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STUDY QUESTION Has PGD-HLA been successful relative to diagnostic and clinical efficacy? SUMMARY ANSWER The diagnostic efficacy of PGD-HLA protocols was found lower in this study in comparison to published PGD-HLA protocols and to that reported for general PGD by ESHRE (78.5 vs 94.1% and vs 92.6%, respectively), while the clinical efficacy has proven very difficult to assess due to inadequate follow-up of both the ART/PGD and HSCT procedure outcomes. WHAT IS KNOWN ALREADY The first clinical cases for PGD-HLA were reported in 2001. It is now a well-established procedure, with an increasing number of cycles performed every year. However, PGD-HLA is still offered by relatively few PGD centres, the currently available data is fragmented and most reports on PGD-HLA applications are limited in number and scope. Published systematic details on methodology, diagnostic results, overall ART success and haematopoietic stem cell transplantation (HSCT) outcomes are limited, precluding an evaluation of the true clinical utility of PGD-HLA cycles. STUDY DESIGN, SIZE, DURATION This retrospective multi-centre cohort study aimed to investigate the diagnostic and clinical efficacy of the PGD-HLA procedure and the aspects of PGD-HLA cycles influencing positive outcomes: birth of genetically suitable donor-baby (or babies) and HSCT. In April 2014, 32 PGD centres (Consortium members and non-members) with published/known PGD-HLA activity were invited to participate. Between February and September 2015, 14 centres submitted their data, through a custom-designed secure database, with unique login access for each centre. Data parameters covered all aspects of PGD-HLA cycles (ART, embryology and genetic diagnosis), donor-babies born and HSCT. PARTICIPANTS/MATERIALS, SETTING, METHODS From 716 cycles submitted by 14 centres (performed between August 2001 and September 2015), the quality evaluation excluded 12 cycles, leaving 704, from 364 couples. The online database, based on REDCap, a free, s

A new model for equilibria at the interface of a sparingly soluble crystal is reviewed. It provides that several kinds of equilibria are present and each type is characterized by (i) a set of species that are transported across the phase boundary, (ii) a set · of chemical reactions which describe this transport process, and (iii) a set of thermodynamic expressions which define equilibrium. Three types are envisaged: 1. Stoichiometric equilibrium provides the thermodynamic communication between the lattice and the bulk solution, occurs at a kink site, preserves the composition of the solid phase, defines a solubility product, leads to an isotherm in the phase diagram, and is unaffected by Galvani potentials. The equilibrium is defined by a single equation. 2. Gibbsian equilibrium in which the chemical potential of each component is stated to be equal across the phase boundary, but does not define an actual chemical process. There is one such equation for each component in the system. 3. Electrochemical equilibrium provides thermodynamic communication between ions in the bulk phase and those in the outer layer of the crystal, is nonstoichiometric, is profoundly affected by Galvani potentials, does not lead to a solubility product constant nor to an isotherm, and requires one more equilibrium condition than there are components in the system. Equilibrium between the lattice and the surface is limited to reactions via the aqueous phase, one of which is stoichiometric and the other nonstoichiometric. This model provides a clarity of description of interfacial events heretofore unattainable.

Dissolution and precipitation reactions that occur in biological systems and in non-stirred in vitro systems generally are diffusion-controlled. Subsurface demineralization of tooth enamel in dental caries, which has been the subject of considerable interest, is an example of such processes. In the caries process ions from solubilized tooth mineral, i. e., Ca, P04, and OH, need to be transported from the lesion below the tooth surf'ace to the plaque and eventually into the saliva.

A new model for equilibria at the interface of a sparingly soluble crystal is reviewed. It provides that several kinds of equilibria are present and each type is characterized by (i) a set of species that are transported across the phase boundary, (ii) a set · of chemical reactions which describe this transport process, and (iii) a set of thermodynamic expressions which define equilibrium. Three types are envisaged: 1. Stoichiometric equilibrium provides the thermodynamic communication between the lattice and the bulk solution, occurs at a kink site, preserves the composition of the solid phase, defines a solubility product, leads to an isotherm in the phase diagram, and is unaffected by Galvani potentials. The equilibrium is defined by a single equation. 2. Gibbsian equilibrium in which the chemical potential of each component is stated to be equal across the phase boundary, but does not define an actual chemical process. There is one such equation for each component in the system. 3. Electrochemical equilibrium provides thermodynamic communication between ions in the bulk phase and those in the outer layer of the crystal, is nonstoichiometric, is profoundly affected by Galvani potentials, does not lead to a solubility product constant nor to an isotherm, and requires one more equilibrium condition than there are components in the system. Equilibrium between the lattice and the surface is limited to reactions via the aqueous phase, one of which is stoichiometric and the other nonstoichiometric. This model provides a clarity of description of interfacial events heretofore unattainable.

Dissolution and precipitation reactions that occur in biological systems and in non-stirred in vitro systems generally are diffusion-controlled. Subsurface demineralization of tooth enamel in dental caries, which has been the subject of considerable interest, is an example of such processes. In the caries process ions from solubilized tooth mineral, i. e., Ca, P04, and OH, need to be transported from the lesion below the tooth surf'ace to the plaque and eventually into the saliva.

This document contains three letters with summaries of Army Air Forces China Theater activities (China Air Service Command, Air Transport Command) written by Lt. General George E. Stratemeyer, Lt. General A. C. Wedemeyer, and Director, Commission on Aeronautical Affairs, C. J. Chow.