Alamouti-coded DSP algorithm with a simplified PTBC decoder for next-generation optical access networks.

The use of Alamouti-coded polarization-time block code (A-PTBC) in combination with a simple single polarization coherent receiver enables phase-diverse coherent detection without any optical polarization tracking. However, applying this technique to high-speed single-carrier systems is not straightforward, as it requires specialized digital signal processing (DSP) algorithms for data recovery, which increases DSP complexity. In this paper, we propose a novel Alamouti-coded coherent algorithm designed to significantly reduce the complexity of the receiver DSP for data recovery. The proposed algorithm achieves the comparable performance to the conventional algorithm but requires only half the number of necessary equalizers for data recovery. We validate its performance through simulations and also experimentally demonstrate a 100 Gb/s 16-quadrature amplitude modulation (QAM) single-carrier coherent system employed the single-polarization coherent receiver over 20 km of standard single-mode fiber (SMF). Through the performance verification, the coherent system with the proposed algorithm exhibits performance comparable to that of the conventional Alamouti-coded coherent system and achieves a power budget of 34 dB when the transmit launch power is set to 7 dBm at a Bit Error Rate (BER) of 1 × 10-2 for 0-20 km fiber transmission.

Helping the Helpers: Mental Health Challenges of Psychosocial Support Workers During the Russian-Ukrainian War.

OBJECTIVE: The ongoing Russian-Ukrainian war has been linked to mental health problems in the Ukrainian general population. To date, however, scarce research has examined the mental health of psychosocial support workers (PSWs) in Ukraine who have a burdensome workload in the context of ongoing conflict. This study aimed to examine the prevalence and correlates of burnout, posttraumatic stress disorder (PTSD), and suicidal ideation (SI) in PSWs in Ukraine during the Russian-Ukrainian war. METHODS: One hundred seventy-eight PSWs in Ukraine completed a survey assessing war exposure, mental health, and psychosocial characteristics. RESULTS: A total 59.6% of PSWs screened positive for burnout, 38.2% for PTSD, and 10.7% for current SI. Lower optimism was associated with greater odds of burnout. Greater distress from witnessing war-related destruction, lower optimism, lower presence of meaning in life, and lower levels of close social relationships were associated with greater odds of burnout. Lower presence of meaning in life was associated with greater odds of SI. CONCLUSIONS: Results of this study highlight the mental health challenges faced by PSWs in Ukraine during the ongoing Russian-Ukrainian war. They further suggest that interventions to foster meaning in life and promote social connectedness may "help the helpers" during this ongoing conflict.

Functional significance of posttraumatic growth in U.S. military veterans.

BACKGROUND: Although many studies indicate that individuals who have experienced a traumatic event can experience posttraumatic growth (PTG), some researchers have questioned the significance of PTG in associations with functioning. The role of PTG in functioning following trauma may be better elucidated by accounting for its joint effects with posttraumatic stress disorder (PTSD) symptoms. METHODS: Data were analyzed from the National Health and Resilience in Veterans Study, which surveyed a nationally representative sample of 3847 trauma-exposed U.S. veterans. Participants completed assessments of potentially traumatic events, PTSD symptoms, and PTG, as well as a broad range of sociodemographic, military, trauma, health, personality, and psychosocial characteristics. RESULTS: PTG was independently and moderately associated with higher mental, cognitive, and psychosocial functioning, but not physical functioning. Results showed a similar pattern of findings when examining relations between subdomains of PTG and these aspects of functioning. Additionally, among veterans who screened positive for PTSD, those who endorsed PTG reported higher levels of mental, cognitive, and/or psychosocial functioning than those who did not endorse PTG. LIMITATIONS: Findings may be limited by the use of a cross-sectional design, retrospective self-reports of PTG, and a predominantly older white male veteran sample. CONCLUSION: Results provide support for the functional significance of PTG and highlight the importance of considering PTSD symptoms to better understand the role of PTG in functioning. Clinical interventions to foster PTG may help promote post-trauma functioning.

Intramedullary Impaction of the Basicervical Component Is Determinant of Fixation Failure in a Simple Two-Part Pertrochanteric Fracture.

