[Application of "patient and public involvement" in acupuncture clinical research]

In order to explore the application of "patient and public involvement" (PPI) in acupuncture clinical research, the connotation, reporting standards and research status of PPI at home and abroad are collated, and the key problems of PPI encountered in acupuncture clinical research are deeply considered and summarized. It is suggested that the short-form checklist of the Guidance for Reporting Involvement of Patients and the Public (GRIPP) of the 2nd edition should be applied to acupuncture clinical research. PPI provides a new perspective for acupuncture clinical research. It is beneficial for each stage of research, contributes to the improvement of acupuncture medical service mode and increases the success rate and cost-effectiveness of research so that the innovation and development of acupuncture science can be promoted.

Acupuncture for chronic sciatica: protocol for a multicenter randomised controlled trial

BACKGROUND

Chronic Sciatica is a disabling condition causing considerable medical, social and financial implications. Currently, there is no recognised long-term effective treatment to alleviate sciatica. Acupuncture has been widely used for treating chronic pains with persistent analgesic effects. We aim to evaluate the efficacy and safety of acupuncture for chronic sciatica with follow-up in 52 weeks.

METHODS AND ANALYSIS

This is a multicenter randomised sham-controlled trial. A total of 216 patients with chronic sciatica will be enrolled and randomly assigned to the acupuncture or sham acupuncture group. There will be 10 treatment sessions applied in 4 weeks with frequency decreased over time. Patients will complete follow-ups during 52 weeks. The primary outcomes are changes in leg pain intensity and disability from baseline to week 4. Secondary outcomes include back pain intensity, frequency and bothersomeness, quality of life, and global perceived effect. Adverse events will be recorded in detail.

ETHICS AND DISSEMINATION

Ethical approval of this trial was granted from the ethics committee of Beijing University of Chinese Medicine and all study centres (No. 2020BZYLL0803). Written informed consent will be obtained from enrolled patients. Trial results will be disseminated in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ChiCTR2100044585 (Chinese Clinical Trial Registry, http://www.chictr.org.cn, registered on 24 March 2021); preresults.

Is acupuncture effective for knee osteoarthritis? A protocol for a systematic review and meta-analysis

INTRODUCTION

Knee osteoarthritis (KOA) is one of the leading causes of disability. The effectiveness of acupuncture for treating KOA remains controversial. This protocol describes the method of a systematic review and meta-analysis evaluating the effectiveness and safety of acupuncture for treating KOA.

METHODS AND ANALYSIS

Four English databases (PubMed, Embase, Cochrane Library databases and Web of Science) and four Chinese databases (China National Knowledge Infrastructure, Chinese Biomedical Literature Database, VIP Database for Chinese Technical Periodicals, and Wanfang) will be searched from the database inception to 1 September 2021. All randomised controlled trials related to acupuncture for KOA will be included. Extracted data will include publication details, basic information, demographic data, intervention details and patient outcomes. The primary outcome will be pain intensity. Risk of bias will be assessed using the Cochrane Collaboration's tool for assessing risk of bias. Article selection, data extraction and risk of bias assessment will be performed in duplicate by two independent reviewers. If the meta-analysis is precluded, we will conduct a descriptive synthesis using a best-evidence synthesis approach. The strength of recommendations and quality of evidence will be assessed using the Grading of Recommendations Assessment Development and Evaluation working group methodology.

ETHICS AND DISSEMINATION

Ethics approval is not required because individual patient data are not included. This protocol was registered in the international Prospective Register of Systematic Reviews on 25 February 2021. The systematic review and meta-analysis will be submitted for publication in a peer-reviewed journal. The findings will also be disseminated through conference presentations.

TRIAL REGISTRATION NUMBER

CRD42021232177.

Evaluating the efficacy and safety of electro-acupuncture in patients with antipsychotic-related constipation: protocol for a randomized controlled trial

Background

Constipation is known as a common adverse effect of antipsychotics. Advice for its management remains inadequate. This study is designed to investigate the efficacy and safety of electro-acupuncture (EA) for antipsychotic-related constipation.

