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Background: The purpose of this long-term (up to 17 years) follow-up study was to determine: (1) clinical results and evidence of clicking or squeaking sounds; (2) radiographic results, including rates of osseointegration, bone remodeling, and osteolysis; (3) rates of complications including thigh pain, periprosthetic fracture, and ceramic fracture; (4) rates of revision; and (5) survival rates of implants in patients younger than 30 years.Methods: We analyzed the results of 240 consecutive primary total hip arthroplasty in 180 patients (118 men and 62 women who had a mean age of 27 years (range, 21 to 30 years)). The mean follow-up was 16 years (range, 14 to 17 years).Results: Mean Harris hip score, Western Ontario and McMaster Universities score, and University of California, Los Angeles activity score were 93 points, 18 points, and 7 points, respectively, at final follow-up. Radiographically, all of the acetabular components and all but two femoral components were well-fixed at the final follow-up. No hip had osteolysis or exhibited Grade 3 stress shielding. All but two patients had no groin or thigh pain. No hip had a periprosthetic or ceramic fracture. Eight hips (3%) exhibited squeaking sounds. Two acetabular components and two femoral stems were revised. The survival of the acetabular and femoral component was 99.2% (95% confidence interval, 94 to 100%).Conclusion: The results of the present long-term study of ultra-short anatomic cementless femoral stems suggest excellent clinical and radiographic results in patients younger than 30 years. [ABSTRACT FROM AUTHOR]

Background: Short and ultra‐short implants implants supporting single crowns seem to demonstrate high percentages of survival and stable marginal bone levels at a mid‐term follow‐up. Nevertheless, insurgence of peri‐implant complications still represents a critical issue, especially for patients with history of periodontitis. Purpose: The aim of this retrospective study was to evaluate implant survival, marginal bone loss and peri‐implant complications in 333 short and ultra‐short implants, placed in periodontally healthy patients and patients with a history of periodontitis. Materials and Methods: Implants were placed in the maxillary and mandibular posterior regions of 142 patients with (PP) and without (NPP) a history of periodontitis. Clinical and radiographic examinations were performed at 5‐year recall appointments. Results: Implants respectively placed in PP and NPP were: 35.68% and 42.50% in 8.0 mm‐length group, 33.33% and 36.67% in 6.0 mm‐length group, and 30.99% and 20.83% in 5.0 mm‐length group. Implant‐based survival after 5 years of follow‐up was 95.77% for PP and 96.67% for NPP (p = 0.77). Regarding crestal bone level variations, average crestal bone loss was statistically different (p = 0.04) among PP (0.74 mm) and NPP (0.61 mm). Implants presenting signs of mucositis were 6.86% in PP and 7.76% in NPP (p = 0.76). Setting the threshold for excessive bone loss at 1 mm after 60 months, peri‐implantitis prevalence was 7.84% in PP and 2.59% in NPP (p = 0.08). Overall implant success was 92.16% and 97.41%, respectively, for PP and NPP. Conclusions: Under strict maintenance program, five‐year outcomes suggest that short and ultra‐short locking‐taper implants can be successfully restored with single crowns in the posterior jaws both in PP and NPP. [ABSTRACT FROM AUTHOR]

With increasing levels of renewable energy in power systems, the coordination of different types of dispatchable resources, such as coal-fired power plants, hydropower plants, energy storage systems, and electric vehicles, has become more important than before. To optimally dispatch these operating units, the quality of the forecasting results becomes increasingly important for the operation of power systems. In this study, an ultra-short forecasting method was proposed for photovoltaic (PV) systems. It provided a forecast of the power output for the following 5 min using sky images obtained photographically in real time. The brightness of the key area was an important factor in determining the output power of the PV system. The output power was calculated using several different features extracted from the sky images. The brightness and other key features were then processed by a bidirectional long short-term memory network. The accuracy of the proposed PV forecasting method improved the accuracy of the forecast for the total power system. A testbed system was established to capture sky images in real time and verify the effectiveness of the proposed method.

