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Background The incidence of orthopedic disorders amongst patients with Prader–Willi Syndrome (PWS) is high when compared to the general pediatric population. The purpose of this retrospective study was to define the most commonly performed orthopedic procedures in pediatric patients with PWS and to characterize the peri-operative outcomes of these patients. Methods The Kids Inpatient Database (KID) was queried to collect data and identify all pediatric patients with PWS who underwent orthopedic procedures from 2001 to 2012. A total of 3684 patients with PWS were identified, 334 of who underwent an orthopedic procedure. Population demographics, comorbidities, and specific procedures undergone were defined. The incidences of postoperative complications and length of associated hospital stay were additionally evaluated. Results Mean age of patients in this sample was 10.33 years (SD 4.5). The most common comorbidities included obesity (18.1%), chronic pulmonary disease (14.1%), hypothyroidism (5.1%), hypertension (5.1%), and uncomplicated diabetes (4%). Common procedures were spinal fusion (165/334, 49%) and lower extremity procedures (50/334, 15%). Complications included acute blood loss anemia, device related complications, pneumonia, sepsis, and urinary tract infections. The overall complication rate was 35.6%. Average hospital lengths of stay for patients undergoing spinal fusion was 6.68 days (SD 4.13), lower extremity orthopedic procedure was 5.65 days (SD 7.4), and all other orthopedic procedures was 7.74 days (SD 16.3). Conclusions Orthopedic disorders are common in patients with PWS. Consequently, spinal fusions and lower extremity procedures are commonly performed in this patient population. Associated comorbid conditions may negatively impact surgical outcomes in these patients. This information should prove useful in the peri-operative management of patients with PWS undergoing orthopedic surgery and for shared decision making with families.

Photosynthetic reaction centres catalyse the majority of solar energy conversion on Earth. These pigment proteins achieve this goal with a near-unity quantum efficiency, transducing the energy of almost every absorbed photon into that of a charge separated state. Capturing the high efficiency of these natural proteins with man-made electrodes is the goal of biohybrid technologies such as biophotovoltaics, biofuel cells and biosensors. However, the removal of reaction centres from their natural cellular environment and their integration into an abiotic biohybrid architecture invariably introduces loss channels that compromise energy conversion efficiency. Here, we developed the combined use of spectroscopy and analytical electrochemistry to identify electron transfer bottlenecks, back-reactions and short-circuits that affect the performance of a bacterial reaction centre-based biophotoelectrode. We determined that the system was over 90% efficient under low intensity light but dropped to ~10% efficiency under intense continuous illumination. Limitations and loss processes included bottlenecks in electron transfer that rendered 62% of reaction centres inactive, as well as a short-circuiting of 73% of the photochemical product from active reaction centres. These findings will help shape rational design strategies for improving the performance of biohybrid devices and may be more broadly applied to other donor-acceptor type photocatalysts.

Interest in acquiring green energy from sunlight is driving research into the incorporation of biological photosynthetic materials into biohybrid devices. A potential way to enhance solar energy conversion by photosynthetic proteins is to couple them to plasmonic nanomaterials to enhance absorption of incident radiation. In this work, a variety of plasmonic nanoparticles were used to boost the photocurrent output of a Protein Electricity Generator (PEG). Mixing gold nanoparticles (NPs) of five different architectures into the photoprotein/electrolyte contents of the cell was found to increase device performance, the most effective being ∼120 nm diameter star-shaped clusters that caused a ∼six-fold increase in photocurrent at the optimum dopant level. In addition, high-resolution electrohydrodynamic printing was used to create parallel line and square lattice patterns of silver nanoparticle ink on the tungsten rear electrode of the cells. Patterns with a 700 nm spacing between lines boosted photocurrents by up to three-fold and the effects of the gold and silver nanoparticles were additive, such that the ideal combination produced a ∼19-fold increase in photocurrent and device efficiency. We attribute the elevated performance to plasmonic enhancement of absorbance and scattering effects that increase the path length for photons in the device. Use of rear electrodes with silver nanoparticle lines and grids at 1100 nm spacing did not increase photocurrents, highlighting the importance of precision printing of nanostructures for the enhancement of device performance.

Background and Purpose: Studies of carotid artery disease have suggested that high-grade stenosis can affect cognition, even without stroke. The presence and degree of cognitive impairment in such patients have not been reported and compared with a demographically matched population-based cohort. Methods: We studied cognition in 1000 consecutive CREST-2 (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial) patients, a treatment trial for asymptomatic carotid disease. Cognitive assessment was after randomization but before assigned treatment. The cognitive battery was developed in the general population REGARDS Study (Reasons for Geographic and Racial Differences in Stroke), involving Word List Learning Sum, Word List Recall, and Word List fluency for animal names and the letter F. The carotid stenosis patients were >45 years old with ≥70% asymptomatic carotid stenosis and no history of prevalent stroke. The distribution of cognitive performance for the patients was standardized, accounting for age, race, and education using performance from REGARDS, and after further adjustment for hypertension, diabetes, dyslipidemia, and smoking. Using the Wald Test, we tabulated the proportion of Z scores less than the anticipated deviate for the population-based cohort for representative percentiles. Results: There were 786 baseline assessments. Mean age was 70 years, 58% men, and 52% right-sided stenosis. The overall Z score for patients was significantly below expected for higher percentiles ( P P =0.015). Lower performance was attributed largely to Word List Recall ( P P ≤0.01). The scores for left versus right carotid disease were similar. Conclusions: Baseline cognition of patients with severe carotid stenosis showed below normal cognition compared to the population-based cohort, controlling for demographic and cardiovascular risk factors. This cohort represents the largest group to date to demonstrate that poorer cognition, especially memory, in this disease. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02089217.

