bluuebunny/crossref_metadata_2025 huggingface dataset:
Caspar determines primordial germ cell identity in Drosophila melanogaster
Authors: Das Subhradip , Hegde Sushmitha , Wagh Neel , Sudhakaran Jyothish , Roy Adheena Elsa , Deshpande Girish , Ratnaparkhi Girish S
Published: June 2024

Repurposing of pleiotropic factors during execution of diverse cellular processes has emerged as a regulatory paradigm. Embryonic development in metazoans is controlled by maternal factors deposited in the egg during oogenesis. Here, we explore maternal role(s) of Caspar (Casp), the
Drosophila
orthologue of human Fas-associated factor-1 (FAF1) originally implicated in host-defense as a negative regulator of NF-κB signaling. Maternal loss of either Casp or it’s protein partner, Transitional endoplasmic reticulum 94 (TER94) leads to partial embryonic lethality correlated with aberrant centrosome behavior, cytoskeletal abnormalities, and defective gastrulation. Although ubiquitously distributed, both proteins are enriched in the primordial germ cells (PGCs), and in keeping with the centrosome problems, mutant embryos display a significant reduction in the PGC count. Moreover, the total number of pole buds is directly proportional to the level of Casp. Consistently, it’s ‘loss’ and ‘gain’ results in respective reduction and increase in the Oskar protein levels, the master determinant of PGC fate. To elucidate this regulatory loop, we analyzed several known components of mid-blastula transition and identify the translational repressor Smaug, a zygotic regulator of germ cell specification, as a potential critical target. We present a detailed structure-function analysis of Casp aimed at understanding its novel involvement during PGC development.
Investigating Best Practices in Academic Writing: Suggestions for Argumentative Essay Writing Instructions
Authors: SARR Bineta
Published: June 2024

This piece of writing highlights that in an argumentative essay, also known as a persuasive essay, the writer’s purpose is to persuade the audience to agree with his or her ideas about a controversial topic. As such, that essay needs to be based on logic and not on emotion, and must include an opposing viewpoint or counter argument, which gives credibility and strength to it. This paper aims at exploring the best practices in academic writing by making suggestions for argumentative essay writing instructions at both high school and university levels. This work is of particular relevance because both students and professionals need to know how to write. I have conducted this study by collecting some argumentative essays from participants of academic writing courses organized by the American Center of Dakar in Senegal. The research findings show that this analysis will help users enhance their writing skills, be proficient in academic exams and tests with a view to becoming autonomous learners and workers.
Hemolysis, Elevated Liver Enzymes and Low Platelet (HELLP) Syndrome: A Dreaded Complication of Pre-eclampsia in a Young Nigerian Woman
Authors: Elegbua Callistus Obinna , Afolayan Surajdeen Tunde , Doneh Harold Yiralee , Akpu Bernard B. , Ubanatu Promise Onyeka , Elegbua Angela Adaku , Ubi Wofai , Ovbiagele Oiseremen Samuel
Published: June 2024

HELLP Syndrome is a fatal rare pregnancy-related syndrome characterised by hemolysis, elevated liver enzymes and low platelet count; occurring in 0.5-0.9% of all pregnancies and in 10-20% of pregnancies with severe pre-eclampsia.
HELLP Syndrome is a complication of severe pre-eclampsia; seventy percent of the cases are developed during the antepartum period, mainly between the 27th and 37th gestational weeks. Thirty percent are diagnosed postpartum often within 48hrs post-delivery. It is a dreaded obstetric catastrophe that is associated with both maternal and perinatal morbidity and mortality such as maternal disseminated intravascular coagulopathy, thrombocytopenia, intracranial hemorrhage, eclampsia, paralysis, liver rupture, maternal collapse and death as well as utero-placental insufficiency, intrauterine fetal death and stillbirth.
This obstetric complication is commonly diagnosed in pregnant women with poorly controlled pre-eclampsia, diabetes mellitus, renal disease and those who are not compliant with routine antenatal clinic visits thus, periconceptional care, adequate management of medical conditions of pregnancy and strict compliance to antenatal care services play vital roles in the prevention of HELLP Syndrome.
This case report presents the timely diagnosis and prompt management of a 35-year-old gravida 2 para 1 woman diagnosed with HELLP syndrome at 32weeks gestational age at the obstetrics and gynecology department in Nigerian Navy Reference Hospital Calabar, Nigeria.
Effect of Mid-Season Moisture Stress on Fatty Acid Composition of Groundnut (Arachis hypogaea L.) Genotypes
Authors: Priya K. Vishnu , Latha P. , Kumari S. Ratna , Kumar P. Ratna , Srividhya A.
Published: June 2024

