bluuebunny/crossref_metadata_2025 huggingface dataset:
A small piezoelectric stack motor designed for vacuum and micro-dust environment
Authors: Wan Hao , Peng Hanmin , Tang Xiongfeng , Chen Wangyi
Published: November 2022

With the development of moon exploration, higher requirements have been proposed for the adaptability of small motors under vacuum and micro-dust conditions. In this paper, a rotational motor based on piezoelectric stacks is proposed, which can be driven by a single-phase direct current with a simple drive circuit. The motor dimensions are 24 mm × 24 mm × 24 mm (length × width × height), and the mass is 11.4 g. In air environment, the maximum output rotational speed of the motor is 1372 rpm, and the maximum stall torque is 3.2 mN m at 40 V
DC and 5.93 kHz. An open-loop control system is established to drive the stepping motion of the motor, and the minimum stepping angle is measured as 0.122 mrad. An environmental experiment of the motor is conducted in a lunar simulator module, which can simulate a high vacuum (6.7 × 10−5 Pa) and micro-dust (average 75 μm) environment of the lunar surface. The result shows that the motor can work steadily in the vacuum and micro-dust environment with an average speed of 1723 rpm, which demonstrates its potential applications in the space environment.
Frequency dependent sensitivity of hydrogel iontronic sensor
Authors: Liu Haiyang , Guo Haoyu , Yang Meng , Liu Jianxing , Lu Tongqing
Published: November 2022

The hydrogel iontronic sensor (HIS) has attracted much attention in recent years due to its high sensitivity. The physical model to analyze the effects of various parameters on the sensitivity of the HIS is still lacking. In this work, we conduct experiments to study the effects of voltage frequency, sensor size, and ion concentration on the sensitivity of the HIS. The experimental results show that the sensitivity is highly dependent on frequency in the range of 20–1 MHz. We establish a theoretical model consisting of Possion–Nerust–Planck equations to describe the ion migration and incompressible Neo-Hookean constitutive equation to describe the hydrogel deformation. The theoretical results divide the sensitivity into three regions of frequency: the region dominated by fully formed electric double layers at the electrode-hydrogel interfaces, the region dominated by ionic relaxation of the hydrogel, and the region dominated by the dielectric property of hydrogel. The model agrees well with the experiments on the frequency dependence of sensitivity as well as the effect of size and ion concentration. This work may provide a guidance for the design of highly sensitive HIS.
Initial correlations in open quantum systems: constructing linear dynamical maps and master equations
Authors: Colla Alessandra , Neubrand Niklas , Breuer Heinz-Peter
Published: November 2022

We investigate the dynamics of open quantum systems which are initially correlated with their environment. The strategy of our approach is to analyze how given, fixed initial correlations modify the evolution of the open system with respect to the corresponding uncorrelated dynamical behavior with the same fixed initial environmental state, described by a completely positive dynamical map. We show that, for any predetermined initial correlations, one can introduce a linear dynamical map on the space of operators of the open system which acts like the proper dynamical map on the set of physical states and represents its unique linear extension. Furthermore, we demonstrate that this construction leads to a linear, time-local quantum master equation with generalized Lindblad structure involving time-dependent, possibly negative transition rates. Thus, the general non-Markovian dynamics of an open quantum system can be described by means of a time-local master equation even in the case of arbitrary, fixed initial system–environment correlations. We present some illustrative examples and explain the relation of our approach to several other approaches proposed in the literature.
Inferring oscillator’s phase and amplitude response from a scalar signal exploiting test stimulation
Authors: Cestnik Rok , Mau Erik T K , Rosenblum Michael
Published: November 2022

The phase sensitivity curve or phase response curve (PRC) quantifies the oscillator’s reaction to stimulation at a specific phase and is a primary characteristic of a self-sustained oscillatory unit. Knowledge of this curve yields a phase dynamics description of the oscillator for arbitrary weak forcing. Similar, though much less studied characteristic, is the amplitude response that can be defined either using an ad hoc approach to amplitude estimation or via the isostable variables. Here, we discuss the problem of the phase and amplitude response inference from observations using test stimulation. Although PRC determination for noise-free neuronal-like oscillators perturbed by narrow pulses is a well-known task, the general case remains a challenging problem. Even more challenging is the inference of the amplitude response. This characteristic is crucial, e.g. for controlling the amplitude of the collective mode in a network of interacting units—a task relevant to neuroscience. Here, we compare the performance of different techniques suitable for inferring the phase and amplitude response, particularly with application to macroscopic oscillators. We suggest improvements to these techniques, e.g. demonstrating how to obtain the PRC in case of stimuli of arbitrary shape. Our main result is a novel technique denoted by IPID-1, based on the direct reconstruction of the Winfree equation and the analogous first-order equation for isostable dynamics. The technique works for signals with or without well-pronounced marker events and pulses of arbitrary shape; in particular, we consider charge-balanced pulses typical in neuroscience applications. Moreover, this technique is superior for noisy and high-dimensional systems. Additionally, we describe an error measure that can be computed solely from data and complements any inference technique.
Effect of the electrical double layer on the electrical conductivity of suspensions
Authors: Sushko M Ya , Balika S D
Published: November 2022

