bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic 3D computed tomography for demining and archeological applications
Authors: Stergiopoulos Stergios , Alterson Robert , Havelock David , Grodskil Julius
Published: July 2002

The 3D acoustic tomography concept of this paper combines computerized tomography image reconstruction algorithms using acoustic diffracting waves together with depth information to produce a novel, three-dimensional image of an underground section. The new method illuminates the ground with an array of acoustic sources along equally spaced points on the circumference of a surface of interest. For each transmitted pulse, the reflected–refracted signals are received by a line array of acoustic sensors located at a diametrically opposite point from the acoustic source line array. For a given depth, which is represented by a time delay in the received signal, a horizontal tomographic 2D image is reconstructed from the received projections. Integration of the depth dependent sequence of cross-sectional reconstructed images provides a complete three-dimensional overview of the inspected terrain. The method has been tested with an experimental system that consists of a line array of 4 acoustic sources, providing plane waves, and a receiving line array of 32 acoustic sensors. Real results indicate that the performance characteristics of the new method are affected by the reflective acoustic energy from above the ground objects and the very poor signal-to-noise ratio of the received signal due to the poor air–ground coupling.
Microbubbles and medical ultrasound: Translation dynamics and optimal driving
Authors: Reddy Anil J. , Szeri Andrew J.
Published: July 2002

If bubbles are to be used in a medical setting, for example as contrast agents in the imaging of tissue, or in the delivery of a drug to a blood clot or tumor, it is necessary to characterize the translational motion of a bubble subjected to acoustic excitation in the form of ultrasound. Further, because bubbles remain undissolved in a fluid for only a short period of time, it may be necessary to transport a bubble to its target location as quickly as possible. The acoustic radiation force, known as the primary Bjerknes force, and the recently derived expression [J. Magnaudet and D. Legendre, Phys. Fluids 10, 550–554 (1998)] for drag force acting on a bubble with time-dependent radius, are taken into account in developing an equation governing the translation dynamics of a bubble. This is used together with the Rayleigh–Plesset equation for volume oscillations and optimal control theory to design the ideal acoustic excitation for transporting a bubble to a particular location, or for maintaining the position of a bubble at the target location despite the adverse flow of the surrounding fluid, as in the case of a bloodstream. [Work supported by NSF.]
Using ultrasound to assess change in corneal stiffness
Authors: Hastings Mardi C.
Published: July 2002

Corneas of six intact donor eye globes from five different species were interrogated with continuous wave ultrasound (15 MHz) while being excited by audible sound waves. The corneal oscillation induced by the audible stimulus created a phase modulation in the received ultrasonic signal which was demodulated to obtain the amplitude and phase of the motion at discrete locations on the cornea as defined by the crossed beams of the ultrasonic transmitter and receiver. The complex stiffness parameters for each cornea were determined from a curve fit to the measured amplitude and phase of the transfer function relating the dynamic motion of the cornea to the local acoustic field. Data were recorded at three different intraocular pressures. Increasing intraocular pressure resulted in increasing corneal stiffness to produce measurable shifts in resonance peaks observed in the dynamic response. Noninvasive assessment of corneal stiffness as demonstrated in this study has potential application in diagnosing and treating glaucoma, and monitoring healing after injury or cornea surgery.
Raman–Ray whispering gallery experiment and enhanced backscattering from merged caustics: Optical analogies of acoustical wavefields
Authors: Marston Philip L. , Barnes Charles C. , Zhang Yibing B. , Thiessen David B.
Published: July 2002

Two optical experiments for viewing wavefields associated with acoustical processes are demonstrated. The first is a modern version of a little-known whispering gallery experiment by Raman and his associate Ray [C. V. Raman and G. A. Sutherland, Proc. R. Soc. London, Ser. A 100, 424–428 (1922); B. Ray, Bull. Calcutta Math. Soc. 12, 225–230 (1922)], which simulate wavefields for a source on a curved reflecting surface. Our simulation uses a long, narrow front-surface mirror bent uniformly by attached weights. The light source is the diffraction of laser light by a knife edge placed adjacent to the mirror. The caustic associated with once-reflected rays (a cardioid curve) is easily distinguished as are other caustics associated with rays having only a few reflections. Amplitude contributions near each caustic are approximated by Airy functions. The second experiment is analogous to an acoustical backscattering enhancement by bluntly truncated tilted penetrable circular cylinders associated with the merging of end-reflected rainbow caustics [F. J. Blonigen and P. L. Marston, J. Acoust. Soc. Am. (in press)]. Light backscattered by a tilted blunt glass fiber displays the merged caustics for the appropriate tilt. [Work supported by ONR and NSF-CRDC.]
Hybrid tool for quick characterization of multi-layered panels
Authors: Sow Ibrahima , Beslin Olivier , Nicolas Jean
Published: July 2002

