bluuebunny/crossref_metadata_2025 huggingface dataset:
Sex and Racial and Ethnic Diversity Among Ophthalmology Subspecialty Fellowship Applicants
Authors: Ali Muhammad , Menard Maylander , Zafar Sidra , Williams Basil K. , Knight O’Rese J. , Woreta Fasika A.
Published: August 2023

Importance

Physician-patient concordance in sex and race is associated with improved patient outcomes. Studies have explored diversity among ophthalmology residents and faculty, but to our knowledge, not among ophthalmology fellows.

Objective

To assess diversity by sex and race and ethnicity among fellowship applicants in ophthalmology subspecialties and compare match rates by applicants’ sex and underrepresented in medicine (URiM) status.

Design, Setting, and Participants

This cohort study examined ophthalmology subspecialty fellowship data from the 2021 San Francisco Match.

Main Outcomes and Measures

Applicant characteristics were stratified by sex and URiM status and compared using χ2, Mann-Whitney U, and median tests. For applicants who matched, the percentages of female and URiM applicants were compared among the ophthalmic subspecialties. A multivariable logistic regression model was used to assess the association of applicant characteristics with their match outcomes.

Results

Included in the sample were 537 candidates who applied for an ophthalmology fellowship using the 2021 San Francisco Match; 224 applicants (42.6%) were female, and 60 applicants (12.9%) had URiM status. Females and males had similar match rates (70.5% [n = 158] and 69.2% [n = 209], respectively; P = .74), but females had a higher median (IQR) US Medical Licensing Examination (USMLE) Step 2 Clinical Knowledge (CK) score (248 [240-258] vs 245 [234-254]; P = .01). The pediatric ophthalmology subspecialty had the highest percentage of female matched applicants (67.5%; 27 of 40 matched applicants), while the retina subspecialty had the highest percentage of males (68.9%; 84 of 122 matched applicants). URiM applicants had lower match rates (55.0%, n = 33) than non-URiM applicants (72.2%, n = 293; P = .007). The URiM applicants had lower median (IQR) scores on the USMLE Step 1 (238 [227-247]) compared with Asian applicants (246 [235-254]) and White applicants (243 [231-252]; P = .04). Additionally, URIM applicants submitted fewer median (IQR) applications (10 [1-23]) than Asian (21 [8-37]) and White (17 [8-32]; P = .001) applicants and completed fewer interviews (median [IQR], 2 [0-11]) than Asian (median [IQR], 12 [3-18]) and White applicants (median [IQR], 8 [1-14]; P = .001). Among matched fellows in each subspecialty, URiM applicants comprised 13.9% (n = 11) in glaucoma, 10% (n = 4) in pediatric ophthalmology, 7.3% (n = 6) in cornea, and 6.6% (n = 8) in retina.

Conclusions and Relevance

Ophthalmology subspecialty fellowship match rates were lower for URiM vs non-URiM applicants in 2021. Underrepresentation of females exists in the retina subspecialty, while racial and ethnic differences exist in all ophthalmology subspecialty fellowships examined. Monitoring trends in fellowship diversity over time should help inform where targeted efforts could improve diversity.
YTnC2, an improved genetically encoded green calcium indicator based on toadfish troponin C
Authors: Subach Oksana M. , Vlaskina Anna V. , Agapova Yulia K. , Nikolaeva Alena Y. , Varizhuk Anna M. , Podgorny Oleg V. , Piatkevich Kiryl D. , Patrushev Maxim V. , Boyko Konstantin M. , Subach Fedor V.
Published: August 2023

Genetically encoded calcium indicators based on truncated troponin C are attractive probes for calcium imaging due to their relatively small molecular size and twofold reduced calcium ion buffering. However, the best‐suited members of this family, YTnC and cNTnC, suffer from low molecular brightness, limited dynamic range, and/or poor sensitivity to calcium transients in neurons. To overcome these limitations, we developed an enhanced version of YTnC, named YTnC2. Compared with YTnC, YTnC2 had 5.7‐fold higher molecular brightness and 6.4‐fold increased dynamic range in vitro. YTnC2 was successfully used to reveal calcium transients in the cytosol and in the lumen of mitochondria of both mammalian cells and cultured neurons. Finally, we obtained and analyzed the crystal structure of the fluorescent domain of the YTnC2 mutant.
Exposed Agency: Poetic Architectural Projection Across and Between Disciplines
Authors: Robbins Felix
Published: August 2023

The combination of an understanding of architectural history and a compositionally advanced architectural ‘eye’, integrated with a PhD in second‐order cybernetics, has shaped the preoccupations of architect Felix Robbins's work. Here he describes his architectural world and his ongoing projected speculations within it.
The Artist as Contemporary Philanthropist
Authors: Battista Kathy
Published: August 2023

Artists can have a remarkable impact on the rejuvenation of city districts and blocks, both through their own presence and through community artistic engagement. American writer and curator Kathy Battista shows us a number of ways this type of engagement has helped in differing areas of the US, and the creative and social benefits it has brought with it.
Linking Interfacial Hydrogen‐Bond Network to Electrochemical Performance of Zinc Anode in Aqueous Solution
Authors: Zhang Jie , Li Pengfei , Wang Yujie , Zhao Zhiwei , Peng Zhangquan
Published: August 2023