Methods

This is a single-centric, parallel-group, randomized controlled trial with blinded participants, outcome assessor, and statistician. One hundred twelve participants will be randomly assigned into the EA group or sham acupuncture (SA) group in a 1:1 ratio. The study will last for 22 weeks for each participant, including a 2-week baseline assessment period, an 8-week treatment period, and a follow-up for 12 weeks. The primary outcome is the change of mean weekly complete spontaneous bowel movements (CSBMs) during weeks 1 to 8 from baseline. Secondary outcomes include the change from baseline of mean weekly CSBMs during the follow-up period, mean weekly spontaneous bowel movements (SBMs), overall CSBM response rate, scores on Bristol Stool Form Scale (BSFS), straining level, Patient Assessment of Constipation Symptoms (PAC-SYM), Patient Assessment of Constipation Quality of life questionnaire (PAC-QOL), and Brief Psychiatric Rating Scale (BPRS). Adverse events and medicine use will be recorded as well.

Discussion

The study is designed based on a rigorous methodology to evaluate the efficacy and safety of EA for antipsychotic-related constipation. The finding will be published in peer-reviewed journals as reliable evidence.

Trial registration

ClinicalTrials.gov ChiCTR2000032582. Registered May 3, 2020, with the Chinese Clinical Trial Registry.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05732-5.

Acupuncture for the treatment of diarrheal-predominant irritable bowel syndrome: study protocol for a pilot randomized controlled trial

BACKGROUND

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal diseases. Although acupuncture has become a common alternative therapy for IBS, there is insufficient evidence for its effectiveness. This study was designed to assess the efficacy and feasibility of acupuncture in the treatment of IBS.

METHODS/DESIGN

This is a multicenter randomized controlled clinical trial. According to the ratio of 1:1:1, 90 patients with irritable bowel syndrome will be randomly divided into specific acupoints (SA) group, non-specific acupoints (NSA) group, and non-acupoints (NA) group. All patients will be treated with acupuncture 12 times within 4 weeks and followed up for 8 weeks. The primary outcome is the response rate, the percentage of patients whose average value of worst abdominal pain is 30% better and the days of loose stool is 50% less than the baseline, at week 4 after randomization. The secondary outcomes include the response rates at other time points, IBS Symptom Severity Scale (IBS-SSS), Patient Health Questionnaire-9 depression scale (PHQ-9), IBS-Quality of Life scale (IBS-QOL), IBS Adequate Relief (IBS-AR), Abdominal Pain Score, Abdominal Bloating Score, Bristol Stool Score (BBS), blinding assessment, and credibility evaluation. Adverse events will be monitored and recorded during the trial.

TRIAL REGISTRATION

Chictr.org.cn ChiCTR2000030670. Registered on 9 March 2020.

Electroacupuncture ameliorates intestinal inflammation by activating α7nAChR-mediated JAK2/STAT3 signaling pathway in postoperative ileus

Inflammatory cytokines produced by muscularis macrophages largely contribute to the pathological signs of postoperative ileus (POI). Electroacupuncture (EA) can suppress inflammation, mainly or partly via activation of vagal efferent. The goal of this study was to investigate the mechanisms by which EA stimulation at an hindlimb region ameliorates inflammation in POI.

Methods: Intestinal motility and inflammation were examined after 24 h after intestinal manipulation (IM)-induced POI in mice. Local immune response in the intestinal muscularis, expression of macrophages, α7 nicotinic acetylcholine receptor (α7nAChR), Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) were determined by flow cytometry, Western Blot, qPCR and immunofluorescence. The effects of α7nAChR antagonists (methyllycaconitine and α-bungarotoxin) and JAK2/STAT3 inhibitors (AG490 and WP1066) were also administered in a subset of mice prior to EA. In the parasympathetic pathways, intestinal motility and inflammation were determined after cervical vagotomy and sub-diaphragmatic vagotomy. The expression of gamma absorptiometry aminobutyric acid (GABA_A) receptor in dorsal motor nucleus of vagal (DMV) cholinergic neurons was assessed by immunofluorescence and the response to DMV microinjection of bicuculine (antagonist of GABA_A receptor) or muscimol (agonist of GABA_A receptor) were assessed.

