Biomechanical comparison of bone staple fixation methods with suture material for median sternotomy closure using 3D-printed bone models.

AIM: To compare the biomechanical properties of three different sternal closure techniques in a 3D-printed bone model of a sternum from a 30-kg dog. METHODS: Median sternotomy was performed on a total of 90 three-dimensional (3D) copies of a polycarbonate (PC) model of a sternum, generated from the CT images of the sternum of a 30-kg German Shepherd dog. Three different methods were used to repair the sternotomies: polydioxanone suture (group PDS, n = 30), stainless steel bone staples (group SS, n = 30), and nitinol bone staples (group NS, n = 30). Each repair method was tested by applying tensile force in one of three ways (longitudinally, laterally, or torsionally) resulting in a sample size of n = 10 for each repair method-loading combination. In all experiments, the loads at 1-mm and 2-mm gap formation, failure, and the displacement at the failure point were measured. RESULTS: In lateral distraction and longitudinal shear tests, NS and SS staple repairs required application of significantly greater force than PDS across all displacement criteria (1 and 2 mm). NS exhibited significantly greater failure load than PDS. In torsion tests, NS required significantly greater application of force compared to SS or PDS at all displacement criteria (1 and 2 mm) and exhibited a greater failure load than PDS. In terms of displacement at failure point, PDS suture showed more displacement than SS or NS across all experiments (laterally, longitudinally, torsionally). CONCLUSIONS: In this study, bone staples were mechanically superior to PDS suture in median sternotomy closure using 3D-printed bone model in terms of 1-mm, 2-mm displacement loads, and displacement at failure. NS had a higher failure load than PDS under lateral, longitudinal, and torsional distraction. CLINICAL RELEVANCE: These study results imply that bone staples can be considered as an alternative surgical method for median sternotomy closure in dogs.

CSF1R-mediated myeloid cell depletion shifts the ratio of motor cortical excitatory to inhibitory neurons in a multiple system atrophy model.

Motor cortical circuit functions depend on the coordinated fine-tuning of two functionally diverse neuronal populations: glutamatergic pyramidal neurons providing synaptic excitation and GABAergic interneurons adjusting the response of pyramidal neurons through synaptic inhibition. Microglia are brain resident macrophages which dynamically refine cortical circuits by monitoring perineuronal extracellular matrix and remodelling synapses. Previously, we showed that colony-stimulating factor 1 receptor (CSF1R)-mediated myeloid cell depletion extended the lifespan, but impaired motor functions of MBP29 mice, a mouse model for multiple system atrophy. In order to better understand the mechanisms underlying these motor deficits we characterized the microglial involvement in the cortical balance of GABAergic interneurons and glutamatergic pyramidal neurons in 4-months-old MBP29 mice following CSF1R inhibition for 12 weeks. Lack of myeloid cells resulted in a decreased number of COUP TF1 interacting protein 2-positive (CTIP2+) layer V pyramidal neurons, however in a proportional increase of calretinin-positive GABAergic interneurons in MBP29 mice. While myeloid cell depletion did not alter the expression of important presynaptic and postsynaptic proteins, the loss of cortical perineuronal net area was attenuated by CSF1R inhibition in MBP29 mice. These cortical changes may restrict synaptic plasticity and potentially modify parvalbumin-positive perisomatic input. Collectively, this study suggests, that the lack of myeloid cells shifts the neuronal balance toward an increased inhibitory connectivity in the motor cortex of MBP29 mice thereby potentially deteriorating motor functions.

Clinical standards for the management of adverse effects during treatment for TB.

