Van Enk Research Articles

Abstract 655: Fungal extract screening reveals malformin C to preferentially kill glioblastoma stem-like cells via concerted induction of proteotoxic stress and autophagic flux blockade

Abstract Glioblastoma is a highly aggressive brain tumor for which there is no cure. The dire prognosis of this disease is largely attributable to a high level of heterogeneity, including the presence of a sub-population of tumor initiating glioblastoma stem-like cells (GSCs), which are refractory to chemo- and radiotherapy. Here, in an unbiased marine-derived fungal extract screen, together with bioguided dereplication based on high resolution mass spectrometry, we identified malformin C to preferentially induce cell death in patient-derived GSCs, and explore the potential of this cyclic peptide as a therapeutic agent for glioblastoma. Malformin C significantly reduced tumor growth in an in vivo xenograft model of glioblastoma. Using transcriptomics and chemoproteomics, we found that malformin C binds to many proteins leading to aggregation, and rapidly induces unfolded protein response, including autophagy, in GSCs. Malformin C also appears to accumulate in lysosomes, disrupting autophagic flux and driving cells to death. Supporting this, malformin C synergizes with chloroquine, an inhibitor of autophagy. Strikingly, we observed that autophagic flux is differentially regulated in GSCs compared with normal astrocytes. The sensitivity of GSCs to malformin C highlights the relevance of proteostasis and autophagy as a therapeutic vulnerability in glioblastoma. Citation Format: Emma L. Phillips, Sizèd van Enk, Sara Kildgaard, Silja Schlue, Mona Göttmann, Victoria Jennings, Frederic Bethke, Gabriele Müller, Christel Herold-Mende, Daniel Pastor-Flores, Martin Schneider, Dominic Helm, Thomas Ostenfeld Larsen, Violaine Goidts. Fungal extract screening reveals malformin C to preferentially kill glioblastoma stem-like cells via concerted induction of proteotoxic stress and autophagic flux blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 655.

Entangled Coherent States in Teleportation

In the present paper, we will review the methods to produce superposition of entangled coherent state using polarizing beam splitter and Kerr non linearity. These coherent states have many attractive features and can be used in various schemes. Entanglement, refers to the superposition of a multiparticle system and explains a new type of correlations between any two subsystems of the quantum system, which is not existing in the classical physics. The present paper deals with the use of these states in quantum teleportation, entanglement diversion and entanglement swapping schemes. Entanglement diversion and entanglement-swapping refers to a scheme which may entangle those particles which had never interacted before. In the swapping scheme, two pairs of entangled state are taken. One particle from each pair is subjected to a Bell-state-measurement. This would result in projection of the other two outgoing particles in an entangled pair. Quantum Teleportation of two mode and three modes states is also studied with perfect fidelity. Minimum assured fidelity which is defined as the minimum of the fidelity for any unknown quantum information of the states is also discussed. It is also shown how the success rate of teleportation of a superposition of odd and even coherent states can be increased from 50% to almost 100%. The scheme suggested by van Enk and Hirota was modified by Prakash, Chandra, Prakash and Shivani in 2007. We find that an almost teleportation, diversion and swapping is possible by simply separating vacuum state from the even state. The present paper also deals with study of effect of decoherence and noise on these states and the effect of noise on fidelity and minimum assured fidelity. It is also discussed that these schemes can also be applied to the process of entanglement diversion and entanglement swapping.

Is the essence of a quantum game captured completely in the original classical game?

van Enk and Pike (2002), argue that the equilibrium solution to a quantum game is not unique but is already present in the classical game itself. In this work, we contest this assertion by showing that a random strategy in a particular quantum (Hawk–Dove) game is unique to the quantum game. In other words the equilibrium solution of the quantum Hawk–Dove game cannot be obtained in the classical Hawk–Dove game. Moreover, we provide an analytical solution to the quantum 2 × 2 strategic form Hawk–Dove game using random mixed strategies. The random strategies which we describe are Pareto optimal with their payoff’s classically unobtainable. We compare the quantum strategies to correlated strategies and find that correlated strategies in quantum Hawk–Dove game or quantum Prisoner’s dilemma yield the Nash equilibrium solution.

