bluuebunny/crossref_metadata_2025 huggingface dataset:
CCN6 (WISP3) decreases ZEB1-mediated EMT and invasion by attenuation of IGF-1 receptor signaling in breast cancer
Authors: Lorenzatti Guadalupe , Huang Wei , Pal Anupama , Cabanillas Ana M. , Kleer Celina G.
Published: April 2011

During progression of breast cancer, CCN6 protein exerts tumor inhibitory functions. CCN6 is a secreted protein that modulates the insulin-like growth factor-1 (IGF-1) signaling pathway. Knockdown of CCN6 in benign mammary epithelial cells triggers an epithelial to mesenchymal transition (EMT), with upregulation of the transcription factor ZEB1/δEF1. How CCN6 regulates ZEB1 expression is unknown. We hypothesized that CCN6 might regulate ZEB1, EMT and breast cancer invasion by modulating IGF-1 signaling. Exogenously added human recombinant CCN6 protein was sufficient to downregulate ZEB1 mRNA and protein levels in CCN6-deficient (CCN6 KD) HME cells and MDA-MB-231 breast cancer cells. Recombinant CCN6 protein decreased invasion of CCN6 KD cells compared with controls. We discovered that knockdown of CCN6 induced IGF-1 secretion in HME cells cultivated in serum-free medium to higher concentrations than found in MDA-MB-231 cells. Treatment with recombinant CCN6 protein was sufficient to decrease IGF-1 protein and mRNA to control levels, rescuing the effect of CCN6 knockdown. Specific inhibition of IGF-1 receptors using the pharmacological inhibitor NVP-AE541 or short hairpin shRNAs revealed that ZEB1 upregulation due to knockdown of CCN6 requires activation of IGF-1 receptor signaling. Recombinant CCN6 blunted IGF-1-induced ZEB1 upregulation in MDA-MB-231 cells. Our data define a pathway in which CCN6 attenuates IGF-1 signaling to decrease ZEB1 expression and invasion in breast cancer. These results suggest that CCN6 could be a target to prevent or halt breast cancer invasion.
Novel Method for Generating Large Mesopores in an Amorphous Silica–Alumina by Controlling the Pore Size with the Gel Skeletal Reinforcement and Its Catalytic Cracking Properties as a Catalyst Matrix
Authors: Ishihara Atsushi , Nakajima Kohei , Hirado Motoki , Hashimoto Tadanori , Nasu Hiroyuki
Published: April 2011

The pore size of amorphous silica and silica–alumina with large mesopores was controlled for the first time in the range of 5 to 30 nm by gel skeletal reinforcement. The conversion and the ratio of multi-branched to single-branched products increased with increasing the pore diameter of silica–alumina in catalytic cracking of n-dodecane with its use as a matrix.
Oxygen Permeability Change of Polyphenylacetylene Derivatives by Postfunctional TCNE Addition
Authors: Li Yongrong , Hyakutake Tsuyoshi , Michinobu Tsuyoshi
Published: April 2011

Polyphenylacetylene derivatives substituted by dialkylanilino-appended alkyne side chains were synthesized by Rh-catalyzed polymerization. Improved oxygen barrier ability was achieved by the postfunctional, controlled introduction of four nitrile groups into the repeat unit of the polyphenylacetylene derivatives.
Transient pseudohypoaldosteronism masquerading as congenital adrenal hyperplasia
Authors: Manikam L , Cornes M P , Kalra D , Ford C , Gama R
Published: April 2011

We report a six-week-old boy with genitourinary structural abnormalities who presented with profound hyponatraemia and hyperkalaemia due to transient type 1 pseudohypoaldosteronism (PHA) precipitated by a urinary tract infection (UTI), which responded rapidly to intravenous saline and antibiotics. In infants with structural abnormalities of the urinary tract, we wish to highlight the importance of recognizing type 1 PHA and its association with a UTI since prompt and appropriate treatment rapidly corrects the associated metabolic abnormalities. Conversely, the identification of type 1 PHA in an infant should precipitate a search for a UTI and structural abnormalities of the urinary tract.
Prostate-specific antigen: does the current evidence support its use in prostate cancer screening?
Authors: Duffy Michael J
Published: April 2011

Although widely used, the value of prostate-specific antigen (PSA) in screening asymptomatic men for prostate cancer is controversial. Reasons for the controversy relate to PSA being less than an ideal marker in detecting early prostate cancer, the possibility that screening for prostate cancer may result in the overdetection and thus overtreatment of indolent disease and the lack of clarity as to the definitive or best treatment for men diagnosed with localized prostate cancer. Although the results from some randomized prospective trials suggest that screening with PSA reduces mortality from prostate cancer, the overall benefit was modest. It is thus currently unclear as to whether the modest benefit of reduced mortality outweighs the harms of overdetection and overtreatment. Thus, prior to undergoing screening for prostate cancer, men should be informed of the risks and benefits of early detection. Newly emerging markers that may complement PSA in the early detection of prostate cancer include specific isoforms of PSA and PCA3.
Zinc poisoning from excessive denture fixative use masquerading as myelopolyneuropathy and hypocupraemia
Authors: Barton A L , Fisher R A , Smith G D P
Published: April 2011

