bluuebunny/crossref_metadata_2025 huggingface dataset:
Chapter 6: Interpreting Scales Through Scale Anchoring
Authors: Beaton Albert E. , Allen Nancy L.
Published: March 2008

The major purpose of the National Assessment of Educational Progress (NAEP) is to provide a means to compare groups of students both across and within assessment years. A complementary purpose of NAEP is to provide information about what these groups of students know and can do. This purpose has been addressed using the scale anchoring techniques described in this chapter. Scale anchoring involves a statistical component that identifies items that discriminate between successive points on the proficiency scale using specific item characteristics. It also involves a consensus component in which identified items are used by subject-area and educational experts to provide an interpretation of what groups of students at or close to the selected scale points know and can do.
Estimation of Effect Size From a Series of Experiments Involving Paired Comparisons
Authors: Gibbons Robert D. , Hedeker Donald R. , Davis John M.
Published: March 2008

This article develops the distribution theory for a Glass-type (1976) estimator of effect size from studies involving paired comparisons. We derive an unbiased estimator of effect size following Hedges’s (1981) work on combining effect sizes from independent samples. It is shown that studies involving mixtures of paired and independent samples can also be combined in this way. Approximate confidence limits for effect size are derived. The method is illustrated using an example from psychiatric research.
Comment on a Wilcox Test Statistic for Comparing Means When Variances Are Unequal
Authors: Hsiung Tung-Hsing , Olejnik Stephen , Huberty Carl J.
Published: March 2008

Wilcox (1989) has proposed an alternative to the James (1951) second-order statistic for comparing population means when variances are heterogeneous. The primary advantage of his approach is its computational simplicity in determining the number of degrees of freedom for the test statistic. We show, however, that the proposed solution can be invalid. With small (but reasonable) sample sizes, population means are underestimated, and mean differences among populations can be overestimated as a result of unequal sample sizes. The degree to which the procedure is invalid depends on the magnitude of the differences in sample sizes, the expected value of the observations, and the population variances.
It’s Déjà Vu All Over Again: Using Multiple-Spell Discrete-Time Survival Analysis
Authors: Willett John B. , Singer Judith D.
Published: March 2008

Multiple-spell discrete-time survival analysis can be used to investigate the repeated occurrence of a single event, or the sequential occurrence of disparate events, including: students’ and teachers’ entries into, and exits from, school; childrens’ progress through stages of cognitive reasoning; disturbed adolescents’ repeated suicide attempts; and so forth. In this article, we introduce and illustrate the method using longitudinal data on exit from, and reentry into, the teaching profession. The advantages of the approach include: (a) applicability to many educational problems; (b) easy inclusion of time-invariant and time-varying predictors; (c) minimal assumptions—no proportional-hazards assumption is invoked and so the effects of predictors can vary over time within, and across, spells; and (d) all statistical models can be fit with a standard logistic regression package.
Identifying Impediments to Learning Probability and Statistics From an Assessment of Instructional Software
Authors: Cohen Steve , Smith George , Chechile Richard A. , Burns Glen , Tsai Frank
Published: March 2008

A detailed, multisite evaluation of instructional software designed to help students conceptualize introductory probability and statistics yielded patterns of error on several assessment items. Whereas two of the patterns appeared to be consistent with misconceptions associated with deterministic reasoning, other patterns indicated that prior knowledge may cause students to misinterpret certain concepts and displays. Misconceptions included interpreting the y-axis on a histogram as if it were a y-axis on a scatter plot and confusing the values a variable might take on by misinterpreting plots of normal probability distributions. These kinds of misconceptions are especially important to consider in light of the increased emphasis on computing and displays in statistics education.
Estimating the Concomitant-Variable Latent-Class Model With the EM Algorithm
Authors: van der Heijden Peter G. M. , Dessens Jos , Bockenholt UIf
Published: March 2008

Latent class analysis assumes the existence of a categorical latent variable that explains the relations between a set of categorical manifest variables. Simultaneous latent class analysis deals with sets of multiway contingency tables simultaneously. In this way an explanatory categorical grouping variable is related to latent class results. In this article we discuss a tool called the concomitant-variable latent-class model, which generalizes this work to continuous explanatory variables. An EM estimation procedure to estimate the model is worked out in detail, and the model is applied to an example on juvenile delinquency.
Dichotomization, Partial Correlation, and Conditional Independence
Authors: Vargha András , Rudas Tamás , Delaney Harold D. , Maxwell Scott E.
Published: March 2008

It was recently demonstrated that performing median splits on both of two predictor variables could sometimes result in spurious statistical significance instead of lower power. Not only is the conventional wisdom that dichotomization always lowers power incorrect, but the current article further demonstrates that inflation of apparent effects can also occur in certain cases where only one of two predictor variables is dichotomized. In addition, we show that previously published formulas claiming that correlations are necessarily reduced by bivariate dichotomization are incorrect. While the magnitude of the difference between the correct and incorrect formulas is not great for small or moderate correlations, it is important to correct the misunderstanding of partial correlations that led to the error in the previous derivations. This is done by considering the relationship between partial correlation and conditional independence in the context of dichotomized predictor variables.
An Application of Gibbs Sampling to Estimation in Meta-Analysis: Accounting for Publication Bias
Authors: Cleary Richard J. , Casella George
Published: March 2008

There is a widespread concern that published results in most disciplines are highly biased in favor of statistically significant outcomes. We propose a model to explicitly account for publication bias using a weight function that describes the probability of publication for a particular study in terms of a selection parameter. A Bayesian analysis of this model using flat priors on both the parameter of interest and the selection parameter is carried out using Gibbs sampling to calculate the posterior distributions of interest. The model is studied in detail for the case of a single observed result and then extended to provide a method for interpreting meta-analyses. We consider models in which the probability of publication for a study might depend on other characteristics of the study—in particular, the size of the study. Finally, we apply our model to a published meta-analysis which examined the effect of coaching on scores on the SAT.
Multiple Testing and Statistical Power With Modified Bonferroni Procedures
Authors: Olejnik Stephen , Li Jianmin , Supattathum Suchada , Huberty Carl J.
Published: March 2008

