We present searches for quark-lepton compositeness and a heavy W' boson at high electron-neutrino transverse mass. We use approximately 110 pb(-1) of data collected in p p macro collisions at square ...root of s = 1.8 TeV by the CDF Collaboration during 1992-1995. The data are consistent with standard model expectations. Limits are set on the quark-lepton compositeness scale Lambda, the ratio of partial cross sections sigma(W'-->enu)/sigma(W-->enu), and the mass of a W' boson with standard model couplings. We exclude Lambda<2.81 TeV and a W' boson with mass below 754 GeV/c(2) at the 95% confidence level. Combining with our previously published limit obtained using the muon channel, we exclude a W' boson with mass below 786 GeV/c(2) at the 95% confidence level.
The CDF trigger silicon vertex tracker (SVT) Belforte, S.; Dell'Orso, M.; Donati, S. ...
IEEE transactions on nuclear science,
08/1995, Letnik:
42, Številka:
4
Journal Article, Conference Proceeding
Recenzirano
The design is presented for a device presently being built to perform on line track finding and reconstruction for the CDF (Collider Detector at Fermilab) Silicon Vertex Detector (120 k channels). ...This device will provide track impact parameter information for the CDF Level 2 trigger decision, thus allowing CDF to trigger on events containing a long lived particle, in particular a b-quark. It will be the first device with such a capability installed at a proton-antiproton collider. The capability to separate b decays early in the trigger process is vital to the CDF program to collect a high statistic b sample to attack the study of CP violation in the b sector. Moreover SVT will open access to non-leptonic b decays like B/spl rarr//spl pi//spl pi/.< >
Oral Presentations-Abstracts Bartsch, M.; Meijer, D. K. F.; Scherphof, G. L. ...
Critical reviews in biochemistry and molecular biology,
2003, Letnik:
13, Številka:
1
Journal Article
Recenzirano
Targeted Delivery of Antisense Oligodeoxynucleotides In Vivo by Means of Coated Cationic Lipoplexes
Earlier we reported on the massive uptake of liposomes surface-modified with negatively charged ...aconitylated albumin (Aco-HSA) by liver endothelial cells (EC) in vivo. In the present work we apply this principle for in vivo delivery of antisense oligodeoxynucleotides (ODN) to these cells by means of coated cationic lipoplexes (CCL) (1). CCL were prepared by complexing ODN with the cationic lipid DOTAP and subsequent coating of the complex by neutral lipids including a lipid-anchored poly(ethylene glycol). Aco-HSA was covalently coupled.
The Aco-HSA-CCLs were 160 nm in size, contained 1.03 ± 0.35 nmol ODN and 54 ± 18 µg Aco-HSA per µ mol total lipid. The Aco-HSA-CCLs were rapidly eliminated from plasma, 60% of the injected dose being recovered in the liver after 30 m. Within the liver, the EC accounted for two thirds of total liver uptake. Non-targeted CCLs were eliminated very slowly: after 30 m >90% of the particles was in the blood. Currently, we compare the encapsulation efficiency, stability and targetability of the CCL with stabilized antisense lipid particles (SALP) (2), while also the biological activity of these carriers is addressed. In conclusion our results demonstrate that antisense ODN can be targeted very efficiently to EC in vivo, employing plasma-stable CCL, surface modified with negatively charged albumin.
ReferencesStuart DD, Allen TM. BBA 2000; 1463:219-229.Semple S. et al. BBA 2001; 1510: 152-166.
Localisation of Deep Vein Thrombosis Using Drug Delivery System Containing Radioactive Streptokinase
The use of radionuclides as tracers for localisation and identification of deep vein thrombosis has been a subject of much interest in the past several years. A number of research have been performed for localisation of deep vein thrombosis (DVT). Unfortunately, none of these developed agents was used in clinic because of some disadvantages. For this reason, experiments are still going on to develop better radiopharmaceuticals for scintigraphic imaging of DVT. Streptokinase produced by Lancefield Group C β-hemolitic streptococci has been found to induce dissolution of already formed venous and arterial thrombi. Because, the therapeutic use of streptokinase has been reported in the treatment of venous and arterial thrombosis, usefulness of radiolabelled streptokinase a possible agent for localisation of an already formed thrombus has been investigated. But, streptokinase is rapidly removed from circulation so enough amount of streptokinase does not accumulate in thrombi. In this study, streptokinase was entrapped into liposome, niosome and sphingosome dispersions to improve the clot selectivity. Liposome, niosome, sphingosome dispersions containing streptokinase were prepared by film method followed by extrusion and freeze-thawing. 80-91% of activity of enzymes was protected after the preparation when compared with the initial activity. Entrapped drug amount and vesicle size were determined as 10-13% and 150-200 nm, respectively. These systems were tested in an in vivo rabbit model by forming the clots in the jugular vein by injection of thrombin. For biodistribution studies, firstly, RES organs were saturated by injection of empty dispersions to avoid of high uptake of vesicles from RES especially liver. After the injection of free streptokinase and dispersions containing streptokinase, animals were sacrified and RES organs, kidney, lung, vein and thrombus were removed and washed with saline. Then radioactivity of each organs were counted by gamma counter and uptake % per gram organ was calculated for each organ. Important parameter for the biodistribution results was the comparison of the Thrombus Vein ratio. With the entrapment of the streptokinase in the vesicles, thrombus uptake and imaging quality were improved and a high Thrombus Vein ratio was obtained (p<0.05). For scintigraphic imaging studies, after the saturation of RES with empty dispersions, liposome niosome sphingosome dispersions containing streptokinase were injected to the animals. Scintigraphic scans were obtained every 15 m up to 90 m. postadministration. Positive scans indicating uptake of radioactivity were noted as early as 15 m after administration of liposomes containing 99mTc-streptokinase and images quality improved in time. It can be seen from the results of biodistribution studies, liposome niosome sphingosome dispersions containing streptokinase are giving the promising results for the future research. Certainly, further studies are required to improve the quality of scintigraphic images (1).
