bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal changes in intracranial pressure in a modified experimental model of closed head injury
Authors: Engelborghs Koen , Verlooy Jan , Van Reempts Jos , Van Deuren Bruno , Van de Ven Mies , Borgers Marcel
Published: June 2009

Object. The authors describe an experimental model of closed head injury in rodents that was modified from one developed by Marmarou and colleagues. This modification allows dual control of the dynamic process of impact compared with impulse loading that occurs at the moment of primary brain injury. The principal element in this weight-drop model is an adjustable table that supports the rat at the moment of impact from weights positioned at different heights (accelerations). The aim was to obtain reproducible pathological intracranial pressure (ICPs) while maximally reducing the incidence of mortality and skull fractures.

Methods. Intracranial pressure was investigated in different experimental settings, including two different rat strains and various impact-acceleration conditions and posttrauma survival times. Identical impact-acceleration injuries produced a considerably higher mortality rate in Wistar rats than in Sprague—Dawley rats (50% and 0%, respectively). Gradually increasing severity of impact-acceleration conditions resulted in findings of a significant correlation between the degree of traumatic challenge and increased ICP at 4 hours (p < 0.001, R2 = 0.73). When the impact-acceleration ratio was changed to result in a more severe head injury, the ICP at 4, 24, and 72 hours was significantly elevated in comparison with that seen in sham-injured rats (4 hours: 19.7 ± 2.8 mm Hg, p = 0.004; 24 hours: 21.8 ± 1.1 mm Hg, p = 0.002; 72 hours: 11.9 ± 2.5 mm Hg, p = 0.009). Comparison of the rise in ICP between moderate and severe impact-acceleration injury at 4 and 24 hours revealed a significantly higher value after severe injury (4 hours: p = 0.008; 24 hours: p = 0.004). Continuous recordings showed that ICP mounted very rapidly to peak values, which declined gradually toward a pathological level dependent on the severity of the primary insult. Histological examination after severe trauma revealed evidence of irreversible neuronal necrosis, diffuse axonal injury, petechial bleeding, glial swelling, and perivascular edema.

Conclusions. This modified closed head injury model mimics several clinical features of traumatic injury and produces reliable, predictable, and reproducible ICP elevations with concomitant morphological alterations.
Role of nitric oxide in traumatic brain injury in the rat
Authors: Wada Kojiro , Chatzipanteli Katina , Busto Raul , Dietrich W. Dalton
Published: June 2009

Object.Although nitric oxide (NO) has been shown to play an important role in the pathophysiological process of cerebral ischemia, its contribution to the pathogenesis of traumatic brain injury (TBI) remains to be clarified. The authors investigated alterations in constitutive nitric oxide synthase (NOS) activity after TBI and the histopathological response to pharmacological manipulations of NO.

Methods.Male Sprague—Dawley rats underwent moderate (1.7–2.2 atm) parasagittal fluid-percussion brain injury. Constitutive NOS activity significantly increased within the ipsilateral parietal cerebral cortex, which is the site of histopathological vulnerability, 5 minutes after TBI occurred (234.5 ± 60.2% of contralateral value [mean ± standard error of the mean {SEM}], p < 0.05), returned to control values by 30 minutes (114.1 ± 17.4%), and was reduced at 1 day after TBI (50.5 ± 13.1%, p < 0.01). The reduction in constitutive NOS activity remained for up to 7 days after TBI (31.8 ± 6.0% at 3 days, p < 0.05; 20.1 ± 12.7% at 7 days, p < 0.01). Pretreatment with 3-bromo-7-nitroindazole (7-NI ) (25 mg/kg), a relatively specific inhibitor of neuronal NOS, significantly decreased contusion volume (1.27 ± 0.17 mm3[mean ± SEM], p < 0.05) compared with that of control (2.52 ± 0.35 mm3). However, posttreatment with 7-NI or pre- or posttreatment with nitro-l-arginine-methyl ester (l-NAME) (15 mg/kg), a nonspecific inhibitor of NOS, did not affect the contusion volume compared with that of control animals (1.87 ± 0.46 mm3, 2.13 ± 0.43 mm3, and 2.18 ± 0.53 mm3, respectively). Posttreatment withl-arginine (1.1 ± 0.3 mm3, p < 0.05), but not 3-morpholino-sydnonimine (SIN-1) (2.48 ± 0.37 mm3), significantly reduced the contusion volume compared with that of control animals.

Conclusions.These data indicate that constitutive NOS activity is affected after moderate parasagittal fluid percussion brain injury in a time-dependent manner. Inhibition of activated neuronal NOS and/or enhanced endothelial NOS activation may represent a potential therapeutic strategy for the treatment of TBI.
Tardy sciatic nerve palsy following apophyseal avulsion fracture of the ischial tuberosity
Authors: Spinner Robert J. , Atkinson John L. D. , Wenger Doris E. , Stuart Michael J.
Published: June 2009

✓ This 41-year-old man presented with a 2-year history of symptoms and signs of sciatic nerve compression. Imaging studies revealed a large ossified fragment within the biceps muscle of the thigh abutting the sciatic nerve at the level of the lesser trochanter. The bony fragment resulted from an unrecognized apophyseal avulsion fracture of the ischial tuberosity, which the patient had sustained while sprinting 27 years earlier.

