Increasing Electron Transfer Rates with Increasing Donor-Acceptor Distance

Electron transfer can readily occur over long (≥15 Å) distances. Usually reaction rates decrease with increasing distance between donors and acceptors, but theory predicts a regime in which electron-transfer rates increase with increasing donor–acceptor separation. This counter-intuitive behavior can result from the interplay of reorganization energy and electronic coupling, but until now experimental studies have failed to provide unambiguous evidence for this effect. We report here on a homologous series of rigid rodlike donor-bridge-acceptor compounds in which the electron-transfer rate increases by a factor of 8 when the donor–acceptor distance is extended from 22.0 to 30.6 Å, and then it decreases by a factor of 188 when the distance is increased further to 39.2 Å. This effect has important implications for solar energy conversion

Metodbeskrivning : 2020 års inventeringar av gräsmarker och lövskogar

En generell stickprovsdesign, inom vilken det går att inventera både vanliga och ovanliga fenomen på såväl nationell som regional nivå, utvecklades under 2019 och 2020. Under 2020 har den nya stickprovsdesignen använts för inventeringar av gräsmarker och lövskogar med syfte att förbättra nationella data på naturtyper med höga naturvärden, dvs. naturtyper som uppfyller kriterierna för EU:s art- och habitatdirektivs annex 1, samtidigt som vanligare naturtyper följdes där behov funnits för att komplettera befintliga data. I den här rapporten redovisar vi metodiken vi utvecklat för flygbilds- och fältinventeringarna samt hur urval av trakter till stickprov och provytor för fältbesök gått till.För gräsmarks- och lövskogsinventeringarna gjordes först ett gemensamt så kallat balanserat urval för att slumpmässigt välja ut trakter ur urvalsramen till stickprov. Sedan klassades alla provytor inom de utvalda trakterna i en flygbildsinventering till både lövskogs- och gräsmarksklasser. Utifrån de flygbildsinventerade klasserna skapades urvalsklasser separat för gräsmarks- respektive lövskogsinventeringen. Urvalsklasserna användes sedan för att välja ut provytor för fältbesök, ett urval som gjordes för gräsmarks- respektive lövskogsinventeringen oberoende av varandra.Metodiken för flygbildsinventering utvecklades för att gräsmarks- och lövskogsinventeringarna skulle kunna använda stora stickprov, i linje med den nya stickprovsdesignen. En viktig princip vid flygbildsinveteringen var överklassning, dvs att provytor inkluderades där klassningen var osäker. Detta för att säkerställa att alla gräsmarker och lövskogar inom inventeringarnas respektive ramverk hade möjlighet att ingå så att det statistiska kravet för stickprovsdesignen var uppfyllda. Provytor som utifrån flygbildsinventeringen helt säkert inte innehöll eftersökta naturtyper behövde inte besökas i fält vilket gjorde att fältbesöken fokuserades till provytor av intresse för gräsmarks- eller lövskogsinventeringarna. Det minskade kostnaden för fältbesök och vi kunde använda större stickprov. Sammantaget