We study the role of the electrical double layer (EDL) in the formation of the quasistatic electrical conductivity of suspensions of nanosized particles. A suspension is viewed as a system of hard-core–penetrable-shell particles. The shells are electrically inhomogeneous, with a radially symmetrical conductivity profile. It is assumed that the real microstructure of the suspension can be reflected in terms of this profile and also the rule of dominance for overlapping regions that the local conductivity in the system is determined by the nearest particle. Using our earlier rigorous results for systems with this morphology, we derive general integral relations for the desired conductivity which incorporate the effect of the EDL and make it possible to look into the contributions from its different parts and parameters. Specific features, internal consistency, and flexibility of the model are demonstrated by further elaborating it to describe experimental data for latex suspensions in aqueous electrolyte solutions with high ionic strength.
Structural analysis of the ro-vibrational states of screened hydrogen molecular ion

H2+

in the regime of Borromean binding
Authors: Mondal S , Sadhukhan A , Mukhopadhyay T K , Pawlak M , Saha J K
Published: November 2022

A detailed analysis on the structural properties of first three ro-vibrational (J = 0, ν = 0, 1, 2; J and ν being the rotational and vibrational quantum numbers, respectively) states of

H

2

+

ion bound via screened Coulomb interaction has been reported. Generalized Hylleraas type basis set has been considered to construct the trial wave function under the Ritz variational framework. In order to incorporate the localized relative motion of the protons (or nuclei), we have used high powers of the interprotonic (or internuclear) distance in the basis set. The Borromean binding regime or the Borromean window (BW) has been identified for the said three states of

H

2

+

ion. The energy components contributing to the total energy are estimated as a parametric function of the screening parameter. Different geometrical entities e.g. radial moments

〈

r

i

p

〉

(p = − 1, 1 and 2), angular moments

〈
cos

θ

i

〉

[(i) = (1) or (12)], expectation value of the delta function

δ
(

r

⃗

1

)

as well as the one-particle density are determined to get a clear view of the structural behaviour of

H

2

+

ion in its ground state as well as in the excited states, specially within the BW.
Magnetic potential based formulation for linear and non-linear 3D RF sheath simulation
Authors: Shiraiwa S. , Bertelli N. , Tierens W. , Bilato R. , Hillairet J. , Myra J. , Kohno H. , Poulos M. , Ono M.
Published: November 2022

This paper reports a new numerical scheme to simulate the radio-frequency (RF) induced RF sheath, which is suitable for a large 3D simulation. In the RF sheath boundary model, the tangential component of the electric field (

E

t

) is given by the gradient of a scalar electric field potential. We introduce two additional scalar potentials for the tangential components of the magnetic field, which effectively impose the normal electric displacement (D

n
) on the plasma sheath boundary condition via in-homogeneous Neumann boundary condition and constrain the tangential electric field on the surface as curl-free (

∇
×

E

t

=
0

). In our approach, the non-linear sheath impedance is formulated as a natural extension of the large thickness (or asymptotic) sheath limit (

D

n

=
0

), allowing for handling both asymptotic and non-linear regimes seamlessly. The new scheme is implemented using the Petra-M finite element method analysis framework and is verified with simulations in the literature. The significance of non-linearity is discussed in various plasma conditions. An application of this scheme to asymptotic RF sheath simulation on the WEST ICRF antenna side limiters is also discussed.
On the interaction between the island divertor heat fluxes, the scrape-off layer radial electric field and the edge turbulence in Wendelstein 7-X plasmas
Authors: Maragkoudakis E. , Carralero D. , Estrada T. , Windisch T. , Gao Y. , Killer C. , Jakubowski M. , Puig Sitjes A. , Pisano F. , Sándor H. , Vecsei M. , Zoletnik S. , Cappa A.
Published: November 2022

The formation of the radial electric field,

E

r

in the scrape-off layer (SOL) has been experimentally studied for attached divertor conditions in stellarator W7-X. The main objective of this study is to test the validity in a complex three-dimensional (3D) island divertor of simple models, typically developed in tokamaks, relating

E

r

in the SOL to the sheath potential drop gradient at the target. Additionally, we investigate the effect of the edge

E

r

shear on the reduction of density fluctuation amplitude, a well-established phenomenon according to the existing bibliography. The main diagnostic for measurements in the SOL is a V-band Doppler reflectometer that can provide the measurement of the

E

r

and density fluctuations with good spatial resolution. 3D measurements of divertor parameters have been carried out using infrared cameras, with the exponential decay length of the divertor heat flux (

λ

q

) resulting in a suitable proxy for the model-relevant

λ

T

, the exponential decay length of the temperature at the divertor. In the investigated attached regimes, it is shown for the first time that the formation of the

E

r

in the SOL depends on parameters at the divertor, following a

E

r

∝

T

e

/

λ

q

qualitatively similar to that found in a tokamak. Then, from the analyzed plasmas, the observed

