bluuebunny/crossref_metadata_2025 huggingface dataset:
Cervical slide tracheoplasty in adults with laryngotracheal stenosis
Authors: Redmann Andrew J. , Rutter Michael J. , de Alarcon Alessandro , Hart Catherine K. , Manning Amy , Smith Matthew , Khosla Sid M.
Published: December 2018

Objectives

1) Evaluate success rates for adults undergoing cervical slide tracheoplasty. 2) Examine complication rates of slide tracheoplasty in adults.

Methods

A retrospective cohort of adults > 21 years of age undergoing cervical slide tracheoplasty for tracheal stenosis between October 2011 and August 2017 was reviewed. Comorbidities, stenosis grade, etiology of stenosis, primary versus revision surgery, complications, and number of adjunct endoscopic procedures required postoperatively were evaluated.

Results

Nineteen patients (63% female) underwent cervical slide tracheoplasty during the study period (median age 30 years, range 21–70). The most common etiology of stenosis was iatrogenic (68%), followed by congenital etiologies (26%). Fifty‐eight percent of patients had undergone a previous open airway procedure. Thirty‐nine percent were tracheostomy‐dependent prior to surgery, and the remainder had severe exercise intolerance. Sixty‐three percent were successfully extubated on the operating room table at the end of the procedure. Six (32%) patients experienced surgical complications, including one anastomotic dehiscence, three neck abscesses requiring incision and drainage (I&D), and replacement of adjunctive airway device in two patients. Seventy percent of the patients required ≥ 1 endoscopic dilation in the first 12 months following surgery, with a median of one (range 1–8) procedure. At most recent follow‐up (median 8 months, range 4–64 months), 18 of 19 (95%) of patients had minimal airway symptoms without need for tracheostomy. The one patient who was not decannulated expired of a presumed cardiac event prior to decannulation.

Conclusion

Cervical slide tracheoplasty is an excellent reconstructive option for adult patients with tracheal stenosis, including those with history of previous airway reconstruction.

Level of Evidence

4 Laryngoscope, 129:818–822, 2019
The presence of eosinophil aggregates correlates with increased postoperative prednisone requirement
Authors: Tajudeen Bobby A. , Ganti Ashwin , Kuhar Hannah N. , Mahdavinia Mahboobeh , Heilingoetter Ashley , Gattuso Paolo , Ghai Ritu , Batra Pete S.
Published: December 2018

Objectives/Hypothesis

Failure after sinus surgery is multifactorial, but often due to recurrence of inflammatory mucosal disease. Postoperative steroid requirements for controlling mucosal inflammation may provide insight into predicting which patients require more aggressive medical therapy to prevent disease relapse.

Study Design

Retrospective chart review.

Methods

A review was performed of patients who underwent functional endoscopic sinus surgery (FESS) for refractory chronic rhinosinusitis (CRS). Sino‐Nasal Outcome Test‐22 scores and cumulative prednisone dose (milligrams) requirements at 1, 3, and 6 months postoperatively were reviewed. A structured histopathology report of 11 variables was accessed to correlate histopathology with postoperative steroid requirements.

Results

One hundred one patients were reviewed including 42 CRS with nasal polyps and 59 CRS without nasal polyps patients. CRS patients with eosinophilia required greater cumulative steroids to control disease at 1‐, 3‐, and 6‐month postoperative intervals (P < .026, P < .007, P < .013, respectively) compared to patients without eosinophilia. Patients with tissue eosinophil aggregates required the highest cumulative steroids at 1‐, 3‐, and 6‐month postoperative intervals (P < .003, P < .001, P < .001, respectively). When removing patients with eosinophil aggregates from the eosinophilia group, no difference persisted between patients with eosinophilia and those without eosinophilia at all intervals (P = .664, P = .735, P = .800, respectively). No other histopathology variable correlated with postoperative steroid requirement.

Conclusions

Tissue eosinophil aggregates appear to be the largest driving factor for increased prednisone requirements after sinus surgery to control mucosal disease than mere presence of eosinophils. This key finding may identify patients at high risk for failure after sinus surgery and guide more proactive postoperative management.

Level of Evidence

4 Laryngoscope, 129:794–799, 2019
Carcinoma presenting as idiopathic anterior glottic webs: A case series
Authors: Ramaswamy Apoorva T. , Tian Lisa , Bock Jonathan M. , Klein Adam M. , Pitman Michael J.
Published: December 2018

An anterior glottic web is an abnormal fusion of the anterior aspect of the membranous vocal folds. Noncongenital glottic webs are usually iatrogenic from intubation or laryngeal surgery. We present six adult patients whose initial in‐office diagnoses were consistent with “idiopathic” benign anterior glottic webs as determined by three laryngologists (a.m.k., j.m.b., m.j.p.). Further evaluation revealed the diagnoses of laryngeal squamous cell carcinoma in all cases. The high risk of malignancy in cases of idiopathic anterior glottic web necessitates biopsy for tissue diagnosis of all such lesions.