External neurolysis of the sciatic nerve and excision of the mass led to a successful outcome.
Intradural spinal teratoma: evidence for a dysembryogenic origin
Authors: Koen Joseph L. , McLendon Roger E. , George Timothy M.
Published: June 2009

✓ Intradural spinal teratoma is a rare tumor that can be associated with dysraphic defects. Although the origin of these tumors is traditionally thought to be secondary to primordial germ cells misplaced early in embryogenesis, the pathogenesis of intraspinal teratoma remains unclear. The authors present a series of patients in whom an intradural teratoma arose at the same site as a developmental spinal cord abnormality, including a split cord malformation, myelomeningocele, and lipomyelomeningocele. It is postulated that these lesions were the result of a dysembryogenic mechanism and were not neoplastic.
Magnetic resonance imaging—compatible posterior cervical implant for occipitocervical stabilization
Authors: Crockard H. Alan , Tammam Ahmed , Mendoza Nigel
Published: June 2009

✓ Posterior cervical stabilization was accomplished in 30 patients (19 females and 11 males) by using sublaminar titanium cables and a new titanium bullet-shaped implant. Seventeen patients underwent occipitocervical fixation and 13 others were treated subaxially. These patients have been followed for 18 to 52 months (mean 36 months), and no implant has failed during the follow-up period.
Use of the GDC crescent for embolization of tumors fed by cavernous and petrous branches of the internal carotid artery
Authors: Guglielmi Guido
Published: June 2009

✓ This report presents two cases of hypervascular tumor in which the cavernous and petrous internal carotid artery feeding vessels were successfully occluded using a new endovascular device, the crescent-shaped platinum Guglielmi detachable coil (GDC). With this new embolic agent the risk of unwanted embolization of normal intracranial arteries was significantly reduced. The GDC “crescent” seems particularly useful when distal, superselective, and controllable occlusion of small arterial feeding vessels is the goal of the treatment.
Irving S. Cooper (1922–1985): a pioneer in functional neurosurgery
Authors: Das Kaushik , Benzil Deborah L. , Rovit Richard L. , Murali Raj , Couldwell William T.
Published: June 2009

✓ Irving S. Cooper (1922–1985), the son of a salesman, worked his way through high school, college, and medical school to become one of the pioneers in functional neurosurgery. He developed several novel techniques for the surgical management of Parkinson's disease and other crippling movement disorders. A keen interest in the physiology of movement disorders was kindled by his doctoral research and continued during his neurosurgical training. He began to apply this knowledge to surgical practice in 1952 when he began his faculty career as Assistant Professor of Surgery at New York University. At the time, surgical treatment of parkinsonian tremor focused on various techniques used to interrupt the pyramidal tract. During a subtemporal approach for a cerebral pedunculotomy, he inadvertently injured and, subsequently, was forced to occlude the anterior choroidal artery. Much to Cooper's surprise, following emergence from anesthesia the patient's tremor and rigidity were abolished without any residual hemiparesis. This serendipitous observation, together with Meyer's earlier work on the role of the basal ganglia in motor control, helped focus surgical efforts on targets within the basal ganglia and, subsequently, within the thalamus to alleviate the movement disorders associated with Parkinson's disease. While at New York University, Cooper developed chemopallidectomy and, later at St. Barnabas Hospital in the Bronx (1954–1977), he used cryothalamectomy as a surgical technique for primary control of tremor in patients with Parkinson's disease. Cooper authored many original papers on surgical techniques and several textbooks on the lives of patients afflicted with Parkinson's disease and other crippling movement disorders. Although considered controversial, this fascinating and complex neurosurgeon made significant contributions to this field.
Leonardo da Vinci: the search for the soul
Authors: Del Maestro Rolando F.
Published: June 2009

✓ The human race has always contemplated the question of the anatomical location of the soul. During the Renaissance the controversy crystallized into those individuals who supported the heart (“cardiocentric soul”) and others who supported the brain (“cephalocentric soul”) as the abode for this elusive entity. Leonardo da Vinci (1452–1519) joined a long list of other explorers in the “search for the soul.” The method he used to resolve this anatomical problem involved the accumulation of information from ancient and contemporary sources, careful notetaking, discussions with acknowledged experts, and his own personal search for the truth. Leonardo used a myriad of innovative methods acquired from his knowledge of painting, sculpture, and architecture to define more clearly the site of the “senso comune”—the soul. In this review the author examines the sources of this ancient question, the knowledge base tapped by Leonardo for his personal search for the soul, and the views of key individuals who followed him.
Pterional craniotomy via a transcavernous approach for the treatment of low-lying distal basilar artery aneurysms
Authors: Nutik Stephen L.
Published: June 2009

Object. The author describes a surgical procedure in which pterional craniotomy is performed via a transcavernous approach to treat low-lying distal basilar artery (BA) aneurysms. This intradural procedure is compared with the extradural procedure described by Dolenc, et al.

