bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of depressed skull fractures in neonates using percutaneous microscrew elevation
Authors: Zalatimo Omar , Ranasinghe Moksha , Dias Mark , Iantosca Mark
Published: June 2012

Depressed skull fractures in neonates involve the inward buckling of the skull bones to resemble a cup shape or “ping-pong ball” shape. In the past, several methods have been used to treat these fractures for cosmetic effect, including the use of vacuum extraction. The aim of this study was to demonstrate the use of a novel treatment method for these skull fractures. All patients presented to Hershey Medical Center between May 2007 and March 2010. All underwent treatment of their ping-pong skull fracture using a novel technique of percutaneous screw elevation with self-tapping microscrews (4 or 5 mm) typically used in neurosurgery for cranial plating. Four patients were treated, all between the ages of 2 days and 4 months. Two of the patients were treated under general anesthesia and 2 with local anesthesia only. All patients had good cosmetic results and experienced no adverse events. Percutaneous screw elevation of the ping-pong type, simple depressed skull fracture in neonates is a feasible method of treatment with a low complication rate associated with the procedure and no risk from anesthesia.
Complex pediatric cervical spine surgery using smaller nonspinal screws and plates and intraoperative computed tomography
Authors: Karandikar Mahesh , Mirza Sohail K. , Song Kit , Yang Tong , Krengel Walter F. , Spratt Kevin F. , Avellino Anthony M.
Published: June 2012

Object

The treatment of craniocervical instability in children is often challenging due to their small spine bones, complex anatomy, and unique syndromes. The authors discuss their surgical experience with 33 cases in the treatment of 31 children (≤17 years of age) with craniocervical spine instability using smaller nontraditional titanium screws and plates, as well as intraoperative CT.

Methods

All craniocervical fusion procedures were performed using intraoperative fluoroscopic imaging and electrophysiological monitoring. Nontraditional spine hardware included smaller screw sizes (2.4 and 2.7 mm) from the orthopedic hand/foot set and mandibular plates. Twenty-three of the 33 surgical procedures were performed with intraoperative CT, which was used to confirm adequate position of the spine hardware and alignment of the spine.

Results

The mean patient age was 9.5 years (range 2–17 years). Eleven children underwent a posterior C1–2 transarticular screw fusion, 17 had an occipitocervical fusion, and 3 had a posterior subaxial cervical fusion. The follow-up duration ranged from 9 to 72 months (mean 53 months). All children demonstrated successful fusion at their 3-month follow-up visit, except 1 patient whose unilateral C1–2 transarticular screw fusion required a repeat surgery before proper fusion was achieved. Of the 47 C1–2 transarticular screws that were placed, 13 were 2.4 mm, 15 were 2.7 mm, 7 were 3.5 mm, and 12 were 4.0 mm. Eighteen of the 47 C1–2 transarticular screws were suboptimally placed. Eleven of these misplaced screws were removed and redirected within the same operation because these surgeries benefitted from the use of intraoperative CT; 6 of the 7 remaining suboptimally placed screws were left in place because a second surgery for screw replacement was not warranted. The other suboptimally placed C1–2 screw was replaced during a repeat operation due to failure of fusion. Use of intraoperative CT was invaluable because it enabled the authors to reposition suboptimal C1–2 transarticular screws without necessitating a second operation.

Conclusions

Successful craniocervical fusion procedures were achieved using smaller nontraditional titanium screws and plates. Intraoperative CT was a helpful adjunct for confirming and readjusting the trajectory of the screws prior to leaving the operating room, which decreases overall treatment costs and reduces complications.
Clinical evaluation and surveillance imaging in children with spina bifida aperta and shunt-treated hydrocephalus
Authors: Chern Joshua J. , Muhleman Mitchel , Tubbs R. Shane , Miller Joseph H. , Johnston James M. , Wellons John C. , Blount Jeffrey P. , Oakes W. Jerry , Rozzelle Curtis J.
Published: June 2012

Object

Most children with spina bifida aperta have implanted CSF shunts. However, the efficacy of adding surveillance imaging to clinical evaluation during routine follow-up as a means to minimize the hazard of shunt failure has not been thoroughly studied.

Methods

A total of 396 clinic visits were made by patients with spina bifida aperta and shunt-treated hydrocephalus in a spina bifida specialty clinic during the calendar years 2008 and 2009 (initial clinic visit). All visits were preceded by a 6-month period during which no shunt evaluation of any kind was performed and were followed by a subsequent visit in the same clinic. At the initial clinic visit, 230 patients were evaluated by a neurosurgeon (clinical evaluation group), and 166 patients underwent previously scheduled surveillance CT scans in addition to clinical evaluation (surveillance imaging group). Subsequent unexpected events, defined as emergency department (ED) visits and caregiver-requested clinic visits, were reviewed. The time to an unexpected event and the likelihood of event occurrence in each of the 2 groups were compared using Cox proportional hazards survival analysis. The outcome and complications of shunt surgeries were also reviewed.

Results

The clinical characteristics of the 2 groups were similar. In the clinical evaluation group, 2 patients underwent shunt revision based on clinical findings in the initial visit. In the subsequent follow-up period, there were 27 visits to the ED and 25 requested clinic visits that resulted in 12 shunt revisions. In the surveillance imaging group, 11 patients underwent shunt revision based on clinical and imaging findings in the initial visit. In the subsequent follow-up period, there were 15 visits to the ED and 9 requested clinic visits that resulted in 8 shunt revisions. Patients who underwent surveillance imaging on the day of initial clinic visit were less likely to have an unexpected event in the subsequent follow-up period (relative risk 0.579, p = 0.026). The likelihood of needing shunt revision and the morbidity of shunt malfunction was not significantly different between the 2 groups.

