Virtual tissue alignment and cutting plane definition--a new method to obtain optimal longitudinal histological sections.

Histomorphometric evaluation of the buccal aspects of periodontal tissues in rodents requires reproducible alignment of maxillae and highly precise sections containing central sections of buccal roots; this is a cumbersome and technically sensitive process due to the small specimen size. The aim of the present report is to describe and analyze a method to transfer virtual sections of micro-computer tomographic (CT)-generated image stacks to the microtome for undecalcified histological processing and to describe the anatomy of the periodontium in rat molars. A total of 84 undecalcified sections of all buccal roots of seven untreated rats was analyzed. The accuracy of section coordinate transfer from virtual micro-CT slice to the histological slice, right-left side differences and the measurement error for linear and angular measurements on micro-CT and on histological micrographs were calculated using the Bland-Altman method, interclass correlation coefficient and the method of moments estimator. Also, manual alignment of the micro-CT-scanned rat maxilla was compared with multiplanar computer-reconstructed alignment. The supra alveolar rat anatomy is rather similar to human anatomy, whereas the alveolar bone is of compact type and the keratinized gingival epithelium bends apical to join the junctional epithelium. The high methodological standardization presented herein ensures retrieval of histological slices with excellent display of anatomical microstructures, in a reproducible manner, minimizes random errors, and thereby may contribute to the reduction of number of animals needed.

Computer planned, image-guided combined resection and ablation for bilobar colorectal liver metastases

For patients with extensive bilobar colorectal liver metastases (CRLM), initial surgery may not be feasible and a multimodal approach including microwave ablation (MWA) provides the only chance for prolonged survival. Intraoperative navigation systems may improve the accuracy of ablation and surgical resection of so-called "vanishing lesions", ultimately improving patient outcome. Clinical application of intraoperative navigated liver surgery is illustrated in a patient undergoing combined resection/MWA for multiple, synchronous, bilobar CRLM. Regular follow-up with computed tomography (CT) allowed for temporal development of the ablation zones. Of the ten lesions detected in a preoperative CT scan, the largest lesion was resected and the others were ablated using an intraoperative navigation system. Twelve months post-surgery a new lesion (Seg IVa) was detected and treated by trans-arterial embolization. Nineteen months post-surgery new liver and lung metastases were detected and a palliative chemotherapy started. The patient passed away four years after initial diagnosis. For patients with extensive CRLM not treatable by standard surgery, navigated MWA/resection may provide excellent tumor control, improving longer-term survival. Intraoperative navigation systems provide precise, real-time information to the surgeon, aiding the decision-making process and substantially improving the accuracy of both ablation and resection. Regular follow-ups including 3D modeling allow for early discrimination between ablation zones and recurrent tumor lesions.

Real-time computer-based visual feedback improves visual acuity in downbeat nystagmus - a pilot study.

BACKGROUND Patients with downbeat nystagmus syndrome suffer from oscillopsia, which leads to an unstable visual perception and therefore impaired visual acuity. The aim of this study was to use real-time computer-based visual feedback to compensate for the destabilizing slow phase eye movements. METHODS The patients were sitting in front of a computer screen with the head fixed on a chin rest. The eye movements were recorded by an eye tracking system (EyeSeeCam®). We tested the visual acuity with a fixed Landolt C (static) and during real-time feedback driven condition (dynamic) in gaze straight ahead and (20°) sideward gaze. In the dynamic condition, the Landolt C moved according to the slow phase eye velocity of the downbeat nystagmus. The Shapiro-Wilk test was used to test for normal distribution and one-way ANOVA for comparison. RESULTS Ten patients with downbeat nystagmus were included in the study. Median age was 76 years and the median duration of symptoms was 6.3 years (SD +/- 3.1y). The mean slow phase velocity was moderate during gaze straight ahead (1.44°/s, SD +/- 1.18°/s) and increased significantly in sideward gaze (mean left 3.36°/s; right 3.58°/s). In gaze straight ahead, we found no difference between the static and feedback driven condition. In sideward gaze, visual acuity improved in five out of ten subjects during the feedback-driven condition (p = 0.043). CONCLUSIONS This study provides proof of concept that non-invasive real-time computer-based visual feedback compensates for the SPV in DBN. Therefore, real-time visual feedback may be a promising aid for patients suffering from oscillopsia and impaired text reading on screen. Recent technological advances in the area of virtual reality displays might soon render this approach feasible in fully mobile settings.