Methods. The addition of a transcavernous exposure to the standard pterional intradural transsylvian approach allows a lower exposure of the distal BA behind the dorsum sellae. The technical steps involved in this procedure are as follows: 1) removal of the anterior clinoid process: 2) entry into the cavernous sinus medial to the third nerve; 3) packing of the venous channels of the cavernous sinus lying between the carotid artery and the pituitary gland to open this space; 4) removal of the posterior clinoid process and the portion of the dorsum sellae that is exposed from within the cavernous sinus; and 5) removal of the exposed dura mater to obtain additional exposure of the perimesencephalic cistern. Eight cases of aneurysms of the distal BA are presented to illustrate how this approach can help in their surgical treatment.

Conclusions. Using the standard pterional approach, these distal BA aneurysms were found to be either too low relative to the posterior clinoid process for adequate exposure or there was insufficient room for temporary clipping of the BA proximal to the lesion. The addition of a transcavernous exposure eliminated these technical problems and aneurysm clipping could be accomplished in each case.
Radiotherapy for nonfunctional pituitary adenoma: analysis of long-term tumor control
Authors: Breen Patrick , Flickinger John C. , Kondziolka Douglas , Martinez Augusto J.
Published: June 2009

Object.The authors studied outcomes in patients who had undergone radiotherapy for nonfunctional pituitary adenoma to assess long-term tumor control and to identify factors affecting tumor control such as higher radiation doses, improved imaging, and histological characteristics of the tumor.

Methods.In this retrospective study, the authors evaluated 120 patients who received radiotherapy for nonfunctional pituitary adenomas between 1960 and 1991. The median follow-up period was 9 years (range 1 month–32 years). Radiation doses varied between 37.6 and 65.6 Gy (median 46.7 Gy).

Tumors progressed in 15 of the 120 patients by 1 to 25 years after radiotherapy. Actuarial tumor control rates at 10, 20, and 30 years were 87.5 ± 3.6%, 77.6 ± 6.3%, and 64.7 ± 12.9%, respectively. Tumor progression after radiotherapy occurred significantly more often (p = 0.0397) in patients with oncocytoma than in patients with nononcocytic null cell adenoma. No other factors correlated significantly with tumor control. One case of optic and oculomotor neuropathy developed 4.5 years after a maximum dose of 50 Gy in 25 fractions. Radiation-induced neoplasms (meningioma and glioblastoma multiforme) developed at a rate of 2.7% at 10 and 30 years.

Conclusions.The oncocytic variant of null cell pituitary adenoma appears less sensitive to control by radiotherapy than nononcocytic undifferentiated cell adenoma. A follow-up period extending beyond 20 years is needed adequately to assess the efficacy of radiotherapy for tumor control. Doses of 40 or 45 Gy in 20 or 25 fractions, respectively, appear optimal.
Vestibular schwannoma management
Authors: Pollock Bruce E. , Lunsford L. Dade , Kondziolka Douglas , Sekula Raymond , Subach Brian R. , Foote Robert L. , Flickinger John C.
Published: June 2009

Object. The indications, operative findings, and outcomes of vestibular schwannoma microsurgery are controversial when it is performed after stereotactic radiosurgery. To address these issues, the authors reviewed the experience at two academic medical centers.

Methods. During a 10-year interval, 452 patients with unilateral vestibular schwannomas underwent gamma knife radiosurgery. Thirteen patients (2.9%) underwent delayed microsurgery at a median of 27 months (range 7–72 months) after they had undergone radiosurgery. Six of the 13 patients had undergone one or more microsurgical procedures before they underwent radiosurgery. The indications for surgery were tumor enlargement with stable symptoms in five patients, tumor enlargement with new or increased symptoms in five patients, and increased symptoms without evidence of tumor growth in three patients. Gross-total resection was achieved in seven patients and near-gross-total resection in four patients. The surgery was described as more difficult than that typically performed for schwannoma in eight patients, no different in four patients, and easier in one patient. At the last follow-up evaluation, three patients had normal or near-normal facial function, three patients had moderate facial dysfunction, and seven had facial palsies. Three patients were incapable of caring for themselves, and one patient died of progression of a malignant triton tumor.

Conclusions. Failed radiosurgery in cases of vestibular schwannoma was rare. No clear relationship was demonstrated between the use of radiosurgery and the subsequent ease or difficulty of delayed microsurgery. Because some patients have temporary enlargement of their tumor after radiosurgery, the need for surgical resection after radiosurgery should be reviewed with the neurosurgeon who performed the radiosurgery and should be delayed until sustained tumor growth is confirmed. A subtotal tumor resection should be considered for patients who require surgical resection of their tumor after vestibular schwannoma radiosurgery.
Unruptured aneurysms presenting with mass effect sypmtoms: response to endosaccular treatment with Guglielmi detachable coils.
Authors: Malisch Tim W. , Guglielmi Guido , Viñuela Fernando , Duckwiler Gary , Gobin Y. Pierre , Martin Neil A. , Frazee John G. , Chmiel Joan S.
Published: June 2009

Object. Embolization of intracranial aneurysms by using Guglielmi detachable coils (GDCs) is proving to be a safe method of protecting aneurysms from rupture. Occasionally, patients with unruptured intracranial aneurysms present with symptoms related to the aneurysm's mass effect on either the brain parenchyma or cranial nerves. In the present study, the authors conducted a retrospective review to evaluate the response to GDC embolization in a series of 19 patients presenting with cranial nerve dysfunction due to mass effect.