BACKGROUND: Adverse effects (AE) to TB treatment cause morbidity, mortality and treatment interruption. The aim of these clinical standards is to encourage best practise for the diagnosis and management of AE.METHODS: 65/81 invited experts participated in a Delphi process using a 5-point Likert scale to score draft standards.RESULTS: We identified eight clinical standards. Each person commencing treatment for TB should: Standard 1, be counselled regarding AE before and during treatment; Standard 2, be evaluated for factors that might increase AE risk with regular review to actively identify and manage these; Standard 3, when AE occur, carefully assessed and possible allergic or hypersensitivity reactions considered; Standard 4, receive appropriate care to minimise morbidity and mortality associated with AE; Standard 5, be restarted on TB drugs after a serious AE according to a standardised protocol that includes active drug safety monitoring. In addition: Standard 6, healthcare workers should be trained on AE including how to counsel people undertaking TB treatment, as well as active AE monitoring and management; Standard 7, there should be active AE monitoring and reporting for all new TB drugs and regimens; and Standard 8, knowledge gaps identified from active AE monitoring should be systematically addressed through clinical research.CONCLUSION: These standards provide a person-centred, consensus-based approach to minimise the impact of AE during TB treatment.

Cuspal Shape Alterations by Bmp4 Directing Cell Proliferation and Apoptosis.

The enamel knot (EK), located at the center of cap stage tooth germs, is a transitory cluster of nondividing epithelial cells. The EK acts as a signaling center that provides positional information for tooth morphogenesis and regulates the growth of tooth cusps. To identify species-specific cuspal patterns, this study analyzed the cellular mechanisms in the EK that were related to bone morphogenetic protein (Bmp), which plays a crucial role in cell proliferation and apoptosis. To understand the cellular mechanisms in the EK, the differences between 2 species showing different cuspal patterning, mouse (pointy bunodont cusp) and gerbil (flat lophodont cusp), were analyzed with quantitative reverse transcriptase polymerase chain reaction and immunofluorescent staining. Based on these, we performed protein-soaked bead implantation on tooth germs of the 2 different EK regions and compared the cellular behavior in the EKs of the 2 species. Many genes related with cell cycle, cell apoptosis, and cell proliferation were involved in BMP signaling in the EK during tooth development. A comparison of the cell proliferation and apoptosis associated with Bmp revealed distinctive patterns of the cellular mechanisms. Our findings indicate that the cellular mechanisms, such as cell proliferation and apoptosis, in the EK are related to Bmp4 and play an important role in tooth morphogenesis.

Nanotextured CeO2-SnO2 Composite: Efficient Photocatalytic, Antibacterial, and Energy Storage Fibers.

Bacterial infections remain a serious and pervasive threat to human health. Bacterial antibiotic resistance, in particular, lowers treatment efficacy and increases mortality. The development of nanomaterials has made it possible to address issues in the biomedical, energy storage, and environmental fields. This paper reports the successful synthesis of CeO2-SnO2 composite nanofibers via an electrospinning method using polyacrylonitrile polymer. Scanning and transmission electron microscopy assessments showed that the average diameter of CeO2-SnO2 nanofibers was 170 nm. The result of photocatalytic degradation for methylene blue dye displayed enhanced efficiency of the CeO2-SnO2 composite. The addition of SnO2 to CeO2 resulted in the enhancement of the light absorption property and enriched charge transmission of photoinduced electron-hole duos, which conspicuously contributed to momentous photoactivity augmentation. Composite nanofibers exhibited higher specific capacitance which may be accredited to the synergism between CeO2 and SnO2 particles in nanofibers. Furthermore, antibacterial activity was screened against Escherichia coli and CeO2-SnO2 composite nanofibers depicted excellent activity. The findings of this work point to new possibilities as an electrode material in energy storage systems and as a visible-light-active photocatalyst for the purification of chemical and biological contaminants, which would substantially benefit environmental remediation processes.

Attosecond field emission.