A 50-year-old man presented with a four-year history of unsteadiness, with recent falls and tingling in his fingers. Neurological examination found an ataxic gait, with a positive Romberg's sign. There was distal wasting and weakness in all four limbs and impaired co-ordination, with pseudoathetosis in the arms. Initial investigations showed a normochromic, normocytic anaemia, leucopenia, neutropenia and a low vitamin B12 (172 ng/L). Treatment with intramuscular cobalamin injections showed no clinical improvement. Further investigations showed an undetectable caeruloplasmin (<0.085 g/L), a very low serum copper (1.1 μmol/L) and a markedly raised serum zinc concentration (36.2 μmol/L). On detailed questioning it became apparent that he had ill-fitting dentures requiring excessive use of denture fixative with high zinc content. The patient was switched to a non-zinc containing denture fixative and commenced copper supplementation. Although within three months the bone marrow suppression had resolved, there was no clinical improvement in neurological presentation. Questioning a patient about their denture fixative usage and checking if zinc is an ingredient may be considered during an investigation for myelopolyneuropathy when vitamin B12 deficiency is not a cause.
Estimation of organ-absorbed radiation doses during 64-detector CT coronary angiography using different acquisition techniques and heart rates: a phantom study
Authors: Matsubara Kosuke , Koshida Kichiro , Noto Kimiya , Takata Tadanori , Shimono Tetsunori , Kawashima Hiroko , Yamamoto Tomoyuki , Matsui Osamu
Published: April 2011

Background

Though appropriate image acquisition parameters allow an effective dose below 1 mSv for CT coronary angiography (CTCA) performed with the latest dual-source CT scanners, a single-source 64-detector CT procedure results in a significant radiation dose due to its technical limitations. Therefore, estimating the radiation doses absorbed by an organ during 64-detector CTCA is important.

Purpose

To estimate the radiation doses absorbed by organs located in the chest region during 64-detector CTCA using different acquisition techniques and heart rates.

Material and Methods

Absorbed doses for breast, heart, lung, red bone marrow, thymus, and skin were evaluated using an anthropomorphic phantom and radiophotoluminescence glass dosimeters (RPLDs). Electrocardiogram (ECG)-gated helical and ECG-triggered non-helical acquisitions were performed by applying a simulated heart rate of 60 beats per minute (bpm) and ECG-gated helical acquisitions using ECG modulation (ECGM) of the tube current were performed by applying simulated heart rates of 40, 60, and 90 bpm after placing RPLDs on the anatomic location of each organ. The absorbed dose for each organ was calculated by multiplying the calibrated mean dose values of RPLDs with the mass energy coefficient ratio.

Results

For all acquisitions, the highest absorbed dose was observed for the heart. When the helical and non-helical acquisitions were performed by applying a simulated heart rate of 60 bpm, the absorbed doses for heart were 215.5, 202.2, and 66.8 mGy for helical, helical with ECGM, and non-helical acquisitions, respectively. When the helical acquisitions using ECGM were performed by applying simulated heart rates of 40, 60, and 90 bpm, the absorbed doses for heart were 178.6, 139.1, and 159.3 mGy, respectively.

Conclusion

ECG-triggered non-helical acquisition is recommended to reduce the radiation dose. Also, controlling the patients’ heart rate appropriately during ECG-gated helical acquisition with ECGM is crucial.
Percutaneous radiofrequency ablation of renal cell carcinomas in patients with von Hippel Lindau disease previously undergoing a radical nephrectomy or repeated nephron-sparing surgery
Authors: Park Sung Yoon , Park Byung Kwan , Kim Chan Kyo , Lee Hyun Moo , Jeon Seong Soo , Seo Seong Il , Jeong Byong Chang , Choi Han Yong
Published: April 2011

Background

Radiofrequency ablation (RFA) is accepted as a minimally invasive treatment of renal cell carcinoma (RCC). However, RFA is not fully evaluated for treating RCC in patients with von Hippel Lindau (VHL) disease who cannot undergo surgery due to serious postoperative morbidity or mortality.

Purpose

To evaluate the role of RFA of RCC in patients with VHL disease previously undergoing renal surgery.

Material and Methods

Percutaneous RFA was performed for treating 14 RCCs in six patients who had undergone radical nephrectomy ( n = 3) or repeated nephron-sparing surgery ( n = 3). Treatment feasibility, complications, outcome, and the change of renal function were evaluated.

Results

To completely ablate 14 RCCs, 23 ablations during 12 sessions were necessary. Of 14 RCCs, nine were in proximity (<5 mm) to one or more following organs: bowel ( n = 4), ureteropelvic junction or pelvis ( n = 2), psoas muscle ( n = 2), vascular pedicle ( n = 1), and pancreas ( n = 1). Of 12 sessions, one major complication (pneumothorax) developed in one session (8%). No residual or recurrent tumors were identified at the ablation areas. However, new three solid tumors less than 1 cm in diameter developed during the follow-up period but ablation was withheld until these tumors had grown to more than 1 cm in size. The mean level of serum creatinine increased with 6.4% and the mean estimated glomerular filtration rate decreased by 12.8% after the last ablation compared to those before the initial ablation ( P < 0.05).

