bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Ar/H2 Plasma Pretreatments on Porous K=2.0 Dielectrics for Pore Sealing by Self-Assembled Monolayers Deposition
Authors: Sun Y. , Swerts J. , Verdonck P. , Maheshwari A. , Prado J.L. , de Feyter S. , Armini S.
Published: December 2012

Self-assembled monolayers (SAMs) deposition is being recently explored to help sealing the pores of a k=2.0 material. In order to enable a covalent chemical low-k surface functionalization by SAMs, a hydroxyl groups density as high as 1 to 2.5 OH groups/nm2 is required. This surface modification must be carefully controlled to confine the k below 10%. In this paper, the effects of plasma temperature, time and power on the SAMs deposition and plasma-induced damage are investigated. The main findings are that there is always a trade-off between surface hydroxyl groups density and bulk damage. A thick modified layer allows the SAM molecules to penetrate inside the pores which results in a decreased porosity and an increased k value with respect to correspondent plasma-treated pristine substrates.
Post Chemical Mechanical Polish Cleaning Chemistry for through Silicon via Process
Authors: Shang Cass , Maw Taishih , Coder Fadi
Published: December 2012

In order to achieve high cleaning efficiency requirement for post Chemical Mechanical Polish (CMP) cleaning in Through Silicon Via (TSV) application due to the aggressive CMP process. More comprehensive wafer defect evaluation techniques are needed to understand the cleaning mechanisms and assist the formulation design process. In this paper, the CSX-T series chemistry is applied to the post CMP cleaning process of various wafer substrates commonly used in TSV integration schemes. The data collected by several techniques are analyzed in detail and compared to demonstrate how and when it can be used in new formulation screening process to ensure good cleaning performance.
Implanted Photoresist Remover for Advanced Nodes Including SiGe, Ge and High K-Metals
Authors: Braun Simon , Vos Rita , Klipp Andreas , Claes Martine , Bittner Christian , Albert Johan , Horiguchi Naoto , Struyf Herbert
Published: December 2012

Cleaning photoresist from semiconductor wafers during the transistor formation in the front end of the line (FEOL) becomes more challenging with ever smaller nodes. First of all the resists do become more difficult to clean with decreasing node size, because implantation energy increase and the resist becomes more complex (to comply with the reduced wave length of the laser light for the lithography) at future node sizes. This results in more cross linked / polymerized photoresist, which is harder to (wet) strip. Additionally, the requirements on material compatibility of the cleaning solution increase, as more elements are used to build the transistor less than a monolayer of these materials can be removed during a single cleaning step.
Towards an Improved Megasonic Cleaning Process: Influence of Surface Tension on Bubble Activity in Acoustic Fields
Authors: Camerotto Elisabeth , Brems Steven , Hauptmann Marc , Lurquin Jelle , Struyf Herbert , Mertens Paul W. , De Gendt Stefan
Published: December 2012

Removal of particulate residues represents a very challenging step in current CMOS-technology nodes. The continued miniaturization and the introduction of novel materials in the semiconductor industry have resulted in very stringent requirements for device fabrication steps such as cleaning processes [. Physical forces, acting directly on the surface to be cleaned, are currently employed for delicate particle removal as an alternative to more aggressive chemistries [2]. High frequency ultrasounds (500 kHz 4 MHz), or megasonics, rely on the action of oscillating bubbles created during the ultrasonic agitation of the cleaning liquid. Strongly oscillating gas bubbles are able to generate shear forces, which are considered to be responsible for cleaning [3]. However, collapsing bubbles close to a surface can also produce water jets and shockwaves which lead to damage of fragile structures. Fundamental research is needed in order to overcome these issues by improving the understanding of the physical parameters playing a role in the acoustic cavitation of bubbles. This study reports the effects of lowering the surface tension of the liquid bulk on the bubble activity in the MHz range. A lower surface tension (45 mN/m) with respect to water (72 mN/m) is obtained by adding a non-ionic surface-active agent (TritonX-100). After fully characterizing its wettability, a cleaning solution containing surfactant is investigated under pulsed and continuous acoustic fields, for different acoustic amplitudes and gas concentrations. The aim is to increase bubble activity while reducing the strength of the bubble collapse. The results obtained can be useful in tuning megasonic cleaning systems towards more efficient processes.
Influence of Dissolved CO2 on Bubble Activity in Pulsed Acoustic Fields
Authors: Brems Steven , Hauptmann Marc , Camerotto Elisabeth , Pacco Antoine , Struyf Herbert , Heyns Marc M. , Mertens Paul W. , De Gendt Stefan , Gottschalk Christiane
Published: December 2012