ICRE Top Research Papers.

ICRE Top Research Papers.

Coordinating nominal compounds: Universal vs. areal tendencies

AbstractCoordinating compounds, i.e. complex word forms in which the constituent lexemes are in a coordination relation, may be divided into two classes: hyperonymic, in which the referent of the whole compound is the “sum” of the meanings of the constituent lexemes (Korowaiyumdefól‘(her) husband-wife, couple’; van Enk, Gerrit J., & Lourens de Vries. 1997.The Korowai of Irian Jaya: Their language in its cultural context. Oxford: Oxford University Press: 66), and hyponymic, where the compound designates a single referent having features of all the constituents (Englishactor-director). It has been proposed that languages choose either type as the one with the “tightest” marking pattern; whereas the crosslinguistic tendency is to have tighter hyperonymic compounds, most languages of Europe rather have tighter hyponymic compounds (Arcodia, Giorgio Francesco, Nicola Grandi, & Bernhard Wälchli 2010. Coordination in compounding. In Sergio Scalise & Irene Vogel (eds.),Cross-disciplinary issues in compounding, 177–198. Amsterdam & Philadelphia: John Benjamins). In this paper, we will test this assumption on noun-noun compounds in a sample of 20 Standard Average European languages and in a balanced sample of 60 non-SAE languages, arguing that the preference for hyperonymic compounds is best explained by the default referential function of nouns; in hyponymic compounds, on the other hand, nouns are used to indicate properties. We will then compare nominal and adjectival coordinating compounds, showing that for the latter the hyponymic compounding pattern is the dominant one, as adjectives are prototypical property-denoting words.

Experimental demonstration of loop state-preparation-and-measurement tomography

We have performed an experiment demonstrating that loop state-preparation-and-measurement (SPAM) tomography [C. Jackson and S. J. van Enk, Phys. Rev. A 92, 042312 (2015)] is capable of detecting correlated errors between the preparation and the measurement of a quantum system. Specifically, we have prepared pure and mixed states of single qubits encoded in the polarization of heralded individual photons. By performing measurements using multiple state preparations and multiple measurement device settings we are able to detect if there are any correlated errors between them, and are also able to determine which state preparations are correlated with which measurements. This is accomplished by going around a 'loop' in parameter space, which allows us to check for self-consistency. No assumptions are made concerning either the state preparations or the measurements, other than that the dimensions of the states and the positive-operator-valued measures (POVM) describing the detector are known. In cases where no correlations are found we are able to perform quantum state tomography of the polarization qubits by using knowledge of the detector POVMs, or quantum detector tomography by using knowledge of the state preparations.

Knowing Minds is a Matter of Authority: Political Dimensions of Opacity Statements in Korowai Moral Psychology