Conclusion

Despite technical difficulties, percutaneous RFA is a promising treatment for VHL patients who cannot undergo surgery because of excellent treatment outcome and minimal change of renal function.
Influence of adenosine on ventricular function measurements as part of a comprehensive stress perfusion magnetic resonance imaging study
Authors: Sievers Burkhard , Jacobi Liane , Sommer Philipp , Speiser Uwe , Schoen Steffen , Strasser Ruth H
Published: April 2011

Background

Stress-rest perfusion magnetic resonance imaging (MRI) has become one of the major indications for cardiovascular MRI. Standard multibreath hold short-axis image acquisition is the gold standard for LV function assessment and part of a comprehensive stress-rest perfusion MRI study, but takes up to 10 min. The total scan time could significantly be shortened when cine imaging would be performed between stress and rest perfusion.

Purpose

To systematically study whether adenosine, albeit its short half-life time, influences LV function measurements in this setting.

Material and Methods

Thirty-nine patients with suspected and/or known coronary artery disease underwent 3-Tesla adenosine (140 µg/min/kg) stress-rest perfusion MRI. A stack of short-axis slices covering the entire ventricles was acquired before and ≥3 min after adenosine infusion using standard multibreath-hold 2D steady-state free precession imaging. LV volumes (EDV, ESV), EF, and mass were calculated by the slice summation method, and wall motion was assessed using a 4-point scoring scale. Reproducibility was assessed by Bland-Altman statistics.

Results

EDV, ESV, EF, and mass were not significantly different between the two imaging time points (before versus after adenosine administration) in all patients ( P ≥ 0.346) and patients with impaired LV function ( P ≥ 0.718). Wall motion scores did not differ either ( P ≥ 0.124). Inter-observer variability before ( P ≥ 0.468) and after ( P ≥ 0.451) adenosine infusion was low.

Conclusion

Short-axis cine imaging for LV function assessment can accurately be performed between stress and rest imaging. These data demonstrate that potential effects of adenosine on LV function are of short duration, and propose a new time-saving imaging protocol without compromising accuracy.
Thrombosis and cancer: spectrum of multidetector CT findings in oncologic patients with thromboembolic disease. A pictorial review
Authors: Catalano Orlando , Nunziata Antonio , di Castelguidone Elisabetta de Lutio , d'Errico Adolfo Gallipoli
Published: April 2011

This article is a reasoned pictorial review illustrating the many faces of thrombotic and embolic disease developing in the cancer patient. From a clinical point of view, we particularly point out the importance of properly identifying this occurrence in its various presentations. From a radiological point of view, special emphasis is given to the wide spectrum of multidetector CT findings, to the clues of benign and malignant thrombus diagnosis, and to the potential interpretative pitfalls.
Radiologic characteristics of sinonasal fungus ball: an analysis of 119 cases
Authors: Seo Young-Joon , Kim Jinna , Kim Kyubo , Lee Jeung-Gweon , Kim Chang-Hoon , Yoon Joo-Heon
Published: April 2011

Background

It is important to differentiate sinonasal fungus ball from non-fungal sinusitis and other forms of fungal sinusitis in order to determine the optimal treatment. In particular, a sinonasal fungus ball, a non-invasive fungal sinusitis, can be characterized by radiologic findings before surgery.

Purpose

To differentiate a sinonasal fungus ball from other types of sinusitis and determine optimal treatment on the basis of radiologic findings before surgery.

Material and Methods

We studied 119 patients with clinically and pathologically proven sinonasal fungus balls. Their condition was evaluated radiologically with contrast-enhanced CT (99 patients), non-contrast CT (18 patients) and/or MRI (17 patients) prior to sinonasal surgery.

Results

Calcifications were found in 78 of 116 (67.2%) patients who underwent CT scans for fungus ball. As opposed to non-contrast CT scans, contrast CT scans revealed hyperattenuating fungal ball in 82.8% and enhanced inflamed mucosa in 65.5% of the patients, respectively. On MRI, most sinonasal fungal balls showed iso- or hypointensity on T1-weighted images and marked hypointensity on T2-weighted images. Inflamed mucosal membranes were noted and appeared as hypointense on T1-weighted images (64.7%) and hyperintense on T2-weighted images (88.2%).

Conclusion

When there are no calcifications visible on the CT scan, a hyperattenuating fungal ball located in the central area of the sinus with mucosal thickening on enhanced CT scans is an important feature of a non-invasive sinonasal fungus ball. On MRI, a sinonasal fungus ball has typical features of a marked hypointense fungus ball with a hyperintense mucosal membrane in T2-weighted images. A contrast-enhanced CT scan or MRI provides sufficient information for the preoperative differentiation of a sinonasal fungus ball from other forms of sinusitis.
Risk factors and clinical presentation of hepatitis C virus infection in Nigerians with chronic liver disease
Authors: Olokoba Abdulfatai B , Accama Laraba A , Gashau Wadzani , Salawu Fatai K
Published: April 2011

Chronic liver disease is becoming a major public health problem in Nigeria and hepatitis C virus is becoming a significant causative factor in its aetiology worldwide and in Nigeria. We determined the risk factors and clinical presentation of hepatitis C virus infection in Nigerians with chronic liver disease. A structured interviewer-administered questionnaire was administered in order to determine the risk factors for hepatitis C virus infection and a physical examination was carried out in order to determine the clinical presentation. Ninety patients with clinical, biochemical and sonographic evidence of chronic liver disease and 85 controls without liver disease were studied. Anti-HCV antibodies were detected in 14.4% and 2.4% of patients and controls, respectively ( P < 0.05). The main risk factors were scarification, traditional surgery and blood transfusion. Ascites, jaundice, pedal swelling, abdominal distension, hepatomegaly, abdominal pain and splenomegaly were the main presentations.
Effect of the Adsorptive Character of Filter Papers on the Concentrations Determined in Studies Involving Heavy Metal Ions
Authors: Engin Mehmet Soner , Uyanik Ahmet , Cay Seydahmet , Icbudak Hasan
Published: April 2011

