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The role of hepatectomy for metastatic disease in children is controversial. Rationales include potential cure, obtaining a diagnosis, and guiding chemotherapy decisions. This study examines the safety and utility of hepatic metastasectomy for children at a single institution. After IRB approval (#22–1258), medical records were reviewed from 1995 to 2022 for children undergoing hepatic metastasectomy. En-bloc hepatectomies during primary tumor resection were excluded. Hepatic metastasectomy was performed in 16 patients for a variety of histologies. Median patient age was 12.2 years [IQR 6.9–22.6], and 13/16 patients were female (81 %). Number of hepatic metastases ranged from 1 to 23 and involved between 1 and 8 Couinaud segments. Anatomic resections included 4 hemihepatectomies and 1 sectionectomy. All other resections were nonanatomic. 3/6 resections for germ cell tumor (GCT) revealed only mature teratoma, driving adjuvant therapy decisions. When indicated, median time to adjuvant chemotherapy was 19 days [IQR 11–22]. No patients had Clavien-Dindo Class III or higher perioperative morbidity. Three patients (1 GCT, 1 adrenocortical carcinoma (ACC), and 1 gastric neuroendocrine tumor (GNET) experienced hepatic relapse. The patients with relapsed GCT and GNET are alive with disease at 17 and 135 months, respectively. The patient with ACC died of disease progression and liver failure. One patient with Wilms tumor experienced extrahepatic, retroperitoneal recurrence and died. With a median follow-up of 38 months, 10-year disease-specific and disease-free survival were 77 % and 61 %, respectively. Hepatic metastasectomy can be accomplished safely in children, may guide adjuvant therapy decisions, and is associated with long-term survival in selected patients. Level IV. Treatment Study, Case series with no comparison group. • Hepatic metastasectomy can be accomplished safely for synchronous and metachronous solid tumor liver metastases in children. • Resection of germ cell tumor liver metastases may guide adjuvant treatment decisions. • Curative-intent hepatic metastasectomy is associated with long-term survival in carefully selected patients. • Differences in underlying disease biology may predict treatment failure. [ABSTRACT FROM AUTHOR]

Long-term lithium therapy has a well-established but under-recognized association with primary hyperparathyroidism. Rates of hypercalcemia, screening for primary hyperparathyroidism, and referral for parathyroidectomy were evaluated among United States veterans on long-term lithium therapy. Patients undergoing chronic long-term lithium therapy (>12 months) were identified from 1999 to 2022. Demographics, long-term lithium therapy duration, post-treatment calcium, parathyroid hormone, creatinine, and vitamin D levels were abstracted. Rates of screening for hypercalcemia (calcium ≥10.2 mg/dL), primary hyperparathyroidism (parathyroid hormone ≥30 pg/mL in the setting of hypercalcemia), referral for parathyroidectomy, and outcomes were evaluated. A total of 1,356 patients underwent long-term lithium therapy, 514 of whom received chronic long-term lithium therapy. Baseline characteristics of patients with and without post-treatment hypercalcemia were compared. Of 148 patients with post-treatment hypercalcemia, 112 (74.7%) underwent no further evaluation for primary hyperparathyroidism, while 36 (25.3%) patients had a parathyroid hormone level recorded. Although 33 (91.7%) hypercalcemic patients screened positive for primary hyperparathyroidism, only 5 (13%) were referred for parathyroidectomy. Of the 4 patients who underwent parathyroidectomy, mean calcium was 11.2 mg/dL (range 11.1–11.4), and mean parathyroid hormone was 272 pg/mL (range 108–622). Three patients were localized on preoperative imaging, 2 of whom underwent unilateral exploration with cure, with 1 experiencing recurrence at 31 months. The remaining patient who localized preoperatively underwent bilateral exploration and had 2 ipsilateral glands resected and persistence. The patient who did not localize preoperatively underwent bilateral exploration with 3 gland resection and cure. Screening for primary hyperparathyroidism and referral for parathyroidectomy are underutilized in United States veterans undergoing chronic long-term lithium therapy. Institutional protocols to standardize screening, surveillance, and referrals to endocrinology/endocrine surgery could benefit this population at increased risk for primary hyperparathyroidism. [ABSTRACT FROM AUTHOR]