Results: EA suppressed intestinal inflammation and promoted gastrointestinal motility. Mechanistically, EA activated the α7nAChR-mediated JAK2/STAT3 signaling pathway in macrophages which reduced the production of inflammatory cytokines. Furthermore, we also demonstrated that hindlimb region stimulation drove vagal efferent output by inhibiting the expression of GABA_A receptor in DMV to ameliorate inflammation.

Conclusions: The present study revealed that EA of hindlimb regions inhibited the expression of GABA_A receptor in DMV neurons, whose excited vagal nerve, in turn suppressed IM-induced inflammation via activation of α7nAChR-mediated JAK2/STAT3 signaling pathway.

Acupuncture for Psychological Disorders Caused by Chronic Pain: A Review and Future Directions

Accumulating evidence supports an association between chronic pain and psychological disorders, a connection that seems to be bidirectional. Treating both the pain and psychological conditions together is essential for effective treatment outcomes. Acupuncture is a somatosensory-guided mind-body therapy that can tackle the multidimensional nature of pain with fewer or no serious adverse effects. In this review, we discuss the use of acupuncture in some conditions with a high incidence of psychological disorders caused by chronic pain: headache, musculoskeletal pain, low back pain, and cancer pain, focusing on the effect and potential mechanisms of acupuncture. Overall clinical studies indicated that acupuncture might effectively contribute to management of psychological disorders caused by chronic pain. Mechanistic studies showed that acupuncture significantly alleviated such psychological disorders by regulating the activity of amygdala and insula, and regulating functional connectivity of insular and limbic regions/medial prefrontal cortex in humans and the corresponding animal models. In addition, 5-HT in the dorsal raphe nucleus, opioid receptors in the cingulate cortex, and plasma met-enkephalin are involved in acupuncture relief of pain and psychological symptoms. Substantial evidences from animal and human research support a beneficial effect of acupuncture in psychological disorders caused by chronic pain.

The Management of Sciatica by Acupuncture: An Expert Consensus Using the Improved Delphi Survey

Objective

Acupuncture therapy is an effective non-drug therapy for sciatica, but it has not yet formed an effective treatment strategy and recommendations. Our objective was to establish an expert consensus on acupuncture treatment of sciatica for clinical guidance based on the improved Delphi survey.

Methods

A group of 80 clinical specialists was invited to participate in two rounds of semi-open clinical issue investigation. At the same time, the PubMed, Embase, and Cochrane Library databases were searched for systematic reviews on acupuncture treatment of sciatica, and the quality of evidence was evaluated. Then the three-round Delphi survey was undertaken with 30 experts based on the clinical issue investigation and systematic reviews.

Results

In round 1 of the Delphi survey, the experts evaluated 17 items identified from the results of the clinical investigation and literature review. The criterion for achieving consensus was a threshold of 80% agreement. After the three-round Delphi survey, 16 items (94.12%) achieved consensus, including 5 domains: the principle of acupuncture treatment for sciatica; the “dose” of acupuncture; the clinical effects of acupuncture; the adverse effects, and others.

Conclusion

This Delphi survey achieved an expert consensus on key items in the management of sciatica for acupuncture, which provides the current opinions in China. We trust that these treatment recommendations may facilitate their implementation in the future.

Acupuncture for persistent atrial fibrillation after catheter ablation: study protocol for a pilot randomized controlled trial

Background

Atrial fibrillation (AF) is a common arrhythmia, which is closely related to cardiovascular morbidity and mortality. Although acupuncture is used in the treatment of AF, the evidence is insufficient. The objective of this pilot trial is to evaluate the feasibility, preliminary efficacy, and safety of acupuncture in reducing AF burden for persistent AF after catheter ablation (CA).

Methods and design

This will be a multi-center, 3-arm, pilot randomized controlled trial in China. Sixty patients in total will be randomly assigned to the specific acupoints group, the non-specific acupoints group, or the non-acupoints group in a 1:1:1 ratio. The whole study period is 6 months, including a 3-month treatment period and a 3-month follow-up period. All patients will receive 18 sessions of acupuncture over 12 weeks after CA and appropriate post-ablation routine treatment. The primary outcome is AF burden at 6 months after CA measured by electrocardiography patch that can carry out a 7-day continuous ambulatory electrocardiographic monitoring. The secondary outcomes include AF burden at 3  months after CA, recurrence of AF, quality of life, etc. The adverse events will also be recorded.