Laryngoscope, 129:2118–2120, 2019
Improved microwave attenuator topology minimizing the number of control voltages
Authors: Longhi Patrick E. , Colangeli Sergio , Ciccognani Walter , Limiti Ernesto
Published: December 2018

This letter presents an improved circuit topology to minimize the number of external control voltages that are required to set the state of an N‐bit microwave digital attenuator. An alternative method to connect the control signal is proposed. Typically, the control signal is connected to the gate terminal of the field effect transistor while the source terminal is DC grounded. Here, the control signal is applied to the source terminal of the field effect transistor while the gate is connected to a fixed reference voltage. In this way, only one control voltage is necessary to set the state of single attenuator cell vs two control voltages required in the typical case. The proposed method becomes particularly beneficial as the number of bits increases (ie, >4). The topology has been validated through design, realization, and testing of a 5‐bit Monolithic Microwave Integrated Circuit (MMIC) attenuator operating over the full C‐band (4‐8 GHz).
A new quantizing insulator soldering technology scheme for microwave module
Authors: Tian Fei‐Fei , Zhou Ming , Zhang Jun Zhi
Published: December 2018

A new quantizing technology scheme of insulator soldering was presented comparing with traditional soldering technology using solder paste, based on utilization of solid solder ring and the consideration of insulator mounting hole design on the microwave module shell. The X‐ray test on void ratio of insulator soldering shows that there exists no penetration void and the void ratio is below 5%. According to the leak standard A4 of GJB 548B‐1014.2, the standard leak rate of microwave module after the insulator soldering was below 5 × 10−9(Pa·m3)/s. After 10 cycles of temperature shock test ranging from −55°C to 125°C, the standard leak rate of microwave module was still below 5 × 10−9 (Pa·m3)/s. In comparison with traditional insulator soldering technology using solder paste, through utilization of solid solder ring and the design of insulator mounting hole, this new technology quantized the soldering of insulator so as to resolve the existing defects of traditional insulator soldering such as solder overflow, high void ratio, shortcut and channel blocking. The quantized insulator sealed soldering technology ensured the reliability, air impermeability, uniformity and beautifulness of soldering meanwhile improved operators' efficiency.
Mitigating the effects of time‐domain ringing in band‐notched UWB antennas
Authors: Hong Sun K. , Park Hong Soo
Published: December 2018

There is interest in designing UWB antennas with band‐notches to reject other narrowband communication frequencies to avoid interference. However, such band‐notched characteristics inherently cause ringing in the time‐domain, thereby distorting the transmitted (or received) UWB pulses. The level of distortion may depend on the bandwidth and strength of the band‐notch, and it may degrade the performance of a short‐pulse based UWB system. This letter examines the ringing effects of band‐notches in the time‐domain and proposes a method to mitigate the ringing effect in the received signal using the E‐pulse technique.
Design and manufacture of lowpass microstrip filter with high conductivity graphene films
Authors: Zhou Wenqing , Liu Chengguo , Huang Guan‐Long , Xia Wei , Zhang Jingwei , He Daping , Wu Zhi
Published: December 2018

The design and manufacture of lowpass microstrip filter with high conductivity graphene films (HCGF) is reported, which is a proven work of the feasibility of HCGF used in microwave devices for wireless communications. The filter is designed as a fifth order Chebyshev step‐impedance lowpass microstrip filter operating at 2.5 GHz, its conduct strip is the novel HCGF. Based on the parametric study in the design, the optimum structure parameters of the filter are selected to fabricate the filters using HCGF with conductivity up to 1.1 × 106 S/m. It is fabricated with precise and efficient method of laser engraving technique. The test results show that in‐band microwave signals can transmit through the proposed HCGF filter effectively with insertion loss of 0.68 dB. The results in this paper show that HCGF filter has good performance comparable characteristics of the traditional copper filters.
Three‐dimensional holographic imaging using data collected over cylindrical apertures
Authors: Amineh Reza K. , Ravan Maryam , Wu Hailun , Kasturi Aakarsha
Published: December 2018

The previously proposed near‐field holographic imaging algorithms are based on the data collected over rectangular apertures. In this letter, we propose an approach for three‐dimensional near‐field holographic imaging with data collected over cylindrical apertures. Circular deconvolution is employed to deal with the periodicity of the functions along the azimuthal direction.
A modified interdigital EBG reflector for wireless body area network applications
Authors: Rano Dinesh , Hashmi Mohammad
Published: December 2018

A modified, compact, and via‐less interdigital electromagnetic band gap cell intended for wearable application at medical body area network (MBAN), and Wi‐Fi bands is reported in this article. The reflection phase of the proposed EBG unit cell is then investigated to design a reflector consisting of 3 × 2 array of EBG cells for an efficient radiation of a planar monopole antenna. The size and shape of the EBG unit cell has been designed in such a way that it achieves 0° reflection phase with minimum dimension of 14.3 and 15.34 mm along x‐axis and y‐axis, respectively. Subsequently, the surface wave rejection ability of the EBG incorporated ground plane is also studied and presented in this article. A planar monopole antenna incorporating the proposed EBG reflector at MBAN frequency exhibits gain, and efficiency of 6.4 dB, and 95%, respectively, and has net dimension of 34 mm × 55 mm × 4.67 mm along x‐axis, y‐axis, and z‐axis, respectively. Finally, specific absorption rate (SAR) analysis carried out for one layer, homogenous model, and three‐layer, heterogeneous model, shows a considerable reduction in SAR values for 0.5 W of power fed to the antenna. The effectiveness of the proposed approach is demonstrated through good agreement between the simulated and the experimental results.
Realization of modified Luneburg lens antenna using quasi‐conformal transformation optics and additive manufacturing
Authors: Biswas Soumitra , Lu Aric , Larimore Zachary , Parsons Paul , Good Austin , Hudak Nicholas , Garrett Benjamin , Suarez John , Mirotznik Mark S.
Published: December 2018

