G. Gu - Academia.edu (original) (raw)

Papers by G. Gu

Journal of Neuropathology & Experimental Neurology, 2002

Inhibition of mitochondrial respiratory chain function may contribute to dopaminergic neurodegene... more Inhibition of mitochondrial respiratory chain function may contribute to dopaminergic neurodegeneration in the substantia nigra (SN) of patients with Parkinson disease (PD). Since large-scale structural changes (e.g. deletions and rearrangements in mitochondrial DNA [mtDNA]) have been associated with mitochondrial dysfunction, we tested the hypothesis that increased total mtDNA deletions/rearrangements are associated with neurodegeneration in PD. This study employed a well-established technique, long-extension polymerase chain reaction (LX-PCR), to detect the multiple mtDNA deletions/ rearrangements in the SN of patients with PD, multiple system atrophy (MSA), dementia with Lewy bodies (DLB), Alzheimer disease (AD), and age-matched controls. We also compared the total mtDNA deletions/rearrangements in different brain regions of PD patients. The results demonstrated that both the number and variety of mtDNA deletions/rearrangements were selectively increased in the SN of PD patients compared to patients with other movement disorders as well as patients with AD and age-matched controls. In addition, increased mtDNA deletions/rearrangements were observed in other brain regions in PD patients, indicating that mitochondrial dysfunction is not just limited to the SN of PD patients. These data suggest that accumulation of total mtDNA deletions/rearrangements is a relatively specific characteristic of PD and may be one of the contributing factors leading to mitochondrial dysfunction and neurodegeneration in PD.

Physical Review B, 2014

We present the results of an optical spectroscopic study of two-dimensional atomic crystals of th... more We present the results of an optical spectroscopic study of two-dimensional atomic crystals of the high-temperature superconductor Bi2Sr2CaCu2O 8+δ. Our measurements reveal a pronounced suppression of the optical conductivity σ1(ω) with thickness. Using an effective medium approximation, we interpret this in terms of an insulating surface layer. The surface layer explains the insulating behavior previously observed in exfoliated Bi2Sr2CaCu2O 8+δ and has implications for the potential applications of these materials.

Computer Security - ESORICS 2014, 2014

Advanced false data injection attack in targeted malware intrusion is becoming an emerging severe... more Advanced false data injection attack in targeted malware intrusion is becoming an emerging severe threat to the Supervisory Control And Data Acquisition (SCADA) system. Several intrusion detection schemes have been proposed previously [1, 2]. However, designing an effective real-time detection system for a resource-constraint device is still an open problem for the research community. In this paper, we propose a new relation-graph-based detection scheme to defeat false data injection attacks at the SCADA system, even when injected data may seemly fall within a valid/normal range. To balance effectiveness and efficiency, we design a novel detection model, alternation vectors with state relation graph. Furthermore, we propose a new inference algorithm to infer the injection point(s), i.e., the attack origin, in the system. We evaluate SRID with a real-world power plant simulator. The experiment results show that SRID can detect various false data injection attacks with a low false positive rate at 0.0125%. Meanwhile, SRID can dramatically reduce the search space of attack origins and accurately locate most of attack origins.

Neuroscience Letters, 2009

Acetazolamide has been recognized as an effective treatment for acute mountain sickness. The effi... more Acetazolamide has been recognized as an effective treatment for acute mountain sickness. The efficacy of acetazolamide is related to metabolic acidosis, which promotes chemoreceptors to respond to hypoxic stimuli at altitude. In this study, adult male Sprague-Dawley rats were treated with acetazolamide (100 mg/kg or 50 mg/kg, I.P.) for 3 days. Primary cultured cortical neurons and PC12 cell lines were exposed to acidosis-permissive (pH 6.5) or standard (pH 7.2) media for 20 h. HIF-1␣ and its target genes were assayed by Western blot, real-time PCR, HIF-1 DNA-binding assay and chloramphenicol acetyltransferase reporter gene assay. HIF-1␣ protein level and HIF-1 DNA-binding activities were increased in cerebral cortices of rats treated with acetazolamide. Moreover, the mRNA levels of erythropoietin, vascular endothelial growth factor, and glucose transporter-1 also increased. The HIF-1␣ protein level and activity of HIF-driven chloramphenicol acetyltransferase reporters of cortical neurons and PC12 cells treated with acidosis media were significantly enhanced. We conclude that the normoxic induction of HIF-1␣ and HIF-1 mediated genes by acetazolamide may mediate the effect of acetazolamide in the reduction of symptoms of acute mountain sickness.