This manuscript discusses the experimental results on 300 W picosecond laser machining of aerospace-grade nickel superalloy. The effect of the laser's energetic and beam scanning parameters on the machining performance has been studied in detail. The machining performance has been investigated in terms of surface roughness, sub-surface thermal damage, and material removal rate. At optimal process conditions, a picosecond laser with an average power output of 300 W can be used to achieve a material removal rate (MRR) of ∼140 mm3/min, with thermal damage less than 20 µm. Shorter laser pulse widths increase the material removal rate and reduce the resultant surface roughness. High scanning speeds improve the picosecond laser machining performance. Edge wall taper of ∼10° was observed over all the picosecond laser machined slots. The investigation demonstrates that high-power picosecond lasers can be used for the macro-machining of industrial components at an acceptable speed and quality. [ABSTRACT FROM AUTHOR]

Background: Short and ultra‐short implants represent a predictable treatment, in terms of implant survival, with patients presenting insufficient available bone volumes. Moreover, single crown restorations represent a gold standard in terms of oral hygiene. Purpose: The aim of this retrospective study was to evaluate implant survival, marginal bone loss, and peri‐implant complications in 333 locking‐taper short and ultra‐short implants. Materials and Methods: Implants were placed in the maxillary and mandibular posterior regions of 142 patients. Clinical and radiographic examinations were performed at 5‐year recall appointments. Results: All implants placed consisted of 8.0‐, 6.0‐, and 5.0‐mm length, 38.14%, 34.53%, and 27.33%, respectively. Three hundred thirty‐two implants (one early failure) were rehabilitated with single crowns in 141 patients. In 45.48% of the implants the crown‐to‐implant ratio was ≥2, with a mean value of 1.94. Overall implant‐based survival after 5 years of follow‐up was 96.10%: 96.85%, 95.65%, and 95.60% for 8.0‐, 6.0‐, and 5.0‐mm length implants, respectively (p = 0.82). Overall patient‐based survival was 91.55%. Regarding crestal bone level variations, average crestal bone loss and apical shift of the "first bone‐to‐implant contact point" position were 0.69 and 0.01 mm, respectively. Setting the threshold for excessive bone loss at 1 mm, during the time interval from loading to follow‐up, 28 implants experienced loss of supporting bone greater than 1 mm: 19 of them (67.85%) were surgically treated with a codified surgical regenerative protocol. After 60 months, a peri‐implantitis prevalence of 5.94% was reported, with an overall implant success of 94.06%: 95.93%, 92.73%, and 93.10% for 8.0‐, 6.0‐, and 5.0‐mm length implants, respectively (p = 0.55). Conclusion: Long‐term outcomes suggest that short and ultra‐short locking‐taper implants can be successfully restored with single crowns in the posterior area of the maxilla and mandible. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study is to determine the clinical and radiographic outcomes, mortality rate, complication rate, and revision rate of this ultra-short non-anatomic cementless femoral stem in elderly patients with a femoral neck fracture.Methods: We reviewed the results of 284 total hip arthroplasties performed with an ultra-short non-anatomic cementless stem in 280 previously active patients with a mean age of 72.8 ± 13 years (range 49-83). The mean follow-up was 9.3 years (range 7-13).Results: The mean Harris Hip Score was 86 ± 14 points at final follow-up. The mean Western Ontario and McMaster Universities Osteoarthritis Index score was 24 ± 6 points at the final follow-up. The mean University of California, Los Angeles activity score was 6 points at final follow-up. Osseointegration was seen in all acetabular (100%) and in 276 femoral components (97%). Kaplan-Meier survivorship analysis revealed that the survival rate of the femoral component at 8.3 years was 97% (95% confidence interval 91-100) and that of the acetabular component was 100% (95% confidence interval 94-100) with aseptic loosening or revision as the end point.Conclusion: An ultra-short non-anatomic cementless femoral stem in patients with good bone quality (Dorr A and some Dorr type B bone) is a safe treatment for femoral neck fracture. In patients with poor bone quality (Dorr C type), the results were very poor, and use of this stem should be avoided. [ABSTRACT FROM AUTHOR]

Ultra-short pulse lasers have already proven to be an excellent tool for material processing due to confined laser-matter interaction leading to high quality, precision and thermal-damage-free surface structuring. For the technology to be a cost-efficient and suitable for the industry, continuous research on the ways how to improve the throughput, in terms of energy and time efficiencies must be done. In this work, the ultra-short pulse lasers were used to investigate the ablation efficiency of a copper target. Laser ablation efficiency was investigated by pulse energy and beam size optimisation method for various processing parameters. Also, the efficiency of material removal by bursts of ultra-short pulses was investigated. Furthermore, it was shown that high ablation efficiency led to superior ablation quality in terms of surface roughness, which both are the most critical characteristics for industry-orientated applications. [ABSTRACT FROM AUTHOR]