A field experiment was conducted at Regional Agricultural Research Station, Tirupati, Acharya N.G. Ranga Agricultural University during rabi, 2022 and 2023 to study the effect of mid-season moisture stress on fatty acid composition of groundnut genotypes. The experiment was carried out in randomized block design (RBD) with factorial concept with two main treatments i.e., control and mid-season moisture stress (40-80 DAS) and 12 sub treatments i.e., two check varieties and ten contrasting groundnut genotypes sown in three replications. The study revealed that during rabi, 2022 and 2023 the genotype, TCGS 2326 recorded highest palmitic acid (12.67 and 12.99%) which was on par with K9 (11.96%) and TCGS 1792 (12.56%) during 2022 and 2023. Whereas, lowest palmitic acid was recorded by TCGS 2024 (9.51 and 10.00%). During rabi, 2022 highest stearic acid was recorded by TCGS 1792 (3.19%) which was at par with TCGS 2326 (3.14%) and during 2023, TCGS 2326 (3.34%) recorded highest stearic acid which was on par with TCGS 1792 (3.16%) whereas, lowest stearic acid was recorded by TCGS 2024 (2.47%) and TCGS 1785 (2.47%) during 2022 and 2023. Highest oleic acid was recorded by TCGS 1792 (53.02 and 52.67%) which was on par with TCGS 2333 (52.63 and 41.80%) and lowest oleic acid was recorded by TCGS 1785 (40.05 and 40.01%). Highest linoleic acid was recorded by TCGS 2024 (37.89%) and K6 (37.12%) whereas, lowest linoleic acid composition was recorded by TCGS 1792 (20.17%) and TCGS 2326 (20.13%) during 2022 and 2023.
Assessment of the Genotype × Environment Interaction in Groundnut (Arachis hypogaea L.) Genotypes for Yield and Its Contributing Traits under Different Dates of Sowing
Authors: Kumar Sunil , Sahi Vaidurya Pratap , Singh Anoj Kumar , Choudhary Shivani
Published: June 2024

The forty-five genotypes of groundnut were evaluated at Field Experimentation Centre of the Department of Genetics and Plant Breeding, Naini Agricultural Institute, SHUATS, Prayagraj (U.P.) during kharif, seasons of 2021-22 and 2022-23 in four artificially created environments by four different dates of sowing considered as E-I, E-II, E-III & E-IV. The present experiment was carried out in Randomized Block Design with three replications and involved recording observations on 17 yield and its contributing characters. Identifying stable-performing genotypes in the changing environmental scenario is of paramount importance in modern breeding materials. Crop improvement programme mostly depend on the identification of superior and stable genotypes. Mean sum of squares due to environment were found to be substantially distinct for all the traits and the mean sum of square due to genotype were found to be significant for all the characters. The regression coefficients (bi) of the genotypes ranged from -3.40 to 2.52 and the deviation from regression (S2di) ranged from -1.01 to 1.56. Stability parameters of various traits revealed that GJG-18, RG-574 and RG-559-3 pod yield per plant and RS-1 oil content showed high mean performance and regression coefficient close to unity and non-significant deviation from regression stable under overall environments. Thus indicating the importance of non-linear components in determining interaction of the genotypes with environments in the present study according to the Eberhart and Russell (1966) model.
Application of Machine Learning Techniques Models for Forecasting of Redgram Prices of Andhra Pradesh, India
Authors: Swarnalatha P. , Rao V. Srinivasa , Reddy G. Raghunadha , Rathod Santosha , Ramesh D. , Devi K. Uma
Published: June 2024

Recent advancements in Machine Learning (ML) had proven highly effective in modeling time series data, consistently outperforming traditional time series models in forecasting accuracy according to empirical studies. However, the application of ML techniques in forecasting agricultural commodity prices in India was remains scarce, despite their demonstrated success in other domains. The present study endeavours to investigate the efficiency of various machine learning (ML) algorithms, including Artificial Neural Network (ANN), Support Vector Regression (SVR) and Random Forest (RF) models, alongside traditional linear time series models such as SARIMA and GARCH models in forecasting of the monthly price series of redgram in Andhra Pradesh, India. The findings of this study indicated that the Random Forest (RF) model exhibited superior performance compared to other machine learning techniques and univariate time series models in forecasting redgram monthly prices in Andhra Pradesh. However, the forecasting accuracies of alternative techniques, including Support Vector Regression (SVR), Artificial Neural Network (ANN), GARCH, and SARIMA models, fell short of expectations. In this research, the superiority of various models was substantiated through accuracy metrics such as Mean Squared Error (MSE) and Root Mean Squared Error (RMSE). Additionally, the Diebold-Mariano test is conducted to assess significant differences in predictive accuracy among the models. The DM test also concluded that the RF model outperformed than the other models under consideration.
ILI-Related School Dismissal Monitoring System: An Overview and Assessment
Authors: Kann Laura , Kinchen Steve , Modzelski Bill , Sullivan Madeline , Carr Dana , Zaza Stephanie , Graffunder Corinne , Cetron Marty
Published: June 2012

Objective: This report provides an overview and assessment of the School Dismissal Monitoring System (SDMS) that was developed by the Centers for Disease Control and Prevention (CDC) and the US Department of Education (ED) to monitor influenza-like illness (ILI)-related school dismissals during the 2009-2010 school year in the United States.

Methods: SDMS was developed with considerable consultation with CDC's and ED's partners. Further, each state appointed a single school dismissal monitoring contact, even if that state also had its own school-dismissal monitoring system in place. The SDMS received data from three sources: (1) direct reports submitted through CDC's Web site, (2) state monitoring systems, and (3) media scans and online searches. All cases identified through any of the three data sources were verified.

Results: Between August 3, 2009, and December 18, 2009, a total of 812 dismissal events (ie, a single school dismissal or dismissal of all schools in a district) were reported in the United States. These dismissal events had an impact on 1947 schools, approximately 623 616 students, and 40 521 teachers.

Conclusions: The SDMS yielded real-time, national summary data that were used widely throughout the US government for situational awareness to assess the impact of CDC guidance and community mitigation efforts and to inform the development of guidance, resources, and tools for schools.