Water‐induced parasitic reaction, e.g., spontaneous corrosion and hydrogen evolution reaction, has been widely recognized as a culprit of the poor electrochemical performance of Zn anode in aqueous electrolyte. Nevertheless, how the interfacial water, the pertinent participant of the Zn electrochemistry, affects the parasitic reaction occurring on Zn anode remains incompletely understood. Herein, a step forward toward understanding the relationship of the hydrogen‐bond network of interfacial water and the electrochemical performance of Zn anode is reported, where the structure of interfacial water can be regulated by (aminomethyl)phosphonic acid (AMPA), a molecular additive that can specifically adsorb on Zn surface. Direct spectral evidence coupled with theoretical calculation reveals that the AMPA preferentially adsorbs on the Zn anode surface that serves as a shield for water dissociation (i.e., spontaneous corrosion). Moreover, AMPA can promote interfacial water toward ordered H‐bond network with high electrochemical stability at electrified interface. As a result, water‐induced parasitic reaction has been significantly suppressed, enabling a dendrite‐free Zn2+ deposition, an exceptional high coulombic efficiency, prolonged longevity of model Zn/Zn cells, and improved Zn//NH4V4O10 full battery. The results presented here underscore the ramifications of interfacial water structure and provide design criteria for versatile electrolytes of rechargeable Zn batteries.
Unraveling New Role of Binder Functional Group as a Probe to Detect Dynamic Lithium‐Ion De‐Solvation Process toward High Electrode Performances
Authors: Wang Yuqi , Ma Zheng , Cao Zhen , Cai Tao , Liu Gang , Cheng Haoran , Zhao Fei , Cavallo Luigi , Li Qian , Ming Jun
Published: August 2023

Binder plays a pivotal role in the development of lithium‐ion batteries as it must be used to adhere electrode materials on current collectors tightly to guarantee stability. Then, many binder molecules have been designed to enhance the adhesion capability, and conductivity, and/or form a robust solid electrolyte interphase layer for better performance. However, the binder effect on the lithium‐ion (i.e., Li+) de‐solvation on the electrode surface has never been reported before. Herein, it is reported that the binder can influence the Li+ (de‐)solvation process significantly, where its functional group can serve as a probe to detect the dynamic Li+ (de‐)solvation process. It is discovered that different binder functional groups (e.g., *─COO− versus *─F) can affect the Li+‐solvent arrangement on the electrode surface, leading to different degrees of side‐reactions, rate capabilities, and/or the tolerance against Li+‐solvent co‐insertion for the graphite anode, such as in the propylene carbonate‐based electrolyte. A molecular interfacial model related to the electrolyte component's behaviors and binder functional group is proposed to interpret the varied electrode performance. This discovery opens a new avenue for studying the interactions between the binder and electrolyte solvation structure, in turn helping to understand electrode performances underlying the micro‐structures.
Defect Dipole‐Induced Fatigue Strain Recoverability in Lead‐Free Piezoelectric Ceramics
Authors: Wang Binquan , Huangfu Geng , Wang Jie , Li Hua , Guo Yiping
Published: August 2023

Piezoelectric ceramics have garnered extensive utilization in high‐precision actuators, where the magnitude of electric field‐induced strain and fatigue resistance play crucial roles in actuation applications. Herein, an innovative strategy based on defect dipoles is proposed to form a defect‐engineered polymorphic phase transition and achieve a giant piezoelectric strain coefficient of 3080 pm V−1 in Li/Sr‐doped (K0.5Na0.5)NbO3 lead‐free piezoceramics. The mechanism responsible for the enhanced strain performance lies in the optimized strain compatibility between the refined stripe domains and the nanosized domains. Additionally, the results demonstrate that the material is able to recover from fatigue‐induced strain depletion under the stimulation of bipolar electric fields. This property can be phenomenologically explained by the rigid ion model, in which the application of reversal electric fields can facilitate the restoration of defect dipoles, thereby greatly contributing to strain recoverability. This study establishes a close correlation between the unipolar strain properties and the inherent flexibility of defect dipoles and provides new insight into the design of high‐reliability, large‐stroke piezoceramics.
Solar‐Powered High‐Performance Lignin‐Wood Evaporator for Solar Steam Generation
Authors: Gu Yuanjie , Wang Danning , Gao Ying , Yue Yiying , Yang Weisheng , Mei Changtong , Xu Xinwu , Xu Yong , Xiao Huining , Han Jingquan
Published: August 2023

Recent research on wood‐based solar evaporators has made great progress and significant breakthroughs have been made in using lignin as a photothermal material; however, the intensity change mechanism regarding the conjugate structure of lignin is almost never mentioned. This study innovatively proposes a mechanism to explain the changes in conjugate intensity that occur before and after lignin dissolution and fabricates a lignin/wood‐based solar evaporator (LWE) using an all‐wood‐based material that is salt‐tolerant and has long‐term serviceability. Lignin in the evaporator serves not only as a photothermal material for converting light energy into heat energy but also as a reinforcement for the evaporator's structural strength. Adding lignin changes the original structure of balsa wood, increasing the proportion of intermediate water in the LWE, thereby lowering the enthalpy of water evaporation. The optimized LWE with an enhanced desalination capability, dye removal property, and high stability exhibits full‐spectrum solar absorption of about 83.6%, a photothermal conversion efficiency of 91.74%, and an evaporation efficiency of 1.93 kg m−2 h−1, which surpasses most wood‐based evaporators. This study demonstrates that all‐wood‐based materials can be used to prepare evaporators with excellent performance, providing a new approach to address freshwater depletion.
Transparent, Flexible, and Highly Sensitive Piezocomposite Capable of Harvesting and Monitoring Kinetic Movements of Microbubbles in Liquid
Authors: Choi Daekyu , Jo Hongseok , Yoon Taegeun , Park Dogun , Kim Kiyong , Kim Yong Il , Song Young Jae , Yoon Sam S. , An Seongpil
Published: August 2023

In this study, a zinc oxide (ZnO)‐decorated nickel microfiber (ZNMF)‐based piezoelectric nanogenerator (ZNMF‐PENG) using electrospinning, metal electroplating, electrospraying, and ceramic growing techniques is fabricated. The combination of these techniques enables the ZNMF‐PENG to possess high transparency and flexibility that are difficult to achieve through the existing piezoceramic‐based PENGs. In particular, the presence of innumerable piezoceramic ZnO nanowires inside the ZNMF‐PENG allows for detecting microbubble movements having an extremely low buoyancy force of 0.009 N, which is beneficial for detecting cavitation. Moreover, in comparison to previously reported PENGs fabricated using an electrospinning technique, the ZNMF‐PENG demonstrates the highest energy‐harvesting efficiency of 8750 V N−1 m−2. The novel approach in materials and methods proposed in this study is expected to contribute to the further advancement in developing transparent, flexible, and performance‐improved PENGs applicable to various industrial applications.
Integrating Liquification of the Gelated Tumor Interstitium around Nanomedicines with Biconditional GD2‐Targeting for Precise and Safe Chemotherapy
Authors: Xue Weili , Lin Xiaowei , Xu Liangbo , Trital Ashish , He Yi , Tang Guping , Bai Hongzhen , Chen Shengfu
Published: August 2023