The continuous miniaturization of electronic building blocks in the semiconductor industry imposes more stringent requirements on the different cleaning processes. Purely chemical particle cleaning is based on weak etching of the substrate. This etching reduces the attractive van de Waals interaction between particle and substrate and at the same time, electrostatic repulsion ensures the removal of particles. This technique is not applicable anymore for future technology nodes, since an unacceptable large substrate loss (up to 3 nm) is necessary to obtain high particle removal efficiencies with pure chemical cleaning alone [. As a result, an additional physical force has to be considered to overcome this limitation. Several physical cleaning techniques exist, but all of them suffer from too much damage creation when fragile structures are cleaned. Currently, the industry is more focusing on spray cleaning and state-of-the-art spray tools show a high control over droplet size and droplet velocity [2]. Despite all of the advancements in spray cleaning, damage creation of fragile elements remains an issue, which could partially be attributed to the chaotic behavior of the water layer on the wafer surface [3]. Therefore, megasonic cleaning is still considered as a possible alternative to reduce damage formation during a physical cleaning process. Recently, it has been shown that the acoustic pressure amplitude can be reduced while maintaining the same particle removal efficiency level. This is achieved by (1) using pulsed acoustic fields which makes it possible to control the average bubble size and maximize the number of resonant bubbles, by (2) increasing the dissolved gas concentration which facilitates bubble nucleation and, finally, by (3) introducing traveling waves to transport bubbles to the wafer surface which needs to be cleaned. These conditions are briefly discussed and are applied during the investigation of the influence of dissolved CO2on bubble activity. Dissolved CO2is particularly interesting since it has been reported that sonoluminescence (i.e. strong bubble collapse) as well as damage formation is reduced when CO2is added to the cleaning liquid [4,5]. Here, it is shown that also particle removal efficiencies (PREs) diminish with increasing CO2concentrations.
Non Destructive Nanoparticle Removal from Submicron Structures Using Megasonic Cleaning
Authors: Karimi Pegah , Busnaina Ahmed A. , Kang Bong Kyun , Park Jin Goo
Published: December 2012

The removal of nanoparticles from patterned wafers is one of the main challenges facing the semiconductor industry. As the size of structures shrinks with each new generation of devices, it becomes more difficult to remove nanoscale particles. Nanostructures (specially, poly silicon lines) were found to be vulnerable to damage as a result of cavitation when megasocnic cleaning is utilized. Megasonics utilizes acoustic streaming to reduce the acoustic boundary layer and utilize the generated pulsating flow to remove nanoscale particles from trenches and other structures on the wafer. Although Megasonics is believed to be a solution for many of these cleaning challenges, it has been shown to cause damage to nanoscale device structures such as poly-silicon lines.
Direct vs. Indirect Megasonic Tank Cleaning Systems; Uniformity, Cleaning Efficiency and Cost of Ownership
Authors: Desagher J. , Dussault Don , Beck M. , Lillard R. , Liebscher Eric
Published: December 2012

High frequency (1 MHz, megasonic) acoustic enhanced cleaning is a well established method of removing surface particles in semiconductor manufacturing processes. There are two fundamental designs of megasonic batch cleaning systems, indirect and direct.
Development of a Near-Field Megasonic Cleaning System for Nano-Particle Removal
Authors: Kim Hyun Se , Lee Yang Lae , Lim Eui Su
Published: December 2012

A near-field megasonic system for cleaning semiconductors was designed and fabricated. For the design of the near-field megasonic system, an impedance characteristic of a quartz megasonic waveguide with the piezoelectric actuator was analyzed using a finite element method (FEM). The analysis result showed that the anti-resonance frequency of the system was 982 kHz, which agreed well with the measured value of 988 kHz. The performance of the developed system was assessed by measuring acoustic pressures and comparing the maximim values of them with a conventional megasonic system. As a result, the maximim acoustic pressure of the developed system was decreased by 46.2% compared to the commercial system. Finally, the particle removal efficiency (PRE) test was performed and the obtained PRE was 90.8%. Theses results explain that the developed megasonic has an improved uniformity of the acoustic pressures, which can raise the energy efficiency of the system and lowering the consumption of chemical and ultra pure water (UPW).
Investigation of the Evaporation and Wetting Mechanism of IPA-DIW Mixtures
Authors: Xu Xiu Mei , Smeers Jens , Vereecke Guy , Struyf Herbert
Published: December 2012

In semiconductor fabrication, mixtures of isopropyl alcohol (IPA) and deionized water (DIW) are commonly used in wafer cleaning processes due to their superior wetting and drying performance on many types of substrates. To achieve a maximum cleaning performance with reduced IPA consumption, it is of great interest to understand the wetting mechanism of such mixtures. In this work, we investigate the spreading and evaporation process of IPA-DIW drops with different concentrations.
Influence of Ammonia Gas Ambient in IPA Drying Process of the Single Wafer Cleaning System
Authors: Hagimoto Yoshiya , Iwamoto Hayato , Kawabuchi Yosuke , Minami Teruomi
Published: December 2012

High-performance drying techniques using IPA (isopropyl alcohol) are widely used in the silicon wafer cleaning process. IPA-based drying techniques help prevent the formation of watermarks because they effectively displace any water remaining on a wafer surface. They are thus frequently used in the single wafer cleaning system for advanced devices in which ultra-clean process performance is required. However, as devices are becoming physically smaller, the formation of extremely small defects during cleaning has become a serious problem. It is therefore important to elucidate the mechanism of the defect formation and to take measures to prevent it for future device technologies in which small-size defects can be killer defects during production. In this paper, we performed experiments focused on the process chamber atmosphere in IPA drying of the single wafer cleaning system and describe the mechanism of the defect formation.
Advanced Vacuum Wafer Drying for Thermal Laser Separation Dicing Assessment Results from European Collaborative “SEAL” Project
Authors: Le Barillec Olivier , Davenet Magali , Favre Arnaud , Bellet Bertrand , Koitzsch Matthias , Lewke Dirk , Schellenberger Martin , Zühlke Hans Ulrich
Published: December 2012

