Large Number Of Candidates Research Articles

A simple, quantitative method to infer the minimum atmospheric height of small exoplanets

Amongst the many hundreds of transiting planet candidates discovered by the Kepler Mission, one finds a large number of candidates with sizes between that of the Earth and Neptune. The composition of these worlds is not immediately obvious with no Solar System analog to draw upon and there exists some ambiguity as to whether a given candidate is a rocky Super-Earth or a gas-enveloped Mini-Neptune. The potential scientific value and observability of the atmospheres of these two classes of worlds varies significantly and given the sheer number of candidates in this size-range, there is evidently a need for a quick, simple metric to rank whether the planets have an extended atmosphere or not. In this work, we propose a way to calculate the 'minimum atmospheric height' (R_MAH) using only a planet's radius and mass as inputs. We assume and exploit the boundary condition that the bulk composition of a solid/liquid Super-Earth cannot be composed of a material lighter than that of water. Mass-radius loci above a pure-water composition planet correspond to R_MAH>0. The statistical confidence of a planet maintaining an extended atmosphere can be therefore easily calculated to provide a simple ranking of target planets for follow-up observations. We also discuss how this metric can be useful in the interpretation of the spectra of observed planetary atmospheres.

Mayoral referendums and elections revisited

The office of the directly elected mayor has proved popular among national politicians as a means of modernising and strengthening local government but has proved less popular with local politicians and voters. A total of 51 referendums have been held since 1998. These have provided an opportunity for voters to approve or reject mayoral executives to run their local authorities. In a clear majority of cases the referendum was defeated. Another characteristic of these referendums has been the relatively low turnout, boosted only when the referendum has been timed to coincide with a general election or when all-postal voting has been used. Only 17 areas have introduced mayors and in two of these the post was subsequently abolished following a second referendum vote. It is largely urban-based authorities that have elected mayors. A total of 44 mayoral elections have been held since 2000 and in each of these the winner has been determined by the Supplementary Vote method. Low turnout has again been a characteristic of these elections despite each contest attracting a relatively large number of candidates, although not many women candidates have stood. Labour has won most of the elections although Independents have also performed well. Although it was expected that the voting system might see winning candidates emerge with strong mandates, the reality is that few mayors have been elected with an absolute majority of votes cast. A close examination of eligible second votes shows that a large number are not transferred to either of the two runoff candidates. This suggests extensive voter ignorance about the system being used to select mayors.

Peace: pulsar evaluation algorithm for candidate extraction – a software package for post-analysis processing of pulsar survey candidates

Modern radio pulsar surveys produce a large volume of prospective candidates, the majority of which are polluted by human-created radio frequency interference or other forms of noise. Typically, large numbers of candidates need to be visually inspected in order to determine if they are real pulsars. This process can be labor intensive. In this paper, we introduce an algorithm called PEACE (Pulsar Evaluation Algorithm for Candidate Extraction) which improves the efficiency of identifying pulsar signals. The algorithm ranks the candidates based on a score function. Unlike popular machine-learning based algorithms, no prior training data sets are required. This algorithm has been applied to data from several large-scale radio pulsar surveys. Using the human-based ranking results generated by students in the Arecibo Remote Command enter programme, the statistical performance of PEACE was evaluated. It was found that PEACE ranked 68% of the student-identified pulsars within the top 0.17% of sorted candidates, 95% within the top 0.34%, and 100% within the top 3.7%. This clearly demonstrates that PEACE significantly increases the pulsar identification rate by a factor of about 50 to 1000. To date, PEACE has been directly responsible for the discovery of 47 new pulsars, 5 of which are millisecond pulsars that may be useful for pulsar timing based gravitational-wave detection projects.