Field emission of electrons underlies great advances in science and technology, ranging from signal processing at ever higher frequencies1 to imaging of the atomic-scale structure of matter2 with picometre resolution. The advancing of electron microscopy techniques to enable the complete visualization of matter on the native spatial (picometre) and temporal (attosecond) scales of electron dynamics calls for techniques that can confine and examine the field emission on sub-femtosecond time intervals. Intense laser pulses have paved the way to this end3,4 by demonstrating femtosecond confinement5,6 and sub-optical cycle control7,8 of the optical field emission9 from nanostructured metals. Yet the measurement of attosecond electron pulses has remained elusive. We used intense, sub-cycle light transients to induce optical field emission of electron pulses from tungsten nanotips and a weak replica of the same transient to directly investigate the emission dynamics in real time. Access to the temporal properties of the electron pulses rescattering off the tip surface, including the duration τ = (53 as ± 5 as) and chirp, and the direct exploration of nanoscale near fields open new prospects for research and applications at the interface of attosecond physics and nano-optics.

Regional and annual patterns in respiratory virus co-infection etiologies and antibiotic prescriptions for pediatric mycoplasma pneumoniae pneumonia.

OBJECTIVE: Mycoplasma pneumoniae (M. pneumoniae) pneumonia is the second-most common cause of community-acquired pneumonia (CAP). This study aimed at investigating into the prevalence of macrolide-resistant M. pneumoniae (MRMP) with respiratory virus co-infection and the antibiotic prescriptions in children with CAP in four provinces in Korea, and to assess the variations in the findings across regions and throughout the year. PATIENTS AND METHODS: This prospective study was conducted in 29 hospitals in Korea between July 2018 and June 2020. Among the enrolled 1,063 children with CAP, all 451 patients with M. pneumoniae underwent PCR assays of M. pneumoniae and respiratory viruses, and the presence of point mutations of residues 2063 and 2064 was evaluated. RESULTS: Gwangju-Honam (88.6%) showed the highest prevalence of MRMP pneumonia, while Daejeon-Chungcheong (71.3%) showed the lowest, although the differences in prevalence were not significant (p=0.074). Co-infection of M. pneumoniae pneumonia and respiratory virus was observed in 206 patients (45.4%), and rhinovirus co-infection (101 children; 22.2%) was the most frequent. The prevalence of MRMP pneumonia with respiratory virus co-infection and the antibiotic prescriptions differed significantly among the four provinces (p < 0.05). The monthly rate of MRMP pneumonia cases among all cases of M. pneumoniae pneumonia and tetracycline or quinolone prescriptions did not differ significantly among the four regions (trend p > 0.05) during the study period. CONCLUSIONS: The prevalence of M. pneumoniae pneumonia with virus co-infection and antibiotic prescriptions could differ according to region, although the MRMP pneumonia rate showed no difference within Korea.

Clinical standards for the dosing and management of TB drugs.

BACKGROUND: Optimal drug dosing is important to ensure adequate response to treatment, prevent development of drug resistance and reduce drug toxicity. The aim of these clinical standards is to provide guidance on 'best practice´ for dosing and management of TB drugs.METHODS: A panel of 57 global experts in the fields of microbiology, pharmacology and TB care were identified; 51 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all participants.RESULTS: Six clinical standards were defined: Standard 1, defining the most appropriate initial dose for TB treatment; Standard 2, identifying patients who may be at risk of sub-optimal drug exposure; Standard 3, identifying patients at risk of developing drug-related toxicity and how best to manage this risk; Standard 4, identifying patients who can benefit from therapeutic drug monitoring (TDM); Standard 5, highlighting education and counselling that should be provided to people initiating TB treatment; and Standard 6, providing essential education for healthcare professionals. In addition, consensus research priorities were identified.CONCLUSION: This is the first consensus-based Clinical Standards for the dosing and management of TB drugs to guide clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment to improve patient care.

Petahertz-scale spectral broadening and few-cycle compression of Yb:KGW laser pulses in a pressurized, gas-filled hollow-core fiber.

We demonstrate efficient generation of coherent super-octave pulses via a single-stage spectral broadening of a Yb:KGW laser in a single, pressurized, Ne-filled, hollow-core fiber capillary. Emerging pulses spectrally spanning over more than 1 PHz (250-1600 nm) at a dynamic range of ∼60 dB, and an excellent beam quality open the door to combining Yb:KGW lasers with modern light-field synthesis techniques. Compression of a fraction of the generated supercontinuum to intense (8 fs, ∼2.4 cycle, ∼650 µJ) pulses allows convenient use of these novel laser sources in strong-field physics and attosecond science.

