The use of light- and electron microscopy for studies on the cell- and molecular biology of parasites and parasitic diseases

Lightmicroscopical (LM) and electron microscopi cal (EM) techniques, have had a major influence on the development and direction of cell biology, and particularly also on the investigation of complex host-parasite relationships. Earlier, microscopy has been rather descriptive, but new technical and scientific advances have changed the situation. Microscopy has now become analytical, quantitative and three-dimensional, with greater emphasis on analysis of live cells with fluorescent markers. The new or improved techniques that have become available include immunocytochemistry using immunogold labeling techniques or fluorescent probes, cryopreservation and cryosectioning, in situ hybridization, fluorescent reporters for subcellular localization, micro-analytical methods for elemental distribution, confocal laser scanning microscopy, scanning tunneling microscopy and live-imaging. Taken together, these tools are providing both researchers and students with a novel and multidimensional view of the intricate biological processes during parasite development in the host.

MULTIPLE DISEASES IN CARRIER PROBABILITY ESTIMATION: ACCOUNTING FOR SURVIVING ALL CANCERS OTHER THAN BREAST AND OVARY IN BRCAPRO

Mendelian models can predict who carries an inherited deleterious mutation of known disease genes based on family history. For example, the BRCAPRO model is commonly used to identify families who carry mutations of BRCA1 and BRCA2, based on familial breast and ovarian cancers. These models incorporate the age of diagnosis of diseases in relatives and current age or age of death. We develop a rigorous foundation for handling multiple diseases with censoring. We prove that any disease unrelated to mutations can be excluded from the model, unless it is sufficiently common and dependent on a mutation-related disease time. Furthermore, if a family member has a disease with higher probability density among mutation carriers, but the model does not account for it, then the carrier probability is deflated. However, even if a family only has diseases the model accounts for, if the model excludes a mutation-related disease, then the carrier probability will be inflated. In light of these results, we extend BRCAPRO to account for surviving all non-breast/ovary cancers as a single outcome. The extension also enables BRCAPRO to extract more useful information from male relatives. Using 1500 familes from the Cancer Genetics Network, accounting for surviving other cancers improves BRCAPRO’s concordance index from 0.758 to 0.762 (p = 0.046), improves its positive predictive value from 35% to 39% (p < 10−6) without impacting its negative predictive value, and improves its overall calibration, although calibration slightly worsens for those with carrier probability < 10%. Copyright c 2000 John Wiley & Sons, Ltd.

Evidence and structural mechanism for late lung alveolarization

According to the current view, the formation of new alveolar septa from preexisting ones ceases due to the reduction of a double- to a single-layered capillaries network inside the alveolar septa (microvasculature maturation postnatal days 14-21 in rats). We challenged this view by measuring stereologically the appearance of new alveolar septa and by studying the alveolar capillary network in three-dimensional (3-D) visualizations obtained by high-resolution synchrotron radiation X-ray tomographic microscopy. We observed that new septa are formed at least until young adulthood (rats, days 4-60) and that roughly half of the new septa are lifted off of mature septa containing single-layered capillary networks. At the basis of newly forming septa, we detected a local duplication of the capillary network. We conclude that new alveoli may be formed in principle at any time and at any location inside the lung parenchyma and that lung development continues into young adulthood. We define two phases during developmental alveolarization. Phase one (days 4-21), lifting off of new septa from immature preexisting septa, and phase two (day 14 through young adulthood), formation of septa from mature preexisting septa. Clinically, our results ask for precautions using drugs influencing structural lung development during both phases of alveolarization.

The clinical and structural long-term results of open repair of massive tears of the rotator cuff