Eight new radio pulsars in the Large Magellanic Cloud

We present the discovery of eight new radio pulsars located in the Large Magellanic Cloud (LMC). Five of these pulsars were found from reprocessing the Parkes Multibeam Survey of the Magellanic Clouds, while the remaining three were from an ongoing new survey at Parkes with a high resolution data acquisition system. It is possible that these pulsars were missed in the earlier processing due to radio frequency interference, visual judgment, or the large number of candidates that must be analysed. One of these new pulsars has a dispersion measure of 273 pc cm$^{-3}$, almost twice the highest previously known value, making it possibly the most distant LMC pulsar. In addition, we present the null result of a radio pulse search of an X-ray point source located in SNR J0047.2$-$7308 in the Small Magellanic Cloud (SMC). Although no millisecond pulsars have been found, these discoveries have increased the known rotation powered pulsar population in the LMC by more than 50%. Using the current sample of LMC pulsars, we used a Bayesian analysis to constrain the number of potentially observable pulsars in the LMC to within a 95% credible interval of 57000$^{+70000}_{-30000}$. The new survey at Parkes is $\sim$20% complete and it is expected to yield at most six millisecond pulsars in the LMC and SMC. Although it is very sensitive to short period pulsars, this new survey provides only a marginal increase in sensitivity to long periods. The limiting luminosity for this survey is 125 mJy kpc$^2$ for the LMC which covers the upper 10% of all known radio pulsars. The luminosity function for normal pulsars in the LMC is consistent with their counterparts in the Galactic disk. The maximum 1400 MHz radio luminosity for LMC pulsars is $\sim 1000$ mJy kpc$^2$.

UKCAT does not predict medical school performance, study finds

Scores in the UK clinical aptitude test (UKCAT) do not accurately predict subsequent performance at medical school, indicate the results of a study from the University of Nottingham.1 UKCAT was designed to help medical schools distinguish between the large number of candidates with top grades, but the ability of the UKCAT to select the students best suited to studying medicine has been questioned since its launch. The research aimed to assess whether UKCAT scores accurately predicted student performance in the latter part of the medical course, which is mainly delivered on …

Identification of Multiple Novel Protein Biomarkers Shed by Human Serous Ovarian Tumors into the Blood of Immunocompromised Mice and Verified in Patient Sera

The most cancer-specific biomarkers in blood are likely to be proteins shed directly by the tumor rather than less specific inflammatory or other host responses. The use of xenograft mouse models together with in-depth proteome analysis for identification of human proteins in the mouse blood is an under-utilized strategy that can clearly identify proteins shed by the tumor. In the current study, 268 human proteins shed into mouse blood from human OVCAR-3 serous tumors were identified based upon human vs. mouse species differences using a four-dimensional plasma proteome fractionation strategy. A multi-step prioritization and verification strategy was subsequently developed to efficiently select some of the most promising biomarkers from this large number of candidates. A key step was parallel analysis of human proteins detected in the tumor supernatant, because substantially greater sequence coverage for many of the human proteins initially detected in the xenograft mouse plasma confirmed assignments as tumor-derived human proteins. Verification of candidate biomarkers in patient sera was facilitated by in-depth, label-free quantitative comparisons of serum pools from patients with ovarian cancer and benign ovarian tumors. The only proteins that advanced to multiple reaction monitoring (MRM) assay development were those that exhibited increases in ovarian cancer patients compared with benign tumor controls. MRM assays were facilely developed for all 11 novel biomarker candidates selected by this process and analysis of larger pools of patient sera suggested that all 11 proteins are promising candidate biomarkers that should be further evaluated on individual patient blood samples.