We demonstrate a new method for realizing modified Luneburg lens antennas with nearly continuously graded permittivity profiles in three‐dimensions. The method used a quasi‐conformal transformation optics (QCTO) approach to modify the geometry and permittivity of a spherical Luneburg lens to have a flat surface for convenient integration of antenna feeds. The modified lens was then fabricated using Fused Deposition Modeling (FDM) printing with an effective media approach that employs space‐filling curves. The method was validated by designing and fabricating a modified Luneburg lens antenna designed to operate in the Ka‐band. The antenna performance of the sample was measured experimentally and shown to compare well to predicted results using full wave simulations. The device was able to achieve a reasonably high degree of beam steering (ie, −55° to +55°) over the entire Ka‐band. We believe this new approach provides a cost‐effective and scalable means of realizing practical passive beam steering lenses that operate over a broad range of frequencies.
Design of a high‐gain wideband antenna using double‐layer metasurface
Authors: Asadpor Loghman , Sharifi Ghader , Rezvani Mirhamed
Published: December 2018

A wideband antenna is studied in this paper using a multi‐layer metasurface structure and implementing a periodic array for enhancing the gain. The performance of the multilayer antenna is improved by using a sub‐wavelength Fabry‐Perot cavity (FPC). The feeding and main radiation patches of the microstrip antenna are placed separately on two substrates, which are stacked on top of each other without an air‐gap in between. Two other substrates are placed within an optimized distance on top of the microstrip antenna. This structure, which has a double‐sided periodic array configuration, includes a capacitive artificial impedance surface (AIS) on one side, and an inductive partially reflective surface (PRS) on the other side of the substrates. Making use of this configuration increases the gain up to 18 dBi and widens the frequency bandwidth. Moreover, measurement results indicate a frequency range from 10.8 GHz to 15 GHz with an S11 less than −10 dB.
Simultaneous estimation and segmentation from projection data in dynamic PET
Authors: Cui Jianan , Yu Haiqing , Chen Shuhang , Chen Yunmei , Liu Huafeng
Published: December 2018

Purpose

Dynamic positron emission tomography (PET) is known for its ability to extract spatiotemporal information of a radio tracer in living tissue. Information of different functional regions based on an accurate reconstruction of the activity images and kinetic parametric images has been widely studied and can be useful in research and clinical setting for diagnosis and other quantitative tasks. In this paper, our purpose is to present a novel framework for estimating the kinetic parametric images directly from the raw measurement data together with a simultaneous segmentation accomplished through kinetic parameters clustering.

Method

An iterative framework is proposed to estimate the kinetic parameter image, activity map and do the segmentation simultaneously from the complete dynamic PET projection data. The clustering process is applied to the kinetic parameter variable rather than to the traditional activity distribution so as to achieve accurate discrimination between different functional areas. Prior information such as total variation regularization is incorporated to reduce the noise in the PET images and a sparseness constraint is integrated to guarantee the solution for kinetic parameters due to the over complete dictionary. Alternating direction method of multipliers (ADMM) method is used to solve the optimization problem. The proposed algorithm was validated with experiments on Monte Carlo‐simulated phantoms and real patient data. Symbol error rate (SER) was defined to evaluate the performance of clustering. Bias and variance of the reconstruction activity images were calculated based on ground truth. Relative mean square error (MSE) was used to evaluate parametric results quantitatively.

Result

In brain phantom experiment, when counting rate is 1 × 106, the bias (variance) of our method is 0.1270 (0.0281), which is lower than maximum likelihood expectation maximization (MLEM) 0.1637 (0.0410) and direct estimation without segmentation (DE) 0.1511 (0.0326). In the Zubal phantom experiment, our method has the lowest bias (variance) 0.1559 (0.0354) with 1 × 105 counting rate, compared with DE 0.1820 (0.0435) and MLEM 0.3043 (0.0644). As for classification, the SER of our method is 18.87% which is the lowest among MLEM + k‐means, DE + k‐means, and kinetic spectral clustering (KSC). Brain data with MR reference and real patient results also show that the proposed method can get images with clear structure by visual inspection.

Conclusion

In this paper, we presented a joint reconstruction framework for simultaneously estimating the activity distribution, parametric images, and parameter‐based segmentation of the ROIs into different functional areas. Total variation regularization is performed on the activity distribution domain to suppress noise and preserve the edges between ROIs. An over complete dictionary for time activity curve basis is constructed. SER, bias, variance, and MSE were calculated to show the effectiveness of the proposed method.
Two‐echelon distribution systems with random demands and storage constraints
Authors: Federgruen Awi , Guetta C. Daniel , Iyengar Garud
Published: December 2018

We consider a general two‐echelon distribution system consisting of a depot and multiple sales outlets, henceforth referred to as retailers, which face random demands for a given item. The replenishment process consists of two stages: the depot procures the item from an outside supplier, while the retailers' inventories are replenished by shipments from the depot. Both of the replenishment stages are associated with a given facility‐specific leadtime. The depot as well as the retailers faces a limited inventory capacity. Inventories are reviewed and orders are placed on a periodic basis. When a retailer runs out of stock, unmet demand is backlogged.