OBJECTIVES: To evaluate initial fracture morphology influences on outcomes in simple 2-part pertrochanteric fracture, with a focus on the basicervical component and its initial impaction. DESIGN: A retrospective cohort series. SETTING: Single Level I Trauma Center. PATIENTS SELECTION CRITERIA: Patients older than 60 years with intertrochanteric fractures between 2011 and 2022 were retrospectively reviewed. Inclusion criteria comprised simple 2-part pertrochanteric fractures (Orthopaedic Trauma Association [OTA]/Arbetisgemeinschaftfur Osteosynthesefragen [AO] 31-A1.2) with a basicervical component who underwent cephalomedullary nailing and had a minimum follow-up of 6 months. Patients were divided whether the basicervical component was impacted into the medullary canal (intramedullary impaction [II] group) or displaced beyond the medullary canal (extramedullary [E] group). Exclusion criteria encompassed pathologic fractures, nondisplaced fractures, and basicervical neck fractures (OTA/AO 31-B3). OUTCOME MEASUREMENTS AND COMPARISONS: Reduction status was assessed as unacceptable if the head and neck (proximal) fragment was positioned intramedullary with respect to the distal fragment in either the anterior posterior or cross-lateral x-ray and acceptable otherwise. In addition, the degree of impaction on x-ray and CT scans (coronal, sagittal, axial) at injury was analyzed as a risk factor for failure. Revision rates and lag screw sliding over 15 mm were compared between the II and E groups. RESULTS: Hundred fifteen patients (95 female, average age 80 years) were included. The II group (n = 58) compared with E group (n = 57) showed more acceptable postoperative reductions (57% vs. 81%, P = 0.001), but significantly higher fixation failure (16% vs. 3.5%, P = 0.048) and fracture collapse (28% vs. 7%, P = 0.01). II was identified as a significant independent predictor for failure (odds ratio 5.64, 95% confidence interval, 2.14-16.9, P < 0.001) with more than 19.5-mm impaction in sagittal CT scan as the threshold linked to increased failure risk. CONCLUSIONS: This study highlights the significance of specific intertrochanteric fracture patterns, particularly II of a basicervical component and impaction severity (≥19.5 mm), as drivers of fixation failure. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Posttraumatic Growth in U.S. Military Veterans: Results from the National Health and Resilience in Veterans Study.

Despite increasing recognition that positive psychological changes or posttraumatic growth (PTG) may develop after highly stressful or traumatic events, contemporary population-based data on the epidemiology of PTG in high-risk samples such as U.S. military veterans are lacking. Additionally, in light of emerging evidence suggesting an 8-factor model of posttraumatic stress disorder (PTSD) symptoms, an up-to-date characterization of how these symptom clusters relate to PTG can help inform efforts to help promote PTG. Data were analyzed from the 2019-2020 National Health and Resilience in Veterans Study (NHRVS), which surveyed a nationally representative sample of 3,847 trauma-exposed U.S. veterans. Participants completed assessments of potentially traumatic events, PTSD symptoms, and PTG, as well as a broad range of sociodemographic, military, trauma, health, personality, and psychosocial characteristics. Results revealed that 63.2% of trauma-exposed veterans and 86.4% of veterans who screened positive for PTSD endorsed moderate-or-greater PTG; these prevalences are higher than those reported in an independent U.S. veteran sample in 2011 (50.1% and 72.0%, respectively). An inverted U-shaped association was observed between PTSD symptom severity and PTG levels, with scores of 31 to 51 on the PTSD Checklist for DSM-5 associated with the highest likelihood of PTG. Intrinsic religiosity and internally- and externally-generated intrusive symptoms of PTSD were identified as the strongest correlates of PTG. Results suggest that prevention and treatment efforts to mitigate severe PTSD symptoms, and help promote intrinsic religiosity, and more deliberate and organized rumination about traumatic experiences may help foster PTG in veterans.

Digital literacy among Korean older adults: A scoping review of quantitative studies.

Background: While digital literacy has become an essential competency for individuals across generations and sectors of society, supporting digital literacy in older adults is particularly challenging. South Korea is among the many countries undergoing rapid digitalization and population aging. Therefore, it is timely to identify the current understanding of digital literacy among older adults in South Korea. Aim: To identify prior studies that quantitatively measure digital literacy among older adults in South Korea and to identify and evaluate how digital literacy was measured in the reviewed studies. Methods: The study followed Arksey and O'Malley's scoping review framework, searching through four international (PubMed, CINAHL, Embase, and Cochrane Library) and four Korean (RISS, KISS, KCI, and KMBase) databases. Results: Among 42 studies included in the final analysis, 38 were cross-sectional studies, and 21 employed primary data. Digital literacy was assessed in various scopes, including digital literacy, e-health literacy, Internet use, and smartphone use. Of the 25 identified measures, three were validated; the rest varied greatly, from using a few items from large surveys to employing investigator-developed measures. Based on the European Commission's Digital Competence Framework, the most commonly addressed components were "information and data literacy" and "communication and collaboration." Conclusions: In recent years, attention toward digital literacy among South Korean older adults has grown rapidly. However, the level of digital literacy among older adults in South Korea remains inconclusive given measurement heterogeneity. Developing and validating more robust measures are warranted to evaluate digital literacy among older adults with diverse functions and circumstances.

