The Geography of Logistics Firm Location: The Role of Accessibility

The organization of modern economies is built upon an efficient transport system and an increasing role is played by the logistics sector in overcoming the constraints of time and distance in modern supply chains. While a large body of literature is dedicated to the spatial distribution of firms and firm location choice in general, surprisingly little is still known about the location patterns of logistics firms, and more specifically about the role of accessibility in their location decisions. We use geo-referenced firm level data along with detailed information on transport infrastructure in order to investigate the geography of logistics firms in Spain. We place specific attention to the relationship between logistics firm location, accessibility, and urban structure. Our results show that these firms are located closer to highways and other transport infrastructure compared to other sectors and that the logistics sector is highly urbanized. Yet, they are also locating increasingly in suburban locations and to some extent in extra-urban locations with good accessibility while central cities of urban areas have experienced a declining share of logistics firms

Imaging Mass Spectrometry Visualizes Ceramides and the Pathogenesis of Dorfman-Chanarin Syndrome Due to Ceramide Metabolic Abnormality in the Skin

Imaging mass spectrometry (IMS) is a useful cutting edge technology used to investigate the distribution of biomolecules such as drugs and metabolites, as well as to identify molecular species in tissues and cells without labeling. To protect against excess water loss that is essential for survival in a terrestrial environment, mammalian skin possesses a competent permeability barrier in the stratum corneum (SC), the outermost layer of the epidermis. The key lipids constituting this barrier in the SC are the ceramides (Cers) comprising of a heterogeneous molecular species. Alterations in Cer composition have been reported in several skin diseases that display abnormalities in the epidermal permeability barrier function. Not only the amounts of different Cers, but also their localizations are critical for the barrier function. We have employed our new imaging system, capable of high-lateral-resolution IMS with an atmospheric-pressure ionization source, to directly visualize the distribution of Cers. Moreover, we show an ichthyotic disease pathogenesis due to abnormal Cer metabolism in Dorfman–Chanarin syndrome, a neutral lipid storage disorder with ichthyosis in human skin, demonstrating that IMS is a novel diagnostic approach for assessing lipid abnormalities in clinical setting, as well as for investigating physiological roles of lipids in cells/tissues