Methods. Aneurysms were classified by size, shape, wall calcification, and amount of intraluminal thrombus. Patients were classified by duration of symptoms prior to GDC treatment (range < 1 month to > 10 years). Clinical assessment was performed within days of the GDC procedure and at later follow-up appointments (range 1–70 months, mean 24 months).

In the immediate post-GDC period, four patients experienced worsening of cranial nerve deficits. Two of the four patients had transient worsening of visual acuity, which later improved to better than baseline status. Another patient who had presented with headache and seventh and eighth cranial nerve deficits from a vertebrobasilar junction aneurysm had improvement in these symptoms, but developed a new diplopia. The fourth patient had worsening of her visual acuity, which had not resolved at the 1-month follow-up examination; this patient later underwent surgical decompression.

Conclusions. On late follow-up review, the response was classified as complete resolution of symptoms in six patients (32%), improvement in eight patients (42%), no significant change in four patients (21%), and symptom worsening in one patient (5%). Patients with smaller aneurysms and those with shorter pretreatment duration of symptoms were more likely to experience an improvement in their symptoms following GDC treatment, although statistical significance was not reached in this series (p = 0.603 and p = 0.111, respectively). The presence of aneurysmal wall calcification (six patients) or intraluminal thrombus (12 patients) showed no correlation with the response of mass effect symptoms in these patients.
Preoperative predictors of anterior temporal language areas
Authors: Schwartz Theodore H. , Devinsky Orrin , Doyle Werner , Perrine Kenneth
Published: June 2009

Object. Although it is known that 5 to 10% of patients have language areas anterior to the rolandic cortex, many surgeons still perform standard anterior temporal lobectomies for epilepsy of mesial onset and report minimal long-term dysphasia. The authors examined the importance of language mapping before anterior temporal lobectomy.

Methods. The authors mapped naming, reading, and speech arrest in a series of 67 patients via stimulation of long-term implanted subdural grids before resective epilepsy surgery and correlated the presence of language areas in the anterior temporal lobe with preoperative demographic and neuropsychometric data.

Naming (p < 0.03) and reading (p < 0.05) errors were more common than speech arrest in patients undergoing surgery in the anterior temporal lobe. In the approximate region of a standard anterior temporal lobectomy, including 2.5 cm of the superior temporal gyrus and 4.5 cm of both the middle and inferior temporal gyrus, the authors identified language areas in 14.5% of patients tested. Between 1.5 and 3.5 cm from the temporal tip, patients who had seizure onset before 6 years of age had more naming (p < 0.02) and reading (p < 0.01) areas than those in whom seizure onset occurred after age 6 years. Patients with a verbal intelligence quotient (IQ) lower than 90 had more naming (p < 0.05) and reading (p < 0.02) areas than those with an IQ higher than 90. Finally, patients who were either left handed or right hemisphere memory dominant had more naming (p < 0.05) and reading (p < 0.02) areas than right-handed patients with bilateral or left hemisphere memory lateralization. Postoperative neuropsychometric testing showed a trend toward a greater decline in naming ability in patients who were least likely to have anterior language areas, that is, those with higher verbal IQ and later seizure onset.

Conclusions. Preoperative identification of markers of left hemisphere damage, such as early seizure onset, poor verbal IQ, left handedness, and right hemisphere memory dominance should alert neurosurgeons to the possibility of encountering essential language areas in the anterior temporal lobe (1.5–3.5 cm from the temporal tip). Naming and reading tasks are required to identify these areas. Whether removal of these areas necessarily induces long-term impairment in verbal abilities is unknown; however, in patients with a low verbal IQ and early seizure onset, these areas appear to be less critical for language processing.
Role of glial fibrillary acidic protein expression in the biology of human glioblastoma U-373MG cells
Authors: Murphy Katrina G. , Hatton James D. , Sang U Hoi
Published: June 2009

Object. The relationship between glial fibrillary acidic protein (GFAP) expression and glial tumor cell behavior has not been well defined. The goal of this study was to examine this relationship further.

Methods. To investigate the relationship between GFAP expression and glial tumor cell behavior, the authors isolated clones from the human glioblastoma cell line, U-373MG, according to their level of GFAP expression. Immunochemical analysis demonstrated that one clone had consistently low GFAP expression (approximately 93% of cells were GFAP negative), whereas a second clone had consistently high GFAP expression (approximately 80% of the cells were GFAP positive). The structure, population doubling time, saturation density, anchorage-independent growth, migratory rate, and invasive potential of these two clones were determined in relation to their level of GFAP expression. Morphologically, both clones were composed of ameboid as well as stellate components. Although the population doubling times of the two clones were equally rapid, the clone with low GFAP expression demonstrated a slightly higher saturation density compared with the clone with high GFAP expression. In an anchorage-independent environment (soft agar), a greater difference in growth characteristics was noted between the two clones: the high-expression clone formed more colonies and these colonies were compact, well defined, and spherical, whereas the low-expression clone formed predominantly smaller, two-dimensional colonies with vague boundaries and isolated cells or groups of cells at the periphery. In contrast to these minor differences between the clones, the low-expression clone showed a markedly increased migratory rate and invasive potential compared with the high-expression clone. Therefore, the clone with reduced GFAP expression appeared more aggressive, demonstrating decreased contact inhibition, increased migratory rate, and increased invasive potential.