Discussion

This pilot study will contribute to evaluating the feasibility, preliminary efficacy, and safety of acupuncture in reducing AF burden for persistent AF after CA. The results will be used for the sample size calculation of a subsequent large-scale trial.

Trial registration

Chinese Clinical Trial Registry ChiCTR2000030576. Registered on 7 March 2020.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s13063-020-04967-y.

Efficacy of acupuncture for sciatica: study protocol for a randomized controlled pilot trial

BACKGROUND

Acupuncture is widely used for pain diseases while evidence of its efficacy for sciatica is insufficient. We aim to explore the feasibility and efficacy of acupuncture with different acupoint selecting strategies for sciatica induced by lumbar disc herniation.

METHODS

This is a multicenter, three-arm, patient-assessor-blinded randomized controlled pilot trial. Ninety patients will be assigned randomly into 3 groups including disease-affected meridians (DAM) group, non-affected meridians (NAM) group, and sham acupuncture (SA) group in a 1:1:1 ratio. The trial involves a 4-week treatment along with follow-up for 22 weeks. The primary outcome is the change of leg pain intensity measured by the visual analogue scale (VAS) from baseline to week 4 after randomization. Secondary outcomes include functional status, back pain intensity, and quality of life. Adverse events will also be recorded.

DISCUSSION

The results will inspire the optimal acupuncture strategy for sciatica and help establish a better design as well as power calculation for a full-scale study.

TRIAL REGISTRATION

ChiCTR2000030680 (Chinese Clinical Trial Registry, http://www.chictr.org.cn , registered on 9 March 2020).

[Study on the mechanism of Ca2+-buffering by sodium glycodeoxycholate micelles]

In the present article, NaGDC was used to study the Ca(2+)-buffering capability of bile salt micelles. NaGDC is a naturally occurring bile salt which constitutes approximately 10 molar percent of bile salt composition in gallbladder. The authors selected glycine conjugated bile salts NaGDC because it precipitates with Ca2+ ions fast. The Ca(2+)-buffering property of sodium glycodeoxycholate (NaGDC) micelles was studied by utilizing turbidity titration, quasi-elastic light scattering (QELS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). When the concentration of NaGDC was above the CMC, the precipitation of Ca2+ ions with NaGDC was buffered. The Ca(2+)-buffering capability was enhanced when the concentration of NaGDC increased. The possible mechanism of Ca(2+)-buffering by NaGDC micelles was discussed. When the concentration of NaGDC was below the CMC, the Ca2+ ions reacted with GDC-anions to form the Ca(GDC)2 precipitation. However, at the concentration above the CMC, NaGDC simple micelles were connected by Ca(2+)-bridge to form larger fibriform micelles via the interaction of carboxyl groups of NaGDC simple micelles with Ca2+ ions. When the ratio of Ca2+ to Na+ was enhanced to the fixed value, Na(n)Ca(m) (GDC)(n+2m) complexes were precipitated by the further addition of Ca2+ ions.

[Differential accumulation of the new high-affinity phosphate transporter candidated gene fragment in rice roots in response to phosphorus deficiency stress]

Phosphate is a major constraint to crop production, and phosphate uptake in plant is mainly by high-affinity phosphate transporter under phosphate deficiency condition. Using RT-PCR, a 1,178 bp phosphate transporter gene fragment OjPT1 was cloned from roots of Jingxi17 (Oryza sativa L. ssp. japanica) supplied with no phosphate. The comparison of this sequence with ones in GenBank indicated that it shared about 70% similarity at amino acid level with other phosphate transporters in higher plants, such as Arabidopsis thaliana, potate, tamato, Medicago truncatula and Catharanthus roseus, and high similarity with phosphate transporters in Saccharomyces cerevisiae and Neurospora crassa. RT-PCR assay showed that the OjPT1 transcripts were induced under phosphate deficiency condition. This gene fragment OjPT1 has been deposited in GenBank (accession No. AF249619).

Design and fabrication of a 24-channel acousto-optic spatial light modulator

Acousto-optic (AO) devices are important spatial light modulators. They can be used as light-beam deflectors, rf true-time-delay lines, etc. To increase their spur-free dynamic range, we present what to our knowledge is a novel multichannel AO device structure, in which different channels have different carrier frequencies, so a wideband signal can automatically be decomposed into a set of narrow-band signals. Design, fabrication, and testing of this 24-channel, 10-mus AO spatial light modulator are addressed.