Short-term neonatal and long-term infant outcome of late-preterm twins: nationwide population-based study.

OBJECTIVES: To evaluate the short- and long-term outcome of late-preterm compared with term birth in twin pregnancy. METHODS: This retrospective observational cohort study included all women who had a twin delivery between 1 January 2007 and 31 December 2010 recorded in the claims database of the Korea National Health Insurance, with at least one follow-up recorded in the database of the National Health Screening Program for Infants and Children. Outcomes were analyzed at the pregnancy level, with adverse outcome being defined as an adverse outcome in one or both twins, identified by a diagnosis according to the International Classification of Diseases 10th Revision. The primary short-term outcome was composite morbidity, which included any of the following: transient tachypnea, respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage and bronchopulmonary dysplasia. Long-term adverse outcome included any neurological or neurodevelopmental outcome, defined by prespecified neurological and developmental diagnoses; these were assessed by following up all neonates until the end of 2018, by which time they were 8-11 years of age. Outcomes were compared between twins delivered late preterm (34 + 0 to 36 + 6 weeks) and those delivered at term (≥ 37 weeks). RESULTS: Among 17 189 women who delivered twins at ≥ 34 weeks of gestation during the study period, 5032 (29.27%) women delivered in the late-preterm period. On multivariate analysis, compared with the twins delivered at term, the late-preterm twins had an increased risk for the primary short-term outcome of composite morbidity (adjusted odds ratio (aOR), 2.09; 95% CI, 1.90-2.30), including transient tachypnea (aOR, 1.85; 95% CI, 1.64-2.09), respiratory distress syndrome (aOR, 2.31; 95% CI, 2.04-2.62), necrotizing enterocolitis (aOR, 2.10; 95% CI, 1.20-3.69) and intraventricular hemorrhage (aOR, 2.13; 95% CI, 1.46-3.11). For the long-term outcome, the late-preterm twins also had an increased risk for any neurological or neurodevelopmental outcome (adjusted hazard ratio, 1.14; 95% CI, 1.07-1.21). CONCLUSIONS: Twins delivered in the late-preterm period have an increased risk for short- and long-term morbidity compared with twins delivered at term. These results should be considered when determining the timing of delivery in uncomplicated twin pregnancy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Vibration reduction during milling of highly flexible workpieces using active workpiece holder system.

The milling of highly flexible workpieces, such as thin-walled structures used in turbine blades, aerospace equipment, and jet engine compressors, requires vibration compensation to improve the quality of the workpiece surface. Vibration can be reduced by selecting appropriate cutting parameters. However, this approach reduces system productivity. This paper presents an active workpiece holder that controls the vibration of general computer numerical control machine tools. The proposed holder, which comprises a flexible guide mechanism, driver, and sensor, measures vibration and actively controls it using piezoactuators. A high-rigidity flexure mechanism was designed for the holder, and finite element method simulation and modal analysis were performed. Finally, the proposed system was fabricated, and experimental verification indicated that the system reduced vibration. The surface quality obtained using the controlled system was ∼50% better than that obtained using the uncontrolled system.

Incidence of subsequent osteoporotic fractures after distal radius fractures and mortality of the subsequent distal radius fractures: a retrospective analysis of claims data of the Korea National Health Insurance Service.