The difference in statistical power between the original Bonferroni and five modified Bonferroni procedures that control the overall Type I error rate is examined in the context of a correlation matrix where multiple null hypotheses, H0 : ρ ij = 0 for all i ≠ j, are tested. Using 50 real correlation matrices reported in educational and psychological journals, a difference in the number of hypotheses rejected of less than 4% was observed among the procedures. When simulated data were used, very small differences were found among the six procedures in detecting at least one true relationship, but in detecting all true relationships the power of the modified Bonferroni procedures exceeded that of the original Bonferroni procedure by at least .18 and by as much as .55 when all null hypotheses were false. The power difference decreased as the number of true relationships decreased. Power differences obtained for the average power were of a much smaller magnitude but still favored the modified Bonferroni procedures. For the five modified Bonferroni procedures, power differences less than .05 were typically observed; the Holm procedure had the lowest power, and the Rom procedure had the highest.
Controlling Item Exposure Conditional on Ability in Computerized Adaptive Testing
Authors: Stocking Martha L. , Lewis Charles
Published: March 2008

The interest in the application of large-scale adaptive testing for secure tests has served to focus attention on issues that arise when theoretical advances are made operational. One such issue is that of ensuring item and pool security in the continuous testing environment made possible by the computerized admin-istration of a test, as opposed to the more periodic testing environment typically used for linear paper-and-pencil tests. This article presents a new method of controlling the exposure rate of items conditional on ability level in this continuous testing environment. The properties of such conditional control on the exposure rates of items, when used in conjunction with a particular adaptive testing algorithm, are explored through studies with simulated data.
Investigating Local Dependence With Conditional Covariance Functions
Authors: Douglas Jeff , Kim Hae Rim , Habing Brian , Gao Furong
Published: March 2008

The local dependence of item pairs is investigated via a conditional covariance function estimation procedure. The conditioning variable used in the procedure is obtained by a monotonic transformation of total score on the remaining items. Intuitively, the conditioning variable corresponds to the unidimensional latent ability that is best measured by the test. The conditional covariance functions are estimated using kernel smoothing, and a standardization to adjust for the confounding effect of item difficulty is introduced. The particular standardization chosen is an adaptation of Yule’s coefficient of colligation. Several models of local dependence are discussed to explain special situations, such as speededness and latent space multidimensionality, in which the assumptions of unidimensionality and local independence are violated.
Plantar Pressure Analysis After Percutaneous Repair of Displaced Intra-articular Calcaneal Fractures
Authors: Schepers Tim , Van der Stoep Arjan , Van der Avert Hans , Van Lieshout Esther M.M. , Patka Peter
Published: March 2008

Background: Clinical results for the treatment of displaced intra-articular calcaneal fractures are mainly expressed using disease-specific outcome scores, physical examination and radiographs. We hypothesized that plantar pressure and foot position analysis is a valuable tool in assessing foot function in patients with a unilateral displaced intra-articular calcaneal fracture treated percutaneously. Materials and Methods: With a followup of at least one year, 21 patients with a unilateral displaced intra-articular calcaneal fracture treated percutaneously participated in the study. The pedobarographic measurements in the injured foot were compared with the contralateral control foot. Correlations between the ratios (injured/control) of plantar pressure and foot position variables and outcome scores, the physical exam items ratios, the fracture classification, and the radiological parameters were calculated. Results: Statistically significant differences between the injured and the control foot were found for the weight distribution ( p = 0.002), total contact time ( p < 0.001), and the maximum pressure under the first metatarsal ( p = 0.02) after a median followup of 18 months. Of all correlations calculated, only the heel time ratio correlated significantly with the heel width ratio ( p = 0.004). Conclusion: Significant differences in plantar pressure distribution between the injured and uninjured foot were found, indicating that plantar pressure analysis and foot position analysis is an objective test to assess deviations in foot function. Plantar pressure data revealed limited correlation with outcome scores. Therefore, plantar pressure analysis should not be used instead of but in addition to established outcome scores.
Preliminary Experience of a Single Session of Low-energy Extracorporeal Shock Wave Treatment for Chronic Plantar Fasciitis
Authors: Höfling Imke , Joukainen Antti , Venesmaa Petri , Kröger Heikki
Published: March 2008

Background: The purpose of the present study was to evaluate the effect of a single session of ultrasound- and biofeedback-assisted extracorporeal shock wave treatment (ESWT) in patients with chronic plantar fasciitis. Materials and Methods: 20 patients (22 heels) with symptomatic plantar fasciitis that did not respond to conservative treatment for at least 6 months were studied. Patients received a single session of low-energy, ultrasound- and patient feedback-guided ESWT. Visual analog scale (VAS) was used to compare pain intensity before treatment and at followup (72 ± 15 days after treatment). Results: There was a significant decrease in overall pain (VAS 5.5 ± 1.8 vs. 3.3 ± 2.7, p = 0.001), maximum pain (7.7 ± 2.1 vs. 4.0 ± 3.9, p = 0.008) and pain at activities of daily living (5.3 ± 2.1 vs. 2.5 ± 2.6, p = 0.018). Night pain decreased to a lesser extent (2.4 ± 2.5 vs. 1.3 ± 2.1, p = 0.317). ESWT improved symptoms in 16 heels, of which six were completely symptom-free at followup 2.4 months after treatment. Six patients experienced no change. Fourteen patients with pain localized to the heel and all male patients benefited from ESWT. No difference was noted for age, body mass index, duration, and severity of symptoms or previous treatment. Conclusion: Low-energy ESWT proved to be an effective treatment option for the majority of patients with chronic plantar fasciitis that failed to respond to conservative treatment. Predictive parameters for successful outcome are male gender and an easily detectable pain center at the heel.
Increased Displacement Maximizes the Utility of the Distal Chevron Osteotomy for Hallux Valgus Deformity Correction
Authors: Murawski Daniel E. , Beskin James L.
Published: March 2008