Lumbar disc‐displacement, Modic changes (MCs), and UTE Disc Sign (UDS) on MRI are clinically relevant spinal phenotypes that can lead to sciatica/LBP. Not all degenerated discs result in disc‐displacement, MCs and UDS, suggesting varied etiologies. Spinopelvic parameters have been implicated in various spinal disorders. Pelvic incidence (PI) is "fixed parameter" since skeletal maturity. No study has addressed disc‐displacement, MCs and UDS in context of spinopelvic parameters. Therefore, the aim of study was to determine if spinopelvic parameters are associated and predict clinically‐relevant MRI‐phenotypes. One hundred and eight population‐based subjects (mean age: 52.3 years) were recruited. Spondylolisthesis and scoliosis individuals were excluded. Lumbar lordosis (LL), PI, sacral slope (SS), and pelvic tilt (PT) were assessed on lateral plain radiographs. Disc degeneration was assessed and summated, and presence or not of disc‐displacement and MCs were noted on T2W MRI. UDS was detected on UTE. Following exclusion criteria, 95 subjects were assessed. Disc‐displacement (82.1%), MCs (52.6%), and UDS (37.9%) were associated with lower PI, SS, LL, and LL/PI index. On multivariate analyses, lower PI was significantly related to development of these MRI phenotypes (adjusted OR range:0.95‐0.92; P <.05), with critical PI value of 42° or lower exhibiting fourfold increase risk of combined phenotypes (P =.020). Of UDS discs, 39.3% had adjacent MCs and 83.6% had disc‐displacement. 87.5% of MC had directly adjacent UDS. The first study to note that PI may "predict" the development of disc‐displacement, MCs and UDS, suggesting potential sub‐variants and mechanistic susceptibility that may be grounded in spinopelvic evolution. An "evolutionary etiological pathway" of spinal phenotype development is proposed. [ABSTRACT FROM AUTHOR]

Background: Long-term result of the ultra-short anatomic cementless stem in the patients with idiopathic or ethanol-induced osteonecrosis of the femoral head has not been assessed. The aim of this study is to evaluate the long-term clinical, radiographic, computed tomography scan, and dual-energy X-ray absorptiometry scanning results, and survivorship of this specific femoral stem in patients with idiopathic or ethanol-induced femoral head osteonecrosis.Methods: Two hundred fifty-six patients (335 hips) with an average age of 49.8 years (range 20-63) were enrolled in the current study. All patients underwent dual-energy X-ray absorptiometry scanning of the acetabulum and proximal femur preoperatively and at final follow-up. Computed tomography scan was obtained in all patients at final follow-up. The mean follow-up was 14.7 years (range 13-16).Results: At final follow-up, the average Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index score, and University of California, Los Angeles activity score were 94 points, 12 points, and 8 points, respectively. Four stems (1%) underwent revision for aseptic loosening. One acetabular component (0.3%) was revised for recurrent dislocation. No hip was revised for squeaking or clicking sound. Survivorship of the femoral stem was 99.0% (95% confidence interval 94-100) and that of the acetabular component was 99.4% (95% confidence interval 95-100) at 14.7 years.Conclusion: Ultra-short proximal loading anatomic uncemented femoral stems with ceramic-on-ceramic bearings have excellent survivorship free from aseptic loosening and good clinical results at long term.Level Of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Purpose.The burden of common perinatal mental disorders (CPMD) in low-and-middle-income countries is substantially higher than high-income countries, with low levels of detection, service provision and treatment in resource-constrained settings. We describe the development of an ultra-short screening tool to detect antenatal depression, anxiety disorders and maternal suicidal ideation.Methods.A sample of 376 women was recruited at a primary-level obstetric clinic. Five depression and anxiety symptom-screening questionnaires, demographics and psychosocial risk questionnaires were administered. All participants were assessed with the Mini-International Neuropsychiatric Interview (MINI), a structured, diagnostic interview. Screening tool items were analysed against diagnostic data using multiple logistic regression and receiver operating curve (ROC) analysis.Results.The prevalence of MINI-defined major depressive episode (MDE) and/or anxiety disorders was 33%. Overall, 18% of participants expressed suicidal ideation and behaviour, 54% of these had no depression or anxiety diagnosis. Multiple logistic regression identified four screening items that were independently predictive of MDE and anxiety disorders, investigating depressed mood, anhedonia, anxiety symptoms and suicidal ideation. ROC analysis of these combined items yielded an area under the curve of 0.83 (95% CI 0.78–0.88). A cut-off score of 2 or more offered a sensitivity of 78% and specificity of 82%.Conclusion.This novel screening tool is the first measure of CPMD developed in South Africa to include depressed mood, anxiety symptoms and suicidal ideation. While the tool requires further investigation, it may be useful for the early identification of mental health symptoms and morbidity in the perinatal period.