Conclusions

Surveillance imaging in children with spina bifida aperta and shunted hydrocephalus decreases the likelihood of ED visits and caregiver-requested clinic visits in the follow-up period, but based on this study, its effect on mortality and morbidity related to shunt malfunction was less clear.
First preoperative functional mapping via navigated transcranial magnetic stimulation in a 3-year-old boy
Authors: Coburger Jan , Karhu Jari , Bittl Markus , Hopf Nikolai J.
Published: June 2012

Preoperative functional mapping in children younger than 5 years old remains a challenge. Awake functional MRI (fMRI) is usually not an option for these patients. Except for a description of passive fMRI in sedated patients and magnetoencephalography, no other noninvasive mapping method has been reported as a preoperative diagnostic tool in children. Therefore, invasive intraoperative direct cortical stimulation remains the method of choice. To the authors' knowledge, this is the first case of a young child undergoing preoperative functional motor cortex mapping with the aid of navigated transcranial magnetic stimulation (nTMS).

In this 3-year-old boy with a rolandic ganglioglioma, awake preoperative mapping was performed using nTMS. A precise location of Broca area 4 could be established. The surgical approach was planned according to the preoperative findings. Intraoperative direct cortical stimulation verified the location of the nTMS hotspots, and complete resection of the precentral tumor was achieved.

Navigated TMS is a precise tool for preoperative motor cortex mapping and is feasible even in very young pediatric patients. In children for whom performing the fMRI motor paradigm is challenging, nTMS is the only available option for functional mapping.
Complications of occipital screw placement for occipitocervical fusion in children
Authors: Hwang Steven W. , Gressot Loyola V. , Chern Joshua J. , Relyea Katherine , Jea Andrew
Published: June 2012

Object

Occipitocervical stabilization in the pediatric age group remains a challenge because of the regional anatomy, poor occipital bone purchase, and, in some instances, significant thinning of the occipital bone. Multiple bicortical fixation points to the occipital bone may be required to increase construct rigidity. The authors evaluated the complications of bicortical occipital screw placement in children with occipital fusion constructs.

Methods

The records of 20 consecutive pediatric patients who had undergone occipitocervical fusion between September 1, 2007, and November 30, 2010, at Texas Children's Hospital were reviewed.

Results

The patients consisted of 10 girls and 10 boys, ranging in age from 10 months to 16 years (mean ± SD, 7.7 ± 5.1 years). Two patients were lost to follow-up, 2 died for reasons unrelated to the surgery, and the remaining patients had at least 3 months of follow-up (mean 14 ± 11.8 months) with evaluation via dynamic radiography and CT. Four patients experienced 8 complications: 2 CSF leaks, 2 vigorous venous bleedings, worsening of quadriparesis, wound infection, radiographic pseudarthrosis, and transient dysphagia. Among 114 screws, there were 2 cases of intraoperative dural venous sinus injury and 2 cases of intraoperative CSF leakage, without clinical sequelae from these complications. Only 1 case of radiographic pseudarthrosis was identified in a patient with skeletal dysplasia and a prior failed C1–2 posterior arthrodesis. There were no difficulties with wound healing because of prominent occipital instrumentation, and there was only 1 wound infection.

Conclusions

Data in this report confirm that including bicortical occipital screw placement in occipitocervical constructs in children may result in a high fusion rate but at the cost of a notable complication rate.
Split cord malformation Type II with twin dorsal lipomas
Authors: Salunke Pravin , Futane Sameer S. , Aggarwal Ashish
Published: June 2012

Although uncommon, variations in split cord malformation (SCM) have been described. However, a combination of SCM Type II and dorsal lipomas has not been reported.

The authors describe the case of a 6-year-old girl who presented with a 1-year history of spastic paraparesis associated with a lipomatous swelling on her lower back. Radiology revealed a Type II SCM with a dorsal lipoma at that level. Intraoperatively, the authors observed a dorsal lipoma for each hemicord; these were excised, and the septum causing the split was cut.

Premature separation of the cutaneous and neural ectoderm is predetermined for each neural fold, and a split at this level would give rise to SCM with twin dorsal lipomas, one for each hemicord.
Spinal cord infarction remote from maximal compression in a patient with Morquio syndrome
Authors: Tong Calvin K. W. , Chen James C. H. , Cochrane D. Douglas
Published: June 2012

Morquio syndrome, or mucopolysaccharidosis type IV, is a rare enzyme deficiency disorder and results in skeletal dysplasia. Odontoid dysplasia is common among affected patients, resulting in atlantoaxial instability and spinal cord compression. Surgical treatments include decompression and prophylactic fusion, during which intraoperative neuromonitoring is important to alert the surgical team to changes in cord function so that they can prevent or mitigate spinal cord injury. This report describes a 16-year-old girl with Morquio syndrome who developed paraplegia due to thoracic spinal cord infarction during foramen magnum and atlantal decompression. This tragic event demonstrates the following: 1) that patients with Morquio syndrome are at risk for ischemic spinal cord injury at levels remote from areas of maximal anatomical compression while under anesthesia in the prone position, possibly due to impaired cardiac output; 2) the significance of absent motor evoked potential responses in the lower limbs with preserved upper-limb responses in an ambulatory patient; 3) the importance of establishing intraoperative neuromonitoring baseline assessments prior to turning patients to the prone position following induction of anesthesia; and 4) the importance of monitoring cardiac output during prone positioning in patients with chest wall deformity.
Growing skull fracture stages and treatment strategy
Authors: Liu Xue-song , You Chao , Lu Ma , Liu Jia-gang
Published: June 2012

Object

A growing skull fracture (GSF) is a rare but significant late complication of skull fractures, usually occurring during infancy and early childhood. Delayed diagnosis and improper treatment could exacerbate this disease. The aim of this study was to introduce a new hypothesis about, describe the stages of, and discuss the treatment strategy for GSF.