We propose a new approach to the above class of dynamic programming models based on Lagrangian relaxation. Every choice of the vector of Lagrange multipliers generates a lower bound via the solution of a single dynamic program (DP) with a one‐dimensional state‐space. The best such bound is obtained by maximizing over the vector of multipliers. The strategy that is optimal for this (maximal) lower bound DP employs an (s, S) ordering policy (generally, with time‐dependent policy parameters). To arrive at an upper bound and an implementable heuristic, this (s, S) policy is paired with one of several possible allocation policies that allocate the system‐wide inventory across the different facilities.

We report on an extensive numerical study with close to 14 000 instances which evaluates the accuracy of the lower bound and the optimality gap of the various heuristic policies. The study reveals that the lower bound and the heuristic strategy that is constructed on its basis perform exceedingly well, almost across the entire parameter spectrum, including instances where demands are rather volatile or the average cycle time between consecutive orders is relatively large. The exception arises when storage at the depot is as expensive as at the retailer level and the retailers have large storage capacities.
Coupled Atmosphere‐Fire Simulations of the Black Saturday Kilmore East Wildfires With the Unified Model
Authors: Toivanen Jussi , Engel Chermelle B. , Reeder Michael J. , Lane Todd P. , Davies Laura , Webster Stuart , Wales Scott
Published: December 2018

A model for the spread of a wildfire is developed within the U.K. Met Office Unified Model (UM) and used to simulate the Kilmore East fire complex (in southeastern Australia) on Black Saturday (7 February 2009). The UM is configured with four nests with horizontal grid spacings of 4 km, 1.5 km, 444 m, and 144 m. In the first simulation, the UM simply provides predictions of the near‐surface conditions for the wildfire model with no feedbacks to the atmosphere from the fire. In the second, the atmosphere and fire are coupled, allowing the fire to affect the local‐scale weather. The agreement between the coupled simulation and the observed fire behavior is reasonably good. For example, the area burnt is approximately 80% of the actual area burnt. However, such agreement is achieved only by coupling the fire to the atmosphere and, importantly, by igniting 18 additional fires at the times and places the long‐range transport of burning material (spotting) was observed. Without coupling the burnt area is about half of that observed. The calculations reported here suggest that the behavior and spread of fires like the Kilmore East fire are predictable but only when long‐range spotting is included and the atmosphere and fires are coupled. Additional numerical experiments with coarser grids suggest that, although the details of the fire spread are lost, a grid spacing of 1.5 km may be sufficient to simulate the main features of the fire spread.
Isaac M. Held Receives 2018 Roger Revelle Medal
Authors:   AGU
Published: December 2018

Isaac M. Held was awarded the 2018 Roger Revelle Medal at the AGU Fall Meeting Honors Ceremony, held on 12 December 2018 in Washington, D. C. The medal is for “outstanding contributions in atmospheric sciences, atmosphere-ocean coupling, atmosphere-land coupling, biogeochemical cycles, climate or related aspects of the Earth system.”
High‐Resolution Observations of Subsurface Fronts and Alongshore Bottom Temperature Variability Over the Inner Shelf
Authors: Connolly Thomas P. , Kirincich Anthony R.
Published: December 2018

Circulation patterns over the inner continental shelf can be spatially complex and highly variable in time. However, few studies have examined alongshore variability over short scales of kilometers or less. To observe inner‐shelf bottom temperatures with high (5‐m) horizontal resolution, a fiber‐optic distributed temperature sensing system was deployed along a 5‐km‐long portion of the 15‐m isobath within a larger‐scale mooring array south of Martha's Vineyard, MA. Over the span of 4 months, variability at a range of scales was observed along the cable over time periods of less than a day. Notably, rapid cooling events propagated down the cable away from a tidal mixing front, showing that propagating fronts on the inner shelf can be generated locally near shallow bathymetric features in addition to remote offshore locations. Propagation velocities of observed fronts were influenced by background tidal currents in the alongshore component and show a weak correlation with theoretical gravity current speeds in the cross‐shore component. These events provide a source of cold, dense water into the inner shelf. However, differences in the magnitude and frequency of cooling events at sites separated by a few kilometers in the alongshore direction suggest that the characteristics of small‐scale variability can vary dramatically and can result in differential fluxes of water, heat, and other tracers. Thus, under stratified conditions, prolonged subsurface observations with high spatial and temporal resolution are needed to characterize the implications of three‐dimensional circulation patterns on exchange, especially in regions where the coastline and isobaths are not straight.
The Vertical Momentum Budget of Shallow Cumulus Convection: Insights From a Lagrangian Perspective
Authors: Tian Yang , Kuang Zhiming , Singh Martin S. , Nie Ji
Published: December 2018

A Lagrangian Particle Dispersion Model is embedded into large eddy simulations to diagnose the responses of shallow cumulus convection to a small‐amplitude large‐scale temperature perturbation. The Lagrangian framework allows for a decomposition of the vertical momentum budget and diagnosis of the forces that regulate cloudy updrafts. The results are used to shed light on the parameterization of vertical velocity in convective schemes, where the treatment of the effects of entrainment as well as buoyancy‐induced and mechanically induced pressure gradients remains highly uncertain. We show that both buoyancy‐induced and mechanically induced pressure gradients are important for the vertical momentum budget of cloudy updrafts, whereas the entrainment dilution term is relatively less important. Based on the analysis of the dominant force balance, we propose a simple model to derive the perturbation pressure gradient forces. We further illustrate that the effective buoyancy and dynamic perturbation pressure can be approximated to a good extent using a simple cylindrical updraft model given the cloud radius. This finding has the potential for improving the parameterization of vertical velocity in convective schemes and the development of a unified scheme for cumulus convection.
Evaluating Marine Stratocumulus Clouds in the CNRM‐CM6‐1 Model Using Short‐Term Hindcasts
Authors: Brient Florent , Roehrig Romain , Voldoire Aurore
Published: December 2018