E

r

shear at the edge is linked to a moderate local reduction of the amplitude of density fluctuations.
Fluctuating kinetic theory and fluctuating hydrodynamics of aligning active particles: the dilute limit
Authors: Feliachi Ouassim , Besse Marc , Nardini Cesare , Barré Julien
Published: November 2022

Kinetic and hydrodynamic theories are widely employed for describing the collective behavior of active matter systems. At the fluctuating level, these have been obtained from explicit coarse-graining procedures in the limit where each particle interacts weakly with many others, so that the total forces and torques exerted on each of them is of order unity at all times. Such limit is however not relevant for dilute systems that mostly interact via alignment; there, collisions are rare and make the self-propulsion direction to change abruptly. We derive a fluctuating kinetic theory, and the corresponding fluctuating hydrodynamics, for aligning self-propelled particles in the limit of dilute systems. We discover that fluctuations at kinetic level are not Gaussian and depend on the interactions among particles, but that only their Gaussian part survives in the hydrodynamic limit. At variance with fluctuating hydrodynamics for weakly interacting particles, we find that the noise variance at hydrodynamic level depends on the interaction rules among particles and is proportional to the square of the density, reflecting the binary nature of the aligning process. The results of this paper, which are derived for polar self-propelled particles with polar alignment, could be straightforwardly extended to polar particles with nematic alignment or to fully nematic systems.
Unidirectional diphenylalanine nanotubes for dynamically guiding neurite outgrowth
Authors: Zu Lipeng , Shi Huiyao , Yang Jia , Zhang Chuang , Fu Yuanyuan , Xi Ning , Liu Lianqing , Wang Wenxue
Published: November 2022

Neural networks have been cultured in vitro to investigate brain functions and diseases, clinical treatments for brain damage, and device development. However, it remains challenging to form complex neural network structures with desired orientations and connections in vitro. Here, we introduce a dynamic strategy by using diphenylalanine (FF) nanotubes for controlling physical patterns on a substrate to regulate neurite-growth orientation in cultivating neural networks. Parallel FF nanotube patterns guide neurons to develop neurites through the unidirectional FF nanotubes while restricting their polarization direction. Subsequently, the FF nanotubes disassemble and the restriction of neurites disappear, and secondary neurite development of the neural network occurs in other direction. Experiments were conducted that use the hippocampal neurons, and the results demonstrated that the cultured neural networks by using the proposed dynamic approach can form a significant cross-connected structure with substantially more lateral neural connections than static substrates. The proposed dynamic approach for neurite outgrowing enables the construction of oriented innervation and cross-connected neural networks in vitro and may explore the way for the bio-fabrication of highly complex structures in tissue engineering.
Interactions between concerns for the environment and other sources of concern in 31 European countries
Authors: Marasco Addolorata , Romano Alessandro , Sotis Chiara
Published: November 2022

Understanding how different sources of concern interact in people’s mind is a question that has entertained generations of scholars. The finite-pool-of-worry (FPW) hypothesis states that humans have limited resources to worry, thus when they are worried about one issue they become less worried about other issues. Instead, the affect generalization theory (AGT) posits that an increased level of worry about one threat increases concerns about related threats. To this end, we adopt a Lotka–Volterra model to detect instances of AGT and FPW among worries for the environment, economy, safety, social issues and immigration in 31 European countries between 2012 and 2019 (Eurobarometer data). Consistently with AGT, we find that an increase in the concern for the environment often favors the growth of concerns for the economy. Meanwhile, consistently with FPW, an increase in the concerns for the economy and for other sources of worry, often pushes down concerns for the environment. Building on our results, we hypothesize the existence of a pyramid of worries. At the bottom of the pyramid lie worries like concerns for the economy, which generally predate other worries. Concerns for the environment lie at the very top of the pyramid as they are generally predated by other worries. Last, we find that AGT and FPW can coexist not only over time and across countries, but also as a result of an asymmetric interaction.
Process-based climate change assessment for European winds using EURO-CORDEX and global models
Authors: Wohland Jan
Published: November 2022

Wind energy is an important pillar of decarbonization strategies and potentially vulnerable to climate change. Existing wind climate change assessments rely on climate models but a systematic investigation of the global-to-regional climate modeling chain is missing. In this study, I highlight key limitations, namely (a) the differing representation of land use change in global and regional climate models which compromises comparability, and (b) the consistency of large-scale features along the global-to-regional climate modeling chain. To this end, I analyze the large European Coordinated Downscaling Experiment (EURO-CORDEX) ensemble (rcp85: N = 49; rcp45: N= 18; rcp26: N = 22) along with the driving global models (rcp85: N = 7; rcp45: N = 5; rcp26: N = 7), finding evidence that climate change reduces mean wind speeds by up to −0.8 m s−1 (offshore) and −0.3 m s−1 (onshore). I provide physical explanations for these changes by identifying two key drivers. First, onshore wind speeds drop in the driving global models in regions and scenarios with strong land use change but show no drop in EURO-CORDEX where land use is held constant. Second, offshore wind reductions follow decreases in the equator-to-pole temperature gradient remarkably well with correlations reaching around 0.9 in resource-rich European countries like Ireland, the United Kingdom and Norway, implying that arctic amplification is a severe risk for European offshore wind energy. My results suggest that earlier conclusions of negligible climate change impacts on wind energy might be premature if either land use changes strongly or polar amplification is at or above the range sampled in global climate models.
Computable lower bounds on the entanglement cost of quantum channels
Authors: Lami Ludovico , Regula Bartosz
Published: November 2022