Methods

The authors performed a retrospective review of 27 patients with GSF, who were grouped according to 3 different GSF stages.

Results

Over a period of 20 years, 27 patients with GSF (16 males and 11 females) were treated in the authors' department. The mean follow-up period was 26.5 months. Six patients were in the prephase of GSF (Stage 1), 10 patients in the early phase (Stage 2), and 11 in the late phase (Stage 3). All patients underwent duraplasty. All 6 patients at Stage 1 and 5 patients at Stage 2 underwent craniotomy without cranioplasty. Five patients at Stage 2 and all of the patients at Stage 3 underwent cranioplasty with autologous bone and alloplastic materials, respectively. Among all patients, 5 underwent ventriculoperitoneal shunt placement.

Symptoms in all patients at Stages 1 and 2 were alleviated or disappeared, and the cranial bones developed without deformity during follow-up. Among patients with Stage 3 GSF, no obvious improvement in neurological deficits was observed. Three patients underwent additional operations because of cranial deformation or infection.

Conclusions

The authors identify the stages of GSF according to a new hypothesis. They conclude that accurately diagnosing and treating GSF during Stages 1 and 2 leads to a better prognosis.
Cerebrospinal fluid fistula prevention and treatment following frontal sinus fractures: a review of initial management and outcomes
Authors: Castro Brandyn , Walcott Brian P. , Redjal Navid , Coumans Jean-Valery , Nahed Brian V.
Published: June 2012

Frontal sinus fractures are heterogeneous, and management of these fractures is often modified based on injury pattern and institutional experience. The optimal initial treatment of frontal sinus fractures is controversial. Treatment strategies are aimed at correcting cosmetic deformity, as well as at preventing delayed complications, including CSF fistulas, mucocele formation, and infection. Existing treatment options include observation, reconstruction, obliteration, cranialization, or a combination thereof. Modalities for treatment encompass both open surgical approaches and endoscopic techniques. In the absence of Class I data, the authors review the existing literature related to treatment strategies of frontal sinus fractures, particularly as they relate to CSF fistulas, to provide recommendations based on the best available evidence.
Surgical nuances for the endoscopic endonasal transpterygoid approach to lateral sphenoid sinus encephaloceles
Authors: Schmidt Richard F. , Choudhry Osamah J. , Raviv Joseph , Baredes Soly , Casiano Roy R. , Eloy Jean Anderson , Liu James K.
Published: June 2012

Lateral sphenoid encephaloceles of the Sternberg canal are rare entities and usually present with spontaneous CSF rhinorrhea. Traditionally, these were treated via transcranial approaches, which can be challenging given the deep location of these lesions. However, with advancements in endoscopic skull base surgery, including improved surgical exposures, angled endoscopes and instruments, and novel repair techniques, these encephaloceles can be resected and successfully repaired with purely endoscopic endonasal approaches. In this report, the authors review the endoscopic endonasal transpterygoid approach to the lateral recess of the sphenoid sinus for repair of temporal lobe encephaloceles, including an overview of the surgical anatomy from an endoscopic perspective, and describe the technical operative nuances and surgical pearls for these cases. The authors also present 4 new cases of lateral sphenoid recess encephaloceles that were successfully treated using this approach.
Repair of middle fossa cerebrospinal fluid leaks using a novel combination of materials: technical note
Authors: Shorter Cedric D. , Connor David E. , Thakur Jai Deep , Gardner Gale , Nanda Anil , Guthikonda Bharat
Published: June 2012

Object

Methods for repairing middle fossa CSF (MFCSF) leaks have varied and yielded mixed results. The objective of this study was to evaluate the safety and durability of the authors' repair technique using a novel combination of 3 synthetic materials.

Methods

The authors performed a retrospective case review of patients treated for CSF leaks between January 2009 and September 2011. Eight patients were found to have undergone middle fossa craniotomies for CSF leaks. Inclusion criteria for the study included age greater than 18 years, neuroimaging-documented temporal bone defect, and symptoms consistent with CSF leaks or gross CSF otorrhea. Seven patients, 3 men and 4 women, met the inclusion criteria, and their charts were reviewed. Hydroxyapatite cement, collagen-based dural substitute matrix, and polyethylene glycol hydrogel sealant were used in all patients for the repair.

Results

In all patients the MFCSF leaks were successfully repaired. Initial presenting symptoms included CSF otorrhea in 4 patients (57.1%), hearing loss in 3 (42.9%), and CSF rhinorrhea in 1 (14.3%). The mean follow-up duration was 12 months (range 5–33 months). In 1 patient an epidural hematoma developed at the operative site on postoperative Day 2, and in another patient a superficial wound dehiscence occurred on postoperative Day 48. During the follow-up period, the authors found no evidence of wound infections, neurovascular damage, or CSF leakage requiring reoperation.