BACKGROUND: At a mean follow-up of 3.1 years, twenty-seven consecutive repairs of massive rotator cuff tears yielded good and excellent clinical results despite a retear rate of 37%. Patients with a retear had improvement over the preoperative state, but those with a structurally intact repair had a substantially better result. The purpose of this study was to reassess the same patients to determine the long-term functional and structural results. METHODS: At a mean follow-up interval of 9.9 years, twenty-three of the twenty-seven patients returned for a review and were examined clinically, radiographically, and with magnetic resonance imaging with use of a methodology identical to that used at 3.1 years. RESULTS: Twenty-two of the twenty-three patients remained very satisfied or satisfied with the result. The mean subjective shoulder value was 82% (compared with 80% at 3.1 years). The mean relative Constant score was 85% (compared with 83% at 3.1 years). The retear rate was 57% at 9.9 years (compared with 37% at 3.1 years; p = 0.168). Patients with an intact repair had a better result than those with a failed reconstruction with respect to the mean absolute Constant score (81 compared with 64 points, respectively; p = 0.015), mean relative Constant score (95% and 77%; p = 0.002), and mean strength of abduction (5.5 and 2.6 kg; p = 0.007). The mean retear size had increased from 882 to 1164 mm(2) (p = 0.016). Supraspinatus and infraspinatus muscle fatty infiltration had increased (p = 0.004 and 0.008, respectively). Muscles with torn tendons preoperatively showed more fatty infiltration than muscles with intact tendons preoperatively, regardless of repair integrity. Shoulders with a retear had a significantly higher mean acromion index than those without retear (0.75 and 0.65, respectively; p = 0.004). CONCLUSIONS: Open repair of massive rotator cuff tears yielded clinically durable, excellent results with high patient satisfaction at a mean of almost ten years postoperatively. Conversely, fatty muscle infiltration of the supraspinatus and infraspinatus progressed, and the retear size increased over time. The preoperative integrity of the tendon appeared to be protective against muscle deterioration. A wide lateral extension of the acromion was identified as a previously unknown risk factor for retearing.

MODEL UPDATING AND STRUCTURAL HEALTH MONITORING OF HORIZONTAL AXIS WIND TURBINES VIA ADVANCED SPINNING FINITE ELEMENTS AND STOCHASTIC SUBSPACE IDENTIFICATION METHODS

Wind energy has been one of the most growing sectors of the nation’s renewable energy portfolio for the past decade, and the same tendency is being projected for the upcoming years given the aggressive governmental policies for the reduction of fossil fuel dependency. Great technological expectation and outstanding commercial penetration has shown the so called Horizontal Axis Wind Turbines (HAWT) technologies. Given its great acceptance, size evolution of wind turbines over time has increased exponentially. However, safety and economical concerns have emerged as a result of the newly design tendencies for massive scale wind turbine structures presenting high slenderness ratios and complex shapes, typically located in remote areas (e.g. offshore wind farms). In this regard, safety operation requires not only having first-hand information regarding actual structural dynamic conditions under aerodynamic action, but also a deep understanding of the environmental factors in which these multibody rotating structures operate. Given the cyclo-stochastic patterns of the wind loading exerting pressure on a HAWT, a probabilistic framework is appropriate to characterize the risk of failure in terms of resistance and serviceability conditions, at any given time. Furthermore, sources of uncertainty such as material imperfections, buffeting and flutter, aeroelastic damping, gyroscopic effects, turbulence, among others, have pleaded for the use of a more sophisticated mathematical framework that could properly handle all these sources of indetermination. The attainable modeling complexity that arises as a result of these characterizations demands a data-driven experimental validation methodology to calibrate and corroborate the model. For this aim, System Identification (SI) techniques offer a spectrum of well-established numerical methods appropriated for stationary, deterministic, and data-driven numerical schemes, capable of predicting actual dynamic states (eigenrealizations) of traditional time-invariant dynamic systems. As a consequence, it is proposed a modified data-driven SI metric based on the so called Subspace Realization Theory, now adapted for stochastic non-stationary and timevarying systems, as is the case of HAWT’s complex aerodynamics. Simultaneously, this investigation explores the characterization of the turbine loading and response envelopes for critical failure modes of the structural components the wind turbine is made of. In the long run, both aerodynamic framework (theoretical model) and system identification (experimental model) will be merged in a numerical engine formulated as a search algorithm for model updating, also known as Adaptive Simulated Annealing (ASA) process. This iterative engine is based on a set of function minimizations computed by a metric called Modal Assurance Criterion (MAC). In summary, the Thesis is composed of four major parts: (1) development of an analytical aerodynamic framework that predicts interacted wind-structure stochastic loads on wind turbine components; (2) development of a novel tapered-swept-corved Spinning Finite Element (SFE) that includes dampedgyroscopic effects and axial-flexural-torsional coupling; (3) a novel data-driven structural health monitoring (SHM) algorithm via stochastic subspace identification methods; and (4) a numerical search (optimization) engine based on ASA and MAC capable of updating the SFE aerodynamic model.