Guest Molecule-Mediated Energy Harvesting in a Conformationally Sensitive Peptide-Metal Organic Framework.

The apparent piezoelectricity of biological materials is not yet fully understood at the molecular level. In particular, dynamic noncovalent interactions, such as host-guest binding, are not included in the classical piezoelectric model, which limits the rational design of eco-friendly piezoelectric supramolecular materials. Here, inspired by the conformation-dependent mechanoresponse of the Piezo channel proteins, we show that guest-host interactions can amplify the electromechanical response of a conformationally mobile peptide metal-organic framework (MOF) based on the endogenous carnosine dipeptide, demonstrating a new type of adaptive piezoelectric supramolecular material. Density functional theory (DFT) predictions validated by piezoresponse force microscopy (PFM) measurements show that directional alignment of the guest molecules in the host carnosine-zinc peptide MOF channel determines the macroscopic electromechanical properties. We produce stable, robust 1.4 V open-circuit voltage under applied force of 25 N with a frequency of 0.1 Hz. Our findings demonstrate that the regulation of host-guest interactions could serve as an efficient method for engineering sustainable peptide-based power generators.

A Piezoelectric Ionic Cocrystal of Glycine and Sulfamic Acid.

Cocrystallization of two or more molecular compounds can dramatically change the physicochemical properties of a functional molecule without the need for chemical modification. For example, coformers can enhance the mechanical stability, processability, and solubility of pharmaceutical compounds to enable better medicines. Here, we demonstrate that amino acid cocrystals can enhance functional electromechanical properties in simple, sustainable materials as exemplified by glycine and sulfamic acid. These coformers crystallize independently in centrosymmetric space groups when they are grown as single-component crystals but form a noncentrosymmetric, electromechanically active ionic cocrystal when they are crystallized together. The piezoelectricity of the cocrystal is characterized using techniques tailored to overcome the challenges associated with measuring the electromechanical properties of soft (organic) crystals. The piezoelectric tensor of the cocrystal is mapped using density functional theory (DFT) computer models, and the predicted single-crystal longitudinal response of 2 pC/N is verified using second-harmonic generation (SHG) and piezoresponse force microscopy (PFM). The experimental measurements are facilitated by polycrystalline film growth that allows for macroscopic and nanoscale quantification of the longitudinal out-of-plane response, which is in the range exploited in piezoelectric technologies made from quartz, aluminum nitride, and zinc oxide. The large-area polycrystalline film retains a damped response of ≥0.2 pC/N, indicating the potential for application of such inexpensive and eco-friendly amino acid-based cocrystal coatings in, for example, autonomous ambient-powered devices in edge computing.

Mentoring in Global Cancer Research Training.

This manuscript illustrates general concepts of mentoring in low- and middle-income countries (LMICs). The focus of this manuscript is on public health research based on our experiences with the Cancer Epidemiology Education in Special Populations (CEESP) Program which is further illustrated in this Supplement. While the CEESP Program provides research training in global and US minority settings, this manuscript is focused on the global aspects of the program. We describe the process of selecting students into the CEESP Program, the process of mentoring them, and the preparation of the mentoring sites. We emphasize the review of the CEESP mentors in LMICs and put forward recommendations for enhancing their mentoring skills and disseminating the experience to other US and global institutions interested in global cancer education.

Molecular engineering of piezoelectricity in collagen-mimicking peptide assemblies.

Realization of a self-assembled, nontoxic and eco-friendly piezoelectric device with high-performance, sensitivity and reliability is highly desirable to complement conventional inorganic and polymer based materials. Hierarchically organized natural materials such as collagen have long been posited to exhibit electromechanical properties that could potentially be amplified via molecular engineering to produce technologically relevant piezoelectricity. Here, by using a simple, minimalistic, building block of collagen, we fabricate a peptide-based piezoelectric generator utilising a radically different helical arrangement of Phe-Phe-derived peptide, Pro-Phe-Phe and Hyp-Phe-Phe, based only on proteinogenic amino acids. The simple addition of a hydroxyl group increases the expected piezoelectric response by an order of magnitude (d35 = 27 pm V-1). The value is highest predicted to date in short natural peptides. We demonstrate tripeptide-based power generator that produces stable max current >50 nA and potential >1.2 V. Our results provide a promising device demonstration of computationally-guided molecular engineering of piezoelectricity in peptide nanotechnology.