(Disaster Med Public Health Preparedness. 2012;6:104-112)
Prevention of Novel Influenza Infection in Newborns in Hospital Settings: Considerations and Strategies During the 2009 H1N1 Pandemic
Authors: Zapata Lauren B. , Kendrick Juliette S. , Jamieson Denise J. , MacFarlane Kitty , Shealy Katherine , Barfield Wanda D.
Published: June 2012

During the 2009 influenza A (H1N1) pandemic, many pregnant women experienced severe illness and some gave birth while ill with suspected or confirmed pandemic (H1N1) 2009 influenza. Because of concerns about possible transmission of this novel virus to immunologically naïve newborns, and the absence of definitive studies regarding this risk, the Centers for Disease Control and Prevention (CDC) reviewed relevant literature to understand the potential burden of disease and routes of transmission affecting newborns. This report describes the issues considered during the 2009 H1N1 pandemic as CDC developed guidance to protect newborns in hospital settings. Also presented is a framework of protection efforts to prevent novel influenza infection in fetuses/newborns before birth and in hospital settings. Although developed specifically for the pandemic, the framework may be useful during future novel influenza outbreaks.

(Disaster Med Public Health Preparedness. 2012;6:97-103)
Increasing Out-of-Hospital Regional Surge Capacity for H1N1 2009 Influenza A Through Existing Community Pediatrician Offices: A Qualitative Description of Quality Improvement Strategies
Authors: Cruz Andrea T. , Tittle Kay O. , Smith Elizabeth R. , Sirbaugh Paul E.
Published: June 2012

Objective: To describe initiatives undertaken by a network of community pediatricians to increase a city's surge capacity for patients presenting with influenza-like illnesses during the 2009 H1N1 influenza A pandemic.

Methods: This was a descriptive quality improvement project detailing the measures employed by a network of private practice community pediatricians in Houston, Texas, caring for both insured and uninsured children.

Results: Four categories of interventions were used: enhanced communication, increasing community pediatrician presence, vaccine distribution, and targeted viral diagnosis and antiviral utilization. Promoting communication between clinicians, families, and an affiliated local tertiary care children's hospital allowed for the efficient coordination of resources as well as a unified and consistent message. Increasing access of families to their primary medical home by employing additional clinicians, extending office hours, and locating additional space served to decrease the number of children with low-acuity illness seen in the local emergency centers. Vaccine distribution was enhanced by effective communication between clinicians and families. Finally, targeted antiviral testing and adherence to national recommendations on antiviral utilization enabled judicious utilization of a limited supply of antiviral medications.

Conclusions: Effective communication and improved access to health care enabled children within the network with influenza-like illnesses to continue to be cared for in their medical home. The measures used in response to novel influenza virus outbreaks can be adapted for other situations requiring increased community surge capacity.

(Disaster Med Public Health Preparedness 2012;6:113-116)
Triage of Mechanical Ventilation for Pediatric Patients During a Pandemic
Authors: Kim Kristin M. , Cinti Sandro , Gay Steven , Goold Susan , Barnosky Andrew , Lozon Marie
Published: June 2012

Objective: The novel H1N1 influenza pandemic renewed the concern that during a severe pandemic illness, critical care and mechanical ventilation resources will be inadequate to meet the needs of patients. Several published protocols address the need to triage patients for access to ventilator resources. However, to our knowledge, none of these has addressed the pediatric populations.

Methods: We used a systematic review of the pediatric critical care literature to evaluate pediatric critical care prognosis and multisystem organ failure scoring systems. We used multiple search engines, including MEDLINE and EMBASE, using a search for terms and key words including including multiple organ failure, multiple organ dysfunction, PELOD, PRISM III, pediatric risk of mortality score, pediatric logistic organ dysfunction, pediatric index of mortality pediatric multiple organ dysfunction score, “child+multiple organ failure + scoring system. ” Searches were conducted in the period January 2010-February 2010.

Results: Of the 69 papers reviewed, 22 were used. Five independently derived scoring systems were evaluated for use in a respiratory pandemic ventilator triage protocol. The Pediatric Logistic Organ Dysfunction (PELOD) scoring system was the most appropriate for use in such a triage protocol.

Conclusions: We present a pediatric-specific ventilator triage protocol using the PELOD scoring system to complement the NY State adult triage protocol. Further evaluation of pediatric scoring systems is imperative to ensure appropriate triage of pediatric patients.

(Disaster Med Public Health Preparedness. 2012;6:131–137)
Citizen Preparedness for Disasters: Are Current Assumptions Valid?
Authors: Uscher-Pines Lori , Chandra Anita , Acosta Joie , Kellermann Arthur
Published: June 2012

US government programs and communications regarding citizen preparedness for disasters rest on several untested, and therefore unverified, assumptions. We explore the assumptions related to citizen preparedness promotion and argue that in spite of extensive messaging about the importance of citizen preparedness and countless household surveys purporting to track the preparedness activities of individuals and households, the role individual Americans are being asked to play is largely based on conventional wisdom. Recommendations for conceptualizing and measuring citizen preparedness are discussed.