The quick diffusion of nanomedicines in the polysaccharide‐gel‐filling tumor interstitium and precise active targeting are two major obstacles that have not yet been overcome. Here, a poly(L‐glutamyl‐L‐lysine(EK) (p(EK))‐camouflaged, doxorubicin (Dox)‐conjugated nanomedicine is developed to demonstrate the underlying mechanism of zwitterionic shell in synchronous barrier‐penetration and biconditional active targeting. The zwitterionic p(EK) shell liquifies its surrounding water molecules in the polysaccharide gel of tumor interstitium, leading to five times faster diffusion than the pegylated Doxil with similar size in tumor tissue. Its doped sulfonate groups lead to more precise active tumor‐targeting than disialoganglioside (GD2) antibody by meeting the dual requirements of tumor microenvironment (TME) pH and overexpression of GD2 on tumor. Consequently, the concentrations of the nanomedicine in tumor are always higher than in life‐supported organs in whole accumulation process, reaching over ten times higher Dox in GD2‐overexpressing MCF‐7 tumors than in life‐supporting organs. Furthermore, the nanomedicine also avoids anti‐GD2‐like accumulation in GD2‐expressing kidney in a mouse model. Thus, the nanomedicine expands the therapeutic window of Doxil by more than three times and eliminates tumors with negligible myocardial and acute toxicity. This new insight paves an avenue to design nanodelivery systems for highly precise and safe chemotherapy.
In Situ Controlled Growth of Strongly Quantum Confined CsPbBr3/FAPbBr3 Core/Crown Nanoplatelets for Blue Light Emitting Diodes
Authors: Kshirsagar Anuraj S , Gangishetty Mahesh K
Published: August 2023

A few unit cells of thick colloidal CsPbBr3 nanoplatelets (NPLs) exhibit strong quantum confinement. However, due to the increased surface‐to‐volume ratio, they show poor photoluminescence quantum yield (PLQY) resulting from surface traps. Here, a unique, quantum‐confined core/crown perovskite is reported for the first time, where the CsPbBr3 NPL surface is passivated by laterally grown thin FAPbBr3 crown layers. Unlike regular core/shells, the FAPbBr3 is coated around the core NPLs resulting in blue emission. Careful control of the growth kinetics while monitoring growth using in situ PL led to the formation of core/crown perovskites with nearly two times improvement in thin film PLQYs. HR‐TEM analyses show that the interplanar distances of the core match with CsPbBr3 and the crown match with FAPbBr3. The XRD and TEM analyses revealed that their thickness remains the same even if Cs+ to FA+ ratios are varied, indicating lateral growth of FAPbBr3 around the CsPbBr3 core. Further, FA+ ions in the crown lattice are confirmed by FTIR and 1HNMR. Finally, considering their high PLQYs and narrow linewidths, the core/crown NPLs are employed as blue emitters in light‐emitting diodes, and a maximum external quantum efficiency of 0.4% at 2.71 eV (457 nm) with a luminance of 513 cd m−2 is achieved.
Biosynthesis of High‐Active Hemoproteins by the Efficient Heme‐SupplyPichia PastorisChassis
Authors: Yu Fei , Zhao Xinrui , Zhou Jingwen , Lu Wei , Li Jianghua , Chen Jian , Du Guocheng
Published: August 2023

Microbial synthesis of valuable hemoproteins has become a popular research topic, andPichia pastorisis a versatile platform for the industrial production of recombinant proteins. However, the inadequate supply of heme limits the synthesis of high‐active hemoproteins. Here a strategy for enhancing intracellular heme biosynthesis to improve the titers and functional activities of hemoproteins is reported. After selecting a suitable expressional strategy for globins, the efficient heme‐supplyP. pastorischassis is established by removing the spatial segregation during heme biosynthesis, optimizing precursor synthesis, assembling rate‐limiting enzymes using protein scaffolds, and inhibiting heme degradation. This robust chassis produces several highly active hemoproteins, including porcine myoglobin, soy hemoglobin,Vitreoscillahemoglobin, and P450‐BM3, which can be used in the development of artificial meat, high‐cell‐density fermentation, and whole‐cell catalytic synthesis of high‐value‐added compounds. Furthermore, the engineered chassis strain has great potential for producing and applying other hemoproteins with high activities in various fields.
Semiconductor Wafer Bonding for Solar Cell Applications: A Review
Authors: Tanabe Katsuaki
Published: August 2023

Wafer bonding is a highly effective technique for integrating dissimilar semiconductor materials while suppressing the generation of crystalline defects that commonly occur during heteroepitaxial growth. This method is successfully applied to produce efficient solar cells, making it an important area of research for photovoltaic devices. In this article, a comprehensive review of semiconductor wafer‐bonding technologies is provided, focusing on their applications in solar cells. Beginning with an explanation of the thermodynamics of wafer bonding relative to heteroepitaxy, the functionalities and advantages of semiconductor wafer bonding are discussed. An overview of the history and recent developments in high‐efficiency multijunction solar cells using wafer bonding is also provided. Bonded solar cells made of various semiconductor materials are reviewed and various types of wafer‐bonding methods, including direct bonding and interlayer‐mediated bonding, are described. Additionally, other technologies that utilize wafer bonding, such as flexible cells, thin‐film transfer, and wafer reuse techniques, are covered.
Machine Learning Accelerated Prediction of Self‐Trapped Excitons in Double Halide Perovskites
Authors: Chen Baian , Chen Rui , Huang Bolong
Published: August 2023

