Permanent Memory Research Articles

Memory and Development of Textures of Polydomain Nematic Elastomers

AbstractThe texture development during the polydomain‐to‐monodomain (PM) transition in nematic elastomers with isotropic (I‐PNE) or nematic genesis (N‐PNE) is studied. I‐PNE exhibits a uniform polydomain texture, and the PM transition occurs at a constant small force, resulting in a uniform monodomain texture. N‐PNE exhibits the Schlieren texture that is composed of large domains with many defects and is similar to that before cross‐linking. N‐PNE requires much more mechanical work than I‐PNE for the PM transition. In N‐PNE, remnants of the initial texture are still observed in the stretched aligned state, while the initial texture and dimensions are completely restored when the imposed strain is removed. The permanent memory of the initial texture becomes a robust constraint to the rotation of the local directors.

Polymorph stabilization in processed acetaminophen powders

A novel approach has been developed to stabilize the metastable form II of acetaminophen (APAP) prepared from the melt of micronized and nano-silica coated APAP I. It is suggested that stabilization of form II APAP occurs by pinning via van der Waals-type interactions on low energy defects created by micronization and impinging particles during dry coating in form I APAP, heating to the melt phase, and cooling. The defects are likely to persist into the near-molten isotropic phase due to a permanent memory effect similar to that previously observed in silica-liquid crystal composites and re-crystallize together with form II APAP. Raman spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and conventional as well as intrinsic dissolution have been used to characterize the stabilized APAP II obtained. Raman measurements up to 18 months and PXRD data for micronized form II APAP show no indication of APAP I formation. Aged samples of dry-coated APAP II however display Raman features indicative of APAP I within 5 months. PXRD and SEM techniques also detected small fractions of APAP I in dry-coated APAP II. Both micronized APAP II and dry-coated APAP II give rise to a time-dependent background scattering superimposed on the Raman spectra which increases in integrated intensity with time, saturates at 180 and 90 days, respectively, and then decreases in intensity with further aging. The time-dependent scattering background occurs in the stabilized form II APAP samples only after cooling from the melt and is more intense in micronized APAP II compared to dry-coated APAP II. It is assigned to disorder associated with slowly diffusing defects created by micronization and dry coating with impinging nano-silica particles in form I APAP. Intrinsic dissolution profiles for the stabilized APAP II samples showed measureable increases, particularly for micronized APAP II.

A Post-National Spanish Imaginary. A Case-Study: Pan's Labyrinth

The acclaimed film Pan's Labyrinth (El laberinto del fauno, 2006, directed by Mexican filmmaker Guillermo del Toro) portrays the repression of democratic resistance (the maquis) during the years that followed Franco's victory over the Spanish Republic in 1939. The film focuses on a sadistic military officer and his determination to kill and torture people, and on a child, his stepdaughter, who rebels and escapes to a world of fantasy. In the following pages I argue that the narrative of Pan's Labyrinth presents a reconsideration of State-sponsored Fascist repression in terms of a male-dominated order. I argue that this portrayal implies a displacement of the political nature of totalitarian violence from questions regarding the nation-State to the sphere of a cultural region. I further argue, then, that Pan's Labyrinth belongs to what Paul Julian Smith has called a Trans-Atlantic traffic. Cross-national production companies, film-makers and actors are creating a flux of films that do not identify strictly as a national product, but rather a circuit of production, exchange and distribution (Smith). The displacement from the nation permits us to raise important considerations regarding the current status of the notion of Spanish as a brand in the marketing of cultural issues. ON FASCIST VIOLENCE. THE FATHER, THE LAW OF DEATH--THE PATRIARCHAL MEMORY The major conflict within the narrative of the film is not (or is not exclusively) between Franco's repressive forces and the anti-Fascist resistance, but above all between a Fascist officer, Captain Vidal, and his stepdaughter, Ofelia. The child's father died at the start of the war, and her mother has now married Vidal in order to have a better living amid the miseries of scarcity and poverty in post-war Spain. The child shows no affection to her stepfather; on the contrary she rejects him from the first moment. Her disposition to fantasy is further strengthened when she arrives with her mother to the small town where Vidal is leading the hunting and killing of resistance fighters. Indeed, it becomes a means of survival in the hostile home. While her mother prepares herself in ill conditions to deliver Vidal's baby, Ofelia creates a fairy-tale story in which she is the heroine of a struggle that obviously parallels the simultaneous story of the democratic fighters against Vidal and Franco's repression. Her fantasy world is intended to substitute and at the same time isolate the atrocities of the evil and repression that she sees around her; her fairy-tale becomes a symbolic transgression of a social order dominated by Fascism (Tsuei). Fascism is certainly evoked in the film as a military power allied with an oligarchy with the goal of preserving their economic interests, which seem to be challenged by the popular classes. However, the narrative of the film emphasizes the sadistic characterization of Vidal to such a degree that this psychological perspective overcomes the representation of Fascist violence. The officer is portrayed with an essential disposition toward murder and the inflicting of pain. Indeed, Vidal carries out the killing of civilians and the persecution of anti-fascist fighters with a sort of personal passion that is above and beyond what his subordinated officers are willing to do. At the same time, the film portrays this evil officer as struggling with himself and with the memory of his own father. Vidal carries with him at all times his father's watch, as a permanent memory of the exact time of his death in battle. His mystification of the love for his father in terms of an exaltation of death and war certainly points to a characterization of Fascism as a culture of death and of a masculine veneration of war. The emphasis, however, on depicting obsessive traits rather than an ideological conviction for the establishment of a Fascist state, permits us to see Vidal as a pathological individual and, then, to focus on the characterization of political repression in terms of emotions and a dynamics of love and hate within a familial space under a patriarchal power. …

