200 research outputs found
Towards understanding the impacts of congestion pricing on urban trucking
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2005.Includes bibliographical references (p. 107-111).Understanding policy impacts on freight is essential for planners who have overlooked this transport group in the past and must evaluate new congestion alleviation policies with respect to regional economic and social goals. Since urban areas are limited in infrastructure expansion and travel demand continues to rise, congestion pricing is a potentially compelling policy alternative. This thesis focuses on measuring the impacts of congestion pricing policies on urban freight. We differentiate from prior studies which measure the impacts of urban freight and present tools to measure the impacts on urban freight according to three stakeholder groups: shippers, carriers, and the public sector. We recognize that the impacts of urban freight may be the motivators for policy change or project implementation and the continued study of these impacts is critical to the public sector who aims to minimize externalities of increasing truck traffic (and is also an urban freight stakeholder); however, we suggest that the impacts that these projects or polices have on freight is particularly important given the economic value associated with goods movement. For each of these stakeholder groups, we evaluate their goals, enumerate the possible responses to the scheme, and provide tools to quantify the impacts. First, we summarize the experiences of urban freight in other congestion pricing schemes and review several implementation decisions from the perspective of freight stakeholders. Second, we characterize possible freight responses to transportation improvement policies. Third, we expand previous freight impact analyses by quantifying the first-order impacts of the scheme for each stakeholder group.(cont.) Finally, we propose additional research extensions related to analyzing the higher-order impacts of freight and using the methods here as a means to introduce public- and private-sector collaboration.by Janine M. Waliszewski.S.M
Anatomy of Malicious Singularities
As well known, the b-boundaries of the closed Friedman world model and of
Schwarzschild solution consist of a single point. We study this phenomenon in a
broader context of differential and structured spaces. We show that it is an
equivalence relation , defined on the Cauchy completed total space
of the frame bundle over a given space-time, that is responsible for
this pathology. A singularity is called malicious if the equivalence class
related to the singularity remains in close contact with all other
equivalence classes, i.e., if for every . We
formulate conditions for which such a situation occurs. The differential
structure of any space-time with malicious singularities consists only of
constant functions which means that, from the topological point of view,
everything collapses to a single point. It was noncommutative geometry that was
especially devised to deal with such situations. A noncommutative algebra on
, which turns out to be a von Neumann algebra of random operators,
allows us to study probabilistic properties (in a generalized sense) of
malicious singularities. Our main result is that, in the noncommutative regime,
even the strongest singularities are probabilistically irrelevant.Comment: 16 pages in LaTe
Mechanical Fatigue Resistance of Polydiketopyrrolo‐Pyrrole‐Dithienylthieno[3,2‐b]thiophene‐Based Flexible Field‐Effect Transistors
MODULADORES HORMONALES AMBIENTALES Y SALUD HUMANA
Los contaminantes ambientas presentes en el entorno humano debido a su resistencia a la degradación, bioacumulación y ubicuidad pueden producir efectos tóxicos inesperados afectando a la salud humana. A este grupo de compuestos, pertenecen los organoclorados que incluyen los insecticidas organoclorados. Ellos pueden interferir en el balance hormonal, actuando como disruptores o moduladores que cambian la homeostasis hormonal. Su actividad considera una posible interacción con el receptor estrogénico, acción antiandrogénica o el cambio en el metabolismo del estradiol que aumenta la producción de metabolitos con mayor fuerza al receptor estrogénico. Esto produce una acelerada proliferación celular y la probabilidad de desarrollar neoplasias. Abstract The environmental pollutants presented in the human environment, due to the persistence, bioaccumulation and ubiquity can cause toxic effects affecting human health. To the group of compounds belong organochlorine that include the organochlorine pesticides. These compounds can interfere with hormone balance, acting as disrupter’s o modulators that changed hormonal homeostasis. Their activity considers the possible interaction with estrogen receptor, action as antiandrogenic or by change in estradiol metabolism that increase metabolite production with higher reactivity to estrogen receptor. The effect results in accelerated cell proliferation and probability to neoplasm development. Palabras clave: compuestos organoclorados, moduladores hormonales