With the advancement of science and technology, materials with high damping capabilities and high modulus of elasticity are increasingly popular as they reduce vibration and noise. However, most of the time, there is a lack of tools that allow quick and easy characterization of the effective materials properties when used in 2-D structures. In this paper, a method is proposed for the characterization and analysis of viscoelastic composite material consisting of a three-ply sandwich panel. The method is based on a quick PC-based numerical code (involving hierarchical finite element method coupled with Beraneks formulation of sandwich panels) and a dedicated simple experimental setup. This approach ensures (i) proper extraction of the equivalent properties such as the modulus of elasticity, the loss factor according to temperature, or frequency of the entire sandwich composite, (ii) characterization of any core viscoelastic resin, and (iii) evaluation of vibroacoustics indicators. The method is validated using commercially available 3M ISD112 and good agreement is found between experimental and numerical results. The method is then used to carry out a parametric study for different panel configurations according to temperature and frequency in order to characterize a viscoelastic resin.
Threshold comparisons for intensity-based duplex perception for speech
Authors: Hall Michael D.
Published: July 2002

Duplex perception (DP) occurs when a stimulus component simultaneously contributes to two percepts (Rand, 1974). A proposed DP variant involves substituting a tone glide for an F3-transition in a /da/ or /ga/ syllable. At full intensity the glide is perceived as a nonspeech chirp that simultaneously distinguishes the consonant. It also has been claimed that the glide contributes to speech (consonant) perception over a range of intensities that are insufficient for nonspeech (chirp) detection, raising the possibility that a phonetic module takes precedence over nonspeech perception (Whalen and Liberman, 1987). Others have failed to find a range of precedence when chirp detection thresholds were reevaluated using a 2AFC task (Bailey and Herrmann, 1993). Which conclusion is valid? The current investigation addressed this question by comparing individual thresholds for consonant perception and chirp detection using a variety of methods. Chirp detection thresholds were evaluated using the method of constant stimuli, 2AFC, and various reminder tasks (using a fixed standard). Thresholds for consonant perception were evaluated using identification and discrimination (same-different) tasks. Results analyzed according to both traditional threshold and detection theories support the claims for a range of precedence and suggest that discrepant chirp detection thresholds reflect a reliance on consonant perception.
Vowel reproduction exhibits an intrinsic dynamic organization
Authors: Tuller Betty , Vallabha Gautam K.
Published: July 2002

Speech perception and production are generally thought to be tuned by the speaker’s linguistic environment. If so, iterative reproduction of a vowel by a single speaker may amplify subtle biases introduced by the tuning. Four male monolingual speakers of American English were asked to reproduce 100 synthetic vowel-like stimuli, uniformly distributed in a two-formant acoustic space (F1, F2 varying, F0=120 Hz, F3=2500 Hz, duration=200 ms). Fifteen of the subject’s own productions were chosen for serial reproduction, as follows: Each original production was presented to the subject through headphones, and the subject immediately mimicked it. After a 0.5-s delay, the ‘‘mimic’’ was played back to the subject as the target for his next production. This second mimic was the target for the following production, and so on, for ten iterations. Subjects made systematic errors in reproducing their own vowel sounds, and sequences of serially reproduced vowels behaved differently in different parts of the vowel space. These results suggest that some vowel regions are preferred over other regions, indicating that the cognitive processes for perceiving and producing vowels have complex intrinsic dynamics. [Work supported by NIMH.]
Consonants and vowels behave differently in silent center syllables
Authors: Kang A. Min , Whalen D. H.
Published: July 2002

Compared to consonants, steady-state vowels show no right ear advantage, activate different brain regions, and only trigger categorical perception when extremely short. Auditory explanations for this distinction assume different perceptual mechanisms for brief, dynamic consonants and long, slow-changing vowels. Gestural views suggest steady-state vowels are perceived as only partially speechlike. The present study compares consonant and vowel identification and discrimination when based on the same brief, dynamic information in the form of silent center (SC) syllables. The CVCs simultaneously varying in equal-sized F2 steps along both a /b-d/ and an /ε-Λ/ continuum were synthesized (full syllables). The SC syllables were produced by replacing the middle 60% with silence. Relative to full syllables, overall SC consonant discrimination improved from chance to 70%; vowel discrimination dropped from 85% to 70%. The SC vowel identification was affected by consonantal context but the reverse effect was weaker. Improved SC consonant discrimination may result from decreased masking or greater prominence of the consonant gesture. Decreased SC vowel discrimination could result from reduced acoustic information or weaker prominence of the inferred vowel gesture. While these results do not distinguish auditory and gestural theories, they do place the consonant/vowel distinction in a new perspective. [Work supported by NIH Grant No. HD-01994.]
Separable effects of neighborhood density and phonotactic probability on word recognition in speech
Authors: Large Nathan R. , Luce Paul A.
Published: July 2002

Previous research on the effects of probabilistic phonotactics on spoken word recognition has typically confounded phonotactics and similarity neighborhood density. In the present research, the inhibitory effects of density and facilitative effects of probabilistic phonotactics on spoken word processing were manipulated simultaneously. Four sets of monosyllabic words and nonwords were created by orthogonally combining two levels of neighborhood density and two levels of probabilistic phonotactics. Speed and accuracy were examined in three different experimental paradigms: single-word shadowing, A-X same–different matching, and speeded neighbor generation. Words and nonwords were either blocked by lexicality or intermixed. Blocking and mixing of stimuli were used to manipulate participants’ focus on lexical and sublexical levels of processing. In part, our results demonstrate simultaneous effects (inhibitory and facilitative) of both density and phonotactics. The implications of our results for models of spoken word recognition and lexical access will be discussed.
Weiss–Weinstein bound for matched-field parameter estimation
Authors: Xu Wen , Baggeroer Arthur B.
Published: July 2002