The representation of stratocumulus by the atmospheric component of the Centre National de Recherches Météorologiques model version 6 (CNRM‐CM6‐1) is assessed. An Atmospheric Model Intercomparison Project‐type simulation is first used to document the main model errors, namely, a large lack of stratocumulus over the eastern part of tropical ocean basins. Short‐term hindcasts, following the Transpose‐Atmospheric Model Intercomparison Project framework, are then used to better assess the timescales associated with the cloud bias growth and to highlight the processes leading to them. These biases are shown to appear within only a few hours, independently of errors in the large‐scale circulation that set up within a few days. Key processes underlying the low‐cloud formation are thus mainly local and, to the first order, do not imply any feedback between the model physics and the large‐scale dynamics. As a consequence, short‐term hindcasts provide a relevant framework to investigate whether the low‐cloud underestimate is related to errors in the large‐scale state variables or to errors in the model parameterizations. Sensitivity tests highlight that the involved processes arise (1) mostly from misrepresentation of subgrid effects on cloud formation and (2) partly from biases in drying induced by cloud‐top entrainment mixing. Improvements in the representation of stratocumulus in the CNRM‐CM6‐1 model might thus be expected by including a more realistic subgrid‐scale temperature and moisture distribution, that would link convective and turbulence processes. Finally, this study confirms the potential of short‐term hindcasts, which provide a trustworthy framework to evaluate and develop climate model parameterizations.
A T-cell receptor escape channel allows broad T-cell response to CD1b and membrane phospholipids
Authors: Shahine Adam , Reinink Peter , Reijneveld Josephine F. , Gras Stephanie , Holzheimer Mira , Cheng Tan-Yun , Minnaard Adriaan J. , Altman John D. , Lenz Steffi , Prandi Jacques , Kubler-Kielb Joanna , Moody D. Branch , Rossjohn Jamie , Van Rhijn Ildiko
Published: December 2018

CD1 proteins are expressed on dendritic cells, where they display lipid antigens to T-cell receptors (TCRs). Here we describe T-cell autoreactivity towards ubiquitous human membrane phospholipids presented by CD1b. These T-cells discriminate between two major types of lipids, sphingolipids and phospholipids, but were broadly cross-reactive towards diverse phospholipids including phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine. The crystal structure of a representative TCR bound to CD1b-phosphatidylcholine provides a molecular mechanism for this promiscuous recognition. We observe a lateral escape channel in the TCR, which shunted phospholipid head groups sideways along the CD1b-TCR interface, without contacting the TCR. Instead the TCR recognition site involved the neck region phosphate that is common to all major self-phospholipids but absent in sphingolipids. Whereas prior studies have focused on foreign lipids or rare self-lipids, we define a new molecular mechanism of promiscuous recognition of common self-phospholipids including those that are known targets in human autoimmune disease.
Discoidin-domain receptor coordinates cell-matrix adhesion and collective polarity in migratory cardiopharyngeal progenitors
Authors: Bernadskaya Yelena Y. , Brahmbhatt Saahil , Gline Stephanie E. , Wang Wei , Christiaen Lionel
Published: December 2018

Integrated analyses of regulated effector genes, cellular processes, and extrinsic signals are required to understand how transcriptional networks coordinate fate specification and cell behavior during embryogenesis. Ciona cardiopharyngeal progenitors, the trunk ventral cells (TVCs), polarize as leader and trailer cells that migrate between the ventral epidermis and trunk endoderm. We show that the TVC-specific collagen-binding Discoidin-domain receptor (Ddr) cooperates with Integrin-β1 to promote cell-matrix adhesion. We find that endodermal cells secrete a collagen, Col9-a1, that is deposited in the basal epidermal matrix and promotes Ddr activation at the ventral membrane of migrating TVCs. A functional antagonism between Ddr/Intβ1-mediated cell-matrix adhesion and Vegfr signaling appears to modulate the position of cardiopharyngeal progenitors between the endoderm and epidermis. We show that Ddr promotes leader-trailer-polarized BMP-Smad signaling independently of its role in cell-matrix adhesion. We propose that dual functions of Ddr integrate transcriptional inputs to coordinate subcellular processes underlying collective polarity and migration.
Thromboembolism in Pregnancy: Gynecologists Perspective
Authors: Hari Anupama
Published: December 2018