A class of lower bounds for the entanglement cost of any quantum state was recently introduced in Lami and Regula (2023 Nature Physics) in the form of entanglement monotones known as the tempered robustness and tempered negativity. Here we extend their definitions to point-to-point quantum channels, establishing a lower bound for the asymptotic entanglement cost of any channel, whether finite or infinite dimensional. This leads, in particular, to a bound that is computable as a semidefinite program and that can outperform previously known lower bounds, including ones based on quantum relative entropy. In the course of our proof we establish a useful link between the robustness of entanglement of quantum states and quantum channels, which requires several technical developments such as showing the lower semicontinuity of the robustness of entanglement of a channel in the weak*-operator topology on bounded linear maps between spaces of trace class operators.
Excitation and power spectrum analysis of electromagnetic radiation for the plasma wake of reentry vehicles
Authors: TONG Jiachen , LI Haiying , XU Bin , WU Songyang , BAI Lu
Published: November 2022

The plasma wake of reentry vehicles has the advantages of extensive space range and long traceability, which provides new possibilities for the detection and monitoring of reentry vehicles. Based on the Zakharov model, this work investigates the excitation and power spectrum characteristics of electromagnetic radiation for the plasma wake of a typical reentry vehicle. With the aid of parametric decay instability, the excitation condition of electromagnetic radiation for a typical plasma wake is evaluated first. The power spectrum characteristics of electromagnetic radiation, including the effects of both the flight parameters and incident wave parameters are analyzed in detail. The results show that when the phenomenon of excited electromagnetic radiation occurs, plasma wakes closer to the bottom of the vehicle and with faster speeds require higher incident frequencies and thresholds of the electric field. As the frequency of the incident wave increases, peaks appear in the power spectra of plasma wakes, and their magnitudes increase gradually. The frequency shifts of the secondary peaks are equal, whereas, the peaks of the downshifted spectral lines are generally larger than those of the upshifted spectral lines. The work in this paper provides a new idea and method for the tracking of reentry vehicles, which has potential application value in the field of reentry vehicle detection.
Does renewable energy consumption reduce energy ecological footprint: evidence from China
Authors: Nan Yu , Sun Renjin , Mei He , Yue Sun , Yuliang Li
Published: November 2022

The modern economic growth paradigm relies heavily on natural endowments. Renewable energy as a permanent energy source has the potential to reduce the ecological footprint (EF). We adopt the Vector Autoregressive model to examine the impact of renewable energy consumption on the energy EF and use the quantile regression method to test the heterogeneity and asymmetry between energy EF and photovoltaic, wind energy, and biomass energy. The results show that renewable energy has a long-term negative impact on the EF, and for every 1% increase in renewable energy consumption, the energy EF will decrease by 2.91%. The contribution of renewable energy consumption to reducing the EF is 1.34% on average. There is no two-way Granger causality between renewable energy consumption and energy EF. The reduction effect of wind energy consumption on the energy EF varies the most, followed by biomass energy and photovoltaic. In addition, under different energy EF distribution conditions, the impact of photovoltaic or wind energy or biomass energy consumption on the energy EF is different.
Morrey regularity theory of Rivière’s equation
Authors: Du Hou-Wei , Kang Yu-Ting , Wang Jixiu
Published: November 2022

This note is devoted to developing Morrey regularity theory for the following system of Rivière

−
Δ
u
=
Ω
⋅
∇
u
+
f

in 

B

2

,

\begin{equation*} -\Delta u=\Omega \cdot \nabla u+f \qquad \text {in }B^{2}, \end{equation*}

under the assumption that

f
f

belongs to some Morrey space. Our results extend the

L
p

L^p

regularity theory of Sharp and Topping [Trans. Amer. Math. Soc. 365 (2013), pp. 2317–2339], and also generalize a Hölder continuity result of Wang [Calc. Var. Partial Differential Equations 56 (2017), Paper No. 23, 24] on harmonic mappings. Potential applications of our results are also possible in second order conformally invariant geometrical problems as that of Wang [Calc. Var. Partial Differential Equations 56 (2017), Paper No. 23, 24].
Cup product in bounded cohomology of negatively curved manifolds
Authors: Marasco Domenico
Published: November 2022

Let

M
M

be a negatively curved compact Riemannian manifold with (possibly empty) convex boundary. Every closed differential

2
2

-form

ξ
∈

Ω
2

(
M
)

\xi \in \Omega ^2(M)

defines a bounded cocycle

c
ξ

∈

C
b
2

(
M
)

c_\xi \in C_b^2(M)

by integrating

ξ
\xi

over straightened

2
2

-simplices. In particular Barge and Ghys [Invent. Math. 92 (1988), pp. 509–526] proved that, when

