bluuebunny/crossref_metadata_2025 huggingface dataset:
Peri-Operative Complications And Surgical Outcomes In Repeat Cesarean Section: A Retrospective Analysis
Authors: Yesmen Shahana , Tarannum Umme Rehnuma , Tabassum Sadia
Published: October 2024

Introduction: Repeat cesarean sections are becoming increasingly common due to the global rise in cesarean deliveries. While cesarean sections can be life-saving for both mother and baby, the risks associated with multiple procedures tend to increase. This study aims to evaluate these complications and outcomes to guide safer practices. Methods: This observational cross-sectional study was conducted Department of Obstetrics & Gynaecology, Chittagong Medical College & Hospital, from December 16-June’17. All the pregnant women who underwent repeat Caesarean section in Chittagong Medical College Hospital, Chittagong during the study period were considered as the study population. A total of 100 study subjects were selected by consecutive convenient sampling techniques. Data analysis was done by SPSS (Statistical Package for Social Sciences) 16. In all cases, p-value <05 was considered significant. Result: most repeat cesarean sections (70%) lasted about 1 hour, with 99% utilizing the Pfannenstiel incision. Adhesions were observed primarily with the bladder (8%), peritoneum (5%), and omentum (5%). A lower transverse uterine incision was used in 99% of cases, while 5% experienced scar dehiscence. Challenges during fetal delivery occurred in 5% of cases, and 3% had difficulty entering the peritoneal cavity. Placental abnormalities like placenta previa were noted in 6% of cases, and placental adherence (accreta or percreta) was found in 3%. Urinary bladder injuries occurred in 2% of cases. Blood loss was below 1 liter in 95% of surgeries, but 3% required significant transfusions. Elective tubal ligation was performed in 15% of cases, and some patients underwent additional procedures like Lynch surgeries or uterine artery ligations (3%). Conclusion: Notable complications are observed in repeat cesarean sections, including adhesions with the bladder, scar dehiscence, and challenges during fetal delivery. Additionally, placental abnormalities, such as placenta previa and abnormal adherence, highlight the complexities associated with repeat procedures. Most patients experienced minimal blood loss, with 95% losing less than 1 liter.
A Study On The Variations Of Structures Passing Through The Porta Hepatis Of Liver
Authors: Ningombam Tejrina , Thounaojam Kalpana , Karam Renuca , Gangmei Gaining , Remei Elizabeth
Published: October 2024

Background: The porta hepatis is a deep transverse fissure on the inferior surface of the liver, between the quadrate lobe anteriorly and the caudate process posteriorly. The major structures traversing in it are the portal vein, the hepatic artery and the hepatic duct. There are a lot of variations in the arrangement of structures passing through porta hepatis. Having knowledge of these variations becomes important to help in the existing knowledge so as to avoid complications during surgical and radiological interventions. The present study was carried out to study the arrangement and number of structures passing through porta hepatis and to report any variation thereof. Materials and methods: 40 formalin fixed adult cadaveric livers obtained from the Department of Anatomy, JNIMS, Imphal were studied. Porta hepatis was carefully dissected to observe a) arrangement, b) number of structures (artery, vein and duct) and c) the combination of the above structures. Results: There was consistent arrangement of the structures in porta hepatis with ducts, arteries and veins antero-posteriorly in all the livers studied. The most common finding had the combination of 1 vein, 2 arteries and 1 duct seen in 16 specimens (40%). Maximum number of arteries observed was 4 in 1 specimen (2.5%), vein was 2 in 3 specimens (7.5%) and duct was 2 in 7 specimens (17.5%). Various combinations of structures were observed and the porta hepatis with maximum number of structures passing through had the combination of 2 veins, 3 arteries and 2 ducts seen in 1 specimen (2.5%). Conclusion: The present study highlights the various combinations of the structures at the porta hepatis and will be therefore useful for the radiologists and surgeons dealing with this region.
Evaluation Of Lateral Root Resorption In Maxillary Teeth Among First Premolar Extraction Cases After Space Closure- A CBCT Study
Authors: Vargheese Dr. Shaji T , Unni Dr. Megha C , Jose Dr. Lijo , K C Dr. Suparna , P P Dr. Shafeequdheen
Published: October 2024

Background: Orthodontic treatment usually involves usage of light continuous forces but when heavy forces are used it leads to apical root resorption. External apical root resorption refers to reduction in root structure involving the apices. This resorption is of transient inflammatory type. 2D images are commonly used for diagnostic purposes in orthodontics but it cannot detect root resorption on lingual or buccal surfaces thus cannot measure the volume of root loss. Cone beam computed tomography which can provide 3D images was introduced in late 1990s. Images provided by CBCT are more more accurate than panoramic and periapical radiographs . Therefore in this study , CBCT is used to evaluate lateral root resorption in maxillary teeth after after space closure among first premolar extraction cases . Materials and Methods: CBCTs of 20 patients fulfilling inclusion and exclusion criteria were taken before the start of orthodontic treatment and after space closure. Post treatment root width was substracted from the pre treatment root width at three levels from CEJ (3mm,6mm,9mm). The normality test (Shapiro-Wilk Test) was performed to analyze the data, and the results were expressed as frequency with percentage and mean with standard deviation. Difference between means were assessed using paired t test for before and after the procedure. All the statistical analyses were carried out at a 5% level of significance, and results with a P value < 0.05 were considered statistically significant. Results: Considering all the three levels the least tooth resorption was observed in the case of central incisor (0.1750 ± 0.0444, p <0.001) and highest in the canine tooth (5.900± 0.0000, p <0.001) . Conclusion: When root resorption is detected, it is recommended to pause the treatment for about 6 months to allow for root repair. Intermittent forces, which provide rest periods between applications, are more tissuefriendly and can help reduce the risk of further resorption
Clinical Case Scenario: New Onset Refractory Status Epilepticus And Their Management.
Authors: Verma Dr. Durga
Published: October 2024