flygbildsinventerades över 137 000 provytor fördelat på 701 trakter inför fältinventeringen 2020.För fältinventeringen inom gräsmarks- och lövskogsinventeringarna introducerades flera nyheter jämfört med tidigare inventeringar för att samla in mer data på bl.a. naturtypers kvalitet. Varje delyta klassades t.ex. till en naturtyp oavsett om den uppfyller kravet för att bli klassad som en annex 1-naturtyp. Utöver det registrerades ett antal kvalitetsvariabler som visar vilka kriterier för annex 1 som är uppfyllda eller inte. Det gör att det går att jämföra areal och statusvariabler för en annex 1-naturtyp) med areal och statusvariabler av motsvarande naturtyp med låga naturvärden (dvs. där annex 1-kriterierna inte är uppfyllda). 1763 provytor fördelat på 187 trakter slumpades ut för att inventeras i fält 2020. Av dem inventerades 64 provytor 2021 eftersom de inte hanns med säsongen 2020.Eftersom antalet trakter är den viktigaste faktorn i att bestämma precisionen i skattningarna så vill vi inte minska antalet trakter eftersom det ökar osäkerheten i skattningarna. För att effektivisera inventeringarna arbetar vi därför med två olika angreppssätt för en viss stickprovstäthet. Dels vill vi förbättra möjligheten att korrekt kunna utesluta provytor, och ibland hela trakter, från fältbesök genom att förbättra flygbildsinventeringen. Det kan t.ex. handla om att minska överklassningen, genom att göra kriterierna för klasserna snävare . Under det första inventeringsåret 2020 tog det lite längre tid att inventera en trakt i fält än vad som var önskvärt. För att minska fälttiden kan vi därför behöva minska antalet provytor som vi inventerar per trakt alternativt förenkla fältmetodiken per provyta. Fältinsatsen kan också bli effektivare genom att inventering av smala linjära objekt, som åker- och vägrenar, görs genom en linjekorsningsinventering istället för via gräsmarks- och lövskogsinventeringarnas provytor. För lövskogsinventeringen 2020 var ålderskriteriet >30 år . Ett sätt att fokusera denna inventering mot naturtyper av större intresse är att höja ålderskriteriet så att inventeringen riktas mer mot äldre lövskogar. Utöver färre provytor skulle det antagligen också leda till att vi behöver besöka färre trakter inom lövskogsinventeringen. Nackdelen blir förstås att inventeringen inte inkluderar yngre skogar, så det är ett beslut som bör tas utifrån vilka frågeställningar som ska besvaras och hur prioriteringen ser ut för vilka data som ska samlas in.För att kunna ta tillvara de möjligheter som den nya stickprovsdesignen ger har vi utvecklat ny metodik för flygbildsinventering av stora stickprov inom gräsmarks- och lövskogsinventeringarna. Det förbättrar våra möjligheter att möta kraven på tillfredställande data även för mer ovanliga naturtyper. För att möta de ökade kraven på data till artikel 17-rapporteringen har vi också utvecklat och omprioriterat fältinventeringen. 2020 var det första året för gräsmarks- och lövskogsinventeringarna. Redan då fanns allt på plats men många delar behöver utvecklas vidare för att ytterligare effektivisera dem