Pandemic-related posttraumatic psychological growth in U.S. military veterans: A 3-year, nationally representative, longitudinal study.

Little is known about the positive psychological changes or posttraumatic growth (PTG) in response to the pandemic as the COVID-19 vaccines has become widely available. This longitudinal study aimed to characterize changes in the prevalence of pandemic-related PTG, and to identify and quantify the relative importance of PTG correlates pre-pandemic, 1- year peri­pandemic, and 2-years post-pandemic onset. A total of 2,441 U.S. military veterans completed Wave 3 assessment of the National Health and Resilience in Veterans Study. In the full sample, a significant decrease from peri­pandemic to 2-years post-pandemic onset was observed in overall pandemic-related PTG (41.5% to 32.2%) and four domains of PTG (appreciation of life, relating to others, personal strength, spiritual changes). Among veterans who screened positive for pandemic-related posttraumatic stress symptoms, the prevalence of pandemic-related PTG was markedly higher and did not change from peri­pandemic to 2-years post-pandemic onset (78.4% to 73.4%). Greater pre-pandemic PTG (personal strength and new possibilities) and greater worries about the effect of pandemic on one's mental health were the strongest correlates of pandemic-related PTG 2-years post-pandemic onset. Results suggest that psychosocial interventions to bolster PTG in relation to early life traumas may help facilitate PTG in response to the pandemic and related crises.

Effect of Au Nanoparticles and Scattering Layer in Dye-Sensitized Solar Cells Based on Freestanding TiO2 Nanotube Arrays.

The development of high efficiency dye-sensitized solar cells (DSSCs) has received tremendous attention. Many researchers have introduced new materials for use in DSSCs to achieve high efficiency. In this study, the change in power conversion efficiency (PCE) of DSSCs was investigated by introducing two types of materials-Au nanoparticles (Au NPs) and a scattering layer. A DSSC fabricated without neither Au NPs nor a scattering layer achieved a PCE of 5.85%. The PCE of a DSSC based on freestanding TiO2 nanotube arrays (f-TNTAs) with Au NPs was 6.50% due to better electron generation because the plasmonic absorption band of Au NPs is 530 nm, which matches the dye absorbance. Thus, more electrons were generated at 530 nm, which affected the PCE of the DSSC. The PCE of DSSCs based on f-TNTAs with a scattering layer was 6.61% due to better light harvesting by scattering. The scattering layer reflects all wavelengths of light that improve the light harvesting in the active layer in DSSCs. Finally, the PCE of DSSCs based on the f-TNTAs with Au NPs and a scattering layer was 7.12% due to the synergy of better electron generation and light harvesting by plasmonics and scattering. The application of Au NPs and a scattering layer is a promising research area for DSSCs as they can increase the electron generation and light harvesting ability.

Fast frequency discrimination and phoneme recognition using a biomimetic membrane coupled to a neural network.

In the human ear, the basilar membrane plays a central role in sound recognition. When excited by sound, this membrane responds with a frequency-dependent displacement pattern that is detected and identified by the auditory hair cells combined with the human neural system. Inspired by this structure, we designed and fabricated an artificial membrane that produces a spatial displacement pattern in response to an audible signal, which we used to train a convolutional neural network. When trained with single frequency tones, this system can unambiguously distinguish tones closely spaced in frequency. When instead trained to recognize spoken vowels, this system outperforms existing methods for phoneme recognition, including the discrete Fourier transform, zoom FFT and chirp z-transform, especially when tested in short time windows. This sound recognition scheme therefore promises significant benefits in fast and accurate sound identification compared to existing methods.

Realization of real-time DSP for C-band PAM-4 transmission in inter-datacenter network.

We designed and realized real-time pulse amplitude modulation-4 (PAM-4) digital signal processing (DSP) including forward error correction (FEC) for a C-band inter-datacenter network. The PAM-4 DSP is intended to compensate for chromatic dispersion and provide dispersion tolerance. A decision feedback equalizer (DFE) and maximum likelihood sequence equalizer (MLSE) were employed for the dispersion compensation. A low-density parity check (LDPC) code was used to increase coding gain. The soft-decision Viterbi algorithm (SOVA) was adopted to provide probabilistic information to the LDPC code. For implementation in a real-time field programmable gate arrays (FPGAs), we employed fully parallelized structures. In the design, three LDPC cores were operated in parallel, and the equalizers were also operated with 128 PAM-4 symbols. With the DSP, we empirically proved the feasibility of 25 km transmission without error-floor sign, corresponding to a dispersion compensation capacity of 425 ps/nm. We confirmed 35 km ∼ 85 km error-free transmission for inter-datacenter network.