M
M

is a closed hyperbolic surface,

Ω
2

(
M
)

\Omega ^2(M)

injects this way in

H
b
2

(
M
)

H_b^2(M)

as an infinite dimensional subspace. We show that the cup product of any class of the form

[

c
ξ

]

[c_\xi ]

, where

ξ
\xi

is an exact differential 2-form, and any other bounded cohomology class is trivial in

H
b

∙

(
M
)

H_b^{\bullet }(M)

.
A Latent Class Analysis of Perceived Barriers to Help-seeking Among People with Alcohol Use Problems Presenting for Telephone-delivered Treatment
Authors: Grigg Jasmin , Manning Victoria , Cheetham Ali , Youssef George , Hall Kate , Baker Amanda L , Staiger Petra K , Volpe Isabelle , Stragalinos Peta , Lubman Dan I
Published: November 2022

Aims

Despite the magnitude of alcohol use problems globally, treatment uptake remains low. This study sought to determine the proportion of people presenting to telephone-delivered alcohol treatment who are first-time help-seekers, and explored perceived barriers to help-seeking to understand the barriers this format of treatment may help to address.

Methods

Secondary analysis of baseline data from a randomized controlled trial of a telephone-delivered intervention for alcohol use problems. Latent class analysis (LCA) identified participant profiles according to self-reported barriers to alcohol treatment.

Results

Participants’ (344) mean age was 39.86 years (SD = 11.36, 18–73 years); 51.45% were male. Despite high alcohol problem severity (Alcohol Use Disorder Identification Test: mean = 21.54, SD = 6.30; 63.37% probable dependence), multiple barriers to accessing treatment were endorsed (mean = 5.64, SD = 2.41), and fewer than one-third (29.36%) had previously accessed treatment. LCA revealed a two-class model: a ‘low problem recognition’ class (43.32%) endorsed readiness-for-change and attitudinal barriers; a ‘complex barriers’ class (56.68%) endorsed stigma, structural, attitudinal and readiness-to-change barriers, with complex barrier class membership predicted by female sex (adjusted OR = 0.45, 95% CI 0.28, 0.72) and higher psychological distress (adjusted OR = 1.13, 95% CI 1.08, 1.18).

Conclusion

The majority of people accessing this telephone-delivered intervention were new to treatment, yet had high alcohol problem severity. Two distinct profiles emerged, for which telephone interventions may overcome barriers to care and tailored approaches should be explored (e.g. increasing problem awareness, reducing psychological distress). Public health strategies to address stigma, and raise awareness about the low levels of drinking that constitute problem alcohol use, are needed to increase help-seeking.
Place-Based Bias in Environmental Scholarship Derived from Social–Ecological Landscapes of Fear
Authors: Gadsden Gabriel I , Golden Nigel , Harris Nyeema C
Published: November 2022

Historical perspectives (e.g., moments of social, political, and economic significance) are increasingly relevant for developing insights into landscape change and ecosystem degradation. However, the question of how to incorporate historical events into ecological inquiry is still under development, owing to the evolving paradigm of transdisciplinary thinking between natural science and the humanities. In the present article, we call for the inclusion of negative human histories (e.g., evictions of communities and environmental injustices) as important factors that drive landscape change and shape research questions relevant to environmental conservation. We outline the detrimental effects of conservationists not addressing negative human histories by likening this social phenomenon to the ecological concept of landscapes of fear, which describes how not acknowledging these histories produces a landscape that constrains where and how research is conducted by scientists. Finally, we provide three positive recommendations for scholars or practitioners to address the manifestation of historic place-based bias in ecological research. What we call the social–ecological landscapes of fear provides a conceptual framework for more inclusive practices in ecology to increase the success of environmental and conservation goals.
A Half Century of Student Data Reveals the Professional Impacts of a Biology Field Course
Authors: Arcila Hernández Lina M , Mittan-Moreau Cinnamon S , Lamb Todd , Holmes Katherine D , McDonald Coby A , Zamudio Kelly R , Ballen Cissy J
Published: November 2022

Field courses provide learning experiences that diversify curricula and inspire students. Despite these benefits, we still have much to learn about field course impacts on student outcomes and career trajectories. We used a 50-year longitudinal data set to compare career outcomes for graduate students who participated in a biology field course with those of students who did not. More broadly, we surveyed students to identify graduate experiences most useful to advancing their careers. We found that field course attendees coauthored more scientific publications than did nonattendees. Although the students in both groups graduated and continued on to scientific careers at similar rates, the students attending the field course became faculty at a higher rate. Survey data showed that field courses provide valuable opportunities to graduate students, including student-led environments and mentor feedback. Our findings underscore the importance of field courses as effective tools to train the next generation of scientists.
IBCOx-15 Bariatric surgery in patients with BMI greater than 70: analysis of the ACSNSQIP database
Authors: Romero-Velez G , Garcia Cabrera A T , Pechman D M , Flores F M , Moran-Atkin E , Choi J , Camacho D R
Published: November 2022

Background

Bariatric surgery offers patients short- and long-term benefits to their health and quality of life. Currently, we see more patients with superior body mass index (BMI) looking for these benefits. Evidence-based medicine is integral in the evaluation of risks versus benefit; however, data are lacking in this high-risk population.