The global energy crisis challenges us to develop more efficient strategies for the sustainable production of energy. Given the excellent efficiency of the natural photosynthetic apparatus, biohybrid photovoltaic devices present an attractive solution for solar energy conversion. However, their composition, stability, and complexity can limit their inclusion into photovoltaic devices. Here, we combined computational design and directed evolution to overcome these limitations and create tailor-made photoenzymes. Photo-biocatalysts were designed by introducing photosensitizer binding sites into heme-containing helical bundle proteins. The designed binding sites were specific for the target photosensitizer and readily transplanted into other helical bundles. The best design was highly evolvable and reached nanomolar ligand affinity after mutagenesis and screening. The evolved enzyme generated 2.6 times higher photocurrents than the photosensitizer alone, primarily driven by increased photostability. Evolvability is a unique advantage of our protein-based approach over abiological photovoltaic and will be critical to developing efficient biohybrid systems.Abstract Figure

Spontaneous spinal cerebrospinal fluid (CSF) leak is a condition that commonly presents with debilitating positional headaches. Often, the cause of the leak is located in the spine. Although often cured with conservative management, including epidural blood patching, a subset of patients are refractory to this initial management. Determining the focal location of the spinal leak can, in some patients, require several imaging modalities. Treatment similarly involves multiple options, including targeted epidural blood and/or fibrin patching as well as surgical closure. In this article, we review the current literature regarding this challenging condition and present an algorithm for management.

Background and Purpose: Despite a higher incidence of stroke and a more adverse cardiovascular risk factor profile in Blacks and Hispanics compared with Whites, carotid artery revascularization is performed less frequently among these subpopulations. We assessed racial differences in high-grade (≥70% diameter-reducing) carotid stenosis. Methods: Consecutive clients in a Nationwide Life Line for-Profit Service to screen for vascular disease, 2005 to 2019 were evaluated in a cross-sectional study. The prevalence of high-grade stenosis, defined by a carotid ultrasound peak systolic velocity of ≥230 cm/s, was assessed. Participants self-identified as White, Black, Hispanic, Asian, Native American, or other. Race/ethnic differences were assessed using Poisson regression. The number of individuals in the United States with high-grade stenosis was estimated by applying prevalence estimates to 2015 US Census population estimates. Results: The prevalence of high-grade carotid stenosis was estimated in 6 130 481 individuals. The prevalence of high-grade stenosis was higher with increasing age in all race-sex strata. Generally, Blacks and Hispanics had a lower prevalence of high-grade stenosis compared with Whites, while Native Americans had a higher prevalence. For example, for men aged 55 to 65, the relative risk of stenosis compared with Whites was 0.40 (95% CI, 0.29–0.55) and 0.61 (95% CI, 0.46–0.81) for Blacks and Hispanics, respectively; and 1.53 (95% CI, 1.12–2.10) for Native Americans. When these prevalence estimates were applied to the Census estimates of the US population, an estimated 327 721 individuals have high-grade stenosis, of whom 7% are Black, 7% Hispanic, and 43% women. Conclusions: Despite their having a more adverse cardiovascular risk profile, there was a lower prevalence of high-grade carotid artery stenosis for both the Black and Hispanic relative to the White clients. This lower prevalence of high-grade stenosis is a potential contributor to the lower use of carotid revascularization procedures in these minority populations.

In this study, we report binding free energy calculations of various drugs-of-abuse to Cucurbit-[8]-uril as part of the SAMPL8 blind challenge. Force-field parameters were obtained from force-matching with different quantum mechanical levels of theory. The Replica Exchange Umbrella Sampling (REUS) approach was used with a cylindrical restraint to enhance the sampling of host–guest binding. Binding free energy was calculated by pulling the guest molecule from one side of the symmetric and cylindrical host, then into and through the host, and out the other side (bidirectional) as compared to pulling only to the bound pose inside the cylindrical host (unidirectional). The initial results with force-matched MP2 parameter set led to RMSE of 4.68 $${\text{kcal}}/{\text{mol}}$$ kcal / mol from experimental values. However, the follow-up study with CHARMM generalized force field parameters and force-matched PM6-D3H4 parameters resulted in RMSEs from experiment of $$2.65$$ 2.65 and $$1.72 {\text{kcal}}/{\text{mol}}$$ 1.72 kcal / mol , respectively, which demonstrates the potential of REUS for accurate binding free energy calculation given a more suitable description of energetics. Moreover, we compared the free energies for the so called bidirectional and unidirectional free energy approach and found that the binding free energies were highly similar. However, one issue in the bidirectional approach is the asymmetry of profile on the two sides of the host. This is mainly due to the insufficient sampling for these larger systems and can be avoided by longer sampling simulations. Overall REUS shows great promise for binding free energy calculations.

