bluuebunny/crossref_metadata_2025 huggingface dataset:
The design of a new type coaxial multilayer rotor helicopter vehicle
Authors: Ma Y H , Shieh T H , Hung L C , Tsai L C
Published: October 2022

Today’s small rotor helicopter vehicles mostly use electric motors and batteries as power sources. Most helicopter power configurations are either front powered or rear powered, causing the center of the helicopter to be offset. This kind of offset should be overcome by structural compensation or by adjusting the angle of attack of the blades, but some lift of the angle of attack will be sacrifice at the same time. This paper proposes a new type of electric helicopter powertrain design. The advantage of new type helicopter design is setting the centre of gravity at the centre position of helicopter. The main shaft of the helicopter through the power transmission method of the electric motor built into the internal gear of the star gear, which improves the design of the center offset of the helicopter. That is improved the flight stability of the helicopter. At the same time, in terms of power transmission, the motor power consumed by the primary gear power of the star gear, while the traditional helicopter power transmission method has three or four gear power losses. The new concept of electric motor with star gear structure proposed in this paper can effectively reduce the transmission power loss of the gear. In addition, the distributed power control system proposed in this paper also reduces the possibility of helicopter crash due to motor failure.
Design of permanent magnet synchronous generator and anti-electromagnetic interference research
Authors: Liu Z S , Fang Z W , Li X X
Published: October 2022

Compared with the electric excitation synchronous generator, permanent magnet synchronous generator (PMSG) use permanent magnet excitation to replace electric field winding, which can simplify the motor structure and also reduce the motor weight and loss, improve the efficiency and the reliability of the motor. And it also eliminates the excitation loss. Permanent magnet synchronous generator (PMSG) has many advantages such as wide load range, strong overload capacity and obvious energy saving effect. Based on Motor design software, Motor-Cad, a permanent magnet synchronous generator (PMSG) was optimum designed in this paper it can be used as an independent backup power source for daily life, business, engineering construction site, emergency rescue and emergency treatment, and the establishment of its structure, performance parameter and mathematical model were studied. At the same time, how to improve the capacity of permanent magnet generator against electromagnetic radiation interference is also a problem considered. Therefore, a current switching device is designed in the control system to prevent electromagnetic pulse damage to the permanent magnet generator. The performance simulation verifies that the permanent magnet synchronous generator designed in this paper meets the design requirements completely.
Systematic innovation combined with bionic technology applied to innovative research on UAV
Authors: Fang J , Shiau Y R , Hung W C
Published: October 2022

This study aims to improve the two major problems faced by UAVs, short battery life and difficulty detecting hovering, respectively. For the problems mentioned above, this study derives the application of bionic technology and the integration of green energy innovation through systematic innovation theory, designing the operation of UAVs using this research method. The scope includes research on bionic technology, systematic innovation, innovation of unmanned aerial vehicles, and conduct fluid analysis for the output results, watching to confirm the hovering state, and analyzing the battery life to ensure the improvement of power supply, the output, and verification of this research can significantly improve the future development and application of UAVs.
The interface design of storage and examination system for BWR spent nuclear fuel dry storage demonstration project in Taiwan
Authors: Chen C H , Lin Y J , Chen C H , Yang C W
Published: October 2022

Due to the lack of Boiling Water Reactor (BWR) fuel examination data after dry storage, Taiwan Power Company and Institute of Nuclear Energy Research jointly launched the “Taiwan Nuclear Fuel Storage Demonstration Project” to collect fuel characteristics data under simulated dry storage. To meet the project requirements, BWR fuel rods in different fuel designs will be selected and then store in simulated storage containers in different environments for 10 years. The interface considerations and design results of the auxiliary equipment for spent nuclear fuel storage, transfer, and non-destructive testing in the simulation stage of spent fuel dry storage were summarized. In addition, the possibility of operating at high heating power and avoiding deformation of the components due to thermal extension of the storage containers after heating was included in the design consideration. A simplification concept was introduced, with frequent NDT (Non-destructive Testing) inspections that will be performed through the spent fuel transfer process. The test results showed that the interface design can meet the requirements of long-term experiment, maintenance and radiation protection requirements, and is ready for further demonstration.
Quantification of the Loading Coaxiality for the Uniaxial Material Test System with a Cylindrical Specimen via Optimized Neural Network
Authors: Chen Junxian , Zhang Jianhai
Published: October 2022

Material testing systems are crucial for evaluating the mechanical characteristics of materials. The material testing system’s accuracy determines the mechanical property of the material. Loading coaxiality is a crucial factor determining the precision of uniaxial tensile testing machines. Because of solid boundary nonlinearity in calculating loading coaxiality of the uniaxial test system, current methods can only be used for qualitative evaluation rather than quantification. Using the finite element method and the deep learning technique, a mapping relationship has been established between the strain measurements on the rod specimen and the alignment deviations of the material uniaxial testing system to quantify the loading coaxiality of the material testing system. The regularized genetic algorithm was further used to optimize the deep learning model’s hyperparameters, including learning rate, batch size, and network structure. Results showed that the deep learning model developed in this study could be used to quantify the alignment deviation of the uniaxial system based on strain distribution on the specimen. Besides providing a source for error analysis for material testing research, quantitative computation of alignment deviation can also guide the design, manufacture, and assembly of material uniaxial test systems.
Hearing screening based on deep residual shrinkage network
Authors: Huang Liling , Gong Qin
Published: October 2022