28 year old male Bank manager by profession caught with seizure , in-spite of taking multiple medication in different health care the symptom didn’t subside. Ultimately he landed to emergency were he started on multiple medication for seizure as the symptom was refractory and later diagnosed with New Onset Refractory Status Epilepticus (NORSE). The causative organism was considered to be Acinetobacter Baumanii on CSF examination. On prolonged sedative medication and mechanical ventilation he was diagnosed with Ventilatory associated pneumonia , the causative organism was found to be Klebsiella pneumoniae, Pseudomonas aeruginosa, Providencia infection for which he started on antibiotic therapy. In-spite of all the efforts even due to multiple medication and antibiotic therapy patient landed into septic shock
Evaluation Of Spirometric Parameters In Patients With Type 2 Diabetes Mellitus - A Cross-Sectional Study In A Tertiary Care Hospital In North East India
Authors: S Bhattacharjee , S Saha , D Chakraborty
Published: October 2024

Introduction: Diabetes mellitus is a common metabolic disorder that affects different organ systems in our body. Pulmonary complication of diabetes is not well characterized because of scarcity of data. Purpose of the present study was to evaluate the lung functions among the patients with Type2 DM. Materials and method: To evaluate the lung functions 85 type 2 diabetic patients were included in the study. Informed consent was obtained from the study participants. After taking a brief history, spirometry was performed among the recruited patients. The data were recorded in Microsoft excel and analyzed using SPSS software. Result: The quantitative data were expressed in terms of mean and standard deviation. Lung function parameters FVC, FEV1, and MVV were (2.05±0.66) Liters, (2.05±0.66) Liters and (52.22±18.17) L/min respectively. FEV1/FVC ratio was 73.74±13.36. FEV1 had a significant (p value: 0.002) negative correlation with duration of diabetes (r value: -0.330). Conclusion: The spirometric parameters FVC, FEV1 and MVV were found to be reduced among the study participants, whereas FEV1/FVC ratio was normal. These findings suggest presence of deterioration of lung functions among type 2 diabetic patients which is of restrictive type. Our study also showed that deterioration of lung function is more as the duration of disease increases. Therefore, the patients with type2 diabetes are needed to undergo pulmonary function testing periodically
"Optical Properties and Translucency of ImplantSupported PEEK Crowns: Spectrophotometric Evaluation"
Authors: Shah Dr. Praneti , Mahajan Dr. Namrta , Sharma Dr. Alok , Khetan Dr. Jitendra , Yadav Dr.Ritu
Published: October 2024

AIM- To evaluate the difference in optical properties and translucency parameters of implant supported PEEK crowns at different time intervals. MATERIAL AND METHODS: Optical properties and translucency parameters of implant supported PEEK crowns were assessed in 35 patients using spectrophotometer RESULT: Results revealed noticeable changes in translucency parameters and optical properties of implant supported PEEK crowns at 3 months. CONCLUSION- Our study on 35 patients on implant-supported PEEK crowns revealed that glazing improves surface roughness and opalescence, enhancing aesthetic appeal. Although, oral fluids containing intrinsic and extrinsic factors still adversely affect PEEK's color stability and surface quality
Health Workers Perception On The Key Drivers Of Maternal Mortality
Authors: Hassan Saidu Malgwi , Okoli Ernest Chinedu , Okoye Nelyn Akunna , Adindu Kelechi Nelson , Agbo Peter Kenechukwu
Published: October 2024

Maternal mortality remains a critical public health issue, particularly in low- and middle-income countries. Health workers play a pivotal role in addressing this challenge, offering insights into the key drivers of maternal deaths. This study explores the perceptions of healthcare workers on the systemic, socioeconomic, cultural, and healthcare-related factors contributing to maternal mortality. Health workers identify systemic barriers, including understaffing, lack of resources, inadequate training, and inefficient referral systems, as significant contributors. Cultural and religious influences also impact maternal care, with societal norms often discouraging women from seeking professional healthcare. Additionally, socioeconomic factors like poverty, illiteracy, and unemployment further exacerbate the problem, limiting access to quality maternal care. Health workers’ insights are crucial in designing effective interventions, emphasizing the need for improved training, better healthcare infrastructure, and community engagement to address cultural barriers. This study highlights the importance of empowering healthcare professionals to deliver high-quality maternal care, suggesting that systemic reforms, including enhanced emergency obstetric care and better access to medical supplies, are essential for reducing maternal mortality rates. Understanding these perspectives can inform policies and programs aimed at improving maternal health outcomes, particularly in resource-limited settings
The Subtle Signs Of Neonatal Grave’s Disease- ACase Report And Review
Authors: K Pooja , G Vidya , Kochar I.P.S , B Saroja , B Sakshi
Published: October 2024