Analytical filter papers are generally made of fibrous cellulose which has the potential to adsorb metal ions. In this study, blue band ashless filter paper was used to demonstrate one of the sources of error in the determination of the concentration of Fe2+, Co2+, Mn2+, Cd2+, Cu2+, Pb2+ and Zn2+ ions. For this purpose, the metal ion content of standard solutions in the 1–100 mg/ℓ concentration range was analysed via FAAS before and after the filtration process. The corresponding results and the calculated percentage errors due to adsorption are presented. The effect of pH on the adsorption process was also investigated. Activated carbon and soil samples were spiked with each metal ion and the solid phases from the resulting solutions were separated by both filter paper methods and centrifugation. In the statistical estimation of the results, the paired t-test was applied for non-filtered and filtered solutions in the concentration range 1–100 mg/ℓ using the data analysis tools available in MS Excel®. The use of filter paper caused systematic errors, particularly at lower metal concentrations, and hence centrifugation or a filtering process using techniques other than filter paper is favoured as a better approach towards estimating the concentration of heavy metal ions from aqueous solution.
Adsorption of Cu(II) Ions onto a Cellulosic Biosorbent, Azadirachta Indica Leaf Powder: Application in Water Treatment
Authors: Bhattacharyya Krishna Gopal , Sarma Arunima , Sarma Jyotirekha
Published: April 2011

In the present work, Azadirachta indica (neem) leaves were converted to a powder for use in the separation of Cu(II) ions from water. The powdered biomass was investigated as a sorbent for Cu(II) ions employing pH, time, initial Cu(II) ion concentration and the amount of sorbent as the experimental variables. At very low pH, Cu(II) ions were incapable of competing effectively with H+ ions for the sorption sites, but at the natural pH (5.6) of the aqueous Cu(II) ion solution up to 90% of the Cu(II) ions could be separated by sorption onto 4 g of Azadirachta indica leaf powder (AILP) from an aqueous solution of 50 mg/ℓ concentration. The experimental data were well fitted by the Langmuir and Freundlich isotherm equations and followed pseudo-second-order kinetics. The Langmuir monolayer capacity of AILP for Cu(II) ions was 6.7–33.3 mg/g, which could be considered as reasonable. Azadirachta indica leaf powder could be a very effective sorbent for Cu(II) ions from an aqueous medium. The cellulosic units present in AILP provide a matrix of OH−, COO−, CN− and other anions that bind Cu(II) ions to the surface. The process was exothermic with ΔH0 values of −96.1 kJ/mol to −105.4 kJ/mol, reflecting the strong Cu(II)–AILP linkages formed. This was supported by an appropriate increase in the standard entropy change and a decrease in the Gibbs' free energy.
Effect of Small Organic Acid Anions on the Adsorption of Phosphate Anions onto Synthetic Goethite from Aqueous Solution
Authors: Shi Zhongliang , Li Fang , Yao Shuhua
Published: April 2011

Batch experiments were conducted to study the effect of small organic acids (citric, oxalic and acetic) on the removal of phosphate anions from aqueous systems using synthesized goethite as the adsorbent. The results showed that phosphate anion adsorption was most significantly inhibited by citric among the three organic acids studied. Phosphate anion adsorption was affected at pH values below 6.5. The relationship between citrate anionpromoted goethite dissolution and citrate anion-suppressed phosphate anion adsorption in equilibrated goethite–phosphate anion–citric acid systems with different contact orders was studied. The results indicated that there is an obvious correlation between the suppression of phosphate anion adsorption and the dissolution of goethite. It is proposed that competition for binding sites play a key role in the reduction of phosphate anion adsorption by citric acid.
Ethyl Acetate Adsorption onto Activated Carbon
Authors: Branton Peter , Urita Koki , Kaneko Katsumi
Published: April 2011

The adsorption and desorption of ethyl acetate on a coconut-based activated carbon has been studied using static and flow adsorption methods at different temperatures from 295 K to 325 K. The adsorbed state of ethyl acetate was studied using nitrogen adsorption at 77 K after the pre-adsorption of ethyl acetate. The adsorption isotherms of ethyl acetate were of Type I in the IUPAC classification, suggesting micropore filling by ethyl acetate molecules. The micropore volume of the activated carbon as evaluated from ethyl acetate adsorption using the liquid density of ethyl acetate agreed well with that from nitrogen adsorption. Nitrogen adsorption after pre-adsorption of ethyl acetate indicated considerably packed molecular states of ethyl acetate molecules within the micropores. Thus, ethyl acetate molecules can migrate to the deeper parts of micropores in the case of static adsorption measurements. However, the specific surface area evaluated from ethyl acetate adsorption was nearly 40% smaller than that from nitrogen adsorption under the assumption of an isotropic structure. The assumption of a highly orientated adsorption structure for ethyl acetate molecules on the pore wall led to a good correlation even as far as the surface area was concerned. In addition, 26 kJ/mol of the excess stabilization energy determined from the temperature dependence of the ethyl acetate adsorption isotherm supports the favourable molecular alignment of ethyl acetate molecules which increases the molecule–pore wall interactions.
Dependence of Water Vapour Adsorption on the Polarity of the Graphene Surfaces of Multi-Wall Carbon Nanotubes
Authors: Bradley Robert H. , Andreu Aurik , Cassity Kelby , Osbeck Susan , Andrews Rodney , Meier Mark , Johnston Colin
Published: April 2011