Stimulus-frequency otoacoustic emissions (SFOAEs) could be a useful tool for assessing hearing capabilities. Training and testing data were collected from 1084 ears of 725 subjects. Based on SFOAEs, this study applied Deep Residual Shrinkage Network to screen hearing status. Results of a 10-fold cross-validation show that the model performed better than other recent literature in the range of 0.5 to 8 kHz, occupied a larger area under the receiver operating characteristic curve (0.970-0.991) and had a higher accuracy (0.932-0.959). The developed classified model outperformed the previous model by accuracy improvements of 1.28% to 4.43% at 0.5, 2, 4 and 8 kHz.
Investigation on the hemispherical array structure for VLC transceiver
Authors: Liu Jiangnan , Peng Guojin , Su Jiapeng
Published: October 2022

To achieve high quality, strong adaptability, and stability of visible light communication system, this paper plans to study the hemispherical array structure to realize the alignment of the light path. The structured surface covers multiple LED and PD detection arrays according to the longitude and weft direction, realizing the bidirectional sending and receiving model. It is demonstrated that the effective light intensity ratio of the hemispherical array is higher than that of the planar array, and the interference between channels of the hemispherical array is less than that of the planar array under the same conditions. In addition, the influence mechanism of optical mechanism parameters (transceiver hemisphere array radius, LED tilt angle, and PD tilt angle) on beam scattering is established, and the influence of relative position changes between LED array and PD array on communication performance is clarified.
Exploration Strategy Improved DDPG for Lane Keeping Tasks in Autonomous Driving
Authors: Hua Gaoyang , Huang Zhiqiu , Wang Jinyong , Xie Jian , Shen Guohua
Published: October 2022

We propose an Exploration Strategy Improved Deep Deterministic Policy Gradient algorithm called ESI-DDPG for lane keeping tasks in autonomous driving. The actor network in DDPG outputs a policy which is deterministic, so it is necessary to add noise to actions so that the autonomous vehicle can fully explore the environment and learn the optimal policy. However, the initial weight of exploration noise is large, which makes the autonomous vehicle carry out a lot of invalid exploration in the early training stage. Therefore, we combine the Stanley method to make a weighted correction to the exploration noise, so that the exploration of the vehicle tends to be in the right direction and the training efficiency can be improved. In addition, due to the good sample data obtained in the training process, the driving policy finally learned is better. We choose TORCS as the experiment platform and the results show that, compared with DDPG, TD3 and SAC, our proposed algorithm can learn the driving policy faster and the final policy has smaller trajectory error while driving.
Multi-Grained Ranking Network for Event Extraction
Authors: Duan Rongcheng , Guo Peixin , Zhang Desheng
Published: October 2022

Event Extraction is a complicated task in Information Extraction including three subtasks: Entity Mention Detection, Event Detection, and Argument Role Prediction. Previous work for Event Extraction is usually done in the form of pipelined approach. Recently, end-to-end models for Event Extraction are getting more attention, but two problems still exist. First, different subtasks focus on different granularities of context information, but in the existing methods, all three subtasks share a unified representation, thus the information interested by a specific task may be underestimated or even ignored. Second, the interrelationship among events and entities has a strong influence in figuring out the meaning of a specific trigger or entity, but the existing methods are suffering in issues like time-dependency that a decision made later can only affect the rest of the sentence but has no way to update the previous one. Such limitations lead to insufficient use of the correlation between event elements in the sentence. In this paper, we propose a Multi-Grained Ranking Network for Event Extraction, which performs the three subtasks simultaneously in a single model. To handle the first problem, we design a dynamic Span Generator to construct multi-grained span representations from three granularities: sentence, neighbors, and content. Task-specific BERT-Rescale Gate units are applied in the Generator to capture the features of interest for each subtask respectively. As for the second challenge, we implement two attention mechanisms to explore the association of event-event and event-entity. The Events-Aware Attention is assigned to capture the association between events. While the Arguments-Aware Co-Attention is designed to model the relationship among entities in a specific event. The experiments on ACE-2005 prove that the proposed method outperforms the state-of-the-art methods in all subtasks of end-to-end Event Extraction.
Study of efficiency and gain uniformity at different gas flow rates of a quad-GEM detector
Authors: Bhattacharyya Rupamoy , Adak Rama Prasad , Sahu Sanjib Kumar , Sahu Pradip Kumar
Published: October 2022

A quad-GEM is particularly useful for its low ion back flow, excellent rate capability, good position resolution, high gain at relatively low operating voltage in the next generation high energy physics experiments. In this work, the efficiency and uniformity of gain of a prototype quad-GEM detector are studied. A simple method is used to estimate the efficiency with the help of an oscilloscope as a triggering and storage device. An efficiency of ≈ 95% is obtained at a voltage of ΔVGEM ≥ 340 V using cosmic muons as a source. A systematic study of the uniformity of gain over the active area of the detector is done with a Fe55 X-ray source.
The uniformity of gain has a spread of 11.1% over the active area of the quad-GEM detector for ΔVGEM = 360 V.
The effect of gas flow rate and direction of gas flow in determining the gain are investigated for the first time for a quad-GEM detector.
It is observed that different flow rates does not affect the gain uniformity significantly. However, the overall gain of the detector initially increases with the gas flow rate and starts to saturate at a higher flow rate.
Warmer winters are reducing potential ice roads and port accessibility in the Pan-Arctic
Authors: Dong Yuanbiao , Xiao Pengfeng , Zhang Xueliang , Wu Youlv , Wang Huadong , Luan Wenbo
Published: October 2022