Mode-coupling theory for multiple-time correlation functions of tagged particle densities and dynamical filters designed for glassy systems

The theoretical framework for higher-order correlation functions involving multiple times and multiple points in a classical, many-body system developed by Van Zon and Schofield [Phys. Rev. E 65, 011106 (2002)] is extended here to include tagged particle densities. Such densities have found an intriguing application as proposed measures of dynamical heterogeneities in structural glasses. The theoretical formalism is based upon projection operator techniques which are used to isolate the slow time evolution of dynamical variables by expanding the slowly-evolving component of arbitrary variables in an infinite basis composed of the products of slow variables of the system. The resulting formally exact mode-coupling expressions for multiple-point and multiple-time correlation functions are made tractable by applying the so-called N-ordering method. This theory is used to derive for moderate densities the leading mode coupling expressions for indicators of relaxation type and domain relaxation, which use dynamical filters that lead to multiple-time correlations of a tagged particle density. The mode coupling expressions for higher order correlation functions are also succesfully tested against simulations of a hard sphere fluid at relatively low density.Comment: 15 pages, 2 figure

Impact of first-line cancer treatment on the follicle quality in cryopreserved ovarian samples from girls and young women

STUDY QUESTION: Does first-line chemotherapy affect the quality of ovarian pre-antral follicles and stromal tissue in a population of young patients? SUMMARY ANSWER: Exposure to first-line chemotherapy significantly impacts follicle viability, size of residual intact follicles, steroid secretion in culture and quality of the stromal compartment. WHAT IS KNOWN ALREADY: First-line chemotherapy is considered to have a low gonadotoxic potential, and as such, does not represent an indication for fertility preservation. Studies investigating the effects of chemotherapy on the quality of ovarian tissue stored for fertility preservation in young patients are limited and the results sometimes contradictory. STUDY DESIGN, SIZE, DURATION: We conducted a retrospective cohort study including young patients referred to three centers (Helsinki, Oslo and Tampere) to perform ovarian tissue cryopreservation for fertility preservation between 2003 and 2018. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 43 patients (age 1-24 years) were included in the study. A total of 25 were exposed to first-line chemotherapy before cryopreservation, whereas 18 patients were not. Density and size of follicles divided by developmental stages, prevalence of atretic follicles, health of the stromal compartment and functionality of the tissue in culture were evaluated and related to age and chemotherapy exposure. Activation of dormant follicles and DNA damage were also assessed. MAIN RESULTS AND THE ROLE OF CHANCE: Patients exposed to first-line chemotherapy showed a significantly higher density of atretic primordial and intermediary follicles than untreated patients. The intact primordial and intermediary follicles were significantly smaller in size in patients exposed to chemotherapy. Production of steroids in culture was also significantly impaired and a higher content of collagen and DNA damage was observed in the stromal compartment of treated patients. Collectively, these observations may indicate reduced quality and developmental capacity of follicles as a consequence of first-line chemotherapy exposure. Neither increased activation of dormant follicles nor elevated levels of DNA damage in oocyte nuclei were found in patients exposed to chemotherapy. LIMITATIONS, REASONS FOR CAUTION: The two groups were not homogeneous in terms of age and the patients were exposed to different treatments, which did not allow us to distinguish the effect of specific agents. The limited material availability did not allow us to perform all the analyses on the entire set of patients. WIDER IMPLICATION OF THE FINDINGS: This study provides for the first time a comprehensive analysis of the effects of first-line chemotherapy on the health, density and functionality of follicles categorized according to the developmental stage in patients under 24 years of age. When exposed to these treatments, patients were considered at low/medium risk of infertility. Our data suggest a profound impact of these relatively safe therapies on ovarian health and encourages further exploration of this effect in follow-up studies in order to optimize fertility preservation for young cancer patients.Peer reviewe

Advances for Biomarker Discovery in Neuroproteomics using Mass Spectrometry : From Method Development to Clinical Application

Proteins offer a prominent group of compounds which may be ubiquitously affected in disease and used as biomarkers for early diagnosis, assessing treatment or drug development. Clinical proteomics aim to screen for protein biomarkers by a comprehensive analysis of all proteins expressed in a biological matrix during a certain pathology. Characterization of thousands of proteins in a complex biological matrix is from an analytical point of view a challenging task. Hence, sophisticated methods that are sensitive, specific and robust in a high-throughput manner are required. Mass spectrometry (MS) is able to perform this to a wide extent is. A prominent source for finding protein biomarkers related to neurological diseases is the central nervous system (CNS) due to close proximity of the pathogenesis. Neuroproteomic analysis of CNS tissue samples is thus likely to reveal novel biomarkers. Cerebrospinal fluid (CSF) bathes the entire CNS and offers a good balance between clinical implementation and usefulness. Both matrices put further requirements on the methodology due to a high dynamic range, low protein concentration and limited sample amount. The central objective of this thesis was to develop, assess and utilize analytical methods to be used in combination with MS to enable protein biomarker discovery in the CNS. The use of hexapeptide ligand libraries was exemplified on CSF from patients with traumatic brain injury and demonstrated the ability to compress the dynamic range to enable protein profiling in the order of mg/mL to pg/mL. Further, a method based on cloud-point extraction was developed for simultaneous enrichment and fractionation of hydrophobic/hydrophilic proteins in brain tissue. Comparison between label and label-free MS based strategies were carried out, mimicking the true conditions with a few differentially expressed proteins and a bulk of proteins occurring in unchanged ratio. Finally, a clinical application was carried out to explore the molecular mechanism underlying the analgesic effect of spinal cord stimulation (SCS) in patients with neuropathic pain. The CSF concentration of Lynx1 was found to increase upon SCS. Lynx1, acting as a specific modulator of the cholinergic system in the CNS, may act as a potential important molecular explanation of SCS-induced analgesia

Advances for Biomarker Discovery in Neuroproteomics using Mass Spectrometry : From Method Development to Clinical Application