The adsorption of water by the graphene surfaces of multi-wall carbon nanotubes (MWCNTs) in either the untreated (4.3 atom% oxygen) or oxidised (22.3 atom% oxygen) surface states has been studied. Different concentrations of surface oxygen groups, which have been directly measured using XPS, give rise to distinctly different shapes of water adsorption isotherms. Those from the untreated materials follow the pressure axis which lends them a Type III character in the BDDT classification. However, since they display a clear point of inflection at the lowest pressure, they are strictly speaking Type II isotherms but indicative of relatively few polar interactions and weak water adsorptivity. In sharp contrast, the isotherms from the oxidised MWCNTs are typically Type II and are characterised by a marked positive curvature in their low pressure region due to the increased numbers of specific interactions occurring between water molecules and the polar surface oxygen groups.

The water adsorption data were modelled by the equation of D'Arcy and Watt with a direct correlation being observed between the surface polarity parameters (amL and a0) and also as (the limiting water uptake) and the surface oxygen levels of the MWCNTs. The difference in polar surface energy was confirmed by measurements of the calorimetric enthalpies of immersion in water (Δhi), which were −54 mJ/m2 for the untreated and −192 mJ/m2 for the oxidised materials. These values also reflect the difference in the integral net enthalpies of adsorption for the two hydrophilic surfaces: a value of ca. −35 mJ/m2 being obtained for an oxygen-free (hydrophobic) surface. Water adsorption on these hydrophilic graphene surfaces was shown to occur by specific hydrogen bonding and was therefore strongly dependent on the numbers of oxygen-containing polar surface sites. This behaviour is well known for other types of porous and non-porous carbon materials and is also predicted for carbon nanotubes by molecular simulation studies. The work described herein therefore provides early experimental confirmation of the quantitative role of surface oxygen chemistry in determining the water adsorption character of MWCNT graphene surfaces; it also validates previous simulation studies.
Modelling the Adsorption of p-Nitrophenol by the Boyd Method in Conjunction with the Finite Element Method
Authors: Zamora Francisco , Sabio Eduardo , Román Silvia , González-García Carmen María , Ledesma Beatriz
Published: April 2011

Adsorption kinetics are often studied by non-dimensional models that allow a good fitting of the experimental data. Nevertheless, their physical interpretation is very limited because the particle geometry is not considered. In this work, the adsorption kinetics of p-nitrophenol onto two commercial activated carbons with different textural and geometrical characteristics was studied. For this purpose, two types of models were used: zero-dimensional models which do not take the system geometry into account; and the Boyd model, which takes the shape of the adsorbent molecule into account. In contrast to previous published works, the Boyd model was solved by means of the finite element method using the commercial software COMSOL. This paper provides a new insight into the modelling of adsorption kinetics when non-spherical adsorbents are employed.
Modelling the Desorption of Ethanol from an Externally Heated Saturated Activated Carbon Column by Purging with Air
Authors: Delgado José A. , Uguina María A. , Sotelo José L. , Águeda Vicente I. , Gómez Pilar , Hernández Verónica
Published: April 2011

The desorption of ethanol from an externally heated column loaded with activated carbon and purged with air has been studied. The column was initially saturated with liquid ethanol. This process simulates the regeneration step in a concentration-swing/thermal-swing adsorption process for the production of fuel-grade ethanol. A theoretical model was developed for describing the mass- and heat-transfer kinetics of the process. Validation of the model was achieved by comparing its predictions with experimental data, employing initial column temperatures between 298 K and 395 K and air flow rates between 1.6 × 10−6 m3/s and 11.3 × 10−6 m3/s. Experimentally measured adsorption isotherms of ethanol from ethanol/air gas mixtures onto activated carbon, as well as the regeneration column dynamics, are reported.
Adsorption of Thiocyanate Anions from Aqueous Solution onto Adsorbents of Various Origin
Authors: Aguirre Noelia V. , Vivas Beatriz Padilla , Montes-Morán Miguel A. , Ania Conchi O.
Published: April 2011

The removal of thiocyanate, a toxic anion originating in a large number of industrial processes, from aqueous solutions was investigated using adsorbents of different natures (activated carbon, zeolite, diatomite, sepiolite, hydrotalcite, steel-making residues). The uptake of thiocyanate anions did not seem to be directly related to the porous features of the adsorbents, but rather connected to the ion–adsorbent affinity. The highest retention in synthetic solutions was obtained with hydrotalcite, followed by activated carbon, zeolite and the steel-making slags. In real wastewater, the removal efficiency of hydrotalcite relative to industrial wastewater was largely suppressed due to the organic matter present. In contrast, the retention ability of the activated carbon and the slags was less modified in real wastewater due to their open porous networks. These results indicate that steel-making slag could be used as a potential adsorbent for the removal of thiocyanate anions from real wastewater produced in coke-making processes without any additional processing.
Porous Silicas and Respective Carbon Replicates for Adsorption and Catalysis
Authors: Pires João , Borges Susana , Carvalho Ana P. , Silva Ana R.
Published: April 2011