Immune based fuzzy agent plays checkers game

One of the advantages of immune based approaches is the usage of permanent memory cells. These memory cells cause to omit the process of learning for any played strategy and consequently increasing the speed of decision making process. In the proposed method of this article, memory cells represent actions that have the best local payoff for that current state of the game and are generated simultaneously by learning process. These cells help the decision making system to decide better, considering the previous and future state of the game. The decision making system that is used in this method is based on a Mamdani fuzzy inference engine (FIS). The FIS proposes a best action for the current state of the board by extracting memory cells’ data. Experiments show that the immune based fuzzy agent which is introduced here has better results among other previous methods. This new method can show proper resistance when confronting a player that uses complete game tree remarkably. Also this method is capable of suggesting an action for each state of the game by generating less number of generations in comparison with other evolutionary based methods.

Unilateral lesion of dorsal hippocampus in adult rats impairs contralateral long-term potentiation in vivo and spatial memory in the early postoperative phase

It is well documented that bilateral hippocampal lesions or unilateral hippocampal lesion at birth causes impairment of contralateral LTP and long-term memory. However, effects of unilateral hippocampal lesion in adults on contralateral in vivo LTP and memory are not clear. We here examined the influence of unilateral electrolytic dorsal hippocampal lesion in adult rats on contralateral LTP in vivo and spatial memory during different postoperative phases. We found that acute unilateral hippocampal lesion had no effect on contralateral LTP. However, contralateral LTP was impaired at 1 week after lesion, and was restored to the control level at postoperative week 4. Similarly, spatial memory was also impaired at postoperative week 1, and was restored at postoperative week 4. In addition, the rats at postoperative week 1 showed stronger spatial exploratory behavior in a novel open-field environment. The sham operation had no effects on contralateral LTP, spatial memory and exploration at either postoperative week 1 or week 4. These results suggest that unilateral dorsal hippocampal lesion in adult rats causes transient contralateral LTP impairment and spatial memory deficit.

Hippocampal function is not required for the precision of remote place memory

BackgroundDuring permanent memory formation, recall of acquired place memories initially depends on the hippocampus and eventually become hippocampus-independent with time. It has been suggested that the quality of original place memories also transforms from a precise form to a less precise form with similar time course. The question arises of whether the quality of original place memories is determined by brain regions on which the memory depends.ResultsTo directly test this idea, we introduced a new procedure: a non-associative place recognition memory test in mice. Combined with genetic and pharmacological approaches, our analyses revealed that place memory is precisely maintained for 28 days, although the recall of place memory shifts from hippocampus-dependent to hippocampus-independent with time. Moreover, the inactivation of the hippocampal function does not inhibit the precision of remote place memory.ConclusionThese results indicate that the quality of place memories is not determined by brain regions on which the memory depends.