Purpose.: The burden of common perinatal mental disorders (CPMD) in low-and-middle-income countries is substantially higher than high-income countries, with low levels of detection, service provision and treatment in resource-constrained settings. We describe the development of an ultra-short screening tool to detect antenatal depression, anxiety disorders and maternal suicidal ideation. Methods.: A sample of 376 women was recruited at a primary-level obstetric clinic. Five depression and anxiety symptom-screening questionnaires, demographics and psychosocial risk questionnaires were administered. All participants were assessed with the Mini-International Neuropsychiatric Interview (MINI), a structured, diagnostic interview. Screening tool items were analysed against diagnostic data using multiple logistic regression and receiver operating curve (ROC) analysis. Results.: The prevalence of MINI-defined major depressive episode (MDE) and/or anxiety disorders was 33%. Overall, 18% of participants expressed suicidal ideation and behaviour, 54% of these had no depression or anxiety diagnosis. Multiple logistic regression identified four screening items that were independently predictive of MDE and anxiety disorders, investigating depressed mood, anhedonia, anxiety symptoms and suicidal ideation. ROC analysis of these combined items yielded an area under the curve of 0.83 (95% CI 0.78–0.88). A cut-off score of 2 or more offered a sensitivity of 78% and specificity of 82%. Conclusion.: This novel screening tool is the first measure of CPMD developed in South Africa to include depressed mood, anxiety symptoms and suicidal ideation. While the tool requires further investigation, it may be useful for the early identification of mental health symptoms and morbidity in the perinatal period. [ABSTRACT FROM AUTHOR]

Purpose: The pathogenesis and the clinical impact of disc calcification are not well known. Utilizing ultra-short time-to-echo (UTE) magnetic resonance imaging, the UTE Disc Sign (UDS) (i.e., hypo/hyper-intense disc band) was developed and found to be more significantly related to pain and disability than the conventional T2-weighted (T2W) MRI. It has been hypothesized that the UDS may represent mineralized deposits in the disc. The following study addressed the relationship between disc calcification on plain radiographs to that of the UDS on MRI.Methods: A cross-sectional study was performed on 106 Southern Chinese subjects (50% male; mean age 52.3 years). Standing lateral plain radiographs as well as T2W and UTE MRI of L1-S1 (n = 530 discs) were performed of all subjects. Lateral radiographs were used to localize disc calcification of the lumbar spine, T2W MRI was utilized to assess disc degeneration based on a defined grading scheme, and the UTE MRI was implemented to detect the UDS (hyper- or hypo-intense band across a disc). Disc degeneration and UDS scores were summed to represent cumulative scores. Subject demographics and disability profiles (Oswestry Disability Index: ODI) were obtained.Results: Disc calcification on plain radiographs was observed in 33.9% of subjects (55.5% males; mean age 54.3 years), whereas UDS was noted in 40.5% of subjects (51.1% males; mean age 55.0 years). Of these subjects, 66.6% calcification and 74.4% UDS occurred at the three lowest lumbar levels, while multilevel calcification and UDS involved 19.4 and 39.5%, respectively. 72.2% of subjects with plain radiographic disc calcification had corresponding UDS on UTE MRI (p < 0.001). Multilevel disc calcification on plain radiographs was associated with multilevel UDS (71.4%, p < 0.001). Both the number of calcified disc levels on plain radiographs and the number of UDS levels were also significantly and positively correlated with each other (r = 0.58, p < 0.001). Subjects with disc calcification and positive UDS as well as individuals with increased disc degeneration scores on T2 W MRI were significantly older (p < 0.05). The cumulative UDS score on UTE MRI significantly correlated with worse ODI scores (r = 0.31; p = 0.001), whereas cumulative disc calcification scores on plain radiographs did not (r = 0.15; p = 0.19).Conclusions: This is the first study to compare the UDS on UTE MRI with disc calcification on plain radiographs. Disc calcification was correlated with the UDS on UTE, suggesting that the UDS may represent disc calcification. However, UTE MRI appears to be a more sensitive imaging modality in identifying subtle and unique disc changes that may not be revealed on plain radiographs or conventional MRI. This disconnect may rationalize the significant correlation of UTE with disability in comparison with the conventional imaging, further stressing its potential clinical importance. [ABSTRACT FROM AUTHOR]