Systems & Control Letters, 1992

Two-stage nonlinear algorithms for the problem of identification in ,,~= are analyzed in terms of... more Two-stage nonlinear algorithms for the problem of identification in ,,~= are analyzed in terms of the Fourier transform of the window function. Conditions characterizing the robust convergence of the two-stage nonlinear algorithm are derived. The sufficiency of the conditions holds for a general class of window functions while the necessity is proved for robust convergence of the first stage of the algorithm under the mild additional restriction that the window function is even symmetric. Some improved upper bounds for the worst case identification error are also obtained.

Physics Letters B, 2011

We present evidence for diffractive exclusive dijet production with an invariant dijet mass great... more We present evidence for diffractive exclusive dijet production with an invariant dijet mass greater than 100 GeV in data collected with the D0 experiment at the Fermilab Tevatron Collider. A discriminant based on calorimeter information is used to measure a significant number of events with little energy (typically less than 10 GeV) outside the dijet system, consistent with the diffractive exclusive dijet production topology. The probability for these events to be explained by other dijet production processes is 2 × 10 −5 , corresponding to a 4.1 standard deviation significance.

Physical Review Letters, 2008

We investigated temperature dependent optical spectra of the one-dimensional chain compound Sr 2 ... more We investigated temperature dependent optical spectra of the one-dimensional chain compound Sr 2 CuO 3. The charge transfer transition polarized along the chain direction shows a strongly asymmetric line shape as expected in one-dimensional extended Hubbard model. At low temperature, the charge transfer peak shows a large blueshift and reveals additional sharp peaks at the gap. Even though many spectroscopic studies suggest that this material cannot have a bound exciton based on the one-dimensional extended Hubbard model, we attribute the additional sharp peaks to excitons, which come to exist due to the long-range Coulomb interaction.

Physical Review Letters, 1995

The complete temperature dependences of the in-plane and c-axis microwave (10 6Hz) penetration de... more The complete temperature dependences of the in-plane and c-axis microwave (10 6Hz) penetration depth A(T) and the surface resistance R, (T) of high quality Bi2Sr2Ca|Cu20s+s crystals are reported. In contrast to earlier measurements, a leading A b~T dependence is observed at low temperatures, consistent with nodes in the in-plane gap. The overall behavior of A, q(T) and R"b(T) is similar to that of YBa2Cu30~at low T, but differs at temperatures near T, The c-.axis penetration depth A, (T) is shown to best agree with a model of weakly coupled superconducting layers with nodes in the gap.

Physical Review B, 2008

The spectral properties of a one-dimensional (1D) single-chain Mott insulator Sr2CuO3 have been s... more The spectral properties of a one-dimensional (1D) single-chain Mott insulator Sr2CuO3 have been studied in angle-resolved photoemission and optical spectroscopy, at half filling and with small concentrations of extra charge doped into the chains via high oxygen pressure growth. The singleparticle gap is reduced with oxygen doping, but the metallic state is not reached. The bandwidth of the charge-transfer band increases with doping, while the state becomes narrower, allowing unambiguous observation of separated spinon and holon branches in the doped system. The optical gap is not changed upon doping, indicating that a shift of chemical potential rather than decrease of corelation gap is responsible for the apparent reduction of the photoemission gap.