A newborn male is born via caesarean section at 37 weeks of gestation to a 25-year-old primigravida mother. Mother was a known case of Grave’s disease (TSH receptor antibody positive) on Carbimazole with gestational diabetes mellitus on Insulin, her antenatal course was otherwise uneventful, with normal fetal heart rate monitoring and appropriate fetal growth. She was admitted with complaints of pain abdomen and decreased fetal movement. She was planned for emergency section and a live, healthy male baby was born with a birth weight of 2.962 kg, appropriate for gestation age with APGAR 8/9. Postnatal examination was negative for congenital anomalies and no systemic involvement was noticed. The baby was discharged on close follow-up. On day 7th of life, the baby was re-admitted for phototherapy. In this admission, the baby was noticed to have a resting tachycardia heart rate of 170-180/min, no murmur or abnormal heart sound was noticed on examination. The baby had no significant weight loss or history of feeding difficulties. In consideration of maternal grave disease, a further workup for the baby was planned, which revealed a Cord TSH (0.007microIU/ml) range (2.30-13.20) and free T4 1.52 ng/dl (Range 1.10-2.00). Further, the workup revealed TSH receptor antibody positive 23.76 IU/L range (less than 1.22), free T4 7.77 ng/dl (1.120-2.00), TSH less than 0.005 microIU/ml. However, As per the paediatric Endocrinologist's opinion, the baby was started on propranolol and propylthiouracil. The resting tachycardia resolved upon starting the drug. On subsequent follow-up, the baby had an improving thyroid profile
Gingival Hyperplasia - A Multifaceted Enigma
Authors: Bhattacharya Dr. Maumita , Bose Dr. Surajit , Sen Dr. Subhalakshmi , Dey Avinandan , Roy Bidushi , Bahal Aditi
Published: October 2024

Gingival hyperplasia or, gingival enlargement has become an increasing concern due to a number of factors prevalence whether it be an inflammatory enlargement or a drug induced enlargement; hyperplasia associated with conditions like pregnancy, puberty, vitamin C deficiency or systemic diseases like leukaemia, sarcoidosis and Wegener granulomatosis; whether it be a neoplasm addressed as “gingival tumours” or a false gingival hyperplasia. All these entities and conditions seriously impose a massive effect on the gingival tissue. Drug induced gingival overgrowth occurs due to adverse effects of drug reactions or adverse drug reaction (ADR), it occurs specifically in patients who are under the influence of immunosuppressives, calcium channel blockers, anticonvulsants, cyclosporine, phenytoin, etc. As the growth of the gingiva occurs patient complains of pain which affects many other functions like masticatory functions and also disfigures the condition of the gingiva. Among many people it is a cause of concern and other unwanted effects. Here we discuss a case that demonstrates the effect of amlodipine on gingival tissues.[3]
Revisiting Chloroquine In Malaria Treatment: A Pharmacological Perspective
Authors: Adamu Adamu Ahmed , Jimoh Abddulgafar O.
Published: October 2024

Malaria remains a global health concern, with artemisinin-based combination therapies (ACTs) serving as the gold standard for treatment. However, increasing reports of ACT resistance and treatment failure necessitate a reassessment of chloroquine, once the cornerstone of malaria management. This review explores the pharmacological arguments for and against the reintroduction of chloroquine, focusing on effectiveness, safety, pharmacoeconomic, patient compliance, availability, and acceptance. The objective is to determine whether the case against chloroquine is sufficient to discredit its use entirely or whether it merits reconsideration as an alternative therapy in regions where ACT resistance is on the rise
“Assessment Of Cardiac Autonomic Dysfunction In Children With Cerebral Palsy Using Heart Rate Variability”
Authors: R Dadegal Vineet , C Gayathri Devi , Y S Chinmayi , T N Satyaprabha
Published: October 2024

Background: Cardiac autonomic imbalance in children with CP might be due to primary brain insult, vary with different levels of Gross Motor Functional Classification System or may alter with multimodal therapies in various types of cerebral palsy (1,2) . It is important to understand and to create awareness that autonomic impairment in children with CP is in part due to sedentary lifestyle (3).HRV(Heart Rate Variability) in cerebral palsy is recognized as an important tool for monitoring cardiovascular health, in which autonomic imbalance is characterized by reduced HRV (i.e. regarded as increased cardiac sympathetic activity and decreased vagal modulation) (4,5) . Of the research that does exist, each study discusses only very few parameters of the autonomic nervous system, thus providing opportunities for further research and hence the need for the study. Materials and Methods: This is a cross-sectional case control study of 51 children with Cerebral Palsy (CP) and 51 normal children, conducted at District Early Intervention Centre (DEIC) in the Department of Paediatrics, Vani Vilas hospital. These 51 cases were assessed and classified based on their demographic features, etiology, type of CP, GMFCS scale and with the objectives of assessing the heart rate variability (HRV) in children with cerebral palsy and compare it with controls in both supine position and after a stress test, and also to correlate the obtained parameters with GMFCS level, type of CP using a systematically designed proforma. Results: Results of the study showed that of the children with CP studied, 62% were male children, and majority of were between 6-8 years of age (58%), and it was found that the most common etiology for CP in our study was due to perinatal asphyxia (43%), and 80% of the children had history of NICU admission. Of the 51 cerebral palsy children studied 72% were in GMFCS levels 3 and 4, regarding the topographical classification majority had spastic quadriplegia (58.8%) followed by spastic diplegia (15.7%). Study revealed that cerebral palsy children had significantly lower HRV, higher sympathetic activity, autonomic response deficit to stress test, and higher autonomic dysfunction when compared to normal children. Among cases, HRV was lowest with spastic quadriplegia and triplegic CP, in functional classification HRV was lowest among GMFCS 4 and 3. Conclusion: Cerebral palsy children had significantly higher sympathetic activity and less cardiac vagal modulation compared to normal children in supine position and there was existence of autonomic response deficit in cerebral palsy children after stress test, higher the motor impairment, higher was the sympathetic activity
Anaesthesiologists Awareness On Effect Of Anaesthetic Agents On Personnel And Environment
Authors: C Arunseth , M.P Sujatha
Published: October 2024