Broadband emission induced by self‐trapped excitons (STEs) in double halide perovskites (DHPs) has received continuous attention in recent years. However, the comprehensive understanding of the STEs formation mechanism is still in its early stage. The corresponding roles of different B‐site cations also remain unclear in these advanced materials. The lack of an effective STEs database for DHPs hinders the efficient discovery of potential optoelectronic materials with strong STEs. Herein, a systematic STEs database is built for DHPs through density functional theory (DFT) calculations and proposed a highly efficient predictive machine learning (ML) model of the Huang–Rhys factor S for the first time. Results reveal the different contributions of two B‐site metal cations to the formation of STEs in DHPs, which helps to understand the in‐depth nature of STEs. Based on the accurate predictions of the effective phonon frequency ω
, it is further realized that the prediction of S without conducting the time‐consuming phonon property calculations of DHPs offers new opportunities for exploring the STEs. Combining DFT calculations and ML techniques, this study supplies an effective approach to efficiently discover the potential novel optoelectronic materials, which provides important guidance for the future exploration of promising solid‐state phosphors.
A Physical Description of the Variability in Single‐ReRAM Devices and Hardware‐Based Neuronal Networks
Authors: Funck Carsten , Wiefels Stefan , Bengel Christopher , Schnieders Kristoffer , Hoffmann-Eifert Susanne , Dittmann Regina , Menzel Stephan
Published: August 2023

Resistive switching devices are candidates to be used as weight for the future hardware realization of neuronal networks. Herein, these resistive switches base on oxygen vacancy migration and can be toggled between different resistance states. Internal processes lead to a variability over time in these states. To understand this, a dynamical model is developed, which links the internal physical mechanism to the current response. Thereby, the electronic current is calculated by tunneling processes over oxygen vacancies. The model allows to understand the physical transport properties and the current–voltage dependence. Integrating ionic hopping processes clarifies the variability in the electronic conduction. The derived model does not require empirical input parameters and only depends on the properties of the materials. This allows to use literature values and independently compare them to electrical measurements. The model predicts the experiments correctly. Thereupon, the physical properties of the conduction are investigated with respect to the transport over discrete energy levels, which change under the hopping of oxygen vacancies. Afterwards, the current level and variability are simulated for increasing oxygen vacancy concentrations to investigate analog switching, which is required for neuronal network layers. Finally, the variability is tested with multiple interacting cells in a neuronal layer.
Intelligent Gripper Systems Using Air Gap‐Controlled Bimodal Tactile Sensors for Deformable Object Classification
Authors: Min Yulim , Kim Yunjeong , Jin Hanbit , Kim Hye Jin
Published: August 2023

Multimodal tactile sensors have played an important role in enhancing robot intelligence by providing reliable datasets originating from their high accuracy and durability characteristics. Herein, bimodal tactile sensors capable of simultaneously recognizing the size and stiffness of grasped objects, even deformable ones, are produced. The bimodal tactile sensors are fabricated using the identical process of controlling the air gap between a flexible substrate and the sensing layer, allowing the sensorized gripper to measure pressure and bending characteristics with high accuracy and durability. The pressure sensor yields an excellent durability performance with a negligible change of ΔI/I
o < 4.01% even after more than 104 pressing–releasing cycles and broad detection range (5–360 kPa) characteristics. The bending strain sensor also exhibits high sensitivity in a broad bending strain range (0–2.3%) and high durability with a change of ΔI/I
o < 4.48% for 104 bending cycles. Using these devices, the sensorized gripper demonstrates that seven tomatoes with different sizes and ripeness states can be classified with high accuracy of 98.78% using an artificial neural network. Finally, the tactile feedback system is expected to be utilized in smart factories, automation systems, and humanoid robots in the near future.
Ion Migration‐Modulated Flexible MXene Synapse for Biomimetic Multimode Afferent Nervous System: Material and Motion Cognition
Authors: Ren Shuhui , Wang Kaiyang , Jia Yunfang , Yan Xiaobing
Published: August 2023

The biomimetic afferent nervous system (ANS) is significant for transporting external stimuli into intelligent robots; however, it is still far from bionics due to traditional multisensor and single‐cognition strategies. Herein, a flexible biomimetic ANS with multimode fuzzy perception and brain‐like cognition is developed, by fusing the ion migration‐modulated MXene synapse and machine learning (ML). First of all, the elementary perceptual ability to mimic biological neuroreceptors is demonstrated. Motion artifact in the ionic conductive elastomer (ICE) current is eliminated. Furthermore, the multimode perception and brain‐like cognition are accomplished by synaptic currents (SCs) and nine ML algorithms. Finally, the cognitions of materials, gestures, and motions are conducted by distributing the ANS devices across body joints, and with the optimal ML method, the accuracies can reach 80%, 100%, and 90%, respectively. This synapse‐based ANS may provide a new idea for developing next‐generation neuromorphic intelligent robots.
Controllable One‐Step Assembly of Uniform Liquid Crystalline Block Copolymer Cylindrical Micelles by a Tailored Nucleation‐Growth Process and Their Application as Tougheners
Authors: Hu Lingjuan , Li Qin , Luo Yunjun , Jin Bixin , Chi Shumeng , Li Xiaoyu
Published: August 2023

The fabrication of uniform cylindrical nanoobjects from soft materials has attracted tremendous research attention from both fundamental research and practical application points of view but has also posed outstanding challenges in terms of their preparation. Herein, we report a one‐step method to assemble cylindrical micelles (CMs) with highly controllable lengths from a single liquid crystalline block copolymer by an in situ nucleation‐growth strategy. By adjusting the assembly conditions, the lengths of the CMs are controlled from hundreds of nanometers to micrometers. Several influencing factors are systematically investigated to comprehensively understand the process. Particularly, the solvent quality is found determinative in either enhancing or suppressing the nucleation process to produce shorter and longer CMs, respectively. Taking advantage of this strategy, the lengths of CMs can be nicely controlled over a wide concentration range of four orders of magnitude. Lastly, CMs are produced on decent scales and applied as additives to dramatically toughen glassy plastic matrix, revealing an unprecedented length‐dependent toughening effect.
La metafora: the power of metaphors and creative resources in working systemically with families and children with autism—a conversation with Carmine Saccu
Authors: Amorin‐Woods Deisy , Saccu Carmine
Published: August 2023