Transportation in the Pan-Arctic winter is highly dependent on ice roads, which are affected by surface air temperatures and snow cover. In the context of polar increased warming, there is an urgent need to quantify the uncertainties of ice roads and their contribution to terrestrial transport. We evaluated the spatiotemporal characteristics of potential ice road changes by calculating four indicators: potential ice road area (PIRA), potential ice road days (PIRDs), potential ice road onset date (PIROD), and potential ice road end date (PIRED) from October to May, 1979–2017. Taking port accessibility as an example, we constructed a port accessibility model to quantify the contribution of potential ice roads to terrestrial transport. All four indicators showed significant (p < 0.05) reductions in potential ice roads. PIRA experienced the largest share of losses in May (∼25%) and the sharpest reductions in April (2.77 × 104 km2 yr−1). PIRDs were shortened by an average of 0.41 d yr−1, and delayed PIROD (0.28 d yr−1 on average) was more severe than advanced PIRED (0.21 d yr−1 on average). A stability analysis showed that potential ice roads were changing from suitable to unsuitable during November to May. Between December and April, potential ice roads can increase port accessibility by more than 24 h in Canadian Arctic and Siberia and by more than 9 h in Alaska. However, the contribution of potential ice roads has reduced over the past decades, especially in Nunavut. The results provide insights into changes in potential ice roads in the Pan-Arctic and suggest that remote land accessibility has decreased significantly with warmer winters.
Soliton crystals in optical Kerr microresonators in the presence of thermo-optic effects
Authors: Azah Bei Cho B , Ndifon Ngek I , Dikandé Alain M
Published: October 2022

The influence of thermo-optic effects on shape profiles of soliton crystals in optical Kerr microresonators is investigated. The study rests on a model that consists of the Lugiato–Lefever equation, coupled to the one-dimensional heat diffusion equation with a source term proportional to the average power of the optical field. Using appropriate variable changes the model equations are transformed into a set of coupled first-order nonlinear ordinary differential equations. These equations are solved numerically with emphasis on the influence of thermo-optic effects on the amplitude and instantaneous frequency of the optical field, as well as on the temperature profile in the microresonator cavity. It is found that thermo-optic effects do not prevent soliton crystals from forming in optical Kerr microresonators, however, a strong thermal detuning will decrease the soliton-crystal amplitude. The model predicts a temperature profile in the microresonator cavity which is insensitive to the specific spatio-temporal profile of the soliton crystal propagating in the microresonator, a feature peculiar to the model.
Fluctuation-driven initialization for spiking neural network training
Authors: Rossbroich Julian , Gygax Julia , Zenke Friedemann
Published: October 2022

Spiking neural networks (SNNs) underlie low-power, fault-tolerant information processing in the brain and could constitute a power-efficient alternative to conventional deep neural networks when implemented on suitable neuromorphic hardware accelerators. However, instantiating SNNs that solve complex computational tasks in-silico remains a significant challenge. Surrogate gradient (SG) techniques have emerged as a standard solution for training SNNs end-to-end. Still, their success depends on synaptic weight initialization, similar to conventional artificial neural networks (ANNs). Yet, unlike in the case of ANNs, it remains elusive what constitutes a good initial state for an SNN. Here, we develop a general initialization strategy for SNNs inspired by the fluctuation-driven regime commonly observed in the brain. Specifically, we derive practical solutions for data-dependent weight initialization that ensure fluctuation-driven firing in the widely used leaky integrate-and-fire neurons. We empirically show that SNNs initialized following our strategy exhibit superior learning performance when trained with SGs. These findings generalize across several datasets and SNN architectures, including fully connected, deep convolutional, recurrent, and more biologically plausible SNNs obeying Dale’s law. Thus fluctuation-driven initialization provides a practical, versatile, and easy-to-implement strategy for improving SNN training performance on diverse tasks in neuromorphic engineering and computational neuroscience.
Regular Functions on the 𝐾-nilpotent cone
Authors: Mason-Brown Lucas
Published: October 2022

Let

G
G

be a complex reductive algebraic group with Lie algebra

g

\mathfrak {g}

and let

G

R

G_{\mathbb {R}}

be a real form of

G
G

with maximal compact subgroup

K

R

K_{\mathbb {R}}

. Associated to

G

R

G_{\mathbb {R}}

is a

K
×

C

×

K \times \mathbb {C}^{\times }

-invariant subvariety

N

θ

\mathcal {N}_{\theta }

of the (usual) nilpotent cone

N

⊂

g

∗

\mathcal {N} \subset \mathfrak {g}^*

. In this article, we will derive a formula for the ring of regular functions

C

[

N

θ

]

\mathbb {C}[\mathcal {N}_{\theta }]

as a representation of

K
×

C

×

K \times \mathbb {C}^{\times }

.