Pregnancy is a thrombogenic condition in both antenatal and postpartum periods. Venous thromboembolism (VTE) is a common cause of morbidity, and the cause of maternal death in such situations is pulmonary embolism. There are several risk factors for thrombotic phenomena in pregnancy both acquired and hereditary. Accurate diagnosis of deep vein thrombosis (DVT) and its treatment are very important to prevent life-threatening pulmonary embolism. Among the diagnostic techniques, compression ultrasound is the mainstay for DVT diagnosis, whereas computed tomographic pulmonary angiography (CTPA) is for pulmonary embolism. Anticoagulants play a major role in therapy. They are used both in the active stage of thromboembolism and also in thromboprophylaxis in the postpartum period. Different types of heparins are available, which can be tailored to the individual requirements. During therapy they need monitoring to prevent hemorrhagic complications. Oral anticoagulants cannot be given in pregnancy as a general rule because of their teratogenicity, though they can be used in the postpartum period. Thrombolysis is can be taken up in selected cases in the acute situations. A very prolonged treatment of anticoagulants and compression stockings are needed in patients with past history of VTE. The most convenient drug regimen for prophylaxis is once-daily weight-adjusted low-molecular-weight heparin (LMWH). The goal of this article is to facilitate the recognition of thromboembolic disorders in pregnancy and different regimens in their management during antenatal, intrapartum, and postpartum periods. A few interesting and rare cases from the author’s experience are also presented at the end.
Cardiovascular Diseases of Genetic Etiology and Implications for the Pregnant Woman
Authors: Aggarwal Shagun
Published: December 2018

Pregnancy presents a unique hemodynamic challenge to women with cardiovascular disorders of genetic etiology. Many such women undergo decompensation during pregnancy or have acute cardiac events. In addition, there is a risk of transmission of the disease to the fetus, which warrants prenatal testing using invasive and noninvasive means. This article provides an overview of the management issues of these women during pregnancy.
Structural Heart Diseases during Pregnancy: Part 1—Valvular Heart Diseases
Authors: Patnaik Amar
Published: December 2018

It is estimated that about 3% pregnancies can have cardiac disease. There is wide variation in the spectrum of heart diseases. Pregnant women in India and other developing countries continue to show high prevalence of rheumatic heart disease (RHD). Pre-conception counseling based on a good echocardiographic evaluation is the most cost-effective method to prevent morbidity and mortality due to valvular heart disease. With advances in medical science, many with valvular heart disease are living to adulthood and undergoing successful pregnancy. Symptoms of a pregnant woman with a valvular disease depend on the altered hemodynamics of the specific valvular lesion in combination with the physiologic changes inherent to the pregnancy itself. A good echocardiographic evaluation of all pregnant women on their first visit to an obstetrician’s office is an effective strategy to prevent morbidity and mortality from valvular heart diseases. In general, the regurgitant lesions are well tolerated during pregnancy and labor. Asymptomatic but significant valve lesions can be decompensated by many factors. Severely stenosed mitral and, sometimes, aortic valve may have to be balloon-dilated by trained experts in midterm taking due care to avoid excess radiation. Valve surgery is rarely performed in absence of any other safer option. A multidisciplinary team approach is required to manage a pregnant woman with significant cardiac lesion with high-risk features and patients having mechanical valves that require continuous anticoagulation.
Anesthetic Management and Perioperative Events of Peripartum Cardiomyopathy during Cesarean Delivery a Series of Five Cases
Authors: Mellacheruvu Sree Rama , Chakravarthy Kousalya , Ahmed Khaliq
Published: December 2018

Peripartum cardiomyopathy (PPCM) is a rare idiopathic cardiomyopathy having an incidence of less than 0.1%. PPCM is associated with high morbidity and mortality rates ranging from 5 to 32%. In this review, the authors report a series of five PPCM cases. The case reports included pregnant women with PPCM, admitted in the hospital from October 1, 2017 to June 1, 2018 over a period of 9 months who required cesarean section. The authors aim to discuss the presentation, optimization, anesthetic management, and postoperative care of this rare condition. One of the cases was a booked case. The remaining four pregnant patients were referred in late pregnancy with features of congestive cardiac failure. One patient was in acute pulmonary edema, required intubation, and subsequently had cesarean section under general anesthesia. Four patients were managed with incremental epidural anesthesia. The need for proper preoperative optimization and intra- and postoperative management was discussed. The authors had one maternal mortality in our series. There was no neonatal mortality. Early diagnosis of PPCM, prompt treatment of heart failure, planning the delivery, and postpartum care can decrease maternal morbidity and mortality. Incremental epidural dosing can be used for cesarean section and has the advantage of stable hemodynamic status without the risks associated with general anesthesia.
Physiological Changes in Cardiovascular System during Normal Pregnancy: A Review
Authors: Taranikanti Madhuri
Published: December 2018

Pregnancy is a complex biological process associated with changes in physiologic functions of the body. Dramatic changes take place in the cardiovascular physiology leading to gradual adaptation of these changes by the body of the pregnant woman. Cardiac output increases during pregnancy to 30 to 50% above the prepregnant levels. The increase in cardiac output occurs due to increase in stroke volume initially during gestation and later by increase in heart rate. These changes in cardiac output are attributed to either neurohumoral factors such as estrogen and progesterone or placental factors. Maternal body position affects cardiac output with highest in kneel-chest and left lateral positions. Along with these changes, variations in heart rate, blood pressure, and blood volume are observed following a specific pattern of change during pregnancy. Hence, it is necessary to understand the cardiovascular changes during pregnancy to interpret, predict, and diagnose any cardiac disease efficiently.
Heart Failure in Pregnancy
Authors: Mahilmaran Asha
Published: December 2018