Based on recent progress on laser-based wafer dicing equipment and process, the partners adixen, Fraunhofer IISB and JENOPTIK investigated the use of a vacuum based decontamination process to dry and to decontaminate the substrate surface of the diced wafers from water residuals, which are a side-effect of the TLS (thermal laser separation) approach. The decontamination process was achieved by using an adixen vacuum drying module prototype further to the JENOPTIK TLS dicing process. Within the frame of the European collaborative project SEAL, supported by the European Commission, experimental assessment was conducted by Fraunhofer IISB (research institution) together with JENOPTIK and Adixen.
Diffusion Behavior of Transition Metals Penetrating Silicon Substrate through Silicon Dioxides by Dopant Ion Implantation
Authors: Saga Koichiro
Published: December 2012

Metallic contamination on silicon surfaces has a detrimental impact on ULSI device performance and yield. Surface metal impurities degrade gate oxide integrity while metal impurities dissolved in silicon cause recombination centers and result in junction leakage. Surface metal impurities penetrate silicon by the colliding with dopant during ion implantation and are also diffused in silicon by subsequent annealing [. The diffusion behavior of metal impurities in silicon is well-known [. While metal impurities often penetrate silicon through the silicon oxide in ULSI processing, little work has been reported on the diffusion behavior of metal impurities penetrating silicon oxide. We demonstrated the diffusion behavior of metal impurities penetrating silicon substrates with different thickness of silicon oxide by the collision with dopant during ion implantation.
Evaluation of Hafnium Contamination on Wafer Surfaces after the Wet Cleaning Process
Authors: Saito Suguru , Hagimoto Yoshiya , Iwamoto Hayato
Published: December 2012

High-k gate dielectrics and metal gate electrodes have become essential for emerging device technologies because they enable the continuous scaling down of devices while maintaining a high performance [. However, since they are composed of novel metallic elements that have never before been used in conventional processes, special care must be taken when handling these materials in the production line. In particular, cross-contamination that occurs due to transporting contamination via processed wafers can cause serious problems such as deterioration of device properties and yield loss [. The process of cleaning the backside and bevel of a wafer is now increasingly important for avoiding these problems. To date, there has been no detailed evaluation of contamination removal on various films performed for elements such as hafnium, which is one of the key elements in high-k/metal gate technologies. In this study, we evaluated hafnium contamination on three types of wafer surface after the cleaning process and investigated the cause of different residual amounts of hafnium contamination on the different wafers.
Characterization of Surface Metal Contaminations on Fused Quartz
Authors: Liu Shi , Liu Bin
Published: December 2012

Micro-contamination exerts ever-increasing adverse impact on semiconductor manufacturing as device integration scale keeps increasing and device geometry continues decreasing. In particular, contaminations from particles, trace metals, and/or organic compounds can reduce device yield, quality, and reliability [. Metallic impurities from materials used for process equipment are one of the major contamination sources.
How to Overcome the Effects of Silicon Build-Up during Solar Cell Wet Chemical Processing
Authors: Kashkoush Ismail , Rieker J. , Chen G. , Nemeth D. , Danel A.
Published: December 2012

Although the chemical reaction is well known, the anisotropic etching of Si in alkaline solutions is a complex process. This is particularly true in the solar industry where a large mass of silicon is typically introduced into the etch bath. The etch by-products (silicates) affect the balance of the etching specie. If adequate compensation is not made for these by-products, a significant drop in etch rate and an increase in contamination levels is typically noticed. Because of this contamination, production lines would suffer from unpredictable wafer characteristics and hence lower cell performance.
Optimized Wet Processes and PECVD for High-Efficiency Solar Cells
Authors: Kashkoush I. , Chen G. , Nemeth D. , Rieker J.
Published: December 2012

The semiconductor industry considers wet cleans to be critical surface preparation steps. The Si/SiO2 interface, for example, is very critical to achieve high gate oxide integrity and avoid leakage or stacking faults. Similarly, the solar industry has seen the value of wet processes to achieve best cell performance. In this study, we highlight the effect of pre-cleans, texturization and final cleans on cell parameters. We also studied the importance of coupling these wet cleaning and texturization steps with the PECVD steps to achieve the film quality required for highest solar cell efficiency.
Silicon & beyond CMOS: The Path of Advanced Electronic Structure Engineering for Low-Voltage Transistors
Authors: Thean Aaron
Published: December 2012

With the continuing growth of data bandwidth, next-generation information technology demands circuit and device scaling to meet performance, form-factor and cost needs. With increase performance and circuit density, reduction in power dissipation has become paramount for both high-performance and low-power applications. In the case of high-performance systems, heat dissipation becomes the thermal bottle neck. Limited by battery, low-power mobile applications ration energy to maintain user multimedia experience while on the move. Lowering supply voltage (Vdd) is becoming the major system enabler to manage the power challenges.
Wet Chemical Oxidation of Silicon Surfaces Prior to the Deposition of All-PECVD AlOx/a-SiNx Passivation Stacks for Silicon Solar Cells
Authors: Laades Abdelazize , Angermann Heike , Sperlich Hans Peter , Stürzebecher Uta , Álvarez Carlos Alberto Díaz , Bähr Mario , Lawerenz Alexander
Published: December 2012