Knowing Minds is a Matter of Authority:Political Dimensions of Opacity Statements in Korowai Moral Psychology Rupert Stasch In this essay, I want to set forth briefly the hypothesis that New Guinea people's statements about the opacity of other minds are often statements not only about knowledge and meaning but also about authority. Melanesian sensitivity about not presuming to know others' minds is intertwined with sensitivity about not presuming to impinge on each other's self-determination. Reflexive models of the possibilities and problems of knowing other minds are also models of the political terms of people's coexistence. I make this suggestion based on patterns of talk about minds among Korowai people of the southern lowlands of West Papua. There are about four thousand speakers of Korowai dialects, who live dispersed on clan-owned lands across five hundred square miles of forest, as well as increasingly in centralized villages along the region's major waterways (van Enk and de Vries 1997; Stasch In press). It is a feature of the generally egalitarian, fractious tenor of Korowai collective life that people overtly represent otherness of thoughts as a matter of politics, and politics as a matter of otherness of thoughts. The central item of talk illustrating this point is the commonly-heard [End Page 443] verbal formula yepa yexulmelun, literally "Herself her thoughts," or "Himself his thoughts," an expression closely parallel to canonical statements about opacity of other minds reported from many other New Guinea communities. The word I translate as "thoughts" here, xulmelun, could also be glossed as "thinking," "mind," "intention," "will," "plans," "consciousness," "awareness," "feelings," or "reasoning." The word xulmelun also means "guts" or "viscera." Korowai like many other people identify cognitive and emotional deliberation with spaces of bodily interiority, specifically the internal cavity of a person's torso, and the organs there.1 The statement "Herself her thoughts" or "Himself his thoughts" juxtaposes two noun phrases, which add up to the proposition: "She herself has her own guts," "She thinks for herself," or "She decides for herself." One kind of situation in which I repeatedly heard this statement and variants on it during my fieldwork with Korowai was in reply to my own questions about why some third person had performed a certain action, or about whether a third person would perform a certain action in the future. When I asked interviewees to discuss the motives or future actions of other people in these kinds of ways, my interlocutors routinely replied by disavowing knowledge of other people's thoughts. The assertion "She has her own thoughts" is an argument against an opposite idea people took to be implied in my questions, an idea of mind-reading. In fact, one common variant of the statement that people sometimes put to me means literally " It's not as though our minds are unitary" (xulmelun lelipfano). Plenty of times, though, interviewees did answer my questions about reasons for others' actions with statements of those people's motives, and they answered questions about others' future actions with outright predictions of what those others would do. It seems also that disavowal of telepathy is topic-specific. Korowai persons are highly influenced in their actions by "shame, embarrassment" (xatax) or other feelings of being disparaged by other people. I was often struck by the contrast between people's prominent disavowals of the ability to know others' thoughts on most subjects, and their readiness to attribute to others thoughts of ill-regard toward my interlocutors themselves, without any expressive evidence of such thoughts. For example, interviewees would tell me about being "mocked" (xulmo-) by other people, but then when I questioned them closely it would frequently turn out that this mockery was a mental state attributed to the other persons but not concretely signaled by those persons. It might be fine to claim quasi-telepathic knowledge of someone else's thoughts about one's own [End Page 444] worth, even when it is not fine to presume to know or impinge on that person's own plans and hopes for him- or herself. In this and many other respects, claims to knowledge of other people's motives and intentions are a focus of...

Effect of decoherence on fidelity in teleportation using entangled coherent states

A scheme of teleporting a superposition of coherent states |α⟩ and | − α⟩ using a beam splitter and two phase shifters was proposed by van Enk and Hirota (2001 Phys. Rev. A 64 022313). The authors concluded that the probability for successful teleportation is 1/2. In this paper, it is shown that the authors' scheme can be altered slightly so as to obtain an almost perfect teleportation for an appreciable value of |α|2. For |α|2 = 5, the minimum of average fidelity, which is the minimum of the sum of the product of probability of occurrence of any case, and the corresponding fidelity is less than 1 by a quantity ∼10−4. We also discuss the effect of decoherence on teleportation fidelity. We find that if no photons are counted in both final outputs, the minimum assured fidelity is still non-zero except when there is no decoherence and the information is an even coherent state. For non-zero photon counts, minimum assured fidelity decreases with an increase in |α|2 for low noise. For high noise, however, it increases, attains a maximum value and then decreases with |α|2. The average fidelity depends appreciably on the information for low values of |α|2 only.

Response to Comment on "Quantum State Transfer Between Matter and Light"

The comment by van Enk and Kimble ([ 1 ][1]) does not challenge the principal result of our study ([ 2 ][2])—that we achieved quantum state transfer from an atomic qubit to a photonic qubit. They also do not challenge our quantitative measurement of that transfer ([ 2 ][2]). We used the ratio of

Comment on “Paradoxical behavior of an infinite ladder network of inductors and capacitors,” by S. J. van Enk [Am. J. Phys. 68, 854–856 (2000)

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Decoherence of a two-state atom driven by coherent light

Recent studies of the decoherence induced by the quantum nature of the laser field driving a two-state atom [J. Gea-Banacloche, Phys. Rev. A 65, 022308 (2002); S. J. van Enk and H. J. Kimble, Quantum Inf. and Comp. 2, 1 (2002)] have been questioned by Itano [W. M. Itano, Phys. Rev. A 68, 046301 (2003)] and the proposal made that all decoherence is due to spontaneous emission. We analyze the problem within the formalism of cascaded open quantum systems. Our conclusions agree with the Itano proposal. We show that the decoherence, nevertheless, may be divided into two parts--that due to forwards scattering and to scattering out of the laser mode. Previous authors attribute the former to the quantum nature of the laser field.