Automated Pipeline for De Novo Metabolite Identification Using Mass-Spectrometry-Based Metabolomics

Metabolite identification is one of the biggest bottlenecks in metabolomics. Identifying human metabolites poses experimental, analytical, and computational challenges. Here we present a pipeline of previously developed cheminformatic tools and demonstrate how it facilitates metabolite identification using solely LC/MS(n) data. These tools process, annotate, and compare MS(n) data, and propose candidate structures for unknown metabolites either by identity assignment of identical mass spectral trees or by de novo identification using substructures of similar trees. The working and performance of this metabolite identification pipeline is demonstrated by applying it to LC/MS(n) data of urine samples. From human urine, 30 MS(n) trees of unknown metabolites were acquired, processed, and compared to a reference database containing MS(n) data of known metabolites. From these 30 unknowns, we could assign a putative identity for 10 unknowns by finding identical fragmentation trees. For 11 unknowns no similar fragmentation trees were found in the reference database. On the basis of elemental composition only, a large number of candidate structures/identities were possible, so these unknowns remained unidentified. The other 9 unknowns were also not found in the database, but metabolites with similar fragmentation trees were retrieved. Computer assisted structure elucidation was performed for these 9 unknowns: for 4 of them we could perform de novo identification and propose a limited number of candidate structures, and for the other 5 the structure generation process could not be constrained far enough to yield a small list of candidates. The novelty of this work is that it allows de novo identification of metabolites that are not present in a database by using MS(n) data and computational tools. We expect this pipeline to be the basis for the computer-assisted identification of new metabolites in future metabolomics studies, and foresee that further additions will allow the identification of even a larger fraction of the unknown metabolites.

The variable hydroxamic acid siderophore metabolome of the marine actinomycete Salinispora tropica CNB-440

The recently sequenced genome of the marine actinomycete Salinispora tropica CNB-440 revealed a high frequency of gene clusters which code for the biosynthesis of known and novel secondary metabolites. Of these metabolites, bioinformatics analysis predicted that S. tropica CNB-440 could potentially biosynthesize, as high affinity Fe(iii) ligands, siderophores from the hydroxamic acid desferrioxamine class (sid1 gene cluster) and the phenolate-thia(oxa)zoli(di)ne class (sid2 and sid4 gene clusters). In this work, we have used Ni(ii)-based immobilized metal ion affinity chromatography (IMAC) to pre-fractionate the hydroxamic acid siderophore metabolome of S. tropica CNB-440 from the secondary metabolome, to reveal low abundance siderophores. LC-MS measurements and electronic absorption spectra from purified extracts incubated with exogenous Fe(iii) revealed eight siderophores from the desferrioxamine class (DFOA2, DFOA1a, DFOA1b, DFOB, DFON, DFOD2, DFOE, DFOD1), which included two constitutional isomers (DFOA1a, DFOA1b), and one new siderophore (DFON), the latter which would require assembly from a combination of 1,5-diaminopentane and 1,6-diaminohexane as diamine substrates. Three additional species (m/zobs 496.14, 792.34 and 804.34) with electronic absorption spectra characteristic of complexes formed between Fe(iii) and hydroxamic acid-type siderophores were evident under some conditions. The signal at m/zobs 792.34 eluted in the hydrophobic region of the reverse-phase LC and correlated with a DFOD1 analogue with a C-terminal branched chain fatty acid ([M + K(+)](+)m/zcalc 792.35), which has been previously identified from marine sediment dwelling Micrococcus luteus KLE1011. The S. tropica CNB-440 hydroxamic acid siderophore metabolome was modulated by culture conditions (pH 7, 22 °C; pH 7, 28 °C; pH 9, 28 °C) designed to simulate the variable marine environment. An increase in temperature at constant pH value showed increased levels of DFOA2 and DFOA1, and decreased levels of DFOB and DFOE. An increase in pH value at constant temperature showed decreased levels of DFOA2 and DFOA1, and increased levels of DFOB, DFON and DFOE. These results indicate that the marine adaptation of S. tropica CNB-440 could involve its ability to select a suite of siderophores from a large number of candidates, which are optimized for the iron microenvironment.

