A disease approach using linkage analysis: Still in geneticists’ quiver

Linkage analysis, based on Mendel’s law of independent assortment, has contributed the most to the late advance of human genetics. In this article we present a way of approaching a disease by the use of this technique. The first step is to use a set of families where the disease segregates. Large pedigrees are preferable. Then all the members of these families are analyzed using an initial set of markers to detect an area of high interest. A common approach is to re-examine the same families with markers spaced closer to the chromosome in order to narrow the relevant area. Later, taking into account the existing knowledge, the hypothesis of the candidate gene is made and we try to prove it. The final study, as well as the final result are both influenced by the kind of families that are chosen, the suitability of the markers and the criteria used for proving a candidate gene hypothesis. Mendelian diseases were the first to be studied, but the real challenge for geneticists is detecting loci influencing complex diseases and linkage analysis remains still an effective approach

The role of peptides in bone healing and regeneration: A systematic review

Background: Bone tissue engineering and the research surrounding peptides has expanded significantly over the last few decades. Several peptides have been shown to support and stimulate the bone healing response and have been proposed as therapeutic vehicles for clinical use. The aim of this comprehensive review is to present the clinical and experimental studies analysing the potential role of peptides for bone healing and bone regeneration. Methods: A systematic review according to PRISMA guidelines was conducted. Articles presenting peptides capable of exerting an upregulatory effect on osteoprogenitor cells and bone healing were included in the study. Results: Based on the available literature, a significant amount of experimental in vitro and in vivo evidence exists. Several peptides were found to upregulate the bone healing response in experimental models and could act as potential candidates for future clinical applications. However, from the available peptides that reached the level of clinical trials, the presented results are limited. Conclusion: Further research is desirable to shed more light into the processes governing the osteoprogenitor cellular responses. With further advances in the field of biomimetic materials and scaffolds, new treatment modalities for bone repair will emerge