Conclusions. These results suggest a direct correlation between GFAP expression and some measures of aggressive tumor growth and transformation properties.
Relationships of the cisternal segment of the trochlear nerve
Authors: Tubbs R. Shane , Oakes W. Jerry
Published: June 2009

Object. The cisternal portion of the trochlear nerve (fourth cranial nerve) can easily be injured during intracranial surgical operations. To help minimize the chance of such injury by promoting a thorough understanding of the anatomy of this nerve and its relationships to surrounding structures, the authors present this anatomical study.

Methods. In this study, in which 12 cadaveric heads (24 sides) were used, the authors describe exact distances between the trochlear nerve and various surrounding structures. Also described are relatively safe areas in which to manipulate or enter the tentorium, and these are referenced to external landmarks.

Conclusions. This information will prove useful in planning and executing surgical procedures in and around the free edge of the tentorium cerebelli.
Frontoorbital advancement by gradual distraction
Authors: Hirabayashi Shinichi , Sugawara Yasushi , Sakurai Atsushi , Harii Kiyonori , Park Susam
Published: June 2009

✓ A substantial number of patients with coronal synostosis who undergo frontoorbital advancement still require additional surgical treatment to correct increased intracranial pressure or unsatisfactory craniofacial structure. However, frontoorbital advancement currently requires elevation of the frontal as well as the orbital bone, which can result in a fragile dura mater and partial resorption of the advanced bone. Thus the dura is easily torn by dissection and the advanced bone is further resorbed and deformed during repeated craniofacial operations. To avoid these drawbacks and to create an easier second surgical treatment via the intracranial approach, a new technique for frontoorbital advancement is presented. In this technique frontoorbital bone is advanced as a single unit, without elevation from the underlying dura, by means of gradual distraction. The details of the technique and an illustrative case are reported.
Endoscopic treatment of colloid cysts of the third ventricle
Authors: Abdou M. Samy , Cohen Alan R.
Published: June 2009

✓ The surgical technique for the endoscopic evacuation of colloid cysts of the third ventricle in 13 patients is described. The authors conclude that endoscopic resection of these lesions is a useful addition to the current surgical repertoire and a viable alternative to stereotactic aspiration or open craniotomy.
Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System
Authors: Fujioka Kouki , Futamura Yasuhiro , Shiohara Tomoo , Hoshino Akiyoshi , Kanaya Fumihide , Manome Yoshinobu , Yamamoto Kenji
Published: June 2009

Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin.
Role of Lifshitz Invariants in Liquid Crystals
Authors: Sparavigna Amelia
Published: June 2009

The interaction between an external action and the order parameter, via a dependence described by a so-called Lifshitz invariant, is very important to determine the final configuration of liquid crystal cells. The external action can be an electric field applied to the bulk or the confinement due to free surfaces or cell walls. The Lifshitz invariant includes the order parameter in the form of an elastic strain. This coupling between elastic strains and fields, inserted in a Landau-Ginzburg formalism, is well known and gives rise to striction effects causing undulations in the director configuration. We want to discuss here the role of Lifshitz coupling terms, following an approach similar to that introduced by Dzyaloshinskii for magnetic materials. Case studies on nematics in planar and cylindrical cells are also proposed.
New Azaphilones, Seco-Chaetomugilins A and D, Produced by a Marine-Fish-Derived Chaetomium globosum
Authors: Yamada Takeshi , Muroga Yasuhide , Tanaka Reiko
Published: June 2009

Seco-chaetomugilins A and D were isolated from a strain of Chaetomium globosum that was originally isolated from the marine fish Mugil cephalus, and their absolute stereostructures were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR techniques, along with the chemical transformation from known chaetomugilins A and D. Seco-chaetomugilin D exhibited growth inhibitory activity against cultured P388, HL-60, L1210, and KB cells.
Extraction with SPME and Synthesis of 2-Methyl-6-vinylpyrazine by a ‘One Pot’ Reaction Using Microwaves
Authors: Robledo Norma , Escalante Jaime , Arzuffi René
Published: June 2009

A synthesis of 2-methyl-6-vinylpyrazine was carried out by way of a ‘one pot’ reaction. In order to establish the efficiency of this synthesis the extraction of the volatiles released by male papaya fruit flies was performed by SPME (solid phase micro-extraction). The compound was separated and identified using GC/MSD (gas chromatography/mass spectrometry detector).
Effect of Extraction Solvent/Technique on the Antioxidant Activity of Selected Medicinal Plant Extracts
Authors: Sultana Bushra , Anwar Farooq , Ashraf Muhammad
Published: June 2009