Physical Review B, 2007

The temperature dependence of the Hall conductivity is reported at mid-and far-IR frequencies for... more The temperature dependence of the Hall conductivity is reported at mid-and far-IR frequencies for cleaved single crystals. A nearly simple Drude behavior is observed with a scattering rate that is linear in temperature and nearly frequency independent. The Hall data are in good agreement with calculations based on the fluctuation-exchange interaction when current vertex corrections are included. The xy quasiparticle spectral weight is suppressed to 0.09 times the band value, compared with 0.33 times the band value for xx .

Physical Review B, 2005

It has been suggested that the maximum magnitude of colossal magnetoresistance occurs in mixed-va... more It has been suggested that the maximum magnitude of colossal magnetoresistance occurs in mixed-valent manganites with a tolerance factor t = 0.96 ͓Zhou, Archibald, and Goodenough, Nature ͑London͒ 381, 770 ͑1996͔͒. However, at t Ϸ 0.96 most manganites have relatively low values of the metal-insulator transition temperature T MI ͑ϳ60-150 K͒. Here, we report that a 50 Å La 0.9 Sr 0.1 MnO 3 thin film with t = 0.96 grown on a ͑100͒ SrTiO 3 substrate has a metal-insulator transition above room temperature, which represents a doubling of T MI compared with its value in the bulk material. We show that this spectacular increase of T MI is a result of the epitaxially compressive strain-induced reduction of the Jahn-Teller distortion.

Journal of Optics, 2011

In this paper, we propose a high-speed three-dimensional (3-D) shape measurement technique for dy... more In this paper, we propose a high-speed three-dimensional (3-D) shape measurement technique for dynamic scenes using geometry-constraint-based number-theoretical phase unwrapping. As a classical algorithm for temporal phase unwrapping (TPU), the number-theoretical approach is suitable for the binary defocusing fringe projection system since it can retrieve an absolute phase without using low-frequency fringe patterns. However, the conventional number-theoretical TPU approach cannot provide sufficient stability to unwrap a high-frequency phase since it requires the two fringe frequencies to be coprime within the global range of the projector coordinate. In contrast, using low-frequency fringe patterns tends to make phase unwrapping more reliable, but at the expense of the measurement precision. By introducing depth constraint into the traditional number-theoretical TPU, we only need to eliminate the phase ambiguity of each pixel within a small period range defined by the depth range, which means that our method just requires the two fringe frequencies to be coprime within the local period range instead of the conventional global range. Due to the reduction of fringe order candidates and the unambiguous phase range, the reliability of phase unwrapping can be significantly improved compared with the traditional number-theoretical TPU approach even when high-frequency fringe patterns are used. The proposed method has been successfully implemented on a high-frame-rate fringe projection system, achieving high-precision, robust, and absolute 3-D shape measurement at 3333 frames per second.

Cancer Research, 2012

The oncoprotein stathmin 1 (STMN1) is upregulated in most, if not all, cancers of epithelial cell... more The oncoprotein stathmin 1 (STMN1) is upregulated in most, if not all, cancers of epithelial cell origin; therefore STMN1 is considered a target for cancer therapy. However, its role during metastasis has not been investigated. Here, we report for the first time that STMN1 strongly inhibits metastatic behavior in both normal epithelial and cancerous epithelial cells. Initially, loss-of-STMN1 compromises cell–cell adhesion. This is followed by epithelial-to-mesenchymal transition (EMT), increased cell migration, and metastasis via cooperative activation of p38 and through TGF-β–independent and -dependent mechanisms. In contrast, expressing STMN1 restores cell–cell adhesion and reverses the metastatic cascade. Primary prostate epithelial cell cultures from benign to undifferentiated adenocarcinoma (UA) clinical biopsies show that EMT-like cells arise while the cancer is still organ-confined and that their emergence is tumor-stage specific. Furthermore, primary EMT-like cells exhibit m...