Objectives

To assess the morbidity and mortality of patients with BMI 70 undergoing bariatric surgery.

Setting

University Hospital, Bronx, New York, USA using national database.

Methods

Using the American College of Surgeons-National Surgical Quality Improvement Project (ACS-NSQIP) database for years 2005 to 2016, we identified patients who underwent primary laparoscopic sleeve gastrectomy or laparoscopic Roux-en-Y gastric bypass. Patients with BMI ≥70 were assigned to the BMI ≥ 70 (BMI70+) cohort and less obese patients were assigned to the BMI < 70 (U70) cohort. Length of stay and 30-day morbidity and mortality were compared.

Results

A total of 163,413 patients underwent non-revisional bariatric surgery. Of those, 2322 had a BMI ≥ 70. BMI70+ was associated with increased mortality (0.4% versus 0.1%, P 5.0001), deep vein thrombosis (0.6% versus 0.3%, P 5.007), pulmonary (1.9% versus 0.5%, P 5.0001), renal (0.9% versus 0.2%, P 5.0001), and infectious complications (1.1% versus .4%, P 5 .0001). BMI 70+ patients had longer mean length of stay (2.6 versus 2.1 d, P 5.0001) and operative time (126.1 versus 114.5 min, P 5.0001). There was no statistically significant difference in the number of myocardial infarctions (0.1% versus 0.1%, P 5.319), pulmonary embolisms (0.3% versus 0.2%, P 5.596), and transfusion requirements (0.1% versus 0.1%, P 5.105) between groups.

Conclusions

Evaluation of risk and benefit is performed on a case-by-case basis, but evidence-based medicine is critical in empowering surgeons and patients to make informed decisions. The overall rate of morbidity and mortality for BMI 701+ patients undergoing bariatric surgery was increased over U70 patients but was still relatively low. Our study will allow surgeons to incorporate objective data into their assessment of risk for super-obese patients pursuing bariatric surgery.
IBC-Ox32 Streamlining preoperative risk assessment: counterintuitive results in the Bariatric patient
Authors: Silveira F C , Mitchell F G , Maranga G , Jenkins M , Pachter H L , Ren-Fielding C
Published: November 2022

Background

Bariatric surgical operations continue to be performed in high numbers nationally, thus it is important to identify factors associated with post-surgical complications. This study aims to identify preoperative risk factors associated with bariatric surgery mortality.

Methods

A retrospective analysis was conducted on the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database to determine the strength of association between pre-operative exposures and 30-day mortality following bariatric surgery. A total of 701,265 primary bariatric operations were registered between the years of 2015 and 2017, consisting of sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), adjustable gastric band (AGB), and duodenal switch (DS)

Results

From the 701,265 surgeries registered in the database, 636,286 had complete data points for the variables of interest and therefore were included in this analysis. The mean age of the cohort was 45.01 (SD= 11.96) years, mean BMI was 45.54 kg/m2 (SD=7.72), and 80.07% were female. Overall 30-day mortality was 0.10% (n=629). The association between the following preoperative variables and mortality within 30 days of bariatric surgery was not statistically significant: hyperlipidemia, history of pulmonary embolism, oxygen dependence, obstructive sleep apnea and history of venous stasis. Smoking status (AOR=1.38), insulin dependent diabetes (AOR=1.37) and the use of more than 3 hypertensive medications (AOR=1.30) were weakly associated with postoperative mortality (p<0.05; CI=95%). History of chronic obstructive pulmonary disease (COPD; AOR=2.00), partial functional dependency (AOR=2.09), renal insufficiency (AOR=1.63), dialysis (AOR=3.15), history of deep venous thrombosis (AOR=1.78), history of myocardial infarction (AOR=1.65) and history of cardiac surgery (AOR=1.87) were strongly associated with mortality (P<0.05; c.i. = 95%)

Conclusion

Bariatric surgery continues to be safe. Many factors that have traditionally been thought to contribute to mortality, such as diabetes, hypertension, smoking, and oxygen dependence may have little impact. Other variables such as previous heart surgery, functional dependency status and COPD may play a bigger role in adverse outcomes. While these associations do not determine causality, understanding the strength of them can guide physicians on preoperative risk assessment and care.
IBC-Ox34 Transit bipartition improves serum total testosterone levels in overweight and obese type-2 diabetic men and cures erectile dysfunction: short-term preliminary results
Authors: Taskin H E , Al M , Ozbek E
Published: November 2022

Introduction

In males, erectile dysfunction (ED) secondary to obesity is one of the most common cause of male sexual dysfunction, in our study we investigated the effect of bariatric surgery on male sex hormone, testosterone and sexual status of 99 overweight and obese men with type II diabetes who underwent a laparoscopic transit bipartition.