Aluminum oxide (AlOx) is currently under intensive investigation for use in surface passivation schemes in solar cells. AlOx films contain negative charges and therefore generate an accumulation layer on p-type silicon surfaces, which is very favorable for the rear side of p-type silicon solar cells as well as the p+-emitter at the front side of n-type silicon solar cells. However, it has been reported that quality of an interfacial silicon sub-oxide layer (SiOx), which is usually observed during deposition of AlOx on Silicon, strongly impacts the silicon/AlOx interface passivation properties [1]. The present work demonstrates that a convenient way to control the interface is to form thin wet chemical oxides of high quality prior to the deposition of AlOx/a-SiNx:H stacks by the plasma enhanced chemical vapor deposition (PECVD).
Wet Etching Behavior of Poly-Si in TMAH Solution
Authors: Takahashi Hiroaki , Otsuji Masayuki , Snow Jim , Sebaai Farid , Arai Kenichiro , Sato Masanobu , Nadahara Soichi
Published: December 2012

Since Tetramethylammonium Hydroxide (TMAH) became widely used as a silicon etchant, e.g. the dummy gate removal for gate-last approach (RMG) [1, or Si fin formation on FinFET [, some careful preparations and optimizations have required implementation. These adaptations have involved not only chemical-related issues, but also hardware-related in order to satisfy the necessary process performance.
SiO2 Etch Rate Modification by Ion Implantation
Authors: Bellandi E. , Soncini V.
Published: December 2012

It is well known that etch rate of dielectric thin films, such as silicon dioxide, increases after ion implantation. A study of the structural damage created in SiO2films by ion implantation can be found in references [,]. It is reported that nuclear collision of implanted ion with target ions produces a relevant rearrangement of in SiO2target network: Si and O target atoms are moved from their original positions to new positions where original local atomic coordination is not recovered. As final result, damage consists mainly of Si-O broken bonds and non-bridging oxygen.
Cleaning Technology for Advanced Devices beyond 20 nm Node
Authors: Ogawa Yoshihiro
Published: December 2012

Several attempts have recently been made to use novel high-k dielectric materials, such as AlxOy, HfxAlyOz, HfxSiyOz, and HfxOy, to improve electrical device characteristics of advanced devices. Moreover, it is becoming increasingly important in the ULSI manufacturing process to suppress contamination by metal or particles from the wafer backside or edge. This paper reviews the wafer backside/edge control technology for suppression of metal contamination.
Evaluation of CD Fluctuation on QC Monitor
Authors: Yen Chuan Yu , Luo Mu Chien , Huang Kuo Bin , Wang Ting Chun
Published: December 2012

The continually increasing complexity of IC integration drives the reduction of device dimensions. Because of this, material loss that alters the device critical dimension (CD) continues to be an important parameter to monitor for device performance. The processes used in advanced device generations therefore need to be well defined to maintain the correct CD. The basic processes used to define the profile were (i) photolithography for device patterning, (ii) dry etch and ash to form the profile and (iii) caros clean for photoresist strip [1]. The lithography and etch tools were critical to fine tune the CDs for each device generation. The accuracy of the CD monitor was very important for tool tuning and optimization. However the basic QC monitor results showed the CD data was more unstable on the patterned monitor wafer requiring additional tool tuning that was not required on the device wafer.
ALD Growth Behavior of High-K Nanolayers on Various Substrates Characterized by X-Ray Spectrometry in Gracing Incidence Geometry
Authors: Müller Matthias , Sioncke Sonja , Delabie Annelies , Beckhoff Burkhard
Published: December 2012

Thin films of high-k material are becoming more and more used for semiconductor devices. A further shrinking of the devices requires also a further reduction of the high-k film thickness. With this reduction of the high-k thickness down to just a few nanometers two technical challenges have to be addressed. The first one is the ALD process for the deposition of the high-k material. Usually the ALD process can be well controlled by tuning the number of process cycles. But it is theoretically predicted [1] that the growth-per-cycle of the first cycles can be different than the steady growth-per-cycle which is obtained for high cycle numbers. This effect is caused by a not fully covered initial surface during the first cycles. Only when the deposited material forms a closed surface and the surface probabilities are the same for each following cycle the deposition rate will be constant. The second challenge is that the electrical properties of thin films with a thickness of a few nanometers are significantly determined by the quality of the interface between the film and the substrate.
Inflammatory Monocytes Are Critical for Induction of a Polysaccharide-Specific Antibody Response to an Intact Bacterium
Authors: Chen Quanyi , Snapper Clifford M.
Published: December 2012

Although inflammatory monocytes (IM) (CD11b+Ly6Chi cells) have been shown to play important roles in cell-mediated host protection against intracellular bacteria, protozoans, and fungi, their potential impact on humoral immune responses to extracellular bacteria are unknown. IM, localized largely to the splenic marginal zone of naive CD11b–diphtheria toxin (DT) receptor bone marrow–chimeric mice were selectively depleted following treatment with DT, including no reduction of CD11b+ peritoneal B cells. Depletion of IM resulted in a marked reduction in the polysaccharide (PS)-specific, T cell–independent IgM, and T cell–dependent IgG responses to intact, heat-killed Streptococcus pneumoniae with no effect on the associated S. pneumoniae protein–specific IgG response or on the PS- and protein-specific IgG responses to a soluble pneumococcal conjugate vaccine. IM acted largely within the first 48 h following the initiation of the immune response to S. pneumoniae to induce the subsequent production of PS-specific IgM and IgG. Adoptive transfer of highly purified IM from wild-type mice into DT-treated CD11b–DT receptor mice completely restored the defective PS-specific Ig response to S. pneumoniae. IM were phenotypically and functionally distinct from circulating CD11b+CD11clowLy6G/C cells (immature blood dendritic cells), previously described to play a role in Ig responses to S. pneumoniae, in that they were CD11c− as well as Ly6Chi and did not internalize injected S. pneumoniae during the early phase of the response. These data are the first, to our knowledge, to establish a critical role for IM in the induction of an Ig response to an intact extracellular bacterium.
Paraganglioma with unusual presentation in parotid gland: A diagnostic dilemma in fine needle aspiration
Authors: Vora Anagh A. , Lai Chi K. , Rao Jian Yu , Apple Sophia K. , Moatamed Neda A.
Published: December 2012