Theeffects of four extracting solvents [absolute ethanol, absolute methanol, aqueous ethanol (ethanol: water, 80:20 v/v) and aqueous methanol (methanol: water, 80:20 v/v)] and two extraction techniques (shaking and reflux) on the antioxidant activity of extracts of barks of Azadirachta indica, Acacia nilotica, Eugenia jambolana, Terminalia arjuna, leaves and roots of Moringa oleifera, fruit of Ficus religiosa,and leaves of Aloe barbadensis were investigated. The tested plant materials contained appreciable amounts of total phenolic contents (0.31-16.5 g GAE /100g DW), total flavonoid (2.63-8.66 g CE/100g DW); reducing power at 10 mg/mL extract concentration (1.36-2.91), DPPH. scavenging capacity (37.2-86.6%), and percent inhibition of linoleic acid (66.0-90.6%). Generally higher extract yields, phenolic contents and plant material antioxidant activity were obtained using aqueous organic solvents, as compared to the respective absolute organic solvents. Although higher extract yields were obtained by the refluxing extraction technique, in general higher amounts of total phenolic contents and better antioxidant activity were found in the extracts prepared using a shaker.
A High Resolution Color Image Restoration Algorithm for Thin TOMBO Imaging Systems
Authors: El-Sallam Amar A. , Boussaid Farid
Published: June 2009

In this paper, we present a blind image restoration algorithm to reconstruct a high resolution (HR) color image from multiple, low resolution (LR), degraded and noisy images captured by thin (< 1mm) TOMBO imaging systems. The proposed algorithm is an extension of our grayscale algorithm reported in [1] to the case of color images. In this color extension, each Point Spread Function (PSF) of each captured image is assumed to be different from one color component to another and from one imaging unit to the other. For the task of image restoration, we use all spectral information in each captured image to restore each output pixel in the reconstructed HR image, i.e., we use the most efficient global category of point operations. First, the composite RGB color components of each captured image are extracted. A blind estimation technique is then applied to estimate the spectra of each color component and its associated blurring PSF. The estimation process is formed in a way that minimizes significantly the interchannel cross-correlations and additive noise. The estimated PSFs together with advanced interpolation techniques are then combined to compensate for blur and reconstruct a HR color image of the original scene. Finally, a histogram normalization process adjusts the balance between image color components, brightness and contrast. Simulated and experimental results reveal that the proposed algorithm is capable of restoring HR color images from degraded, LR and noisy observations even at low Signal-to-Noise Energy ratios (SNERs). The proposed algorithm uses FFT and only two fundamental image restoration constraints, making it suitable for silicon integration with the TOMBO imager.
High Resolution Remote Sensing of Densely Urbanised Regions: a Case Study of Hong Kong
Authors: Nichol Janet  E. , Wong Man Sing
Published: June 2009

Data on the urban environment such as climate or air quality is usually collected at a few point monitoring stations distributed over a city. However, the synoptic viewpoint of satellites where a whole city is visible on a single image permits the collection of spatially comprehensive data at city-wide scale. In spite of rapid developments in remote sensing systems, deficiencies in image resolution and algorithm development still exist for applications such as air quality monitoring and urban heat island analysis. This paper describes state-of-the-art techniques for enhancing and maximising the spatial detail available from satellite images, and demonstrates their applications to the densely urbanised environment of Hong Kong. An Emissivity Modulation technique for spatial enhancement of thermal satellite images permits modelling of urban microclimate in combination with other urban structural parameters at local scale. For air quality monitoring, a Minimum Reflectance Technique (MRT) has been developed for MODIS 500 m images. The techniques described can promote the routine utilization of remotely sensed images for environmental monitoring in cities of the 21st century.
A Review of Wireless Sensor Technologies and Applications in Agriculture and Food Industry: State of the Art and Current Trends
Authors: Ruiz-Garcia Luis , Lunadei Loredana , Barreiro Pilar , Robla Ignacio
Published: June 2009

The aim of the present paper is to review the technical and scientific state of the art of wireless sensor technologies and standards for wireless communications in the Agri-Food sector. These technologies are very promising in several fields such as environmental monitoring, precision agriculture, cold chain control or traceability. The paper focuses on WSN (Wireless Sensor Networks) and RFID (Radio Frequency Identification), presenting the different systems available, recent developments and examples of applications, including ZigBee based WSN and passive, semi-passive and active RFID. Future trends of wireless communications in agriculture and food industry are also discussed.
A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions
Authors: Debeaux Marc , Brandhorst Kai , Jones Peter G , Hopf Henning , Grunenberg Jörg , Kowalsky Wolfgang , Johannes Hans-Hermann
Published: June 2009

Treatment of benzanthrone (1) with biphenyl-2-yl lithium leads to the surprisingly stable enol 4, which is converted by dehydrogenation into the benzanthrone derivative 7. Under acidic conditions 4 isomerises to the spiro compound 11 and the bicyclo[4.3.1]decane derivative 12. Furthermore, the formation of 7 and the hydrogenated compound 13 is observed. A mechanism for the formation of the reaction products is proposed and supported by DFT calculations.
MODERN BUILDING MATERIALS AND THEIR INVESTIGATION METHODS
Authors: Gailius Albinas , Kinuthia John
Published: June 2009

„Modern building materials and their investigation methods" Journal of Civil Engineering and Management, 15(2), p. 129-130
CONSISTENCY OF FLY ASH AND METAKAOLIN CONCRETE
Authors: Bai Jiping , Gailius Albinas
Published: June 2009

As high‐performance Portland cement (PC), fly ash (FA) and metakaolin (MK) concrete have been developed in wide applications, it has growing interest in optimizing and predicting consistency of fresh PC‐FA‐MK concrete for efficient and practical design and construction. This paper presents statistical models for predicting the consistency of concrete incorporating PC, FA and MK from the experimental results of standard consistency tests. They reflect the effect of variations of pozzolanic replacement materials including FA and MK at graduated replacement levels of up to 40% and 15%, respectively. The predictions produced are compared with the experimental results of consistency of concrete blends. Models show that they can be used to predict the consistency parameters including slump, compacting factor and Vebe time with a good degree of accuracy in a wide range of FA‐MK blends. Design guidelines for evaluating consistency parameters are tentatively recommended along with their confidence intervals for prediction limits at 5% significance levels.