Background Global warming is one of the biggest issues we face in our day-to-day life. As an anaesthetist it our responsibility to know our contribution to this global issue and how to keep it in control. Anaesthetic agents also contribute to this issue of environmental pollution according to the recent literature. As anaesthetists we need to be aware of this effect and try to reduce the harmful effects by using alternative methods .The recent epidemic of COVID 19 has increased the production of hospital wastage by billions of tons, so we all should be aware of the consequence and should have the knowledge to minimise the waste production. Materials and Methods: In this study, a questionnaire of 20 questions was sent via email to consultant anaesthetists and anaesthesia post graduates of different medical colleges across India, after obtaining consent from the participants. These questions prepared on a google form. Results: Majority of study participants had less than 5 years of experience in anaesthesiology. Most of participants (70%) had excellent knowledge regarding effect of anaesthetic agent on personal and environment. There was no statistically significant difference found between gender, years of experience and Knowledge score. Conclusion: There was no statistically significant difference found between gender and Knowledge score. There was no statistically significant difference found between years of experience and Knowledge score.
New Onset Refractory Status Epilepticus Case And Their Management
Authors: Verma Dr. Durga
Published: October 2024

32 year old male laborer by profession caught with seizure , in-spite of taking multiple medication in different health care the symptom didn’t subside. Ultimately, he landed to emergency where he started on multiple medication for seizure as the symptom was refractory and later diagnosed with New Onset Refractory Status Epilepticus (NORSE).
Examination Of Pre-Testing Mistakes In A Newly Established Clinical Biochemistry Lab
Authors: . .
Published: October 2024

Background: The pre-analytical phase in laboratory diagnostics remains a significant source of errors, directly impacting patient care. This study aimed to investigate the prevalence and types of pre-analytical errors at a tertiary care hospital. Methods: A total of 5345 samples were evaluated over two months. Errors were categorized into types, and their distribution across various departments was assessed. Results: The overall error rate was 9.7%. Mismatched or wrong vials emerged as the most frequent error at 25%. Hemolysed samples accounted for 17.3%, and inadequate samples contributed to 16.3% of the errors. Significant variability in error rates was observed across departments, with Medicine and Surgery departments showing the highest frequencies at 23.1% and 21.2%, respectively. Conclusion: Our findings underscore the pressing need for targeted interventions in the pre-analytical phase, especially concerning sample collection and handling procedures. Department-specific strategies, ongoing training, and monitoring are crucial for minimizing errors and ensuring patient safety
Pulse Oximetry Derived Perfusion Index As A Predictor Of The Efficacy Of Rescue Analgesia After Major Abdominal Surgeries
Authors: Rukminiseshadri Kotlo , M.P Sujatha
Published: October 2024

Background: Perfusion index is an assessment of the pulsatile strength at a specific monitoring site and as such PI is an indirect and non-invasive measure of peripheral perfusion. The changes in sympathetic tone affect smooth muscle tone and can alter the perfusion, but are not affected by saturation and HR variability.so this study was conducted to assess the perfusion index and its effectiveness on requirement of rescue analgesia. Materials and Methods: A Prospective observational study was conducted among 30 who were undergoing major abdominal surgeries at R.L. Jalappa Hospital and Research Centre, Tamaka, Kolar. Sampling Method was Convenient sampling. Results This study was conducted among 30 patients. The mean age of study participants 32.1 + 12.4 years. Females were more compared to males. The mean height was 156.4 cm and the mean weight was 71.2kg. Pre analgesic vitals findings, the mean HR was 62.5/min, mean RR was 13.1/min, the mean spo2 was 98% and the MAP was 70 mmhg. Post analgesic vitals findings, the mean HR was 92.5/min, mean RR was 15.5/min, the mean spo2 was 97% and the MAP was 80 mmhg. There was a statiscally significant difference between pre analgesia and post analgesia perfusion index
Inhibition of fucosylation in human invasive ductal carcinoma reduces E‐selectin ligand expression, cell proliferation, and ERK1/2 and p38 MAPK activation
Authors: Carrascal Mylène A. , Silva Mariana , Ramalho José S. , Pen Cláudia , Martins Manuela , Pascoal Carlota , Amaral Constança , Serrano Isabel , Oliveira Maria José , Sackstein Robert , Videira Paula A.
Published: December 2017