Conclusions

The middle fossa approach involving a combination of hydroxyapatite cement, collagen-based dural substitute matrix, and polyethylene glycol hydrogel sealant is a safe, effective method for repairing MFCSF leaks. The combination of synthetic materials provides an alternative to existing materials for skull base surgeons.
Extent of tumor removal and molecular markers in cerebral glioblastoma: a combined prognostic factors study in a surgical series of 105 patients
Authors: Salvati Maurizio , Pichierri Angelo , Piccirilli Manolo , Floriana Brunetto Giacoma Maria , D'Elia Alessandro , Artizzu Spartaco , Santoro Francesca , Arcella Antonietta , Giangaspero Felice , Frati Alessandro , Simione Luca , Santoro Antonio
Published: June 2012

Object

In this paper, the authors' goal was to evaluate the prognostic value of YKL-40 expression as a prognostic factor for glioblastomas and to compare its validity to the already known MGMT.

Methods

Between January 2002 and January 2007, 105 patients were treated for cerebral glioblastoma. The extent of removal was classified in 4 groups. YKL-40 expression was evaluated by a semiquantitative immunohistochemical staining scale (0, no staining; 1, mild expression; and 2, strong expression). MGMT promoter methylation status was analyzed with methylation-specific polymerase chain reaction. All patients received adjuvant radiotherapy and chemotherapy. Kaplan-Meier curves were used to analyze progression-free survival (PFS) and overall survival (OS), and to compare these parameters between the subgroups stratified by extent of surgical removal, MGMT methylation, and YKL-40 expression. The log-rank test was used to determine statistical significance. A multivariate regression analysis was applied to extent of removal, YKL-40 expression, and MGMT status to check their specific statistical power and to test the independence of the variables.

Results

There were 55 men and 50 women with a mean age of 58 years. Extent of surgical removal is reported. The MGMT promoter was methylated in 48 patients and nonmethylated in 57. Analysis of YKL-40 expression is reported. The median PFS was 10.7 months (14.9 months in the gross-total removal subgroup) (p < 0.0001), and the median OS was 12.5 months (17.4 months in the gross-total removal group) (p < 0.0001). In the univariate analysis, OS was significantly correlated to the extent of resection (p < 0.0001), MGMT status (p < 0.0001), and YKL-40 (p < 0.0001). Multivariate analysis showed that all 3 factors reached statistical significance with respect to patient survival. In particular, surgical removal contributed more than the 2 other factors to the survival prediction (β = −0.6254). Interestingly, YKL-40 (β = −0.3867) contributed more than MGMT (β = −0.1705) to the predicted survival.

Conclusions

The extent of removal is the most important factor influencing the OS of patients harboring glioblastomas. When biological aggressiveness is taken into account, YKL-40 expression was found to be an independent prognostic factor that predicts OS better than MGMT status.
Retroperitoneal schwannoma treated with percutaneous computed tomography–guided radiofrequency ablation
Authors: Zhao Ming , Li Xishan , Wang Jianpeng , Li Wang , Huang Zilin
Published: June 2012

Retroperitoneal schwannomas (RSs) are particularly rare tumors, and resection is the first choice for symptomatic patients. However, some RSs with anatomical complexities pose great challenges for surgeons attempting radical resection without sacrificing the nearby critical structures, and subtotal resection leads to local recurrence, especially in refractory malignant RSs. The authors have successfully applied percutaneous CT-guided radiofrequency ablation in 2 cases of RSs, with favorable long-term progression-free survival.
Natural Killer (NK)- and T-Cell Engaging Antibody-Derived Therapeutics
Authors: Stein Christoph , Schubert Ingo , Fey Georg H.
Published: June 2012

Unmodified antibodies (abs) have been successful in the treatment of hematologic malignancies, but less so for the treatment of solid tumors. They trigger anti-tumor effects through their Fc-domains, and one way to improve their efficacy is to optimize their interaction with the effectors through Fc-engineering. Another way to empower abs is the design of bispecific abs and related fusion proteins allowing a narrower choice of effector cells. Here we review frequently chosen classes of effector cells, as well as common trigger molecules. Natural Killer (NK)- and T-cells are the most investigated populations in therapeutical approaches with bispecific agents until now. Catumaxomab, the first bispecific ab to receive drug approval, targets the tumor antigen Epithelial Cell Adhesion Molecule (EpCAM) and recruits T-cells via a binding site for the cell surface protein CD3. The next generation of recombinant ab-derivatives replaces the broadly reactive Fc-domain by a binding domain for a single selected trigger. Blinatumomab is the first clinically successful member of this class, targeting cancer cells via CD19 and engaging T-cells by CD3. Other investigators have developed related recombinant fusion proteins to recruit effectors, such as NK-cells and macrophages. The first such agents currently in preclinical and clinical development will be discussed.
Symptom Persistence and Memory Performance in Posttraumatic Stress Disorder: A Gene X Environment Pilot Study
Authors: David Annie-Claude , Thakur Geeta A. , Akerib Vivian , Armony Jorge , Rouleau Isabelle , Brunet Alain
Published: June 2012