Self-Aligned Bilayers for Flexible Free-Standing Organic Field-Effect Transistors
[Image: see text] Free-standing and flexible field-effect transistors based on 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene)/polystyrene bilayers are obtained by well-controlled phase separation of both components. The phase separation is induced by solvent vapor annealing of initially amorphous blend films, leading to crystallization of TIPS-pentacene as the top layer. The crystallinity and blend morphology strongly depend on the molecular weight of polystyrene, and under optimized conditions, distinct phase separation with a well-defined and trap-free interface between both fractions is achieved. Due to the distinct bilayer morphology, the resulting flexible field-effect transistors reveal similar charge carrier mobilities as rigid devices and additionally pronounced environmental and bias stress stabilities. The performance of the flexible transistors remains stable up to a strain of 1.8%, while above this deformation, a close relation between current and strain is observed that is required for applications in strain sensors
TEJIDO ADIPOSO: INDICADOR DE LA CONTAMINACIÓN POR PLAGUICIDAS ORGANOCLORADOS
Los insecticidas organoclorados, los de mayor importancia por sus propiedades de biomagnificación en la cadena trófica, son el DDT, su metabolito el DDE y el isómero -HCH. Las rutas de ingreso al organismo humano de los plaguicidas persistentes comprenden la inhalación de sus vapores y la ingesta de alimentos contaminados. El monitoreo de tejidos humanos proporciona datos sobre la dosis acumulativa durante eltranscurso del tiempo, a través de todas las rutas ambientales de exposición. El tejido adiposo se ha seleccionado como el idóneo en los estudios de monitoreo, ya que esta compuesto de una gran cantidad de grasa neutra y por la capacidad de almacenar los plaguicidas persistentes.Palabras clave: tejido adiposo, bioindicador, plaguicidas organocloradosadipose tissue,bioindicator, organochlorine pesticide
Role of oxygen within end group substituents on film morphology and charge carrier transport in thiophene/phenylene small-molecule semiconductors
In this study, the end group polarity of (5,5′)-biphenyl-(2,2’)-bithiophenes (PTTPs) was systematically varied from alkyl (1) to alkoxy (2) with one oxygen atom to glycol (3) with two oxygen atoms while the overall length of the end groups is kept constant. Thin films of the three compounds were sublimated at different substrate temperatures and their morphology, crystallinity and charge carrier transport in field-effect transistors was investigated to draw structure-property relationships for the PTTP derivatives. For all three compounds, the effective charge carrier mobility is improved with higher substrate temperatures at which films with higher crystallinity and larger grains are formed. The effective mobility decreases with higher polarity of the end groups from alkyl to alkoxy and glycol. The reliability factor of the alkyl (1) and alkoxy (2) substituted PTTPs decreases with higher substrate temperature, but at the same time this value is enhanced for the glycol substituted molecules (3). The transistors of 3 prepared at higher substrate temperatures also show a reduced threshold voltage and smaller hysteresis in the transfer characteristics. These insights are important for the understanding of the impact of oxygen incorporation into side chain/end group substituents of organic semiconductors and their implementation in organic electrochemical transistors, thermoelectrics and photovoltaics
Systematic Scoring Balloon Lesion Preparation for Drug-Coated Balloon Angioplasty in Clinical Routine: Results of the PASSWORD Observational Study
INTRODUCTION: Scoring balloon angioplasty (SBA) for lumen gain prior to stent implantations or drug-coated balloon angioplasty (DCB) is considered an essential interventional tool for lesion preparation. Recent evidence indicates that SBA may play a pivotal role in enhancing the angiographic and clinical outcomes of DCB angioplasty. METHODS: We studied the systematic use of SBA with a low profile, non-slip element device prior to DCB angioplasty in an unselected, non-randomized patient population. This prospective, all-comers study enrolled patients with de novo lesions as well as in-stent restenotic lesions in bare metal stents (BMS-ISR) and drug-eluting stents (DES-ISR). The primary endpoint was the target