Breast cancer tissue overexpresses fucosylated glycans, such as sialyl‐Lewis X/A (sLeX/A), and α‐1,3/4‐fucosyltransferases (FUTs) in relation to increased disease progression and metastasis. These glycans in tumor circulating cells mediate binding to vascular E‐selectin, initiating tumor extravasation. However, their role in breast carcinogenesis is still unknown. Here, we aimed to define the contribution of the fucosylated structures, including sLeX/A, to cell adhesion, cell signaling, and cell proliferation in invasive ductal carcinomas (IDC), the most frequent type of breast cancer. We first analyzed expression of E‐selectin ligands in IDC tissue and established primary cell cultures from the tissue. We observed strong reactivity with E‐selectin and anti‐sLeX/A antibodies in both IDC tissue and cell lines, and expression of α‐1,3/4 FUTs FUT4, FUT5, FUT6, FUT10, and FUT11. To further assess the role of fucosylation in IDC biology, we immortalized a primary IDC cell line with human telomerase reverse transcriptase to create the ‘CF1_T cell line’. Treatment with 2‐fluorofucose (2‐FF), a fucosylation inhibitor, completely abrogated its sLeX/A expression and dramatically reduced adherence of CF1_T cells to E‐selectin under hemodynamic flow conditions. In addition, 2‐FF‐treated CF1_T cells showed a reduced migratory ability, as well as decreased cell proliferation rate. Notably, 2‐FF treatment lowered the growth factor expression of CF1_T cells, prominently for FGF2, vascular endothelial growth factor, and transforming growth factor beta, and negatively affected activation of signal‐regulating protein kinases 1 and 2 and p38 mitogen‐activated protein kinase signaling pathways. These data indicate that fucosylation licenses several malignant features of IDC, such as cell adhesion, migration, proliferation, and growth factor expression, contributing to tumor progression.
Geophysical Characterization of Serpentinite Hosted Hydrogeology at the McLaughlin Natural Reserve, Coast Range Ophiolite
Authors: Ortiz Estefania , Tominaga Masako , Cardace Dawn , Schrenk Matthew O. , Hoehler Tori M. , Kubo Michael D. , Rucker Dale F.
Published: December 2017

Geophysical remote sensing both on land and at sea has emerged as a powerful approach to characterize in situ water‐rock interaction processes in time and space. We conducted 2‐D Electrical Resistivity Tomography (ERT) surveys to investigate in situ hydrogeological architecture within the Jurassic age tectonic mélange portion of the Coast Range Ophiolite Microbial Observatory (CROMO) during wet and dry seasons, where water‐rock interactive processes are thought to facilitate a subsurface biosphere. Integrating survey tracks traversing two previously drilled wells, QV1,1 and CSW1,1 at the CROMO site with wireline and core data, and the Serpentine Valley site, we successfully documented changes in hydrogeologic properties in the CROMO formation, i.e., lateral and vertical distribution of conductive zones and their temporal behavior that are dependent upon seasonal hydrology. Based on the core‐log‐ERT integration, we propose a hydrogeological architectural model, in which the formation is composed of three distinct aquifer systems: perched serpentinite aquifer without seasonal dependency (shallow system), well‐cemented serpentine confining beds with seasonal dependency (intermediate system), serpentinite aquifer (deep system), and the ultramafic basement that acts as a quasi‐aquiclude (below the deep system). The stunning contrast between the seasonality in the surface water availability and groundwater storativity in the formation allowed us to locate zones where serpentinite weathering and possibly deeper serpentinization processes might have taken place. We based our findings primarily on lithological composition and the distribution of the conductive formation, our work highlights the link between serpentinite weathering processes and possible sources of water in time and space.
Tephrostratigraphy and Provenance From IODP Expedition 352, Izu‐Bonin Arc: Tracing Tephra Sources and Volumes From the Oligocene to Recent
Authors: Kutterolf S. , Schindlbeck J. C. , Robertson A. H. F. , Avery A. , Baxter A. T. , Petronotis K. , Wang K.‐L.
Published: December 2017

Provenance studies of widely distributed tephras, integrated within a well‐defined temporal framework, are important to deduce systematic changes in the source, scale, distribution, and changes in regional explosive volcanism. Here, we establish a robust tephrochronostratigraphy for a total of 157 marine tephra layers collected during IODP Expedition 352. We infer at least three major phases of highly explosive volcanism during Oligocene to Pleistocene time. Provenance analysis based on glass composition assigns 56 of the tephras to a Japan source, including correlations with 12 major and widespread tephra layers resulting from individual eruptions in Kyushu, Central Japan, and North Japan between 115 ka and 3.5 Ma. The remaining 101 tephras are assigned to four source regions along the Izu‐Bonin arc. One, exclusively assigned to the Oligocene age, is proximal to the Bonin Ridge islands; two reflect eruptions within the volcanic front and back‐arc of the central Izu‐Bonin arc, and a fourth region corresponds to the Northern Izu‐Bonin arc source. First‐order volume estimates imply eruptive magnitudes ranging from 6.3 to 7.6 for Japan‐related eruptions and between 5.5 and 6.5 for IBM eruptions. Our results suggest tephras between 30 and 22 Ma reflect a subtly different Izu‐Bonin chemical signature compared to the recent arc. After a ∼9 Ma gap in eruption, tephra supply from the Izu‐Bonin arc predominated from 15 to 5 Ma, and finally a subequal mixture of tephra sources from the (palaeo)Honshu and Izu‐Bonin arcs occured within the last ∼5 Ma.
Microseismicity Linked to Gas Migration and Leakage on the Western Svalbard Shelf
Authors: Franek Peter , Plaza‐Faverola Andreia , Mienert Jürgen , Buenz Stefan , Ferré Bénédicte , Hubbard Alun
Published: December 2017