Cancer Research, 2007

Cancer may arise from a cancer stem/progenitor cell that shares characteristics with its normal c... more Cancer may arise from a cancer stem/progenitor cell that shares characteristics with its normal counterpart. We report the reconstitution of the original human prostate cancer specimen from epithelial cell lines (termed HPET for human prostate epithelial/hTERT) derived from this sample. These tumors can be described in terms of Gleason score, a classification not applied to any of the transgenic mouse models currently developed to mimic human disease. Immunohistochemical and Western blot analyses indicate that they do not express androgen receptor or p63, similar to that reported for prostate stem cells. These cell lines also express embryonic stem markers (Oct4, Nanog, and Sox2) as well as early progenitor cell markers (CD44 and Nestin) in vitro. Clonally derived HPET cells reconstitute the original human tumor in vivo and differentiate into the three prostate epithelial cell lineages, indicating that they arise from a common stem/progenitor cell. Serial transplantation experiments...

In this paper, we propose a statistical theory on measurement and estimation of Rayleigh fading c... more In this paper, we propose a statistical theory on measurement and estimation of Rayleigh fading channels in wireless communications and provide complete solutions to the fundamental problems: What is the optimum estimator for the statistical parameters associated with the Rayleigh fading channel, and how many measurements are sufficient to estimate these parameters with the prescribed margin of error and confidence level? Our proposed statistical theory suggests that two testing signals of different strength be used. The maximum likelihood (ML) estimator is obtained for estimation of the statistical parameters of the Rayleigh fading channel that is both sufficient and complete statistic. Moreover, the ML estimator is the minimum variance (MV) estimator that in fact achieves the Cramér-Rao lower bound.

Science, 2008

Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is... more Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is one of the major outstanding problems in physics. We report local measurements of the onset of superconducting pairing in the high–transition temperature ( T c ) superconductor Bi 2 Sr 2 CaCu 2 O 8+δ using a lattice-tracking spectroscopy technique with a scanning tunneling microscope. We can determine the temperature dependence of the pairing energy gaps, the electronic excitations in the absence of pairing, and the effect of the local coupling of electrons to bosonic excitations. Our measurements reveal that the strength of pairing is determined by the unusual electronic excitations of the normal state, suggesting that strong electron-electron interactions rather than low-energy (<0.1 volts) electron-boson interactions are responsible for superconductivity in the cuprates.

Science, 2008

Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is... more Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is one of the major outstanding problems in physics. We report local measurements of the onset of superconducting pairing in the high–transition temperature ( T c ) superconductor Bi 2 Sr 2 CaCu 2 O 8+δ using a lattice-tracking spectroscopy technique with a scanning tunneling microscope. We can determine the temperature dependence of the pairing energy gaps, the electronic excitations in the absence of pairing, and the effect of the local coupling of electrons to bosonic excitations. Our measurements reveal that the strength of pairing is determined by the unusual electronic excitations of the normal state, suggesting that strong electron-electron interactions rather than low-energy (<0.1 volts) electron-boson interactions are responsible for superconductivity in the cuprates.

Physical Review B, 2012

We report a sequence of continuous phase transformations in iron telluride, Fe1+yTe (y ≈ 0.1), wh... more We report a sequence of continuous phase transformations in iron telluride, Fe1+yTe (y ≈ 0.1), which is observed by combining neutron diffraction, magnetic susceptibility, and specific heat measurements on single crystal samples. While a gradual increase of quasi-elastic magnetic scattering near the wave vector (0.5, 0, 0.5) is seen below T ≈ 70 K, a temperature where the discontinuous first order magneto-structural phase transition is found in systems with small y ( 0.06), the reduction of the lattice symmetry in Fe1.1Te only occurs at Ts ≈ 63 K. Below TN ≈ 57.5 K the long-range magnetic order develops, whose incommensurate wave vector Q m varies with temperature. Finally, at Tm 45 K the system enters the low-T phase, where Q m is locked at ≈ (0.48, 0, 0.5). We conclude that these instabilities are weak compared to the strength of the underlying interactions, and we suggest that the impact of the Fe interstitials on the transitions can be treated with random-field models.