This article explores the use of artificial intelligence (AI) language models in conducting a post hoc analysis of studies comparing different surgical techniques for parastomal hernia. The researchers utilized an AI-powered chatbot to identify additional studies that may have been missed during a traditional review. However, the analysis revealed that the AI-generated citations were not legitimate and were irrelevant to the original search. This highlights the limitations of relying solely on AI for systematic reviews and emphasizes the importance of human validation. The authors caution against the dissemination of fraudulent information and stress the need for caution and external validation when using AI language models for scientific research. [Extracted from the article]

Data regarding oncologic outcomes of segmental bile duct resection (SBDR) versus pancreatoduodenectomy (PD) for bile duct cancers (BDC) are conflicting. We compared SBDR and PD for BDC utilizing pooled data analysis. A comprehensive PRISMA 2020 systematic review was performed. Studies comparing SBDR with PD for BDC were included. Pooled mean differences (MD), odds ratios (OR), and risk ratios (RR) with 95% confidence intervals (CI) were calculated. Subgroup analyses were performed. Study quality, bias, heterogeneity, and certainty were analyzed. Twelve studies from 2004 to 2021 were included, comprising 533 SBDR and 1,313 PD. SBDR was associated with positive proximal duct margins (OR 1.56; CI 1.11–2.18; P =.01), and distal duct margins (OR 43.25; CI 10.38–180.16; P <.01). SBDR yielded fewer lymph nodes (MD -6.93 nodes; CI -9.72–4.15; P <.01) and detected fewer nodal metastases (OR 0.72; CI 0.55–0.94; P =.01). SBDR portended less perioperative morbidity (OR 0.31; CI 0.21–0.46; P <.01), but not mortality (OR 0.52; CI 0.20–1.32; P =.17). SBDR was associated with locoregional recurrences (OR 1.88; CI 1.01–3.53; P =.02), and lymph node recurrences (OR 2.13; CI 1.42–3.2; P =.04). SBDR yielded decreased 5-year OS (OR 0.75; CI 0.65–0.85; P <.01). Despite decreased perioperative morbidity, SBDR appears to provide inferior oncologic control for BDC. [Display omitted] [ABSTRACT FROM AUTHOR]

Pancreatic carcinosarcoma is a rare subtype of pancreatic cancer. There are no consensus guidelines regarding its treatment. The current study is an orthogonal analysis of multiple datasets to evaluate prognostic features. A modified Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 systematic review was performed for reported cases of pancreatic carcinosarcoma. All cases of pancreatic carcinosarcoma in the National Cancer Database were identified for analysis. Analyses were compared to previously published data from the Surveillance, Epidemiology, and End Results database to increase validity. Seventy-one cases of pancreatic carcinosarcoma were reported in the literature. Reports of pancreatic carcinosarcoma increased over time (P =.0075). Tumor size >5.0 cm, metastatic disease, and relapse were associated with decreased disease-specific survival (all log-rank P <.05). Ninety-nine cases of pancreatic carcinosarcoma were analyzed within the National Cancer Database. Pancreatic carcinosarcoma incidence increased over time (P =.0371). Resection + chemotherapy, pathologic lymph node examination, and treatment at an academic center were associated with improved overall survival (all log-rank P <.05), whereas harboring ≥2 positive lymph nodes was associated with decreased overall survival (log-rank P =.0171). Within a multivariable model adjusting for age, sex, comorbid disease, and disease stage, resection + chemotherapy was associated with a decreased hazard of death (hazard ratio.036; confidence Interval.004–.298; P =.0022). Published data from the Surveillance, Epidemiology, and End Results database supported the current analysis regarding the incidence of pancreatic carcinosarcoma, resection, lymph node evaluation, and the impact of metastatic disease. Pancreatic carcinosarcoma is exceedingly rare, with a poor prognosis. Long-term survival is possible with curative resection in the absence of relapse. The number of positive lymph nodes appears to impact prognosis. [ABSTRACT FROM AUTHOR]