lesion failure (TLF) rate at 9 months (ClinicalTrials.gov Identifier NCT02554292). RESULTS: A total of 481 patients (496 lesions) were recruited to treat de novo lesions (78.4%, 377), BMS-ISR (4.0%, 19), and DES-ISR (17.6%, 85). Overall risk factors were acute coronary syndrome (ACS, 20.6%, 99), diabetes mellitus (46.8%, 225), and atrial fibrillation (8.5%, 41). Average lesion lengths were 16.7 +/- 10.4 mm in the de novo group, and 20.1 +/- 8.9 mm (BMS-ISR) and 16.2 +/- 9.8 mm (DES-ISR) in the ISR groups. Scoring balloon diameters were 2.43 +/- 0.41 mm (de novo), 2.71 +/- 0.31 mm (BMS-ISR), and 2.92 +/- 0.42 mm (DES-ISR) whereas DCB diameters were 2.60 +/- 0.39 mm (de novo), 3.00 +/- 0.35 mm (BMS-ISR), and 3.10 +/- 0.43 mm (DES-ISR), respectively. The overall accumulated TLF rate of 3.0% (14/463) was driven by significantly higher target lesion revascularization rates in the BMS-ISR (5.3%, 1/19) and the DES-ISR group (6.0%, 5/84). In de novo lesions, the TLF rate was 1.1% (4/360) without differences between calcified and non-calcified lesions (p = 0.158) and small vs. large reference vessel diameters with a cutoff value of 3.0 mm (p = 0.901). CONCLUSIONS: The routine use of a non-slip element scoring balloon catheter to prepare lesions suitable for drug-coated balloon angioplasty is associated with high procedural success rates and low TLF rates in de novo lesions
Procjena genotoksičnosti insekticida Lannate-90® i njegovih biljnih i životinjskih metabolita u kulturi ljudskih limfocita
This study evaluated direct and metabolic genotoxic effects caused by Lannate-90®, a methomyl-based formulation (90 % active ingredient), in human lymphocyte cultures using sister chromatid exchange assay (SCE). Two processes were used for the plant promutagens evaluation: in vivo activation, applying the insecticide systemically in plants for 4 h and subsequently adding plant metabolites containing extracts to lymphocyte cultures; and in vitro activation, where the insecticide was incubated with Vicia faba S10 mix plus human lymphocyte culture. Direct treatment with the insecticide significantly increased SCE frequency in human lymphocytes (250-750 mg L-1), with cellular death observed at 1000 mg L-1 concentration. Using the extracts of Vicia faba treated with Lannate-90® to treat human lymphocytes, a dose-response relationship was observed. In lymphocyte cultures treated directly with the insecticide for 2 h, a negative response was obtained. When S10 mix was added, SCE frequency did not change significantly. Meanwhile, a mixture of S9 mammalian metabolic mix and Lannate-90® increased the SCE frequency, with an observed concentration-dependent response. Although Lannate-90® induced cellular death at the highest concentrations, it did not cause a delay in cell proliferation in any of the treatments, confirming its genotoxic action. This study is one of the first to evaluate and compare the direct effect of Lannate-90® in two bioassays, animal and vegetal, and the effect of plant and animal metabolism on its genotoxic potential.Korištenjem testa izmjena sestrinskih kromatida (eng. Sister Chromatide Exchange Assay – SCE) u kulturama ljudskih limfocita ispitivani su izravni i metabolički genotoksični učinci insekticida Lannate-90®, formulacije koja se temelji na metomilu (90 % aktivni sastojak). Za procjenu biljnih promutagena provedena su dva postupka: in vivo aktivacija, kod koje se insekticid četiri sata sustavno primjenjivao na biljci, a potom su kulturama limfocita dodani biljni metaboliti s ekstraktom, i aktivacija in vitro, kod koje je insekticid inkubiran mješavinom S10 biljke Vicia faba i kulturom ljudskih limfocita. Izravno tretiranje insekticidom značajno je povećalo učestalost SCE-a u ljudskim limfocitima (250-750 mg L-1), a stanična smrt uočena je pri koncentraciji od 1000 mg L-1. Nakon tretiranja ljudskih limfocita ekstraktima biljke Vicia faba koji su tretirani insekticidom Lannate-90®, primijećen je odnos između doze i učinka. Kod kultura limfocita koje su dva sata bile izravno tretirane insekticidom primijećen je negativan odgovor. Kada je dodana S10 mješavina za metaboličku aktivaciju, učestalost SCE-a nije se značajnije promijenila. Naspram tomu, metabolička mješavina S9 za kultivirane stanice sisavaca i Lannate-90® povećali su učestalost SCE-a, uz zamijećen koncentracijski ovisan odgovor. Premda je Lannate-90® inducirao staničnu smrt pri najvišim koncentracijama, nije uzrokovao zastoj stanične proliferacije ni u jednom postupku, čime se potvrđuje njegovo genotoksično djelovanje. Ovo je ispitivanje među prvima kojim se procjenjivao i uspoređivao izravan učinak insekticida Lannate-90® u dvama biološkim testovima, životinjskom i biljnom, te učinak biljnog i životinjskog metabolizma na njegov genotoksični potencijal
- …