Santrauka

Straipsnyje aprašyti cementbetonio mišinio su lakiaisiais pelenais ir metakaolinu konsistencijos (slankumo, sutankinamumo, Vebe rodiklio) tyrimai. Parenkant betono mišinių sudėtis buvo naudojami lakieji pelenai, kurie pakeisdavo iki 40 % portlandcemenčio ir metakaolinas, kurio buvo dedama iki 15 % cemento masės. Atitinkamai buvo keičiami ir portlandcemenčio kiekiai. Remiantis tyrimų rezultatais, pasiūlyti statistiniai modeliai įvairių sudėčių betono mišinio konsistencijai prognozuoti. Palyginus prognozuojamus ir eksperimentinių tyrimų betono mišinio konsistencijos rodiklius nustatyta, kad jie labai gerai koreliuoja. Todėl pasiūlytus statistinius prognozavimo modelius galima taikyti betonų technologijos praktikoje.
AIR-ENTRAINMENT PROBLEM IN SELF-COMPACTING CONCRETE
Authors: Szwabowski Janusz , Łaźniewska-Piekarczyk Beata
Published: June 2009

According to the actual state of knowledge and in accordance with the PN‐EN 2006–1 norm, it is recommended to use air‐entrainment as a basic way of assuring frost‐resistance of concrete. In case of self‐compacting concrete (SCC), achieving adequate air‐entrainment is a problematic issue because of one of the side‐effects of the functioning of a new generation of superplasticizers, i.e. excessive air‐entrainment (considerably higher than 2%) in a self‐compacting concrete mix. Thus, in this situation, the dosage of an air‐entraining admixture has to be reduced. It was discovered that the cause of an air‐entrainment effect of superplasticizers is a decrease of the surface tension value of the liquid phase in paste. In the paper, the problem of air‐entrainment is discussed, formed as a result of the functioning of a superplasticizer on the characteristics both of concrete and a mixture, depending on the content. To verify the influence a superplasticizer and an air‐entraining admixture have on concrete porosity structure parameters, concrete samples were tested during 300 cycles of freezing and testing the porosity structure according to PN‐EN 480–11. The tests of the structure show that air pores, depending on the level of mix flowability, can be regular and similar in shape and size to pores formed as a result of air‐entrainment admixture action. According to the actual state of knowledge on concrete technology, concrete is frost‐resistant if the value of porosity structure parameter stays within precisely set limits. The results of concrete testing have shown that the parameters of porosity structure do not stay within the precisely set limits, but self‐compacting concrete gets frost‐resistance F300 according to PN‐88/B‐06250. Issues connected with this fact are the subject of this paper.

Santrauka

Laikoma, kad betono atsparumą šalčio poveikiui galima užtikrinti naudojant orą įsiurbiančius priedus. Savaime susitankinančio betono orą įsiurbiančių priedų taikymas ypač painus, nes šiuo atveju galima naudoti tik naujos kartos plastiklius, kurie pasižymi didesniu oro įsiurbimu – >2 %. Norint įvertinti superplastiklių ir orą įsiurbiančių priedų įtaką betono porėtosios struktūros parametrams, buvo ištirta betono bandinių po 300 šaldymo ciklų struktūra pagal PN-EN 480-11 normų reikalavimus. Tyrimų rezultatai parodė, kad nors porėtosios struktūros parametrai nevisiškai atitinka reikalavimus, savaime sutankėjantis betonas pagal PN-88/B-06250 reikalavimus yra F300 klasės. Būtent šis klausimas išsamiai nagrinėjamas straipsnyje.
MODELLING THE CARBONATED CONCRETE REALKALIZATION
Authors: Jaśniok Mariusz , Zybura Adam
Published: June 2009

The presented model of carbonated concrete realkalization is compiled on the basis of the multi‐component medium theory equations. The process equations have been obtained from an analysis of the partial equations of mass, electric charge, momentum, energy, and entropy inequality. The experimental testing reported is related to a theoretical model which determines changes of ion concentrations in the pore solution of the cover, as a result of the realkalization. On the basis of the test results, the process equations have been simplified and formally transformed into the form of an equation for the OH– ions flow, coupled with the Na+ions transport. By solving the converse problem of this equation, the determinant OH– ions electro-diffusion coefficient is calculated and then, after taking the experimental test results into account, its numerical values, the range of stable solutions and the influence of the process non-stationariness are determined.