Matched-field parameter estimation, including source localization and environmental parameter estimation, is often implemented based on an ambiguity surface. The ambiguity surface is derived from the correlation between the observed signal field and the modeled signal field, and is often characterized by a multimodal structure since the typical signal field is a highly nonlinear function of the embedded parameters. In the presence of noise or other interferences, a high sidelobe level leads to a large error probability in parameter estimation. This sidelobe effect increases as the signal-to-noise ratio (SNR) decreases such that, below a threshold SNR, the estimation mean-square-error (MSE) is dominated by the error around the sidelobes, which is not predicted by the Cramer-Rao bound (CRB). To analyze this effect, the Weiss–Weinstein bound (WWB) is presented for the attainable performance of matched field methods. The bound is expressed in terms of the SNR and an ambiguity function defined based on the Green’s function both at the receiver array. An evaluation example demonstrates how the ambiguity behavior, particularly the sidelobe structure, affects the bound’s evaluation in different SNR regions and leads to the well-known threshold phenomenon in nonlinear parameter estimation.
Sensitivity analysis of an estimator-correlator
Authors: Schwenke Roger W. , Sibul Leon H.
Published: July 2002

The estimator-correlator (EC) is a maximum likelihood-sense optimum detector for detection of objects that have multiple random highlights rather than a single deterministic highlight. The EC is also a model-based signal processor that uses target scattering function as an a priori statistical model. This EC has uses in sonar, medical ultrasound, and multipath communication channels. The receiver operator characteristics (ROCs) of this EC are derived. A sensitivity analysis is derived which computes the change in the ROC curve when there are errors in the a priori estimate of the scattering function. Examples of common scattering function errors and the resulting change in sensitivity are given. [This work has been supported by ONR, Code ONR333, Ms. Khine Latt Program Officer.]
Case studies of ‘‘cafetorium’’ spaces in schools
Authors: Siebein Gary W. , Gold Martin A.
Published: July 2002

Case studies of ‘‘cafetorium’’ spaces in elementary and high schools were conducted to evaluate the performance of this hybrid room approach. Many schools, in an effort to reduce costs, attempt to create hybrid spaces that will accommodate multiple functions. One result of this effort is the cafetorium. This study includes issues raised in establishing design criteria with architects and clients; acoustic space planning, organization, and other preliminary design issues; budget, design criterial, and material selection issues; acoustic models and prediction tools; background noise and noise control issues; sound system integration; constructed spaces and follow-up acoustical measurements; and client and user comments regarding the performance of the spaces. Each specific issue is presented within the context of built projects ranging in scope from new elementary school projects to renovations of high school projects. The case studies present issues regarding the relationship between established acoustical design criteria, prediction tools, architectural integrity, and budgetary constraints as determiners of successful spaces for listening and learning.
Characterization of acousto-electric drop arrays with application to evaporation studies
Authors: Zheng Yibing , Apfel Robert E.
Published: July 2002

An acousto-electric levitator has been developed to study liquid drop and solid particle clusters and arrays. This device uses both an acoustic standing wave and a high dc electric field simultaneously to form and levitate several charged drops in a two-dimensional array in air. A 2-D theoretical model is employed to study the profile of the acoustic field and the forces that hold the arrays at the center of the levitator. A study of the evaporation of alkane drops and arrays has been performed. It is shown that when a minimal acoustic field is used to levitate drops (by compensating with an electric field), the evaporation rate in the acousto-electric levitator is almost the same as that of drops suspended by a glass fiber. The experimental results for an isolated drop are compared with the theory of a quasi-steady model. The point source method is used to calculate theoretically the results for array evaporation. Both single and multiple component drops are studied. [Work supported by NASA (NAG3-2147) and by NSF (CTS-9870015).]
Regularized matched-mode localization with environmental mismatch
Authors: Dosso Stan E. , Collison Nicole E.
Published: July 2002

This paper considers a new approach to matched-mode processing (MMP) for source localization. The MMP consists of decomposing far-field acoustic data to obtain the modal excitations, then matching these with modeled replica excitations. A potential advantage of MMP over matched-field processing (MFP) is that subsets of the complete mode set can be considered. For example, if geoacoustic properties are poorly known, the matching can be applied only to low-order modes that interact minimally with the seabed. However, modal decomposition can be ill posed and unstable if the sensor array does not adequately sample the acoustic field. For such cases, standard decomposition methods yield minimum-norm solutions that are biased towards zero. Although these methods provide mathematical solutions (stable solutions that fit the data), they may not represent physically meaningful solutions. The new approach of regularized MMP (RMMP) carries out an independent decomposition prior to comparison with the replica excitations for each grid point, using the replica itself as the prior estimate in a regularized inversion. This provides a more meaningful decomposition near the actual source location. In this paper, RMMP, MMP, and MFP are compared for realistic test cases, including various sensor array configurations, as well as environmental mismatch in seabed properties.
Localization analysis based on subband processing of broadband LFM signals
Authors: Haralabus Georgios
Published: July 2002