References
Erdo an S. In vitro and in vivo studies on drug delivery system developed for diagnosis and scintigraphic imaging of deep vein thrombosis, Ph.D. Thesis, Hacettepe University, Ankara, 2001.
Formation of Bilayer Discs in Lysolipid-Containing Thermosensitive Liposomes During Phase Transition: A New Drug Release Mechanism
Lysolipid-containing thermosensitive liposomes (LTSL) containing the anticancer drug doxorubicin (DOX) exhibit superior efficacy in a human tumor xenograft mouse model over lysolipid-free thermosensitive liposomes (TSL) and non-thermosensitive liposomes (NTSL). The reason for this superior efficacy is the increased local drug bioavailability after applying mild hyperthermia to the tumor site resulting in almost instant drug release from LTSL. In the present study, we investigate the drug release mechanism and provide evidence that incorporation of lysolipid in the phospholipid membrane favors the formation of bilayer discs at the phase transition temperature (TC). LTSL and TSL were prepared and kept above TC or cycled trough TC before extrusion. Cryogenic transmission electron microscopy images of samples vitrified above and below TC revealed that bilayer discs were initially not present in the preparation but formed as liposomes were cycled through TC. The amount of bilayer discs increased with the number of TC cycles and was dependent on the presence of lysolipid in the liposomal membrane. The DOX loading capacity decreased with an increasing number of TC cycles and more so in LTSL than in TSL but not in NTSL. We hypothesize that at TC, lysolipids can segregate in phase boundaries between gel-phase plates and adapt a micellar confirmation within the phospholipid bilayer at the rim of bilayer plates. Bilayer discs can then dissociate from liposomes leading to an instant release of the liposomal content. Thus, disc formation may be regarded as a new drug-release mechanism in lysolipid-containing cholesterol-free thermosensitive liposomes.
Liposomal Therapeutics: Process and Formulation Aspects
The literature of liposome science is dominated by the issue of formulation (e.g. lipid composition) and by gross morphological status (e.g. MLV vs. SUV). Relatively less emphasis is placed on production process, process optimization, quality control of raw materials, or in-process and finished product quality control testing. Liposomal preparations of identical composition can exhibit very different performance characteristics depending on process conditions. We will present examples of such process and control issues from Gilead's commercial products AmBisome® (liposomal amphotericin B) and DaunoXome® (liposomal daunorubicin), and from the investigational products MiKasome (liposomal amikacin), NX211 (liposomal lurtotecan), GS7904L (liposomal GW1843U89), and pre-clinical stage liposomal products.
Accelerated Blood Clearance of TRX-Liposomes in Rats and Cynomolgus Monkeys
Accelerated blood clearance of long-circulating liposomes was first reported by Dams et al. (JPET 292:1071-1079, 2000), however, the details of this phenomenon are still unknown. We have developed a novel PEG-liposomal formulation coated with novel cationic lipid (TRX-20). TRX-liposomes have long-circulating characteristics and can target tissues expressing specific types of glycosaminoglycans. In this study, we investigated whether TRX-liposomes show the accelerated blood clearance upon repeated injection. Furthermore, the phenomenon was evaluated in Sprague-Dawley rats and Cynomolgus monkeys to investigate the effect of the species. TRX-liposomes were injected once or twice a week in rats and every two weeks in Cynomolgus monkeys during eight weeks. In rats, the blood concentration of the liposomes one week after first injection were decreased significantly in the both case of injection once a week and twice a week, indicating that the TRX-liposomes showed the phenomenon. The phenomenon, however, attenuated thereafter and disappeared after eight weeks. The phenomenon was independent of injection and total injection of lipid dose. On the other hand, in Cynomolgus monkeys, the plasma concentration profiles of liposomes didn't change during two months. These results suggest that the accelerated blood clearance phenomenon is highly species-specific, probably due to the differences in the immune system between the species.
Uptake and Intracellular Processing of PEG-Liposomes and PEG-Immunoliposomes by Kupffer Cells In Vitro
Specific targeting of drugs to for instance tumors or sites of inflammation may be achieved by means of immunoliposomes carrying site-specific antibodies on their surface. The presence of these antibodies may adversely affect the circulation kinetics of such liposomes as a result of interactions with cells of the mononuclear phagocyte system (MPS), mainly represented by macrophages in liver and spleen. The additional insertion of poly(ethylene glycol) (PEG) chains on the surface of the immunoliposomes may, however, attenuate this effect.