Background: Correction of hallux valgus deformity with distal chevron osteotomy is limited by the amount of lateral translation achieved. Since 1999, the senior author has performed a modified technique referred to as increased displacement distal chevron osteotomy in which the distal fragment is translated laterally as far as necessary to obtain correction. This technique can be applied to a deformity with an inter-metatarsal angle of up to 18 degrees. The surgical technique and results of this modified procedure are reported. Materials and Methods: The senior author's (JLB) database was searched for correction of hallux valgus deformity by distal chevron osteotomy performed over a 2-year period. Patients having undergone lateral displacement greater than 50% of the width of the head were studied. At a minimum of two years after surgery, patients were invited to participate in a telephone interview and a final followup office visit. Results: Sixty-two patients underwent 72 procedures during the investigation period. Thirty-three patients having undergone 39 procedures completed comprehensive followup at an average of 34 (range, 24 to 47) months. No patients were dissatisfied and all patients would have surgery again under similar circumstances. AOFAS score averaged 93 with a standard deviation of 8.7 (range, 65 to 100). Radiographic union occurred in all 39 feet. Lateral translation averaged 8.2 mm (60%). No cases of radiographic avascular necrosis or advancement of degenerative joint disease were noted. Correction of the hallux valgus angle (HVA) averaged 22.2 degrees, intermetatarsal angle (IMA) 7.9 degrees, and sesamoid position 1.6 stages. Nine complications were identified in nine feet, two of which required additional surgery. Conclusion: Increasing the displacement achieved with distal chevron osteotomy resulted in reliable correction including moderate to severe deformity. At 2 years, patients displayed a high rate of satisfaction, good clinical outcomes scores, and a complication rate similar to other techniques.
Medial Malleolar Osteotomy for the Correction of Varus Deformity During Total Ankle Arthroplasty: Results in 15 Ankles
Authors: Doets H. Cornelis , van der Plaat Laurens W. , Klein Jan-Paul
Published: March 2008

Background: Preoperative deformity in the frontal plane in the arthritic ankle is a risk factor for failure after total ankle arthroplasty. Medial malleolar lengthening osteotomy was developed to correct varus malalignment. Materials and Methods: From 1998 to 2005 total ankle arthroplasty combined with medial malleolar lengthening osteotomy was done in 15 ankles (13 patients) with a mean preoperative varus deformity of 14.9 (SD, 7.8) degrees. Diagnosis was arthritis with instability in 11 ankles (9 patients) and inflammatory joint disease in 4 ankles. Two mobile-bearing designs were used. Osteosynthesis of the osteotomy was done in 2 ankles; for the remaining 13 osteotomies, no fixation was used. Results: Followup was 5 (range 2 to 8) years. Neutral alignment was obtained in all ankles. In 3 patients residual hindfoot varus remained, for which a second-stage hindfoot correction was done. Two rheumatoid ankles developed a symptom-free nonunion of the medial malleolus, all other malleolar osteotomies united. One tibial component, implanted with too much anterior slope, developed early aseptic loosening and was revised. Debridement for talar-malleolar arthritis was done in two ankles. Of the 14 ankles in followup, 12 were rated as excellent or good, one as fair. One ankle with subsidence of the talar component was rated as unsatisfactory. AOFAS score increased from 30.8 preoperative to 81.0 at followup ( p < 0.01). Conclusion: Medial malleolar lengthening osteotomy is an easy technique for the realignment of the varus ankle at the time of total ankle arthroplasty, and served as an alternative to medial ligament release or lateral ligament reconstruction.
Distally Based Fasciocutaneous Sural Flap for Foot Reconstruction: A Retrospective Review of 10 Years Experience
Authors: Fraccalvieri Marco , Bogetti Paolo , Verna Giovanni , Carlucci Salvatore , Fava Raffaella , Bruschi Stefano
Published: March 2008

Background: The treatment of soft tissue defects of the foot is a problem mainly connected to the thickness of the coverage tissues, to the poor circulation, and to the frequent involvement of muscle, tendon, and bone. The authors present their experience with the sural flap, also in some particular cases. Materials and Methods: The authors treated 33 patients for small- and medium-size defects of the foot, caused by work, home, and road accidents, and by venous or diabetic ulcers. In all cases, the flap was cut in its fasciocutaneous variant; an extension of the sole portion of fascia was added in 5 patients. The flap was transferred under a subcutaneous tunnel in 10 cases, with an open incision in 20 cases, and in 3 cases the pedicle was kept external for 4 weeks, then resected. Results: One patient showed a complete necrosis of the flap and another showed a superficial necrosis preserving the deep fascia; in the remaining 31 cases, the flap incorporated without any major complication. The flap provided proper coverage of the defects from both an aesthetic and functional point of view as evidenced clinically and through a baropedographic test. Conclusion: The advantages of this flap include: dissection is fast and easy, it is not necessary to sacrifice important arterial pedicle or muscular units as it can be used in traumatized limbs without further damage to main arteries, and a wide rotation arc is possible. Disadvantages include the sacrifice of the sural nerve and the covering of the donor region with skin grafts.
Weightbearing CT Scan of Severe Flexible Pes Planus Deformities
Authors: Ferri Melanie , Scharfenberger Angela V. , Goplen Gord , Daniels Timothy R. , Pearce Dawn
Published: March 2008