The utility of repeated surgical interventions in hepatoblastoma to achieve no evidence of disease (NED) is not well-defined. We examined the effect of aggressive pursuit of NED status on event-free (EFS) and overall survival (OS) in hepatoblastoma with subgroup analysis of high-risk patients. Hospital records were queried for patients with hepatoblastoma from 2005 to 2021. Primary outcomes were OS and EFS stratified by risk and NED status. Group comparisons were performed using univariate analysis and simple logistic regression. Survival differences were compared with log-rank tests. Fifty consecutive patients with hepatoblastoma were treated. Forty-one (82%) were rendered NED. NED was inversely correlated with 5-year mortality (OR 0.006; CI 0.001–0.056; P <.01). Ten-year OS (P <.01) and EFS (P <.01) were improved by achieving NED. Ten-year OS was similar between 24 high-risk and 26 not high-risk patients when NED was attained (P =.83). Fourteen high-risk patients underwent a median of 2.5 pulmonary metastasectomies, 7 for unilateral disease, and 7 for bilateral, with a median of 4.5 nodules resected. Five high-risk patients relapsed, and three were salvaged. NED status is necessary for survival in hepatoblastoma. Repeated pulmonary metastasectomy and/or complex local control strategies to obtain NED can achieve long-term survival in high-risk patients. Level III – Treatment Study - Retrospective Comparative Study. • NED status was defined as normal AFP and absence of detectable radiographic disease on interval surveillance imaging after chemotherapy, resection of the patient's primary tumor, and metastasectomy, if indicated. • NED status is necessary for survival in hepatoblastoma. • Repeated pulmonary metastasectomy and/or complex local control strategies to obtain NED benefit high-risk patients. [ABSTRACT FROM AUTHOR]

Introduction: Parastomal hernia is a debilitating complication of stoma creation. Parastomal hernia repair with mesh reduces recurrence rates in open and laparoscopic settings. Recent comparative studies conflict with previously pooled data on optimal mesh repair technique. The objective of this study is to examine parastomal hernia recurrence rates after Sugarbaker and keyhole repairs by performing an updated systematic review and meta-analysis of comparative studies. Methods: A systematic review of PubMed, MEDLINE, EMBASE, the Cochrane database, SCOPUS, and the PROSPERO registry was performed according to PRISMA 2020 guidelines (PROSPERO ID: CRD42021290483). Studies comparing parastomal hernia recurrences after Sugarbaker and keyhole repairs were included. Studies with overlapping patient cohorts (duplicate data), non-comparative studies, studies that did not report the primary outcome of interest, and studies not in the English language were excluded. Study bias was assessed using the Newcastle–Ottawa scale. Pooled mean differences (MD), odds ratios (OR), and risk ratios (RR) with 95% confidence intervals (CI) were calculated. Heterogeneity was assessed using the I2 statistic. Forest plots and funnel plots were generated. Study quality was analyzed using MINORS. Additional subgroup analysis of modern studies was performed. Results: Ten comparative studies published between 2005 and 2021 from 5 countries were included for analysis comprising 347 Sugarbaker repairs and 246 keyhole repairs. There were no differences in patient age, sex, or BMI between the groups. There was no difference between the groups regarding surgical site infection (OR 0.78; CI 0.31–1.98; P = 0.61) or post-operative bowel obstruction (OR 0.76; CI 0.23–2.56; P = 0.66). Sugarbaker repairs were significantly less often associated with parastomal hernia recurrence when compared to keyhole repairs (OR 0.38; CI 0.18–0.78; P = 0.008). There was no significant heterogeneity among the studies comparing parastomal hernia recurrence (I2 = 32%; P = 0.15). Quality analysis revealed a median MINORS score of 11 (range 6–16). Subgroup analysis of studies performed after the previously published pooled analysis (2015–2021) revealed no significant difference in parastomal hernia recurrence between the two groups (OR 0.58; CI 0.24–1.38; P = 0.22) with a significant subgroup effect (P = 0.05). Conclusions: Though there were lower rates of parastomal hernia recurrence with Sugarbaker repairs on overall analysis, this phenomenon disappeared on subgroup analysis of modern studies. Randomized controlled trials with contemporary cohorts would help further evaluate these repairs and minimize potential bias. [ABSTRACT FROM AUTHOR]

Background: Chemotherapy (CTX) is associated with improved survival for patients undergoing resection for pancreatic ductal adenocarcinoma (PDAC). The current study evaluated the influence of tumor location on receipt of CTX.Methods: The NCDB (2006-2017) was queried to identify patients with clinical stage I-III PDAC. Predictors of receipt of CTX, sequencing of CTX, and overall survival (OS) were analyzed.Results: Among 14,557 patients who underwent resection for PDAC 3,453 (24%) did not receive CTX. On multivariable analysis, patients with tail tumors were 15% less likely to receive CTX (OR 0.85, 95% CI 0.747-0.968) and 58% less likely to receive neoadjuvant CTX (OR 0.42, 95% CI 0.351-0.509) relative to patients with head/neck tumors. For patients with body tumors, there was no difference in rates of administration or sequence of CTX. For patients with resected tail tumors, median OS was 29.9 vs 18.9 months (p < 0.001) between those who did and did not receive CTX. For patients with tail tumors, independent predictors of not receiving CTX, regardless of sequence, were increasing age (OR 0.95, 95% CI 0.935-0.965), increasing post-op length of stay (OR 0.95, 95% CI 0.932-0.968), and 30-day post-op readmission (OR 0.46, 95% CI 0.315-0.670).Conclusions: In patients with clinical stage I-III PDAC, tumor location within the tail was independently associated with not receiving CTX. Given the marked improvement in OS when CTX is administered, strategies aimed at increasing the number of these patients who receive CTX are necessary. [ABSTRACT FROM AUTHOR]