Immune Biomarkers in Predictive and Personalized Medicine

century, as most of the focus has been on funding the application of new markers as single test. Each new round of development of technology has created new and promising data in planning and methodology. We have currently identified a large number of candidates’ biomarkers, including proteins, nucleic acids, metabolites and tumor cells which can be use both as single tests or as multiplex tests such as proteomics, cytomics and genomics. In fact, the most essential way to predict future disease is based on genetics (e.g. Human Genome Project’s) although various validation methods for efficiency and more rigorous clinical trials need to be developed. Let’s imagine the situation when a linguist who is familiar with the alphabet but who does not understand Greek language decides to do the ‘mapping’ of Homer’s book “the Odyssey”, he will probably obtain a combinatorial analysis of data by using a personal computer which it allows him to make a claim that the book is successfully decoded. Nevertheless, this linguist is hardly able to comprehend the essence of the text. For the same reason there are doubts about the ability of the Human Genome Project (HGP) as a means of establishing a link between genes and phenotypes.

Swarm Based Population Seeding of Grammatical Evolution

Evolutionary Algorithms, although powerful, are known to be wasteful and time consuming, requiring the evaluation of a large number of candidates. However the strength of the methodology is their ability to continually optimise the population hopefully ensuring a near optimal final solution. When applied to automatic programming tasks, the same limitations are observed, notably the time taken to develop a solution. An alternate, swarm-based method ‘Grammatical Herding’ suffers from the opposite concerns. Whilst it generates moderate fitness solutions quickly, these candidates often lack the optimisation of solutions generated via an evolutionary approach. This study details a hybrid technique ‘Seeded Grammatical Evolution’ where Grammatical Herding (GH) is used to seed the initial population of a Grammatical Evolution (GE) algorithm, with the result that the final solution is produced faster than one produced by GE alone and more effective (fitter) than one produced by GH. In this paper, we explore the background to the study including the initial work that inspired the approach. We also discuss the design of the algorithm and finally the results. We conclude that the hybrid approach is not only capable of producing a fast solution but also achieves state of the art results on a standard benchmark problem, the Santa Fe Trail.

The Achievements of Engineering Master’s Coursework Students from Diverse Backgrounds

The objective of this study is to investigate the performance of postgraduate students from various backgrounds on the basis of the following criteria: country, achievements during undergraduate study, English language requirement and previous work experience. The Civil Engineering Master’s Programme was taken as a case study. A data set sourced from students’ application forms and academic record for three consecutive session intakes, 2008/2009, 2009/2010 and 2010/2011, was used. As a measure of the students’ performance, Graduate Cumulative Grade Point Average (GCGPA) was considered as the key performance index. Students from Malaysia (28%), Iran (53%) and Iraq (19%) were chosen because their communities together represent the largest number of students in Malaysia. The mean achievements of the students from Malaysia, Iran and Iraq were comparable (mean GCGPA 3.52–3.60). The largest number of candidates (43.5%) who entered the programme had an Undergraduate Cumulative Grade Point Average (UCGPA) higher than 2.70 but lower than 3.00. The decision to continue the master’s study was most popular with students 1–4 years after graduation. Regarding the extent to which UCGPA contributed towards GCGPA, Malaysian students exhibited a weak relationship but a stronger correlation than the other student groups (r=0.331, p<0.05). For Iranian students, work experience was very significant (r=0.416, p<0.05). The results also indicate that English proficiency affected the performance of the students. The correlation between work experience and GCGPA differed for students with and without TOEFL/IELTS scores. It is hoped that the results of this work can contribute toward a more detailed study for determining the entry requirements of students seeking admission to master’s course programmes.