The continental margin off Prins Karls Forland, western Svalbard, is characterized by widespread natural gas seepage into the water column at and upslope of the gas hydrate stability zone. We deployed an ocean bottom seismometer integrated into the MASOX (Monitoring Arctic Seafloor‐Ocean Exchange) automated seabed observatory at the pinch‐out of this zone at 389 m water depth to investigate passive seismicity over a continuous 297 day period from 13 October 2010. An automated triggering algorithm was applied to detect over 220,000 short duration events (SDEs) defined as having a duration of less than 1 s. The analysis reveals two different types of SDEs, each with a distinctive characteristic seismic signature. We infer that the first type consists of vocal signals generated by moving mammals, likely finback whales. The second type corresponds to signals with a source within a few hundred meters of the seismometer, either due east or west, that vary on short (∼tens of days) and seasonal time scales. Based on evidence of prevalent seafloor seepage and subseafloor gas accumulations, we hypothesize that the second type of SDEs is related to subseafloor fluid migration and gas seepage. Furthermore, we postulate that the observed temporal variations in microseismicity are driven by transient fluid release and due to the dynamics of thermally forced, seasonal gas hydrate decomposition. Our analysis presents a novel technique for monitoring the duration, intensity, and periodicity of fluid migration and seepage at the seabed and can help elucidate the environmental controls on gas hydrate decomposition and release.
An Empirical Orthogonal Function Reanalysis of the Northern Polar External and Induced Magnetic Field During Solar Cycle 23
Authors: Shore R. M. , Freeman M. P. , Gjerloev J. W.
Published: December 2017

We apply the method of data‐interpolating empirical orthogonal functions (EOFs) to ground‐based magnetic vector data from the SuperMAG archive to produce a series of month length reanalyses of the surface external and induced magnetic field (SEIMF) in 110,000 km2 equal‐area bins over the entire northern polar region at 5 min cadence over solar cycle 23, from 1997.0 to 2009.0. Each EOF reanalysis also decomposes the measured SEIMF variation into a hierarchy of spatiotemporal patterns which are ordered by their contribution to the monthly magnetic field variance. We find that the leading EOF patterns can each be (subjectively) interpreted as well‐known SEIMF systems or their equivalent current systems. The relationship of the equivalent currents to the true current flow is not investigated. We track the leading SEIMF or equivalent current systems of similar type by intermonthly spatial correlation and apply graph theory to (objectively) group their appearance and relative importance throughout a solar cycle, revealing seasonal and solar cycle variation. In this way, we identify the spatiotemporal patterns that maximally contribute to SEIMF variability over a solar cycle. We propose this combination of EOF and graph theory as a powerful method for objectively defining and investigating the structure and variability of the SEIMF or their equivalent ionospheric currents for use in both geomagnetism and space weather applications. It is demonstrated here on solar cycle 23 but is extendable to any epoch with sufficient data coverage.
Differing Properties of Two Ion‐Scale Magnetopause Flux Ropes
Authors: Alm L. , Farrugia C. J. , Paulson K. W. , Argall M. R. , Torbert R. B. , Burch J. L. , Ergun R. E. , Russell C. T. , Strangeway R. J. , Khotyaintsev Y. V. , Lindqvist P.‐A. , Marklund G. T. , Giles B. L.
Published: December 2017

In this paper, we present results from the Magnetospheric Multiscale constellation encountering two ion‐scale, magnetopause flux ropes. The two flux ropes exhibit very different properties and internal structure. In the first flux rope, there are large differences in the currents observed by different satellites, indicating variations occurring over sub‐di spatial scales, and time scales on the order of the ion gyroperiod. In addition, there is intense wave activity and particle energization. The interface between the two flux ropes exhibits oblique whistler wave activity. In contrast, the second flux rope is mostly quiescent, exhibiting little activity throughout the encounter. Changes in the magnetic topology and field line connectivity suggest that we are observing flux rope coalescence.
Multiple Emplacement and Exhumation History of the Late Mesozoic Dayunshan‐Mufushan Batholith in Southeast China and Its Tectonic Significance: 2. Magnetic Fabrics and Gravity Survey
Authors: Ji Wenbin , Chen Yan , Chen Ke , Wei Wei , Faure Michel , Lin Wei
Published: December 2017

The Late Mesozoic magmatic province is a prominent feature of the South China Block (SCB). However, the tectonic regimes associated with the magmatism are still elusive. A combined anisotropy of magnetic susceptibility and gravity study has been carried out to determine the fabric patterns and shape at depth of the Dayunshan‐Mufushan composite batholith in the north‐central SCB. This is a companion paper to Part 1 that presented the structural and geochronological data of this batholith. The magnetic fabrics in the batholith interior predominantly reflect magma flow structures. Two distinct patterns of the magnetic lineations are defined, around NNE‐SSW and WNW‐ESE trends for the early‐stage and late‐stage intrusions of the batholith, respectively. The gravity survey reveals that the early‐stage intrusion has a main feeder zone located below its northern part, while several linear feeder zones trending NNE‐SSW are inferred for the late‐stage intrusion. Integrating all results, a two‐stage construction of the batholith with distinct tectonic regimes has been established. It is concluded that the early‐stage intrusion experienced a southward magma transport during its emplacement, partially assisted by far‐field compression from the north at ca. 150 Ma. Conversely, the emplacement and exhumation of the late‐stage intrusion was accommodated by a NW‐SE crustal stretching involving a lateral magma expansion above the multiple feeder zones (likely corresponding to extensional fractures) and ductile shearing during 132–95 Ma localized mainly along the Dayunshan detachment fault. Finally, we discuss the geodynamic linkage between the paleo‐Pacific subduction and the Late Mesozoic tectonomagmatism in the SCB.
Modeled Full‐Flight Aircraft Emissions Impacts on Air Quality and Their Sensitivity to Grid Resolution
Authors: Vennam L. P. , Vizuete W. , Talgo K. , Omary M. , Binkowski F. S. , Xing J. , Mathur R. , Arunachalam S.
Published: December 2017