Computer Assisted Mass Appraisals for residential properties in Greece

220 σ.Η αγορά των ακινήτων στην Ελλάδα διέρχεται την έκτη συνεχή χρονιά ύφεσης, η οικοδομική δραστηριότητα έχει σχεδόν μηδενιστεί και ένας από τους άλλοτε κύριους πυλώνες της ελληνικής οικονομίας συνεισφέρει πλέον ελάχιστα στο Α.Ε.Π. της χώρας. Η κατάσταση αυτή έχει συμπαρασύρει αντίστοιχα και τις τιμές των ακινήτων, ενώ πρόσφατη έρευνα κατατάσσει την Ελλάδα στην 55η και τελευταία θέση από τις χώρες που μελετώνται, με μείωση στις τιμές των κατοικιών από το 2009 σε ποσοστό 31%. Αντίθετα όμως, η οικονομική συγκυρία καθώς και οι υποχρεώσεις που έχουν αναληφθεί στο πλαίσιο των δεσμεύσεων με τους εξωτερικούς δανειστές της χώρας επιβάλλουν σκληρά μέτρα φορολόγησης σε φυσικά και νομικά πρόσωπα. Μία από τις πηγές φορολογικών εσόδων σε τέτοιες περιπτώσεις αποτελεί πάντα η ακίνητη περιουσία, της οποίας όμως η τρέχουσα υπερφορολόγηση με πλέον των 40 φόρων, τελών και αμοιβών, έχει οδηγήσει τους υπόχρεους σε αδιέξοδο. Το πρόβλημα διογκώνεται, αν συνυπολογίσουμε τις υποχρεώσεις που έχουν δημιουργηθεί λόγω της έξαρσης χορήγησης στεγαστικών δανείων κατά τα προηγούμενα χρόνια, οι οποίες πλέον είναι εξαιρετικά δύσκολο να καλυφθούν με το καταγεγραμμένο ποσοστό ανεργίας να φτάνει το 27,9% τον Ιούνιο του 2013 (58,8% για τους νέους έως 24 ετών), χωρίς να καταγράφονται σε αυτό οι ελεύθεροι επαγγελματίες χωρίς αντικείμενο και οι έχοντες εργασία χωρίς να αμείβονται. Είναι σαφές λοιπόν, ότι έχει φθάσει ο χρόνος για έναν ορθολογικότερο και πιο δίκαιο τρόπο φορολόγησης της ακίνητης περιουσίας, που θα περιορίσει τις ανισότητες και τις αδικίες, που θα βασίζεται πραγματικά στην αγορά και που θα είναι σαφής και τεκμηριωμένος. Το Σύστημα Αντικειμενικού Προσδιορισμού Αξιών Ακινήτων, ήρθε το 1985 να καλύψει φαινόμενα αδιαφάνειας στον μέχρι τότε τρόπο φορολόγησης των ακινήτων, ενώ σε συνδυασμό με το περιουσιολόγιο επιχειρούν την πλήρη καταγραφή και φορολόγηση της ακίνητης περιουσίας στην Ελλάδα. Από τη χρήση του όμως διαπιστώνεται πως είναι ένα σύστημα μη ευέλικτο και προσαρμόσιμο τόσο στις εξελίξεις όσο και στις ιδιαιτερότητες & την τρέχουσα πραγματικότητα της αγοράς, εξαρτώμενο άμεσα από αποφάσεις με πολιτικό κόστος και εφαρμογές πολιτικής γης, το οποίο όμως πλέον μάλλον δημιουργεί περισσότερες στρεβλώσεις από όσες θεραπεύει. Ακόμα μία στρέβλωση στην ελληνική αγορά ακινήτων, λόγω της υψηλής φορολόγησης, είναι ότι δεν είναι γνωστές και δεν καταγράφονται πουθενά οι τιμές πώλησης των ακινήτων, οι οποίες παραμένουν γνωστές μόνο στα συμβαλλόμενα μέρη, στερώντας πολύτιμη πληροφορία για την παρακολούθηση της αγοράς, αλλά και φορολογικά έσοδα μιας και σε πολλές περιπτώσεις ακόμα και σήμερα, οι φορολογητέες αξίες υπολείπονται κατά πολύ των εμπορικών. Τέλος, το Εθνικό Κτηματολόγιο δεν έχει ολοκληρωθεί ώστε να υπάρχει μία πλήρης, αξιόπιστη και αποδεικτική καταγραφή των ιδιοκτησιακών δικαιωμάτων στη χώρα. Προχωρώντας όμως έστω και με ρυθμούς βραδύτερους από αυτούς που θα απαιτούσαν οι συνθήκες, παραμένει ένα πολύ ισχυρό αναπτυξιακό εργαλείο το οποίο βρίσκεται σε ισχύ σε αρκετές περιοχές της χώρας και πάνω στο οποίο μπορεί και πρέπει να βασιστεί το σύστημα φορολόγησης των ακινήτων στην Ελλάδα, δίνοντας δυνατότητες ακριβούς και δίκαιου καταμερισμού του φορολογικού φορτίου. Τα μοναδικά ασφαλή δεδομένα εμπορικών αξιών ακινήτων για τον ελληνικό χώρο μπορούν να αναζητηθούν στις εκθέσεις εκτίμησης που συντάσσουν επαγγελματίες εκτιμητές. Τα στοιχεία αυτά υποβάλλονται από το 2009 και καταγράφονται από την Τράπεζα της Ελλάδος, ως εργαλείο ανάλυσης της αγοράς και παραγωγής δεικτών. Ταυτόχρονα φαίνεται πως υπάρχει μία τάση για ελεύθερη και δωρεάν διάθεση γεωγραφικών και άλλων δεδομένων όχι μόνο στο στενό πλαίσιο του Δημοσίου πλέον, αλλά και προς κάθε ενδιαφερόμενο. Σε περιπτώσεις απαίτησης της γνώσης της αξίας των ακινήτων σε μικρή κλίμακα, όπως για παράδειγμα για φορολογικούς σκοπούς, έχουν εφαρμογή οι μέθοδοι των Μαζικών Εκτιμήσεων, η λογική των οποίων βασίζεται στην όσο το δυνατόν καλύτερη προσέγγιση της αξίας ομάδας ακινήτων, με μονάδα αναφοράς το κάθε ακίνητο, αλλά χωρίς τη βούληση και τη δυνατότητα να υποκαταστήσουν τις επί μέρους εκτιμήσεις και να συνυπολογίσουν όλους τους παράγοντες που λαμβάνονται υπ’ όψιν στις αυτοτελείς εκτιμήσεις. Τα Συστήματα Μαζικών Εκτιμήσεων εφαρμόζονται με ικανοποιητική επιτυχία εδώ και αρκετά χρόνια κυρίως σε πολιτείες των Η.Π.