Waiting list mortality and the potential of donation after circulatory death heart transplantations in the Netherlands

BACKGROUND: With more patients qualifying for heart transplantation (HT) and fewer hearts being transplanted, it is vital to look for other options. To date, only organs from brain-dead donors have been used for HT in the Netherlands. We investigated waiting list mortality in all Dutch HT centres and the potential of donation after circulatory death (DCD) HT in the Netherlands. METHODS: Two different cohorts were evaluated. One cohort was defined as patients who were newly listed or were already on the waiting list for HT between January 2013 and December 2017. Follow-up continued until September 2018 and waiting list mortality was calculated. A second cohort of all DCD donors in the Netherlands (lung, liver, kidney and pancreas) between January 2013 and December 2017 was used to calculate the potential of DCD HT. RESULTS: Out of 395 patients on the waiting list for HT, 196 (50%) received transplants after a median waiting time of 2.6 years. In total, 15% died while on the waiting list before a suitable donor heart became available. We identified 1006 DCD donors. After applying exclusion criteria and an age limit of 50 years, 122 potential heart donors remained. This number increased to 220 when the age limit was extended to 57 years. CONCLUSION: Waiting list mortality in the Netherlands is high. HT using organs from DCD donors has great potential in the Netherlands and could lead to a reduction in waiting list mortality. Cardiac screening will eventually determine the true potential

PQS (Polar Qualification System) the new data reduction and product qualification method

The near infrared spectra are useful information sources relating to quality (e.g. composition) of a material examined. To obtain and interpret useful information requires in most cases the application of sophisticated methods of mathematical statistics. A method different from those mentioned above, implementing a large scale data reduction based on geometrical consideration is the PQS. According to this method, the quality of a material can be characterised by the centre of its spectrum represented in a polar co-ordinate system. In many cases it is enough to know whether the investigated product deviates in a certain degree from a given “standard product” or not. This can be decided by determining special “distances” between the two (investigated and standard) products using their near infrared spectra. Besides the successfully used Euclidean and Mahalanobis distances a new one, the “polar distance” was introduced giving the distance between the two centres (quality points) of the spectra of the two products examined. A method was elaborated to select the optimal wavelength range giving the maximum normalised distance between the two quality points of the investigated products. The so called “wavelength range optimisation” can not be used to work with non spectral data sets. While in case of NIR spectra the sequence of the data are determined by nature, in several cases the order of the data can be freely varied and the goal is the determination of the optimal data sequence. By introducing the “sequence optimisation” PQS could be generalised and used from the field of near infrared spectroscopy to solve any kind of multivariate tasks. The advantage of the PQS optimisation method is its simplicity. Since PQS was developed to extract the needed information from NIR spectra, the basic principles of the technique are introduced with the help of near infrared spectra of some milk powder samples of different fat content. The sequence optimisation is demonstrated with the sensor signal responses of an electronic nose (chemosensor array) instrument measuring different steam distilled volatile oil samples

Turning Paris into reality at the University of California

The Paris Agreement highlights the need for local climate leadership. The University Of California's approach to deep decarbonization offers lessons in efficiency, alternative fuels and electrification. Bending the emissions curve globally requires efforts that blend academic insights with practical solutions