Background: The three-dimensional relationships of the bones in the foot in a flatfoot deformity are difficult to assess with standard radiographs. CT scans demonstrate these relationships but are typically made in a nonweightbearing mode. Our objective was to assess the use of a weightbearing CT apparatus to image the feet in patients with severe flexible pes planus deformities and to better define the anatomical changes that occur. Materials and Methods: A specialized device was designed and constructed to simulate weightbearing to the feet during CT examination. Eighteen normal feet and 30 painful severe and flexible pes planus feet were imaged in both the non weightbearing and weightbearing states, set at 50% of body weight. Several measurements of intertarsal relationships were made of the pes planus and normal feet. Navicular floor to skin distance, forefoot arch angle, and subtalar joint subluxation were measured in the coronal plane in both the weightbearing and nonweightbearing states. T-tests were used to analyze measurements of navicular floor to skin distance and forefoot arch angle. Results: The weightbearing device had a significant effect on foot configuration for both normal and pes planus feet ( p = 0.0008) and ( p < 0.0001) respectively for both floor to skin distance and forefoot arch angle. There was a significant difference between normal feet and pes planus feet with regard to the forefoot arch angle in the nonweightbearing ( p = 0.02) and weightbearing states ( p = 0.01). Four of the pes planus patients had evidence of subtalar joint subluxation which was more pronounced in the weightbearing state. There was no significant difference between the navicular floor to skin distance in the normal versus pes planus feet in either the non weightbearing ( p = 0.05) or the weightbearing states ( p = 0.07). Conclusion: A device was designed and constructed to apply a weightbearing load equal to that of 50% body weight with minimal to no patient discomfort. The resultant effects on foot configuration were significant, and are useful for assessment of degree of flexible flat foot deformity, thus guiding clinical management. The measure which most significantly differed between pes planus patients and normal volunteers was the forefoot arch angle. Forefoot arch angle may therefore be the most useful measure for the imaging diagnosis of flexible pes planus, and the degree of planus deformity.
In-vitro Comparison of Biomechanical Efficiency of Three Cannulated Screws for Arthrodesis of the Hindfoot
Authors: Huber Wolfgang O. , Reihsner Roland , Trieb Klemens , Wanivenhaus Axel Hugo , Beer Rudolf
Published: March 2008

Background: Sufficient inter-fragmentary compression is helpful to achieve successful bony fusion in hindfoot arthrodesis using internal fixation by screws. Beside bone quality, the design of a screw influences inter-fragmentary compression. Compressive force is achievable for any kind of screw system; however, the primary deformation of the bone is different for the different screw systems. The work necessary to achieve compressive force for primary stability was measured for different screw systems and compared to an AO screw with washer. Materials and Methods: The compressive force was determined as a function of screw advancement for 3 different cannulated screw types (7.3-mm AO screw with and without washer, the 6.5mm Herbert screw and the 6.5-mm Ideal Compression Screw (I.CO.S) using different synthetic bone density (0.16, 0.24, 0.48 g/ccm). Compressive force was measured indirectly, via screw tension measurement with strain gauges. Results: We calculated the work to reach a limit of 60 N and the corresponding ratios to the value of the golden standard: I.CO.S (35.2%), Herbert (89.0%), AO screw without washer (116%). Conclusion: All screw systems yielded acceptable results but the ICOS did produce greater compresion. The essential differences were the primary deformation of the bone before reaching the sufficient compressive force for primary stability.
Surgical Treatment of AVN of the Fibular (Lateral) Sesamoid
Authors: Waizy Hazibullah , Jäger Marcus , Abbara-Czardybon Mona , Schmidt Troy G. , Frank Daniel
Published: March 2008

Despite the fact that the hallucal sesamoids play a crucial role in forefoot mechanics, disorders resulting from pathology of these structures are often overlooked or misdiagnosed. Avascular necrosis (AVN) of the hallucal sesamoids is a rare condition that must be differentiated from other pathologies, such as fractures, pseudarthrosis or osteomyelitis. We report on two patients with AVN of the fibular (lateral) hallucal sesamoid (Morbus Renander). In both patients the necrotic part of the fibular sesamoid was excised surgically after failed conservative therapy. The followup was 29 and 26 months. The clinical and radiological results showed a complete relief of pain in both patients without any complications or forefoot deformities. Recent literature and own experiences support non-operative initial management including anti-inflammatory medications, shoe modification and temporary limited weight bearing. If symptoms persist, surgical treatment with excision of the necrotic part of the sesamoid may be an alternative. Consideration by the surgeon should be given to protecting the neurovascular bundle and reattaching intrinsic tendons and ligaments if necessary. Satisfying results can be achieved by surgical removal.
Secretan's Disease of the Foot: A Case Report and Review
Authors: Abnousi Freddy , Chou Loretta B.
Published: March 2008

Secretan's disease is a rare disorder that has, to date, only been reported in the hand. After minor trauma, edema and hyperplasia of the hand may result, and pathological evaluation demonstrates thick fibrous tissue. We present the first report of Secretan's disease involving the foot in a 15-year-old athletic teenage girl with a remote history of blunt trauma, and review the relevant literature.
Current Concepts Review: Total Ankle Arthroplasty
Authors: Guyer Aaron J. , Richardson E. Greer
Published: March 2008

Many orthopaedic surgeons had abandoned the use of first and second generation total ankle arthroplasties due to unacceptably high complication and failure rates as compared to arthrodesis. Recently, there has been renewed interest in ankle joint replacement as longer term outcome studies have become available, and the FDA has approved several more designs. With the introduction of two new FDA approved implants in November 2006, options for surgeons interested in total ankle arthroplasty have greatly expanded. There continues to be much debate within the orthopaedic community as to indications, patient selection, and optimal component design. This review aims to provide orthopaedists with an overview of the currently available implants and literature.
Development of the Science of Catalysis
Authors: Davis Burtron H.
Published: March 2008

The sections in this article are

Early Concepts: Berzelius, Liebig, and Faraday

Wilhelm Ostwald

The Concepts of Kinetics and Intermediate Compounds

Negative Catalysis: Autocatalysis

Adsorption

Active Site: Geometric or Electronic?

