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Local generalized empirical estimation of regression

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Science China Mathematics 2004年第1期47卷 114-127页

作者： Doksum kjell Department of Statistics University of California at Berkeley CA 94720 USA

Letf(x) be the density of a design variableX andm(x) = E[Y∣X = x] the regression function. Thenm(x) = G(x)/f(x), whereG(x) = rn(x)f(x). The Dirac δ-function is used to define a generalized empirical functionG n(x) forG(x) whose expectation equalsG(x). This generalized empirical function exists only in the space of Schwartz distributions, so we introduce a local polynomial of orderp approximation toG n(.) which provides estimators of the functionG(x) and its derivatives. The densityf(x) can be estimated in a similar manner. The resulting local generalized empirical estimator (LGE ) ofm(x) is exactly the Nadaraya-Watson estimator at interior points whenp = 1, but on the boundary the estimator automatically corrects the boundary effect. Asymptotic normality of the estimator is established. Asymptotic expressions for the mean squared errors are obtained and used in bandwidth selection. Boundary behavior of the estimators is investigated in details. We use Monte Carlo simulations to show that the proposed estimator withp = 1 compares favorably with the Nadaraya-Watson and the popular local linear regression smoother.

关键词： boundary adaptive Dirac 5-function local polynomial local empirical Nadaraya-Watson estimator

Repositioning imatinib for spinal cord injury

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Neural Regeneration Research 2015年第10期10卷 1591-1593页

作者： Jacob kjell Lars Olson Department of Neuroscience Karolinska Institutet Department of Physiological Genomics Ludwig-Maximilians-Universität München(LMU)

Efforts to pharmacologically restore central nervous system（CNS）function after injury has historically focused on promoting nerve growth with nerve growth factors such as nerve growth factor（NGF）,neurotrophin 3（... 详细信息

关键词： Repositioning imatinib for spinal cord injury BSCB BBB

Partial Volume Correction in SPECT Using Anatomical Information and Iterative FBP

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Tsinghua Science and Technology 2010年第1期15卷 50-55页

作者： kjell Erlandsson Brian F Hutton The Institute of Nuclear Medicine University College LondonLondonNW12BUUnited Kingdom

The ability to correctly quantify activity concentration with single photon emission computed tomography （SPECT） is limited by its spatial resolution. Blurring of data between adjacent structures, which is known as partial volume effects, can be compensated for by utilizing high resolution structural information from other imaging modalities such as CT or MRI. Previously developed partial volume correction （PVC） methods normally assume a spatially invariant point spread function. In SPECT this is not a good approximation, since the resolution varies with the distance from the collimator. A new method, p-PVC, was developed in this paper, which takes into account the distance dependent blurring. The method operates in projection space and is combined with filtered back-projection （FBP） reconstruction. Results from simulations show that similar quantitative results could be obtained with p-PVC＋FBP as with OSEM with resolution recovery, although with better structural definition and an order of magnitude faster.

关键词： partial volume effect (PVE) partial volume correction (PVC) SPECT

The integrative role of G protein-coupled receptor heterocomplexes in Parkinson’s disease

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Neural Regeneration Research 2022年第10期17卷 2211-2212页

作者： Dasiel O.Borroto-Escuela kjell Fuxe Department of Neuroscience Karolinska InstitutetBiomedicumStockholmSweden

Parkinson’s disease(PD)and its treatment had mainly been focused on the Nigro-striatal dopamine(DA)neurons as the major site of degeneration in this *** contributed to the search for drugs that restored DA transmission in this pathway and contributed to the introduction of L-DOPA and DA receptor agonists in its treatment(Borroto-Escuela and Fuxe,2019).