The increased utilization of broadband signals in underwater research and development is related to sonar performance enhancement in littoral waters, optimum operational frequency selection, and interplatform, multisensor experimental settings requiring frequency compatibility. Preliminary wide-band experiments indicate potential performance improvement in reverberation-limited environments. Here the frequency dependence of active broadband detection/localization is examined based on 1200-Hz LFM signals (2300–3500 Hz). A subband matched filter scheme is devised according to which a replica of the transmitted pulse is segmented into ten 120-Hz subbands. Although comparison of source localization indicates comparable performance of all subbands, ping-to-ping variability of the ten correlator outputs suggests that the detection performance maybe improved by employing incoherent processing schemes. Doppler effects and subband detection synchronization problems that lead to performance degradation in large time-bandwidth signal scenarios are addressed. A method to estimate range rate (relative velocity between source and receiver) based on single ping differential time delay between subband matched filter outputs is developed. This intraping technique is an alternative to the standard interping method which requires multiping detection history.
Detection threshold of echo signals in a noise-free environment by the Atlantic bottlenose dolphin
Authors: Au Whitlow W. L. , Lemonds David , Vlachos Stephanie , Nachtigall Paul E.
Published: July 2002

The Atlantic bottlenose dolphin has a sonar detection range of 72 m for a 2.54-cm solid sphere and 113 m for a 7.63-cm water-filled sphere in a noise-limited environment. However, there are many natural environments in which the ambient noise is low and will not mask a dolphin auditory system. The dolphin’s detection range for the same 2.54- or 7.62-cm sphere in a nonmasking environment should be considerably longer than 72 and 113 m, respectively. In order to perform a sonar experiment in an environment where the ambient noise is low, a pool must be extremely large, or an outdoor facility with low ambient noise conditions would need to be available. Another way of approaching this problem is to perform a passive listening experiment in which the signal presented to a dolphin simulates an echo from a specific target. We performed a listening experiment using both pure tones and simulated broadband echo from a 7.62-cm water-filled sphere. The detection threshold for narrow-band tonal signals (audiogram) is compared with the detection threshold for a broadband echo signal in order to determine the relationship between an audiogram and sonar detection. The results obtained with the broadband echo also represent the sonar detection range of a dolphin in a nonmasking environment. [Work suported by ONR.]
High spatial density measurements of the vibro-acoustic response of some aircraft structures
Authors: Herdic Peter C. , Houston Brian H. , Williams Earl G.
Published: July 2002

Experiments involving spatially dense interior pressure and surface velocity measurements (10–1000 Hz) on aircraft structures both in the laboratory and in-flight are reported. In the laboratory experiments, the structures were predominately excited by point forcing functions applied at a number of locations on the fuselage. The structural-borne energy couples energy into the interior at resonant frequencies of both the structure and the interior cavity. The normal modes of the cavity tend to dominate the problem at frequencies above 100–200 Hz where the density of states is very high. Further, we also report on in-flight measurements involving the use of a scanned microphone array (55 microphones at 32 axial stations) in the passenger cabin of a turbo-prop powered aircraft. The surface velocity was determined through near-field acoustic holography (NAH). The counter-clockwise rotating propellers sweep past the fuselage, resulting in a slap of air pressure on the aircraft sidewalls. This motion creates a dominant antisymmetric (left/right) surface velocity and interior pressure distribution at the blade passage frequency and its harmonics. The results associated with two laboratory experiments and one in-flight experiment, along with some comparisons to complex three-dimensional finite element-infinite element numerical models, will be reported.
Effects of auditory and visual stimuli on motor facilitation of speech muscles
Authors: Aravind N. K. , Sundara Megha , Chen Robert
Published: July 2002

Transcranial magnetic stimulation (TMS) was applied to the left motor cortex during presentation of video and audio speech stimuli. Motor evoked potentials (MEPs) were recorded from the right orbicularis oris muscle which is activated during pronunciation of the consonant /ba/ but not the consonant /ta/. Subjects were instructed to pay attention to six types of stimuli video presentation of the consonant /ba/, audio presentation of /ba/, audio and video presentation of /ba/, video presentation of /ta/, audio presentation of /ba/ with time-locked video presentation of video /ta/, and the face of the speaker when he was silent. The MEPs were enhanced only when subjects were visually presented with the consonant /ba/. Auditory presentations of the same consonant failed to elicit similar enhancement. The results from visual observation of the consonant /ba/ support other studies of motor facilitation in limb control research in monkeys and humans. In these studies observation of a motor action present in the repertoire of the animal results in enhanced MEPs representing automatic, covert retrieval of the matching action in the premotor cortex. This retrieval is, however, modality dependent. Auditorily presented signals do not trigger action retrieval from the premotor cortex in an identical way.
Constancy of loudness of pipe organ sounds at different locations in an auditorium
Authors: Harrison J. M. , Thompson-Allen N.
Published: July 2002