Methods

Ninety-nine patients with type-II diabetes mellitus (T2DM) and obesity who underwent transit bipartition in Hospital X were prospectively evaluated before and 6 months after the surgery for the serum total testosterone levels. Also, the erectile dysfunction was evaluated by using International Index of Erectile Function (IIEF) scoring system. In addition, all the patients had been evaluated in BMI categories of overweight (BMI 25-29), Class 1 Obese (30-35), Class 2 Obese (35-40) and morbidly obese (>40 kg/m2).

Results

Serum total testosterone (T) levels were assessed before and 6 months after TB in 99 male patients. Mean age was 45.7 and median serum total testosterone (T) levels before and after 6 months were 3.03 nmol/L (range: 0.38-8.44) and, 4.43 nmol/L (range 0.34-9.70) (min-max) respectively. Also, the patient's pre-operative and post-operative testosterone values and IIEF scores were calculated in every category of obesity (Table 1). Before and after bariatric surgery serum T levels were statistically significant (p<0.005).

Conclusion

In conclusion serum T levels and IIEF scores significantly improved after 6 months following bariatric surgery. This condition may explain improvement of erectile dysfunction following bariatric surgery. Larger and long-term studies are required to investigate these beneficial effects of surgery in patients with obesity and T2DM.
IBCOx_1 Do we really need to use staple line reinforcement to prevent leaks after sleeve gastrectomy?
Authors: Alhamdani A , Sufi P , Parmar C
Published: November 2022

Introduction

While some of systematic reviews inform us about the superiority of the stapler line reinforcement (SLR) over no reinforcement to prevent leaks in sleeve gastrectomy, the First Report from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) with 188,000 patients contradicts this with higher leak rates associated with SLR. The objective is to understand why the variation in the literature about the SLR in preventing leaks or not and how this relates to surgeon experience.

Methods

Literature review was performed and analysed to identify the type of the SLR used or not. This was compared with the leak site, stomach thickness and type of stapler thickness height used. The surgeon experience was also taken into account.

Results

The leak rates were mainly due to inappropriate use of the stapler colour (thickness) in relation to the SLR type and the stomach thickness. In one systematic review higher leak rates were found when inappropriate low staple height (blue stapler 1.8mm closure height) was used to include bovine SLR (1mm thickness) to staple the fundal area (1.5mm thickness). In another meta-analysis less leaks rates were noticed using the same buttressing material with a larger stapler (green or gold). Increase in surgeon experience was associated with decreased leak rate.

Conclusion

The inappropriate use of the stapler height with the SLR contributes to the leak and can explain the variation in the literature. The surgeon experience associated with decrease leak rates.
IBCOx-8 Bile reflux after laparoscopic mini-gastric bypass; Is it really a major concern?
Authors: Foula M S
Published: November 2022

Background

Laparoscopic mini gastric bypass MGB, first performed in late 1990s, become a popular bariatric procedure with proven comparable efficiency. Its popularity can be explained by many factors including: its technical simplicity and efficacy in weight loss compared to RYGB, its superiority in controlling metabolic syndrome compared to restrictive procedures and its efficacy as revision surgery for failed restrictive procedures. However, many debates still exist among bariatric surgery experts regarding its complications; mainly bile reflux and its consequences.

We presented our experience, as a tertiary university institute in dealing with bile reflux complications after laparoscopic mini gastric bypass that necessitated endoscopic and/or operative interventions.

Methods

This is a retrospective study of all cases who were admitted in a tertiary hospital because of bile reflux related complications in one year duration.

Results

Three cases were admitted because of bile reflux complications. The first case presented by hemorrhagic shock due to massive hemorrhage at a marginal ulcer after 26 days of mini gastric bypass. The second case was re-operated electively because of intractable bile reflux after failure of medical treatment. The third case presented with peritonitis on top of perforated marginal ulcer seven month after mini gastric bypass.

Conclusion

Despite its claimed safety and efficacy, laparoscopic mini gastric bypass is not the procedure of no-morbidities. Incidence of postoperative bile reflux is under-estimated. All patients should undergo a regular endoscopy to assess it even if asymptomatic.
IBC-Ox22 Greater Adherence to Mediterranean Diet leads to longer term weight loss
Authors: Simpson T , Billy H
Published: November 2022

We were able to obtain dietary data of 134 weight loss surgery patients with an average follow up of five years with annual scoring of the 9 point Mediterranean Diet. The closer adherence to the MD showed more weight loss than those who had not.

Background

The Mediterranean Diet has been associated with decreased all cause mortality for those who adhere strongly to it, as well as decreased risk of heart disease, and cancer. The diet is rich in polyphenols with fruits, vegetables, legumes, fish, mono-unsaturated fats, whole grains, while minimizing dairy, meat and poultry, and some moderate alcohol consumption.

Methods

Pre operatively all bariatric patients patients were counseled about the Mediterranean diet, how to score the diet, and adherence to the diet was reemphasized at their follow ups. Annually they were asked to fill out their scores. We looked at other diet plans that some of the patients reported (low carbohydrate, weight watchers) and the results were not significant.