Paragangliomas (PGLs) are uncommon tumors. Although PGLs are known to occur in the head and neck region, especially the carotid body, middle ear, and larynx, involvement of the parotid glands has not been reported. In this article, we report the fine needle aspiration features of tumor in an unusual location, presenting as a parotid gland mass, submitted to pathology for initial diagnosis. The clinical presentation, cytomorphology, and the immunohistochemical features for the diagnosis are described. To our knowledge, this is the first case of paraganglioma of the parotid gland reported in the literature.
Intestinal Obstruction from Congenital Bands at the Proximal Jejunum: A Case Report and Literature Review
Authors: Sarkar Debkumar , Gongidi Preetam , Presenza Thomas , Scattergood Emily
Published: December 2012

Congenital anomalous bands at the proximal jejunum resulting in obstruction have been described sporadically in the literature and are otherwise rare. We present a case of an 8 year-old girl with a nine-month history of intermittent vomiting and no history of prior surgery. The imaging workup includes an abdominal ultrasound, a single contrast upper gastrointestinal series, and a dual contrast computed tomography of the abdomen and pelvis. Surgical intervention revealed the presence of dense bands at the proximal jejunum without evidence of malrotation. Our report reviews the embryology and radiologic findings of this entity using different imaging modalities.
Non-Azygos Accessory Fissure in Right Upper Lobe Associated with Superior and Inferior Accessory Fissures in Right Lower Lobe
Authors: Muttikkal Thomas Jose Eluvathingal , Deng Chunli
Published: December 2012

Accessory fissures in the lungs are common congenital variations, usually detected as incidental findings in radiographs or CT scan. Accessory fissures can act as an anatomic barrier to the spread of inflammatory or neoplastic disease, as well as due to the variant anatomy, mimic lesions. It is important to recognize the presence of accessory fissures, as they affect surgical planning of pulmonary lobectomy and segmentectomy. Accessory fissure in the right upper lobe other than due to the anomalous course of azygos vein is very rare. We report a case of non-azygos accessory fissure, between the apical and the anterior segments of right upper lobe, along with superior and inferior accessory fissures in the right lower lobe.
Knowledge, Attitudes, and Practices Related to Leptospirosis among Urban Slum Residents in Brazil
Authors: Navegantes de Araújo Wildo , Finkmoore Brooke , Ribeiro Guilherme S. , Reis Renato B. , Felzemburgh Ridalva D. M. , Hagan José E. , Reis Mitermayer G. , Ko Albert I. , Costa Federico
Published: December 2012

Leptospirosis disproportionately affects residents of urban slums. To understand the knowledge, attitudes, and practices regarding leptospirosis, we conducted a cross-sectional study among residents of an urban slum community in Salvador, Brazil. Of the 257 residents who were interviewed, 225 (90%) were aware of leptospirosis and more than two-thirds of respondents correctly identified the modes of disease transmission and ways to reduce exposure. However, study participants who performed risk activities such as cleaning open sewers had limited access to protective clothing such as boots (33%) or gloves (35%). Almost all respondents performed at least one activity to prevent household rat infestation, which often included use of an illegal poison. Our findings support the need for interventions targeted at the individual and household levels to reduce risk of leptospirosis until large-scale structural interventions are available to residents of urban slum communities.
Fatal Nosocomial Spread of Crimean-Congo Hemorrhagic Fever with Very Short Incubation Period
Authors: Naderi HamidReza , Sheybani Fereshte , Bojdi Amin , Khosravi Nasrin , Mostafavi Irandokht
Published: December 2012

Crimean-Congo hemorrhagic fever is a tick-borne viral zoonosis with the potential of human-to-human transmission with case fatality rates from 3% to 50%. The incubation period depends on host, route of infection, and viral dose. Herein, we report a nosocomial spread of the disease in a hospital at Mashhad, northeastern Iran, with a very short incubation period for one of the secondary cases. The patient was a medical student who had a negligible contact with a Crimean-Congo hemorrhagic fever patient during his admission to the hospital. The time interval between the contact and the onset of symptoms was merely 20 hours. Unfortunately, he died within 1 week of exposure.
Placenta and Transvaginal Sonography
Authors: Khurana Ashok
Published: December 2012

In recent years, transvaginal evaluation of the placenta has completely changed the way obstetricians need to perceive and assess a low-lying placenta. Additionally, the number of negative ultrasound examinations in morbid placental adherence has reduced. This article presents the evidence on the safety and accuracy of transvaginal placental evaluation and goes on to discuss the manner in which transvaginal findings should alter clinical protocols to optimize maternal and fetal outcomes. It also answers a very pertinent clinical question: How low is low?

How to cite this article

Khurana A. Placenta and Transvaginal Sonography. Donald School J Ultrasound Obstet Gynecol 2012;6(4):391-397.
Sonography of the Pelvic Infection
Authors: Pérez-Medina Tirso , Arenas Jose Bajo
Published: December 2012

We describe sonographic findings of pelvis inflammatory disease. The diagnosis of initial acute PID (acute salpingitis) begins with a challenge for the doctor, due to the little sensibility of the clinic's criteria. The accumulation of pus inside the fallopian tube gives a location for the tubaric abscess or pyosalpinx, whose characteristic signal is the presence of purulent material in considerable quantities and is visible by means of a sonograph inside the tubal light. We refer a series of characteristic sings that advise us.