Preparation and measurement methods for studying nanoparticle aggregate surface chemistry

Despite best efforts at controlling nanoparticle (NP) surface chemistries, the environment surrounding nanomaterials is always changing and can impart a permanent chemical memory. We present a set of preparation and measurement methods to be used as the foundation for studying the surface chemical memory of engineered NP aggregates. We attempt to bridge the gap between controlled lab studies and real-world NP samples, specifically TiO(2), by using well-characterized and consistently synthesized NPs, controllably producing NP aggregates with precision drop-on-demand inkjet printing for subsequent chemical measurements, monitoring the physical morphology of the NP aggregate depositions with scanning electron microscopy (SEM), acquiring "surface-to-bulk" mass spectra of the NP aggregate surfaces with time-of-flight secondary ion mass spectrometry (ToF-SIMS), and developing a data analysis scheme to interpret chemical signatures more accurately from thousands of data files. We present differences in mass spectral peak ratios for bare TiO(2) NPs compared to NPs mixed separately with natural organic matter (NOM) or pond water. The results suggest that subtle changes in the local environment can alter the surface chemistry of TiO(2) NPs, as monitored by Ti(+)/TiO(+) and Ti(+)/C(3)H(5)(+) peak ratios. The subtle changes in the absolute surface chemistry of NP aggregates vs. that of the subsurface are explored. It is envisioned that the methods developed herein can be adapted for monitoring the surface chemistries of a variety of engineered NPs obtained from diverse natural environments.

Electrically permanent memory characteristics of an ionic conjugated polymer

In this work, an ionic conjugated polymer with propargyl side groups (poly(2-ethynylpyridinum bromide); PEP-P) was synthesized. High-quality thin films with smooth surfaces were prepared from this polymer on silicon substrates and metal electrodes, via a conventional, simple solution-coating and drying process. Synchrotron X-ray scattering analysis showed that the polymer in the nanoscale thin films was amorphous, but was somewhat preferentially oriented in the film plane, rather than randomly oriented. Using synchrotron X-ray reflectivity analysis, the electron densities and interfaces between the polymer film layers and the silicon substrate and metal electrodes were examined in detail. To our knowledge, PEP-P is the first ionic conjugated polymer to be shown to exhibit electrically nonvolatile memory behavior. The polymer in the nanoscale thin films showed excellent write-once-read-many-times (WORM) memory characteristics, without any polarity. The switching-ON voltage was lower than 1.5 V. WORM memory devices based on PEP-P were highly stable, even under ambient air conditions. PEP-P therefore has great potential as a candidate material for the low-cost mass production of high-performance, programmable unipolar WORM memory devices with very low power consumption.

Excitation Waves Returning to the Hippocampus via the Entorhinal Cortex Can Reactivate Populations of “Trained” Field CA1 Neurons during Deep Sleep

It is suggested that information on new stimuli from the neocortex is transmitted to the hippocampus, where temporal traces persist in the form of mosaics of modified synapses. During sleep, populations of neurons storing these traces are reactivated and return the information required for consolidation of a permanent memory trace to the neocortex. A possible mechanism for the reactivation of “trained” hippocampal neurons during memory consolidation consists of the reverberation of excitation in the neuron circuits linking the hippocampus and entorhinal cortex. Our studies in rats included recording of responses in hippocampal field CA1 to stimulation of Schaffer collaterals with potentiated synapses during waking and sleep. During deep sleep, discharges of field CA1 neurons were followed by waves of excitation which passed through the entorhinal cortex and reached the hippocampus and dentate gyrus via fibers of the perforant path, evoking neuron discharges in the latter. Repeated neuron discharges in field CA1 occurred on interaction of the early excitation wave returning directly via perforant path fibers and the late wave returning via Schaffer collaterals, not via the trisynaptic path via the dentate gyrus and hippocampal field CA3 but probably via field CA2.