Results

Of the 134 patients there were 65 which had scores of 5 points or more and showed an absolute reduction in weight of 54% total weight loss on average, vs those of 1-3 who had 32% total weight loss (total of 60 patients). The remaining 9 patients who escorted 4 points had a wide spread of weight loss that could not be calculated (these patients predominantly followed a self-described low-carbohydrate diet). There was no difference in weight loss regarding the type of surgery that the patient had (Lap-Band (N=74) vs Gastric Sleeve (N=50) vs Gastric bypass (N=10). Nor was there any difference in weight loss when measuring physical activity.

Using the 9 point scale of the Mediterranean Diet those who had greater than 5 of the 9 points on the MD had greater weight loss over five years than those who were 0-3. Those who scored 4 points were indeterminate.

Conclusions

The Mediterranean Diet scale provides a quick and easy guide, providing targets for patients (example, less than 4 ounces per day of poultry or meat is a point, more is 0 points). The emphasis on a post operative diet for health, as opposed to weight loss, inadvertently provided a good model for post operative weight loss.
Location, location, location: myelin repair and proximity to ventricular CSF in multiple sclerosis
Authors: Gauthier Susan A
Published: November 2022

This scientific commentary refers to ‘Periventricular remyelination failure in multiple sclerosis: a substrate for neurodegeneration’ by Tonietto et al. (https://doi.org/10.1093/brain/awac334).
Comparison of CRISPR-Cas9-mediated megabase-scale genome deletion methods in mouse embryonic stem cells
Authors: Miyata Masayuki , Yoshida Junko , Takagishi Itsuki , Horie Kyoji
Published: November 2022

The genome contains large functional units ranging in size from hundreds of kilobases to megabases, such as gene clusters and topologically associating domains. To analyse these large functional units, the technique of deleting the entire functional unit is effective. However, deletion of such large regions is less efficient than conventional genome editing, especially in cultured cells, and a method that can ensure success is anticipated. Here, we compared methods to delete the 2.5-Mb Krüppel-associated box zinc finger protein (KRAB-ZFP) gene cluster in mouse embryonic stem cells using CRISPR-Cas9. Three methods were used: first, deletion by non-homologous end joining (NHEJ); second, homology-directed repair (HDR) using a single-stranded oligodeoxynucleotide (ssODN); and third, HDR employing targeting vectors with a selectable marker and 1-kb homology arms. NHEJ-mediated deletion was achieved in 9% of the transfected cells. Inversion was also detected at similar efficiency. The deletion frequency of NHEJ and HDR was found to be comparable when the ssODN was transfected. Deletion frequency was highest when targeting vectors were introduced, with deletions occurring in 31–63% of the drug-resistant clones. Biallelic deletion was observed when targeting vectors were used. This study will serve as a benchmark for the introduction of large deletions into the genome.
Exploring the structure of internal combustion engine and battery electric vehicles: implications for the architecture of the automotive industry
Authors: Murmann Johann Peter , Schuler Benedikt Alexander
Published: November 2022

How will the technological shift from internal combustion engine vehicles (ICEVs) to battery electric vehicles (BEVs) change the architecture of the automotive industry? To explore this question, we systematically compare the technological structure of ICEVs and BEVs using data from large incumbent automobile companies and start-ups. While our analysis based on technical descriptions and design structure matrices suggests that the power train of BEVs is structurally simpler compared to the power train of ICEVs, BEVs are slightly less modular than ICEVs. We discusss important strategic implications of this finding for incumbent firms and start-ups.
An exotic allele of barley EARLY FLOWERING 3 contributes to developmental plasticity at elevated temperatures
Authors: Zhu Zihao , Esche Finn , Babben Steve , Trenner Jana , Serfling Albrecht , Pillen Klaus , Maurer Andreas , Quint Marcel
Published: November 2022

Increase in ambient temperatures caused by climate change affects various morphological and developmental traits of plants, threatening crop yield stability. In the model plant Arabidopsis thaliana, EARLY FLOWERING 3 (ELF3) plays prominent roles in temperature sensing and thermomorphogenesis signal transduction. However, how crop species respond to elevated temperatures is poorly understood. Here, we show that the barley ortholog of AtELF3 interacts with high temperature to control growth and development. We used heterogeneous inbred family (HIF) pairs generated from a segregating mapping population and systematically studied the role of exotic ELF3 variants in barley temperature responses. An exotic ELF3 allele of Syrian origin promoted elongation growth in barley at elevated temperatures, whereas plant area and estimated biomass were drastically reduced, resulting in an open canopy architecture. The same allele accelerated inflorescence development at high temperature, which correlated with early transcriptional induction of MADS-box floral identity genes BM3 and BM8. Consequently, barley plants carrying the exotic ELF3 allele displayed stable total grain number at elevated temperatures. Our findings therefore demonstrate that exotic ELF3 variants can contribute to phenotypic and developmental acclimation to elevated temperatures, providing a stimulus for breeding of climate-resilient crops.