The FKBP5 gene, a glucocorticoid receptor (GR)-regulating co-chaperone of stress proteins, is of special interest because of its role in hypothalamic-pituitary-adrenal (HPA)-axis regulation. However, studies finding a genetic relationship between posttraumatic stress disorder (PTSD) and the FKBP5 gene have failed to distinguish between the development and persistence of PTSD, thereby limiting the prognostic usefulness of such a finding. The present study sought to longitudinally explore this question by examining the association between four single-nucleotide polymorphisms (SNPs) in the FKBP5 gene (rs3800373, rs9470080, rs1360780, and rs9296158), the persistence of PTSD (severity and diagnostic status), and memory performance among twenty-two treatment-seekers diagnosed with acute PTSD. Results showed that the four SNPs significantly interacted with improvement in PTSD symptoms as well as PTSD diagnostic status. Individuals homozygous for the dominant allele and having experienced higher levels of peritraumatic responses subsequently showed more memory dysfunction. The results of this study suggest that SNPs in the FKBP5 gene are associated with symptom persistence and memory dysfunction in acute PTSD.
Perforin Expression by CD4+ Regulatory T Cells Increases at Multiple Sclerosis Relapse: Sex Differences
Authors: Tejera-Alhambra Marta , Alonso Bárbara , Teijeiro Roseta , Ramos-Medina Rocío , Aristimuño Carol , Valor Larissa , De Andrés Clara , Sánchez-Ramón Silvia
Published: June 2012

Multiple sclerosis (MS) represents the leading cause of neurological deficit among young adults, affecting women more frequently than men. In MS, the extent of central nervous system lesions is determined by the net balance between self-reactive and regulatory T-cells at any given time, among other factors, as well as by the effect of inflammatory response. Here, we studied both CD4+ and CD8+ TReg in parallel in blood and CSF during MS relapse. A recruitment of both regulatory CD4+ and CD8+ T cells (TReg) within the cerebrospinal fluid (CSF) takes place during MS relapse. Not previously described, the presence of CD4+ TReg in CSF was higher in women than in men, which could account for the sexual dimorphism in the incidence of MS. A direct correlation between plasma oestradiol (E2) and IL-2 levels was observed, in line with a putative circuit of E2 and perforin expression by CD4+ TReg playing a role in MS. Also, serum IFN-alpha was higher in females, with direct correlation with serum E2 levels. This is the first study to analyze perforin expression by CD4+ TReg in MS, which was greatly enhanced in CSF, what points out a relevant role of this molecule in the suppressive effects of the CD4+ TReg in MS, and contributes to the understanding of MS pathophysiology.
8-Oxoguanine DNA Glycosylases: One Lesion, Three Subfamilies
Authors: Faucher Frédérick , Doublié Sylvie , Jia Zongchao
Published: June 2012

Amongst the four bases that form DNA, guanine is the most susceptible to oxidation, and its oxidation product, 7,8-dihydro-8-oxoguanine (8-oxoG) is the most prevalent base lesion found in DNA. Fortunately, throughout evolution cells have developed repair mechanisms, such as the 8-oxoguanine DNA glycosylases (OGG), which recognize and excise 8-oxoG from DNA thereby preventing the accumulation of deleterious mutations. OGG are divided into three subfamilies, OGG1, OGG2 and AGOG, which are all involved in the base excision repair (BER) pathway. The published structures of OGG1 and AGOG, as well as the recent availability of OGG2 structures in both apo- and liganded forms, provide an excellent opportunity to compare the structural and functional properties of the three OGG subfamilies. Among the observed differences, the three-dimensional fold varies considerably between OGG1 and OGG2 members, as the latter lack the A-domain involved in 8-oxoG binding. In addition, all three OGG subfamilies bind 8-oxoG in a different manner even though the crucial interaction between the enzyme and the protonated N7 of 8-oxoG is conserved. Finally, the three OGG subfamilies differ with respect to DNA binding properties, helix-hairpin-helix motifs, and specificity for the opposite base.
Mark Burgin’s Theory of Information
Authors: Brenner Joseph E.
Published: June 2012

A review of a major, definitive source book on the basis of information theory is presented.
Influences of Sample Preparation on Nanoindentation Behavior of a Zr-Based Bulk Metallic Glass
Authors: Huang Hu , Zhao Hongwei , Zhang Zhiyu , Yang Zhaojun , Ma Zhichao
Published: June 2012

Influences of two different sample preparation methods, mechanical polishing and plunge cutting, on nanoindentation behavior of a Zr-based bulk metallic glass were studied. Mechanical polishing suppresses the serrated flow but promotes the creep. In contrast, plunge cutting promotes the serrated flow but suppresses the creep. However, hardness and elastic modulus obtained from these two methods are nearly the same.
Comparison of Polytetrafluoroethylene Flat-Sheet Membranes with Different Pore Sizes in Application to Submerged Membrane Bioreactor
Authors: Nittami Tadashi , Hitomi Tetsuo , Matsumoto Kanji , Nakamura Kazuho , Ikeda Takaharu , Setoguchi Yoshihiro , Motoori Manabu
Published: June 2012

This study focused on phase separation of activated sludge mixed liquor by flat-sheet membranes of polytetrafluoroethylene (PTFE). A 20 liter working volume lab-scale MBR incorporating immersed PTFE flat-sheet membrane modules with different pore sizes (0.3, 0.5 and 1.0 μm) was operated for 19 days treating a synthetic wastewater. The experiment was interrupted twice at days 5 and 13 when the modules were removed and cleaned physically and chemically in sequence. The pure water permeate flux of each membrane module was measured before and after each cleaning step to calculate membrane resistances. Results showed that fouling of membrane modules with 0.3 μm pore size was more rapid than other membrane modules with different pore sizes (0.5 and 1.0 μm). On the other hand, it was not clear whether fouling of the 0.5 μm membrane module was more severe than that of the 1.0 μm membrane module. This was partly because of the membrane condition after chemical cleaning, which seemed to determine the fouling of those modules over the next period. When irreversible resistance (Ri) i.e., differences in membrane resistance before use and after chemical cleaning was high, the transmembrane pressure increased quickly during the next period irrespective of membrane pore size.
Characterisation and Mechanical Testing of Open Cell Al Foams Manufactured by Molten Metal Infiltration of Porous Salt Bead Preforms: Effect of Bead Size
Authors: Jinnapat Appichart , Kennedy Andrew
Published: June 2012