Pipe organ sounds, as judged by ear, tend to remain constant across different locations in an auditorium, yet the SPL of line spectra may vary by a maximum of 26 dB (mean 8.98 dB, s.d. 2.5), and the overall level may vary, typically, 10 to 12 dB from location to location. However, organs are designed, listened to, and regulated using the psychophysical units of loudness and timbre, and it is possible that the heard sound constancy exists at the psychophysical level. The present work recorded the sound of the C’s and G’s of pipe organ stops at three different locations in a church. The sound pressure levels were transformed to loudness. Similarity of loudness across the locations was measured two ways. First, the bass to treble distribution of loudness across the compass was measured using cross-correlation functions across pairs of locations. Second, the degree of similarity of loudness at the different locations was quantified by calculating ratios of loudness between the different locations. By these measures, the bass to treble loudness distribution and absolute loudness of the reeds were found to be nearly identical at the three locations. Two psychophysical processes were shown to be responsible for the loudness constancy. The first depended upon the power summation of harmonics within each third octave band above band 9 which contain two or more harmonics. The power summation of these harmonics greatly reduced the effect of SPL variability of the line spectra contained within these higher numbered bands. The second depended upon interharmonic loudness summation and upward masking of the first six harmonics. Greater loudness variability at the different locations was found after transforming the SPL measurements of two 8-ft diapasons to loudness compared with the reeds. The larger loudness variability was due to the smaller number of harmonics above the third of the diapasons compared with the reeds. The psychoacoustic measures indicate what a listener will hear as he/she moves among the locations.
Children's memory and suggestibility years later: Age, distress, and attachment
Authors: Gonzalves Lauren , Chae Yoojin , Wang Yan , Widaman Keith F. , Bederian‐Gardner Daniel , Goodman‐Wilson Miranda , Thompson Ross A. , Shaver Phillip R. , Goodman Gail S.
Published: July 2022

The accuracy of children's long‐term memory for distressing events is of theoretical and legal interest. In this longitudinal study, 3‐ to 5‐year‐olds and their main parental caretakers individually participated in a mildly distressing event, and 1 h later the children's memory/suggestibility was assessed (Time 1). Six to seven years later (Time 2), the children (9‐ to 12‐year‐olds, N = 54) were again interviewed about the Time 1 experience. Their memory was more accurate at Time 1 than Time 2. Children who were rated as more distressed at Time 1 recalled more units of correct information at Time 2 if the children were older or lower in self‐reported attachment anxiety. Children who were older at Time 2 were less suggestible. Time 1 misinformation did not contaminate Time 2 free recall. Theoretical and applied implications are discussed.
Improving the Defect Tolerance of PBF‐LB/M Processed 316L Steel by Increasing the Nitrogen Content
Authors: Stern Felix , Becker Louis , Cui Chengsong , Tenkamp Jochen , Uhlenwinkel Volker , Steinbacher Matthias , Boes Johannes , Lentz Jonathan , Fechte-Heinen Rainer , Weber Sebastian , Walther Frank
Published: July 2022

Nitrogen (N) in steels can improve their mechanical strength by solid solution strengthening. Processing N‐alloyed steels with additive manufacturing, here laser powder bed fusion (PBF‐LB), is challenging as the N‐solubility in the melt can be exceeded. This degassing of N counteracts its intended positive effects. Herein, the PBF‐LB processed 316L stainless steel with increased N‐content is investigated and compared to PBF‐LB 316L with conventional N‐content. The N is introduced into the steel by nitriding the powder and mixing it with the starting powder to achieve an N‐content of approximately 0.16 mass%. Thermodynamic calculations for maximum solubility to avoid N outgassing and pore formation under PBF‐LB conditions are performed beforehand. Based on the results, a higher defect tolerance under fatigue characterized by Murakami model can be achieved without negatively influencing the PBF‐LB processability of the 316L steel. The increased N‐content leads to higher hardness (+14%), yield strength (+16%), tensile strength (+9%), and higher failure stress in short time fatigue test (+16%).
Engineering H2O2 and O2 Self‐Supplying Nanoreactor to Conduct Synergistic Chemiexcited Photodynamic and Calcium‐Overloaded Therapy in Orthotopic Hepatic Tumors
Authors: Chen Ying‐Chi , Liu Yu‐Ju , Lee Chin‐Lai , Pham Khang‐Yen , Manoharan Divinah , Thangudu Suresh , Su Chia‐Hao , Yeh Chen‐Sheng
Published: July 2022

Photodynamic therapy (PDT) is traditionally ineffective for deeply embedded tumors due to the poor penetration depth of the excitation light. Chemiluminescence resonance energy transfer (CRET) has emerged as a promising mode of PDT without external light. To date, related research has frequently used endogenous hydrogen peroxide (H2O2) and oxygen (O2) inside the solid tumor microenvironment to trigger CRET‐mediated PDT. Unfortunately, this significantly restricts treatment efficacy and the development of further biomedical applications because of the limited amounts of endogenous H2O2 and O2. Herein, a nanohybrid (mSiO2/CaO2/CPPO/Ce6: mSCCC) nanoparticle (NP) is designed to achieve synergistic CRET‐mediated PDT and calcium (Ca2+)‐overload‐mediated therapy. The calcium peroxide (CaO2) formed inside mesoporous SiO2 (mSC) with the inclusion of the chemiluminescent agent (CPPO) and photosensitizer (Ce6) self‐supplies H2O2, O2, and Ca2+ allowing for the subsequent treatments. The Ce6 in mSCCC NPs is excited by chemical energy in situ following the supply of H2O2 and O2 to produce singlet oxygen (1O2). The nanohybrid NPs are coated with stearic acid to avoid decomposition during blood circulation through contact with aqueous environment. This nanohybrid shows promising performance in the generation of 1O2 for external light‐free PDT and the release of Ca2+ ions for Ca2+‐overloaded therapy against orthotopic hepatocellular carcinoma.
p‐TSA‐Mediated Four‐Component Reaction: One‐Step Access to Mesoionic 1H‐Imidazol‐3‐ium‐4‐olates, Direct NHC Precursors
Authors: Cankařová Naděžda , Nemec Ivan , Krchňák Viktor
Published: July 2022