Background Factors Contributing to Performance of Master Course Students - Case Study of Civil Engineering Master Programme

The objective of this study is to investigate the performance of the postgraduate students from various backgrounds on the basis of the following criteria: country, achievements during undergraduate study, English language requirement and previous work experience. The Civil Engineering Master Programme was taken as a case study. A data set sourced from students’ application forms and academic record for three consecutive session intakes, 2008/2009, 2009/2010 and 2010/2011, was used. As a measure of the students’ performance, Graduate Cumulative Grade Point Average (GCGPA) was considered as the key performance index. The students from Malaysia (28%), Iran (53%) and Iraq (19%) were chosen since their community represents the largest number of students. The mean achievement of all students from Malaysia, Iran and Iraq was comparable (mean GCGPA 3.52– 3.60). The largest number of candidates (43.5%) who came into the programme were students with higher than 2.70 but lower than 3.00 of Undergraduate Cumulative Grade Point Average (UCGPA). The decision to continue the master study was most popular to those after 1–4 years of graduation. The extent to which UCGPA contributes towards GCGPA, Malaysian students show a weak relationship but has the strongest correlation than the rest (r=0.331, p<0.05). For Iranian students, work experience becomes very significant (r=0.416, p<0.05). The results also indicate that English proficiency affects students performance. It is indicated that correlation between work experience and GCGPA differs for students with and without TOEFL/IELTS scores. It is hoped that the results of this work can help in a more detailed study for determining the entry requirements for students seeking admission to the master course programmes.

Was Duverger Correct? Single-Member District Election Outcomes in Fifty-three Countries

In districts where only one seat is contested, the electoral formula (plurality or majority) should be a major determinant of the number of parties that receive votes. Specifically, plurality rule should generate two-party competition while other institutional arrangements should generate electoral fragmentation. Yet tests of these propositions using district-level data have focused on a limited number of cases; they rarely contrast different electoral systems and have reached mixed conclusions. This study analyses district-level data from 6,745 single-member district election contests from 53 democratic countries to test the evidence for Duverger's Law and Hypothesis. Double-ballot majoritarian systems have large numbers of candidates, as predicted, but while the average outcome under plurality rule is generally consistent with two-party competition, it is not perfectly so. The two largest parties typically dominate the districts (generally receiving more than 90 per cent of the vote), and there is very little support for parties finishing fourth or worse. Yet third-place parties do not completely disappear, and ethnic divisions shape party fragmentation levels, even under plurality rule. Finally, institutional rules that generate multiparty systems elsewhere in the country increase electoral fragmentation in single-member plurality districts.

Stability competition between the layered and compact Cu16 clusters

Copper clusters experience a shape variation from layered to compact at the aggregation number of N = 16. Based on an extensive search for the structures of the low-lying neutral and charged isomers of Cu16 clusters, we address in this study the challenge in a structure search for clusters at shape-variation sizes, which arises from the structural diversity of the low-lying isomers. In order to reduce the bias on the structures with different shapes, a multi-step approach with a large number of candidates is applied to screen the structure pools which are necessarily larger than usual structure search of other sizes. In addition to the previously reported layered and compact structures, a third kind of structure, which can be recognized as a hybrid of layered and compact structures, is identified. Moreover, one of these hybrid structures is predicted to be most stable among the isomers. These hybrid structures not only bridge the structural and electronic properties of the distinct layered and compact structures, but also help understand the growth pattern of copper clusters. A set of new structures of anionic and cationic Cu16 isomers is also presented, starting from the newly established structure pool. The computed properties based on the identified neutral and ionic ground-state structures agree well with the available experimental data.