Computer-Assisted Orthopedic Surgery: Current State and Future Perspective

Introduced about two decades ago, computer-assisted orthopedic surgery (CAOS) has emerged as a new and independent area, due to the importance of treatment of musculoskeletal diseases in orthopedics and traumatology, increasing availability of different imaging modalities, and advances in analytics and navigation tools. The aim of this paper is to present the basic elements of CAOS devices and to review state-of-the-art examples of different imaging modalities used to create the virtual representations, of different position tracking devices for navigation systems, of different surgical robots, of different methods for registration and referencing, and of CAOS modules that have been realized for different surgical procedures. Future perspectives will also be outlined.

Computer Assisted Diagnosis and Treatment Planning of Femoroacetabular Impingement (FAI)

Femoroacetabular impingement (FAI) is a dynamic conflict of the hip defined by a pathological, early abutment of the proximal femur onto the acetabulum or pelvis. In the past two decades, FAI has received increasing focus in both research and clinical practice as a cause of hip pain and prearthrotic deformity. Anatomical abnormalities such as an aspherical femoral head (cam-type FAI), a focal or general overgrowth of the acetabulum (pincer-type FAI), a high riding greater or lesser trochanter (extra-articular FAI), or abnormal torsion of the femur have been identified as underlying pathomorphologies. Open and arthroscopic treatment options are available to correct the deformity and to allow impingement-free range of motion. In routine practice, diagnosis and treatment planning of FAI is based on clinical examination and conventional imaging modalities such as standard radiography, magnetic resonance arthrography (MRA), and computed tomography (CT). Modern software tools allow three-dimensional analysis of the hip joint by extracting pelvic landmarks from two-dimensional antero-posterior pelvic radiographs. An object-oriented cross-platform program (Hip2Norm) has been developed and validated to standardize pelvic rotation and tilt on conventional AP pelvis radiographs. It has been shown that Hip2Norm is an accurate, consistent, reliable and reproducible tool for the correction of selected hip parameters on conventional radiographs. In contrast to conventional imaging modalities, which provide only static visualization, novel computer assisted tools have been developed to allow the dynamic analysis of FAI pathomechanics. In this context, a validated, CT-based software package (HipMotion) has been introduced. HipMotion is based on polygonal three-dimensional models of the patient’s pelvis and femur. The software includes simulation methods for range of motion, collision detection and accurate mapping of impingement areas. A preoperative treatment plan can be created by performing a virtual resection of any mapped impingement zones both on the femoral head-neck junction, as well as the acetabular rim using the same three-dimensional models. The following book chapter provides a summarized description of current computer-assisted tools for the diagnosis and treatment planning of FAI highlighting the possibility for both static and dynamic evaluation, reliability and reproducibility, and its applicability to routine clinical use.

WOCAT - World Overview of Conservation Approaches and Technologies - Preliminary results from Eastern and Southern Africa

The World Overview of Conservation Approaches and Technologies (WOCAT) is a program of the World Association of Soil and Water Conservation (WASWC), organized as a consortium of several international institutions. The overall goal of WOCAT is to contribute to sustainable utilization of soil and water. WOCAT collects and analyzes information on soil and water conservation (SWC) technologies and approaches world-wide, and presents the collected information in computer databases and decision support systems, and in the form of handbooks, reports and maps readily accessible to SWC specialists and policy-makers world-wide. WOCAT has prepared a framework for the evaluation of soil and water conservation and has started data collection. The paper presents preliminary results with promising SWC technologies and approaches used in Eastern and Southern Africa. The first finding is that hardly any promising SWC activities could be found on common grazing lands. Analysis of the cropland shows some of the bio-physical and socioeconomic conditions under which certain SWC technologies and approaches are used, including land use types, climatic zones and land tenure, and looks at issues such as participation and costs. Furthermore, classification criteria for SWC technologies and approaches are discussed.