Selected Systems

Ammonia Synthesis

Acid Catalysis

Zeolites

Ions in Catalysis

Hydrogenation

Oxidation
The Development of Industrial Heterogeneous Catalysis
Authors: Dingerdissen Uwe , Martin Andreas , Herein Daniel , Wernicke Hans Jürgen
Published: March 2008

The sections in this article are

Introduction

The Raw Materials Situation

Inorganic Base Chemicals

Petroleum Refining

Coal and Natural Gas Processing

The Base Chemicals

Olefins and Aromatics

Alcohols, Ethers, Aldehydes, and Ketones

Alcohols

Methanol

Ethanol

2‐Propanol

Ethers

Aldehydes

Acids, Esters, Anhydrides, and Epoxides

Acids, Esters, Anhydrides

Acetic Acid

Epoxides

Halogenated Chemicals

The Fine Chemicals

Catalytic Hydrogenation

Hydrogenation of Carbon–Carbon Multiple Bonds

Hydrogenation of Carbon–Oxygen and Carbon–Nitrogen Multiple Bonds

Reductive Amination

Nitrile Hydrogenation

Hydrogenation of Nitro Groups

Catalysis on Solid Acids and Bases

Aromatic Substitution (Friedel–Crafts Alkylation and Acylation)

Amination

Rearrangement, Isomerization

Oxidation Catalysis

Oxidation of Alcohols and Aldehydes

Epoxidation and Aromatic Ring Hydroxylation

Environmental Catalysis

Cleaning of Automobile Emissions

Removal of Harmful Emissions from Stationary Sources

Wastewater Treatment

Fuel Cell Catalysis

Photocatalytic Applications
Fused Catalysts
Authors: Schlögl Robert
Published: March 2008

The sections in this article are

Introduction

The Concept of Fused Catalysts

Thermodynamic and Kinetic Considerations

Sulfuric Acid Catalyst

Metallic Glasses

Tribochemistry

Mesostructure of Fused Catalyst Materials
Skeletal Metal Catalysts
Authors: Smith Andrew James , Wainwright Mark Sebastian
Published: March 2008

The sections in this article are

Introduction

General Aspects

Alloy Preparation

Activation Using Alkali Leaching

Storage and Handling

Advantages of Skeletal Metal Catalysts

Skeletal Nickel Catalysts

Alloy Preparation of Skeletal Nickel Catalysts

Properties of Skeletal Nickel Catalysts

Uses of Skeletal Nickel Catalysts

The Promotion of Skeletal Nickel Catalysts

Skeletal Copper Catalysts

Alloy Preparation of Skeletal Copper Catalysts

Properties of Skeletal Copper Catalysts

Uses of Skeletal Copper Catalysts

Promotion of Skeletal Copper Catalysts

Skeletal Cobalt Catalysts

Other Skeletal Metal Catalysts
Precipitation and Coprecipitation
Authors: Schüth Ferdi , Hesse Michael , Unger Klaus K.
Published: March 2008

The sections in this article are

Introduction

General Principles Governing Precipitation from Solutions

Physico‐Chemical Considerations

Chemical Considerations

Process Considerations

Influencing the Properties of the Final Product

Influence of Raw Materials

Influence of Concentration and Composition

Solvent Effects

Influence of Temperature

Influence of
p
H

Influence of Aging

Influence of Additives

Prototypical Examples of Precipitated Catalysts and Supports

Silica as Support Material

Active Aluminas

Ni
/Al
2
O
3
Catalysts by Coprecipitation

V
/
P
/
O
Catalysts for Butane Oxidation to Maleic Anhydride

Conclusions
Hydrothermal Zeolite Synthesis
Authors: Kirschhock Christine E. A. , Feijen Eddy J. P. , Jacobs Pierre A. , Martens Johan A.
Published: March 2008

The sections in this article are

Introduction

Zeolitization in General

Key Steps in Zeolite Synthesis

Key Parameters Governing Zeolitization

A
Molar Composition

B
Mineralizing Agent

C
Temperature and Time

Precursor Species

Templates

A
Charged Molecules

B
Neutral Molecules

C
Ion Pairs

Rationalization of Crystallization Conditions for Zeolites
A
,
X
,
Y
, and
EMC
‐2

Zeolite Growth Models

A
The Nucleation and Growth Process

a 
Achievement of Supersaturation

b 
Nucleation

c 
Crystal Growth

d 
Seeding

B
The Aggregation Model

Synthesis of Industrial Zeolites

Industrial Zeolites Crystallized from the Na
2
O‐Al
2
O
3
‐SiO
2
‐H
2
O System: Zeolites
A
,
X
,
Y
, Mordenite, and
ZSM
‐5

Industrial Zeolite Crystallization in the Presence of Organic Compounds

Conclusions and Outlook

Acknowledgments
Ordered Mesoporous Materials
Authors: Kleitz Freddy
Published: March 2008

The sections in this article are

Introduction

Ordered Mesoporous Molecular Sieves:MCM‐41

Synthesis of Ordered Mesoporous Materials

Synthesis Strategies for Mesostructure Formation

Inorganic Polymerization and Self‐Assembly with Surfactants

A Inorganic Polymerization (the Case of Silica)

B Template‐Assisted Synthesis

C Surfactant Packing

D Formation of the Mesostructure

E True Liquid Crystal Templating

F Evaporation‐Induced Self‐Assembly

Synthesis Pathways and Structural Diversity

A Silica Polymorphs from the Alkaline Route (S+I−)

B Silica Polymorphs from the Acidic Route (S+X−I+)

C Anionic Surfactant‐Templated Mesoporous Silicas: AMS‐nMaterials

D Non‐Ionic Routes (Hydrogen‐Bonding InteractionsS0I0,N0I0or (N0H+) (X−I+)

Pore Size Tailoring and Structure Engineering

A Surfactant Chain Length

B Time and Temperature

C Effects of Electrolytes and pH Adjustment

D Organic Additives

E Stability and Zeolitization

Removal of the Template

A Calcination

B Solvent Extraction and Acid Treatments

Functionalization of Ordered Mesoporous Materials

Functionalization Strategies

Surface Properties

Surface Functionalization

Framework Functionalization

Non‐Siliceous Mesostructured and Mesoporous Materials

Transition Metal Oxides

Alumina

Other Non‐Siliceous Compositions

Hard Templating (Nanocasting)

Morphology Control

Concluding Remarks
Pillared Clays
Authors: Poncelet Georges , Fripiat José J.
Published: March 2008

The sections in this article are

Introduction

Historical Overview

Which Clays or Smectites can be Pillared?