(Disaster Med Public Health Preparedness. 2012;6:170–173)
Mapping US Pediatric Hospitals and Subspecialty Critical Care for Public Health Preparedness and Disaster Response, 2008
Authors: Brantley Mary D. , Lu Hua , Barfield Wanda D. , Holt James B. , Williams Alcia
Published: June 2012

Objective: The objective is to describe by geographic proximity the extent to which the US pediatric population (aged 0-17 years) has access to pediatric and other specialized critical care facilities, and to highlight regional differences in population and critical resource distribution for preparedness planning and utilization during a mass public health disaster.

Methods: The analysis focused on pediatric hospitals and pediatric and general medical/surgical hospitals with specialized pediatric critical care capabilities, including pediatric intensive care units (PICU), pediatric cardiac ICUs (PCICU), level I and II trauma and pediatric trauma centers, and general and pediatric burn centers. The proximity analysis uses a geographic information system overlay function: spatial buffers or zones of a defined radius are superimposed on a dasymetric map of the pediatric population. By comparing the population living within the zones to the total population, the proportion of children with access to each type of specialized unit can be estimated. The project was conducted in three steps: preparation of the geospatial layer of the pediatric population using dasymetric mapping methods; preparation of the geospatial layer for each resource zone including the identification, verification, and location of hospital facilities with the target resources; and proximity analysis of the pediatric population within these zones.

Results: Nationally, 63.7% of the pediatric population lives within 50 miles of a pediatric hospital; 81.5% lives within 50 miles of a hospital with a PICU; 76.1% lives within 50 miles of a hospital with a PCICU; 80.2% lives within 50 miles of a level I or II trauma center; and 70.8% lives within 50 miles of a burn center. However, state-specific proportions vary from less than 10% to virtually 100%. Restricting the burn and trauma centers to pediatric units only decreases the national proportion to 26.3% for pediatric burn centers and 53.1% for pediatric trauma centers.

Conclusions: This geospatial analysis describes the current state of pediatric critical care hospital resources and provides a visual and analytic overview of existing gaps in local pediatric hospital coverage. It also highlights the use of dasymetric mapping as a tool for public health preparedness planning.

(Disaster Med Public Health Preparedness. 2012;6:117–125)
Survey of Emergency Management Professionals to Assess Ideal Characteristics of a Photographic-Based Family Reunification Tool
Authors: Chung Sarita , Monteiro Stephen , Ziniel Sonja I. , Kalish Leslie A. , Klaman Paula , Shannon Michael
Published: June 2012

Objective: A reunification tool that captures images of children at the time of the disaster would enable parents to locate their missing children, particularly if the children are unable to communicate their identity. This study assessed the ideal features and parameters of a photographic-based reunification tool.

Methods: A convenience sample of federal, state, and hospital-based emergency management professionals were surveyed to elicit their preferences regarding an image-based reunification algorithm, to assess the parents' level of difficulty in viewing images with facial trauma, and to determine the minimum percentage of successful reunifications needed to justify adoption of a reunification tool.

Results: Of 322 emergency management professionals surveyed, 129 (40%) responded. Only 18% favored a photographic-based tool that would display images in which only the categories of age, gender, and facial features (eye, hair, and skin color) would exactly match the parent's description of the child. However, 72% preferred a broader, less-rigid system in which the images displayed would match all or most features in the parents’ description of the missing child, allowing parents to view more of the image database. Most (85%) preferred a tool showing unedited images of living children, allowing parents to view facial trauma. However, more respondents reported that parents would find viewing unedited images with facial trauma somewhat or very difficult emotionally compared with edited images for both living (77% vs 20%, P <. 001) and deceased children (91% vs 70%, P <. 001.) In a disaster involving 1000 children, a tool that reunites a minimum of 10% of families would be adopted by over 50% of the participants. Participants were willing to accept a lower percentage of reunifications in a disaster involving 1000 children compared with disasters involving 10 (P <. 001) or 100 children. (P <. 001).

Conclusions: Emergency management professionals identified desirable characteristics of a photographic-based reunification tool, including an algorithm displaying unedited photographs of missing children that loosely matches the parents' description, acknowledging the parents' emotional difficulty in viewing photographs with facial trauma. Participants were also willing to accept a lower percentage of successful reunifications as the scale of the disaster size increased.

(Disaster Med Public Health Preparedness. 2012;6:156–162)
Aqueous‐Phase Sonogashira Alkynylation to Synthesize 5‐Substituted Pyrimidine and 8‐Substituted Purine Nucleosides
Authors: Cho Joon Hyung , Shaughnessy Kevin H.
Published: June 2012

In this unit, an efficient method for the synthesis of alkyne‐modified nucleosides in an aqueous solvent system is described. The method allows direct palladium‐catalyzed alkynylation of readily available unprotected 8‐bromo‐2′‐deoxyguanosine (8‐BrdG), 8‐bromo‐2′‐deoxyadenosene (8‐BrdA), 8‐bromoadenosine (8‐BrA), and 5‐iodo‐2′‐deoxyuridine (5‐IdU) precursors. The optimal catalyst is derived from palladium acetate, tri‐(2,4‐dimethyl‐5‐sulfonatophenyl)phosphane (TXPTS), and CuI. Curr. Protoc. Nucleic Acid Chem. 49:1.27.1‐1.27.10. © 2012 by John Wiley & Sons, Inc.
Children's Implanted False Memories and Additional Script Knowledge
Authors: Otgaar Henry , Smeets Tom , Peters Maarten
Published: June 2012