A recent pathway for obtaining regular mesoporous materials (silicas and carbons) in one step was explored in this work using TEOS, P123 and sucrose as a starting base template. The synthesis was catalyzed by H2SO4. The mesoporous carbon was obtained by carbonization of the previous mixture and the removal of the silica template. In contrast, when the composite mixture was heated in air, a mesoporous silica was obtained. The results showed that the “one-pot” method presented some difficulties in controlling the synthesis variables. All the silica samples presented a more regular pore-size distribution than the respective carbon replicate. The specific surface areas (ABET) of the prepared materials were in the range 500–600 m2/g for the silica samples and within the range 1000–1200 m2/g for the carbon samples.
Study of the Mechanisms Involved in the Adsorption of Amitriptyline from Aqueous Solution onto Activated Carbons
Authors: Ledesma B. , Román S. , González J.F. , Zamora F. , Rayo M.C.
Published: April 2011

Two commercial activated carbons (DA and CB) differing in their porosity (one being microporous and the other mesoporous) and in their surface chemistries (one being acidic and the other basic in character) were modified by thermal and oxidizing treatment in order to change their surface properties. The changes induced by these processes were studied by means of ultimate analyses, nitrogen adsorption isotherms measured at −196 °C, mercury porosimetry, FT-IR spectroscopy and determination of their point of zero charge (PZC) values. Subsequently, the adsorption of amitriptyline onto both the pristine and treated carbons was studied at pH values of 3 and 7 and a temperature of 25 °C. The results obtained allowed the possible mechanisms governing the adsorption process to be analyzed in order to optimize the type of adsorbent needed to remove this particular drug from aqueous solution.
Adsorption Isotherms of Methylene Blue in Aqueous Solution onto Activated Carbons Developed from Vine Shoots (Vitis Vinifera) by Physical and Chemical Methods
Authors: Ruiz-Fernández María , Alexandre-Franco María , Fernández-González Carmen , Gómez-Serrano Vicente
Published: April 2011

Carbonaceous adsorbents (CAs) developed from vine shoots ( Vitis Vinifera, VS) and characterized texturally were used for the adsorption of Methylene Blue (MB) from aqueous solution. The CAs were prepared by physical activation in air, carbon dioxide and steam, and by chemical activation with H3PO4, ZnCl2 and KOH. One commercial activated carbon (CAC) was also used. The CAs were analyzed texturally by gas adsorption, mercury porosimetry and density measurements. Physical activation yielded mainly macroporous CAs, whereas chemical activation gave rise to mainly mesoporous CAs with high micro- and macro-pore contents. CAC was an essentially microporous carbon. The affinity of MB towards the CAs was usually low, except for the carbon prepared by activation of VS with KOH at 800 °C for 2 h. This AC exhibited a better behaviour in the adsorption of MB than CAC. The development of macroporosity in the KOH activation product was considerable.
Modelling the Breakthrough Curves Obtained from the Adsorption of Propene onto Microporous Inorganic Solids
Authors: Puértolas Begoña , López María R. , Navarro María V. , López José M. , Murillo Ramón , García Tomás , Mastral Ana M.
Published: April 2011

The modelling of breakthrough curves obtained in the adsorption of propene as a model compound onto different inorganic solids is described. All the runs were performed in a fixed bed at atmospheric pressure, employing a process temperature of 30 °C and propene concentrations in the range 0.0022–0.0222 mol/Nm3. The experimental conditions were therefore similar to those observed in the initial flue gases of cold start engines. The work described was mainly focused on the study of the influence of the adsorbent characteristics (composition, porous structure and surface area) on the kinetics of the adsorption process. The equilibrium adsorption values were initially determined from the breakthrough curves and satisfactorily fitted by the Langmuir isotherm model. These values were then used together with experimental breakthrough curves to analyse the kinetic expressions obtained applying the Linear Driving Force (LDF) model to the dynamic adsorption process. Values of the mass-transfer coefficient, surface and effective diffusion coefficients of propene have been calculated and are reported.
Adsorption of Bovine Serum Albumin onto Mesocellular Silica Foams with Differently Sized Cells and Windows
Authors: Sezões F. , Carrott M.M.L. Ribeiro , Mourão P.A.M. , Carrott P.J.M.
Published: April 2011

As a model protein with quite large dimensions, Bovine Serum Albumin (BSA) has been used to evaluate the influence of the distinct pore structural characteristics of three mesocellular foam (MCF) materials prepared with or without the addition of ammonium fluoride and with varying 1,3,5-trimethylbenzene/Pluronic P123 (TMB/P123) ratios. SBA-15 was also studied for comparative purposes. Characterisation by X-ray diffraction and electron microscopy confirmed the characteristic spheroid cell structure of the MCF pores. Nitrogen adsorption/desorption isotherms at 77 K revealed the different pore structural parameters of the MCF, viz. pore volume (1.8–2.4 cm3/g), cell size (24.6–28.5 nm) and window size (11.3–17.3 nm), as obtained by the NLDFT method. The equilibrium adsorption isotherms and the kinetic adsorption data for BSA at 298 K and pH 5 were well fitted by the Langmuir model and pseudo-second-order kinetic model, respectively.