关键词： drugs treatment Parkinson receptor

Understanding Propagated Sensation along Meridians by Volume Transmission in Peripheral Tissue

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Chinese Journal of Integrative Medicine 2013年第5期19卷 330-339页

作者：张维波赵晏 kjell Fuxe Institute of Acupuncture and Moxibustion China Academy of Chinese Medical Science School of Medicine Xi'an Jiaotong University Department of Neuroscience Karolinska InstitutetStockholm(17177)Sweden

Propagated sensation along meridians （PSM） is a phenomenon that a sensation moves along meridians during stimulation of an acupoint. PSM has an appearance rate of 1.3% among people and have characteristics of low speed, going toward afflicted sites and being blocked by physical pressure which is difficult to be explained by known neural and blood transmission. Volume transmission （VT） is a widespread mode of intercellular communication in the central nervous system that occurs in the extracellular fluid and in the cerebrospinal fluid. VT signals moves from source to target cells via energy gradients leading to diffusion and convection （flow） which is slow, long distance and much less space filling. VT channel diffuse forming a plexus in the extracellular space with two parameters of volume fraction and tortuosity. Some experiments showed an information transmission between adjacent and distant acupoints along meridians cross spinal segments. This process is a cross-excitation between peripheral nerve terminals which is related to nonsynaptic transmission. Some neurotransmitters or neuropeptides such as glutamate, adenosine triphosphate （ATP） and neuropeptide such as substance P, neurokinin A and calcitonin gene-related peptide relate with the cross-excitation which can be regards as VT signals. Comparing the characteristics of PSM and VT, many similar aspects can be found leading to an assumption that PSM is a process of VT in peripheral tissue along meridians. The reason why VT signals transmit along meridians is that the meridian is rich in interstitial fluid under the condition of low hydraulic resistance which has been proven experimentally. According to Darcy＇s law which descript the flow of interstitial fluid and conservation equation, interstitial fluid will move toward meridians and flow along meridians that restrict the VT signals within the channel and accelerate the flow according to Fick＇s diffusion law. During the process, a degranulation of histamine f

关键词： propagated sensation along meridians volume transmission, neurotransmitters and receptors interstitial fluid channel low hydraulic resistance

Volume transmission and receptor-receptor interactions in heteroreceptor complexes:understanding the role of new concepts for brain communication

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Neural Regeneration Research 2016年第8期11卷 1220-1223页

作者： kjell Fuxe Dasiel O.Borroto-Escuela Department of Neuroscience Karolinska Institutet Stockholm Sweden Observatorio Cubano de Neurociencias Grupo Bohio-Estudio Yaguajay Cuba

The discovery of the central monoamine neurons not only demonstrated novel types of brain stem neurons forming global terminal networks all over the brain and the spinal cord,but also to a novel type of communication called volume *** is a major mode of communication in the central nervous system that takes places in the extracellular fluid and the cerebral spinal fluid through diffusion and flow of molecules,like neurotransmitters and extracellular *** integration of synaptic and volume transmission takes place through allosteric receptor-receptor interactions in heteroreceptor *** heterocomplexes represent major integrator centres in the plasma membrane and their protomers act as moonlighting proteins undergoing dynamic changes and their structure and *** fact,we propose that the molecular bases of learning and memory can be based on the reorganization of multiples homo and heteroreceptor complexes into novel assembles in the post-junctional membranes of synapses.

关键词： volume transmission receptor-receptor interaction heteroreceptor complexes oligomerization brain communication learning memory central monoamine neurons

Gastric carcinoid in a patient infected with Helicobacter pylori:A new entity?

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World Journal of Gastroenterology 2011年第25期17卷 3066-3068页

作者： Pantelis Antonodimitrakis Apostolos Tsolakis Staffan Welin Gordana Kozlovacki kjell berg Dan Granberg Department of Medical Sciences Division of Endocrine OncologyUniversity Hospital of Uppsala

There are four types of gastric carcinoid tumors, classified according to their histology and malignant potential. Only a few cases of carcinoid tumors in patients infected with Helicobacter pylori （H. pylor/） have been reported so far. We report a patient infected with H. pylori presenting with a small solitary gastric carcinoid tumor with very low proliferative rate and normal gas- trin levels. The tumor was endoscopically removed and the patient received an eradication therapy against H. pylori. No signs of metastatic disease have been found so far during more than 3 year of follow-up. Infection with H. pylori may cause chronic gastritis with normal or elevated gastrin levels, leading to the develop- ment of gastric carcinoids by mechanisms unrelated to gastrin. Enterochromaffin-like cell tumors related to a chronic H. pylori infection may be considered as a distinct type of gastric carcinoid tumors.