The present study examined whether repeatedly providing additional script knowledge of an event would boost the development of children's implanted false memories. Seventy‐two 7‐ to 9‐year‐old children listened to a true narrative about their first day at school and a false narrative describing that they went to a burns centre when they were four years old. Children were randomly allocated to one of three groups: one group without additional script knowledge and two groups that received a video about the two events to promote additional event‐related script knowledge of which one group had to view the video repeatedly (i.e. once a day). Across two interviews, children were encouraged to tell everything they remembered about the events. Results showed that at the second interview, children who were presented with the additional script knowledge were more likely to develop a false memory than the children who did not receive additional script knowledge. Copyright © 2012 John Wiley & Sons, Ltd.
Adaptive iterative learning control of discrete‐time varying systems with unknown control direction
Authors: Yan Weili , Sun Mingxuan
Published: June 2012

Without using Nussbaum gain, a novel method is presented to solve the unknown control direction problem for discrete‐time systems. The underlying idea is to fully exploit the convergence property of parameter estimates in well‐known adaptive algorithms. By incorporating two modifications into the control and the parameter update laws, respectively, we present an adaptive iterative learning control scheme for discrete‐time varying systems without the prior knowledge of the sign of control gain. It is shown that the proposed adaptive iterative learning control can achieve perfect tracking over the finite time interval while all the closed‐loop signals remain bounded. An illustrative example is presented to verify effectiveness of the proposed scheme. Copyright © 2012 John Wiley & Sons, Ltd.
Emission Color Trajectory and White Electroluminescence Through Supramolecular Control of Energy Transfer and Exciplex Formation in Binary Blends of Conjugated Polyrotaxanes
Authors: Brovelli Sergio , Sforazzini Giuseppe , Serri Michele , Winroth Gustaf , Suzuki Kosuke , Meinardi Francesco , Anderson Harry L. , Cacialli Franco
Published: June 2012

White electroluminescence and fine‐tuning of the emission color from binary blends of a blue‐emitting polymer and a green/yellow‐emitting threaded molecular wire consisting of a conjugated polymer supramolecularly encapsulated by functionalized cyclodextrins are demonstrated. Encapsulation controls the minimum intermolecular distance on the nanoscale, resulting in suppressed energy‐transfer between the blend constituents and reduced formation of interchain charge‐transfer complexes. The use of a green‐emitting polyrotaxane significantly improves the electrical properties with respect to blends of a blue electroluminescent polyrotaxane and leads to a significant reduction in the turn‐on voltage required for achieving white electroluminescence (VON = 3 V), with only 20% by weight of the encapsulated material.
Rapid Hydrogenation of Aromatic Nitro Compounds in Supercritical Carbon Dioxide: Mechanistic Implications via Experimental and Theoretical Investigations
Authors: Chatterjee Maya , Chatterjee Abhijit , Kawanami Hajime , Ishizaka Takayuki , Suzuki Toshishige , Suzuki Akira
Published: June 2012

An exceptionally rapid hydrogenation of nitrobenzene to aniline [TOF=252,000 h−1] over palladium containing MCM‐41 (Pd/MCM‐41) with excellent yield of >99% can be achieved in supercritical carbon dioxide at 50 °C and a hydrogen pressure of 2.5 MPa. It has been observed that this promising method preferred a single phase between liquid substrate and carbon dioxide‐hydrogen system. The ascendancy of the supercritical carbon dioxide medium is established in comparison with the conventional organic solvent and solvent‐less conditions. Changes in the reaction parameters such as carbon dioxide and hydrogen pressure, temperature and the reaction time do not affect the selectivity. A combined experimental and theoretical study has elucidated the mechanism under the studied reaction condition because experimental observations revealed a direct conversion of nitrobenzene to aniline. However, density functional theory (DFT) calculation shows that the direct conversion is energetically unfavourable; hence, a stepwise mechanism has been proposed. Theoretical predictions and experimental observations suggested that the rate‐limiting step of nitrobenzene conversion is different from that of the liquid phase hydrogenation. This catalytic process can also be successfully extended to the hydrogenation of other aromatic nitro compounds with different substituents. Easy separation of the liquid product from catalyst and the use of an environmentally friendly solvent make this procedure a viable and an attractive green chemical process.
Catalytic Asymmetric Synthesis of 2‐Alkyleneoxetanes through [2+2] Annulation of Allenoates with Trifluoromethyl Ketones
Authors: Zhao Qian‐Yi , Huang Long , Wei Yin , Shi Min
Published: June 2012

The first example of a β‐isocupreidine (β‐ICD)‐catalyzed highly enantioselective [2+2] annulation of allenoates with trifluoromethyl ketones has been disclosed, allowing the synthesis of optically active 2‐alkyleneoxetanes in moderate to good yields along with good to high enantioselectivities and high diastereoselectivities. Further transformations of the cycloadducts have been also disclosed to afford biologically interesting 6‐trifluoromethyl‐5,6‐dihydropyran‐2‐ones and trifluoromethyl β‐keto acids in good yields.
Global optimization of multicomponent distillation configurations: 1. Need for a reliable global optimization algorithm
Authors: Nallasivam Ulaganathan , Shah Vishesh H. , Shenvi Anirudh A. , Tawarmalani Mohit , Agrawal Rakesh
Published: June 2012