Diphenylalanine-Derivative Peptide Assemblies with Increased Aromaticity Exhibit Metal-like Rigidity and High Piezoelectricity.

Diphenylalanine (FF) represents the simplest peptide building block that self-assembles into ordered nanostructures with interesting physical properties. Among self-assembled peptide structures, FF nanotubes display notable stiffness and piezoelectric parameters (Young's modulus = 19-27 GPa, strain coefficient d33 = 18 pC/N). Yet, inorganic alternatives remain the major materials of choice for many applications due to higher stiffness and piezoelectricity. Here, aiming to broaden the applications of the FF motif in materials chemistry, we designed three phenyl-rich dipeptides based on the ß,ß-diphenyl-Ala-OH (Dip) unit: Dip-Dip, cyclo-Dip-Dip, and tert-butyloxycarbonyl (Boc)-Dip-Dip. The doubled number of aromatic groups per unit, compared to FF, produced a dense aromatic zipper network with a dramatically improved Young's modulus of ∼70 GPa, which is comparable to aluminum. The piezoelectric strain coefficient d33 of ∼73 pC/N of such assembly exceeds that of poled polyvinylidene-fluoride (PVDF) polymers and compares well to that of lead zirconium titanate (PZT) thin films and ribbons. The rationally designed π-π assemblies show a voltage coefficient of 2-3 Vm/N, an order of magnitude higher than PVDF, improved thermal stability up to 360 °C (∼60 °C higher than FF), and useful photoluminescence with wide-range excitation-dependent emission in the visible region. Our data demonstrate that aromatic groups improve the rigidity and piezoelectricity of organic self-assembled materials for numerous applications.

Piezoelectricity in the Intervertebral disc.

Lower back pain is a major global health challenge that can often be caused by degeneration of the Intervertebral Disc (IVD). While IVD biomechanics are a key factor in the degenerative cycle, many mechanotransduction pathways remain unknown, in particular the electro-mechanical coupling in the loaded tissue. However, despite evidence for a role in the mechanically-induced remodelling of similar tissue, piezoelectricity has been overlooked in the IVD. In this study, we investigate the piezoelectric properties of the Annulus Fibrosus (AF) and the Nucleus Pulposus (NP) by measuring the direct piezoelectric effect of mechanically-induced electrical potential change. To verify these findings, we conducted Piezoresponse Force Microscopy (PFM) to measure the inverse effect of electrically-induced deformation. We demonstrate that, for the first time, piezoelectricity is generated throughout the IVD. Piezoelectric effects were greater in the AF than the NP, owing to the organised collagen networks present. However, the piezoresponse found in the NP indicates piezoelectric properties of non-collagenous proteins that have not yet been studied. The voltage generated by longitudinal piezoelectricity in-vivo has been calculated to be ~1 nV locally, indicating that piezoelectric effects may directly affect cell alignment in the AF and may work in conjunction with streaming potentials throughout the IVD. In summary, we have highlighted an intricate electro-mechanical coupling that appears to have distinct physiological roles in the AF and NP. Further study is required to elucidate the cell response and determine the potential role of piezoelectric effects in regeneration and preventative measures from degeneration.

How Can Physicians in Training Tap into the Wisdom of Senior Physicians?

This piece reflects on an innovative project that we undertook: interviewing master physicians across the world of oncology and asking them what was their secret to success. It provides insights into the answers received from over fifty interviews and the process that was followed.

Racemic Amino Acid Piezoelectric Transducer.

Single crystal L-amino acids can exhibit technologically useful piezoelectric and nonlinear optical properties. Here we predict, using density functional theory, the piezoelectric charge and strain and voltage tensors of the racemic amino acid DL alanine, and use the modeling data to guide the first macroscopic and nanoscopic piezoelectric measurements on DL-alanine single crystals and polycrystalline aggregates. We demonstrate voltage generation of up to 0.8 V from DL-alanine crystal films under simple manual compression, twice as high as other amino acid crystals. Our results suggest that net molecular chirality is not a prerequisite for piezoelectric behavior in organic crystals. The transducer presented herein demonstrates that DL-alanine crystals can be used in applications such as temperature and force measurement in biosensors, data storage in flexible electronic devices, and mechanical actuation in energy harvesters.