Fermi-LAT constraints on the pulsar wind nebula nature of HESS J1857+026

Since its launch, the Fermi satellite has firmly identified 5 pulsar wind nebulae plus a large number of candidates, all powered by young and energetic pulsars. HESS J1857+026 is a spatially extended gamma-ray source detected by H.E.S.S. and classified as a possible pulsar wind nebula candidate powered by PSR J1856+0245. We search for gamma-ray pulsations from PSR J1856+0245 and explore the characteristics of its associated pulsar wind nebula. Using a rotational ephemeris obtained from the Lovell telescope at Jodrell Bank Observatory at 1.5 GHz, we phase-fold 36 months of gamma-ray data acquired by the Large Area Telescope (LAT) aboard Fermi. We also perform a complete gamma-ray spectral and morphological analysis. No gamma-ray pulsations were detected from PSR J1856+0245. However, significant emission is detected at a position coincident with the TeV source HESS J1857+026. The gamma-ray spectrum is well described by a simple power-law with a spectral index of 1.53 \pm 0.11_{\rm stat} \pm 0.55_{\rm syst}$ and an energy flux of $G(0.1$--100 GeV$)=(2.71 \pm 0.52_{\rm stat} \pm 1.51_{\rm syst}) \times 10^{-11}$ ergs cm$^{-2}$ s$^{-1}$. The $\gamma$-ray luminosity is $L_{PWN}^{\gamma} (0.1$--100 GeV$)=(2.5 \pm 0.5_{stat} \pm 1.5_{syst}) \times 10^{35} (\frac{d}{9 kpc})^2$ ergs s$^{-1}$, assuming a distance of 9 kpc. This implies a $\gamma-$ray efficiency of $\sim$ 5% for $\dot{E}=4.6 \times 10^{36}$ erg $s^{-1}$, in the range expected for pulsar wind nebulae. Detailed multi-wavelength modeling provides new constraints on its pulsar wind nebula nature.

Energy-Efficient Boundary Monitoring for Large-Scale Continuous Objects

For monitoring of a large-scale continuous object, a large number of sensor nodes might be participated with object detection and tracking. In order to reduce huge quantities of data from the sensor nodes, previous studies focus on representative selection for data reporting to a sink. However, they simply choose representatives among a large number of candidates without consideration of node deployment environments and detection accuracy. Hence, this letter proposes a novel object tracking scheme that first makes a small set of candidates and then chooses a small number of representatives in the set. Also, since the scheme also considers object alteration for representative selection, it can provide high energy-efficiency despite reducing data reporting.

Bioinformatic analyses to select phenotype affecting polymorphisms in HTR2C gene

Single nucleotide polymorphisms (SNPs) in serotonin related genes influence mental disorders, responses to pharmacological and psychotherapeutic treatments. In planning association studies, researchers that want to investigate new SNPs have to select some among a large number of candidates. Our aim is to guide researchers in the selection of the most likely phenotype affecting polymorphisms. Here, we studied serotonin receptor 2C (HTR2C) SNPs because, till now, only relatively few of about 2000 are investigated. We used the most updated and assessed bioinformatic tools to predict which variations can give rise to biological effects among 2450 HTR2C SNPs. We suggest 48 SNPs that are worth considering in future association studies in the field of psychiatry, psychology and pharmacogenomics. Moreover, our analyses point out the biological level probably affected, such as transcription, splicing, miRNA regulation and protein structure, thus allowing to suggest future molecular investigations. Although few association studies are available in literature, their results are in agreement with our predictions, showing that our selection methods can help to guide future association studies.

A DATA ENVELOPMENT ANALYSIS (DEA) EVALUATION METHOD BASED ON SAMPLE DECISION MAKING UNITS

Most of evaluation methods on large number of candidates are based a single criterion. To bring the multiple attribute evaluation method Data Envelopment Analysis (DEA) into evaluating large number of elements, it needs to set up the performance standards and an evaluation procedure by the DEA model. In this paper, we first determine a set of "standard" candidates, called in decision making units (DMUs) in the DEA terminology. This standard set is called "training set". We then establish the evaluation procedure based on this "training set" for measuring a large number of DMUs. We first investigate the efficiency evaluation of a new DMU along with the original definition based on the sum formed production possibility set which is formed by the n DMUs in the training set and the new DMU. We then identify the intersection form of the production possibility set formed only by the n DMUs from the training set. And show that the new DMU evaluation is simply to check if the DMU satisfies a set of linear inequalities. The intersection formed production possibility set formed by the n DMUs from the training set is fixed for evaluating any new DMU. Therefore, it provides an efficient and effective method for dealing with a large amount of data. The method can be regarded as a complementary approach for data mining.