Nonazeotropic multicomponent mixtures are often separated into products by distillation configurations containing multiple distillation columns. One method of calculating the minimum vapor duty of a configuration is to sequentially calculate the minimum vapor duty of each mixture as it is split into two streams within a given column starting from the feed column. The other method simultaneously manipulates all the splits to yield the overall minimum vapor duty of the entire configuration. Of these two methods, the sequential minimization is attractive as it can be analytically solved. However, through extensive computations, we find that the sequential minimization method is not a valid substitute for the simultaneous minimization method. As the number of components in the feed increases, the fraction of the basic configurations for which sequential method yields a reasonable estimate decreases rapidly, thereby emphasizing the need for a more robust and reliable global optimization algorithm. © 2012 American Institute of Chemical Engineers AIChE J, 59: 971–981, 2013
Technical note: The use of geographical information systems software for the spatial analysis of bone microstructure
Authors: Rose David C. , Agnew Amanda M. , Gocha Timothy P. , Stout Sam D. , Field Julie S.
Published: June 2012

Geographic information systems (GIS) software is typically used for analyzing geographically distributed data, allowing users to annotate points or areas on a map and attach data for spatial analyses. While traditional GIS‐based research involves geo‐referenced data (points tied to geographic locations), the use of this technology has other constructive applications for physical anthropologists. The use of GIS software for the study of bone histology offers a novel opportunity to analyze the distribution of bone nano‐ and microstructures, relative to macrostructure and in comparison to other variables of interest, such as biomechanical loading history. This approach allows for the examination of characteristics of single histological features while considering their role at the macroscopic level. Such research has immediate promise in examining the load history of bone by surveying the functional relationship between collagen fiber orientation (CFO) and strain mode. The diversity of GIS applications that may be utilized in bone histology research is just beginning to be explored. The goal of this study is to introduce a reliable methodology for such investigation and our objective is to quantify the heterogeneity of bone microstructure over an entire cross‐section of bone using ArcGIS v 9.3 (ESRI). This was accomplished by identifying the distribution of remodeling units in a human metatarsal relative to bending axes. One biomechanical hypothesis suggests that CFO, manifested by patterns of birefringence, is indicative of mode of strain during formation. This study demonstrates that GIS can be used to investigate, describe, and compare such patterns through histological mapping. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.
Melt suspension crystallization for purification of phosphoric acid
Authors: Chen Aimei , Zhu Jiawen , Chen Kui , Wu Bin , Ji Lijun , Wu Yanyang
Published: June 2012

A continuous melt suspension crystallization process has been presented for the purification of the phosphoric acid in this study, which is conducted in the cascade of a continuous mixed suspension and mixed product removal (MSMPR) crystallization and subsequent countercurrent solid–liquid contact in a gravity wash column. With magma withdrawn from the MSMPR crystallizer being fed into the top of the gravity wash column, crystals settle down toward the bottom of column and the reflux melt rises upward, whereas the sweating of crystals and counter‐current contact between crystal particles and the melt lead to high separation capability of impurities. The gravity wash column used in this study is a vertical agitated cylindrical column, whose configuration is different from the inclined column crystallizer. The feasibility of suspension crystallization equipment for purification of phosphoric acid was studied. Distribution of impurities in the wash column was also investigated as a function of the feed concentration, crystal bed height, reflux ratio and stirring speed. Reflux ratio has been found to play an important role in the process. Food grade phosphoric acid can be achieved when the process is operated with feed concentrations of 84 ~ 86 wt.%, reflux ratios of 3.4 ~ 6.2, stirring speed of 10 rpm and crystal bed height of 150 ~ 250 mm in a gravity wash column. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Polymer nanocomposite‐based shielding against diagnostic X‐rays
Authors: Nambiar Shruti , Osei Ernest K. , Yeow John T. W.
Published: June 2012

Lead is commonly used in medical radiology departments as a shielding material. Lead‐based protective materials are also used by clinical personnel during X‐ray image‐guided interventional radiology (IVR) procedures. However, lead is extremely toxic and prolonged exposure to it can result in serious health concerns. Polymer composites, on the other hand, can be designed to be lead‐free in addition to being lightweight, conformable, cost effective, and potentially capable of significantly attenuating X‐rays. Nanomaterials have unique material properties that can be exploited to develop novel lead‐free radiation‐protection materials. In this study, polydimethylsiloxane (PDMS) nanocomposites were fabricated using different weight percentages (wt %) of bismuth oxide (BO) nanopowder. The attenuation properties of the nanocomposites were characterized using diagnostic X‐ray energies from 40 to 150 kV tube potential and were compared to the attenuation characteristics of 0.25‐mm‐thick pure lead sheet. The PDMS/BO nanocomposite (44.44 wt% of BO and 3.73‐mm thick) was capable of attenuating all the scattered X‐rays generated at a tube potential of 60 kV, which is the beam energy commonly employed in IVR. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Plasticized and nanofilled poly(lactic acid)‐based cast films: Effect of plasticizer and organoclay on processability and final properties
Authors: Scatto Marco , Salmini Elena , Castiello Stefania , Coltelli Maria‐Beatrice , Conzatti Lucia , Stagnaro Paola , Andreotti Leonardo , Bronco Simona
Published: June 2012