p‐TSA‐mediated four‐component condensation is described. The reaction of an isocyanide, amine, aldehyde, and amide catalyzed by p‐TSA afforded diversely substituted mesoionic 1H‐imidazol‐3‐ium‐4‐olates in one step. These products were obtained in good to excellent HPLC purity under mild reaction conditions. This formation of mesoionic compounds, structurally related to sydnones and münchnones, represent attractive intermediates and direct precursors for anionic N‐heterocyclic carbenes. Atom economy, time efficiency, and commercially available starting materials make this one‐pot synthesis user‐friendly.

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Palladium‐Catalyzed Regioselective C4 Functionalization of Indoles with Quinones
Authors: Aslam Mohammad , Devkota Shreedhar , Jamshaid Sana , Rok Lee Yong
Published: July 2022

A synthetic strategy for the installation of diversely functionalized quinones at the C4 position of indoles is developed via palladium‐catalyzed C−H and double C−H functionalization. This synthetic protocol provides a rapid route to a variety of 4‐quinonylindoles via the direct coupling of 3‐formylindoles with quinones. Furthermore, this synthetic methodology also efficiently affords biologically interesting bis(indol‐4‐yl)quinones in good yields by direct one‐pot double C−H activation of 3‐formylindoles with the corresponding quinones.

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Survival outcomes of laparoscopic versus open total gastrectomy with nodal dissection for gastric cancer in a high‐volume Japanese center: A propensity score‐matched analysis
Authors: Kinoshita Takahiro , Akimoto Eigo , Yura Masahiro , Yoshida Mitsumasa
Published: July 2022

Aim

To compare the survival outcomes of laparoscopic total gastrectomy (LTG) with those of open total gastrectomy (OTG) in gastric cancer.

Methods

Using an in‐house database, this single‐center study reviewed clinical data for patients who underwent surgery for gastric adenocarcinoma in 2008–2018. The patients were divided into an LTG group and an OTG group.

Results

Data for 638 patients were screened. After exclusions, 580 patients (LTG, n = 212; OTG, n = 368) were enrolled. Noting that the OTG group included more advanced tumors, 1:1 propensity score matching was implemented to reduce any selection bias, leaving 326 patients (LTG, n = 163; OTG, n = 163; pStage I/II/III = 147/87/92) for further analysis. The operation time was longer and blood loss was less in the LTG group. The postoperative hospital stay was shorter in the LTG group than in the OTG group (9 d vs 10 d；P = .040). There was no significant difference in the incidence of grade III or worse postoperative complications (8.9% vs 11.0%). Five‐year overall survival was better in the LTG group (84.9% vs 73.5%; P = .0010, log‐rank test), but there was no significant difference in overall survival according to pStage (I, 93.0% vs 89.0%; II, 85.8% vs 77.5%; III, 64.1% vs 52.5%). There was a similar trend in relapse‐free survival. Distribution of recurrence sites was comparable.

Conclusion

LTG may provide survival outcomes similar to those of OTG when performed by an experienced surgical team. Further evidence is required for final conclusions, especially regarding its efficacy for stage II/III.
Novel CTNNB1 variant leading to neurodevelopmental disorder with spastic diplegia and visual defects plus peripheral neuropathy: A case report
Authors: Spagnoli Carlotta , Salerno Grazia G. , Rizzi Susanna , Frattini Daniele , Koskenvuo Juha , Fusco Carlo
Published: July 2022

Pathogenic variants in the β1‐catenin (CTNNB1) gene have been identified in patients with various diseases, including syndromic intellectual disability, autism spectrum disorder, familial exudative vitreoretinopathy, and neurodevelopmental disorder with spastic diplegia and visual defects (NEDSDV). We report on the clinical, genetic, neuroimaging, and neurophysiological data of a 15‐year‐old patient with complex hereditary spastic paraplegias with exotropia, dyskinesia, and cerebellar signs and a so‐far unreported demyelinating (mainly sensory) polyneuropathy in her lower limbs. She carries the novel, de novo, likely pathogenic heterozygous c.603_605delinsAATA, p.(Met202Ilefs*6) frameshift variant in the CTNNB1 gene. Although peripheral neuropathy was not previously associated with NEDSDV, in light of the role of β1‐catenin as a junction protein in the peripheral as well as in the central nervous system documented in experimental studies, it might represent a causally linked and under‐reported finding to be further explored.
Repetitive Thiazolidine Deprotection Using a Thioester‐Compatible Aldehyde Scavenger for One‐Pot Multiple Peptide Ligation**
Authors: Nakatsu Koki , Okamoto Akimitsu , Hayashi Gosuke , Murakami Hiroshi
Published: July 2022