Journal of Neuropathology & Experimental Neurology, 2002

Inhibition of mitochondrial respiratory chain function may contribute to dopaminergic neurodegene... more Inhibition of mitochondrial respiratory chain function may contribute to dopaminergic neurodegeneration in the substantia nigra (SN) of patients with Parkinson disease (PD). Since large-scale structural changes (e.g. deletions and rearrangements in mitochondrial DNA [mtDNA]) have been associated with mitochondrial dysfunction, we tested the hypothesis that increased total mtDNA deletions/rearrangements are associated with neurodegeneration in PD. This study employed a well-established technique, long-extension polymerase chain reaction (LX-PCR), to detect the multiple mtDNA deletions/ rearrangements in the SN of patients with PD, multiple system atrophy (MSA), dementia with Lewy bodies (DLB), Alzheimer disease (AD), and age-matched controls. We also compared the total mtDNA deletions/rearrangements in different brain regions of PD patients. The results demonstrated that both the number and variety of mtDNA deletions/rearrangements were selectively increased in the SN of PD patients compared to patients with other movement disorders as well as patients with AD and age-matched controls. In addition, increased mtDNA deletions/rearrangements were observed in other brain regions in PD patients, indicating that mitochondrial dysfunction is not just limited to the SN of PD patients. These data suggest that accumulation of total mtDNA deletions/rearrangements is a relatively specific characteristic of PD and may be one of the contributing factors leading to mitochondrial dysfunction and neurodegeneration in PD.

Physical Review B, 2014

We present the results of an optical spectroscopic study of two-dimensional atomic crystals of th... more We present the results of an optical spectroscopic study of two-dimensional atomic crystals of the high-temperature superconductor Bi2Sr2CaCu2O 8+δ. Our measurements reveal a pronounced suppression of the optical conductivity σ1(ω) with thickness. Using an effective medium approximation, we interpret this in terms of an insulating surface layer. The surface layer explains the insulating behavior previously observed in exfoliated Bi2Sr2CaCu2O 8+δ and has implications for the potential applications of these materials.

Computer Security - ESORICS 2014, 2014

Advanced false data injection attack in targeted malware intrusion is becoming an emerging severe... more Advanced false data injection attack in targeted malware intrusion is becoming an emerging severe threat to the Supervisory Control And Data Acquisition (SCADA) system. Several intrusion detection schemes have been proposed previously [1, 2]. However, designing an effective real-time detection system for a resource-constraint device is still an open problem for the research community. In this paper, we propose a new relation-graph-based detection scheme to defeat false data injection attacks at the SCADA system, even when injected data may seemly fall within a valid/normal range. To balance effectiveness and efficiency, we design a novel detection model, alternation vectors with state relation graph. Furthermore, we propose a new inference algorithm to infer the injection point(s), i.e., the attack origin, in the system. We evaluate SRID with a real-world power plant simulator. The experiment results show that SRID can detect various false data injection attacks with a low false positive rate at 0.0125%. Meanwhile, SRID can dramatically reduce the search space of attack origins and accurately locate most of attack origins.

Neuroscience Letters, 2009

Acetazolamide has been recognized as an effective treatment for acute mountain sickness. The effi... more Acetazolamide has been recognized as an effective treatment for acute mountain sickness. The efficacy of acetazolamide is related to metabolic acidosis, which promotes chemoreceptors to respond to hypoxic stimuli at altitude. In this study, adult male Sprague-Dawley rats were treated with acetazolamide (100 mg/kg or 50 mg/kg, I.P.) for 3 days. Primary cultured cortical neurons and PC12 cell lines were exposed to acidosis-permissive (pH 6.5) or standard (pH 7.2) media for 20 h. HIF-1␣ and its target genes were assayed by Western blot, real-time PCR, HIF-1 DNA-binding assay and chloramphenicol acetyltransferase reporter gene assay. HIF-1␣ protein level and HIF-1 DNA-binding activities were increased in cerebral cortices of rats treated with acetazolamide. Moreover, the mRNA levels of erythropoietin, vascular endothelial growth factor, and glucose transporter-1 also increased. The HIF-1␣ protein level and activity of HIF-driven chloramphenicol acetyltransferase reporters of cortical neurons and PC12 cells treated with acidosis media were significantly enhanced. We conclude that the normoxic induction of HIF-1␣ and HIF-1 mediated genes by acetazolamide may mediate the effect of acetazolamide in the reduction of symptoms of acute mountain sickness.