Au-Embedded and Carbon-Doped Freestanding TiO2 Nanotube Arrays in Dye-Sensitized Solar Cells for Better Energy Conversion Efficiency.

Dye-sensitized solar cells (DSSCs) are fabricated with freestanding TiO2 nanotube arrays (TNTAs) which are incorporated with Au nanoparticles (NPs) and carbon materials via electrodeposition and chemical vapor deposition (CVD) method to create a plasmonic effect and better electron transport that will enhance their energy conversion efficiency (ECE). The ECE of DSSCs based on the freestanding TNTAs is 5.87%. The ECE of DSSCs, based on the freestanding TNTAs with Au NPs or carbon materials, is 6.57% or 6.59%, respectively, and the final results of DSSCs according to the freestanding TNTAs with Au NPs and carbon materials is increased from 5.87% to 7.24%, which is an enhancement of 23.34% owing to plasmonic effect and better electron transport. Au NPs are incorporated into the channel of freestanding TNTAs and are characterized by CS-corrected-field emission transmission electron microscope (Cs-FE-TEM) and elemental mapping. Carbon materials are also well-incorporated in the channel of freestanding TNTAs and are analyzed by Raman spectroscopy.

Dynamic control for nanostructures through slowly ramping parameters.

We propose a nanostructure control method which uses slowly ramping parameters. We demonstrate the dynamics of this method in both a nonlinear classical system and a quantum system. When a quantum mechanical two-level atom (quantum dot) is irradiated by an electric field with a slowly increasing frequency, there exists a sudden transition from ground (excited) to excited (ground) state. This occurs when the ramping rate is smaller than the square of the Rabi frequency. The transition arises when its "instant frequency"-the time derivative of the driving field phase-matches the resonance frequency, satisfying the Fermi golden rule. We also find that the parameter ramping is an efficient control manner for classical nanomechanical shuttles. For ramping of driving amplitudes, the shuttle's mechanical oscillation is amplified and even survives when the ramping is stopped outside the original oscillation region. This strange oscillation is due to the entrance into a multistable dynamic region in phase space. For ramping of driving frequencies, an onset of oscillation arises when the instant frequency enters the oscillation region. Thus, regardless of being classical or quantum, the instant frequency is physically relevant. We discuss in which conditions the dynamic control is efficient.

Physical Limits to Auditory Transduction of Hair-Cell Bundles probed by a Biomimetic System.

Inspired by auditory hair cells of lower vertebrates, we design and fabricate an opto-electro-mechanical sensor at the border of its spontaneous activity, called Hopf bifurcation critical point. As proposed for biological hair cells, we observe that, as the system approaches the critical point, the frequency selectivity and the force sensitivity are enhanced. However, we find that the enhancement has limits because of its intrinsic nonlinearity, even at the critical point. We also find that the minimally detectable force is not influenced by the active feedback force despite its enhanced sensitivity. This is due to the inevitable heating of the hair bundle, which implies that the active amplification of the hair cell bundle might not lower the threshold level of detectable sound.

Epidural anesthesia for permanent spinal cord stimulation with a cylindrical type lead: a case series.

Spinal cord stimulation (SCS) in trials involving external stimulation are easily conducted under local anesthesia. However, implantation of a permanent SCS system is painful, and can be intolerable in some patients. Epidural anesthesia can be used to perform the SCS implantation without discomfort if the patient can localize the area of paresthesia. However, little is known about epidural anesthesia for SCS. This paper reports 23 cases of permanent SCS with a cylindrical type lead implanted under the epidural anesthesia. Epidural anesthesia was sufficient in 22 patients without discomfort and significant complications. The remaining patient experienced incomplete epidural anesthesia and required additional analgesics to blunt the pain. All the leads were placed consistent with the patient's report of paresthesia area under epidural anesthesia. Thus, epidural anesthesia is an effective and safe method for the optimal placement of SCS to minimize the discomfort for patients without impairing patients' response to the intraoperative stimulation test.

Spinal cord stimulation for intractable visceral pain due to sphincter of oddi dysfunction.

