Proximal Junctional Kyphosis or Failure After Adult Spinal Deformity Surgery - Review of Risk Factors and Its Prevention.

Proximal junction kyphosis (PJK) is a common imaging finding after long-level fusion, and proximal junctional failure (PJF) is an aggravated form of the progressive disease spectrum of PJK. This includes vertebral fracture of upper instrumented vertebra (UIV) or UIV+1, instability between UIV and UIV+1, neurological deterioration requiring surgery. Many studies have reported on PJK and PJF after long segment instrumentation for adult spinal deformity (ASD). In particular, for spine deformity surgeons, risk factors and prevention strategies of PJK and PJF are very important to minimize reoperation. Therefore, this review aims to help reduce the occurrence of PJK and PJF by updating the latest contents of PJK and PJF by 2023, focusing on the risk factors and prevention strategies of PJK and PJF. We conducted a search on multiple database for articles published until February 2023 using the search keywords "proximal junctional kyphosis," "proximal junctional failure," "proximal junctional disease," and "adult spinal deformity." Finally, 103 papers were included in this study. Numerous factors have been suggested as potential risks for the development of PJK and PJF, including a high body mass index, inadequate postoperative sagittal balance and overcorrection, advanced age, pelvic instrumentation, and osteoporosis. Recently, with the increasing elderly population, sarcopenia has been emphasized. The quality and quantity of muscle in the surgical site have been suggested as new risk factor. Therefore, spine surgeon should understand the pathophysiology of PJK and PJF, as well as individual risk factors, in order to develop appropriate prevention strategies for each patient.

Comparison of Abdominal Muscle Thickness between the Abdominal Draw-in Maneuver and Maximum Abdominal Contraction Maneuver.

All abdominal muscles, including the transverse abdominis (TrA), should be modulated to improve core stability. This study aimed to investigate easier and more effective core exercise methods by comparing thickness changes in the TrA, internal oblique (IO), external oblique (EO), and rectus abdominis (RA) muscles during the abdominal draw-in maneuver (ADIM) and maximum abdominal contraction maneuver (MACM). Thirty healthy subjects who participated in this study underwent ADIM and MACM three times in random order. We measured the abdominal muscle thickness during ADIM and MACM using ultrasonography and compared the changes in the thickness of TrA, IO, EO, and RA muscles using a paired t-test. Significant differences were observed in the thicknesses of all the abdominal muscles between the ADIM and MACM groups (p < 0.05). The MACM immediately increased the thickness of the TrA (p < 0.001, effect size (ES) = 0.931), IO (p = 0.001, ES = 0.761), EO (p = 0.008, ES = 0.415), and RA (p < 0.001, ES = 0.767) muscles. These results suggest that MACM is useful for immediately increasing the thickness of TrA, IO, EO, and RA muscles and may contribute to the clinical effect of simultaneous contractions on the changes in abdominal muscle thickness.

Interpreting Kelvin probe force microscopy under an applied electric field: local electronic behavior of vapor-liquid-solid Si nanowires.

Kelvin probe force microscopy (KPFM) is used to characterize the electrical characteristics of vapor-liquid-solid (VLS) Si nanowires (NWs) that are grown in-place between two predefined electrodes. KPFM measurements are performed under an applied bias. Besides contact potential differences due to differing materials, the two other primary contributions to measured variations on Si NWs between electrodes are: trapped charges at interfaces, and the parallel and serial capacitance, which are accounted for with voltage normalization and oxide normalization. These two normalization processes alongside finite-element-method simulations are necessary to characterize the bias-dependent response of Si NWs. After applying both normalization methods on open-circuit NWs, which results in a baseline of zero, we conclude that we have accounted for all the major contributions to CPDs and we can isolate effects due to applied bias such as impurity states and charged carrier flow, as well as find open connections when NWs are connected in parallel. These characterization and normalization methods can also be used to determine that the specific contact resistance of electrodes to the NWs is on the order of µΩ cm². Thus, the VLS growth method between predefined electrodes overcomes the challenge of making low-resistance contacts to nanoscale systems. Thereby, the experiments and analysis presented outline a systematic method for characterizing nanowires in parallel arrays under device operation conditions.