A better understanding of the features of subsequent fractures after distal radius fracture (DRF) is important for the prevention of further osteoporotic fractures. This study found that the cumulative incidence of subsequent osteoporotic fractures in South Korea increased over time and that the mortality rates of subsequent DRFs were lower than those of first-time DRFs. INTRODUCTION: We examined the incidence of osteoporotic fractures following distal radius fractures (DRFs) and the mortality rate after subsequent DRFs using claims data from the Korea National Health Insurance (KNHI) Service. METHODS: We identified records for 41,417 patients with first-time DRFs in 2012. The occurrence of osteoporotic fractures of the spine, hip, wrist, and humerus at least 6 months after the index DRF was tracked through 2016. All fractures were identified by specific diagnosis and procedure codes. One-year mortality rates and standardized mortality ratios (SMRs) for initial and subsequent DRFs were calculated for all patients. RESULTS: The 4-year cumulative incidence of all subsequent osteoporotic fractures was 14.74% (6105/41,417; 9.47% in men, 15.9% in women). The number of associated subsequent fractures was 2850 for the spine (46.68%), 2271 for the wrist (37.2%), 708 for the hip (11.6%), and 276 for the humerus (4.52%). The cumulative mortality rate 1 year after the first-time and subsequent DRF was 1.47% and 0.71%, respectively, and the overall SMR was 1.48 (95% CI: 1.37-1.61) and 0.71 (95% CI: 0.42-1.21), respectively. CONCLUSION: The cumulative incidence of osteoporotic fractures following DRFs increased over the study period and was higher among women. The cumulative mortality rates and SMRs of subsequent DRFs were lower than those of first-time DRFs at the 1-year follow-up. Given the increasing incidence rate of DRFs, the incidence of subsequent osteoporotic fractures may also increase.

Thyroid surgery during coronavirus-19 pandemic phases I, II and III: lessons learned in China, South Korea, Iran and Italy.

OBJECTIVE: We compared demographic and clinic-pathological variables related to the number of surgeries for thyroid conditions or for cancer, morbidity, and fine needle aspiration (FNA) practices among Covid19 pandemic phases I, II, III and the same seasonal periods in 2019. METHODS: The prospective database of the Division of Thyroid Surgery, China-Japan Union Hospital of Jilin University, Changchun, China was used for this study. Covid19 emergency levels were stratified according to the World Health Organization: phase I (January 25-February 25, 2020), phase II (February 26-March 19), phase III (March 20-April 20). RESULTS: There were fewer outpatient FNAs and surgeries in 2020 than in 2019. There were no thyroid surgeries during phase I. There were also fewer surgeries for cancer with a significant reduction of advanced stage cancer treatments, mainly stage T1b N1a in phase II and T3bN1b in phase III. Operative times and postoperative stays were significantly shorter during the pandemic compared to our institutional baseline. In phase III, vocal cord paralysis (VCP) increased to 4.3% of our baseline numbers (P = 0.001). There were no cases of Covid19-related complications during the perioperative period. No patients required re-admission to the hospital. CONCLUSION: The Covid19 outbreak reduced thyroid surgery patient volumes. The decrease of Covid19 emergency plans contributed to unexpected outcomes (reduction of early stage cancer treatment, decreased operative times and hospital stays, increased VCP rate).

Postpartum haemorrhage requiring transfusion and risk of cardiovascular disease later in life: a retrospective cohort study.

OBJECTIVE: To determine whether postpartum haemorrhage (PPH) is associated with cardiovascular disease (CVD), including cerebrovascular and ischaemic heart disease beyond the peripartum period. DESIGN: Population-based cohort study. SETTING: Merged databases of the Korea National Health Insurance (KNHI) claims, National Health Screening Examination and National Health Screening Program for Infants and Children. POPULATION: Women who gave birth in 2007 in the Republic of Korea and who were tracked through to 2015 for the occurrence of CVD. METHODS: Patients were identified and the occurrences of PPH and transfusion were determined using the KNHI claims database. The occurrence of CVD was tracked through 2015 using codes from the International Classification of Diseases, tenth revision (ICD-10). MAIN OUTCOME MEASURES: The risk of CVD after PPH. RESULTS: Among 150 381 women who gave birth during the study period, 9107 were diagnosed with PPH and 899 were treated with transfusion. The risk of CVD in women with PPH was no different than in women without PPH, after adjustment (HR 1.03, 95% CI 0.93-1.13). The risk of CVD in women with PPH requiring transfusion was significantly increased compared with women without PPH, after adjustment (HR 1.60, 95% CI 1.25-2.06). The risk of CVD in women with PPH without transfusion was not significantly different compared with women without PPH (HR 0.96, 95% CI 0.86-1.07). CONCLUSIONS: Postpartum haemorrhage (PPH) requiring transfusion is associated with an increased risk of CVD. Guidelines for management should be established, and further studies on the mechanisms involved should be conducted. TWEETABLE ABSTRACT: PPH requiring transfusion is associated with an increased risk of CVD.