Al‐Pillared Vermiculites and Phlogopite Micas

Reviews

Pillaring Mechanisms

Basic Pillaring Mechanism: Exchange Precipitation

New Pillaring Mechanism: Template

Pillars

Homo‐Atomic Pillars

AHydroxyaluminum Polymer

BGallium and Mixed Gallium Aluminum Hydroxypolymers

CZirconia Hydroxypolymers

DTitania Pillars

ESilica and Silicate Pillars

FTransition Metal Oxide Pillars

Heteroatomic Pillars

MixedAlFePillars

Miscellaneous

Pillared Clays

Preliminary Remarks

Main Physical Characteristics

Chemical Properties

Chemical Modifications or Functionalization of the Pillaring Species

Catalytic Properties

A Brief Summary of Previous Studies

An Overview of Catalytic Reactions Investigated during the Past Decade

Conclusions

Acknowledgments
Chemistry and Applications of Porous Metal–Organic Frameworks
Authors: Müller Ulrich , Schubert Markus M. , Yaghi Omar M.
Published: March 2008

The sections in this article are

Introduction

Terminology and Structure

Synthesis

Characterization

Emerging Applications

Adsorption Properties

Diffusional Properties

Gas Purification

Gas Separation

Gas Storage

Catalysis

Conclusions
Catalysis by Ion‐Exchange Resins
Authors: Gates Bruce C.
Published: March 2008

The sections in this article are

Introduction

Classes of Ion‐Exchange Resin Catalysts: The Importance of Porosity

Examples of Industrial Catalysis by Ion‐Exchange Resins

Synthesis of Ion‐Exchange Resins

Structure, Influence of Water, and Acidity in Ion‐Exchange Resins

Accessibility, Swelling, and Mass Transfer Effects

Mechanisms of Reactions Catalyzed by Sulfonic Acid Resins

Kinetics of Reactions Catalyzed by Ion‐Exchange Resins

Deactivation and Stability of Ion‐Exchange Resin Catalysts

Modified and Metal‐Containing Ion‐Exchange Resin Catalysts

Hybrid Organic/Inorganic Catalysts akin to Ion‐Exchange Resins

Summary and Outlook

Acknowledgments
Flame Hydrolysis
Authors: Kerner Dieter , Rochnia Matthias
Published: March 2008

The sections in this article are

Manufacture of Pyrogenic Oxides

Physico‐Chemical Properties of Pyrogenic Oxides

Preparation of Formed Supports

Applications

Conclusions
Transition Metal Carbides, Nitrides, and Phosphides
Authors: Oyama S. Ted
Published: March 2008

The sections in this article are

Introduction

General Properties

Structure

Binary Compounds of
C
and
N

Binary Compounds of Phosphorus

Preparation

The Reactions of Metals or Metal Compounds with Gas‐Phase Reagents

Decomposition of Metal Halide Vapors

Decomposition of Metal Compounds

Temperature‐Programmed Methods

Utilization of High‐Surface‐Area Supports

Reaction Between Metal Oxide Vapor and Solid Carbon

Liquid‐Phase Methods

Amorphous Materials

Catalytic Properties

Acid and Base Catalysis

Ammonia Synthesis and Decomposition

Aromatization

Hydrogenation and Dehydrogenation

Hydrotreating

Isomerization and Hydroisomerization (Reforming)

Methanation and
F
ischer–
T
ropsch

Oxidation

Reforming (Steam, Dry, and Autothermal)

Water‐Gas Shift and Reverse Water‐Gas Shift

Perspective
Solid‐State Ion Exchange in Zeolites
Authors: Karge Hellmut G.
Published: March 2008

The sections in this article are

Introduction

Comparison of Conventional and Solid‐State Ion Exchange

Experimental Procedure for Solid‐State Ion Exchange in Zeolites

Methods of Monitoring Solid‐State Ion Exchange

Infrared Spectroscopy

ESRSpectroscopy

Mössbauer Spectroscopy

Solid‐StateNMRSpectroscopy

X‐Ray Diffraction

ExtendedX‐Ray Absorption Fine Structure (EXAFS) andX‐Ray Absorption Near Edge Structure (XANES)

Temperature‐Programmed Evolution (TPE) of Volatile Gases

Thermogravimetric Analysis (TGA)

Systems Investigated for Solid‐State Ion Exchange in Zeolites

Solid‐State Ion Exchange with Salts of Alkaline Metals

Solid‐State Ion Exchange with Salts of Alkaline Earth Metals

Solid‐State Ion Exchange with Salts of Lanthanum

Solid‐State Ion Exchange with Salts of Copper

Solid‐State Ion Exchange with Salts of Iron

Solid‐State Ion Exchange with Salts of Manganese

Solid‐State Ion Exchange with Salts of Noble Metals

Miscellaneous

Some Considerations on Thermodynamic and Kinetic Aspects ofSSIE

Effect of Temperature and Salt Concentration in Salt/Zeolite Mixtures

The Role of Water in Solid‐State Ion Exchange

Kinetics of Solid‐State Ion Exchange

A Possible Mechanism of Solid‐State Ion Exchange

Modified Solid‐State Ion Exchange and Related Processes

Contact‐Induced Ion Exchange

Incipient Wetness Technique of Impregnation

Gas‐Phase‐Mediated Processes Related to Solid‐State Ion Exchange

Oxidative and Reductive Solid‐State Ion Exchange

A Tabulated Survey of the Systems Studied inSSIEand Related Processes

Concluding Remarks
Spreading and Wetting
Authors: Knözinger Helmut , Taglauer Edmund
Published: March 2008