How to cite this article

Arenas JB, Perez-Medina T. Sonography of the Pelvic Infection. Donald School J Ultrasound Obstet Gynecol 2012;6(4):398-407.
Pentalogy of Cantrell: A Report of One Case at the Yaounde Central Hospital in Cameroon
Authors: Fouedjio Jeanne Hortence , Ymele Florent Fouelifack , Kenfack Bruno , Mehta Mandana , Mbu Robinson Enow
Published: December 2012

Pentalogy of Cantrell is a rare multiple congenital malformation syndrome characterized by a combination of five features: A midline supraumbilical abdominal wall defect; a defect of the lower sternum; a defect of the diaphragmatic pericardium; deficiency of the anterior diaphragm and congenital cardiac anomalies. These defects can be diagnosed as early as the first trimester of pregnancy. The complexity of these anomalies, in particular the presence of any cardiac defects, determines the management as well as the prognosis. We report a case of pentalogy of Cantrell diagnosed by ultrasound at 32 weeks of gestational age, the fetus died 3 hours after delivery.

How to cite this article

Ymele FF, Fouedjio JH, Kenfack B, Mehta M, Mbu RE. Pentalogy of Cantrell: A Report of One Case at the Yaounde Central Hospital in Cameroon. Donald School J Ultrasound Obstet Gynecol 2012;6(4):412-414.
The Role of Three-dimensional Ultrasound in the Assessment of Congenital Uterine Anomalies
Authors: Tabi Sarah
Published: December 2012

Three-dimensional (3D), two-dimensional (2D) ultrasound and saline infusion sonography (SIS) are beneficial tools in diagnosing congenital uterine anomalies. This article illustrates six various case scenarios based on 3D ultrasound images in order to review the concepts of ultrasound diagnosis of congenital uterine anomalies and apply it to the presented case studies. These cases scenarios educate the reader on arcuate uterus, septate uterus, bicornuate uterus, didelphic uterus, uterus duplex and unicornuate uterus. This article also presents the sequence of embryologic events leading to the congenital uterine anomalies. The role of 3D ultrasound in diagnosis and treatment of congenital uterine anomalies is presented, along with its advantages over 2D ultrasound, SIS, X-ray hysterosalpingography, magnetic resonance imaging, hysteroscopy and laparoscopy. The effects of hysteroscopic metroplasty on fertility are also illustrated and discussed. After this case-based discussion is completed, the readers will be able to make a differential diagnosis of the different types of congenital uterine anomalies.

How to cite this article

Tabi S, Kupesic Plavsic S. The Role of Three-dimensional Ultrasound in the Assessment of Congenital Uterine Anomalies. Donald School J Ultrasound Obstet Gynecol 2012;6(4):415-423.
Semiparametric Gaussian Variance-Mean Mixtures for Heavy-Tailed and Skewed Data
Authors: Cui Kai
Published: December 2012

There is a need for new classes of flexible multivariate distributions that can capture heavy tails and skewness without being so flexible as to fully incur the curse of dimensionality intrinsic to
nonparametric density estimation. We focus on the family of Gaussian variance-mean mixtures, which have received limited attention in multivariate settings beyond simple special cases. By using a Bayesian semiparametric approach, we allow the data to infer about the unknown mixing distribution. Properties are considered and an approach to posterior computation is developed relying on Markov chain Monte Carlo. The methods are evaluated through simulation studies and applied to a variety of applications, illustrating their flexible performance in characterizing heavy tails, tail dependence, and skewness.
The Relationships between Cholesterol and Suicide: An Update
Authors: De Berardis Domenico , Marini Stefano , Piersanti Monica , Cavuto Marilde , Perna Giampaolo , Valchera Alessandro , Mazza Monica , Fornaro Michele , Iasevoli Felice , Martinotti Giovanni , Di Giannantonio Massimo
Published: December 2012

Cholesterol is a core component of the central nervous system, essential for the cell membrane stability and the correct functioning of neurotransmission. It has been observed that cholesterol may be somewhat associated with suicidal behaviours. Therefore, the aim of this paper was to elucidate current facts and views about the role of cholesterol levels in mood disorders. The majority of the studies reviewed in the present paper suggest an interesting relationship between cholesterol (especially lower levels) and suicidality. On the other hand, particularly during the last years, relationships between serum cholesterol and suicidality were doubted on the basis of some recent studies that have not found any correlation. However, the debate on relationships between cholesterol and suicide is open and longitudinal studies on a larger sample of patients are needed to further clarify this important issue.
A Review of Hot-Melt Extrusion: Process Technology to Pharmaceutical Products
Authors: Maniruzzaman Mohammed , Boateng Joshua S. , Snowden Martin J. , Douroumis Dennis
Published: December 2012