Metaphors are valuable tools of expression, which give meaning to situations and allow the spontaneous processing of feelings and emotions. As therapists, we can support clients to develop and create their individual metaphor to explain their own meaning of experiences or communicate their perception of problems. Creativity provides us with a rich landscape to explore, expand, and enrich ourselves as therapists and consequently our clients. As systemic therapists, we are responsible for the co‐creation of a human process, which has at its core safety in allowing expression, connection, and movement. Through a respectful and curious approach, we can develop pathways to tap organically into our ‘creative selves’ while reaching into our clients' creativity and selves as catalysts for connection and positive change. Creative resources and therapies have been successfully used in psychotherapy to enhance the mental and emotional well‐being of children, particularly children with autism who have limited verbal capacity or who are non‐verbal. These children also wish to be understood in expressing their thoughts and feelings; however, they use other methods of communication – sometimes obvious, sometimes not. Therefore, it is important that a therapist can access diverse ways to support the child through this process. The creative use of animals in therapy neutralises spaces, eliciting calm, safety, and healing. This is particularly the case when working with this group of children. This paper is derived from my conversation with an elder statesman of the family therapy profession, Professor Carmine Saccu. He is a jovial master storyteller who craftfully communicates via metaphors. Through creative means, play, and humour, he has developed a remarkably unique way of working with children, especially non‐verbal children with autism. He uses his canine, co‐therapist Mafalda, as a powerful resource and intervention strategy to safely elicit engagement and connection in the therapeutic space.
PolyVinyl alcohol and copper nickel co‐doped titania nanocomposite: Designing, characterization, optical properties, and catalytic application in the synthesis of aryl derivatives of benzothiazole and benzimidazole
Authors: Mahajan Ankush , Gupta Monika
Published: August 2023

The paper examines the properties and potential applications of a nanocomposite material composed of polyvinyl alcohol (PVA) and copper nickel co‐doped titanium dioxide (Cu‐TiO2‐Ni). The material was synthesized using a simple precipitation process, and its properties were characterized using various analytical techniques, including powder X‐ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry analysis, field emission scanning electron microscopy, and high‐resolution tunnelling electron microscopy; Brunauer–Emmett–Teller (BET) surface area was investigated. The results showed that the addition of Cu‐TiO2‐Ni to PVA improved the material's Ultraviolet–visible spectroscopy (UV) absorption properties. Additionally, the PVA/Cu‐TiO2‐Ni nanocomposite material exhibited potential for use in a range of applications, including catalysis. Its utility in synthesizing aryl derivatives of benzothiazole and benzimidazoles, which are crucial intermediates in the fine chemical, agrochemical, and pharmaceutical industries and material science, was evaluated. It was found to offer several advantages, including a quick reaction time, simple workup, and good to excellent isolated yields. These characteristics make this protocol both practical and economically intriguing.
Proactively Stress‐Testing Water Treatment Facilities for Harmful Algal Blooms
Authors: Sajdak Nichole , Charles Gail
Published: August 2023

Key Takeaways

A user‐friendly, Excel‐based tool was used to understand how existing water treatment processes handle cyanotoxins and to modify standard operating procedures to improve performance.

Water treatment plants should understand the full capabilities of contact time throughout the treatment train in the event they must remove extracellular (dissolved) cyanotoxins.

Utilities at risk for cyanotoxin events could benefit from using existing chlorination facilities as a tool to treat extracellular cyanotoxins in certain situations.
Berechnungen der Van Der Waalsschen Konstanten A und B.
Authors: Hers W.
Published: August 2023

Breslau, Physikalisch‐Chemische Abteilung der Universität, den 4. März 1920.
Über die Reaktion zwischen Ferrisalz und schwefliger Säure und ihre Katalysierung
Authors: Pinnow Joh.
Published: August 2023

1. Bei der Reaktion zwischen Ferrisalz und Sulfit ist für die Dithionatbildung günstig niedrige Wasserstoffionenkonzentration.

2. Chinon und Hydrochinon sowie deren Sulfosäuren wirken als Übertragungskatalysator und fördern die Oxydation des Sulfits durch Ferrisalz zu Sulfat. Vermehrung des Katalysators steigert seine Wirkung.

3. In an sich saurer Lösung tritt gemäß Satz I die Wirkung des Katalysators weniger hervor.

4. Die verstärkte Sulfatbildung aus Sulfit und Ferrisalz bei Gegenwart von Chinon spricht gegen die Auffassung von Mees und Sheppard, daß aus Chinon und Sulfit sich Dithionat bilde.

5. Chinon geht bei der Reaktion in Sulfosäure über.

6. Regenerierung des Hydrochinons bzw. seiner Sulfosäuren durch schweflige Säure und neue Oxydation zu Chinon läßt sich nicht in den diese Substanzen enthaltenden photographischen Entwicklerlösungen, die bekanntlich alkalisch reagieren, sondern nur in saurer Lösung realisieren.