Introduction: Cryoprecipitate is frequently administered as an adjunct to balanced transfusion in the setting of traumatic hemorrhage. However, civilian studies have not demonstrated a clear survival advantage, and prior observational studies noted selection bias when analyzing cryoprecipitate use. Additionally, due to the logistics involved in cryoprecipitate administration, it is inconsistently implemented alongside standardized massive transfusion protocols. This study aims to evaluate the effects of early cryoprecipitate administration on inpatient mortality in the setting of massive transfusion for exsanguinating trauma and to use propensity score analysis to minimize selection bias.Methods: The registry of an urban level 1 trauma center was queried for adult patients who received at least 6 units of packed red blood cells within 4 h of presentation. Univariate analysis, multiple logistic regression, and propensity score matching were performed.Results: 562 patients were identified. Patients with lower median RTS (6.86 (IQR 4.09-7.84) vs 7.6 (IQR 5.97-7.84), P<0.01), decreased Glasgow coma scale (12 (IQR 4-15) vs 15 (IQR 10-15), P<0.01), and increased lactate (7.5 (IQR 4.3-10.2) vs 4.9 (IQR 3.1-7.2), P<0.01) were more commonly administered cryoprecipitate. Mortality was greater among those who received cryoprecipitate (40.2% vs 23.7%, p<0.01) on univariate analysis. Neither multiple logistic regression (OR 0.917; 95% confidence interval 0.462-1.822; p = 0.805) nor propensity score matching (average treatment effect on the treated 2.3%, p = 0.77) revealed that cryoprecipitate administration was associated with a difference in inpatient mortality.Conclusions: Patients receiving cryoprecipitate within 4 h of presentation were more severely injured at presentation and had increased inpatient mortality. Multivariable logistic regression and propensity score analysis failed to show that early administration of cryoprecipitate was associated with survival benefit for exsanguinating trauma patients. The prospect of definitively assessing the utility of cryoprecipitate in exsanguinating hemorrhage warrants prospective investigation. [ABSTRACT FROM AUTHOR]

This article examines community and family life in St. Kilda, an isolated archipelago in Scotland's Western Isles. The introduction of money, tourists, and community tensions resulted in stronger family units, door locking, and an increased desire for privacy in the traditionally communitarian society.

Abstract Sclerosing Angiomatoid Nodular Transformation (SANT) of the spleen, first reported as a distinct histopathological entity in 2004, is exceedingly rare in children. The clinical progression and pathophysiologic features of this disease are poorly described in the literature. We performed a literature review of reported cases of SANT. Out of 258 reported cases, only five were in children. We present a sixth case of SANT in a four-year-old boy who presented with chronic anemia and elevated inflammatory markers. The relative variability in case presentation and the clinical concern for malignancy, warrant further disease characterization and discussion of management. [ABSTRACT FROM AUTHOR]

This article presents a novel vertical positioning stage with a dual-sensor arrangement suitable for scanning probe microscopy. The stage has a travel range of 8.4 μm and a first resonance frequency of 24 kHz in the direction of travel. The sensor arrangement consists of an integrated piezoelectric force sensor and laminated piezoresistive strain sensor. The piezoelectric force sensor exhibits extremely low noise and introduces a zero into the dynamics which allows the use of integral force feedback. This control method provides excellent damping performance and guaranteed stability. The piezoresistive sensor is used for tracking control with an analog PI controller which is shown to be an approximate inverse of the damped system. The resulting closed-loop system has a bandwidth is 11.4 kHz and 6 σ -resolution of 3.6 nm, which is ideal for nanopositioning and atomic force microscopy (AFM) applications. The proposed vertical stage is used to replace the vertical axis of a commercial AFM. Scans are performed in constant-force contact mode with a tip velocity of 0.2 mm/s, 1 mm/s and 2 mm/s. The recorded images contain negligible artefacts due to insufficient vertical bandwidth. [ABSTRACT FROM AUTHOR]