Systems & Control Letters, 1992

Two-stage nonlinear algorithms for the problem of identification in ,,~= are analyzed in terms of... more Two-stage nonlinear algorithms for the problem of identification in ,,~= are analyzed in terms of the Fourier transform of the window function. Conditions characterizing the robust convergence of the two-stage nonlinear algorithm are derived. The sufficiency of the conditions holds for a general class of window functions while the necessity is proved for robust convergence of the first stage of the algorithm under the mild additional restriction that the window function is even symmetric. Some improved upper bounds for the worst case identification error are also obtained.

Physics Letters B, 2011

We present evidence for diffractive exclusive dijet production with an invariant dijet mass great... more We present evidence for diffractive exclusive dijet production with an invariant dijet mass greater than 100 GeV in data collected with the D0 experiment at the Fermilab Tevatron Collider. A discriminant based on calorimeter information is used to measure a significant number of events with little energy (typically less than 10 GeV) outside the dijet system, consistent with the diffractive exclusive dijet production topology. The probability for these events to be explained by other dijet production processes is 2 × 10 −5 , corresponding to a 4.1 standard deviation significance.

Physical Review Letters, 2008

We investigated temperature dependent optical spectra of the one-dimensional chain compound Sr 2 ... more We investigated temperature dependent optical spectra of the one-dimensional chain compound Sr 2 CuO 3. The charge transfer transition polarized along the chain direction shows a strongly asymmetric line shape as expected in one-dimensional extended Hubbard model. At low temperature, the charge transfer peak shows a large blueshift and reveals additional sharp peaks at the gap. Even though many spectroscopic studies suggest that this material cannot have a bound exciton based on the one-dimensional extended Hubbard model, we attribute the additional sharp peaks to excitons, which come to exist due to the long-range Coulomb interaction.

Physical Review Letters, 1995

The complete temperature dependences of the in-plane and c-axis microwave (10 6Hz) penetration de... more The complete temperature dependences of the in-plane and c-axis microwave (10 6Hz) penetration depth A(T) and the surface resistance R, (T) of high quality Bi2Sr2Ca|Cu20s+s crystals are reported. In contrast to earlier measurements, a leading A b~T dependence is observed at low temperatures, consistent with nodes in the in-plane gap. The overall behavior of A, q(T) and R"b(T) is similar to that of YBa2Cu30~at low T, but differs at temperatures near T, The c-.axis penetration depth A, (T) is shown to best agree with a model of weakly coupled superconducting layers with nodes in the gap.

Physical Review B, 2008

The spectral properties of a one-dimensional (1D) single-chain Mott insulator Sr2CuO3 have been s... more The spectral properties of a one-dimensional (1D) single-chain Mott insulator Sr2CuO3 have been studied in angle-resolved photoemission and optical spectroscopy, at half filling and with small concentrations of extra charge doped into the chains via high oxygen pressure growth. The singleparticle gap is reduced with oxygen doping, but the metallic state is not reached. The bandwidth of the charge-transfer band increases with doping, while the state becomes narrower, allowing unambiguous observation of separated spinon and holon branches in the doped system. The optical gap is not changed upon doping, indicating that a shift of chemical potential rather than decrease of corelation gap is responsible for the apparent reduction of the photoemission gap.