Aviation is a unique anthropogenic source with four‐dimensional varying emissions, peaking at cruise altitudes (9–12 km). Aircraft emission budgets in the upper troposphere lower stratosphere region and their potential impacts on upper troposphere and surface air quality are not well understood. Our key objective is to use chemical transport models (with prescribed meteorology) to predict aircraft emissions impacts on the troposphere and surface air quality. We quantified the importance of including full‐flight intercontinental emissions and increased horizontal grid resolution. The full‐flight aviation emissions in the Northern Hemisphere contributed ~1.3% (mean, min–max: 0.46, 0.3–0.5 ppbv) and 0.2% (0.013, 0.004–0.02 μg/m3) of total O3 and PM2.5 concentrations at the surface, with Europe showing slightly higher impacts (1.9% (O3 0.69, 0.5–0.85 ppbv) and 0.5% (PM2.5 0.03, 0.01–0.05 μg/m3)) than North America (NA) and East Asia. We computed seasonal aviation‐attributable mass flux vertical profiles and aviation perturbations along isentropic surfaces to quantify the transport of cruise altitude emissions at the hemispheric scale. The comparison of coarse (108 × 108 km2) and fine (36 × 36 km2) grid resolutions in NA showed ~70 times and ~13 times higher aviation impacts for O3 and PM2.5 in coarser domain. These differences are mainly due to the inability of the coarse resolution simulation to capture nonlinearities in chemical processes near airport locations and other urban areas. Future global studies quantifying aircraft contributions should consider model resolution and perhaps use finer scales near major aviation source regions.
Mechanisms Governing Interannual Variability of Stratosphere‐to‐Troposphere Ozone Transport
Authors: Albers John R. , Perlwitz Judith , Butler Amy H. , Birner Thomas , Kiladis George N. , Lawrence Zachary D. , Manney Gloria L. , Langford Andrew O. , Dias Juliana
Published: December 2017

Factors governing the strength and frequency of stratospheric ozone intrusions over the Pacific‐North American region are considered for their role in modulating tropospheric ozone on interannual timescales. The strength of the association between two major modes of climate variability—the El Niño–Southern Oscillation (ENSO) and the Northern Annular Mode (NAM)—and the amount of ozone contained in stratospheric intrusions are tested in the context of two mechanisms that modulate stratosphere‐to‐troposphere transport (STT) of ozone: (StratVarO3) the winter season buildup of ozone abundances in the lowermost stratosphere (LMS) and (JetVar) Pacific jet and wave breaking variability during spring. In essence, StratVarO3 corresponds to variability in the amount of ozone per intrusion, while JetVar governs the frequency of intrusions. The resulting analysis, based on two different reanalysis products, suggests that StratVarO3 is more important than JetVar for driving interannual variations in STT of ozone over the Pacific‐North American region. In particular, the abundance of ozone in the LMS at the end of winter is shown to be a robust indicator of the amount of ozone that will be contained in stratospheric intrusions during the ensuing spring. Additionally, it is shown that the overall strength of the winter season stratospheric NAM is a useful predictor of ozone intrusion strength. The results also suggest a nuanced relationship between the phase of ENSO and STT of ozone. While ENSO‐related jet variability is associated with STT variability, it is wave breaking frequency rather than typical ENSO teleconnection patterns that is responsible for the ENSO‐STT relationship.
The Impact of Cross‐track Infrared Sounder (CrIS) Cloud‐Cleared Radiances on Hurricane Joaquin (2015) and Matthew (2016) Forecasts
Authors: Wang Pei , Li Jun , Li Zhenglong , Lim Agnes H. N. , Li Jinlong , Schmit Timothy J. , Goldberg Mitchell D.
Published: December 2017

Hyperspectral infrared (IR) sounders provide high vertical resolution atmospheric sounding information that can improve the forecast skill in numerical weather prediction. Commonly, only clear radiances are assimilated, because IR sounder observations are highly affected by clouds. A cloud‐clearing (CC) technique, which removes the cloud effects from an IR cloudy field of view (FOV) and derives the cloud‐cleared radiances (CCRs) or clear‐sky equivalent radiances, can be an alternative yet effective way to take advantage of the thermodynamic information from cloudy skies in data assimilation. This study develops a Visible Infrared Imaging Radiometer Suite (VIIRS)‐based CC method for deriving Cross‐track Infrared Sounder (CrIS) CCRs under partially cloudy conditions. Due to the lack of absorption bands on VIIRS, two important quality control steps are implemented in the CC process. Validation using VIIRS clear radiances indicates that the CC method can effectively obtain the CrIS CCRs for FOVs with partial cloud cover. To compare the impacts from assimilation of CrIS original radiances and CCRs, three experiments are carried out on two storm cases, Hurricane Joaquin (2015) and Hurricane Matthew (2016), using Gridpoint Statistical Interpolation assimilation system and Weather Research and Forecasting‐Advanced Research Version models. At the analysis time, more CrIS observations are assimilated when using CrIS CCRs than with CrIS original radiances. Comparing temperature, specific humidity, and U/V winds with radiosondes indicates that the data impacts are growing larger with longer time forecasts (beyond 72 h forecast). Hurricane track forecasts also show improvements from the assimilation of CrIS CCRs due to better weather system forecasts. The impacts of CCRs on intensity are basically neutral with mixed positive and negative results.
Control of Delta Avulsion by Downstream Sediment Sinks
Authors: Salter Gerard , Paola Chris , Voller Vaughan R.
Published: December 2017