Proteins offer a prominent group of compounds which may be ubiquitously affected in disease and used as biomarkers for early diagnosis, assessing treatment or drug development. Clinical proteomics aim to screen for protein biomarkers by a comprehensive analysis of all proteins expressed in a biological matrix during a certain pathology. Characterization of thousands of proteins in a complex biological matrix is from an analytical point of view a challenging task. Hence, sophisticated methods that are sensitive, specific and robust in a high-throughput manner are required. Mass spectrometry (MS) is able to perform this to a wide extent is. A prominent source for finding protein biomarkers related to neurological diseases is the central nervous system (CNS) due to close proximity of the pathogenesis. Neuroproteomic analysis of CNS tissue samples is thus likely to reveal novel biomarkers. Cerebrospinal fluid (CSF) bathes the entire CNS and offers a good balance between clinical implementation and usefulness. Both matrices put further requirements on the methodology due to a high dynamic range, low protein concentration and limited sample amount. The central objective of this thesis was to develop, assess and utilize analytical methods to be used in combination with MS to enable protein biomarker discovery in the CNS. The use of hexapeptide ligand libraries was exemplified on CSF from patients with traumatic brain injury and demonstrated the ability to compress the dynamic range to enable protein profiling in the order of mg/mL to pg/mL. Further, a method based on cloud-point extraction was developed for simultaneous enrichment and fractionation of hydrophobic/hydrophilic proteins in brain tissue. Comparison between label and label-free MS based strategies were carried out, mimicking the true conditions with a few differentially expressed proteins and a bulk of proteins occurring in unchanged ratio. Finally, a clinical application was carried out to explore the molecular mechanism underlying the analgesic effect of spinal cord stimulation (SCS) in patients with neuropathic pain. The CSF concentration of Lynx1 was found to increase upon SCS. Lynx1, acting as a specific modulator of the cholinergic system in the CNS, may act as a potential important molecular explanation of SCS-induced analgesia

Advances for Biomarker Discovery in Neuroproteomics using Mass Spectrometry : From Method Development to Clinical Application

Proteins offer a prominent group of compounds which may be ubiquitously affected in disease and used as biomarkers for early diagnosis, assessing treatment or drug development. Clinical proteomics aim to screen for protein biomarkers by a comprehensive analysis of all proteins expressed in a biological matrix during a certain pathology. Characterization of thousands of proteins in a complex biological matrix is from an analytical point of view a challenging task. Hence, sophisticated methods that are sensitive, specific and robust in a high-throughput manner are required. Mass spectrometry (MS) is able to perform this to a wide extent is. A prominent source for finding protein biomarkers related to neurological diseases is the central nervous system (CNS) due to close proximity of the pathogenesis. Neuroproteomic analysis of CNS tissue samples is thus likely to reveal novel biomarkers. Cerebrospinal fluid (CSF) bathes the entire CNS and offers a good balance between clinical implementation and usefulness. Both matrices put further requirements on the methodology due to a high dynamic range, low protein concentration and limited sample amount. The central objective of this thesis was to develop, assess and utilize analytical methods to be used in combination with MS to enable protein biomarker discovery in the CNS. The use of hexapeptide ligand libraries was exemplified on CSF from patients with traumatic brain injury and demonstrated the ability to compress the dynamic range to enable protein profiling in the order of mg/mL to pg/mL. Further, a method based on cloud-point extraction was developed for simultaneous enrichment and fractionation of hydrophobic/hydrophilic proteins in brain tissue. Comparison between label and label-free MS based strategies were carried out, mimicking the true conditions with a few differentially expressed proteins and a bulk of proteins occurring in unchanged ratio. Finally, a clinical application was carried out to explore the molecular mechanism underlying the analgesic effect of spinal cord stimulation (SCS) in patients with neuropathic pain. The CSF concentration of Lynx1 was found to increase upon SCS. Lynx1, acting as a specific modulator of the cholinergic system in the CNS, may act as a potential important molecular explanation of SCS-induced analgesia

Bandwidth Measurement using Performance Counters for Predictable Multicore Software

Memory contention is one of the largest sources of inter-core interference in statically partitioned multicore systems, and the contention reduces the overall performance of applications and causes unpredictable execution-times. A first step in achieving predictable execution is to accurately measure the amount of consumed memory bandwidth for each application. Such measurements can be used to track down bottlenecks, provide better partitioning among cores, and ultimately be used to arbitrate and police access to the memory bus. We propose to use hardware performance counters to continuously track the memory-bandwidth consumed by different applications executing in parallel. In this paper we describe ongoing efforts exploring suitable performance counters on core-level and on system-on-chip level for the 8-core Freescale P4080 processor. The aim is to accurately and efficiently track consumed memory bandwidth per application; with the final goal to use these measurements to improve predictability of multicore real-time software.Submitted for publication to the conference: “Emerging Technologies and Factory Automation (ETFA’12), Poland, September, 2012”This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible. </p