Over the last three decades industrial adaptability has allowed hot-melt extrusion (HME) to gain wide acceptance and has already established its place in the broad spectrum of manufacturing operations and pharmaceutical research developments. HME has already been demonstrated as a robust, novel technique to make solid dispersions in order to provide time controlled, modified, extended, and targeted drug delivery resulting in improved bioavailability as well as taste masking of bitter active pharmaceutical ingredients (APIs). This paper reviews the innumerable benefits of HME, based on a holistic perspective of the equipment, processing technologies to the materials, novel formulation design and developments, and its varied applications in oral drug delivery systems.
Antenatal Corticosteroids for Late-Preterm Infants: A Decision-Analytic and Economic Analysis
Authors: Bastek Jamie A. , Langmuir Holly , Kondapalli Laxmi A. , Paré Emmanuelle , Adamczak Joanna E. , Srinivas Sindhu K.
Published: December 2012

Objectives. Antenatal corticosteroids (ACS) are not routinely administered to patients at risk for delivery between 34 and 36 6/7 weeks. Our objective was to determine whether ACS are cost-effective for late-preterm infants at risk for imminent preterm delivery. We hypothesized that the preferred strategy <36 weeks would include ACS while the preferred strategy ≥36 weeks would not. Methods. We performed decision-analytic and cost-effectiveness analyses to determine whether ACS was cost-effective at 34, 35, and 36 weeks. We conducted a literature review to determine probability, utility, and cost estimates absent of patient-level data. Base-case cost-effectiveness analysis, univariable sensitivity analysis, and Monte Carlo simulation were performed. A threshold of $100,000/QALY was considered cost-effective. Results. The incremental cost-effectiveness ratio favored the administration of a full course of ACS at 34, 35, and 36 weeks ($62,888.25/QALY, $64,425.67/QALY, and $64,793.71/QALY, resp.). A partial course of ACS was not cost-effective. While ACS was the consistently dominant strategy for acute respiratory outcomes, all models were sensitive to changes in variables associated with chronic respiratory disease. Conclusions. Our findings suggest that the administration of ACS to patients at risk of imminent delivery 34-36 weeks could significantly reduce the cost and acute morbidity associated with late-preterm birth.
Interleukin-17 Expression in the Barrett’s Metaplasia-Dysplasia-Adenocarcinoma Sequence
Authors: Bannister J. R. , Khan A. L. , Eccleston D. W. , Deol-Poonia R. K. , Hughes S. F.
Published: December 2012

Introduction. This pilot study evaluated the expression of the proinflammatory cytokine IL-17 along the Barrett’s metaplasia-dysplasia-adenocarcinoma sequence by establishing the expression levels of IL-17 in columnar epithelium, intestinal metaplastic cells, and dysplastic/glandular neoplastic cells. Immunohistochemical techniques were used to examine the accumulation of the proinflammatory cytokine IL-17 in forty (n=40) formalin-fixed, paraffin-embedded oesophageal archived specimens across a range of endoscopic diagnostic categories, and a highly significant difference was found, where P≤0.001, in IL-17 expression (Kruskall Wallis and Mann-Whitney U) between all the cell types examined. There was also a strong positive correlation (Spearman's rank correlation) between disease progression and IL-17 expression (rs=0.883, P<0.001, n=29), IL-17 expression was absent or absent/weak in columnar epithelium, weak to moderate in columnar metaplastic cells, and moderate to strong in dysplastic/neoplastic cells, which demonstrated that the elevation of IL-17 expression occurs in the progression of the disease. Understanding the differential expression of IL-17 between benign and malignant tissue potentially has a significant diagnostic, prognostic, and therapeutic value. Ultimately, this selective biomarker may be employed in routine clinical practice for the screening of oesophageal adenocarcinoma.
Credit Portfolios, Credibility Theory, and Dynamic Empirical Bayes
Authors: Lai Tze Leung
Published: December 2012

We begin with a review of (a) the pricing theory of multiname credit derivatives to hedge the credit risk of a portfolio of corporate bonds and (b) current approaches to modeling correlated default intensities. We then consider pricing of insurance contracts using credibility theory in actuarial science. After a brief discussion of the similarities and differences of both pricing theories, we propose a new unified approach, which uses recent advances in dynamic empirical Bayes modeling, to evolutionary credibility in insurance rate-making and default modeling of credit portfolios.
Review and Progress towards the Common Broadband Management of High-Voltage Transmission Grids: Model Expansion and Comparative Modal Analysis
Authors: Lazaropoulos Athanasios G.
Published: December 2012

The need of bridging the digital gap between underdeveloped/developed areas and promoting smart grid (SG) networks urges the deployment of broadband over power lines (BPL) systems and their further integration. The contribution of this paper is fourfold. First, based on the well-established hybrid model of (Lazaropoulos and Cottis 2009, 2010, Lazaropoulos, 2012) and the generic multidimensional network analysis tool presented in (Lazaropoulos 2012, Sartenaer 2004, Sartenaer and Delogne 2006, 2001) an exact multidimensional chain scattering matrix method, which is suitable for overhead high-voltage/broadband over power lines (HV/BPL) networks, is proposed and is evaluated against other theoretical and experimental proven models. Second, the proposed method investigates the overhead HV/BPL transmission grids (overhead 150 kV single-circuit, 275 kV double-circuit, and 400 kV double-circuit multiconductor structures) with regard to their end-to-end signal attenuation. It is found that the above features depend drastically on the overhead power grid type, the frequency, the MTL configuration, the physical properties of the cables used, the end-to-end distance, and the number, the length, and the terminations of the branches encountered along the end-to-end BPL signal propagation. Third, the impact of the multiplicity of the branches at the same junction in overhead HV grids is first examined. Based on the inherent long-branch structure and the quasi-static behavior of single/multiple branches with matched terminations of overhead HV grid, a simple approach suitable for overhead HV/BPL channel estimation is presented. Fourth, identifying the similar characteristics among different overhead HV/BPL configurations, an additional step towards the common overhead HV/BPL analysis is demonstrated; the entire overhead HV/BPL grid may be examined under a common PHY framework regardless of the overhead HV/BPL grid type examined. Finally, apart from the presentation of broadband transmission potential of the entire overhead transmission power grid, a consequence of this paper is that it helps towards: (i) the better broadband monitoring and management of overhead HV transmission power grids in an interactive SG network; and (ii) the intraoperability/interoperability of overhead HV/BPL systems under the aegis of a unified transmission/distribution SG power network.
Lipoprotein Receptors and Lipid Enzymes in Hepatitis C Virus Entry and Early Steps of Infection
Authors: Pécheur Eve-Isabelle
Published: December 2012