Α., αλλά πλέον και σε αρκετές ευρωπαϊκές χώρες. Η εφαρμογή τους γίνεται περιοδικά για επανεκτίμηση όλων των ακινήτων που ανήκουν συνήθως σε κάποια διοικητική περιφέρεια και βασίζονται ως επί το πλείστον σε πραγματικά στοιχεία πωλήσεων. Η εξέλιξη των συστημάτων αυτών περιλαμβάνει την αυτοματοποίησή τους μέσω υπολογιστικών συστημάτων (Computer Assisted Mass Appraisals), την ολοκλήρωσή τους με γεωγραφικά συστήματα πληροφοριών και τη χρήση τεχνητής νοημοσύνης, νευρωνικών δικτύων, συστημάτων ασαφούς θεωρίας, στοχαστικών μοντέλων και θεωρίας προσεγγιστικών συνόλων. Ειδικά για τα ολοκληρωμένα συστήματα CAMA, αν και μελετώνται εδώ και αρκετά χρόνια, βρίσκονται ακόμα σε στάδιο έρευνας κι εξέλιξης. Για την υλοποίησή τους συνήθως απαιτούνται αρκετά χρόνια μελέτης κι εργασιών και διεπιστημονική αντιμετώπιση από πλήθος επαγγελματιών, ενώ δομούνται κατά περίπτωση και διαφέρουν ακόμα και ανάμεσα σε διοικητικές μονάδες της ίδιας χώρας. Για τον ελληνικό χώρο μία τέτοια εξέλιξη μελετάται ερευνητικά από τις αρχές της δεκαετίας του 2000, αν και η αντιμετώπιση θεμάτων Μαζικών Εκτιμήσεων έχει ξεκινήσει με τη Διδακτορική Διατριβή του Ομότιμου Καθηγητή κ. Παναγιώτη Ζεντέλη από το 1988. Αυτοματοποίηση όμως των διαδικασιών και πρακτική εφαρμογή τους ήταν αδύνατο να υπάρξει χωρίς γεωγραφικά, οικονομικά και τεχνικά δεδομένα, γεγονότα που οδηγούσαν την έρευνα σε αδιέξοδο. Με τις τελευταίες εξελίξεις στο χώρο της καταγραφής και ελεύθερης διανομής δεδομένων (ΤτΕ, ΟΚΧΕ, Κτηματολόγιο ΑΕ, ΕΛ.ΣΤΑΤ κλπ), αλλά και με τις αυξανόμενες δυνατότητες των υπολογιστικών συστημάτων, ήταν πλέον δυνατή η προσέγγιση του θέματος, έστω και με πολλά συγκριτικά μειονεκτήματα ως προς τα πρωτογενή στοιχεία σε σχέση με τη διεθνή βιβλιογραφία και πρακτική. Το σύστημα με την επωνυμία CAMA.gr σχεδιάστηκε για τον ελληνικό χώρο και αναπτύχθηκε βάσει πραγματικών δεδομένων, αφορά σε ακίνητα δύο Δήμων της Αττικής με διαφορετικά χαρακτηριστικά μεταξύ τους και λειτουργεί δυναμικά μέσα από την Oracle Spatial, μπορεί όμως να διαχειριστεί από οποιαδήποτε πλατφόρμα γεωγραφικών συστημάτων πληροφοριών. Το σύστημα ελέγχθηκε κατά τη δημιουργία του, τόσο για τις διαδικασίες όσο και για τα αποτελέσματα με επιτυχία και θα μπορούσε με τις κατάλληλες τροποποιήσεις να λειτουργήσει από την κεντρική διοίκηση για δημοσιονομικούς σκοπούς. Μελλοντικές επεκτάσεις του συστήματος, οι οποίες ήδη βρίσκονται υπό μελέτη, αφορούν στη δυνατότητα χωρικής αναπαράστασης και άλλων σημαντικών παραγόντων (για παράδειγμα της θέας σε τρισδιάστατο περιβάλλον) ώστε να μπορέσει να διαπιστωθεί η επιρροή τους στην αξία των ακινήτων, στην αναλυτικότερη στατιστική ανάλυση (για παράδειγμα σε επίπεδο γειτονιάς, αλλά και με περισσότερα μοντέλα παλινδρόμησης), στη μελέτη και άλλων κατηγοριών ακινήτων (για παράδειγμα επαγγελματικής χρήσης), αλλά και στην πλήρη αυτοματοποίησή του με την συμπλήρωση του κώδικα προγραμματισμού που το υποστηρίζει. Για το λόγο αυτό αναπτύχθηκε το CAMA.gr, το οποίο δεν προσομοιάζει κάποιου υφιστάμενου διεθνώς, είναι προσαρμοσμένο στις ιδιαιτερότητες του ελληνικού χώρου και πέρα από την ερευνητική του διάσταση μπορεί να εφαρμοστεί άμεσα σε επίπεδο χώρας, ώστε να βοηθήσει αποτελεσματικά τη δημοσιονομική πολιτική της χώρας.Global economy is going through difficult and challenging times. Europe and especially the countries of the south are facing enormous fiscal difficulties, rising unemployment, dropping wages and cut-backs on social expenses. Greece is entering its sixth year of depression and the consequences are more than obvious in every aspect of social, professional and economical life. Real Estate used to be one of the capstones of the Hellenic economy, but since 2007 its contribution to the GDP has dropped dramatically. Instead of implementing solutions towards the recovery of the Real Estate market, Hellenic State is increasing the levy by enforcing new taxes to the transaction, improvement, use and even possession of Real Estate property, resulting to the simultaneous existence of more than 40 different individual property taxes, leading to the “criminalization” of property owning. Except from the taxes on transactions (purchases, inheritances, donations) and the periodical taxation (on total properties’ value), extra taxes have been added (tax on all electrified properties etc) as well as additional dues (for “legalising” improper constructions, issuing energy-efficiency certificates, issuing