Implementation of a non-zero-order joint-transform correlator by use of phase-shifting techniques

The implementation of non-zero-order joint-transform correlators (JTC's) is presented. The zero-order spectra (i.e., the autocorrelation power spectra) are removed from the joint-transform power spectrum by use of phase-shifting techniques by which the output diffraction and input spatial domain can more efficiently be utilized. Applications of the phase-shifting techniques to both conventional JTC's and phase-transformed input JTC's (PJTC's) are discussed. Compared with the conventional JTC, the PJTC has the advantages of higher light efficiency, a better signal-to-clutter ratio, and the simplicity to realize phase shifting. We anticipate that the proposed non-zero-order JTC's should have a significant impact on the future development of more efficient JTC's.

Performance of a phase-transformed input joint transform correlator

Conventionally a detected image is represented by an intensity array owing to the square-law nature of most detectors. However, this does not mean that we have to restrict ourselves to using intensity images for the correlation process. Transforming intensity images into phase images before correlation, which can be easily realized by a phase-modulation spatial light modulator, offers an alternative approach for high-performance pattern recognition. A phase-transformed input joint transform correlator is investigated in detail in terms of pattern discriminability, detection efficiency, and noise robustness. We show that the phase-transformed joint transform correlator has higher pattern discriminability and detection efficiency than the conventional joint transform correlator, and it also offers a better trade-off between the pattern discriminability and noise tolerance. A proof-of-concept experiment is also provided.

Kinoform-based Nipkow disk for a confocal microscope

A kinoform-based Nipkow-disk system, as applied to a real-time confocal microscope, is presented. The major advantage of this technique must be its high light efficiency (e.g., >80%), which significantly improves the performance of a confocal microscope. Our preliminary experiment indicates that there are potential applications to three-dimensional microscopic imaging as well as to object surface detection.

Multilayer associative memory and its hybrid optical implementation

We propose a multilayer associative memory with a winner-take-all operation on the inner product between an input and stored exemplars. The winner-take-all operation is performed by a unit-step operation with an adaptive-threshold strategy. We show that the multilayer-associative-memory unit-step operation with an adaptive-threshold strategy has a high noise immunity and a large storage capacity, and it is also capable of extending to a gray-level associative memory with a phase-representation technique. A hybrid optical implementation with a proof-of-concept experiment is also provided.

Temperature-compensated fiber specklegram strain sensing with an adaptive joint transform correlator

A temperature-compensated fiber specklegram strain sensor with an adaptive joint transform correlator (JTC) is presented. By exploiting the dual-channel correlation of the fiber specklegram JTC, we can measure the temperature-compensated strain. Experimental results have shown that the strain sensitivity can be as high as 0.1 µstrain/1°C.

Design of a bipolar composite filter by a simulated annealing algorithm

We present the design of a bipolar composite filter (BCF) by a simulated annealing algorithm. By minimizing the energy function of the system, we construct an out-of-plane rotation-invariant bipolar filter. We show that the BCF offers high pattern discrimination capability and can easily be implemented with an electronically addressed spatial light modulator.

Analysis of a fiber specklegram sensor by using coupled-mode theory

The performance of the fiber specklegram sensor (FSS) by use of the waveguide coupled-mode theory is analyzed. The analyses are based on the microbending effect on the sensing fiber, in which we have found that the sensitivity of the FSS is affected by the core diameter and the bending geometry. Experimental confirmations of the analyses are also provided in which we have shown that experimental data are consistent with the analyses.

Phase-encoded input joint transform correlator with improved pattern discriminability

The concept of using phase-encoded input representation in a joint transform correlator is presented, in which we show that the phase-encoded input joint transform correlator is an optimal filtering system that improves detection efficiency and pattern discriminability.

Angle-dependent diffraction efficiency in a thick photorefractive hologram

The diffraction from a thick photorefractive hologram is shown to be angular dependent, which originates mainly from the angle-dependent effective electro-optic coefficient of a photorefractive crystal. The angle dependency of the diffraction causes a nonuniform diffraction over the pixel positions or the spatial frequency contents of a hologram image in a page-oriented holographic system, resulting in a deteriorated reconstructed image. In addition, owing to the angular variations in diffraction, the wavelength-multiplexing scheme should be a better choice than angular one.