During emerging adulthood, people with attention-deficit/hyperactivity disorder (ADHD)—a disorder of self-regulation—face immense developmental challenges due to increasing demands for autonomy and self-reliance in the context of decreasing institutional and social supports. These challenges may also complicate the delivery of cognitive-behavioral treatments that have demonstrated efficacy in adults with ADHD. As such, this article highlights the implications of emerging adulthood for people with ADHD, describes common challenges in conducting skills-based treatment with these clients, and provides specific recommendations for the CBT therapist based on outcome studies, clinical literature, and clinical experience with this population. [ABSTRACT FROM AUTHOR]

Tension pneumomediastinum is a rare but life-threatening cause of tamponade. Mechanical ventilation is a described source of tension pneumomediastinum. Here, we present a case of a 72-year-old man who developed cardiovascular collapse from tension pneumomediastinum in the setting of coronavirus disease 2019–related acute respiratory distress syndrome. We successfully performed bedside mediastinotomy and mediastinal tube placement under local anesthetic to alleviate his hemodynamic instability. Bedside mediastinotomy can be used to relieve tension pneumomediastinum in this setting. [ABSTRACT FROM AUTHOR]

• Denver and Expanded Denver BCVI CTA scanning criteria miss over 30% of confirmed BCVI cases, leaving patients undiagnosed and untreated. • We advise liberal CTA scanning for any patient undergoing head and neck CT to identify BCVI cases early. • Ground level falls accounts for nearly 68% of BCVI in those ≥ 65 years of age and CTA should be obtained in this population. • Liberalized CTA scanning is safe, and immediate CTA scans at initial evaluation saves time to treatment and prevents missed BCVI diagnosis. Diagnostic Criteria Study The morbidity and mortality associated with ischemic stroke attributable to blunt cerebrovascular injury (BCVI) warrant aggressive screening. The Denver Criteria (DC) and Expanded Denver Criteria (eDC) have imprecise elements that can be difficult and subjective in application and can delay or prevent screening. We hypothesize these screening criteria lack adequate ability to consistently identify BCVI and that the use of a liberalized screening approach with CT angiography (CTA) is superior without increasing risk of acute kidney injury (AKI). This was a multi-institutional retrospective cohort study of trauma patients who presented between 2015-2020 with radiographically confirmed BCVI diagnosed using each institutions' liberalized screening protocol, defined as automatic CTA of the head and neck for all patients undergoing head and neck CT. Outcomes of interest included AKI, stroke, and death due to BCVI. Outcomes were reported as frequency, percent, and 95% confidence interval as calculated by the Clopper-Pearson method. Incidence of medical follow-up within 1 year of first medical visit was quantified as the median and inter-quartile range of days to follow-up visit. We identified 433 BCVI patients with a mean age of 45.2 (standard deviation 18.9) years, 256 men and 177 women, 1.73 m (0.10) tall, and weighed 80.3 kg (20.3). Forty-one patients had strokes (9.5% [95% confidence interval 6.9, 12.6] and 12 patients (2.8% [1.4, 4.5]) had mortality attributable to BCVI. Of 433 total cases, 132 (30.5% [26.2, 35.1]) would have been missed by DC and 150 (34.6% [30.2, 39.3]) by eDC. Incidence of AKI in our BCVI population was 6 (1.4% [0.01, 3.0]). BCVI would be missed over 30% of the time using the DC and eDC compared to liberalized use of screening CTA. Risk of AKI due to CTA did not occur at a clinically meaningful level, supporting liberal CTA screening. [ABSTRACT FROM AUTHOR]

The resolution is a critical performance metric of precision mechatronic systems such as nanopositioners and atomic force microscopes. However, there is not presently a strict definition for the measurement or reporting of this parameter. This article defines resolution as the smallest distance between two non-overlapping position commands. Methods are presented for simulating and predicting resolution in both the time and frequency domains. In order to simplify resolution measurement, a new technique is proposed which allows the resolution to be estimated from a measurement of the closed-loop actuator voltage. Simulation and experimental results demonstrate the proposed techniques. The paper concludes by comparing the resolution benefits of new control schemes over standard output feedback techniques. [ABSTRACT FROM AUTHOR]

Martin Martin wrote Voyage to St Kilda, an detailed anthropological study of a small community, in 1698. The St Kilda group of islands are west north west of North Uist in the Western Isles of Scotland, and Hirta is the only habitable island. The Voyage pre-dates the re-population of Hirta from Skye and Harris following a smallpox epidemic in 1727. Skye, Harris and Hirta were all part of the MacLeod chiefdom, and Martin's Description of the Western Isles (1703), shows how similar the life of the St Kildans was to those of their neighbours.