Viruses are obligate intracellular agents that depend on host cells for successful propagation, hijacking cellular machineries to their own profit. The molecular interplay between host factors and invading viruses is a continuous coevolutionary process that determines viral host range and pathogenesis. The hepatitis C virus (HCV) is a strictly human pathogen, causing chronic liver injuries accompanied by lipid disorders. Upon infection, in addition to protein-protein and protein-RNA interactions usual for such a positive-strand RNA virus, HCV relies on protein-lipid interactions at multiple steps of its life cycle to establish persistent infection, making use of hepatic lipid pathways. This paper focuses on lipoproteins in HCV entry and on receptors and enzymes involved in lipid metabolism that HCV exploits to enter hepatocytes.
Alterations of Hormone-Sensitive Adenylyl Cyclase System in the Tissues of Rats with Long-Term Streptozotocin Diabetes and the Influence of Intranasal Insulin
Authors: Shpakov Alexander O. , Derkach Kira V. , Moyseyuk Irina V. , Chistyakova Oksana V.
Published: December 2012

One of the causes of complications in type 1 diabetes mellitus (T1DM) is the changes in adenylyl cyclase (AC) signaling system, identified on the early stages of the disease. However, the most significant disturbances in this system occur on the later stages of T1DM, which ultimately leads to severe complications, but functional state of the AC system in late T1DM is poorly understood. The aim of this work was to study alterations in AC system sensitive to biogenic amines and polypeptide hormones in the heart, brain, and testes of male rats with long-term, 7-month, streptozotocin T1DM and to assess the influence on them of 135-day therapy with intranasal insulin. It was shown that AC effects ofβ-adrenergic agonists in the heart, serotonin receptor agonists and PACAP-38 in the brain, chorionic gonadotropin and PACAP-38 in the testes, and somatostatin in all investigated tissues in long-term T1DM were drastically decreased. The treatment with intranasal insulin (0.48 IU/day) significantly restored these effects. The results were obtained suggesting that long-term T1DM induces significant alterations in hormone-sensitive AC system in the heart, brain, and testes that are much more pronounced, compared with short-term T1DM, and include a large number of hormonal regulations.
Brønsted Acid‐Catalyzed Four‐Component Cascade Reaction: Facile Synthesis of Hexahydroimidazo[1,2‐a]pyridines
Authors: Wang Ren‐Lin , Zhu Ping , Lu Yu , Huang Fu‐Ping , Hui Xin‐Ping
Published: December 2012

An efficient four‐component cascade reaction for the synthesis of trisubstituted hexahydroimidazo[1,2‐a]pyridines starting from readily available aldehydes, ketones and ethane‐1,2‐diamine catalyzed by p‐toluenesulfonic acid is described. Two new cycles and five new bonds are constructed with all reactants being efficiently utilized in this transformation. The mechanism of the reaction was investigated and some crucial reaction intermediates were observed.
Copper(I)‐Catalyzed [3+2] Cycloaddition/Ring‐Opening Rearrangement/[4+2] Cycloaddition/Aromatization Cascade: An Unprecedented Chemo‐ and Stereoselective Three Component Coupling of Sulfonyl Azide, Alkyne and N‐Arylidenepyridin‐2‐ amine to Pyrido[1,2‐a]pyrimidin‐4‐imine
Authors: Namitharan Kayambu , Pitchumani Kasi
Published: December 2012

A novel synthetic protocol for the one‐pot chemo‐ and stereoselective construction of diversely functionalized pyrido[1,2‐a]pyrimidin‐4‐imines via copper(I)‐catalyzed [3+2] cycloaddition/ring‐opening rearrangement/[4+2] cycloaddition/aromatization cascade of sulfonyl azides, alkynes and N‐arylidenepyridin‐2‐amines under mild reaction conditions is reported. In addition, the catalytic activity of copper(I)‐modified zeolite, a recyclable, heterogeneous catalyst is also investigated, which gives improved yield compared to its homogeneous equivalents.
Tunable Phosphine‐Mediated Domino Reaction: Selective Synthesis of 2,3‐Dihydrofurans and Biaryls
Authors: Xie Peizhong , Li Erqing , Zheng Jie , Li Xin , Huang You , Chen Ruyu
Published: December 2012

We have developed a novel strategy to control the product distribution between 2,3‐dihydrofurans and biaryls from the same starting materials by tuning the catalytic or stoichiometric process. By controlling the loading of the phosphine PR3, the Morita–Baylis–Hillman carbonates can be selectively used as a C1 or a C3 synthon, respectively. This investigation has given new insights into tunable domino reactions and will be useful in diversity‐oriented synthesis (DOS).