Application of position encoding to a complex joint transform correlator

Because a joint transform correlator can be used as a general optical signal processor, complex-impulse-response implementations in the spatial domain are often requested. We introduce a position-encoding technique with which complex-valued references for the joint transform correlator can be obtained with an amplitude-modulated spatial light modulator. A proof-of-concept experiment is also provided.

Dynamic fiber specklegram sensing

We introduce a concept of dynamic sensing that uses fiber speckle fields. By autonomously updating the fiber speckle patterns (i.e., using a moving reference to perform frame-to-frame comparison) on an electronically addressable spatial light modulator, we can exploit the dynamic fiber status. In other words, by joint transforming the rapidly changing speckle patterns from a sensing fiber, we can determine the dynamic aspects of the fiber status. For demonstration, dynamic displacement sensing is illustrated in which we have observed that the rate change and the trend of the fiber perturbation can indeed be detected. We note that the dynamic sensing technique can be applied to a variety of sensing parameters, e.g., strain, stress, temperature, and possibly seismic monitoring.

Implementation of a polychromatic Hamming net for color image classification

A color exemplar-based Hamming net as applied to a color image classifier is presented. The color decomposition and composition techniques for constructing a polychromatic Hamming layer and winner-take-all (WTA) layer interconnection weight matrix (IWM) are discussed. We have simplified the WTA algorithm to reduce the number of iteration cycles in the WTA layer. To confirm the operation of the color Hamming net we provide simulation and experimental demonstrations.

Short-time Fourier transform and wavelet transform with Fourier-domain processing

We discuss the semicontinuous short-time Fourier transform (STFT) and the semicontinual wavelet transform (WT) with Fourier-domain processing, which is suitable for optical implementation. We also systematically analyze the selection of the window functions, especially those based on the biorthogonality and the orthogonality constraints for perfect signal reconstruction. We show that one of the best substitutions for the Gaussian function in the Fourier domain is a squared sinusoid function that can form a biorthogonal window function in the time domain. The merit of a biorthogonal window is that it could simplify the inverse STFT and the inverse WT. A couple of optical architectures based on Fourier-domain processing for the STFT and the WT, by which real-time signal processing can be realized, are proposed.

Application of a fiber-speckle hologram to fiber sensing

A sensitive fiber-speckle field sensor using a Ce:Fe-doped LiNbO(3) photorefractive fiber hologram is introduced. We have shown that the sensitivity of this photorefractive fiber specklegram sensor can be of the order of 0.05 µm. The proposed system would offer the widespread use of practical fiber-sensing applications.

Diffraction properties of a reflection photorefractive hologram

Diffraction properties of a photorefractive hologram have been described previously in most cases with Kogelnik's uncoupled-recording-wave-theory, which was originally derived for nonphotorefractive holograms. Despite its simplicity and good approximation, the theory has shown its practical limitations and discrepancies when the refractive-index perturbation is large. We study the diffraction properties of a reflection photorefractive hologram using a coupled-recording-wave approach. A closed-form expression for the diffraction efficiency is obtained. The important aspect of the new formula is that it predicts a lower cross-talk noise (or, a higher wavelength sensitivity) than Kogelnik's formula. This offers an explanation for the apodization phenomenon (i.e., lower cross-talk noise from the experiment as compared with the analytical result) as found by Rakuljic et al. [Opt. Lett. 17, 1471-1473 (1992)].

Effects of recording-erasure dynamics of storage capacity of a wavelength-multiplexed reflection-type photorefractive hologram

We investigate the effects of the recording-erasure dynamics on the storage capacity of a wavelengthmultiplexed reflection-type photorefractive hologram by using a coupled-recording-wave approach. A closed-form expression for the diffraction efficiency for on-Bragg incidence is derived. The dependence of the equalized diffraction efficiency on the number of recordable holograms is analyzed. The result shows that the storage capacity of a reflection-type hologram is of the same order of a transmission-type hologram but higher than the previous predictions based on an uncoupled-recording-wave theory.