PLA‐based nanocomposites filled with the commercial organomodified montmorillonite Dellite 43B (D43B) and containing acetyl tri‐n‐butyl citrate (ATBC) as plasticizer were prepared by extrusion in a pilot‐scale twin‐screw extruder and melt casted into flexible films. A preliminary investigation was carried out in a laboratory batch mixer by varying blending conditions and addition procedures of the components. Indeed, the method of addition of ATBC and D43B considerably affected thermo‐mechanical properties and morphology of the resultant nanocomposites. The simultaneous introduction of both ATBC and D43B during the extrusion process allowed producing clearly exfoliated nanocomposite materials with modulated mechanical and thermal properties. Moreover, rheological results, obtained during melt extrusion, assessed the processability of nanofilled‐plasticized PLA, making this simple procedure interesting in view of the industrial production of nanostructured biomaterials based on plasticized PLA. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Viscoelastic properties of short aramid fibers‐reinforced rubbers
Authors: Shirazi M. , Talma A. G. , Noordermeer J. W. M.
Published: June 2012

Among short fiber‐reinforced composites, those with rubber matrices have gained great importance due to the advantages they have in processing and low cost, coupled with high strength. These composites combine the elastic behavior of rubbers with strength and stiffness of fibers. Reinforcement with short fibers offers attractive features such as design flexibility, high modulus, tear strength, etc. The degree of reinforcement depends upon many factors such as: the nature of the rubber matrix, the type of fiber, the concentration and orientation of the fibers, the fiber to rubber adhesion and fiber length. One of the main features related to this class of composites is their hysteretic properties which are of great importance especially in dynamic applications such as tire treads. In this research, short aramid fibers with different kinds of surface treatments: Standard finish and resorcinol formaldehyde latex (RFL)‐coating, have been applied in two different carbon black filled rubber compounds based on natural rubber (NR) and ethylene propylene diene rubber (EPDM). The dynamic properties of the compounds have been measured as influenced by the different kinds of fiber treatments on rubber‐fiber interaction. Finally, the contribution of the interfaces and/or interphase layers to the loss properties is characterized. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Fundamental studies on a new series of SPSEBS‐PVA‐QPSEBS bipolar membrane: Membrane preparation and characterization
Authors: Venugopal Krishnaveni , Dharmalingam Sangeetha
Published: June 2012

A sulfonated polystyrene ethylene butylene polystyrene (SPSEBS)‐poly(vinyl alcohol) (PVA)‐Quaternized polystyrene ethylene butylene polystyrene (QPSEBS) bipolar membrane (BPM) was prepared by lamination method using PSEBS as the starting material, the functionalization of which was modified by sulfonation and amination while PVA was used as the intermediate layer to enhance the water splitting efficiency. The cross section view of SPSEBS‐PVA‐QPSEBS BPM was studied by SEM. Fourier transform infra‐red spectroscopy (FTIR) studies indicated that the prepared BPM contained –SO, –NR, and –C‐N functional groups. The thermal stability of the prepared BPM was studied by thermogravimetric analysis (TGA). Some of the BPM characteristics results showed that the co‐ion fluxes was greater for t(0.065) when compared with t(0.051) along with a water splitting capacity value of 0.88 for SPSEBS‐PVA‐QPSEBS BPM. The water dissociation flux was 2.8 × 10−5 mol/m2/s and 2.2 × 10−5 mol/m2/s for the acid (H+) and base (OH−), respectively. The other essential current‐voltage characteristics and permeate flux across the membrane were also evaluated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci 2013
In situ silica reinforcement of vinyltriethoxysilane‐grafted styrene–butadiene rubber by sol–gel process
Authors: Yin Changjie , Zhang Qiuyu , Gu Junwei , Zheng Jucheng , Gong Guangbi , Liang Tao , Zhang Hepeng
Published: June 2012

Grafting polymerization of vinyltriethoxysilane (VTES) onto styrene–butadiene rubber (SBR) was firstly carried out in latex, using potassium persulfate (KPS) as initiator. The grafted SBR was further reinforced with silica produced by sol–gel reaction of tetraethoxysilane (TEOS). The grafted of VTES onto SBR was characterized and confirmed by ATR‐FTIR and 1H‐NMR. Results revealed that the addition of VTES could considerably improve the content of silica, bound rubber in SBR and utilized efficiency of TEOS. Meanwhile, the curing characteristics and mechanical properties of the vulcanized in situ reinforced SBR‐g‐VTES were also investigated and compared with that of the silica‐reinforced SBR prepared by mechanical mixing. The delta torque, tensile, and tear strength of in situ reinforced SBR‐g‐VTES were higher than that of silica‐reinforced SBR. Dynamic mechanical analysis showed that the interaction between silica and SBR of in situ reinforced SBR‐g‐VTES was also better than that of the silica‐reinforced SBR. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
A novel approach to prepare etoposide‐loaded poly(N‐vinyl caprolactam‐co‐methylmethacrylate) copolymeric nanoparticles and their controlled release studies
Authors: Shah Sunil , Pal Angshuman , Gude Rajiv , Devi Surekha
Published: June 2012