An innovative approach to impacting student academic achievement and attitudes: Pilot study of the HEADS UP Virtual Molecular Biology Lab

Objective. To evaluate the HEADS UP Virtual Molecular Biology Lab, a computer-based simulated laboratory designed to teach advanced high school biology students how to create a mouse model. ^ Design. A randomized clinical control design of forty-four students from two science magnet high schools in Mercedes, Texas was utilized to assess knowledge and skills of molecular laboratory procedures, attitudes towards science and computers as a learning tool, and usability of the program. ^ Measurements. Data was collected using five paper-and-pencil formatted questionnaires and an internal "lab notebook." ^ Results. The Virtual Lab was found to significantly increase student knowledge over time (p<0.005) and with each use (p<0.001) as well as positively increase attitudes towards computers (p<0.001) and skills (p<0.005). No significant differences were seen in science attitude scores.^ Conclusion. These results provide evidence that the HEADS UP Virtual Molecular Biology Lab is a potentially effective educational tool for high school molecular biology education.^

Advanced Protein Modeling Method: Benchmarking and Applications in Computer-Aided Drug Discovery

Development of homology modeling methods will remain an area of active research. These methods aim to develop and model increasingly accurate three-dimensional structures of yet uncrystallized therapeutically relevant proteins e.g. Class A G-Protein Coupled Receptors. Incorporating protein flexibility is one way to achieve this goal. Here, I will discuss the enhancement and validation of the ligand-steered modeling, originally developed by Dr. Claudio Cavasotto, via cross modeling of the newly crystallized GPCR structures. This method uses known ligands and known experimental information to optimize relevant protein binding sites by incorporating protein flexibility. The ligand-steered models were able to model, reasonably reproduce binding sites and the co-crystallized native ligand poses of the β2 adrenergic and Adenosine 2A receptors using a single template structure. They also performed better than the choice of template, and crude models in a small scale high-throughput docking experiments and compound selectivity studies. Next, the application of this method to develop high-quality homology models of Cannabinoid Receptor 2, an emerging non-psychotic pain management target, is discussed. These models were validated by their ability to rationalize structure activity relationship data of two, inverse agonist and agonist, series of compounds. The method was also applied to improve the virtual screening performance of the β2 adrenergic crystal structure by optimizing the binding site using β2 specific compounds. These results show the feasibility of optimizing only the pharmacologically relevant protein binding sites and applicability to structure-based drug design projects.

Servicio de referencia virtual por chat en bibliotecas universitarias

En este trabajo nos proponemos realizar un estudio sobre los servicios de referencia virtual por chat. Abordamos los distintos conceptos y su evolución a través del tiempo; analizamos los diferentes servicios ofrecidos por bibliotecas universitarias del mundo, y por último, planteamos una serie de recomendaciones para la implementación de un servicio de referencia virtual por chat en bibliotecas universitarias argentinas

Servicio de referencia virtual por chat en bibliotecas universitarias

En este trabajo nos proponemos realizar un estudio sobre los servicios de referencia virtual por chat. Abordamos los distintos conceptos y su evolución a través del tiempo; analizamos los diferentes servicios ofrecidos por bibliotecas universitarias del mundo, y por último, planteamos una serie de recomendaciones para la implementación de un servicio de referencia virtual por chat en bibliotecas universitarias argentinas

Servicio de referencia virtual por chat en bibliotecas universitarias

En este trabajo nos proponemos realizar un estudio sobre los servicios de referencia virtual por chat. Abordamos los distintos conceptos y su evolución a través del tiempo; analizamos los diferentes servicios ofrecidos por bibliotecas universitarias del mundo, y por último, planteamos una serie de recomendaciones para la implementación de un servicio de referencia virtual por chat en bibliotecas universitarias argentinas

Heckscher-Ohlin : evidence from virtual trade in value added

The fragmentation of production chains across borders is one of the most distinctive feature of the last 30 years of globalization. Nonetheless, our understanding of its implications for trade theory and policy is only in its infancy. We suggest that trade in value added should follow theories of comparative advantage more closely than gross trade, as value-added flows capture where factors of production, e.g. skilled and unskilled labor, are used along the global value chain. We find empirical evidence that Heckscher-Ohlin theory does predict manufacturing trade in value-added, and it does so better than for gross shipment flows. While countries exports across a broad range of sectors, they contribute more value-added in techniques using their abundant factor intensively.

The impact of a computer based adult literacy program on literacy and numeracy : evidence from India

With over 700 million illiterate adults in the world, many governments have implemented adult literacy programs across the world, although typically with low rates of success partly because the quality of teaching is low. One solution may lie in the standardization of teaching provided by computer-aided instruction. We present the first rigorous evidence of the effectiveness of a computer-based adult literacy program. A randomized control trial study of TARA Akshar Plus, an Indian adult literacy program, was implemented in the state of Uttar Pradesh in India. We find large, significant impacts of this computer-aided program on literacy and numeracy outcomes. We compare the improvement in learning to that of other traditional adult literacy programs and conclude that TARA Akshar Plus is effective in increasing literacy and numeracy for illiterate adult women.