Some motivation comes from Hodge theory. In [Hodge theory and unitary representations of reductive Lie groups, Frontiers of Mathematical Sciences, Int. Press, Somerville, MA, 2011, pp. 397–420], Schmid and Vilonen use ideas from Saito’s theory of mixed Hodge modules to define canonical good filtrations on many Harish-Chandra modules (including all standard and irreducible Harish-Chandra modules). Using these filtrations, they formulate a conjectural description of the unitary dual. If

G

R

G_{\mathbb {R}}

is split, and

X
X

is the spherical principal series representation of infinitesimal character

0
0

, then conjecturally

g
r
(
X
)
≃

C

[

N

θ

]

gr(X) \simeq \mathbb {C}[\mathcal {N}_{\theta }]

as representations of

K
×

C

×

K \times \mathbb {C}^{\times }

. So a formula for

C

[

N

θ

]

\mathbb {C}[\mathcal {N}_{\theta }]

is an essential ingredient for computing Hodge filtrations.
Association Between Social Determinants of Health and Glycemic Control Among African American People with Type 2 diabetes: The Jackson Heart Study
Authors: Hu Jie , Kline David M , Tan Alai , Zhao Songzhu , Brock Guy , Mion Lorraine C , Efird Jimmy T , Wang Danxin , Sims Mario , Wu Bei , Mongraw-Chaffin Morgana , Joseph Joshua J
Published: October 2022

Background

Social determinants of health have a significant impact on health outcomes. However, the complexity and interaction of multiple factors influencing glycemic control remain understudied.

Purpose

This study examined associations of socioeconomic position (income, education, and occupation), environmental (physical activity facilities, neighborhood social cohesion, neighborhood problem, and violence), behavioral (physical activity, nutrition, and smoking), and psychological factors (depressive symptoms, stress, and discrimination) with glycemic control (hemoglobin A1c [A1c]) using the World Health Organization Social Determinants of Health framework in African American adults with type 2 diabetes.

Methods

A secondary data analysis was conducted using a longitudinal cohort of 1,240 African American adults with type 2 diabetes who participated in the community-based Jackson Heart Study. Socioeconomic position, environmental, behavioral, and psychological factors were measured using validated instruments in the Jackson Heart Study. Longitudinal structural equation modeling was used with glycemic control (A1c) collected over time (Exams 1–3) as the study outcome.

Results

Our study presents the complex interplay of socioeconomic determinants of health and glycemic control over time. Higher socioeconomic position (higher income, higher level of education, and professional occupation) was directly associated with improvement in glycemic control over time. An association of socioeconomic position on glycemic control mediated through health behavior factors was also observed.

Conclusions

In this analysis, socioeconomic position components were determinants of glycemic control in African American adults with type 2 diabetes. Future studies aimed at reducing health disparities and achieving equality of outcomes in this population will benefit from embedding socioeconomic position components into their design.
A Quantitative and Qualitative Assessment of Frozen Section Diagnosis Accuracy and Deferral Rate Across Organ Systems
Authors: Mohamed Anas , Hassan Muhammad Masood , Zhong Wen , Kousar Aisha , Takeda Kotaro , Donthi Deepak , Rizvi Areeba , Majeed Marwan , Younes Ahmed I , Ali Ahlam , Sutton Ann , Murray Gina , Thayyil Abdullah , Fallon John , Geisinger Kim
Published: October 2022

Objectives

Monitoring of frozen section diagnostic performance provides an important quality improvement measure.

Methods

Surgical specimens involving a frozen section diagnosis over a 3-year period were retrospectively reviewed. Glass slides were reviewed on cases with discordance. Discordance and deferral rates were calculated.

Results

Of 3,675 frozen section diagnoses included, 96 (2.7%) were discordant with the final diagnosis. Additionally, 114 frozen section diagnoses (3.1%) were deferred. The organ-specific discordance rates were lowest in breast and genitourinary specimens and highest for pancreas, lymph node, and gynecologic specimens. Deferral rates were highest in musculoskeletal, breast, and hepatobiliary cases and lowest in thyroid, parathyroid, and neuropathology cases. Discordance was explained by block-sampling error (45%), specimen-sampling error (27%), or interpretation error (27%). Discordant frozen section diagnoses from gynecologic specimens were responsible for 81% of specimen-sampling errors; frozen section diagnoses of lymph nodes, head and neck, and pancreas were responsible for 54% of interpretation errors; 51% of block-sampling errors involved lymph node evaluation for metastatic carcinoma.

Conclusions

Careful gross evaluation and microscopic examination of multiple levels should minimize specimen-sampling error and block-sampling error, respectively. Periodic review of accuracy and deferral rates may help reduce errors and improve the overall performance of this essential procedure.
Changes in Coagulation Testing During a National Shortage of Blue-Top Tubes
Authors: Schuett Hannah G , Volod Oksana , Berg Anders H , Rhee Kyu , Torbati Sam S , Riggs Richard V , Frishberg David P
Published: October 2022

Objectives

Manufacturer recalls and altered supply chains during the coronavirus disease 2019 (COVID-19) pandemic caused a nationwide shortage of blue-top tubes (BTTs). Most non–point-of-care coagulation tests use these tubes, leaving laboratories and health care facilities in short supply. The Department of Pathology and Laboratory Medicine at Cedars-Sinai Medical Center implemented interventions to conserve supply without sacrificing patient safety.

Methods

In a retrospective quality improvement analysis, we examined coagulation testing and BTT utilization over the 3-month interval during which our interventions were applied. Our study assessed the interventions’ effectiveness by evaluating changes in BTT utilization, coagulation testing volume, and patient impact.

Results

Average daily use (ADU) of BTT before and after the intervention were 476 and 403, respectively—a 15.2% reduction. Notably, the Emergency Department had a reduction in ADU of 43.3%. Average daily volumes of coagulation assays performed decreased from 949 to 783—a 17.5% reduction. No adverse events from the Pharmacy Department were identified during the study period.