Preforms made from porous salt beads with different diameters (0.5–1.0, 1.4–2.0 and 2.5–3.1 mm) have been infiltrated with molten Al to produce porous structures using pressure-assisted vacuum investment casting. Infiltration was incomplete for preforms with high densities. At higher infiltration pressures, penetration of molten Al occurred into beads of all sizes and was predicted using a simple model. The yield strength of the porous structures increased with increasing density and decreasing pore (bead) size. Despite the non-optimum distribution of metal in the porous structure, due to partial infiltration within the beads, the magnitude and density dependence of the yield stress were comparable with those for pure Al foams reported in similar studies. The structural efficiency was improved for structures produced at lower infiltration pressure, where the metal is predominantly distributed in the cell walls. The rate of salt dissolution from the preforms was high, in particular for high density preforms, large beads and preforms infiltrated at low pressures, owing to the ability of the porous beads to collapse as well as dissolve.
Synthesis and Antibacterial Activity of Some Heterocyclic Chalcone Analogues Alone and in Combination with Antibiotics
Authors: Tran Thanh-Dao , Nguyen Thi-Thao-Nhu , Do Tuong-Ha , Huynh Thi-Ngoc-Phuong , Tran Cat-Dong , Thai Khac-Minh
Published: June 2012

A series of simple heterocyclic chalcone analogues have been synthesized by Claisen Schmidt condensation reactions between substituted benzaldehydes and heteroaryl methyl ketones and evaluated for their antibacterial activity. The structures of the synthesized chalcones were established by IR and 1H-NMR analysis. The biological data shows that compounds p5, f6 and t5 had strong activities against both susceptible and resistant Staphylococcus aureus strains, but not activity against a vancomycin and methicillin resistant Staphylococcus aureus isolated from a human sample. The structure and activity relationships confirmed that compounds f5, f6 and t5 are potential candidates for future drug discovery and development.
Simple, Rapid and Reliable Preparation of [11C]-(+)-a-DTBZ of High Quality for Routine Applications
Authors: Zhang Jinming , Zhang Xiaojun , Li Yungang , Tian Jiahe
Published: June 2012

[11C]-(+)-a-DTBZ has been used as a marker of dopaminergic terminal densities in human striatum and expressed in islet beta cells in the pancreas. We aimed to establish a fully automated and simple procedure for the synthesis of [11C]-(+)-a-DTBZ for routine applications. [11C]-(+)-a-DTBZ was synthesized from a 9-hydroxy precursor in acetone and potassium hydroxide with [11C]-methyl triflate and was purified by solid phase extraction using a Vac tC-18 cartridge. Radiochemical yields based on [11C]-methyl triflate (corrected for decay) were 82.3% ± 3.6%, with a specific radioactivity of 60 GBq/mmol. Time elapsed was less than 20 min from end of bombardment to release of the product for quality control.
Calculation of the Stabilization Energies of Oxidatively Damaged Guanine Base Pairs with Guanine
Authors: Suzuki Masayo , Kino Katsuhito , Morikawa Masayuki , Kobayashi Takanobu , Komori Rie , Miyazawa Hiroshi
Published: June 2012

DNA is constantly exposed to endogenous and exogenous oxidative stresses. Damaged DNA can cause mutations, which may increase the risk of developing cancer and other diseases. G:C-C:G transversions are caused by various oxidative stresses. 2,2,4-Triamino-5(2H)-oxazolone (Oz), guanidinohydantoin (Gh)/iminoallantoin (Ia) and spiro-imino-dihydantoin (Sp) are known products of oxidative guanine damage. These damaged bases can base pair with guanine and cause G:C-C:G transversions. In this study, the stabilization energies of these bases paired with guanine were calculated in vacuo and in water. The calculated stabilization energies of the Ia:G base pairs were similar to that of the native C:G base pair, and both bases pairs have three hydrogen bonds. By contrast, the calculated stabilization energies of Gh:G, which form two hydrogen bonds, were lower than the Ia:G base pairs, suggesting that the stabilization energy depends on the number of hydrogen bonds. In addition, the Sp:G base pairs were less stable than the Ia:G base pairs. Furthermore, calculations showed that the Oz:G base pairs were less stable than the Ia:G, Gh:G and Sp:G base pairs, even though experimental results showed that incorporation of guanine opposite Oz is more efficient than that opposite Gh/Ia and Sp.
Bluetooth Based Chaos Synchronization Using Particle Swarm Optimization and Its Applications to Image Encryption
Authors: Yau Her-Terng , Hung Tzu-Hsiang , Hsieh Chia-Chun
Published: June 2012

This study used the complex dynamic characteristics of chaotic systems and Bluetooth to explore the topic of wireless chaotic communication secrecy and develop a communication security system. The PID controller for chaos synchronization control was applied, and the optimum parameters of this PID controller were obtained using a Particle Swarm Optimization (PSO) algorithm. Bluetooth was used to realize wireless transmissions, and a chaotic wireless communication security system was developed in the design concept of a chaotic communication security system. The experimental results show that this scheme can be used successfully in image encryption.
A Sensing Element Based on a Bent and Elongated Grooved Polymer Optical Fiber
Authors: Lu Wei-Hua , Chen Li-Wen , Xie Wen-Fu , Chen Yung-Chuan
Published: June 2012