The results showed that adsorption onto the material possessing a window size of 11.3 nm was mostly restricted to the external surface, while a considerable increase in the maximum adsorption capacity from 120 mg/g to 500–600 mg/g was observed when the window size was above the critical dimension of 13.9 nm. In the latter cases, the maximum adsorption capacities could be related to the pore volume rather than to the total surface area. The confined BSA molecules were strongly immobilised in the cells, since only a small proportion was desorbed from the material with windows of 17.3 nm dimensions on contact with a buffer solution of pH 7.
Simulations of Phenol Adsorption onto Activated Carbon and Carbon Black
Authors: Prosenjak Claudia , Nabais João M. Valente , Laginhas Carlos E. , Carrott Peter J.M. , Carrott Manuela M.L. Ribeiro
Published: April 2011

Grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations have been used to study the adsorption of phenol onto carbon materials. Activated carbon was modelled in terms of its pore-size distribution based on DFT methods, while carbon black was represented by a single carbon slab with varying percentages of surface atoms removed. GCMC results for adsorption from the corresponding gas phase were in reasonable agreement with experimental adsorption results. MD simulations, that studied the influence of the presence of water and surface roughness on the arrangement of the adsorbed phenol molecules, showed that the interaction between the adsorbed molecules was strongly influenced by the presence of water.
Adsorption Properties of Activated Carbons Prepared from Recycled PET in the Removal of Organic Pollutants from Aqueous Solutions
Authors: Cansado Isabel P.P. , Galacho Cristina , Nunes Ângela S. , Carrott Manuela L.R. , Carrott Peter J.M.
Published: April 2011

Activated carbons (ACs) were prepared from recycled polyethylene terephthalate (PET) by chemical activation with KOH and used successfully for the removal of 4-chloro-2-methylphenoxyacetic acid (MCPA) and Methylene Blue (MB) from aqueous media. In order to improve the adsorption capacity towards pollutant removal, the AC was submitted to different post-treatments. After oxidation, the sample exhibited an increase in MB adsorption capacity but showed a decreased MCPA adsorption removal extent. High-temperature treatment was not favourable for increasing the MB or MCPA adsorption capacity. However, after treatment with sodium hydroxide or urea, the samples showed a significant increase in their MCPA adsorption capacities. Normalisation of the MB and MCPA adsorption data with respect to the micropore volume led to a clearer understanding of the influence of the textural and chemical characteristics of the AC on the removal of MB and MCPA. The MB and MCPA adsorption isotherms were analysed via the Langmuir and Freundlich models, with the calculated parameters accurately fitting the experimental data and exhibiting good agreement between them.
A Simulation Study of Hydrogen in Metal–Organic Frameworks
Authors: Bueno-Pérez Rocío , García-Pérez Elena , Gutiérrez-Sevillano Juan José , Merkling Patrick J. , Calero Sofía
Published: April 2011

Molecular simulations have been used to evaluate the effect exerted by metal centres on the adsorption and diffusion of hydrogen in metal–organic frameworks. Simulations were carried out for the MIL-53 (Cr and Al) structures and the isostructural vanadium analogue MIL-47 at room temperature. To validate the models and force fields used in this work, the adsorption isotherms, energies and entropies, and self-diffusivities in Cu–BTC and IRMOF-1 metal–organic frameworks were computed. Using the validated force fields and models, a detailed analysis of the preferential adsorption sites is reported, allowing the energetic contribution in the low-coverage regime (Henry constants and adsorption energies and entropies) to be determined as a function of loading (adsorption isotherms). The influence of each energetic contribution to the charged and uncharged models of hydrogen has also been analyzed.
Vibration Insulation Properties of Resilient Bars in Timber Floors
Authors: Su Shenzhi , Fairfield Charles A. , Smith R. Sean
Published: April 2011

As effective, low-cost isolators, resilient bars have become the dominant ceiling treatment for improving the sound insulation of apartment timber floors in the UK to meet increasingly stringent building regulations. There are many variations on the resilient bar theme available on the market, many differing only in their detailed features. Their acoustic performances are not however, consistent. This research investigated the isolating effects of resilient bars from four perspectives: that of their rotational resilience when acting as a spring hinge, considering their base flange as a spring, their ceiling flange as a spring and examining the spring effect provided by the bar in its longitudinal direction. Two types of experiment were designed: vibration transmission tests at 31.5 Hz ⪕ f ⪕ 5000 Hz on a small-scale timber floor model, and static stiffness tests on small resilient bar specimens. Data revealed the relative importance of key features while providing improved design guidance.
Adapting Simple Prediction Methods to Sound Transmission of Lightweight Foam Cored Panels
Authors: Ballagh K O
Published: April 2011

A common building product used in industrial buildings consists of thin steel or aluminium skins on each side of a foam plastic core such as polystyrene. Such panels have many attractive properties, they are light weight, have excellent capacity to span between structural supports, excellent thermal insulation and are pre-finished. They are used extensively in many countries, and in New Zealand these types of panels are commonly used in food processing plants which are often noisy and located close to residences. The sound transmission loss of these panels in their basic form is poor, usually less than a simple mass law prediction based on the mass of the components. The performance is characterised by a sharp dip in the sound transmission loss at mid frequencies which causes a big drop in Rw or STC rating. The work described in this paper has developed simple methods of predicting the sound transmission loss of panels both as single panels and more importantly when used as part of a system to achieve higher performance.
Sound Insulation Descriptors in Europe—Special Rules Complicate Harmonization within Lightweight Industry
Authors: Hagberg Klas , Bard Delphine
Published: April 2011