Cardiovascular mortality remains an important cause of maternal mortality other than the obstetric direct causes. Most cardiovascular deaths occur due to heart failure. Rheumatic heart diseases (RHD) account for more than two-thirds of heart diseases in pregnancy in low–middle income countries. Among RHD patients, 49% of patients with severe mitral stenosis, 31% with moderate mitral stenosis, and 23% with moderate to severe mitral regurgitation present with heart failure during pregnancy. In the U.K. registry, 25% of patients had heart failure due to cardiomyopathy. Congenital heart diseases such as atrial septal defect with severe pulmonary hypertension, significant atrioventricular valve regurgitation, peripartum, or dilated cardiomyopathy are less common causes of heart failure in pregnancy. Coronary artery diseases usually present as acute coronary syndromes during pregnancy, and heart failure as presentation is a rare occurrence. Preeclampsia and chronic hypertension can lead to increased vascular resistance, diastolic dysfunction, acute pulmonary edema, and acute heart failure. Two-thirds of heart diseases are diagnosed during the antepartum period itself. Preconception counseling, optimal medical therapy and avoidance of teratogens, and planning interventional or surgical therapies in patients with severe or moderate valvular diseases and congenital heart diseases will enable patients to enter the pregnancy well compensated. During pregnancy and postpartum, close surveillance and a multidisciplinary approach involving the obstetrician, cardiologist, physician, and anesthetist will lead to better maternal and fetal outcomes.
Maternal Outcome in Mitral Valve Disease with Pulmonary Hypertension: Two Case Reports
Authors: Alagandala Anuradha , Vaswani Daya , Bharadwaj Vuduthala , Chakravarthy Kousalya
Published: December 2018

Chronic rheumatic heart disease is still the leading cause of heart disease complicating pregnancy in the developing countries. The physiologic changes in pregnancy and stress induced by the increase in cardiac output can cause asymptomatic patients with mitral stenosis to decompensate, especially in the third trimester. Severity of mitral stenosis is reflected by the decrease in the valve area and increase in the right ventricular systolic pressures (RVSPs). Venous thromboembolism (VTE) is two to five times more common in the postpartum period, and the risk is high with cesarean delivery. Pulmonary embolism in pregnancy can cause severe maternal morbidity and mortality. We describe two cases of severe mitral stenosis complicating pregnancy with grossly elevated RVSP. The first case is the successful management of a second gravida, presenting with severe mitral stenosis with RVSP 80 mm Hg, and the second, a fatal case of a 26-year-old para 1, live 1, delivered by cesarean section, presenting with massive fatal pulmonary embolism on 13th postoperative day (POD) with RVSP 90 mm Hg. A multidisciplinary approach involving the cardiologist, obstetrician, and obstetric anesthesiologist is crucial for management of severe mitral stenosis complicating pregnancy, to decrease the maternal morbidity and mortality during peripartum period.
Association of Pregnancy-Related Factors and Cardiovascular Disease in the Long Term
Authors: Garre Indrani , Nemani Lalita , Nallagasu Raju
Published: December 2018

Aim To observe the association of pregnancy-related factors on the incidence of cardiovascular disease (CVD).

Introduction CVD is one of the leading causes of death in women. It really emphasizes the need for early recognition of cardiovascular risk in women. Heart disease in women poses a major challenge in that the first events are more likely to be fatal. Pregnancy itself predicts cardiovascular disease in later life and is a screening test for CVD.

Methods Total 136 female patients from the outpatient clinic, as well as patients of our hospital, were included in our retrospective single-center study. Along with demographic data and details of risk factors, the reproductive history of all patients such as age at first pregnancy, number of children, any hormonal therapy, and mode and place of delivery were noted. Pregnancy-related data, such as the history of hypertension, diabetes, abortion, pregnancy loss; preterm delivery; and the weight of the newborn were taken into consideration. We excluded unmarried and nulliparous women.

Results The study population comprised 136 female patients. There were 69 (50.74%) in group 1 (coronary artery disease [CAD] group) and 67 (49.36%) in group 2 (non-CAD group). Mean age of patients at enrollment was 53.2 ± 12.52 years. Twenty-seven (19.8%) patients fell under lost pregnancy or child category, and abortions and preterm delivery were faced in 26 (19.1%). Seventy-one (52.2%) patients attained menopause whereas hysterectomy was done in 35 (25.7%). The average age of hysterectomy was 38.37 ± 8.50 years, and that for menopause was 46.78 ± 5.04 years. During pregnancy, the history of hypertension was given only in 4 (3%), diabetes was in given none, and history of a low birth weight of the newborn was given in 3 (2.2%) women. The univariate analysis was done to see the statistical significance of mainly pregnancy factors on long-term cardiac outcomes along with risk factors. Generally, hypertension (p = 0.01) and diabetes (p = 0.01) had significance with cardiac outcomes. In spite of these, the history of a lost pregnancy/child and pregnancy complications both have shown near significance, that is, p = 0.06.

Conclusion Our study suggests an impact of pregnancy loss irrespective of the etiology on the future cardiac outcomes as along with predominant impact factors of hypertension and diabetes.
The Effect of Nicoumalone on Embryogenesis: A Retrospective Study
Authors: Nelavayi Chaitanya , Achukatla Kumar , Badhvel Bhanu , Gurram Sree , Velam Vanajakshamma , Pujari Latha
Published: December 2018

Objective To study the effect of nicoumalone on embryogenesis in women who have undergone mechanical heart valve replacement surgery.

Design It is a retrospective study done at Sri Venkateswara Institute of Medical Sciences (SVIMS), Tirupati.