An experimental and numerical investigation is performed into the power loss induced in grooved polymer optical fibers (POFs) subjected to combined bending and elongation deformations. The power loss is examined as a function of both the groove depth and the bend radius. An elastic-plastic three-dimensional finite element model is constructed to simulate the deformation in the grooved region of the deformed specimens. The results indicate that the power loss increases significantly with an increasing bending displacement or groove depth. Specifically, the power loss increases to as much as 12% given a groove depth of 1.1 mm and a bending displacement of 10 mm. Based on the experimental results, an empirical expression is formulated to relate the power loss with the bending displacement for a given groove depth. It is shown that the difference between the estimated power loss and the actual power loss is less than 2%.
High-affinity multivalent wheat germ agglutinin ligands by one-pot click reaction
Authors: Beckmann Henning S G , Möller Heiko M , Wittmann Valentin
Published: June 2012

A series of six mono-, di-, and trivalent N,N’-diacetylchitobiose derivatives was conveniently prepared by employing a one-pot procedure for Cu(II)-catalyzed diazo transfer and Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) starting from commercially available amines. These glycoclusters were probed for their binding potencies to the plant lectin wheat germ agglutinin (WGA) from Triticum vulgaris by an enzyme-linked lectin assay (ELLA) employing covalently immobilized N-acetylglucosamine (GlcNAc) as a reference ligand. IC50 values were in the low micromolar/high nanomolar range, depending on the linker between the two disaccharides. Binding enhancements β up to 1000 for the divalent ligands and 2800 for a trivalent WGA ligand, compared to N,N’-diacetylchitobiose as the corresponding monovalent ligand, were observed. Molecular modeling studies, in which the chitobiose moieties were fitted into crystallographically determined binding sites of WGA, correlate the binding enhancements of the multivalent ligands with their ability to bind to the protein in a chelating mode. The best WGA ligand is a trivalent cluster with an IC50 value of 220 nM. Calculated per mol of contained chitobiose, this is the best WGA ligand known so far.
L'interprétation des terrains et le recours à des propositions théoriques
Authors: Demeulenaere Pierre
Published: June 2012

Résumé Dans cet article, nous affirmons que l’ethnographie ne devrait pas être séparée entre travail empirique de terrain et interprétation théorique qui constituerait un moment distinct. L’idée est que toute entreprise ethnographique, qu’elle soit descriptive ou explicative, est basée sur des propositions générales théoriques qui ne sont pas déduites directement du travail de terrain qui est à interpréter. L’article propose une typologie de ces propositions générales et considère leur localisation dans le raisonnement explicatif qui est essentiellement déductif.
Les jurés populaires et les épreuves de la cour d'assises : entre légitimité d'un regard profane et interpellation du pouvoir des juges
Authors: Jellab Aziz , Giglio-Jacquemot Armelle
Published: June 2012

Résumé Citoyens tirés au sort à partir de listes électorales, les jurés de cour d’assises doivent se socialiser assez rapidement à un univers judiciaire et à un rôle auquel ils ne sont guère préparés. Cette socialisation ne va pas de soi, car non seulement les jurés s’interrogent sur leur légitimité puisqu’ils sont rarement des juristes mais aussi, ils découvrent des professionnels du droit, des faits incriminés et des mondes sociaux dont la cruauté les déstabilise alors même qu’ils doivent conserver une neutralité quant à la fonction de juger. La rencontre avec les professionnels de la cour d’assises et plus particulièrement avec les juges est marquée par de nombreuses épreuves et génère des sentiments très ambivalents, tenant aussi bien aux modes d’accueil, de qualification et de disqualification qui leur sont réservés, qu’aux écarts observés entre la légitimité des magistrats professionnels et des pratiques judiciaires perçues comme « manipulatoires ». Si juger n’exige pas de la part des citoyens la connaissance du droit mais une attention et un usage de la « raison » en vue de construire leur « intime conviction », l’émotion qu’ils éprouvent à l’écoute des faits incriminés apparaît aux juges comme à la fois inévitable et susceptible de déstabiliser la sérénité du jugement. Aussi, les rapports de pouvoir qui naissent lors de cette rencontre entre juges professionnels et jurés profanes ne prennent sens qu’à l’aune des contraintes institutionnelles qui s’exercent sur les premiers et des manières dont les seconds pensent plus ou moins peser sur la justice pendant le délibéré. L’appropriation socialement différenciée de son rôle de juré comme les différences relevées chez les magistrats quant à la conduite des procès et à la place accordée aux jurés ne remettent pas en cause le poids dominant des juges mais laissent entrevoir des effets différenciés de cette expérience sur les citoyens-juges. La contestation du pouvoir des juges qui cohabite avec l’attachement des jurés au maintien d’une justice échevine démontre qu’au-delà des épreuves vécues, la socialisation à la cour d’assises est une promesse de démocratie apportant une certaine reconnaissance aux individus.
L'inégalité des chancessur le marché du travail urbain ouest-africain
Authors: Pasquier-Doumer Laure
Published: June 2012