Polychromatic target identification with a color liquid-crystal-TV-based joint-transform correlator

A real-time polychromatic target-detection technique that uses a computer-addressable color liquid-crystal- TV-based joint-transform correlator (JTC) is presented. One of the major features of the polychromatic JTC is that the spectra content of the object can be exploited. Since the liquid-crystal-TV panel is computer addressable, the JTC system can be made adaptive, by which the joint-transform power spectrum can be manipulated. Experimental demonstration of the proposed polychromatic JTC is provided, in which we show that the spatial and the spectral content of targets can be detected.

Shift-invariant interpattern association neural network

A shift-invariant neural network that uses the translation-invariant property of the modulus Fourier spectra with the heteroassociation interpattern association memory is proposed. A binary encoding of a spectral sampling of the training set is used to preserve the main features. Computer simulations and experimental demonstrations are provided that show the shift-invariant property of the proposed optical neural network.

Multimode fiber sensing by using mean-absolute speckle-intensity variation

We present a fiber-sensing technique that detects the mean-absolute speckle-intensity variation between the updated and the reference speckle pattern for determining the environmental perturbation factor (e.g., displacement, temperature, pressure, acoustic wave). We show that the proposed technique is highly sensitive and simple. One of the major advantages of the proposed technique is that it can perform a fast-response measurement with off-the-shelf electronic hardware. Experimental data for submicrometer displacement as well as temperature measurement are provided. To extend the dynamic range of the proposed technique, one can use an updated reference speckle pattern.

Unipolar interpattern association neural networks

A method for constructing a unipolar interconnection weight matrix (IWM) of the interpattern association (IPA) model is presented. By a search of the redundant interconnection links, a method that removes all negative links is introduced. Since the IWM is unipolar, the difficulty of implementing positive and negative IWM's can be avoided. Computer simulation and experimental results show that the unipolar IWM IPA neural network performs better than the bipolar IWM IPA model.

Multitarget detection using spatial synthesis joint transform correlation

A spatial synthesis method that improves accuracy of detection for joint transform multitarget recognition is discussed. The reference function used for the conventional joint transform correlation is replaced by a synthesized function for sharpening correlation profiles without the use of a filter in the Fourier domain. It is shown that the synthesized function can be truncated spatially to fit multiplereference applications and that the effectiveness of this technique is not affected by the number of references. The implementation of the synthesized function, effects caused by noise disturbance, background cluttering, and spectral fringe binarization are investigated.

Cross-talk noise in a wavelength-multiplexed reflection-type photorefractive fiber hologram

We have analyzed the cross-talk noise as affected by the wavelength spread that is due to the spectral width of the light source in a wavelength-multiplexed reflection-type photorefractive fiber hologram. The spectral bandwidth of each multiplexed channel limited by the cross-talk noise is discussed. The signal-to-noise (cross-talk) ratio is analyzed, whereby we have shown that this ratio is sensitive to the separation between adjacent multiplexed channels and to the spectral width of the light source. The cross-talk-limited storage capacity for practical photorefractive fibers is evaluated.

Submicrometer displacement sensing using inner-product multimode fiber speckle fields

A multimode fiber sensor using the intensity inner product of speckle fields is presented. The sensitivity and the dynamic range of the displacement sensing are quantitatively analyzed. We show that the sensitivity of displacement can be in the submicrometer range. Experimental performances show that the results are consistent with the calculated results.

Intensity compensation fiber for joint transform correlation peak enhancement

A spatial filtering technique is proposed to sharpen the correlation peak for a joint transform correlator (JTC) by using the inverse reference power spectrum. Ways of handling the pole problems are discussed under various noise conditions. The minimum mean-square-error method is used to locate the optimum bias value and to estimate threshold level as applied to eradicate the poles. Applications to multitarget recognition and spectral fringe binarization are also studied. Computer-simulated results show that the compensated JTC performs better than the conventional JTC.

Gray-level discrete associative memory

A gray-level discrete associative-memory neural network based on object decomposition and composition is presented. By decomposing a gray-level pattern into bipolar/binary subpatterns, a gray-level discrete associative memory can be constructed from the composition of the subpattern channel results. Preprocessing for removing dc bias and normalizing the gray-level scale is performed on the input gray-level pattern. This eliminates the mismatching and saturation problems caused by bias level, which shifts the pattern gray levels throughout the pattern. Computer-simulation and optical-experimental results for a gray-level interpattern association model are shown to be consistent with the theoretical model.