Study Design. Cross-sectional. Objective. To assess the distribution of the ultra-short time-toecho (UTE) disc sign (UDS) and its association with disc degeneration, other magnetic resonance imaging (MRI) phenotypes, pain, and disability profiles. Summary of Background Data. Disc degeneration has been conventionally assessed by T2-weighted (T2W) signal intensity on MRI; however, its clinical utility has been questionable. UTE MRI assesses short T2 components. The authors have identified a new imaging biomarker on UTE--the UDS. Methods. One hundred eight subjects were recruited. T2W MRI assessed disc degeneration and other phenotypes, and T1-rho MRI values represented quantitative proteoglycan disc profiles of L1-S1. UDS was detected on UTE (i.e., hyper-/hypointense disc band). A UDS score (cumulative number of UDS levels) and T2W summated lumbar degenerated scores (cumulative disc degeneration score) were assessed. Subject demographics, chronic low back pain (LBP), and disability profiles (Oswestry Disability Index: ODI) were obtained. Results. UDS was noted in 39.8% subjects, 61.4% occurred at the lower lumbar spine and 39.5% had multilevel UDS. UDS subjects had significantly greater severity and extent of disc degeneration, and Modic changes (P<0.05). By disc levels, a higher prevalence of disc degeneration/displacement, Modic changes, and spondylolisthesis were noted in UDS discs than non-UDS discs (P<0.05). T1-rho values were also lower in UDS discs (P=0.022). The majority of UDS could not be detected on T2W. The UDS score significantly correlated with worse ODI scores (r¼0.311; P=0.001), whereas T2W cumulative disc degeneration score did not (r=0.13; P¼0.19). LBP subjects exhibited more multilevel UDS (P<0.015) but not on T2W MRI (P=0.53). The UDS score was significantly related to LBP (P=0.009), whereas T2W cumulative disc degeneration score was not (P¼0.127). Conclusion. This is the first study to report ''UDS'' in humans. UDS is a novel imaging biomarker that is highly associated with degenerative spine changes, chronic LBP, and disability than conventional T2W MRI. [ABSTRACT FROM AUTHOR]

Since the advent of breast conservation, adjuvant radiation therapy (RT) has been standard of care following breast conserving surgery (BCS). Radiation therapy following BCS has traditionally been whole breast irradiation (WBI); studies comparing breast conservation to mastectomy utilized standard fractionation WBI, which delivers treatment daily over 5 to 7 weeks (1.8-2 Gy/fraction) and was the standard for decades. More recently, multiple randomized trials have compared standard fractionation WBI to moderately hypofractionated WBI (2.66 Gy/fraction, 15-16 fractions), which allows for completion of treatment in 3 to 4 weeks. Results have demonstrated no difference in local control between these two approaches with comparable toxicity and cosmetic outcomes with long-term follow-up. As such, moderately hypofractionated WBI represents the standard of care approach for most patients with early-stage breast cancer following BCS at this time. In the past few years, ultra-hypofractionated WBI (5.2-5.7 Gy/fraction, 5 fractions) has emerged with promising outcomes; 5-year outcomes from the FAST-Forward randomized trial demonstrated noninferiority between ultra-hypofractionated WBI and moderately hypofractionated WBI. Moving forward, long-term outcomes from ultra-hypofractionated WBI studies are expected, as well as the potential for incorporating moderately hypofractionated regimens into patients requiring regional nodal irradiation following BCS. Finally, the advent of ultra-short regimens may allow clinicians to re-evaluate treatment de-intensification in early-stage breast cancer to consider radiation therapy alone following BCS in lieu of endocrine therapy., (Copyright © 2023 Elsevier Inc. All rights reserved.)