Understanding how fluxes are partitioned at delta bifurcations is critical for predicting patterns of land loss and gain in deltas worldwide. Although the dynamics of river deltas are influenced from both upstream and downstream, previous studies of bifurcations have focused on upstream controls. Using a quasi‐1‐D bifurcation model, we show that flow switching in bifurcations is strongly influenced by downstream sediment sinks. We find that coupling between upstream and downstream feedbacks can lead to oscillations in water and sediment flux partitioning. The frequency and initial rate of growth/decay of the oscillations depend on both upstream and downstream conditions, with dimensionless bifurcate length and bypass fraction emerging as key downstream parameters. With a strong offshore sink, causing bypass in the bifurcate branches, we find that bifurcation dynamics become “frozen”; that is, the bifurcation settles on a permanent discharge ratio. In contrast, under depositional conditions, we identify three dynamical regimes: symmetric; soft avulsion, where both branches remain open but the dominant branch switches; and full avulsion. Finally, we show that differential subsidence alters these regimes, with the difference in average sediment supply to each branch exactly compensating for the difference in accommodation generation. Additionally, the model predicts that bifurcations with shorter branches are less asymmetric than bifurcations with longer branches, all else equal, providing a possible explanation for the difference between backwater length distributaries, which tend to be avulsive, and relatively stable mouth‐bar‐scale networks. We conclude that bifurcations are sensitive both quantitatively and qualitatively to downstream sinks.
Effect of Dynamically Recrystallized Grains on Rare Earth Texture in Magnesium Alloy Extruded at High Temperature
Authors: Li Rongguang , Fu Guangyan , Xu Zeren , Su Yong , Hao Yongsheng
Published: December 2017

This work investigates texture evolution in an Mg–3Gd–0.2Al alloy during extrusion and after annealing at 500 °C. It shows that the dynamically recrystallized (DRX) grains formed in grain boundaries and twins have different influence on texture evolution. After extrusion, the DRX grains that nucleated at grain boundaries have texture distributing from <20–21> || ED to <11–21> || ED, while these in twins do from <10–12> || ED to <11–22> || ED. After further annealing process, the <11–21> || ED component is strengthened and become the dominating texture component, which results in a strong rare earth (RE) texture. Thus, the RE texture is mainly attributed to the preferential nucleation at grain boundaries during extrusion and the privileged growth of the grains with <11–21> || ED orientation during annealing.
Enhanced Capacity and Rate Capability of Nitrogen/Oxygen Dual‐Doped Hard Carbon in Capacitive Potassium‐Ion Storage
Authors: Yang Jinlin , Ju Zhicheng , Jiang Yong , Xing Zheng , Xi Baojuan , Feng Jinkui , Xiong Shenglin
Published: December 2017

The intercalation of potassium ions into graphite is demonstrated to be feasible, while the electrochemical performance of potassium‐ion batteries (KIBs) remains unsatisfying. More effort is needed to improve the specific capacity while maintaining a superior rate capability. As an attempt, nitrogen/oxygen dual‐doped hierarchical porous hard carbon (NOHPHC) is introduced as the anode in KIBs by carbonizing and acidizing the NH2‐MIL‐101(Al) precursor. Specifically, the NOHPHC electrode delivers high reversible capacities of 365 and 118 mA h g−1 at 25 and 3000 mA g−1, respectively. The capacity retention reaches 69.5% at 1050 mA g−1 for 1100 cycles. The reasons for the enhanced electrochemical performance, such as the high capacity, good cycling stability, and superior rate capability, are analyzed qualitatively and quantitatively. Quantitative analysis reveals that mixed mechanisms, including capacitance and diffusion, account for the K‐ion storage, in which the capacitance plays a more important role. Specifically, the enhanced interlayer spacing (0.39 nm) enables the intercalation of large K ions, while the high specific surface area of ≈1030 m2 g−1 and the dual‐heteroatom doping (N and O) are conducive to the reversible adsorption of K ions.
Magnetically Guided Self‐Assembly and Coding of 3D Living Architectures
Authors: Tocchio Alessandro , Durmus Naside Gozde , Sridhar Kaushik , Mani Vigneshwaran , Coskun Bukre , El Assal Rami , Demirci Utkan
Published: December 2017

In nature, cells self‐assemble at the microscale into complex functional configurations. This mechanism is increasingly exploited to assemble biofidelic biological systems in vitro. However, precise coding of 3D multicellular living materials is challenging due to their architectural complexity and spatiotemporal heterogeneity. Therefore, there is an unmet need for an effective assembly method with deterministic control on the biomanufacturing of functional living systems, which can be used to model physiological and pathological behavior. Here, a universal system is presented for 3D assembly and coding of cells into complex living architectures. In this system, a gadolinium‐based nonionic paramagnetic agent is used in conjunction with magnetic fields to levitate and assemble cells. Thus, living materials are fabricated with controlled geometry and organization and imaged in situ in real time, preserving viability and functional properties. The developed method provides an innovative direction to monitor and guide the reconfigurability of living materials temporally and spatially in 3D, which can enable the study of transient biological mechanisms. This platform offers broad applications in numerous fields, such as 3D bioprinting and bottom‐up tissue engineering, as well as drug discovery, developmental biology, neuroscience, and cancer research.