Sub‐population analysis of human cancer vaccine cells—ultra scale‐down characterization of response to shear

The allogeneic whole cell therapy field presents a novel challenge for cell line selection. Large numbers of candidates will he screened for desirable traits including cell growth rates and maintenance of critical product attributes. Screening cell lines for susceptibility to large scale processing conditions has become of increasing importance; innovators do not wish to face the quandary of clinically efficacious cell lines that show poor manufacturability. We have previously described an ultra scale-down method for assessing the impact of the hydrodynamic environment on human cells (McCoy et al., 2009). This body of work describes the validation of this experimental approach using a second, clinically tested, human prostate cancer cell line and describes an additional level of sub-population characterisation. The small-scale conditions set were similar to those expected in downstream process, formulation and vial filling operations with maximum shear rates ranging from 30 x 10(3) to 90 x 10(3) s(-1)(equivalent maximum power dissipation rates of 1.5 x 10(3) to 14 x 10(3) W kg(-1)). Changes to critical cell quality attributes such as membrane integrity retention, cell surface marker staining levels (CD9, CD59, CD147) and cell surface marker density is described. Evaluation of two sub-populations which are formed in response to shear showed distinct staining profiles. Identification of these phenotypically distinct populations, derived in response to the same hydrodynamic environment, poses an interesting bio-processing challenge with regards to both maintenance of product quality, but also highlights the potential benefit of process manipulation through shear-rate intervention with regards to product efficacy.

Abstract 5504: Development of screening system for Brain Tumor Stem Cell-targeting chemotherapeutic agents

Abstract Introduction: Malignant glioma remains one of the most devastating diseases despite recent advances in therapies. Standard of care for malignant gliomas consists of maximal surgical resection, followed by external radiation with concurrent chemotherapy with temozolomide. Unfortunately, tumor recurrence is essentially inevitable and most of the therapies have only limited effects on the survival of patients experiencing tumor recurrence or progression. Emerging evidence has indicated that Brain Tumor Stem Cells (BTSC) can be the specific target of therapy and that elimination of BTSC will most likely result in the growth arrest of the entire tumor mass and the prevention of recurrence. The current therapies, however, preferentially target non-stem tumor cells. Thus, identification of BTSC-specific drugs is highly recommended in order to eradicate the entire tumor cells. To discover the prospective compounds from a large number of candidates efficiently, we have developed here the screening system for BTSC-targeting chemotherapeutic agents. Candidate compounds are screened in a stepwise manner based on their inhibitory potential against BTSC by using several in vitro and in vivo preclinical assays. Being different from the conventional compound discovery procedure, we combine multiple assays aiming at detection of the drugs directly targeting BTSC. Thus, this system functions as a rational agent-prioritization process essential for future progress in developing effective novel cancer treatments. Experimental Approach: We use several human BTSC cultures derived from surgical specimens. These samples have been confirmed to be clonogenic and multipotent in culture, and tumorigenic by xenotransplantation in immunodeficient mice brains. To assess the effect of compounds, the initial step is to use clonogenic assay, cell survival and migration assays with slice cultures of mouse brains, and xenotransplantation of pretreated BTSC. Potential compounds are then processed to the in vivo efficiency and efficacy validation assays using the following animal models, 1. BTSC-derived mouse brain tumor model: patient-derived BTSC transplanted in the mouse brain, 2. Genetically-engineered spontaneous mouse brain tumor model, and 3. Subcutaneous xenograft model of surgical specimens of brain tumor tissues: tumor tissue from patient directly transplanted subcutaneously into immunodeficient mice. Effect of the treatment on tumor progression is monitored by several imaging modalities including microMRI, SPECT/CT, and PET/CT. We also carry out pharmacokinetics profiling to determine the serum levels of the tested compounds and the maximum tolerated dose evaluation to determine their toxicities in comparison to their antitumor activities. In this presentation, we describe the strengths and limitations of each of our assays and also our data with the leading compounds from the previous screening. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5504.