We investigated the influence of surface-coupled rat or rabbit antibodies and of PEG on the uptake of liposomes by rat Kupffer cells in culture with 3H-cholesteryloleyl ether as a metabolically stable marker. Additionally, we assessed the effects of surface-bound IgG and PEG on the intracellular proc
Measurement of the top quark p(T) distribution Affolder, T; Anikeev, K; Antos, J ...
Physical review letters,
2001-Sep-03, 20010903, 2001-09-03, Letnik:
87, Številka:
10
Journal Article
Recenzirano
Odprti dostop
We have measured the p(T) distribution of top quarks that are pair produced in pp collisions at sqrts = 1.8 TeV using a sample of tt decays in which we observe a single high- p(T) charged lepton, a ...neutrino, and four or more jets. We use a likelihood technique that corrects for the experimental bias introduced due to event reconstruction and detector resolution effects. The observed distribution is consistent with the standard model prediction. We use these data to place limits on the production of high- p(T) top quarks suggested in some models of anomalous top quark pair production.
We report on a measurement of the mean charged-particle multiplicity of jets in dijet events with dijet masses in the range 80-630 GeV/c(2), produced at the Tevatron in pp collisions with square root ...(s) = 1.8 TeV and recorded by the Collider Detector at Fermilab. The data are fit to perturbative-QCD calculations carried out in the framework of the modified leading log approximation and the hypothesis of local parton-hadron duality. The fit yields values for two parameters in that framework: the ratio of parton multiplicities in gluon and quark jets, r identical withN(g-jet)(partons)/N(q-jet)(partons) = 1.7+/-0.3, and the ratio of the number of charged hadrons to the number of partons in a jet, K(charged)(LPHD) identical with N(charged)(hadrons)/N(partons) = 0.57+/-0.11.
Phys. Rev. D 98, 112005 (2018) This paper presents a study of the production of a single $W$ boson in
association with one or more jets in proton-antiproton collisions at
$\sqrt{s}=1.96$ TeV, using ...the entire data set collected in 2001-2011 by the
Collider Detector at Fermilab at the Tevatron, which corresponds to an
integrated luminosity of $9.0$ fb$^{-1}$. The $W$ boson is identified through
its leptonic decays into electron and muon. The production cross sections are
measured for each leptonic decay mode and combined after testing that the ratio
of the $W(\rightarrow \mu\nu)+$jets cross section to the $W(\rightarrow
e\nu)+$jets cross section agrees with the hypothesis of $e$-$\mu$ lepton
universality. The combination of measured cross sections, differential in the
inclusive jet multiplicity ($W+\geqslant N$ jets with $N=1,\,2,\,3, \textrm{or
}4$) and in the transverse energy of the leading jet, are compared with
theoretical predictions.
We report on a measurement of the mass dependence of the forward-backward charge asymmetry, A(FB), and production cross section d sigma/dM for e(+)e(-) pairs with mass M(ee)>40 GeV/c(2). The data ...sample consists of 108 pb(-1) of pp macro collisions at square root of s = 1.8 TeV taken by the Collider Detector at Fermilab during 1992-1995. The measured asymmetry and d sigma/dM are compared with the predictions of the standard model and a model with an extra Z' gauge boson.
We present the results of a search for neutral Higgs bosons produced in association with b quarks in pp-->bb(phi)-->bbb final states with 91+/-7 pb(-1) of pp collisions at sqrts = 1.8 TeV recorded by ...the Collider Detector at Fermilab. We find no evidence of such a signal and the data are interpreted in the context of the neutral Higgs sector of the minimal supersymmetric extension of the standard model. With basic parameter choices for the supersymmetric scale and the stop-quark mixing, we derive 95% C.L. lower mass limits for neutral Higgs bosons for tan(beta) values in excess of 35.
We have measured the ratio of prompt production rates of the charmonium states chi(c1) and chi(c2) in 110 pb(-1) of pp collisions at sqrts = 1.8 TeV. The photon from their decay into J/psi(gamma) is ...reconstructed through conversion into e+e- pairs. The energy resolution this technique provides makes the resolution of the two states possible. We find the ratio of production cross sections sigma(chi(c2))/sigma(chi(c1)) = 0.96+/-0.27(stat)+/-0.11(syst) for events with pT(J/psi) > 4.0 GeV/c, /eta(J/psi)/ < 0.6, and pT(gamma) > 1.0 GeV/c.
We present the first measurement of the ratio of branching fractions R identical withB(t-->Wb)/B(t-->Wq) from p_p collisions at sqrts = 1.8 TeV. The data set corresponds to 109 pb(-1) of data ...recorded by the Collider Detector at Fermilab during the 1992-95 Tevatron run. We measure R = 0.94(+0.31)(-0.24)(stat+syst) or R>0.61 (0.56) at 90% (95)% C.L., in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element /V(tb)/ under the assumption of three generations and unitarity.
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