A series of copolymeric nanoparticles of methyl methacrylate and N‐vinylcaprolactam were synthesized from microemulsions containing sodium dodecyl sulfate. Etoposide as a model drug was loaded in nanoparticles during in situ polymerization. Stable nanolatex were produced and characterized for size and shape by dynamic light scattering (DLS) and transmission electron microscopy. Particles were found to be spherical in nature with size less than 50 nm. Structural characterization of copolymers was done by infrared and nuclear magnetic resonance spectroscopy. Differential scanning calorimetery (DSC) and X‐ray diffractometry (XRD) techniques were used to evaluate molecular level interaction of etoposide with nanoparticles. Drug encapsulation efficiency was determined by ultraviolet (UV) spectrometry and found to be 35–67%. DSC, XRD, and UV data suggested the molecular level dispersion of drug in the nanoparticles. In vitro release studies and in vitro cytotoxicity showed prolonged and controlled release of etoposide from nanoparticles along with IC50 values of nanoparticles in the range of 0.01–0.1 mg/mL. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Preparation and characterization of a novel strong‐base anion exchange fiber
Authors: Wang Jing , Lv Xiang Hua , Zhao Liang , Sha Baofeng , Zhao Dong , Zhu Chengshen
Published: June 2012

A novel strong‐base anion exchange fiber (QAPAN) was prepared in this study by preamination of a commercial poly(acrylonitrile) fiber followed by its subsequent grafting of glycidyl trimethylammonium chloride (GTA). The grafting conditions were optimized by conducting a L18 (37) orthogonal test; and properties of the prepared QAPAN were investigated by multiple analyses. Results showed that the optimal reaction conditions were GTA dosage 4 mL, temperature 60°C, reaction time 6 h, and volume ratio of water to dimethyl sulfoxide (DMSO) 0.5 : 0.5, among which volume ratio of water to DMSO was deemed as the most important factor on the QAPAN preparation. The prepared QAPAN had excellent fibrous morphology and fine mechanical stability, making its further processing feasible. Acid–base titration tests showed that the QAPAN had a total exchange capacity (TEC) of 6.34 mmol/g and a strong base capacity (SBC) of 1.34 mmol/g. Analyses of Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy further verified that the quaternary ammonium group was successfully grafted onto the QAPAN. This study provided a novel strong‐base anion exchange fiber as well as a simple and repeatable method for its preparation. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Poly(ethylene oxide)‐multiwall carbon nanotube composites: Effect of dicarboxylic acid salt‐based modifiers
Authors: Jagtap S. B. , Kushwaha R. K. , Ratna D.
Published: June 2012

An investigation was carried out to improve the dispersion of multiwall carbon nanotubes (MWCNTs) in the poly(ethylene oxide) (PEO) matrix using a half‐neutralized sodium salt of dicarboxylic acid with various number of carbon atoms. The effects of nature of various modifiers on mechanical properties of PEO were investigated. Among various dicarboxylic acid salts, half neutralized adipic acid (HNAA) is found to be highly effective in achieving the improvement in mechanical and dynamic mechanical properties due to improved dispersion of MWCNT in the PEO matrix. The physical interaction of HNAA with MWCNT (cation–π interaction) has been established using Fourier transform infrared and Raman spectroscopic analyses. Scanning electron microscope and transmission electron microscope (TEM) studies clearly indicate the improvement in the level of dispersion of MWCNT due to the addition of HNAA. Crystallization behavior of the PEO/MWCNT composites made with unmodified and modified MWCNT were studied by differential scanning colorimetry. Our approach is a noncovalent one and does not destroy the π‐electron clouds of MWCNT as opposed to chemical functionalization techniques and particularly attractive because of possibility of preserving the structural integrity of nanotubes as well as improved phase adhesion with polymer matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Shearing Mechanics and the Influence of a Flexible Symphysis During Oral Food Processing in Sphenodon (Lepidosauria: Rhynchocephalia)
Authors: Jones Marc E.H. , O'higgins Paul , Fagan Michael J. , Evans Susan E. , Curtis Neil
Published: June 2012

The New Zealand tuatara, Sphenodon, has a specialized feeding system in which the teeth of the lower jaw close between two upper tooth rows before sliding forward to slice food apart like a draw cut saw. This shearing action is unique amongst living amniotes but has been compared with the chewing power stroke of mammals. We investigated details of the jaw movement using multibody dynamics analysis of an anatomically accurate three‐dimensional computer model constructed from computed tomography scans. The model predicts that a flexible symphysis is necessary for changes in the intermandibular angle that permits prooral movement. Models with the greatest symphysial flexibility allow the articulation surface of the articular to follow the quadrate cotyle with the least restriction, and suggest that shearing is accompanied by a long axis rotation of the lower jaws. This promotes precise point loading between the cutting edges of particular teeth, enhancing the effectiveness of the shearing action. Given that Sphenodon is a relatively inactive reptile, we suggest that the link between oral food processing and endothermy has been overstated. Food processing improves feeding efficiency, a consideration of particular importance when food availability is unpredictable. Although this feeding mechanism is today limited to Sphenodon, a survey of fossil rhynchocephalians suggests that it was once more widespread. Anat Rec, 2012. © 2012 Wiley‐Periodicals, Inc.
Moonlighting is mainstream: Paradigm adjustment required
Authors: Copley Shelley D.
Published: June 2012

Moonlighting – the performance of more than one function by a single protein – is becoming recognized as a common phenomenon with important implications for systems biology and human health. The different functions of a moonlighting protein may use different regions of the protein structure, or alternative structures that occur due to post‐translational modifications and/or differences in binding partners. Often the different functions of moonlighting proteins are used at different times or in different places. The existence of moonlighting functions complicates efforts to understand metabolic and regulatory networks, as well as physiological and pathological processes in organisms. Because moonlighting functions can play important roles in disease processes, an improved understanding of moonlighting proteins will provide new opportunities for pharmacological manipulations that specifically target a function involved in pathology while sparing physiologically important functions.