Santrauka

Karbonatizavusio betono šarminės terpės atkūrimo modelis sudarytas remiantis daugiakomponentės aplinkos teorijos lygtimis. Procesą aprašančios lygtys sudarytos atlikus masės balanso, elektros krūvio, judesio kiekio, energijos, taip pat entropijos nevienodumo parcialinių lygčių analizę. Eksperimentiniai tyrimai susieti su teoriniu modeliu apibrėžiant jonų koncentracijos pokytį tirpale apsauginio sluoksnio porose atkuriant šarminę terpę. Remiantis bandymų rezultatų analize, procesą aprašančios lygtys supaprastintos ir formaliai pertvarkytos į lygtis, aprašančias OH¯ jonų, susietų su Na+ jonais, pernešimu. Išsprendus šį uždavinį atvirkštiniu keliu, išreikštas OH¯ jonų elektrodifuzijos koeficientas ir, remiantis eksperimentinių tyrimų rezultatais, nustatyta jo skaitinė reikšmė, sunkiai skaidomų tirpalų sritis, taip pat proceso nepastovumo įtaka.
INFLUENCE OF VISCOSITY ENHANCING AGENT ON RHEOLOGY AND COMPRESSIVE STRENGTH OF SUPERPLASTICIZED MORTARS
Authors: Gołaszewski Jacek
Published: June 2009

The results of investigation into the influence of Viscosity Enhancing Agents (VEA) on the rheological properties of mortars, different in cement and superplasticizer properties, are presented and discussed. Rheology results have been evaluated according to the Bingham model, which describes the rheology with 2 parameters: yield value and plastic viscosity. Rheological parameters were measured using Two‐Point Workability Test (TPWT). Additionally, the influence of VEA on compressive strength of mortars is presented. It was found that effects of VEA addition on rheological properties of mortars, as well as on compressive strength of mortars, significantly depend on cement and superplasticizer properties. Basic relation of influence of VEA on rheological properties and compressive strength of mortars in respect to cement and superplasticizer properties were presented and discussed. It is concluded that addition of VEA influences compatibility between cement and superplasticizer. Because addition of VEA may cause decrease in compressive strength, the assessment of compatibility of VEA ‐ cement ‐ superplasticizer system should be performed in relation not only to rheological properties, but also to compressive strength. Santrauka Straipsnyje pateikta ir išanalizuota klampą didinančių priedų įtaka skiedinių reologinėms savybėms. Skiediniai buvo ruošiami su įvairių savybių cementais ir superplastikliais. Reologijos tyrimų rezultatai įvertinti remiantis Binghamo modeliu. Reologinės savybės buvo tiriamos dviejų parametrų reometru (TPWT). Taip sudarytas naturalus šviežio skiedinio ir betono mišinio reologinės elgsenos būvis. Straipsnyje taip pat pateikti klampą didinančių priedų įtakos betono stipriui giuždant rezultatai. Nustatyta, kad klampą didinančių priedų poveikio efektas skiedinių reologinėms savybėms ir stipriui gniuždant iš esmės priklauso nuo cemento ir superplastiklių savybių.
ON THE PHYSICALLY NON‐LINEAR ANALYSIS OF CYCLIC LOADED REINFORCED CONCRETE CROSS‐SECTIONS WITH MATHEMATICAL OPTIMISATION
Authors: Raue Erich , Timmler Hans-Georg , Garke Robert
Published: June 2009

In the paper, experimental results of tension member tests are used as a basis from which to develop an extended tension stiffening model for reinforced concrete, with emphasis on the specific concrete damage and the developments of residual deformations depending on the structural loading. Two characteristics are contained in the proposed model: one describes the residual deformation behaviour along the reinforcement accounting for the cracks that cannot be closed completely, while the other describes the degradation of the concrete stiffness. Within context of non‐linear analysis, the model is incorporated into an analytical approach, based on the LAG RANGE principle of minimum of total potential energy. The mechanical problem is solved with the application of the mathematical optimisation, using energy principles formulated as a kinematic formulation and transforming them into non‐linear optimisation problems. It was demonstrated, that this approach is eminently suitable for analysing pre‐damaged or pre‐loaded reinforced concrete cross‐sections under cyclic loading.

Santrauka

Pateikti tempiamųjų gelžbetoninių elementų eksperimentinių tyrimų rezultatai. Remiantis šiais rezultatais pasiūlytas supleišėjusio tempiamojo betono modelis, kuriame įvertinama betono pažaidų ir liekamųjų deformacijų didėjimo įtaka tempiamųjų gelžbetoninių elementų elgsenai. Modelis susideda iš dviejų komponentų: pirmasis aprašo išilginių liekamųjų deformacijų armatūroje kitimą, o antrasis betono įtakos elemento skerspjūvio deformacijoms mažėjimą. Netiesinė analizė atliekama taikant analizinį algoritmą, kuris pagrįstas Lagranžo potencinės energijos minimalumo principu. Mechaninė problema išspręsta taikant matematinį optimizavimą ir energinius principus. Pastarieji aprašyti kinematinėmis formuluotėmis jas perkeliant į netiesinio optimizavimo uždavinio algoritmus. Parodyta, kad pasiūlytas algoritmas gerai tinka cikline apkrova veikiamiems gelžbetoniniams elementams analizuoti.