The Effect of Motor Learning of Serial Reaction Time Task (SRTT) Through Action Observation on Mu Rhythm and Improvement of Behavior Abilities.

BACKGROUND: The aim of this study was investigate whether an action observation would have an effect on the action that requires task understanding in humans. METHODS: Participants who met the criteria for this study (n = 36). To evaluate the performance, reaction time and performance accuracy, the stimulus scheduling software was employed. For the electroencephalogram, the equipment QEEG-8 was used. RESULTS: Concerning the reaction time of the groups of different learning methods a significant difference was found after the learning among the three groups. Regarding the accuracy among the groups of different learning methods, significant difference was found in the action performance accuracy among the three groups. The relative mu power during the SRTT implementation was compared in the CZ, C3 and C4 regions before, during, and after the learning for each group. In the CZ and C4 region, a significant difference was found in the action observation group. In the C3 and C4 region a significant difference was found in the actual practice group. CONCLUSIONS: The result suggests that imitation and learning are involved even in the action that requires task understanding in humans. KEYWORDS: Accuracy; Mirror neuron system; Mu Rhythm; Reaction time; SRTT.

Selective reactions and adsorption geometries of a multifunctional molecule: cis-2-butene-1,4-diol on Si(100)-2 x 1.

The adsorption geometry of cis-2-butene-1,4-diol (BEDO, HOCH(2)CH=CHCH(2)OH) on Si(100)-2 x 1 was studied using scanning tunneling microscopy (STM), high resolution X-ray photoemission spectroscopy (XPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Bias-voltage-dependent STM images exhibited features characteristic of two distinct BEDO adsorption geometries. One feature was a bright protrusion located on the center of a single dimer, indicating an on-top configuration. The low bias-voltage STM image clearly showed dark features indicative of the formation of Si-H bonds on adjacent dimers in the same dimer row. The other feature was a bright protrusion bridged on end between two adjacent dimers in the same dimer row, indicating an end-bridge configuration. Accompanying this feature, two dark features attributed to Si-H bonds were observed on opposite positions to the bridged protrusion. From the XPS results, the Si 2p core level spectra revealed that the dimer atoms are involved in the formation of Si-O and Si-H bonds. On the other hand, carbon K-edge NEXAFS spectra showed that the C=C bond does not participate in the adsorption reaction and remains as an unreacted group. Collectively, the experimental results indicate that the adsorption of BEDO on Si(100)-2 x 1 occurs through the formation of two Si-O bonds via nucleophilic reaction between the two OH groups of BEDO and two Si-Si dimers. Importantly, the maintenance of the C=C bond means that the C=C functional group can be utilized as a new reaction site for further surface chemical reactions.

Adsorption configuration change of pyridine on Ge(100): dependence on exposure amount.

The variations of adsorption configurations of pyridine on Ge(100) as a function of exposure amount have been studied using high-resolution photoelectron spectroscopy (HRPES). At low exposure the C 1s and N 1s core levels show a single adsorption state of pyridine with N 1s binding energy at 400.85 eV and C 1s binding energies at 286.7 and 285.9 eV, respectively. Those are attributable to Ge-N dative bonding of pyridine through the lone pair electrons of its N atom, which is consistent with previous STM and theoretical studies. As the molecular exposure increases the N 1s core level reveals not only the dative-bonding state of pyridine but also the appearance of a new chemical state at 398.80 eV, corresponding to the sigma bonding of Ge-N. Such a change of adsorption configuration agrees well with new C 1s features at the low binding energy side, which accounts for the evolution of cycloaddition products with Ge-C bonds. Consequently, di-sigma-bonded cycloadducts coexist with Ge-N dative-bonding products for the final configuration with high density of pyridine on the Ge(100).

Scanning tunneling microscopy of template-stripped Au surfaces and highly ordered self-assembled monolayers.