Résumé Cette étude cherche à savoir si l’origine sociale des travailleurs détermine leurs opportunités sur le marché du travail, en comparant le degré d’inégalité des chances sur le marché du travail dans sept capitales ouest-africaines. Elle évalue ensuite pour chacune des villes si la situation professionnelle du père agit directement sur le positionnement sur le marché du travail ou si son effet est indirect, à travers l’éducation. Dans le premier cas, les politiques visant à égaliser les chances doivent agir directement sur le marché du travail, dans le second cas, elles doivent agir en amont, sur le système éducatif. Classification JEL : J24, J62, D63
La demande en eau potable est-elle élastique au prix ? Le cas de la wilaya de Bejaia
Authors: Kertous Mourad
Published: June 2012

Résumé Confrontée à une disponibilité en eau inférieure à 500 m 3 /an/habitant, l’Algérie a longtemps axé sa politique de gestion de l’eau sur l’offre, en visant la mobilisation de nouvelles sources d’approvisionnement. Une telle approche apparaît aujourd’hui insuffisante, et doit être combinée avec une meilleure connaissance de la maîtrise de la demande. Notre approche dans cet article consiste donc à appréhender la gestion de l’eau en Algérie du côté de la demande. La stratégie suivie consiste à estimer une fonction de demande d’eau potable sur un échantillon de ménages au niveau de la wilaya de Bejaia. Parmi les résultats marquants de notre recherche figure la faible réaction des abonnés face aux changements des prix. Une augmentation du prix de l’eau de 1 % n’induit qu’une réduction de 0,42 % de la demande. Notre travail établit également que la politique de rationnement horaire encourage la surconsommation. Classification JEL : L95, Q25, D12
Residual Neuromuscular Blockade in Critical Care
Authors: Wilson Jason , Collins Angela S. , Rowan Brea O.
Published: June 2012

Neuromuscular blockade is a pharmacological adjunct for anesthesia and for surgical interventions. Neuromuscular blockers can facilitate ease of instrumentation and reduce complications associated with intubation. An undesirable sequela of these agents is residual neuromuscular blockade. Residual neuromuscular blockade is linked to aspiration, diminished response to hypoxia, and obstruction of the upper airway that may occur soon after extubation. If an operation is particularly complex or requires a long anesthesia time, residual neuromuscular blockade can contribute to longer stays in the intensive care unit and more hours of mechanical ventilation. Given the risks of this medication class, it is essential to have an understanding of the mechanism of action of, assessment of, and factors affecting blockade and to be able to identify factors that affect pharmacokinetics.
Withdrawal of Life-Sustaining Treatment
Authors: Stacy Kathleen M.
Published: June 2012

Withdrawal of life support is an option for patients with prolonged mechanical ventilation when all attempts at weaning have failed and it is deemed futile to continue the therapy, when quality of life is unacceptable, or when it is perceived that the patient is suffering. The purpose of this article is to present the nursing aspects of managing an adult patient undergoing the withdrawal of mechanical ventilation as an end-of-life procedure. Withdrawal of mechanical ventilation is a complex and difficult process that requires meticulous planning and management. Conferences with the patient and the patient’s family are critical to addressing emotional support and ensuring that everyone understands the process and is provided an opportunity to gather information. Clear communication with patients and their families can ensure that the process goes smoothly. Having an organized approach can ensure that patients experience a peaceful death and staff experience closure regarding the event.
Teaching Strategies to Support Evidence-Based Practice
Authors: Winters Charlene A. , Echeverri Rebecca
Published: June 2012

Evidence-based practice is an expected core competency of all health care clinicians regardless of discipline. Use of evidence-based practice means integrating the best research with clinical expertise and patient values to achieve optimal health outcomes. Evidence-based practice requires nurses to access and appraise evidence rapidly before integrating it into clinical practice. Role modeling and integrating the skills necessary to develop evidence-based practice into clinical and nonclinical courses is an important part in developing positive attitudes toward evidence-based practice, an essential first step to using evidence to guide practice decisions. The step-by-step approach to evidence-based practice proposed by Melnyk and colleagues provides an excellent organizing framework for teaching strategies specifically designed to facilitate nurses’ knowledge and skill development in evidence-based practice.
Hyponatremia Caused by Polydipsia
Authors: Chamberlain Lyne
Published: June 2012

Hyponatremia (serum sodium <135 mEq/L) is the most common electrolyte disorder. The severity of symptoms is related to how rapidly the condition develops and the degree of cerebral edema that results from the low serum level of sodium. Hypertonic saline and the new vasopressin receptor antagonists are highly effective treatments for severe symptomatic hyponatremia, yet they can result in severe neurological complications if sodium levels are restored too quickly. Hyponatremia is classified as hypovolemic, euvolemic, and hypervolemic. Treatments include administration of high-risk medications and fluid restriction to restore fluid and electrolyte balance and relieve cerebral effects. Nursing care to ensure safe outcomes involves multidisciplinary collaboration, close monitoring of serum sodium levels and intake and output, and assessment for neurological changes.
Engaging Families to Participate in Care of Older Critical Care Patients
Authors: Hardin Sonya R.
Published: June 2012

Provision of optimal outcomes for older adults can be understood through the use of the American Association for Critical-Care Nurses Synergy Model. These outcomes can be enhanced if strategies are designed to improve the characteristics of patients and families as described in the Synergy Model. When older adults are admitted to critical care units, spouses, children, and friends are in a position to participate in care. This column examines the Synergy Model’s patient characteristic of participation in care relative to involvement of the family and significant others of the older patient as a method of enhancing optimal outcomes.