The sections in this article are

Introduction

Theoretical Considerations

Thermodynamics of Wetting and Spreading

Qualitative Discussion of the Dynamics of Interfacial Processes

Supported Metal Catalysts

Sintering and Redispersion

Strong Metal Support Interactions (SMSI)

Bimetallic Catalysts

Supported Oxide Catalysts

Molybdenum‐Based Catalysts

Vanadium‐Based Catalysts

Tungsten‐Based Catalysts

Zeolites as Supports

Solid‐State Ion Exchange of Zeolites
Zeolite‐Entrapped Metal Complexes
Authors: Ernst Stefan
Published: March 2008

The sections in this article are

Introduction

Synthesis of Zeolite‐Entrapped Metal Complexes

Flexible‐Ligand Method

Ship‐in‐the‐Bottle Method

Zeolite Synthesis Method

Characterization

Electron Paramagnetic Resonance Spectroscopy

Electron Excitation by Ultraviolet/Visible Light

X‐Ray Photoelectron Spectroscopy

Infrared Spectroscopy

Nuclear Magnetic Resonance Spectroscopy

R
aman Spectroscopy

Stability Analysis

Oxygen Adsorption

Cyclovoltammetry

Catalysis by Zeolite‐Entrapped Transition Metal Complexes

Selective Oxidations on Zeolite‐Encaged Transition Metal Complexes

Selective Hydrogenations on Zeolite‐Encaged Transition Metal Complexes

Catalysis by Zeolite‐Encapsulated Chiral Complexes

Miscellaneous Reactions

Conclusions

Acknowledgments
Immobilization of Biological Catalysts
Authors: Ansorge‐Schumacher Marion B.
Published: March 2008

The sections in this article are

Introduction

Immobilization by Attachment

Carrier‐Less Crosslinking

Adsorption onto a Carrier

Covalent Binding to a Carrier

Immobilization by Entrapment

Entrapment in a Matrix

Entrapment in Membranes

Conclusion
Reactions During Catalyst Activation
Authors: Delmon Bernard
Published: March 2008

The sections in this article are

Introduction

Particular Features of Chemical Reactions of Supported Solids

Characteristics of Reactions of Solids: Possible Consequences in the Kinetics of Activation

Interface‐Controlled (
IC
) Reactions

Interaction Between Supported Phases and Supports

Case 1: Very Weak Forces

Case 2: Electronic Interaction

Cases 3 to 7: Attachment Through a Transition Layer

Case 8: Grafted Precursors

Intermediate Cases

Activation of Supported Catalysts by Calcination

Activation of Supported Catalysts by Reduction

General: Effect of Precursor Dispersion

Overall Effects: Influence of Calcination Temperature in Precursor Preparation

Role of Precursors

Influence of the Amount of Deposited Precursor Loaded on the Support

Effect of the Formation of Compounds between the Precursor and the Support

Nature of the Support

Effect of Modifiers (Promotors)

Influence of the Activation Conditions

Final Remarks

Reduction–Sulfidation

Fundamental Data

Influence of the Sequence of Steps in Reduction‐Sulfidation

Influence of the Activation Temperature

Influence of the Sulfiding Molecule

Other Results

Outlook

Activation of Other Catalysts

Conventional Activation and the Real State of Catalysts during Catalysis

Conclusions
Zeolite Standard Catalysts and Related Activities of the International Zeolite Association
Authors: Stöcker Michael , Weitkamp Jens
Published: March 2008

The sections in this article are

Introduction

Atlas of Zeolite Framework Types

Verified Syntheses of Zeolitic Materials

Preparation of the Standard Large‐Pore, Acidic Zeolite Catalyst
La
,
Na
‐
Y

Apparatus and Procedure for Catalyst Testing

Comparison of the Results Achieved in Five Different Laboratories

Conclusions
Surface Area and Porosity
Authors: Neimark Alexander V. , Sing Kenneth S. W. , Thommes Matthias
Published: March 2008

The sections in this article are

Introduction

Physisorption of Gases

Determination of Surface Area

ATheBETMethod

BThe Standard Isotherm Concept

Assessment of Porosity

ACapillary Condensation and the Kelvin Equation

BAdsorption Hysteresis

CMicroporosity

DMicropore Analysis: Dubinin's Theory of Micropore Filling

EMicropore Analysis: Empirical Methods

FOther Methods for Micropore Pore Size Analysis

GApplication of Density Functional Theory

Adsorption at the Liquid–Solid Interface

Adsorption from Solution

Heat of Immersion

Mercury Porosimetry

General Conclusions
Particle Size and Dispersion Measurements
Authors: Bergeret Gérard , Gallezot Pierre
Published: March 2008

The sections in this article are

Definitions and Generalities

Particles

Particle Size

Nuclearity of Particles

Dispersion

Relationships Between Particle Size, Surface Area and Dispersion

Methods of Particle Size Measurement

Particle Size Measurements by Gas Chemisorption

Introduction and Principles

Gas Adsorption–Desorption Methods

AStatic Methods

BDynamic Methods

CDesorption Methods

Choice of Adsorbate Gases

Hydrogen Chemisorption; HydrogenOxygen Titration

Conclusion and Recommendations

X‐Ray Diffraction Line Broadening Analysis

Introduction

Elementary Line Broadening Analysis: the Scherrer Equation

Complete Line Profile Analysis: theWarren–Averbach Method

Examples of Application of ClassicalLBAto Catalysts

Whole‐Powder Pattern Fitting Methods: the Rietveld Refinement

Limits of Application of Methods

Conclusion

Small‐AngleX‐Ray Scattering Analysis

Introduction

Specific Surface Area Measurements:Porod's Law

Mean Size Parameters: Guinier Radius

Calculation of Size Distribution

Application ofSAXSto Metal Particle Size Determination in Supported Catalysts

Anomalous Small‐AngleX‐Ray Scattering (ASAXS)