Defending continuous variable teleportation: why a laser is a clock, not a quantum channel

It has been argued [T. Rudolph and B.C. Sanders, Phys. Rev. Lett. {\bf 87}, 077903 (2001)] that continuous-variable quantum teleportation at optical frequencies has not been achieved because the source used (a laser) was not `truly coherent'. Van Enk, and Fuchs [Phys. Rev. Lett, {\bf 88}, 027902 (2002)], while arguing against Rudolph and Sanders, also accept that an `absolute phase' is achievable, even if it has not been achieved yet. I will argue to the contrary that `true coherence' or `absolute phase' is always illusory, as the concept of absolute time (at least for frequencies beyond direct human experience) is meaningless. All we can ever do is to use an agreed time standard. In this context, a laser beam is fundamentally as good a `clock' as any other. I explain in detail why this claim is true, and defend my argument against various objections. In the process I discuss super-selection rules, quantum channels, and the ultimate limits to the performance of a laser as a clock. For this last topic I use some earlier work by myself [Phys. Rev. A {\bf 60}, 4083 (1999)] and Berry and myself [Phys. Rev. A {\bf 65}, 043803 (2002)] to show that a Heisenberg-limited laser with a mean photon number $\mu$ can synchronize $M$ independent clocks each with a mean-square error of $\sqrt{M}/4\mu$ radians$^2$.

Topological phase of optical vortices in few-mode fibers

It has been found that as they propagate, the natural optical vortices of a few-mode parabolic fiber acquire a topological phase in addition to the dynamic phase. The magnitude of this phase is numerically equal to the polarization correction to the propagation constant of the CV and IV vortices. An analysis revealed that this phase is a new type of optical manifestation of the topological Berry phase. The already known Pancharatnam and Rytov-Vladimirski $$\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l}$$ . phases are associated with changes in the magnitude and direction of the angular momentum flow of the wave. In the fields of natural vortices of a few-mode fiber all the explicit parameters of the wave remain unchanged during propagation. However, the direction of the momentum density vector of the vortex undergoes cyclic variations along the trajectory of the energy flow line. These cyclic variations of the implicit vortex parameter are responsible for the new type of topological phase. Unlike the study made by van Enk (Ref. 6), where the topological phase was only related to the angular momentum for the lowest-order Gaussian beams (l=±1), this topological phase describes guided vortices with any values l of the topological charge. The results can be used to estimate the stability of CV and IV vortices relative to external perturbing influences on the optical fiber.

The electric dipole approximation and the calculation of free - free transition matrix elements in multiphoton processes

In view of the arguments put forward by van Enk et al, we discuss aspects of the theory of atom - laser field interactions as they relate to the calculation of properties for which free - free transitions play a significant role. Our conclusion is that: (i) according to the standard definition of the electric dipole approximation, which is what has been employed until now in all non-perturbative calculations of multiphoton processes, the on-energy shell singularity for the length and velocity gauges is real when the one-electron continuum is represented rigorously by energy-normalized scattering functions. On the other hand, the acceleration gauge does not give rise to this singularity. (ii) When the full coupling operator rather than is used, the singularity persists for the electric dipole as well as for the higher multipoles. (iii) The use of box-normalized basis sets only leads to a model space whereby even repeated (and computationally expensive) calculations with increasing box size lack intrinsic rigour and the certainty that convergence implies accuracy.

One photon and macroscopic B cyclic equations: Reply to van Enk

The B cyclics of electrodynamics, which relate transverse and longitudinal fields in vacuo, are one photon relations which are also valid on a macroscopic scale. In the same way, the Maxwell equations in the received view were originally phenomenological relations between electric and magnetic fields, but, in the received view are also written down for one photon. Point by point replies to van Enk are given.