7. Die katalytische Wirkung des Chinons läßt sich durch Farbenwechsel demonstrieren.

8. Hydrochinonsulfosäure verbraucht in 0,025 molarer Schwefelsäure auch bei Rücktitration nur sehr geringe Mengen Jodlösung.
Die elektrochemische Spannungsreihe der Sulfide
Authors: Noddack Iv. , Wrabetz K. , Herbst W.
Published: August 2023

Es wird versucht, die Ergebnisse stromloser Spannungsmessungen an galvanischen Zellen mit Sulfidelektroden durch Aufstellung einer praktischen Spannungsreihe der elektrisch leitenden Sulfide auszuwerten. Einige Nebenerscheinungen (Einfluß des Luftsauerstoffs, motoelektrische Effekte usw.), die bei den Messungen beobachtet wurden, sowie einige Vorstellungen über die ablaufenden elektrochemischen Prozesse werden erörtert.
Grundlagen und Anwendungsbeispiele neuer Meßanordnungen der Überspannungen
Authors: Piontelli R.
Published: August 2023

Das Studium der Kinetik elektrochemischer Prozesse, insbesondere den Einfluß der Elektrodenmaterialien oder die Abänderungen der Materialien selbst betreffend, kann mit den klassischen Methoden unter den verschiedensten Bedingungen durchgeführt werden, soweit die Form der Zellen, die Art der Sonden, die Speise‐ und Meßbedingungen nach bestimmten Grundsätzen ausgebildet sind. Es werden die wichtigsten Merkmale der in Mailand zur Anwendung kommenden Vorrichtungen besprochen und einige praktische Beispiele wiedergegeben.
Einleitung von Polymerisationsreaktionen durch atomaren Wasserstoff. I
Authors: Beckey H.‐D. , Groth W.
Published: August 2023

Atomarer Wasserstoff aus einer Glimmentladung wurde in stark abgekühlte Monomerenflüssigkeiten (Vinylverbindungen, Diene) geleitet, die bei Zimmertemperatur einen erheblichen Dampfdruck besitzen (Versuchsmethode I); oder atomarer Wasserstoff wurde in der Gasphase mit Vinylverbindungen und Dienen zur Reaktion gebracht, die Reaktionsprodukte bei tiefer Temperatur kondensiert und anschließend Monomeres hinzudestilliert (Versuchsmethode II). Nach Beendigung der Reaktion des atomaren Wasserstoffs mit Acrylsäureestern und nach Erwärmung des Reaktionsgemisches auf 30,5°C wurde eine lange Nachpolymerisationsperiode gefunden. Hieraus wird geschlossen, daß außer der üblicherweise angenommenen Radikalbildung durch Aufspaltung der Äthylendoppelbindung durch atomaren Wasserstoff auch eine langlebige, kettenauslösende Beschleunigersubstanz gebildet wird. Die Halbwertszeit für die Abnahme des Beschleunigers wurde beim Acrylsäuremethylester bestimmt (8 min bei 30,5°C) und die Abhängigkeit der Polymerisationsgeschwindigkeit von der Reaktionszeit des atomaren Wasserstoffs gemessen. Die übrigen untersuchten Vinylverbindungen und Diene zeigten keine meßbare Nachpolymerisation.
Über die Druckzerstörung der Kristallphosphore
Authors: Meier Hans
Published: August 2023

Die Verminderung des Leuchtvermögens anorganischer Phosphore durch Zerreiben ist schon lange bekannt. Man schrieb dies teilweise eher einer starken Änderung der Streuung des erregenden Lichtes zu als einer wahren Druckzerstörung, d.h. einer Wirkung auf den Leuchtmechanismus selbst.

Zur Aufklärung des Zerstörungsmechanismus wurde an einer Reihe von Kristallphosphoren [ZnS · Cu, (ZnCd)S · Ag; Cu u. a.] durch hohen mechanischen Druck das m‐und d‐Leuchten weitgehend vernichtet und der innere lichtelektrische Effekt sowie die Änderung der Dielektrizitätskonstante im Licht von unzerstörtem und zerstörtem phosphor verglichen.
Über CH3‐Gruppen‐ und Hauptkettenbeweglichkeit im Polymethacrylsäuremethylester
Authors: Kosfeld R. , Vosskötter G.
Published: August 2023

Bei Vinylpolymerisaten wie z.B. Polystyrol, Polyvinylacetat, Polyvinylchorid, Poly‐α‐methylstyrol, Polyacrylsäuremethylester, Poly‐α‐Chloracrylsäuremethylester und Polystyrol findet man für den Glaszustand Halbwertsbreiten zwischen 9 und 11 Gauß. Nur Polymethacrylsäuremethylester (PMMA) zeigt fär den Glaszustand eine Halbwertsbreite von etwa 4,2 Gauß. Durch Lösungsmittelzugabe war es möglich, auch beim PMMA eine zweite Absorptionslinie mit einer Halbwertsbreite von etwa 8 Gauß neben derjenigen von 4,2 Gauß zu beobachten. Es wird gezeigt, daß durch die breite Absorptionslinie der Glaszustand beim PMMA wiedergegeben wird.
Über das dielektrische Verhalten von Epoxydharzen
Authors: Kobale M. , Löbl H.
Published: August 2023

Messungen der dielektrischen Eigenschaften von Epoxydharzen im Frequenzbereich zwischen 30 Hz und 1010 Hz lassen zwei charakteristische, mit dem molekularen Aufbau der Epoxydharze verbundene Dispersionsgebiete erkennen. Vor allem das auf Kettenbeweglichkeit zurückgehende Verlustmaximum wird, wie Variationen der Aushärtebedingungen und der Härtermengen ergaben, vom Vernetzungsgrad des Stoffes stark beeinflußt. Der Verlauf der Aushärtereaktion läßt sich unmittelbar durch dielektrische Messungen verfolgen.