Memory effect in composites of liquid crystal and silica aerosil

Aerosil silica nanoparticles dispersed in a liquid crystal (LC) possess the interesting property of keeping memory of an electric- or magnetic-field-induced orientation. Two types of memory have been identified: thermally erasable memory arising from the pinning of defect lines versus a "permanent" memory where the orientation persists even after thermal cycling the samples up to the isotropic phase. To address the source of the latter type of memory, solid-state nuclear magnetic resonance spectroscopy and conventional x-ray diffraction (XRD) were first combined to characterize the LC orientational order as a function of multiple in-field temperature cycles. Microbeam XRD was then performed on aligned gels of different concentrations to gain knowledge of the structural properties at the origin of the memory effect. No detectable anisotropy of the gel or significant breaking of silica strands with heating ruled out the formation of an anisotropic silica network as the source of the permanent memory as previously proposed. Instead, support for a role of the surface memory effect, well known for planar substrates, in stabilizing the permanent memory was deduced from "training" of the composites, that is, optimizing the orientational order through the thermal in-field cycling. The ability to train the composites is inversely proportional to the strength of the random-field disorder. The portion of thermally erasable memory also decreases as the silica density increases. We propose that the permanent memory originates from the surface memory effect operating at points of intersection in the silica network. These areas, where the LC is strongly confined with conflicted surface interactions, are trained to achieve an optimized orientation and subsequently act as sites from which the LC orientational order regrows after zero-field thermal cycling up to the isotropic phase.

P‐157: Twisted‐nematic LCD Switchable between Dynamic and Memory Modes

AbstractWe propose a reflective TN device switchable between the dynamic and memory modes. It can be operated in either the dynamic or memory mode depending on the application. The proposed mode uses the selective switching among the −90° twist, +90° twist, and vertical alignment states. Operation of the proposed device in the dynamic mode is same as the conventional TN cell. In the memory mode, the permanent memory characteristics of the −90° and +90° twist states can be obtained.

Memory effects and carrier transport mechanisms of write-once- read-many-times memory devices fabricated using poly(3-hexylthiophene) molecules embedded in a polymethylmethacrylate layer on a flexible substrate

The memory effects and the carrier transport mechanisms of write-once-read-many-times (WORM) memory devices fabricated using poly(3-hexylthiophene) (P3HT) molecules embedded in a polymethylmethacrylate (PMMA) polymer layer on a flexible substrate were investigated. Current-voltage (I-V) curves at 300 K for Al/P3HT:PMMA/indium-tin-oxide WORM device showed a permanent memory behavior with an ON/OFF ratio of 104. The estimated retention time of the ON state of the WORM device was more than 10 years. The carrier transport mechanisms of the WORM memory devices are described using several models to fit the experimental I-V data.

반사형 쌍안정 카이랄 스플레이 네마틱 액정표시소자

Bistable chiral splay nematic liquid crystal display (BCSN LCD) is a memory type liquid crystal display using splay and twist states as two stable states. When the cell thickness to pitch (d/p) ratio is 0.25, splay and twist states have permanent memory time. However, when the transition from twist state to splay state is caused by a fringe field, pixel regions show that the splay state is not perfect, but rather includes a contribution from the twist state. In this paper, we propose a reflective BCSN LCD using twist state in which the two stable states do not coexist. The fabricated reflective BCSN LC cell shows a high contrast ratio of over 30:1 and response times of 950 ms and 450 ms in vertical and fringe field switching, respectively. The proposed cell also shows wide viewing angle characteristics of in left- and right directions.

Transinguinal preperitoneal groin hernia repair using a preperitoneal mesh preformed with a permanent memory ring: a good alternative to Lichtenstein’s technique