Sphincter of Oddi dysfunction (SOD) is a syndrome of chronic biliary pain or recurrent pancreatitis due to the functional obstruction of the pancreaticobiliary flow. We report a case of spinal cord stimulation (SCS) for chronic abdominal pain due to SOD. The patient had a history of cholecystectomy and had suffered from chronic right upper quadrant abdominal pain. The patient had been diagnosed as having SOD. The patient was treated with opioid analgesics and nerve blocks, including a splanchnic nerve block. However, two years later, the pain became intractable. We implanted percutaneous SCS at the T5-7 level for this patient. Visual analog scale (VAS) scores for pain and the amount of opioid intake decreased. The patient was tracked for more than six months without significant complications. From our clinical case, SCS is an effective and alternative treatment option for SOD. Further studies and long-term follow-up are necessary to understand the effectiveness and the limitations of SCS on SOD.

Stripe states in photonic honeycomb ribbon.

We reveal new stripe states in deformed hexagonal array of photonic wave guides when the array is terminated to have a ribbon-shaped geometry. Unlike the well-known zero energy edge modes of honeycomb ribbon, the new one-dimensional states are shown to originate from high-energy saddle-shaped photonic bands of the ribbon's two-dimensional counterpart. We find that the strain field deforming the ribbon generates pseudo-electric fields in contrast to pseudo-magnetic fields in other hexagonal crystals. Thus, the stripe states experience Bloch oscillation without any actual electric field so that the spatial distributions of stripes have a singular dependence on the strength of the field. The resulting stripe states are located inside the bulk and their positions depend on their energies.

Epidural anesthesia for permanent spinal cord stimulation with a cylindrical type lead: a case series / 대한마취과학회지

Spinal cord stimulation (SCS) in trials involving external stimulation are easily conducted under local anesthesia. However, implantation of a permanent SCS system is painful, and can be intolerable in some patients. Epidural anesthesia can be used to perform the SCS implantation without discomfort if the patient can localize the area of paresthesia. However, little is known about epidural anesthesia for SCS. This paper reports 23 cases of permanent SCS with a cylindrical type lead implanted under the epidural anesthesia. Epidural anesthesia was sufficient in 22 patients without discomfort and significant complications. The remaining patient experienced incomplete epidural anesthesia and required additional analgesics to blunt the pain. All the leads were placed consistent with the patient's report of paresthesia area under epidural anesthesia. Thus, epidural anesthesia is an effective and safe method for the optimal placement of SCS to minimize the discomfort for patients without impairing patients' response to the intraoperative stimulation test.

Spinal Cord Stimulation for Intractable Visceral Pain Due to Sphincter of Oddi Dysfunction

Sphincter of Oddi dysfunction (SOD) is a syndrome of chronic biliary pain or recurrent pancreatitis due to the functional obstruction of the pancreaticobiliary flow. We report a case of spinal cord stimulation (SCS) for chronic abdominal pain due to SOD. The patient had a history of cholecystectomy and had suffered from chronic right upper quadrant abdominal pain. The patient had been diagnosed as having SOD. The patient was treated with opioid analgesics and nerve blocks, including a splanchnic nerve block. However, two years later, the pain became intractable. We implanted percutaneous SCS at the T5-7 level for this patient. Visual analog scale (VAS) scores for pain and the amount of opioid intake decreased. The patient was tracked for more than six months without significant complications. From our clinical case, SCS is an effective and alternative treatment option for SOD. Further studies and long-term follow-up are necessary to understand the effectiveness and the limitations of SCS on SOD.

Significance of serum antibody test for toxocariasis in healthy healthcare examinees with eosinophilia in Seoul and Gyeongsangnam-do, Korea.

There have been numerous reports on the relationship between eosinophilia and toxocariasis. The present study investigated seropositive rates of toxocariasis among healthy people with or without eosinophilia in urban and rural areas, and assessed risk factors for positive antibody test. A total of 610 healthy people, who visited health check-up (Medicheck®, Korea Association of Health Promotion), 310 from Seoul and 300 from Gyeongsangnam-do, were subjected for this study. Their serum samples were tested by ELISA with the crude antigen of Toxocara canis larvae. Cross-reactions with other tissue invading helminth antigens were also investigated. Total antibody positive rate of toxocariasis was 8.7% of the 610 subjects. When the subjects were grouped into 3 by their eosinophil counts, the antibody positive rates significantly differed by the groups; 5.9% (18/306) in the group<350/µL, 10.0% (11/110) in the group 350-500/µL, and 12.4% (24/194) in the group>500/µL (P=0.028). A total of 22 serum samples cross-reacted with other tissue-invading helminth antigens. A questionnaire analysis recognized drinking alcohol and smoking as significant risk factors of toxocariasis. In conclusion, toxocariasis antibody positive rate is correlated with eosinophil counts. It is recommended that healthy subjects with eosinophilia by routine health examination and risk factors undergo Toxocara serology by multiantigen ELISA to investigate etiology.