certificates for irregularities-free properties etc) In Greece, Property Sales Data is not public. In fact, only very few specific people get to know the price of a transaction which is a secret between the seller & the buyer. If a Real Estate Agent is involved he probably knows too, while if a Bank is financing the loan, they just know the valuation and the requested loan. Given that there is no operational Computer Assisted Mass Appraisal, taxation until 1985 had been subject to negotiation between the tax authorities and the owners. Since 1985 the taxable values on which taxes are imposed are called “objective values” and are calculated according to the “Real Estate Values Objective Calculation System”, a Mass Taxation System, assigned with base (zone) values within Municipalities, as well as few basic quality factors augmenting or reducing the initial values. It is a generic, non-flexible tool, periodically updated (mostly the base values of each zone) by a committee, producing taxable values irrelevant to the market values, and consequently being used as a land-policy tool. The system was designed to be updated every 2 years, but since it invokes great political cost, it usually takes much longer to update, with the last update dating back to March 2007. Except from being impossible for the system to simulate the function of the market, each update disturbs and intervenes to the market’s equilibrium, since before the update prices go sky-high and just after the market instantly falls into comma. The Basis for residential appraisals is usually the Market Value and for certain detached residences the Depreciated Replacement Cost. Since the Market Values are not known or registered the Basis for Real Estate taxation, professional fees, expropriations etc is the “objective” value. Tax on contracts (transactions) is imposed on the maximum of the “objective” & the transaction value and surely not on less than the “objective” value. It is obvious that everybody or at least Individuals (not Companies) state that the transaction price was somewhere near the “objective”, so valuable data is being lost. The Scope of Real Estate Appraisals in Greece usually involves Bank Loans (mortgages), Buying or selling a property, Insuring a property (improvements value), New constructions / repairs / improvements, Consumer loans with property insurance, Leasing / Sale & Lease Back, Revaluations (change of loan terms, change of property characteristics, periodical according to legislation), Auctions, and Mortgages to cover loans not being paid-back. Appraisals in Greece, are mostly carried-out by the Body of Sworn-In Valuers who are the Official State Valuers, Most Monetary Financial Institutions either in-house or outsourced depending on the Real Estate section of the Bank, Valuation Companies and International Real Estate Houses. Independent Valuers, certified (RICS, REV-TEGoVA) or not, are mostly Engineers (Surveyors, Civil Engineers & Architects), many Economists and few M.Sc. in valuation (since no B.Sc. available in Greek Institutions). No legal framework on Valuation and Valuers exist, “Real Estate Valuer” specialty is not a recognised profession by the State, no Legal Fees and specific income confrontation from Taxation Authority apply, there is no specific Code of Ethics, no Valuation Chamber and no other Chambers can include a Valuer. All the above are partially cured only through certifications Valuers get and by restrictions within independent professions (i.e.: engineering code of ethics) Until recently “Market values” data could only be found in classified ads and via R.E. Agents, Properties legal & technical data only locally in municipalities, being rare & inconsistent and Basic Statistical data only in the Hellenic Statistical Authority’s tables. Today major steps have been taken as the 2610/2008 Bank of Greece Governor's Act, about compulsory monthly submission of selected data from all valuations carried out by MFIs (Monetary Financial Institutions) in Greece, the 3979/2011 Law, about free access of all Public Sector Institutions to all Public Sector ICT (Information & Communications Technology) data and about the operation of a free-access geodata portal and other Independent acts of the Hellenic Mapping & Cadastral Organization, Cadastral Institution, various Municipalities and many