Strategies for one‐pot peptide ligation enable chemists to access synthetic proteins at a high yield in a short time. Herein, we report a novel one‐pot multi‐segments ligation strategy using N‐terminal thiazolidine (Thz) peptide and a newly designed formaldehyde scavenger. Among the designed 2‐aminobenzamide‐based aldehyde scavengers, 2‐amino‐5‐methoxy‐N′,N′‐dimethylbenzohydrazide (AMDBH) can remarkably convert Thz into unprotected cysteine at pH 4.0. Furthermore, AMDBH degrades Thz at a considerably low rate at pH 7.5, and thioester degradation caused by this scavenger is negligible. As a result, we have developed an efficient one‐pot peptide ligation strategy by simply repetitively changing the pH with AMDBH. Finally, we synthesize mono‐ubiquitinated histone H2A.Z (209 amino acids) via AMDBH‐mediated one‐pot four‐segment peptide ligation in good yield.
3D Printed CO2‐Based Triblock Copolymers and Post‐Printing Modification
Authors: Wei Peiran , Bhat Gulzar A. , Cipriani Ciera E. , Mohammad Hamza , Schoonover Krista , Pentzer Emily B. , Darensbourg Donald J.
Published: July 2022

We report the facile synthesis and 3D printing of a series of triblock copolymers consisting of soft and hard blocks and demonstrate that alkene pendant groups of the hard block can be covalently modified. The polymers are prepared using a salenCo(III)TFA/PPNTFA binary catalyst system and 1,2‐propanediol as a chain transfer agent, providing an efficient one‐pot, two‐step strategy to tailor polymer thermal and mechanical properties. Thixotropic inks suitable for direct ink write printing were formulated by dissolving the block copolymers in organic solvent and dispersing NaCl particles. After printing, porous structures were produced by removing solvent and NaCl with water to give printed structures with surfaces that could be modified via UV‐initiated thiol‐ene click reactions. Alternatively, a tetra‐thiol could be incorporated into the ink and used for cross‐linking to give objects with high solvent resistance and selective degradability.
Precursor Engineering to Reduce Processing Temperature of ZnO Films for Flexible Organic Solar Cells
Authors: Jiang Pei , Chen Jianping , Qin Fei , Liu Tiefeng , Xiong Sixing , Wang Wen , Xie Cong , Lu Xin , Jiang Youyu , Han Hongwei , Zhou Yinhua
Published: July 2022

Sol‐gel‐derived ZnO is one of the most widely used electron‐transport layers in inverted organic solar cells. The sol‐gel ZnO precursor consists of zinc acetate dehydrate (ZAH) and ethanolamine dissolved in 2‐methoxyethanol, where ethanolamine chelates with ZAH, which helps ZAH dissolve in the 2‐methoxyethanol. However, an annealing temperature above 120 °C is required to convert the complexes into ZnO. High temperatures are incompatible with flexible plastic substrates such as polyethylene terephthalate. In this work, we report an amine‐free recipe consisting of ZAH in methanol to prepare ZnO films. The complex formed in the amine‐free precursor solution is methanol‐solvated ZAH, which is simpler than that of the amine‐containing precursor solution. The temperature required for converting the precursor complex into ZnO was reduced to 90 °C for the amine‐free recipe. Low‐temperature‐processed ZnO can function efficiently as an electron‐transport layer in both rigid and flexible inverted nonfullerene solar cells.
Design of Specific Nucleic Acid‐Based Biosensors for Protein Binding Activity
Authors: Fortunati Simone , Pedrini Federica , Del Grosso Erica , Baranda Pellejero Lorena , Bertucci Alessandro
Published: July 2022

Nucleic acid‐based biosensors for the detection of specific proteins combine the typical programmability of synthetic DNA systems with artificially controlled DNA‐protein communication. The high‐affinity interaction between a target protein and a specific ligand, such as an aptamer sequence, or a double stranded DNA domain, or a small peptide, is paired with a nature‐mimicking molecular mechanism allowing for probing, processing, and translating protein binding activity into a measurable signal. In this Review, two main strategies developed in the context of protein‐responsive nucleic acid‐based biosensors are discussed. One is the design of proximity‐based assays harnessing the spatial colocalization of functional probes within the volume of a multivalent protein. The other is the engineering of dynamic DNA structures that undergo a controlled conformational or structural change upon protein binding. Examples of applications from optical and electrochemical detection of antibodies in biofluids to fluorescence imaging of transcription factors in living cells are reported, and suggestions along with possible future directions in the field are discussed.
Clinical Issues—August 2022
Authors: Wright Renae
Published: July 2022

THIS MONTH

Use of sterile vests

Key words: sterile technique, surgical attire, gown, contaminated, back.

Bare arms for unscrubbed personnel

Key words: long sleeves, cover jacket, disposable jacket, patient skin antisepsis, surgical site infection (SSI).

Preventing thermal injury from electrosurgical devices

Key words: electrosurgical unit (ESU), monopolar electrosurgical device, electrode, alternate site thermal injury, burn.