Abstract: Organosolv lignin was chemically modified with boron-containing reagents using a novel “graft-to” approach. The newly synthesized graft copolymers were prepared by covalently linking boron end-functionalized polycaprolactone (PCL) macromolecular reagents with organosolv lignin via reversible covalent bonds. Using a combination of 1H, 13C, 19F, and 11B NMR, it has been shown that arylboronate ester bonds are involved in the key linkages between the polyester grafts and the lignin core. Using a straightforward synthetic procedure and altering both the PCL graft density and the PCL molecular weight, a selection of compositions were studied. The newly prepared lignin-g-PCL copolymers were analyzed by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The Lignin-PCL5200 series shows an increase in PCL crystallinity with an increase PCL graft density. However, the crystallinity of the PCL in the lignin-g-PCL9100 set of materials remained constant throughout the series. TGA analysis for all lignin-g-PCL copolymers prepared herein show thermal decomposition near 300 °C. [Copyright &y& Elsevier]

Megaphyll leaf evolution was a critical event in Earth history that had major consequences for the biotic regulation of the global environment. Zimmermann''s telome theory has been widely accepted for over seventy years as the leading explanation for this evolutionary innovation. According to the telome theory, megaphylls evolved from the three-dimensional lateral branches of early vascular land plants in a hypothetical series of three transformations; first, the formation of determinate lateral branches (overtopping); second, the development of ‘flattened’ branch systems (planation); and third, the fusion of planated branches with lateral outgrowths of photosynthetic mesophyll tissue to form the leaf blade (webbing). A critical review of the molecular and cellular evidence identifies plausible genetic, cellular and physiological mechanisms in extant higher plants for overtopping and planation but more limited evidence for the process of webbing (lateral outgrowth fusion). We highlight key outstanding questions concerning the telome theory that are likely to be resolved when gene identification and functional analysis techniques are applied to photosynthetic organisms that have different evolutionary histories. [Copyright &y& Elsevier]

The flow of signalling molecules across a field of cells to generate a pattern that is then transduced into a differential response in those cells is a fundamental concept in developmental biology. Recent studies have identified a system that regulates the flux of the growth factor auxin through plant tissues via the subcellular asymmetric localization of specific transporters. The recurrent use of this auxin transport system in different developmental and physiological contexts reveals a fundamental mechanism underpinning organogenesis, stem cell positioning and the growth response of the plant to the environment. Here, I will discuss key advances in the identification of auxin transporters and their integration with auxin signal transduction pathways. [Copyright &y& Elsevier]

Leaves are made in an iterative pattern by the shoot apical meristem. The mechanism of this pattern formation has fascinated biologists, mathematicians and poets for centuries. Over the past year, fundamental insights into the molecular basis of this process have been gained. Patterns of auxin polar transport dictate when and where new leaf primordia are formed on the surface of the apical meristem. Subsequent events are still obscure but appear to involve both alteration of cell wall characteristics (to facilitate a new vector of growth) and a cascade of spatially co-ordinated transcription factor activity (to determine the fate of cells that are incorporated into new lateral organs). The co-ordinated signalling events involved in these processes are beginning to be elucidated. [Copyright &y& Elsevier]