Antimicrobial effects of three herbs (Brassica juncea, Forsythia suspensa, and Inula britannica) on membrane permeability and apoptosis in Salmonella.

AIMS: This study aimed synergistic effects of three herbs in Salmonella via increased membrane permeability and apoptosis. METHODS AND RESULTS: Using high-performance liquid chromatography, four types of phenylethyl glycosides and a lignan were detected in the herb mixture (Brassica juncea, Forsythia suspensa, and Inula britannica). During treatment with the herb mixture (1×, 2×, or 4× the MIC), viable cells decreased to 1·87 log CFU per ml (Salmonella Gallinarum) and 2·33 log CFU per ml (Salmonella Enteritidis) after 12 h of incubation according to inhibition of tricarboxylic acid cycle (P < 0·01). In addition, N-phenyl-1-naphthylamine uptake increased from 229·00 to 249·67 AU in S. Gallinarum and from 232·00 to 250·67 AU in S. Enteritidis (P < 0·05), whereas membrane potential decreased from 8855·00 to 3763·25 AU and from 8703·67 to 4300·38 AU, respectively. Apoptotic Salmonella cells were observed by confocal laser scanning microscopy and flow cytometry. Transmission electron microscopy observations with negative staining showed protein leakage from damaged Salmonella. CONCLUSIONS: These results showed the synergistic effect of the three herbs against avian pathogenic Salmonella induced by membrane damage and apoptosis. SIGNIFICANCE AND IMPACT OF THE STUDY: Salmonella causes enormous economic losses in the poultry industry. These results indicated that potency of natural antimicrobial agents due to apoptosis in Salmonella.

Exploring Relative Preferences for HIV Service Features Using Discrete Choice Experiments: a Synthetic Review.

PURPOSE OF REVIEW: Aligning HIV treatment services with patient preferences can promote long-term engagement. A rising number of studies solicit such preferences using discrete choice experiments, but have not been systematically reviewed to seek generalizable insights. Using a systematic search, we identified eleven choice experiments evaluating preferences for HIV treatment services published between 2004 and 2020. RECENT FINDINGS: Across settings, the strongest preference was for nice, patient-centered providers, for which participants were willing to trade considerable amounts of time, money, and travel distance. In low- and middle-income countries, participants also preferred collecting antiretroviral therapy (ART) less frequently than 1 monthly, but showed no strong preference for 3-compared with 6-month refill frequency. Facility waiting times and travel distances were also important but were frequently outranked by stronger preferences. Health facility-based services were preferred to community- or home-based services, but this preference varied by setting. In high-income countries, the availability of unscheduled appointments was highly valued. Stigma was rarely explored and costs were a ubiquitous driver of preferences. While present improvement efforts have focused on designs to enhance access (reduced waiting time, travel distance, and ART refill frequency), few initiatives focus on the patient-provider interaction, which represents a promising critical area for inquiry and investment. If HIV programs hope to truly deliver patient-centered care, they will need to incorporate patient preferences into service delivery strategies. Discrete choice experiments can not only inform such strategies but also contribute to prioritization efforts for policy-making decisions.

Extended approach or usage of nasoseptal flap is a risk factor for olfactory dysfunction after endoscopic anterior skullbase surgery: results from 928 patients in a single tertiary center.