Die aus der Temperatur‐Frequenzverschiebung der Verlustfaktormaxima errechneten Aktivierungsgrößen (Enthalpie und Entropie) ermöglichen eine quantitative Beurteilung des Vernetzungsgrades. Die Störung des Stoffgefüges, welche durch die Umorientierung beweglicher Dipole im elektrischen Feld verursacht wird, nimmt, wenn man von der Harzkomponente allein ausgeht, mit zunehmendem Härterzusatz ab. Erst bei Einbau von mehr als der halben stöchiometrischen Härtermenge läßt ein Anstieg der Aktivierungsgrößen mit wachsendem Härterzusatz eine zunehmende Behinderung der Dipolbeweglichkeit erkennen. Bei hinreichender Aushärtung zeigt ein Maximalwert der Aktivierungsgrößen den Einbau der stöchiometrischen Härtermenge an.
Zur Theorie des dielektrischen Verhaltens von polaren Hochpolymeren in Lösungen
Authors: Kästner Siegfried
Published: August 2023

In der Arbeit wird zunächst gezeigt, daß die bestehenden Theorien von Kirkwood und Fuoss, Kuhn, Hammerle und Kirkwood, Zimm sowie van Beek und Hermans keine befriedigende Übereinstimmung mit den experimentellen Ergebnissen von Brouckére und Mitarbeitern hinsichtlich des dielektrischen Relaxationsverhaltens der Lösungen von Polymethacrylsäuremethylester und Polyvinylacetat zeigen. Anschließend wird deshalb ein neues statistisches Segmentmodell angegeben, das auf eine bessere Übereinstimmung mit den experimentellen Ergebnissen führt.
Formation Mechanism of Binuclear Ni‐Tartrate Complexes from Relaxation Measurements
Authors: Hoffmann Heinz , Nickel Ulrich
Published: August 2023

The kinetics of the formation and dissociation of Ni complexes of meso‐tartrate, malate and D‐tartrate have been investigated with a pressure jump method. In solutions of Ni‐meso‐tartrate and Ni‐malate only one relaxation time is observed, the concentration dependence of which can be explained by the equilibrium Ni2+ + L2‐ → NiL. The measurements indicate that only one hydroxy group and one carboxylate group of the meso‐tartrate are coordinated in the Ni‐meso‐tartrate complex. The second carboxylate group is also coordinated in the Ni‐malate complex. The rate determining step for the formation of the chelate is the closing of the ring and not the formation of the first bond.

A second relaxation time that is observed in Ni‐D‐tartrate can be explained by assuming a dimerisation reaction according to NiL + NiL → Ni2L2. A structure for the double complex is proposed.
Pulsradiolytische Untersuchung der Reduktion des Ag+‐Ions in ammoniakalischer Lösung
Authors: Pukies J. , Roebke W.
Published: August 2023

Ammoniak beeinflußt mehrere Elementarprozesse der Ag+‐Reduktion in wäßriger Lösung, was auf die Komplexbildung der geladenen Zwischenprodukte zurückgeführt wird. Ag2(am)+ wird im Verlauf der Reaktionen eaq−+ Ag(NH3)2+ → Ag und Ag + Ag(NH3)2(am)+ → Ag2(am)+ wie bei Abwesenheit von Ammoniak gebildet. Ag2(am)+ reagiert mit seinesgleichen bei kleiner und mit Ag(NH3)2+ bei großer Silberkonzentration. Bei beiden Reaktionen entstehen langlebige Komplexe der Reaktanden, deren Zerfall nach erster Ordnung beobachtet werden kann. Ag(NH3)2+ wird durch OH zu Ag(am)2+ oxydiert. Das zweiwertige Silber lebt im Ammoniakkomplex länger als in rein wäßriger Lösung. Als Endprodukt der Reduktion in Gegenwart von Ammoniak entstehen große Silberagglomerate ähnlich wie bei der Reduktion in wäßriger Lösung.
Zur Frage des aromatischen Charakters von 6‐Ring‐Chelaten 1. Die H‐Brücken‐Chelate der 1‐Amino‐3‐imino‐propene [1]
Authors: Daltrozzo E. , Feldmann K.
Published: August 2023

Unter den Chelaten beanspruchen diejenigen 5‐ bzw. 6gliedrigen Typen besonderes Interesse, in denen durch das Vorliegen von 6π‐Elektronen im Chelatring die prinzipielle Möglichkeit zur Ausbildung eines zyklisch konjugierten, also aromatischen, in neuerer Zeit vielfach auch als “nicht klassisch aromatisch” bezeichneten Systems gegeben ist. Seitdem Calvin und Wilson 1945 für die Acetylacetonate zyklische π‐Elektronenkonjugation in Erwägung gezogen haben, wurde für eine Reihe ähnlich gebauter H‐ bzw. Metallchelate aromatische Struktur postuliert. Vorliegende Arbeit zeigt durch Vergleich von UV‐ und NMR‐spektroskopischen Daten der 1‐Amino‐3‐imino‐propene mit denen der entsprechenden zyklisch konjugierten bzw. nicht zyklisch konjugierten Modellverbindungen, daß diesen H‐Chelaten eine nicht zyklisch konjugierte Elektronenstruktur zukommt.
Konformation, übermolekulare Struktur und weitreichende Ordnung in nichtkristallinen und nichtstereospezifischen Polymeren Teil II. Die übermolekulare Struktur von Blockcopolymeren als Folge einer Unverträglichkeit der Sequenzen und der molekularen Konformation
Authors: Krömer H. , Hoffmann M. , Kämpf G.
Published: August 2023

Styrol/Butadien (SB)‐Blockcopolymere sind wegen der Unverträglichkeit der verschiedenartigen Sequenzen entmischt und deshalb mikroheterogen. Die entmischten Bezirke haben kolloidale Abmessungen und enthalten zu mindestens 90% nur eine Sequenzart. Um die Beziehungen zwischen der übermolekularen Struktur und dem Molekülbau zu klären, wurden systematische Untersuchungen an sorgfältig synthetisierten und charakterisierten SB‐Blockcopolymeren vorgenommen (siehe Teil I dieser Veröffentlichung). Die experimentellen Ergebnisse lassen sich theoretisch deuten und führen zu dem Schluß, daß in diesen Blockcopolymeren beide Arten von Sequenzen als statistische Knäuel mit ähnlichen Abmessungen wie in athermischen Lösungen vorliegen. Die übermolekulare Struktur wird in erster Linie durch die Raumerfüllung und gegenseitige Durchdringung solcher Knäuel, weniger durch die Grenzflächenenergie bestimmt. Mit Hilfe dieser Annahmen gelingt es, Abstand, Form und Größe der übermolekularen Aggregate vorauszuberechnen. Die Überlegungen lassen sich verallgemeinern und auch auf andere Blockcopolymere anwenden.
Bestimmung des beweglichen Anteils von Polyäthylenterephthalat mit Hilfe der magnetischen Kernresonanz
Authors: Eichhoff U. , Zachmann H. G.
Published: August 2023