Preoperative site marking for minimally invasive procedures

Key words: surgical site, wrong‐site surgery, alternative site marking, point of access, preprocedure verification.
Therapeutic drug monitoring of caffeine and its primary metabolites in plasma using LC–ESI–MS/MS for apnea of prematurity treatment: Evaluation of ultrapure water as a surrogate matrix
Authors: Long Jia‐Yi , Hu Ya‐Hui , Xia Ying , Du Fei‐Fei , Dai Hao‐Ran , Tian Man , Xu Jing , Cheng Rui , Ding Xuan‐Sheng , Guo Hong‐Li , Chen Feng
Published: July 2022

The growing evidence has endorsed the view that therapeutic drug monitoring of caffeine for apnea of prematurity is helpful for dose tailoring when the therapeutic response is lacking or toxicity is suspected. However, plasma without caffeine is difficult to obtain. Therefore, a method was developed and validated to measure caffeine and its three primary metabolites (paraxanthine, theobromine and theophylline) using LC–ESI–MS/MS in human plasma and several surrogate matrices. The chromatographic separation of analytes was finally achieved on a Waters Symmetry C18 (4.6 × 75 mm, 3.5 μm) column. Several strategies were successfully applied to overcome the matrix effects: (a) appropriate dilution for sample cleanup; (b) a starting lower proportion of organic phase; and (c) multiple individual stable‐labeled isotopic internal standards. The parallelism between the authentic matrix and surrogate matrices was convincing. The recovery of the analytes in both human plasma and rat plasma was acceptable over the linear range (0.500–50.0 μg/ml for caffeine and 0.0100–1.00 μg/ml for three metabolites). The method was successfully applied in 118 samples from 74 preterm infants with apnea of prematurity. The rat plasma or ultrapure water as a surrogate matrix is worthy of recommendation for routine therapeutic drug monitoring of caffeine.
An association between cancer type and delirium incidence in Japanese elderly patients: A retrospective longitudinal study
Authors: Yamato Kentaro , Ikeda Ai , Endo Motoki , Filomeno Ronald , Kiyohara Kosuke , Inada Ken , Nishimura Katsuji , Tanigawa Takeshi
Published: July 2022

Objective

There is not a known elevated prevalence of delirium in older adult cancer patients. However, it is unknown if the incidence of delirium varies by cancer type among older adult patients. Therefore, this study aimed to examine the association between the incidence of delirium and cancer type among older adult patients using a Japanese hospital‐based administrative claims database.

Methods

A total of 76,868 patients over 65 years of age or older, first diagnosed with cancer on an initial date of hospitalization between April 2008 and December 2019, were included in this retrospective longitudinal study. Delirium was defined by the World Health Organization's International Statistical Classification of Diseases and Related Health Problems (ICD‐10) codes or antipsychotic medication use. Cox proportional hazard models were performed to estimate the risk of delirium incidence according to 22 cancer types during the one‐year hospitalization period.

Results

The incidence rates of delirium were 17.1% for men and 15.3% for women. Compared to gastric cancer, the risk of delirium was significantly higher for pancreatic cancer (HR: 1.26, 95% CI: 1.11–1.42 for men; HR: 1.27, 95% CI: 1.11–1.45 for women), leukemia (HR: 1.24, 95% CI: 1.09–1.41 for men; HR: 1.20, 95% CI: 1.03–1.41 for women), and oropharyngeal cancer (HR: 1.30, 95% CI: 1.10–1.54 for men; HR: 1.32; 95% CI: 1.02–1.72 for women) after adjusting for age, initial hospitalization year, antipsychotic medications, and surgery.

Conclusions

As compared to gastric cancer, patients with pancreatic cancer, leukemia, oropharyngeal cancer were found to have a higher risk of developing delirium. Our study findings suggested that the risk of delirium incidence may vary by cancer type.
Assessment of neoadjuvant chemotherapy with docetaxel, cisplatin, and fluorouracil in patients with oral cavity cancer
Authors: Fu Jin Ye , Yue Xiu Hui , Dong Min Jun , Li Jiang , Zhang Chen Ping
Published: July 2022

Background

Chemotherapy with docetaxel, cisplatin, and fluorouracil (TPF) has been studied in patients with head and neck cancer. Its impact on patients with oral cavity cancer was not specified.

Methods

We consecutively reviewed medical files of patients with untreated oral cavity cancer who received neoadjuvant TPF chemotherapy in our department from January 2017 to April 2020. Outcomes included the objective response to TPF chemotherapy, factors associated with the response, and progression and survival in different response groups.

Results

A total of 167 patients were included, with half of stage IV disease. Complete or partial response was observed in 51 patients. A total of 91 patients had stable disease, and 25 patients had progressive disease. The response was not associated with age, sex, anatomic subsite, and the tumor's T stage. It was related with N stage (p < 0.001) and clinical stage (p = 0.004). Most patients with bulky nodes or nodes with obvious necrosis showed low response or even progressed after neoadjuvant TPF chemotherapy. The planned surgery was conducted in 159 patients. Disease relapse mostly occurred in 2 years after treatment. The 2‐year overall survival and the progression‐free survival were 89.0% and 85.2% for patients with complete or partial response, 62.4% and 55.6% for patients with stable disease, and 12.5% and 4.2% for patients with progressive disease, respectively.

Conclusions

The response of neoadjuvant TPF chemotherapy in patients with oral cavity cancer is related to disease stage, especially the nodal stage. Patients with complete or partial response developed less progression events and better survival.