PurposeThe transinguinal preperitoneal (TIPP) technique uses a preperitoneal mesh preformed with a permanent memory ring, which greatly facilitates application of Rives’ technique. The purpose of this retrospective study was to evaluate our primary results by systematic clinical and ultrasound evaluations more than 1 year after surgery.MethodsThis unicentric study included all consecutive adult patients treated with surgery for a groin hernia by the same surgeon using the same technique between December 2006 and December 2008. Any patient who participated in this study had both a systematic clinical and ultrasound control between 6 months and 3 years after surgery.ResultsIn this study, we performed 145 hernia repairs. There was no infection of the mesh and no clinical recurrence; additionally there was an ultrasound recurrence (n = 3) in 2% of asymptomatic patients and chronic pain in 4.8% of patients who did not require the consumption of systematic painkillers and are not limited in their activities.ConclusionsIt is feasible to correct a groin hernia using a preperitoneal preformed mesh with a permanent memory ring. Our study confirms the positive results of Pélissier and colleagues (Pélissier and Ngo, Ann Chir 131:590–594, 2006; Pélissier et al. J Chir 144(4):5S35–5S40, 2007; Pélissier et al. Hernia 11:229–234, 2007; Pélissier et al. Hernia 12:51–56, 2007) and Berrevoet et al. (Hernia 13:243–249, 2009; Langenbeck’s Arch Surg 395:557–562, 2010) and is the first study to use a systematic clinical and ultrasound control more than 1 year after surgery. This technique has a low rate of complications, including ultrasound recurrence in 2% of patients without any clinical recurrence and chronic pain in 4.8% of patients who did not require the consumption of systematic painkillers and are not limited in their activities. This technique consisted of the placement of a patch in the preperitoneal space, which combines the benefits of the anterior approach (i.e., easy technique, short learning curve, low cost) and the preperitoneal placement of the mesh (less recurrence, less pain). This procedure is a good alternative to Lichtenstein’s technique.

On Memory, General Anesthesia, and Sleep

University of Iowa, Iowa City. mohamed-ghoneim@uiowa.eduI read with great interest the erudite editorial that accompanied the article by Pham et al. 2by my colleague, Professor Lichtor.1In their article, Pham et al. 2found no evidence of implicit memory formation during anesthesia in children.Without providing clear and concise answers, Lichtor1asks the following question: Is memory formation during anesthesia similar to what goes on during sleep? General anesthesia abolishes explicit or conscious memory except in the rare cases of awareness during anesthesia.3The evidence for memory formation beyond unconsciousness is controversial. It may occur only during light anesthesia, short of consciousness.4When it occurs, there is only evidence of perceptual, but not conceptual, priming.5As for sleep, Lichtor1notes there is evidence that it contributes to the consolidation of some types of explicit memory. There are also some reports that it enhances the learning of motor and perceptual skills.6Lichtor1asks another question: Would patients have better postoperative control of pain and anxiety if therapeutic instructions are given both preoperatively and intraoperatively? My answer has to be negative. For patients to comprehend instructions during anesthesia, there must be conceptual priming, which does not occur during anesthesia—except at its lightest levels (e.g. , nitrous oxide, opioids, and muscle relaxants),7where conscious encoding of stimuli is still possible.5After a 1988 report that claimed improved recovery and reduced hospital stay for patients after surgery,8nearly all credible and controlled studies failed to replicate this finding or other beneficial findings relating to postsurgical analgesia, nausea and vomiting, cessation of smoking, and so on.9The suggestion by Lichtor1that anesthesia might be similar to sleep processes that facilitate memory consolidation cannot be true because anesthetics abolish memory by suppression of consolidation.10–12Finally, although Hermann Ebbinghaus introduced many important ideas and methods for memory research (with himself as the sole subject) in the late 19th century, I would attribute the introduction of implicit or nonconscious forms of human memory to the literature at a much later date. The first suggestion that conscious or implicit memory exists was in 1957, when Scoville and Milner reported the case of patient H.M., who after surgery for epilepsy was unable to convert a new short-term memory into a permanent long-term memory.13He could, however, learn new motor skills without any awareness that he had ever before performed the tasks. Research into implicit memory exploded in the early 1980s.13The above comments should not, however, obscure my agreement with my colleague's outstanding statement that, “although there are some similarities between anesthesia and sleep, general anesthesia is not really the same as sleep.”University of Iowa, Iowa City. mohamed-ghoneim@uiowa.edu

Gibt es eine neuropsychologische Rückfallprävention bei Alkoholabhängigen?