Template stripping of Au films in ultrahigh vacuum (UHV) produces atomically flat and pristine surfaces that serve as substrates for highly ordered self-assembled monolayer (SAM) formation. Atomic resolution scanning tunneling microscopy of template-stripped (TS) Au stripped in UHV confirms that the stripping process produces a flat, predominantly 111 textured, atomically clean surface. Octanethiol SAMs vapor deposited in situ onto UHV TS Au show a c(4 x 2) superlattice with (square root 3 x square root 3) R30 degrees basic molecular structure having an ordered domain size up to 100 nm wide. These UHV results validate the TS Au surface as a simple, clean and high-quality surface preparation method for SAMs deposited from both vapor phase and solution phase.

Unidirectional Pt silicide nanowires grown on vicinal Si(100).

We investigated the structure and electronic properties of unidirectional Pt(2)Si nanowires (NWs) grown on a Si(100)-2 degrees off surface. We found that Pt(2)Si NWs were formed along the step edges of the Si(100)-2 degrees off surface with c(4x6) reconstructions that occurred on the terraces of Si(100) using scanning tunneling microscopy and the structure of formed NWs was found to be Pt(2)Si by core-level photoemission spectroscopy. Moreover, we confirmed that the electronic band structures of the NWs along the NW direction are different from those perpendicular to the NWs and the surface state induced by the Pt(2)Si NWs was observed with a small density of state using the angle-resolved photoemission spectra.

Development and psychometric testing of Korean language versions of 4 neck pain and disability questionnaires.

STUDY DESIGN: Cohort study. OBJECTIVES: To develop and establish the psychometric properties of Korean versions of 4 neck pain and disability questionnaires: the Neck Disability Index, Neck Pain and Disability Scale, Functional Rating Index, and Short Form McGill Pain Questionnaire (SFMPQ). SUMMARY OF BACKGROUND DATA: To our knowledge, there are no published Korean language neck pain and disability measures. METHODS: Versions of each questionnaire in idiomatic modern Korean were developed with a process involving initial independent translation, synthesis of the translations, independent back translation, and review by an expert committee to achieve equivalence with the original English. Psychometric testing of the questionnaires with 261 subjects was undertaken to examine test-retest reliability, internal consistency, discriminative validity, and longitudinal construct validity. RESULTS: Test-retest reliability of the translated versions of the 3 disability questionnaires was excellent (intraclass correlation coefficient[2,1] = 0.86-0.90). High internal consistency was found in the 3 disability questionnaires (Cronbach-alpha ranged from alpha = 0.88 for the Functional Rating Index to alpha = 0.96 for the Neck Pain and Disability Scale, and 0.82 for the SFMPQ). The visual analog scale subscale of the SFMPQ was the most responsive of the subscales (effect size = 1.44, standardized response mean = 1.37). The visual analog scale was also the most responsive pain and disability index in internal responsiveness analysis, although disability indexes showed marginally better responsiveness when compared with external standards. No floor or ceiling effects were observed. CONCLUSIONS: We conclude that the questionnaires were successfully translated and show acceptable measurement properties, and, as such, are suitable for use in clinical and research applications.

Chemical reactions and adsorption geometries of pyrrole on Ge(100).

The adsorption structures of pyrrole (C(4)H(5)N) on a Ge(100) surface at various coverages have been investigated with both scanning tunneling microscopy (STM) and ab initio density-functional theory (DFT) calculations. Three distinct features are observed in the STM images at low coverages. The comparison of the STM images with the simulation reveals that the most dominant flowerlike feature with a dark side is that the adsorbed pyrrole molecules with H dissociated form bridges between two down Ge atoms of neighboring Ge dimer rows through N-Ge bonding and beta-carbon-Ge interaction. The flowerlike feature without a dark side is also observed as a minority, which is identified as nearly the same structure as the most dominant one where a dissociated H is out of the feature. The third feature showing bright protrusions may be due to a C- and N-end-on (CN) configuration, where the pyrrole molecule is located on one dimer row. At higher coverages, the number of localized configurations increases.

Body chart pain location and side-specific physical impairment in subclinical neck pain.