Synthetic Aperture Radar (SAR) imagery is the primary data type used for sea ice mapping due to its spatiotemporal coverage and the ability to detect sea ice independent of cloud and lighting conditions. Automatic sea ice detection using SAR imagery remains problematic due to the presence of ambiguous signal and noise within the image. Conversely, ice and water are easily distinguishable using multispectral imagery (MSI), but in the polar regions the ocean's surface is often occluded by cloud or the sun may not appear above the horizon for many months. To address some of these limitations, this paper proposes a new tool trained using concurrent multispectral Visible and SAR imagery for sea Ice Detection (ViSual_IceD). ViSual_IceD is a convolution neural network (CNN) that builds on the classic U-Net architecture by containing two parallel encoder stages, enabling the fusion and concatenation of MSI and SAR imagery containing different spatial resolutions. The performance of ViSual_IceD is compared with U-Net models trained using concatenated MSI and SAR imagery as well as models trained exclusively on MSI or SAR imagery. ViSual_IceD outperforms the other networks, with a F1 score 1.30% points higher than the next best network, and results indicate that ViSual_IceD is selective in the image type it uses during image segmentation. Outputs from ViSual_IceD are compared to sea ice concentration products derived from the AMSR2 Passive Microwave (PMW) sensor. Results highlight how ViSual_IceD is a useful tool to use in conjunction with PMW data, particularly in coastal regions. As the spatial-temporal coverage of MSI and SAR imagery continues to increase, ViSual_IceD provides a new opportunity for robust, accurate sea ice coverage detection in polar regions. • ViSual_IceD is a convolutional neural network (CNN) trained for sea ice detection. • The CNN inputs multispectral and radar images outperforming single image tools. • The network selects the most informative image type during segmentation. • Network outputs are more accurate than coastal AMSR2 sea ice concentration data. [ABSTRACT FROM AUTHOR]

Accurate quantification of iceberg populations is essential to inform estimates of Southern Ocean freshwater and heat balances as well as shipping hazards. The automated operational monitoring of icebergs remains challenging, largely due to a lack of generality in existing approaches. Previous efforts to map icebergs have often exploited synthetic aperture radar (SAR) data but the majority are designed for open water situations, require significant operator input, and are susceptible to the substantial spatial and temporal variability in backscatter that characterises SAR time-series. We propose an adaptive unsupervised classification procedure based on Sentinel 1 SAR data and a recursive Dirichlet Process implementation of Bayesian Gaussian Mixture Model. The approach is robust to inter-scene variability and can identify icebergs even within complex environments containing mixtures of open water, sea ice and icebergs of various sizes. For the study area in the Amundsen Sea Embayment, close to the calving front of Thwaites Glacier, our classifier achieved a mean pixel-wise F1 score against manual iceberg delineations from the SAR scenes of 0. 960 ± 0. 018 with a corresponding object-level F1 score of 0. 729 ± 0. 086. The method provides an excellent basis for estimation of total near-shore iceberg populations and has inherent potential for scalability that other approaches lack. [Display omitted] • Unsupervised method as basis for scalable operational iceberg monitoring and tracking. • Icebergs reliably segmented within open water, sea ice and adjacent to calving fronts. • Adaptive method accounts for inter-scene variability without prior knowledge. [ABSTRACT FROM AUTHOR]

Abstract: The Landsat Image Mosaic of Antarctica (LIMA) is the first true-color, high-spatial-resolution image of the seventh continent. It is constructed from nearly 1100 individually selected Landsat-7 ETM+ scenes. Each image was orthorectified and adjusted for geometric, sensor and illumination variations to a standardized, almost seamless surface reflectance product. Mosaicing to avoid clouds produced a high quality, nearly cloud-free benchmark data set of Antarctica for the International Polar Year from images collected primarily during 1999–2003. Multiple color composites and enhancements were generated to illustrate additional characteristics of the multispectral data including: the true appearance of the surface; discrimination between snow and bare ice; reflectance variations within bright snow; recovered reflectance values in regions of sensor saturation; and subtle topographic variations associated with ice flow. LIMA is viewable and individual scenes or user defined portions of the mosaic are downloadable at http://lima.usgs.gov. Educational materials associated with LIMA are available at http://lima.nasa.gov. [Copyright &y& Elsevier]

Soft robots have been developed for a variety of applications including gripping, locomotion, wearables and medical devices. For the majority of soft robots, actuation is performed using pneumatics or hydraulics. Many previous works have addressed the modeling of these fluid-driven soft robots using static finite element simulations where the pressure inside the actuator is assumed to be constant and uniform. The assumption of constant internal pressure is a useful simplification but introduces significant errors during events such as pressurization, depressurization, and transient loads from a liquid environment. Applications that use soft actuators for locomotion or propulsion operate using a sequence of transient events, so accurate simulation of these events is critical to optimizing performance. To improve the simulation of soft fluidic actuators and enable the modeling of both internal and external fluid flow in underwater applications, this work describes a fully-coupled, three-dimensional fluid–structure interaction simulation approach, where the pressure and flow dynamics are explicitly solved. This approach provides a realistic simulation of soft actuators in fluid environments, and permits the optimization of transient responses, which may be due to a combination of environmental fluid loads and non-uniform pressurization. The proposed methods are demonstrated in a number of case studies and experiments for a range of actuation and both internal and external inlet flow configurations, including bending actuators, a soft robotic fish fin for propulsion, and experimental results of a bending actuator in a high-speed fluid, which correlate closely with simulations. The proposed approach is expected to assist in the design, modeling, and optimization of bioinspired soft robots in underwater applications. [Display omitted] • 3D fluid–structure interaction simulations (FSI) for soft fluidic actuators are developed. • This approach is used to model both internal and external flow and pressure dynamics. • Realistic simulation of soft actuators in fluid environments such as underwater. • A series of comparison experiments and FSI analysis are presented and discussed. [ABSTRACT FROM AUTHOR]