Results Total 28 pregnancies were reported in 12 women with mechanical heart valve prostheses. Of these, 19 were live births, 9 abortions, and no stillbirths and miscarriages were noted in pregnant women. There were 11 hemorrhagic, 3 neurologic, 2 thromboembolic, and 1 stuck valve complications observed in mothers; and 2 low birth weights, 2 pneumonia, and 1 jaundice observed in the child.

Conclusion There were no abnormalities observed in children whose mothers were taking nicoumalone throughout pregnancy based on echo results and clinical examination.
Data-driven quantitative modeling of bacterial active nematics
Authors: Li He , Shi Xia-qing , Huang Mingji , Chen Xiao , Xiao Minfeng , Liu Chenli , Chaté Hugues , Zhang H. P.
Published: December 2018

Significance

Active nematics are nonequilibrium fluids consisting of elongated units driven at the individual scale. They spontaneously exhibit complex spatiotemporal dynamics and have attracted the attention of scientists from many disciplines. Here, we introduce an experimental system (made of filamentous bacteria) and a type of microscopic model for active nematics. Simultaneous measurements of orientation and velocity fields yield comprehensive experimental data that can be used to identify optimal values for all important parameters in the model. At these optimal parameters, the model quantitatively reproduces all experimentally measured features. This, in turn, reveals key processes governing active nematics. Our versatile approach successfully combines quantitative experiments and data-driven modeling; it can be used to study other dense active systems.
Conotoxin κM-RIIIJ, a tool targeting asymmetric heteromeric K
v
1 channels
Authors: Cordeiro Sönke , Finol-Urdaneta Rocio K. , Köpfer David , Markushina Anna , Song Jie , French Robert J. , Kopec Wojciech , de Groot Bert L. , Giacobassi Mario J. , Leavitt Lee S. , Raghuraman Shrinivasan , Teichert Russell W. , Olivera Baldomero M. , Terlau Heinrich
Published: December 2018

Significance

Most ion channels are multimeric (typically comprising 3–5 subunits). The subunits are encoded by homologous members of a gene family, generating an enormous set of possible heteromeric combinations. In this study, we provide evidence that the preferred target of conopeptide κM-RIIIJ is a heteromeric K
v
1 channel consisting of three K
v
1.2 subunits and one K
v
1.1 or K
v
1.6 subunit. We define the molecular interaction of κM-RIIIJ with these asymmetric K
v
1 channels and show that in dorsal root ganglia (DRG) neurons, different κM-RIIIJ concentrations can distinguish discrete subpopulations of neurons. Our results highlight the potential of natural products and venom components, such as conopeptides, to generally elucidate native physiological roles of specific heteromeric ion channel isoforms at the cellular, circuit, and systems level.
Constitutive Dicer1 phosphorylation accelerates metabolism and aging in vivo
Authors: Aryal Neeraj K. , Pant Vinod , Wasylishen Amanda R. , Parker-Thornburg Jan , Baseler Laura , El-Naggar Adel K. , Liu Bin , Kalia Awdhesh , Lozano Guillermina , Arur Swathi
Published: December 2018

Significance

Our discoveries provide evidence that posttranslational modification of Dicer1 drives aging, infertility, and metabolic disorder in mammals. These data suggest that phosphorylation of Dicer1 is a critical regulatory mechanism that dictates Dicer1 function and localization and provides a selective bias in miRNA processing. In addition, this work highlights the potential relevance of Dicer1 phosphorylation clinically, as
Dicer1
mutations and expression levels do not account for all cases of Dicer1-associated disease.
Non-invasive evaluation of coronary heart disease in patients with chronic kidney disease using photoplethysmography
Authors: Saritas Turgay , Greber Ruth , Venema Boudewijn , Puelles Victor G , Ernst Sabine , Blazek Vladimir , Floege Jürgen , Leonhardt Steffen , Schlieper Georg
Published: December 2018

Background

Chronic kidney disease (CKD) patients have an increased risk for coronary artery disease (CAD) and myocardial infarction. Therefore, there is a need to identify CKD patients at high risk of CAD. Coronary angiography, the gold standard for detecting CAD, carries a risk of serious adverse events.

Methods

Here, we assessed the validity of a novel non-invasive reflectance mode photoplethysmography (PPG) sensor for the evaluation of CAD in patients with advanced CKD. PPG signals were generated using green and infrared wavelengths and recorded from fingers of 98 patients. The detected signal has the shape of the pulse wave contour carrying information about the vascular system, that is, arterial stiffness. We studied four patient groups: (i) controls—patients without CKD or CAD; (ii) CKD alone; (iii) CAD alone (confirmed by coronary angiography); and (iv) CKD and CAD combined.

Results

With advancing age, we observed a steeper ascending signal during systole and greater signal decline during diastole (infrared wavelength: Slopes 4–6, P = 0.002, P = 0.003 and P = 0.014, respectively; green wavelength: Slopes 2–3, P = 0.006 and P = 0.005, respectively). Presence of CAD was associated with a slower signal decline during diastole in CKD patients compared with those without CAD (infrared wavelength: Slope 1, P = 0.012). CKD was associated with lower blood volume amplitude during each cardiac cycle compared with those without CKD (R-value, P = 0.022).

Conclusions

PPG signal analyses showed significant differences between our groups, and it may be a potentially useful tool for the detection of CAD in CKD patients.