OBJECTIVE: To test computer-using students to examine the relationship between location of neck pain as indicated on pain drawings and physical impairments compared with those subjects not reporting pain. METHODS: This cross-sectional study enrolled 81 healthy student volunteers at the College of Rehabilitation Science, Daegu University, Korea, aged 18 to 30 years. Outcomes were endurance time of neck muscles and neck range of motion (ROM) sensitization or stretch effects on repeated range tests. Active neck ROM measures were taken twice, 10 minutes apart. Neck muscle endurance time was obtained using a horizontal head-holding test with a 10-minute goal. After all physical measurements were completed, information about any neck pain was collected and 4 groups were formed on the basis of the pain location noted on the body chart. RESULTS: Sixty-seven subjects experienced recurrent neck pain. Nineteen had right-side pain, another 19 had left-side pain, 29 reported pain on both sides, and 14 did not experience neck pain. Neck muscle endurance time was significantly lower for all pain groups. For extension, left and right rotation movements at the second test, ROM decreased for subjects reporting subclinical pain and increased for those with no pain. Location of the pain to one side was related to the ROM decreased, in that the amount of reduction in the second-test rotation range was significantly greater on the side opposite to the pain. CONCLUSIONS: The location of neck pain that occurs intermittently, but is not present during range testing, affects the second test when the rotation involves stretching of tissue on the side of pain.

Proprioception and rotation range sensitization associated with subclinical neck pain.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To investigate neck proprioception, range of motion, muscle endurance, and self report of pain and disability in patients with subclinical neck pain. SUMMARY OF BACKGROUND DATA: Untreated (i.e., subclinical) neck pain represents a category intermediate between "no pain" and "treated (i.e., clinical) pain." Therefore, the features that characterize it may be targeted for early management to prevent progression. METHODS: Eighty-one healthy Korean university student volunteers, aged between 18 and 30 years (mean age, 23.2 years), were measured for proprioceptive sensitivity to differences in the extent of midrange neck retraction and rotation movements using a device that was not attached to the head; neck range of motion (twice) using the cervical range of motion device; and neck muscle endurance using a modified Biering-Sorensen test. Finally, patients were asked about any recurrent neck pain and completed Korean translations of four commonly used neck pain and disability questionnaires. RESULTS: Patients were categorized into three frequency of neck pain groups: never/infrequent, monthly, or weekly. There were significant differences between these groups on the four self-report questionnaires. Neck muscle endurance was significantly lower for the groups reporting monthly and weekly pain compared with the never/infrequent group. At the second range of motion test, increased range was obtained for patients with infrequent or no neck pain, but left rotation range of motion was less on the second test (sensitization) for patients reporting monthly and weekly pain. Movement extent discrimination was best for the group with the greatest pain frequency. CONCLUSIONS: A history of subclinical neck pain is associated with lower neck muscle endurance capacity and with less rotation range of motion on second testing but when frequent (occurring weekly or more often) is associated with greater sensitivity in judging neck movement extent. Improving strength and rotation range should therefore be investigated as targets of treatment for subclinical neck pain.

Langmuir monolayers of Co nanoparticles and their patterning by microcontact printing.

In this paper, we describe an easy and reliable method for the production of patterned monolayers of Co nanoparticles. A two-dimensional monolayer of Co nanoparticles is fabricated by spreading a nanoparticle solution over an air-water interface and then transferring it to a hydrophobic substrate by using the Langmuir-Blodgett (LB) method. Transmission electron microscopy (TEM) was used to show that, with increasing surface pressure, the Co nanoparticles become well-organized into a Langmuir monolayer with a hexagonal close-packed structure. By controlling the pH of the subphase, it was found that a monolayer of Co nanoparticles with long-range order could be obtained. Further, by transferring the Langmuir monolayer onto a poly(dimethoxysilane) (PDMS) mold, the selective micropatterning of the Co nanoparticles could be achieved on a patterned electronic circuit. The electronic transport properties of the Co nanoparticles showed the ohmic I-V curve.