The mechanism of stomatal function (control of gas flux through the plant surface via regulation of pore size) is fundamentally mechanical. The material properties of the pore-forming guard cells must play a key role in setting the dynamics and degree of stomatal opening/closure, but our understanding of the molecular players involved and resultant mechanical performance has remained limited. The application of indentation techniques and computational modelling, combined with molecular tools for imaging and manipulating guard cells and their constituent cell walls, has opened the way to a systems approach to analysing this problem. The outcomes of these investigations have led to a reassessment of accepted paradigms and are providing a new understanding of the mechanism of stomatal mechanics. [ABSTRACT FROM AUTHOR]

The thermal infrared portion of the electromagnetic spectrum has considerable potential for mineral and lithological mapping of the most abundant rock-forming silicates that do not display diagnostic features at visible and shortwave infrared wavelengths. Lithological mapping using visible and shortwave infrared hyperspectral data is well developed and established processing chains are available, however there is a paucity of such methodologies for hyperspectral thermal infrared data. Here we present a new fully automated processing chain for deriving lithological maps from hyperspectral thermal infrared data and test its applicability using the first ever airborne hyperspectral thermal data collected in the Antarctic. A combined airborne hyperspectral survey, targeted geological field mapping campaign and detailed mineralogical and geochemical datasets are applied to small test site in West Antarctica where the geological relationships are representative of continental margin arcs. The challenging environmental conditions and cold temperatures in the Antarctic meant that the data have a significantly lower signal to noise ratio than is usually attained from airborne hyperspectral sensors. We applied preprocessing techniques to improve the signal to noise ratio and convert the radiance images to ground leaving emissivity. Following preprocessing we developed and applied a fully automated processing chain to the hyperspectral imagery, which consists of the following six steps: (1) superpixel segmentation, (2) determine the number of endmembers, (3) extract endmembers from superpixels, (4) apply fully constrained linear unmixing, (5) generate a predictive classification map, and (6) automatically label the predictive classes to generate a lithological map. The results show that the image processing chain was successful, despite the low signal to noise ratio of the imagery; reconstruction of the hyperspectral image from the endmembers and their fractional abundances yielded a root mean square error of 0.58%. The results are encouraging with the thermal imagery allowing clear distinction between granitoid types. However, the distinction of fine grained, intermediate composition dykes is not possible due to the close geochemical similarity with the country rock. [ABSTRACT FROM AUTHOR]

Abstract: Expansins have long been implicated in the control of cell wall extensibility. However, despite ample evidence supporting a role for these proteins in the endogenous mechanism of plant growth, there are also examples in the literature where the outcome of altered expansin gene expression is difficult to reconcile with a simplistic causal linkage to growth promotion. To investigate this problem, we report on the analysis of transgenic Arabidopsis plants in which a heterologous cucumber expansin can be inducibly overexpressed. Our results indicate that the effects of expansin expression on growth depend on the degree of induction of expansin expression and the developmental pattern of organ growth. They support the role of expansin in directional cell expansion. They are also consistent with the idea that excess expansin might itself impede normal activities of cell wall modifications, culminating in both growth promotion and repression depending on the degree of expression. [Copyright &y& Elsevier]

This article describes a monolithic nanopositioner constructed from in-plane bending actuators which provide greater deflection than previously reported extension actuators, at the expense of stiffness and resonance frequency. The proposed actuators are demonstrated by constructing an XY nanopositioning stage with a serial kinematic design. Analytical modeling and finite-element-analysis accurately predicts the experimental performance of the nanopositioner. A 10 μ m range is achieved in the X and Y axes with an applied voltage of +/-200 V. The first resonance mode occurs at 250 Hz in the Z axis. The stage is demonstrated for atomic force microscopy imaging. [ABSTRACT FROM AUTHOR]