Physical Review B, 2007

The temperature dependence of the Hall conductivity is reported at mid-and far-IR frequencies for... more The temperature dependence of the Hall conductivity is reported at mid-and far-IR frequencies for cleaved single crystals. A nearly simple Drude behavior is observed with a scattering rate that is linear in temperature and nearly frequency independent. The Hall data are in good agreement with calculations based on the fluctuation-exchange interaction when current vertex corrections are included. The xy quasiparticle spectral weight is suppressed to 0.09 times the band value, compared with 0.33 times the band value for xx .

Physical Review B, 2005

It has been suggested that the maximum magnitude of colossal magnetoresistance occurs in mixed-va... more It has been suggested that the maximum magnitude of colossal magnetoresistance occurs in mixed-valent manganites with a tolerance factor t = 0.96 ͓Zhou, Archibald, and Goodenough, Nature ͑London͒ 381, 770 ͑1996͔͒. However, at t Ϸ 0.96 most manganites have relatively low values of the metal-insulator transition temperature T MI ͑ϳ60-150 K͒. Here, we report that a 50 Å La 0.9 Sr 0.1 MnO 3 thin film with t = 0.96 grown on a ͑100͒ SrTiO 3 substrate has a metal-insulator transition above room temperature, which represents a doubling of T MI compared with its value in the bulk material. We show that this spectacular increase of T MI is a result of the epitaxially compressive strain-induced reduction of the Jahn-Teller distortion.

Journal of Optics, 2011

In this paper, we propose a high-speed three-dimensional (3-D) shape measurement technique for dy... more In this paper, we propose a high-speed three-dimensional (3-D) shape measurement technique for dynamic scenes using geometry-constraint-based number-theoretical phase unwrapping. As a classical algorithm for temporal phase unwrapping (TPU), the number-theoretical approach is suitable for the binary defocusing fringe projection system since it can retrieve an absolute phase without using low-frequency fringe patterns. However, the conventional number-theoretical TPU approach cannot provide sufficient stability to unwrap a high-frequency phase since it requires the two fringe frequencies to be coprime within the global range of the projector coordinate. In contrast, using low-frequency fringe patterns tends to make phase unwrapping more reliable, but at the expense of the measurement precision. By introducing depth constraint into the traditional number-theoretical TPU, we only need to eliminate the phase ambiguity of each pixel within a small period range defined by the depth range, which means that our method just requires the two fringe frequencies to be coprime within the local period range instead of the conventional global range. Due to the reduction of fringe order candidates and the unambiguous phase range, the reliability of phase unwrapping can be significantly improved compared with the traditional number-theoretical TPU approach even when high-frequency fringe patterns are used. The proposed method has been successfully implemented on a high-frame-rate fringe projection system, achieving high-precision, robust, and absolute 3-D shape measurement at 3333 frames per second.

Cancer Research, 2012

The oncoprotein stathmin 1 (STMN1) is upregulated in most, if not all, cancers of epithelial cell... more The oncoprotein stathmin 1 (STMN1) is upregulated in most, if not all, cancers of epithelial cell origin; therefore STMN1 is considered a target for cancer therapy. However, its role during metastasis has not been investigated. Here, we report for the first time that STMN1 strongly inhibits metastatic behavior in both normal epithelial and cancerous epithelial cells. Initially, loss-of-STMN1 compromises cell–cell adhesion. This is followed by epithelial-to-mesenchymal transition (EMT), increased cell migration, and metastasis via cooperative activation of p38 and through TGF-β–independent and -dependent mechanisms. In contrast, expressing STMN1 restores cell–cell adhesion and reverses the metastatic cascade. Primary prostate epithelial cell cultures from benign to undifferentiated adenocarcinoma (UA) clinical biopsies show that EMT-like cells arise while the cancer is still organ-confined and that their emergence is tumor-stage specific. Furthermore, primary EMT-like cells exhibit m...