Multichannel sensing with fiber specklegrams

A fiber specklegram sensor for multichannel sensing is presented. Analyses and experiments show that a fiber specklegram sensor (FSS) is highly sensitive to the modal phasing variation of a multimode-sensing fiber. It is shown that the FSS is less vulnerable to environmental factors than the two-arm interferometric fiber-sensing technique. Because the FSS processes a narrow spectral bandwidth, it is particularly suitable for wavelength multiplexing. One of the major advantages of the FSS must be the multiplexing capability, in which multiparameter sensing can be realized in a single fiber. Applications of the FSS system to acoustic-sensing array, structural fatigue monitoring, and smart emission detection are also discussed.

Effects of thresholding in joint-transform correlation

The joint-transform power spectrum of two identical objects can be represented as a one-dimensional sinusoidal grating modulated by a Fourier transform, and the correlation peaks can be regarded as the first-order diffraction of the grating. The peak intensity and the width are then determined by the aperture and the modulation of the grating. Based on this analysis, it is shown that dc blocking, hard clipping, or binarization of the power spectrum results in higher correlation peak intensity and a narrower peak width. Direct-current blocking is also found to be preferable if the input pattern to the correlator is corrupted by noise.

Optical implementation of the Hamming net

We present an optical implementation of the Hamming net that can be used as an optimum image classifier or an associative memory. We introduce a modified Hamming net, in which the dynamic range requirement of the spatial light modulator can be relaxed and the number of iteration cycles in the second layer (or maxnet) can be reduced. Experimental demonstrations of the optical implementation of the Hamming net are also given.

Compact joint transform correlator with a thick photorefractive crystal

A compact joint transform correlator with a thick photorefractive crystal is presented. We demonstrate that Bragg diffraction severely limits the correlation performance in a thick crystal. To relax the Bragg limitation of the crystal a Galilean telescopic beam compression technique is used in the joint transform correlator.

Relaxation abnormalities in single cardiac myocytes from renovascular hypertensive rats

In myocardial hypertrophy secondary to renovascular hypertension, the rate of intracellular Ca2+ concentration decline during relaxation in paced left ventricular (LV) myocytes isolated from hypertensive (Hyp) rats is much slower compared with that from normotensive (Sham) rats. By use of a novel liquid-crystal television-based optical-digital processor capable of performing on-line real-time Fourier transformation and the striated pattern (similar to 1-dimensional diffraction grating) of cardiac muscle cells, sarcomere shortening and relaxation velocities were measured in single Hyp and Sham myocytes 18 h after isolation. There were no differences in resting sarcomere length, percent of maximal shortening, time to peak shortening, and average sarcomere shortening velocity between Sham and Hyp cardiac cells. In contrast, average sarcomere relaxation velocity and half-relaxation time were significantly prolonged in Hyp myocytes. Contractile differences between Sham and Hyp myocytes detected by the optical-digital processor are confirmed by an independent method of video tracking of whole cell length changes during excitation-contraction. Despite the fact that freshly isolated myocytes contract more rigorously than 18-h-old myocytes, the relaxation abnormality was still observed in freshly isolated Hyp myocytes, suggesting impaired relaxation is an intrinsic property of Hyp myocytes rather than changes brought about by short-term culture. We postulate that reduced sarcomere relaxation velocity is a direct consequence of impaired Ca2+ sequestration-extrusion during relaxation in Hyp myocytes and may be responsible for diastolic dysfunction in hypertensive hypertrophic myocardium at the cellular level.

Redundant-interconnection interpattern-association neural network

We have shown that introducing interconnection redundancy can make a neural network more robust. We describe performances under noisy input and partial input that show that the optimum-redundant interconnection improves both the noise tolerance and the pattern discriminability. Simulated and experimental demonstrations are also provided.

Sensing with fiber specklegrams

The fiber specklegram is highly sensitive to the relative modal phases and is of multiplexing capability. Its properties are analyzed and experimentally demonstrated.