other Institutions for the production and disposition of geographic data. Despite -and because of- the crisis and the inactive Hellenic Real Estate Market, Real Estate management tends to mature and become more rational. So, the need is emerging for a more sophisticated, scientific, automated and intervention-secure system for the mass valuation of real estate values for fiscal purposes. Significant difficulties existing until now -lack of public comparable data, partial existence of Cadastral data and multiple laws- finally seem to be overrunable. The Model proposed is mainly developed for fiscal (taxation) purposes, aiming to a more rational real estate taxation system. It is designed for central (government) operation with various levels of access, security and functionality and the ability to serve as a reference base for market values and a valuation tool for big real estate portfolios. It could also be used as a Development Tool for national-state expropriations, land-exchange, large-scale development projects etc, an Analysis Tool using statistics, producing indices etc and a Land Policy tool, connected to social, economic & geographical criteria. The Basis of the Appraisal System is the Market Value (since input data comprises of assessed Market Values) and the Fair Value (since final assessed properties are not examined in detail). As for the Institutional Framework, the most suitable organization for hosting the project seems to be Ktimatologio S.A. the Carrier of the Hellenic Cadastre. The System is currently developed for residential properties, especially since there is no official data for commercial properties. Types of data collected consist of Spatial factors as the walking distance from significant POIs, metro stations etc, Area characteristics as the area’s land-use and the building coefficients etc and Property characteristics as floor, age, orientation etc. Two different Municipalities have been selected as the study area of the project. Municipality of Chalandri is situated among the Northern Suburbs of the Region of Attica, it is a rather nice living area and was mainly selected due to its complexity in terms of land-use, being residential and commercial as well, residing among some of the most important avenues of Athens and having great access and public transportation coverage. Voula on the other hand is an expensive coastal residential area of the Southern Suburbs, is considered a privileged area to live at and finally there is no operational cadastral office. Data collection was a very important and time consuming procedure. The Mass-Appraisal system proposed, aims to use all available official data, in order to produce fair and indisputable property values for taxation purposes. The main contributors were: - The Bank of Greece, providing original data from the submitted valuations by the MFIs in xls format with all valuations submitted since 01.01.2009, containing certain fields of about 1650 valuations (1150: Chalandri, 500: Voula). The property address was considered sensitive personal data and was not provided at first, finally though it was granted, but the address number was altered. There were several problems in data consistency as different correct writings of the same name, orthographic errors, editing mistakes etc. Existing data was harmonized, and future data was modeled so data entry will be made easy and error-free through proper drop-down menus and additional fields were added for each of the 4 maximum possible parcels “faces” of the property. Also, prices indices were used, short/long term, by age, by geographic area, historic series, trends & prospects, transactions. The scattering of the data was very satisfactory, so it seems to uniformly cover the two areas. - The Hellenic Cadastral Institution (Ktimatologio S.A.) was the second major contributor providing GIS data (City Boundaries, Cadastral Parcels, Buildings, Street Names), Descriptive data (PST, ORT, QPT, VST properties’ characteristics tables) and Applications as the “Theasis” extension for ArcGIS (live orthophotos viewing), the DTM and DSM/DEM the official forestry land-use information and the 3d web-API access. The Project is under development and property data is available only in certain areas, mostly residential. Voula is not one of them (one of the reasons it was picked). Buildings were