Cancer Research, 2007

Cancer may arise from a cancer stem/progenitor cell that shares characteristics with its normal c... more Cancer may arise from a cancer stem/progenitor cell that shares characteristics with its normal counterpart. We report the reconstitution of the original human prostate cancer specimen from epithelial cell lines (termed HPET for human prostate epithelial/hTERT) derived from this sample. These tumors can be described in terms of Gleason score, a classification not applied to any of the transgenic mouse models currently developed to mimic human disease. Immunohistochemical and Western blot analyses indicate that they do not express androgen receptor or p63, similar to that reported for prostate stem cells. These cell lines also express embryonic stem markers (Oct4, Nanog, and Sox2) as well as early progenitor cell markers (CD44 and Nestin) in vitro. Clonally derived HPET cells reconstitute the original human tumor in vivo and differentiate into the three prostate epithelial cell lineages, indicating that they arise from a common stem/progenitor cell. Serial transplantation experiments...

In this paper, we propose a statistical theory on measurement and estimation of Rayleigh fading c... more In this paper, we propose a statistical theory on measurement and estimation of Rayleigh fading channels in wireless communications and provide complete solutions to the fundamental problems: What is the optimum estimator for the statistical parameters associated with the Rayleigh fading channel, and how many measurements are sufficient to estimate these parameters with the prescribed margin of error and confidence level? Our proposed statistical theory suggests that two testing signals of different strength be used. The maximum likelihood (ML) estimator is obtained for estimation of the statistical parameters of the Rayleigh fading channel that is both sufficient and complete statistic. Moreover, the ML estimator is the minimum variance (MV) estimator that in fact achieves the Cramér-Rao lower bound.

Science, 2008

Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is... more Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is one of the major outstanding problems in physics. We report local measurements of the onset of superconducting pairing in the high–transition temperature ( T c ) superconductor Bi 2 Sr 2 CaCu 2 O 8+δ using a lattice-tracking spectroscopy technique with a scanning tunneling microscope. We can determine the temperature dependence of the pairing energy gaps, the electronic excitations in the absence of pairing, and the effect of the local coupling of electrons to bosonic excitations. Our measurements reveal that the strength of pairing is determined by the unusual electronic excitations of the normal state, suggesting that strong electron-electron interactions rather than low-energy (<0.1 volts) electron-boson interactions are responsible for superconductivity in the cuprates.

Science, 2008

Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is... more Identifying the mechanism of superconductivity in the high-temperature cuprate superconductors is one of the major outstanding problems in physics. We report local measurements of the onset of superconducting pairing in the high–transition temperature ( T c ) superconductor Bi 2 Sr 2 CaCu 2 O 8+δ using a lattice-tracking spectroscopy technique with a scanning tunneling microscope. We can determine the temperature dependence of the pairing energy gaps, the electronic excitations in the absence of pairing, and the effect of the local coupling of electrons to bosonic excitations. Our measurements reveal that the strength of pairing is determined by the unusual electronic excitations of the normal state, suggesting that strong electron-electron interactions rather than low-energy (<0.1 volts) electron-boson interactions are responsible for superconductivity in the cuprates.

Physical Review B, 2012

We report a sequence of continuous phase transformations in iron telluride, Fe1+yTe (y ≈ 0.1), wh... more We report a sequence of continuous phase transformations in iron telluride, Fe1+yTe (y ≈ 0.1), which is observed by combining neutron diffraction, magnetic susceptibility, and specific heat measurements on single crystal samples. While a gradual increase of quasi-elastic magnetic scattering near the wave vector (0.5, 0, 0.5) is seen below T ≈ 70 K, a temperature where the discontinuous first order magneto-structural phase transition is found in systems with small y ( 0.06), the reduction of the lattice symmetry in Fe1.1Te only occurs at Ts ≈ 63 K. Below TN ≈ 57.5 K the long-range magnetic order develops, whose incommensurate wave vector Q m varies with temperature. Finally, at Tm 45 K the system enters the low-T phase, where Q m is locked at ≈ (0.48, 0, 0.5). We conclude that these instabilities are weak compared to the strength of the underlying interactions, and we suggest that the impact of the Fe interstitials on the transitions can be treated with random-field models.