show that the effect of horizontal CFRP strips is maximized if the strips are distributed along the depth. In contrast, the number of horizontal CFRP strips does not significantly affect the shear strength of RC members.
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Objective: This study aims to determine the optimal dose of recombinant-human Bone Morphogenic Protein-2 (rhBMP-2) for successful bone fusion in minimally invasive Lateral Lumbar Interbody Fusion (MIS LLIF). Previous studies show that rh-BMP is an effective alternative to autologous iliac crest bone graft, but the optimal dose remains uncertain. The study analyzes the fusion rates associated with different rh-BMP doses to provide a recommendation for the optimal dose in MIS LLIF. Methods: 93 patients underwent MIS LLIF using demineralized bone matrix (DBM) or a mixture of rhBMP-2 and DBM as fusion material. The group was divided into the following three groups according to the rhBMP-2 usage. Group A (only DBM was used, n: 27). Group B (1mg of rhBMP-2 per 5cc of DBM paste, n: 41). Group C (2mg of rhBMP-2 per 5cc of DBM paste, n: 25). Demographic data, clinical outcomes, postoperative complication and fusion were assessed. Results: At 12 months post-surgery, the overall fusion rate was 92.3% according to Bridwell fusion grading system. Group B and C, who received rhBMP-2, had significantly higher fusion rates than group A, who received only DBM. However, there was no significant increase in fusion rate when the rhBMP-2 dosage was increased from group B to group C. The group B and C showed significant improvement in back pain and ODI compared to the group A. The incidence of screw loosening was decreased in group B and C, but there was no significant difference in the occurrence of other complications. Conclusion: Usage of rhBMP-2 in LLIF surgery leads to early and increased final fusion rates, which can result in faster pain relief and return to daily activities for patients. The benefits of using rhBMP-2 were not significantly different between the groups that received 1mg/5cc and 2mg/5cc of rhBMP-2. Therefore, it is recommended to use 1mg of rhBMP-2 with 5cc of DBM, taking both economic and clinical aspects into consideration.