Das Kernresonanzsignal von Polyäthylenterephthalat wird mit Hilfe eines besonderen Verfahrens, bei dem das Spektrum jeweils mehrmals mit verschiedenen Modulationsamplituden aufgenommen wird, in eine breite und eine schmale Komponente aufgespalten. Aus den Flächen unter diesen Komponenten wird der bewegliche Anteil bestimmt, d. h. der Anteil der Segmente, die eine mikrobrownsche Bewegung ausführen. Eine mit Hilfe der Theorie des freien Volumens vorgenommene Extrapolation des beweglichen Anteils auf unendlich hohe Temperaturen ergibt den maximalen beweglichen Anteil. Dieser ist im allgemeinen kleiner als der über die Dichte bestimmte nichtkristalline Anteil, was auf Existenz von verspannten und daher unbeweglichen Ketten in den nichtkristallinenen Bereichen zurückgeführt wird. Diese Ketten bilden einen starren nichtkristallinen Anteil. Es zeigt sich, daß dieser Anteil bei den von der Kristallisationstemperatur abgeschreckten Proben größer ist als bei den langsam abgekühlten. Bei Auftragung als Funktion der Kristallisationstemperatur besitzt er bei beiden Arten von Proben ein Maximum bei etwa 200°C.
Ionensolvatation
Authors: Strehlow H. , Knoche W. , Schneider H.
Published: August 2023

Es wird über Beiträge zur Kenntnis der Ionensolvatation berichtet, die aus der Kinetik der Ionenassoziation sowie aus der Untersuchung von Elektrolyten in gemischten Lösungsmitteln gewonnen wurden. Ein detailliertes Konzept des Ionenpaares läßt sich formulieren. Methoden zur Bestimmung der auswählenden Solvatation von Ionen in Lösungsmittelgemischen sowie Verfahren zur Abschätzung der freien Solvatationsenthalpie einzelner Ionen mit außerthermodynamischen Modellannahmen werden diskutiert. Korrelationen zwischen diesen thermodynamischen Funktionen für Einzelionen und direkt meßbaren Größen, wie vor allem der Solvensüberführungszahl. werden aufgezeigt.
Biobrennstoffzellen als Stromquellen für implantierte elektronische Geräte
Authors: Rao J. R. , Richter G. , Sturm F. V. , Weidlich E.
Published: August 2023

Eine Glucose‐Sauerstoffzelle zur Langzeitenergieversorgung implantierter elektronischer Geräte besteht aus porösen katalytisch aktiven Elektroden für die Umsetzung der körpereigenen Betriebsstoffe Glucose und Sauerstoff aus der Gewebeflüssigkeit. Wegen der fehlenden Selektivität des Anodenkatalysators für die Glucoseoxidation wird die Glucoseelektrode aus aktivem Edelmetall zwischen zwei dünnen porösen Sauerstoffelektroden aus Kohle angeordnet. Dadurch wird dem herandiffundierenden Gemisch der Reaktionspartner zunächst der Sauerstoff entzogen, während die Glucose durch Diffusion weiter zur Anode gelangen kann.

Eine 1 mm dicke Zelle mit Elektroden von 4 cm Durchmesser liefert in vitro in einer der Körperflüssigkeit ähnlichen Lösung bei einem Lastwiderstand von 2,7 kω 100 μW.
Einfluß der Reaktionsbedingungen bei der Elektrosynthese von zinnorganischen Verbindungen
Authors: Britz D. , Luft H.
Published: August 2023

Die Reduktion von Alkylhalogeniden an einer Zinnkathode in Wasser/Acetonitril‐Gemischen ergibt als Hauptprodukt das jeweilige Trialkylzinnsalz neben geringen Mengen von Tetraalkylzinn und Hexaalkyldizinn. Adsorptionseffekte, wie sie an Blei bei Verwendung von Tensiden zu guten Ausbeuten führen, sind in diesem System von geringer Bedeutung. Das Verhältnis Wasser: Acetonitril hat einen starken Einfluß auf die Reaktionseffizienz, was auf Löslichkeitseffekte und daraus sich ergebende Reduktionspotentialverschiebungen zurückzuführen ist.
Zum Einfluß der Leitfähigkeit von Phthalocyaninen bei der Elektrokatalyse in Brennstoffzellen
Authors: Meier H. , Albrecht W. , Tschirwitz U. , Zimmerhackl E.
Published: August 2023

Zwischen der elektrokatalytischen Aktivität der in Brennstoffzellen eingebauten Phthalocyaninkatalysatoren und deren Leitfähigkeit bestehen verschiedene Zusammenhänge: Unter anderem wird die Elektrokatalyse der Sauerstoffreduktion durch die am besten leitenden Polymere der Fe‐ oder Co‐Phthalocyaningruppe am stärksten aktiviert. Auch wird ein Einfluß der Leitfähigkeit und der mit dieser verbundenen Katalaseaktivität auf die Stabilität länger belasteter Sauerstoffkathoden festgestellt. Die an Fe‐Polyphthalocyaninen beobachtete Störung der pi‐Elektronendelokalisation (Rubikonjugation) und der Nachweis einer Beziehung zwischen Leitfähigkeit einerseits und Elektrokatalyse sowie Katalaseaktivität andererseits führt zu einer die Elektrokatalyse der Sauerstoffreduktion beschreibenden Modellvorstellung. Nach diesem Modell, das u. a. die überragende elektrokatalytische Eignung der Fe‐Polyphthalocyanine erklären kann, spielen bei der Elektrokatalyse sowohl Donatorzustände für die Reduktion des Sauerstoffs als auch Akzeptorzustände für die Zersetzung des H2O2 eine entscheidende Rolle.