Thirty Years of the Journal of Cancer Education: a Review.

Since its foundation in 1986, the Journal of Cancer Education (JCE) has served as an important outlet for myriad aspects of cancer education and currently serves as the official journal of the American and European Associations for Cancer Education. During its history, the JCE has been under the auspices of five publishers, with its first full year under the current publisher, Springer, in 2010. Print and distribution metrics from 2010 to present were obtained from Springer. These were compared to historical data including the first 10 years of the JCE, published by Dr. Bakemeier in 1995. Since its beginning, the JCE has consisted of four issues per year. The original contract for 256 pages per year has increased to an average of 858 pages from 2010 to 2014. In 2015, the JCE received a total of 344 submissions, up from 339 in 2014, and 262 the year before. This is a stark contrast to the roughly 44 submission received in 1994. Over this same period, the overall rejection rate has increased from 30% in 2010 to 45% in 2015. The number of online deals has increased from 347 in 2014 to 361 in 2015 and has been accompanied by a steady increase in the number of full-text article downloads: 19,000 in 2010 to 58,923 in 2015. Accordingly, the JCE has seen a pronounced and steady increase in impact factor, rising from 0.52 in 2009 to 1.368 in 2015. Since moving to Springer, the JCE has seen unprecedented growth, receiving increasing submissions yearly, an increasing number of subscription deals and online full-text downloads, and a corresponding increase in impact factor.

An Overview of the History of Orthopedic Surgery.

Orthopedic surgery has a long and rich history. While the modern term orthopedics was coined in the 1700s, orthopedic principles were beginning to be developed and used during primitive times. The Egyptians continued these practices, and described ways to recognize and manage common orthopedic conditions. The Greeks and Romans subsequently began to study medicine in a systematic manner, and greatly improved our understanding of orthopedic anatomy and surgical technique. After a period of little progress during the Middle Ages, rapid advancement was noted during the Renaissance, including the description of various injuries, improvements in surgical technique, and development of orthopedic hospitals. Collectively, these advances provided the foundation for modern orthopedics. Currently, orthopedic surgery is a rapidly developing field that has benefited from the works of numerous scholars and surgeons. It is important to recognize the successes and failures of the past, in order to advance research and practice as well as improve patient care and clinical outcomes.

Gold Humanism Honor Society Election and Academic Outcomes: A 10-Institution Study.

BACKGROUND AND OBJECTIVES: This study examines relationships among election to the Gold Humanism Honor Society (GHHS) and election to Alpha Omega Alpha (AOA), class rank, and residency selection to determine if GHHS members are more likely to select primary care residencies than students not elected to GHHS membership. METHODS: We evaluated five graduating classes (2006--2010) at 10 medical schools (n=5,481 students). Residency selections were grouped into primary care (family medicine, internal medicine, pediatrics, OB-GYN), surgery (including surgical specialties), or E-ROAD and other (including lifestyle practices-emergency medicine, radiology, ophthalmology, anesthesiology, and dermatology plus all other specialties, eg, neurology, pathology). RESULTS: A higher proportion of GHHS members were attracted to primary care compared to non-GHHS members (54.3% versus 44.5%). Additional comparisons between GHHS and non-GHHS members demonstrated that 33.1% of GHHS members matched into E-ROAD and other residencies, while 40.9% of non-GHHS went into one of these specialties. Fewer GHHS members chose general surgery or a surgical sub-specialty (12.6% versus 14.6%). More GHHS members were elected into AOA (30.3% versus 14.0%). Further, a far greater proportion of dual AOA/GHHS members elect family medicine residency versus AOA members not elected to GHHS. In addition, GHHS members had slightly higher mean scores on USMLE Step 1 and 2 CK (Clinical Knowledge) and mean class rank. CONCLUSIONS: This study demonstrates that students elected into the GHHS as an aggregate group tend to be academically higher achieving when compared to their non-GHHS peers and gravitate to a higher degree toward primary care and specifically to family medicine.