registered only in the first pilot projects even them are not updated any more (last update ~1995) - From the Municipalities of Chalandri and Voula, data acquired consists of City Boundaries / Urban Units, City Blocks, Parcels, Buildings, Terms of building (building coefficients etc), Land Use, Points of Interest, Public Transportation, Public Utilities, Open Spaces, Educational/Athletic/Religion Premises, Lots of geographic and consistency problems - The rest of the important contributors are the Hellenic Statistical Authority (from 2001 census) with GIS data 1/5000 scale: blocks, buildings, road axis, GIS data 1/50000 scale: districts, municipalities, settlements and statistical data, demographics, indices etc, the Hellenic Mapping & Cadastral Organization with Orthophotos of scale 1/500, taken in 2010, Administrative Boundaries of all levels and Corine Land Cover land-use polygons, the Athens Urban Transport Organization, with routes and stations of all public transportation and geodata.gov.gr with all kinds of free geographic data. During the Data Process and Edit, the Coordinate and the Reference System were defined and modified as the Greek Geodetic Reference System 1987 (GGRS87) on the Geodetic Reference System 1980 (GRS80) ellipsoid. All geographic data has been registered in Oracle Spatial 11g, while ArcGIS 10.0 & Geomedia Pro 6.1 have also been used for data analysis and map production and data was organized in File Geodatabases (GIS gdb & Property gdb). The concept was to use all appraised properties data to build a model and then use this model to appraise all the properties of a geographic region. The two datasets have to be identically setup, using the same factors/parameters. The objective was to gather as many factors (location, area and property) as possible for each property, in order to statistically analyze them and distinguish the statistically significant ones. In order to achieve that, all the properties had to be placed on their geographic location by geocoding them. Commercial Geocoding Database has been used, though the original data needed much work on corrections. Bank of Greece properties’ location data was corrected “by hand”. Cadastral and Municipality properties’ location data was more consistent (with substantial errors though), so a “translation table” was created for each of them (Cadastral address -> NAVTEQ address). Without manual corrections about 75% were “exact match” and 90% were able to get geocoded and acquire geometry. For the rest 10% the main problem was mostly double addresses, when a property had access to two roads. All available data should be appended to the existing properties and all dataset properties were geocoded with the same dataset. All the properties already “carry” some “property characteristics” (floor, area, age, auxiliary spaces etc). Through overlaying with GIS data “area characteristics” are appended (building coefficient, land-use, urban units etc), while through network analysis “spatial factors” are appended (distances from POIs, public transportation stations etc). Trough Oracle spatial analysis, the assessed properties can be matched with the cadastral properties, to append their descriptive data as well Neighbourhood analysis was selected and Regression analysis & Hedonic Pricing model were applied. Stata/IC 10.0 for windows statistical software was used, as well as Ordinary Least Squares (OLS) tool (Spatial Statistics) in ArcGIS10, until now with similar results. This stage is ongoing and expected to be concluded with the completion of the whole project. The operation of the system is meant to function through web-interface with 3 levels of security, access and operations (users, moderators, administrator) Users: - Everybody (General Public) could be in this level with free access, no user identification, taxation information & payments, submission of objections on personal, property or taxation data - Registered Users (Valuers, Engineers, Notaries, Lawyers, R.E. Agents) with controlled password access, with the ability to form queries on mean values of areas or/and property types - Certified Valuation Institutions or Individuals (Body of Sworn-in Valuers, Banks, Certified Valuers (RICS/REV), Insurance Companies) with controlled access following certification, monthly valuations’ submission, queries for specific proper