Conclusions

Interventions resulting in significant reductions were in divisions with effective management and supervision. Success in navigating the BTT shortage stemmed from timely announcements, action, and effective communication. Our recommendations established more effective coagulation assay utilization, decreased overall BTT use, and prevented patients with coagulopathic disorders from experiencing adverse consequences.
ncRNAInter: a novel strategy based on graph neural network to discover interactions between lncRNA and miRNA
Authors: Zhang Hanyu , Wang Yunxia , Pan Ziqi , Sun Xiuna , Mou Minjie , Zhang Bing , Li Zhaorong , Li Honglin , Zhu Feng
Published: October 2022

In recent years, many studies have illustrated the significant role that non-coding RNA (ncRNA) plays in biological activities, in which lncRNA, miRNA and especially their interactions have been proved to affect many biological processes. Some in silico methods have been proposed and applied to identify novel lncRNA–miRNA interactions (LMIs), but there are still imperfections in their RNA representation and information extraction approaches, which imply there is still room for further improving their performances. Meanwhile, only a few of them are accessible at present, which limits their practical applications. The construction of a new tool for LMI prediction is thus imperative for the better understanding of their relevant biological mechanisms. This study proposed a novel method, ncRNAInter, for LMI prediction. A comprehensive strategy for RNA representation and an optimized deep learning algorithm of graph neural network were utilized in this study. ncRNAInter was robust and showed better performance of 26.7% higher Matthews correlation coefficient than existing reputable methods for human LMI prediction. In addition, ncRNAInter proved its universal applicability in dealing with LMIs from various species and successfully identified novel LMIs associated with various diseases, which further verified its effectiveness and usability. All source code and datasets are freely available at https://github.com/idrblab/ncRNAInter.
Caffeine for intestinal transit after laparoscopic colectomy: randomized clinical trial (CaCo trial)
Authors: Abbassi Fariba , Müller Sascha A , Steffen Thomas , Schmied Bruno M , Warschkow René , Beutner Ulrich , Tarantino Ignazio
Published: October 2022

Background

Coffee has been suggested to help postoperative gastrointestinal motility but the mechanism is not known. This trial assessed whether caffeine shortened time to bowel activity after laparoscopic colectomy.

Methods

This was a single-centre, randomized, double-blinded, placebo-controlled superiority trial (October 2015 to August 2020). Patients aged at least 18 years undergoing elective laparoscopic colectomy were assigned randomly to receive 100 mg or 200 mg caffeine, or a placebo (250 mg corn starch) three times a day orally. The primary endpoint was the time to first bowel movement. Secondary endpoints included colonic transit time, time to tolerance of solid food, duration of hospital stay, and perioperative morbidity.

Results

Sixty patients were assigned randomly to either the 200-mg caffeine group (20 patients), the 100-mg caffeine group (20) or the placebo group (20). In the intention-to-treat analysis, the mean(s.d.) time to first bowel movement was 67.9(19.2) h in the 200-mg caffeine group, 68.2(32.2) h in the 100-mg caffeine group, and 67.3(22.7) h in the placebo group (P = 0.887). The per-protocol analysis and measurement of colonic transit time confirmed no measurable difference with caffeine.

Conclusion

Caffeine was not associated with reduced time to first bowel movement.

Registration number

NCT02510911 (http://www.clinicaltrials.gov).
Impact of classical and basal-like molecular subtypes on overall survival in resected pancreatic cancer in the SPACIOUS-2 multicentre study
Authors: Suurmeijer J Annelie , Soer Eline C , Dings Mark P G , Kim Yongsoo , Strijker Marin , Bonsing Bert A , Brosens Lodewijk A A , Busch Olivier R , Groen Jesse V , Halfwerk Johannes B , Slooff Robbert A E , van Laarhoven Hanneke W M , Molenaar I Quintus , Offerhaus G Johan A , Morreau Hans , van de Vijver Marc J , Fariña Sarasqueta Arantza , Verheij Joanne , Besselink Marc G , Bijlsma Maarten F , Dijk Frederike ,   for the Dutch Pancreatic Cancer Group, de Guerre Livia
Published: October 2022

Background

The recently identified classical and basal-like molecular subtypes of pancreatic cancer impact on overall survival (OS). However, the added value of routine subtyping in both clinical practice and randomized trials is still unclear, as most studies do not consider clinicopathological parameters. This study examined the clinical prognostic value of molecular subtyping in patients with resected pancreatic cancer.

Methods

Subtypes were determined on fresh-frozen resected pancreatic cancer samples from three Dutch centres using the Purity Independent Subtyping of Tumours classification. Patient, treatment, and histopathological variables were compared between subtypes. The prognostic value of subtyping in (simulated) pre- and postoperative settings was assessed using Kaplan–Meier and Cox regression analyses.

Results

Of 199 patients with resected pancreatic cancer, 164 (82.4 per cent) were classified as the classical and 35 (17.6 per cent) as the basal-like subtype. Patients with a basal-like subtype had worse OS (11 versus 16 months (HR 1.49, 95 per cent c.i. 1.03 to 2.15; P = 0.035)) than patients with a classical subtype. In multivariable Cox regression analysis, including only clinical variables, the basal-like subtype was a statistically significant predictor for poor OS (HR 1.61, 95 per cent c.i. 1.11 to 2.34; P = 0.013). When histopathological variables were added to this model, the prognostic value of subtyping decreased (HR 1.49, 95 per cent c.i. 1.01 to 2.19; P = 0.045).