BACKGROUND: The aim of this study was to compare olfactory function change in patients who underwent endoscopic skull-base surgery. METHODOLOGY: A total of 928 patients were included in this retrospective study. Olfactory function was measured using the non- validated Likert scale (0â€"100), the Cross-Cultural Smell Identification Test (CC-SIT) and the butanol threshold test (BTT). Patients were divided into two groups: an endoscopic trans-sellar approach group (ETA, n = 768) and an extended endoscopic endonasal approach group (EEEA, n = 160). The ETA group was sub-divided into Nasoseptal flap (NSF) and no NSF groups. RESULTS: Non-validated olfactory function significantly worsened in the EEEA and ETA-NSF groups compared with that in the ETA- no NSF group for at least 6 months post-operatively. Validated olfactory impairment (BTT and CC-SIT) was also significantly worse in the EEEA and NSF groups compared with that in the ETA-no NSF group 3 months post-operatively. Additionally, the degrees of non-validated and validated olfactory deterioration were not significantly different between the EEEA and ETA-NSF groups. We also found that CC-SIT score changes were significantly impaired in tuberculum sellae meningioma patients than in craniopharyn- gioma patients. CONCLUSIONS: We conclude that NSF was the key factor that led to olfactory impairment after endoscopic skull-base surgery.

Laser picoscopy of valence electrons in solids.

Valence electrons contribute a small fraction of the total electron density of materials, but they determine their essential chemical, electronic and optical properties. Strong laser fields can probe electrons in valence orbitals1-3 and their dynamics4-6 in the gas phase. Previous laser studies of solids have associated high-harmonic emission7-12 with the spatial arrangement of atoms in the crystal lattice13,14 and have used terahertz fields to probe interatomic potential forces15. Yet the direct, picometre-scale imaging of valence electrons in solids has remained challenging. Here we show that intense optical fields interacting with crystalline solids could enable the imaging of valence electrons at the picometre scale. An intense laser field with a strength that is comparable to the fields keeping the valence electrons bound in crystals can induce quasi-free electron motion. The harmonics of the laser field emerging from the nonlinear scattering of the valence electrons by the crystal potential contain the critical information that enables picometre-scale, real-space mapping of the valence electron structure. We used high harmonics to reconstruct images of the valence potential and electron density in crystalline magnesium fluoride and calcium fluoride with a spatial resolution of about 26 picometres. Picometre-scale imaging of valence electrons could enable direct probing of the chemical, electronic, optical and topological properties of materials.

Differentiation of dural arteriovenous fistula from reflux venous flow on 3D TOF-MR angiography: identifying asymmetric enlargement of external carotid artery branches.

AIM: To differentiate dural arteriovenous fistula (DAVF) from reflux venous flow (RVF) by assessment of asymmetric enlargement of external carotid artery (ECA) branches on three-dimensional (3D) time-of-flight magnetic resonance angiography (TOF-MRA). MATERIALS AND METHODS: Nineteen patients with DAVF and 27 patients with RVF were included from September 2007 to April 2019. The locations of DAVF were the cavernous (n=9) and sigmoid-transverse (n=6) sinuses, and the jugular (n=3) and sphenoparietal (n=1) veins. Two radiologists visually assessed asymmetric enlargement of the ascending pharyngeal artery (ASP), middle meningeal artery (MMA), accessory meningeal artery (AMA), artery of the foramen rotundum, and occipital artery. MMA size was also measured quantitatively. RESULTS: More frequent asymmetric enlargement of the ASP and MMA were seen in DAVF than in RVF (17 of 19 versus 3 of 27 for ASP; 16 of 19 versus 1 of 27 for MMA, p<0.01). The AMA, artery of the foramen rotundum, and occipital arteries were not visualised in RVF patients. The ipsilateral MMA size was significantly larger in DAVF than in RVF (2.14 versus 0.64 mm2, p< 0.01). The diagnostic performance of ipsilateral MMA size for DAVF was good, with an area under the receiver operating characteristic curve of 0.89, with a sensitivity of 84.2% and a specificity of 81.5% at a cut-off of 1.08 mm2. CONCLUSIONS: DAVF showed significantly larger ECA branches than RVF on 3D TOF-MRA. Therefore, thorough evaluation of ECA branches could help to differentiate DAVF from RVF.