In this paper we describe a new method for the realization of two-color femtosecond radiation pulses in a seeded free-electron laser (FEL). The two-color pulses are obtained from two electron bunches and a chirped seeding laser. Compared to the previous methods based on seeded FELs, our method has the advantages of producing two-color FEL pulses with more flexible tunability both in the pulse durations and separations. Numerical simulations for the Dalian Coherent Light Source confirm that femtosecond XUV pulses with variable pulse durations and time delay can be directly generated from a chirped seed laser at 250 nm by using this technique. We also show the possibility of performing a proof-of-principle experiment of this technique based on the Shanghai Deep-Ultraviolet FEL facility. [ABSTRACT FROM AUTHOR]

Background: Ultra-short coeliac disease (USCD) is a novel celiac disease (CD) subtype limited to the duodenal bulb (D1). HLA haplotypes and flow cytometry have not been assessed yet., Aims: To compare genetic, clinical, serologic, histopathologic and inmmunophenotypic parameters between USCD and conventional celiac disease (CCD) patients., Methods: Prospective single-center study in children and adult patients undergoing duodenal biopsies on a gluten-containing diet. Biopsies for histology and flow cytometry were taken separately from D1 and distal duodenum. Biopsies in seronegative patients with celiac lymphogram were repeated after 2 years on a gluten-free diet., Results: Among 505 included patients, 127 were diagnosed with CD, of whom 7 (5.5%) showed USCD. HLADQ2 was significantly less common in USCD compared to CCD (71% vs. 95%, p 0.003). Likewise, USCD patients showed more frequent non-significant seronegativity (28% vs. 8%, p 0.07) and significantly lower titrations (7-15IU/ml) of tissue transglutaminase antibodies (tTG-IgA) (60% vs. 13%, p<0.001). Biopsies from D1 revealed significant less NK cells down-expression in USCD patients (1.4 vs. 5, p 0.04)., Conclusions: Up to 5.5% of CD patients showed USCD. A lower frequency of HLADQ2, along with less serum tTG-IgA titration and duodenal NK cell suppression, were differential features of USCD., (Copyright © 2022 Elsevier España, S.L.U. All rights reserved.)

• Elite HRV and Welltory are valid and reliable smartphone applications and can be used to monitor HRV in elite endurance athletes. • Monitoring of the stress and recovery process is crucial in the population of elite endurance athletes. • The HRV use implemented in friendly technology like smartphone applications can substantially increase the compliance of this population. Heart rate variability (HRV) has been proposed as a useful marker that can show the performance adaptation and optimize the training process in elite athletes. The development of wearable technology permits the measurement of this marker through smartphone applications. The purpose of this study is to assess the validity and reliability of short and ultra-short HRV measurements in elite cyclists using different smartphone applications. Twenty-six professional cyclists were measured at rest in supine and in seated positions through the simultaneous use of an electrocardiogram and two different smartphone applications that implement different technologies to measure HRV: Elite HRV (with a chest strap) and Welltory (photoplethysmography). Level of significance was set at p < 0.05. Compared to an electrocardiogram, Elite HRV and Welltory showed no differences neither in supine nor in seated positions (p > 0.05) and they showed very strong to almost perfect correlation levels (r = 0.77 to 0.94). Furthermore, no differences were found between short (5 min) and ultra-short (1 min) length measurements. Intraclass correlation coefficient showed good to excellent reliability and the standard error of measurement remained lower than 6%. Both smartphone applications can be implemented to monitor HRV using short- and ultra-short length measurements in elite endurance athletes. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a proposal to generate intense ultra-short free-electron laser (FEL) pulses at Shanghai deep ultraviolet FEL (SDUV-FEL) by combining the chirped pulse amplification (CPA) technique with the high-gain harmonic generation (HGHG) technique is presented. In this proposal, a frequency chirped seed pulse obtained by stretching an ultra-short laser pulse is first used to create frequency-chirped bunching at the laser harmonics in an electron beam; then the frequency chirped harmonic radiation is amplified by an energy chirped electron beam; finally the output radiation pulse which inherits the properties of the seed pulse is compressed to provide an ultra-intense ultra-short radiation pulse. The feasibility and performance of this CPA-HGHG scheme are studied with start-to-end simulations using the parameters of SDUV-FEL. The effects of frequency chirped seed pulse on different stages of FEL gain in the radiator has been studied. It is found that the beam energy chirp is not necessary to generate frequency chirped pulse in the coherent harmonic generation (CHG) regime where a short radiator with bandwidth larger than or comparable to the seed pulse is used. This makes the CPA-CHG scheme well-suited for generating intense ultra-short radiation pulse in synchrotron light sources. On the other hand, a proper energy chirp to match the frequency chirp of the seed laser is critical in CPA-HGHG scheme where a long radiator is used. Using the beam parameters at SDUV-FEL as a representative example, we show that a frequency chirped UV pulse obtained via CPA-HGHG scheme can be compressed by over one order of magnitude by an optical pulse compressor. This technique has the potential of generating ultra-intense ultra-short XUV radiation pulses directly from a commercial infrared seed laser and may open new research opportunities for strong-field physics and ultrafast sciences. [Copyright &y& Elsevier]