Advances in neurosciences have pointed to the handicaps in autonomy of alcohol patients in the moment of relapse. Research has lead to the concept of a permanent addiction memory which is characterized by a momentary restraint of rational self control by automatic information processing bias and appetence reactions to alcohol triggers in high risk situations. Because alcohol patients are not necessarily aware of these automatic processes, the latter can not be overcome by traditional methods of cognitive-behavioral relapse prevention. The paper will discuss to what extent a neuropsychological perspective is helpful to improve assessment tools and specific interventions for relapse prevention in alcoholic patients.

Examples of Scaffolding and Chunking in Online and Blended Learning Environments

Scaffolding and chunking are instructional strategies designed to support the relationship of new information to prior knowledge in manageable sizes for the learner’s working memory. This paper defines scaffolding and chunking instructional strategies as they relate to information processing, describes how to determine and when to use scaffolding and chunking, and provides examples of when scaffolding and chunking have been used effectively in online and blended learning environments.Scaffolding is based within Vygotsky’s Social Development Theory that proposes that learning occurs through participation in socially or culturally embedded experiences. A competent instructor presents information that activates the learner’s zone of proximal development just above the learner’s current skills level. Online and blended materials can include interactive strategies to help the learner elaborate on their prior knowledge. The interactive bridges are built within the educational materials or provided through interactions with other learners or the instructor.Chunking is the process of taking individual units of information and grouping them into larger units. Working memory functions optimally with no more than five to nine pieces of information. By chunking information in larger blocks, the information becomes easier to move from working memory to permanent memory, be linked to prior knowledge, and be recalled at a later time.The placement and use of instructional strategies is based upon where the learner demonstrates difficulty in relating the materials to prior knowledge or has difficulty recalling the information. Hierarchical analysis of the instructional materials, learner analysis, and evaluation of learner performance are techniques used to place the instructional strategies most effectively and efficiently for a proper balance of support and challenge to motivate the learner.

Spatial phase modulation from permanent memory in doped glass

Diffraction rings are observed from photoinduced permanent memory of doped glass. The permanent memory is created by the high-intensity picosecond laser beam. A 1 mm spot size of laser beam creates spatially variable refractive index memory, which appears as a void located inside the glass. When a probe laser beam passes through the memory region, the diffraction rings arisen from spatial phase modulation of the transverse phase of the input beam are created. Agreement between the observed and calculated beam pattern using Kirchhoff's diffraction integral is satisfactory.

Return of Excitatory Waves from Field CA1 to the Hippocampal Formation Is Facilitated after Tetanization of Schäffer Collaterals during Sleep

Current concepts hold that during learning in waking animals, new information is transmitted from the neocortex to the hippocampus, where it leaves a temporary trace in the form of a mosaic of modified synapses. During sleep, reactivation of the neuron population initially activated by the new stimulus has the result that this information is returned to the neocortex, ensuring consolidation of a permanent memory trace. Exchange of information between the neocortex and hippocampal formation is mediated mainly by the entorhinal cortex, whose internal connections, in principle, allow "messages" from the output of the hippocampal formation to return to its inputs. Our experiments in awake and sleeping rabbits demonstrated that waves of excitation can return to hippocampal field CA1 and the dentate gyrus via fibers of the perforant path, these waves having initially entered field CA1 via potentiated synapses of Schäffer collaterals; during sleep, re-entrant waves of excitation reach a maximum and have a high probability of evoking discharges of dentate gyrus neurons. Thus, the new stimulus, potentiating synaptic connections in the hippocampus and, probably, the entorhinal cortex during waking, create conditions for reactivation of the corresponding hippocampal neuron populations during sleep by waves of excitation returning via the entorhinal cortex.

Using the education strategy with directing questions in the teaching period sample lesson: one dimensional motion

It is believed that using the education strategy with directing questions in the teaching period can increase the students’ meaningful learning level in the physics education. The productivity of this period is related to the quality of the questions be prepared and the relation between student and student, student and the tutor. The teaching period is composed of certain phases. These phases are preparation, presentation, application and evaluation. Any question in every phase has an important role in this teaching period. These questions prepared for the subject's being understood better by the students must be prepared in a way that covers concrete pedagogical aims which comprise upper cognitive aims. As a conclusion, realizing active learning on students and transporting the information to permanent memory is only related to the strategy which will be used by the tutor.