Many European countries have a sound classification standard connected to the building regulations in order to specify minimum requirements. The various national standards have a lot of similarities, however the acoustic descriptors differ more than what is obvious by a quick comparison of current classification standards. The different descriptors in each country are to some extent a heritage from the past, successively adapted to the building industry in each country and their certain traditions in building technique. The descriptors and the requirements are necessarily not based on subjective experience. Furthermore, to fulfil national interests and to fit to new design trends of housing units etc, the descriptors involve small local adaptations to each country. These local adaptations are not easy to find unless the standards are read carefully. This causes problem since the building industry is not restricted to national boundaries anymore. Many companies have activity in countries adjacent to each other and in future the probability for increased activity all across Europe and also outside Europe is to be expected, unless regulations restrict this development. Combining national special rules and some severe uncertainties in the measurement and evaluation procedures of sound insulation, the situation is more critical for lightweight structures. This is partly due to the fact that the development of building systems are made in one country, the production takes place in production plants, i.e. the production and the process are fitted to local regulations and are “standardized”. The standardized process is fast and dry but also needed due to lack of prediction models. And once the light weight system and the system process are established in one country it is complicated and expensive to adapt them to other countries. In this paper an overview of special national rules in some European countries and major problems connected to lightweight construction are presented.
Acoustic Conditions in Sustainable Buildings—Results of a Worldwide Survey of Users' Perceptions
Authors: Baird George , Dykes Clare
Published: April 2011

With the trend to sustainability and energy efficiency, buildings are being constructed that are attempting to be as ‘green’ as possible. One objective in this form of design is to provide a higher level of interior environmental quality than buildings that use conventional practices. Post Occupancy Evaluations have been carried out on 36 sustainable buildings in 11 different countries. This paper describes and analyses the users' overall perceptions of the acoustical conditions and the noise sources (in particular noise from colleagues, from other people, and from both inside and outside sources) in these buildings. The results from these analyses showed that people rate the overall interior environment of these sustainable buildings highly. However, the acoustic aspect tended to score rather less well than some other aspects of the interior environment. A strong correlation was found between the occupants' overall perception of noise and their perception of productivity in the workplace.
Impact Sound Pressure Level Performances of Basic Beam Floor Structures
Authors: Bettarello Federica , Fausti Patrizio , Baccan Vincenzo , Caniato Marco
Published: April 2011

In order to obtain reliable estimations of the impact sound insulation between rooms, it is necessary to know the acoustic performance of each element composing the floors. The contribution of the flanking transmissions, the attenuation of floating floors and the weighted normalized impact sound pressure level of the basic structure need to be determined in order to apply the simplified calculation method according to the EN ISO 12354-2 standard. With the aim of verifying the range of validity of the calculation method proposed by the EN ISO 12354-2 standard for typical basic beam floor structures, a research based on on-site measurements was conducted. This paper provides an analysis in terms of spectrum trend, predicted average weighted normalized impact sound pressure level and reduction of impact sound pressure level obtainable with a generic floating floor typology. The study can represent a starting point for a correct estimation of the impact sound insulation in new buildings and renovation plans.
Effect of Façade Shape for the Acoustic Protection of Buildings
Authors: Busa Lucia , Secchi Simone , Baldini Stefano
Published: April 2011

Façade sound insulation can be improved by using high performance components or by modifying the shape of the façade. In many cases, when high acoustic insulation levels are required, the use of high performance components cannot be sufficient, for technical or economic reasons.

The European standard EN 12354-3 [1] gives a simplified method to estimate the influence of the façade shape in the reduction of sound pressure level at the outside of the building envelope. In particular, the influence of the façade is evaluated for a number of building typologies as a function of the general direction of the incoming sound and of the acoustic absorption coefficient of the surface of the underside of the balcony.

In the paper, the results of a study on the influence of the façade shape on the incoming sound are evaluated with reference to a great number of different typologies of buildings facades. The study has been carried out by means of a prediction software based on the modified theory of the ray tracing (pyramid tracing). Moreover, some of the configurations analyzed with the prediction software have been tested also in a scale model.

With reference to a typical urban configuration, results are expressed as level difference between the simple plane façade and the façade with different kind of shielding.
Introduction of Effective Analysis Methods for Construction Noise Assessment
Authors: Wu Weixiong
Published: April 2011

Construction noise is one of the most disruptive noise sources in New York City. Large-scale projects especially can take more than a decade to complete, and often be located in areas with various sensitive noise receptors. A technological and reliable approach is required for evaluation of the construction noise and its impact in close proximity. This paper addresses construction noise analysis methods and mitigations, along with a case of noise study (i.e., Fordham University Lincoln Center), in accordance with the CEQR Technical Manual requirements and the New York City Noise Control Code regulations. Analysis methods (i.e., screening, detailed, and refined analyses) for construction noise assessment were introduced, and various construction mitigation options (i.e., source, path, and receiver measures) were examined and developed. The results indicated that the analysis methods were effective to assess noise impacts for large complicated construction projects, the mitigation measures were practical, and noise impacts at adjacent sensitive noise receptors were minimized or eliminated. The relevant experiences learned from the study may be beneficial for use of appropriate analysis methods and practical mitigation measures for large-scale construction projects in high-density urban environments.