Our research aimed at providing methodologically strong evidence for the reliability of HRV analysis of ultra-short (10–150 s) ECGs compared to the benchmark of 300 s. Furthermore, we evaluated the retainment of HRV differences between participants with definite cardiac autonomic neuropathy (dCAN) and controls as ECG recording length was reduced to 10 s. Pre-processed ECG recordings from 11 individuals with dCAN and 76 healthy controls were used to determine SDNN, RMSSD, Low Frequency (LF) and High Frequency (HF) and assess whether the reliability of HRV features remains comparable for ultra-short ECG time series. For frequency domain analysis, the Lomb-Scargle-Periodogram (LSP) and Fast-Fourier-Transform (FFT) approaches were compared. Nonparametric areas under the curve (AUCs) were estimated to examine the overall ability of ultra-short HRV to classify dCAN from ECGs of 10–300 s. RMSSD and HF were reliable and retained significant differences between control and dCAN from ECGs down to 10 s. SDNN and LF could be considered reliable in recordings of at least 30 s. LSP and FFT yielded comparable results. Most prevalent group differences were found for LF between 60 and 300 s. RMSSD and HF were reliable HRV features showing excellent potential for the classification of dCAN from 10-s ECG strips. For recordings longer than one minute, LF proved to be reliable and yielded best discrimination results. The current research indicated that ultra-short HRV analysis has the potential to become a time-efficient and accurate diagnostic tool for dCAN in clinical practice. [ABSTRACT FROM AUTHOR]

FELiChEM is a new infrared free-electron laser (FEL) oscillator user facility in Hefei, and has achieved the first lasing at 15 μ m in June, 2019. To improve the temporal resolution for fulfilling the user demands, in this context, we propose an operation mode of generating high-power ultra-short FEL pulses by shortening the electron bunch and enhancing the FEL gain with a small cavity length detuning. The existing magnetic chicane is used to compress the electron bunch and increase its peak current. Taking the 10 μ m FEL as an example, start-to-end simulations demonstrate that the FEL power can be greatly enhanced while the pulse duration is as short as one hundred femtoseconds. An energy slit provides an additional option that can further shorten the bunch length and reduce the energy spread by cutting off the bunch head and tail. With the energy slit on, all the minor spikes inside the FEL pulse will be further suppressed and only the main spike will be preserved. [ABSTRACT FROM AUTHOR]

The aim of this retrospective study was to evaluate implant survival, marginal bone loss and peri-implant complications in 326 short and ultra-short implants. Implants were placed in the maxillary and mandibular posterior regions of 140 patients with (PP) and without (NPP) a history of periodontal disease. Clinical and radiographic examinations were performed at 3-year recall appointments. The 8.0, 6.0 and 5.0 mm-length implants placed in PP and NPP were respectively 43.75% and 38.46%, 35.10% and 34.19%, 21.15% and 27.35%; 325 implants (one early failure) were rehabilitated with single crowns in 139 patients. Overall implant survival after 3 years of follow-up was 97.55%, 98.08% and 96.61% for PP and NPP ( p = 0.46). Crestal bone level variations were not statistically different among PP and NPP; 15.41% of implants presented signs of mucositis, 14.71% and 16.67% in PP and NPP ( p = 0.64). Setting the threshold for bone loss at 2 mm after 36 months, peri-implantitis prevalence was 2.2%, 1.96% and 2.63% in PP and NPP ( p = 0.7). Overall implant success was 82.39%, 83.33% and 80.7% for PP and NPP ( p = 0.55). Short-term outcomes suggest that short and ultra-short locking-taper implants can successfully be restored with single crowns in the posterior jaws both in PP and NPP.