Conclusion

The basal-like subtype was associated with worse OS in patients with resected pancreatic cancer. Adding molecular classification to inform on tumor biology may be used in patient stratification.
Cost-effectiveness of ursodeoxycholic acid in preventing new-onset symptomatic gallstone disease after Roux-en-Y gastric bypass surgery
Authors: Haal Sylke , Guman Maimoena S S , de Brauw L Maurits , Schouten Ruben , van Veen Ruben N , Fockens Paul , Gerdes Victor E A , Voermans Rogier P , Dijkgraaf Marcel G W
Published: October 2022

Background

The aim was to evaluate the cost-effectiveness and cost–utility of ursodeoxycholic acid (UDCA) prophylaxis for the prevention of symptomatic gallstone disease after Roux-en-Y gastric bypass (RYGB) in patients without gallstones before surgery.

Methods

Data from a multicentre, double-blind, randomized placebo-controlled superiority trial were used. Patients scheduled for laparoscopic RYGB or sleeve gastrectomy were randomized to receive 900 mg UDCA or placebo for 6 months. Indicated by the clinical report, prophylactic prescription of UDCA was evaluated economically against placebo from a healthcare and societal perspective for the subgroup of patients without gallstones before surgery who underwent RYGB. Volumes and costs of in-hospital care, out-of-hospital care, out-of-pocket expenses, and productivity loss were assessed. Main outcomes were the costs per patient free from symptomatic gallstone disease and the costs per quality-adjusted life-year (QALY).

Results

Patients receiving UDCA prophylaxis were more likely to remain free from symptomatic gallstone disease (relative risk 1.06, 95 per cent c.i. 1.02 to 1.11; P = 0.002) compared with patients in the placebo group. The gain in QALYs, corrected for a baseline difference in health utility, was 0.047 (95 per cent bias-corrected and accelerated (Bca) c.i. 0.007 to 0.088) higher (P = 0.022). Differences in costs were –€356 (95 per cent Bca c.i. €–1573 to 761) from a healthcare perspective and –€1392 (–3807 to 917) from a societal perspective including out-of-pocket expenses and productivity loss, both statistically non-significant, in favour of UDCA prophylaxis. The probability of UDCA prophylaxis being cost-effective was at least 0.872.

Conclusion

UDCA prophylaxis after RYGB in patients without gallstones before surgery was cost-effective.
Unexpected deaths after endocrine surgery: learning from rare events using a national audit of surgical mortality
Authors: Chui Juanita N , Papachristos Alexander J , Mechera Robert , Sidhu Stan B , Sywak Mark S , Lee James C , Gundara Justin , Lai Christine , Glover Anthony R
Published: October 2022

Background

The mortality rate is low in endocrine surgery, making it a difficult outcome to use for quality improvement in individual units. Lessons from population data sets are of value in improving outcomes. Data from the Australian and New Zealand Audit of Surgical Mortality (ANZASM) were used here to understand and elucidate potential systems issues that may contribute to preventable deaths.

Methods

ANZASM data relating to 30-day mortality after thyroidectomy, parathyroidectomy, and adrenalectomy from 2009 to 2020 were reviewed. Mortality rates were calculated using billing data. Thematic analysis of independent assessor reports was conducted to produce a coding framework.

Results

A total of 67 deaths were reported, with an estimated mortality rate of 0.03–0.07 per cent (38 for thyroidectomy (0.03–0.06 per cent), 16 for parathyroidectomy (0.03–0.06 per cent), 13 for adrenalectomy (0.15–0.33 per cent)). Twenty-seven deaths (40 per cent) were precipitated by clinically significant adverse events, and 18 (27 per cent) were judged to be preventable by independent ANZASM assessors. Recurrent themes included inadequate preoperative assessment, lack of anticipation of intraoperative pitfalls, and failure to recognize and effectively address postoperative complications. Several novel themes were reiterated, such as occult ischaemic heart disease associated with death after parathyroid surgery, unexpected intraoperative difficulties from adrenal metastasis, and complications due to anticoagulation therapy after thyroid surgery.

Conclusion

This study represents a large-scale national report of deaths after endocrine surgery and provides insights into these rare events. Although the overall mortality rate is low, 27 per cent of deaths involved systems issues that were preventable following independent peer review.
Population-based study of treatment and outcome of recurrent oesophageal or junctional cancer
Authors: Pape Marieke , Vissers Pauline A J , Bertwistle David , McDonald Laura , Beerepoot Laurens V , van Berge Henegouwen Mark I , Lagarde Sjoerd M , Mook Stella , Mohammad Nadia Haj , Jeene Paul M , van Laarhoven Hanneke W M , Verhoeven Rob H A
Published: October 2022

Background

Patients with cancer of the oesophagus or gastro-oesophageal junction have a high risk of recurrence after treatment with curative intent. The aim of this study was to analyse the site of recurrence, treatment, and survival in patients with recurrent disease.

Methods

Patients with non-metastatic oesophageal or junctional carcinoma treated with curative intent between January 2015 and December 2016 were selected from the Netherlands Cancer Registry. Data on recurrence were collected in the second half of 2019. Overall survival (OS) was assessed by Kaplan–Meier methods.