Conclusion

Determination of Particle Size by Electron Microscopy

Scope

Fundamentals of Imaging and Contrast

ATransmission Electron Microscope

BScanning Transmission Electron Microscope

CScanning Electron Microscope

Preparation of Samples forTEMandSTEMExamination

Particle Size Measurement

Selected Examples of Particle Size Distribution

Selected Examples of 3D Localization of Particles in Supports by Electron Tomography

Particle Size Measurements by Magnetic Methods
X‐Ray Powder Diffraction
Authors: Herein Daniel
Published: March 2008

The sections in this article are

Introduction

Phase Analysis

Peak Profile Analysis

Full X‐Ray Powder Pattern Analysis

In SituX‐Ray Powder Diffraction

Conclusion
Scanning Probe Techniques
Authors: Besenbacher Flemming , Lauritsen Jeppe Vang , Vang Ronnie T.
Published: March 2008

The sections in this article are

Introduction

Scanning Probe Techniques

High‐ResolutionSTMStudies

Dynamic Imaging

High‐PressureSTMStudies

Imaging of Oxide Surfaces

Catalyst Design Based on Model System Studies

Conclusion

Acknowledgements
Heterogeneous Catalysis and High Electric Fields
Authors: Kruse Norbert , de Bocarmé Thierry Visart
Published: March 2008

The sections in this article are

Introduction

Electric Fields

Applications in Fundamental Research on Heterogeneous Catalysis

Field‐Induced Surface Phenomena

Field‐Induced Phenomena at Extended Surfaces and Interfaces

Conclusion
Mechanical Properties
Authors: Schmidt Friedrich
Published: March 2008

The sections in this article are

Introduction

General Considerations

Causes of Mechanical Damage

Mechanical Resistance of Catalysts—Definitions

Determination of Crush Strength (Break Strength)

Crush Strength of Individual Grains

Bulk Crush Strength (Bed Crushing Strength) or Shell Test

Impact or Drop Test

Determination of Attrition Resistance

Grains or Powders

Attrition Resistance of Coated Monoliths

Adhesiveness of Coatings
Thermochemical Characterization
Authors: Cardona Martínez Nelson , Dumesic James A.
Published: March 2008

The sections in this article are

Introduction

Principles of Temperature‐Programmed Desorption

Applications of Temperature‐Programmed Desorption

Principles of Adsorption Microcalorimetry

Applications of Adsorption Microcalorimetry

Conclusions
Infrared Spectroscopy for the Characterization of Surface Acidity and Basicity
Authors: Knözinger Helmut
Published: March 2008

The sections in this article are

Introduction

Criteria for the Selection of Probe Molecules

Characterization of Acid Sites on Solid Catalysts

Characterization of Basic Sites on Solid Catalysts

Conclusion
Oxide–Support Interactions
Authors: Bergwerff Jaap A. , Weckhuysen Bert M.
Published: March 2008

The sections in this article are

Acknowledgments
Reporting Physisorption Data for Gas/Solid Systems
Authors: Sing Kenneth S. W. , Everett Douglas H. , Haul R. A. W. , Moscou L. , Pierotti Robert A. , Rouquerol Jean , Siemieniewska Teresa
Published: March 2008

The sections in this article are

Introduction

General Definitions and Terminology

Methodology

Methods for the Determination of Adsorption Isotherms

Operational Definitions of Adsorption

Experimental Procedures

Outgassing the Adsorbent

Determination of the Adsorption Isotherm

Evaluation of Adsorption Data

Presentation of Primary Data

Classification of Adsorption Isotherms

Adsorption Hysteresis

Determination of Surface Area

Application of the
BET
Method

Empirical Procedures for Isotherm Analysis

Assessment of Mesoporosity

Properties of Porous Materials

Application of the
K
elvin Equation

Computation of Mesopore Size Distribution

Assessment of Microporosity

Terminology

Concept of Surface Area

Assessment of Micropore Volume

General Conclusions and Recommendations
Metallic Glasses
Authors: Baiker Alfons , Molnár Árpád
Published: March 2008

The sections in this article are

Introduction

Preparation

Chemical and Structural Properties

Metallic Glasses in Catalysis Research

Research into Metallic Glasses in As‐Quenched State

Metallic Glasses as Precursors to Catalytically Active Materials

Factors Influencing Chemical and Structural Properties of Catalytic Materials Derived from Metallic Glasses

Chemical Composition

Chemical and Structural Homogeneity

Thermal Stability and Crystallization Behavior

Oxidation Behavior

Dissolution of Gases

Segregation Phenomena

Case Studies

CO
Oxidation Catalysts Prepared from Metallic Glasses

Pd
/
ZrO
2
Catalysts from Amorphous
Pd

Zr
Alloys

Promoted
Au

Zr
Catalysts from Ternary
Au
‐Containing Glassy Alloys

Methanation over
Ni
Alloys

Dehydrogenation over
Cu

M
(
Ti
,
Zr
or
Hf
) Catalysts

Conclusions and Outlook
Bimetallic Model Catalysts
Authors: Rodriguez José A.
Published: March 2008

The sections in this article are

Introduction

Structure of Bimetallic Surfaces

Electronic Properties of Bimetallic Surfaces

Chemical and Catalytic Properties of Bimetallic Surfaces

Conclusions

Acknowledgments