关键词： Gastric carcinoids Gastrin Gastritis Heli-cobacter pylori

Survival and an overview of decision-making in patients with cholangiocarcinoma

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Hepatobiliary & Pancreatic Diseases International 2008年第4期7卷 412-417页

作者： Hvard Mjφrud Forsmo Arild Horn Asgaut Viste Dag Hoem kjell φvrebφ Department of Surgery Haukeland University HospitalBergenNorway Department of Surgical Sciences Haukeland University HospitalBergenNorway

BACKGROUND:Cholangiocarcinoma is rare,accounting for approximately 3%of all gastrointestinal *** study aimed to identify the survival rate among surgically treated and palliated patients,and secondly to identify parameters that could predict a curative resection. METHODS:A total of 121 patients,55 men and 66 women, median age 70 years(range 31-91),who had been treated for cholangiocarcinoma in the period of 1990-2005 were evaluated retrospectively. RESULTS:Curative resection was performed in 40 patients (33%),whereas 81 received palliative treatment(67%).16% (19 of 121)of the patients had an explorative laparotomy without tumour *** above 65 years(OR 3.4;95% CI 1.4-8.4;P=0.008),weight loss(OR 8.5;95%CI 1.5-46; P=0.01)or tumour location(The resection rate of hilar cholangiocarcinoma was lower than that of intrapancreatic cancer.)(OR 2.7;95%CI 1.7-4.5;P=0.001)predicted palliative *** adjusted 5-year survival rate of patients who received tumour resection and palliative treatment was 30%and 1.2%,respectively(P<0.001).The survival rate of patients who were subjected to hepatectomy (70%)was better than that of patients who had a local or distal resection(20%)(P=0.02). CONCLUSIONS:In few patients with a resectable cholangiocarcinoma,an explorative laparotomy is often necessary to evaluate ***,long-term survival is significantly better in patients who received radical surgical resection.

关键词： cholangiocarcinoma survival treatment surgery

Vole preference of bilberry along gradients of simulated moose density and site productivity

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Integrative Zoology 2011年第4期6卷 341-351页

作者： Simen PEDERSEN Harry P.ANDREASSEN Inga-Lill PERSSON Riitta JULKUNEN-TIITTO kjell DANELL Christina SKARPE Department of Forestry and Wildlife Management Hedmark University CollegeKoppangNorway Department of Biology Norwegian University of Science and TechnologyTrondheimNorway Department of Wildlife Fish and Environmental StudiesSwedish University of Agricultural SciencesUmeåSweden Department of Biology University of Eastern FinlandJoensuuFinland

Browsing by large herbivores might either increase or decrease preference for the plant by other herbivores,depending on the plant *** a cafeteria test,we studied the preference by root voles(Microtus oeconomus[Pallas,1776])for bilberry(Vaccinium myrtillus L.)previously subjected to 4 levels of simulated moose(Alces alces[Linnaeus,1758])*** different levels of moose density were simulated at population densities relevant for Fennoscandian conditions,in exclosures situated along a site productivity *** expected:(i)voles to prefer bilberry from high productivity sites over low productivity sites;(ii)voles to prefer browsed bilberry,if plants allocate resources to compensatory growth or to avoid browsed bilberry if plants allocate resources to defense;(iii)these effects to increase with increasing simulated moose density;and(iv)the concentration of plant chemicals and the plant morphology to explain vole ***,we predicted that voles would prefer:(i)plants with high nitrogen content;(ii)plants with low content of defensive substances;and(iii)tall plants with long *** preferred bilberry from the high productivity sites compared to the low productivity *** also found an interaction between site productivity and simulated moose density,where voles preferred unbrowsed plants at low productivity sites and intermediate levels of browsing at high productivity *** was no effect of plant chemistry or morphology on vole *** conclude that moose browsing impacts the food preference of *** the current high densities of moose in Fennoscandia,this could potentially influence vole food selection and population dynamics over large geographical areas.

关键词： browsing cervid herbivory induced defense Microtus