Results

In total, 862 of 1909 patients (45.2 per cent) for whom information on follow-up was available had disease recurrence, and 858 patients were included. Some 161 of 858 patients (18.8 per cent) had locoregional recurrence only, 415 (48.4 per cent) had distant recurrence only, and 282 (32.9 per cent) had combined locoregional and distant recurrence. In all, 518 of 858 patients (60.4 per cent) received best supportive care only and 315 (39.6 per cent) underwent tumour-directed therapy. Patients with locoregional recurrence alone more often received chemoradiotherapy than those with distant or combined locoregional and distant recurrence (19.3 per cent versus 0.7 and 2.8 per cent), and less often received systemic therapy (11.2 per cent versus 30.1 and 35.8 per cent). Median OS was 7.6, 4.2, and 3.3 months for patients with locoregional, distant, and combined locoregional and distant recurrence respectively (P < 0.001).

Conclusion

Disease recurred after curative treatment in 45.2 per cent of patients. Locoregional recurrence developed in only 18.8 per cent. The vast majority of patients presented with distant or combined locoregional and distant recurrence, and received best supportive care.
Chromosome-level genome of a leaf vegetableGlebionis coronariaprovides insights into the biosynthesis of monoterpenoids contributing to its special aroma
Authors: Wang Sen , Wang Anqi , Wang Hengchao , Jiang Fan , Xu Dong , Fan Wei
Published: October 2022

Glebionis coronaria is a popular vegetable with special aroma and a medical plant in East Asia and Mediterranean, but its biological studies and breeding have been hindered by the lack of reference genome. Here, we present a chromosome-level reference genome of G. coronaria, with assembled genome size of 6.8 Gb, which is the largest among all the published genomes of diploid Asteraceae species. The large genome size of G. coronaria is mainly caused by the recent widespread explosions of long-terminal-repeat retrotransposons. Analyses of macro-synteny and synonymous mutation rate distribution indicate that the G. coronaria genome experienced a whole-genome triplication at 40–45 million years ago, shared with all Asteraceae species. In subtribe Artemisiinae, Glebionis arose before the divergence of Chrysanthemum from Artemisia, and Glebionis species evolved much faster than Chrysanthemum and Artemisia species. In G. coronaria, the synthesis genes of monoterpenoids 8-oxocitronellyl enol and isopiperitenone were expanded, and the higher expressions of these expanded genes in leaves and stems may contribute to its special aroma. The G. coronaria genomic resources will promote the evolution studies of Asteraceae, the metabolism mechanism studies of bioactive compounds, and the breeding improvement of agronomic traits in G. coronaria.
First report of myocarditis in two patients with COVID-19 Omicron variant: case report
Authors: Fishman Boris , Goitein Orly , Berkovitch Anat , Rahav Galia , Matetzky Shlomi
Published: October 2022

Background

Severe acute respiratory syndrome coronavirus 2 infection is responsible for the coronavirus disease 2019 (COVID-19) pandemics. Omicron (B.1.1.529) variant is the cause for the surge of the COVID-19 pandemics of the end of 2021 and the beginning of 2022, although its subvariants are responsible for the following daily increase of COVID-19 cases in July 2022. Early reports of Omicron variant confirmed patients indicated less severe disease course compared with the disease caused by previously encountered variants with absence of data regarding cardiac involvement by Omicron.

Case summary

A 42-year-old male who tested positive for Omicron was admitted on January 2022 with chest pain and ST-segment elevation in the inferior leads. Coronary angiography revealed non-significant coronary artery disease. Cardiac magnetic resonance imaging demonstrated features consistent with myocarditis with involvement of 22% of the left ventricular mass by late gadolinium enhancement involving both the lateral and the septal walls. The second patient is a 60-year-old male presented following syncope and palpitations after he was confirmed with Omicron infection. Upon emergency department arrival he had ventricular tachycardia of 250 beats/minute and underwent urgent cardioversion. During his hospitalization, there was no recurrence of malignant arrhythmia, coronary angiography revealed non-obstructive disease. Cardiac magnetic resonance imaging demonstrated imaging features suggesting acute myocarditis with involvement of 19% of the left ventricular mass.

Discussion

This is the first report of myocarditis cases as a possible complication associated with Omicron variant. Despite preliminary reports of less severe disease clinicians should be vigilant for potential deleterious cardiac complications of Omicron.
The risk of cardiovascular diseases after miscarriage, stillbirth, and induced abortion: a systematic review and meta-analysis
Authors: Kyriacou Harry , Al-Mohammad Abdulrahman , Muehlschlegel Charlotte , Foster-Davies Lowri , Bruco Maria Eduarda Ferreira , Legard Chloe , Fisher Grace , Simmons-Jones Fiona , Oliver-Williams Clare
Published: October 2022

Aims

Miscarriage and stillbirth have been included in cardiovascular disease (CVD) risk guidelines, however heterogeneity in exposures and outcomes and the absence of reviews assessing induced abortion, prevented comprehensive assessment. We aimed to perform a systematic review and meta-analysis of the risk of cardiovascular diseases for women with prior pregnancy loss (miscarriage, stillbirth, and induced abortion).

Methods and results

Observational studies reporting risk of CVD, coronary heart disease (CHD), and stroke in women with pregnancy loss were selected after searching MEDLINE, Scopus, CINAHL, Web of Knowledge, and Cochrane Library (to January 2020). Data were extracted, and study quality were assessed using the Newcastle-Ottawa Scale. Pooled relative risk (RR) and 95% confidence intervals (CIs) were calculated using inverse variance weighted random-effects meta-analysis.