Inducing Single-Molecule Magnetism in a Family of Loop-of-Loops Aggregates: Heterometallic Mn40Na4 Clusters and the Homometallic Mn-44 Analogue

International audienceThe syntheses, crystal structures, and magnetic properties of a new family of heterometallic Mn40Na4 and homometallic Mn-44 loop-of-loops aggregates are reported. The reactions of [Mn3O(O2CMe)(6)(py)(3)]center dot py with 1,3-propanediol (pdH(2)) and 2-methyl-1,3-propanediol (mpdH(2)) in the presence of NaN3 afforded [Mn10Na(mu(3)-O)(2)(O2CMe)(13)(pd)(6)(py)(2)](4) (1)(4) and [Mn10Na(mu(3)-O)(2)(O2CMe)(13)(mpd)(6)(py)(H2O)](4) (2)(4), respectively. Mn40Na4 complexes (1)(4) and (2)(4) consist of four Mn-10 loops linked through Na+ ions to give a supramolecular aggregate with a saddle-like topology. Magnetic characterization of compound (1)(4) showed that each Mn-10 loop has an S = 4 ground-state spin and displays frequency-dependent in-phase and out-of-phase ac susceptibility signals. It also exhibits hysteresis loops that, however, are not typical of single-molecule magnets (SMMs) due to the existence of interloop interactions between the neighboring Mn-10 units of (1)(4) through the diamagnetic Na+ ions, and also intermolecular interactions between different Mn40Na4 aggregates. The magnetically discrete Mn-44 analogue was targeted with high priority and finally prepared from the reaction of [Mn3O(O2CMe)(6)(py)(3)]center dot py with pdH(2) in the presence of Mn(ClO4)(2)center dot 6H(2)O. The loop-of-loops structure of [Mn-44(mu(3)-O)(8)(O2CMe)(52)(pd)(24)(py)(8)](ClO4)(OH)(3) (3) is essentially identical to those of (1)(4) and (2)(4), with the most significant difference being that the four Na+ ions of (1)(4) and (2)(4) have been replaced with Mn2+ ions. Compound 3 is thus best described magnetically as a Mn-44 cluster. In accord with this description and the stronger exchange coupling between the four Mn-10 loops expected through the connecting Mn2+ ions, magnetic susceptibility measurements revealed that 3 has an S = 6 ground-state spin and displays frequency-dependent in-phase and out-of-phase ac signals. Magnetization vs dc field sweeps on single-crystals of 3 displayed scan rate- and temperature-dependent hysteresis loops confirming that complex 3 is a new SMM, and is thus the second largest Mn cluster and SMM reported to date

alpha-Benzoin Oxime in Higher Oxidation State 3d Metal Cluster Chemistry: Structural and Magnetic Study of a New Mn-9(III) Complex

International audienceThe initial employment of alpha-benzoin oxime (bzoxH(2)) in higher oxidation state 3d metal cluster chemistry has provided access to a new enneanuclear Mn-III complex with an unprecedented metal-core topology consisting of two triangular [Mn-3(mu(3)-O2-)(mu-ON)(3)](4+) fragments connected by a linear [Mn-3(mu-ON)(6)](3+) unit. The Mn-9(III) cluster is antiferromagnetically coupled and has an S=3 spin ground state

A Mn^II₆Mn^III₆ Single-Strand Molecular Wheel with a Reuleaux Triangular Topology: Synthesis, Structure, Magnetism, and DFT Studies

The use of the anion of 3-methyl-1,3,5-pentanetriol (mpt^3–) in manganese carboxylate chemistry has afforded the new Mn^II/III₁₂ cluster [Mn^II₆Mn^III₆(mpt)₆(CH₃CO₂)₁₂(py)₆]·3CH₃CN (<b>1</b>·3CH₃CN). Complex <b>1</b> was isolated in moderate yield by the reaction of Mn­(CH₃CO₂)₂·4H₂O and H₃mpt in a 2.6:1 molar ratio in a solvent mixture of acetonitrile and pyridine. The structure of <b>1</b> consists of alternating [Mn^II₂(CH₃CO₂)₃(py)]⁺ and [Mn^III₂(μ-OR)₂(CH₃CO₂)­(py)]³⁺ dimeric units (three of each dimer), linked at each end by two alkoxo and one acetate bridges; the mpt^3– ligands adopt the η²:η²:η²:μ₄ coordination mode. The overall metal topology of this new Mn₁₂ wheel resembles a guitar plectrum, or a Reuleaux triangle. Complex <b>1</b> displays an unprecedented structural topology, being the first example of a Mn^II₆Mn^III₆ wheel constructed from alternating homovalent dimers and the only known Mn₁₂ loop with the trigonal symmetry of a Reuleaux triangle (all other reported loops were ellipsoids). Variable-temperature, solid-state direct- and alternating-current magnetization studies were carried out on complex <b>1</b>, revealing the presence of antiferromagnetic exchange interactions between the metal ions in the molecule, which lead to a spin ground-state value <i>S</i> = 0; the exchange coupling parameters <i>J</i> were calculated using density functional theory employing a hybrid B3LYP functional

Introducing Dimensionality to the Archetypical Mn₁₂ Single-Molecule Magnet: a Family of [Mn₁₂]_<i>n</i> Chains

The [Mn₁₂O₁₂(O₂CR)₁₆(L₄)] family (R = various; L = terminal ligand) of clusters holds a special place in molecular magnetism; they are the most well-studied single-molecule magnets (SMMs). Targeted linkage of these SMMs has now been achieved for the first time. The resulting chain structures have been confirmed crystallographically, and the magnetic properties, up to 1.14 GPa, and high-field electron paramagnetic resonance spectra have been collected and analyzed

WaterSpy: A High Sensitivity, Portable Photonic Device for Pervasive Water Quality Analysis

In this paper, we present WaterSpy, a project developing an innovative, compact, cost-effective photonic device for pervasive water quality sensing, operating in the mid-IR spectral range. The approach combines the use of advanced Quantum Cascade Lasers (QCLs) employing the Vernier effect, used as light source, with novel, fibre-coupled, fast and sensitive Higher Operation Temperature (HOT) photodetectors, used as sensors. These will be complemented by optimised laser driving and detector electronics, laser modulation and signal conditioning technologies. The paper presents the WaterSpy concept, the requirements elicited, the preliminary architecture design of the device, the use cases in which it will be validated, while highlighting the innovative technologies that contribute to the advancement of the current state of the art