Twenty-two studies involving 4 337 683 women were identified. Seven studies were good quality, seven were fair and eight were poor. Recurrent miscarriage was associated with a higher CHD risk (RR = 1.37, 95% CI: 1.12–1.66). One or more stillbirths was associated with a higher CVD (RR = 1.41, 95% CI: 1.09–1.82), CHD (RR = 1.51, 95% CI: 1.04–1.29), and stroke risk (RR = 1.33, 95% CI: 1.03–1.71). Recurrent stillbirth was associated with a higher CHD risk (RR = 1.28, 95% CI: 1.18–1.39). One or more abortions was associated with a higher CVD (RR = 1.04, 95% CI: 1.02–1.07), as was recurrent abortion (RR = 1.09, 95% CI: 1.05–1.13).

Conclusion

Women with previous pregnancy loss are at a higher CVD, CHD, and stroke risk. Early identification and risk factor management is recommended. Further research is needed to understand CVD risk after abortion.
Optimization of anti-tachycardia pacing efficacy through scar-specific delivery and minimization of re-initiation: a virtual study on a cohort of infarcted porcine hearts
Authors: Qian Shuang , Connolly Adam , Mendonca-Costa Caroline , Campos Fernando , Rodero Cristobal , Whitaker John , Rinaldi Christopher A , Bishop Martin J
Published: October 2022

Aims

Anti-tachycardia pacing (ATP) is a reliable electrotherapy to painlessly terminate ventricular tachycardia (VT). However, ATP is often ineffective, particularly for fast VTs. The efficacy may be enhanced by optimized delivery closer to the re-entrant circuit driving the VT. This study aims to compare ATP efficacy for different delivery locations with respect to the re-entrant circuit, and further optimize ATP by minimizing failure through re-initiation.

Methods and results

Seventy-three sustained VTs were induced in a cohort of seven infarcted porcine ventricular computational models, largely dominated by a single re-entrant pathway. The efficacy of burst ATP delivered from three locations proximal to the re-entrant circuit (septum) and three distal locations (lateral/posterior left ventricle) was compared. Re-initiation episodes were used to develop an algorithm utilizing correlations between successive sensed electrogram morphologies to automatically truncate ATP pulse delivery. Anti-tachycardia pacing was more efficacious at terminating slow compared with fast VTs (65 vs. 46%, P = 0.000039). A separate analysis of slow VTs showed that the efficacy was significantly higher when delivered from distal compared with proximal locations (distal 72%, proximal 59%), being reversed for fast VTs (distal 41%, proximal 51%). Application of our early termination detection algorithm (ETDA) accurately detected VT termination in 79% of re-initiated cases, improving the overall efficacy for proximal delivery with delivery inside the critical isthmus (CI) itself being overall most effective.

Conclusion

Anti-tachycardia pacing delivery proximal to the re-entrant circuit is more effective at terminating fast VTs, but less so slow VTs, due to frequent re-initiation. Attenuating re-initiation, through ETDA, increases the efficacy of delivery within the CI for all VTs.
Prognostic value of right ventricular refractory period heterogeneity in Type-1 Brugada electrocardiographic pattern
Authors: Rossi Andrea , Giannoni Alberto , Nesti Martina , Notarstefano Pasquale , Castiglione Vincenzo , Solarino Gianluca , Teresi Lucio , Mirizzi Gianluca , Russo Vincenzo , Panchetti Luca , Startari Umberto , Ripoli Andrea , Gentile Francesco , Santoro Amato , Botto Nicoletta , Casolo Giancarlo , Sieira Juan , Pieroni Maurizio , Santangeli Pasquale , Emdin Michele , Piacenti Marcello
Published: October 2022

Aims

To investigate the prognostic significance of heterogeneity in the refractoriness of right ventricular (RV) outflow tract (RVOT) and RV apex at the electrophysiological study (EPS) in Brugada syndrome (BrS).

Methods and results

A cohort of BrS patients (primary prevention) from five Italian centres was retrospectively analysed. Patients with spontaneous or drug-induced Type-1 electrocardiogram (ECG) + symptoms were offered an EPS for prognostic stratification. The primary endpoint was a composite of sudden cardiac death (SCD), resuscitated cardiac arrest, or appropriate intervention by the implantable cardioverter-defibrillator (ICD). Three hundred and seventy-two patients with BrS were evaluated (44 ± 15 years, 69% males, 23% with ICD): 4 SCDs and 17 ICD interventions occurred at follow-up (median 48, interquartile range: 36–60 months). Family history of SCD, syncope, and a spontaneous Type-1 ECG pattern were univariate predictors of the primary endpoint in the whole population. In patients undergoing EPS (n = 198, 53%, 44 ± 12 years, 71% males, 39% with ICD), 3 SCD and 15 ICD interventions occurred at follow-up. In this subset, the primary endpoint was not only predicted by ventricular tachycardia/fibrillation inducibility but also by a difference in the refractory period between RVOT and RV apex (ΔRPRVOT-apex) >60 ms. ΔRPRVOT-apex > 60 ms remained an independent predictor of SCD/ICD shock at bivariate analysis, even when adjusted for the other univariate predictors, showing the highest predictive power at C-statistic analysis (0.75, 95% confidence interval 0.63–0.86).

Conclusions

Heterogeneity of RV refractory periods is a strong, independent predictor of life-threatening arrhythmias in BrS patients, beyond VT/VF inducibility at EPS and common clinical predictors.