Die Nutzung natürlicher photosynthetischer Enzyme in biohybriden Anwendungen stellt eine attraktive und potenziell nachhaltige Möglichkeit zur Umwandlung von solarer Energie in Elektrizität und Brennstoffe dar. Jedoch begrenzt die Stabilität von photosynthetisch aktiven Proteinen nach der Implementierung in biohybride Anwendungsdesigns die operative Lebensdauer von Biophotoelektroden auf bisher wenige Stunden. In dieser Publikation demonstrieren wir, wie sich die Stabilität einer mesoporösen Elektrode, welche mit dem Photoprotein RC-LH1 aus Rhodobacter sphaeroides beschichtet ist, erheblich steigern lässt. Durch die Aufrechterhaltung der Elektronenübertragungswege konnte die operative Lebensdauer unter Dauerlicht auf 33 Tage gesteigert werden und die operative Funktionalität nach einer Lagerung über mehr zwei Jahre hinweg demonstriert werden. Kombiniert mit hohen Photoströmen, die Spitzenwerte von 4.6 mA cm−2 erreichten, erzeugte die optimierte Biophotoelektrode eine kumulative Leistung von 86 C cm−2, die höchste bisher berichtete Leistung für diese Art von Elektroden. Unsere Ergebnisse zeigen, dass der Faktor, welcher die Stabilität einschränkt, die Architektur der Struktur ist, die das Photoprotein umgibt, sowie das entsprechende biohybride Sensoren und photovoltaische Geräte mit einer Betriebsdauer von mehreren Jahren möglich sind.

A sample of editorial cartoons published following the wave of accounting scandals in the United States culminating in the collapse of Enron and the demise of the auditors Arthur Andersen LLP was examined to explore the portrayal of accounting, accountants and auditors. The nature and importance of the cartoons was also investigated. While the examination revealed what cartoonists had to say about accounting, accountants and auditing, the purpose was to ascertain the stereotypes conveyed. The cartoonists working from established preconceptions of accounting and accountants redefined and reshaped accounting stereotypes. They replaced the dull but honest image with a negative one, the fraudulent accountant. However, the image of the male accountant survived. As social critics, the cartoonists focused on the consequences on employees and stockholders but neglected to address the consequences for business institutions.

A Roman inscribed grave stela with a rare depiction of a sprit-rigged vessel was discovered in 1998 in the west necropolis of Saraylar on Marmara Island (ancient Proconnesos, modern Balikesir Provi...

Background Deep brain stimulation (DBS) electrode placement utilizing a frame-based technique requires registration of the stereotactic frame with computed tomography (CT) or magnetic resonance (MR) imaging. This traditionally has been accomplished with a conventional CT scanner. In recent years, intraoperative CT has become more prevalent. Objective To compare the coordinates obtained with intraoperative CT and conventional CT for registration of the stereotactic frame for DBS. Methods Patients undergoing DBS electrode placement between 2015 and 2017, who underwent both conventional and intraoperative CT for registration of the stereotactic frame, were included for analysis. The coordinates for the stereotactic target, anterior commissure, and posterior commissure for each CT method were recorded. The mean, maximum, minimum, and standard deviation of the absolute difference for each of the paired coordinates was calculated. Paired t-tests were performed to test for statistical significance of the difference. The directional difference as well as the vector error between the paired coordinates was also calculated. Results The mean absolute difference between conventional and intraoperative CT for the coordinate pairs was less than 0.279 mm or 0.211 degrees for all coordinate pairs analyzed. This was not statistically significant for any of the coordinate pairs. Moreover, the maximum absolute difference between all coordinate pairs was 1.04 mm. Conclusion Intraoperative CT imaging provides stereotactic frame registration coordinates that are similar to those obtained by a standard CT scanner. This may save time and hospital resources by obviating the need for the patient to go to the radiology department for a CT scan.

Biohybrid photoelectrochemical systems in photovoltaic or biosensor applications have gained considerable attention in recent years. While the photoactive proteins engaged in such systems usually maintain an internal charge separation quantum yield of nearly 100%, the subsequent steps of electron and hole transfer beyond the protein often limit the overall system efficiency and their kinetics remain largely uncharacterized. To reveal the dynamics of one of such charge-transfer reactions, we report on the reduction of Rhodobacter sphaeroides reaction centers (RCs) by Os-complex-modified redox polymers (P-Os) characterized using transient absorption spectroscopy. RCs and P-Os were mixed in buffered solution in different molar ratios in the presence of a water-soluble quinone as an electron acceptor. Electron transfer from P-Os to the photoexcited RCs could be described by a three-exponential function, the fastest lifetime of which was on the order of a few microseconds, which is a few orders of magnitude faster than the internal charge recombination of RCs with fully separated charge. This was similar to the lifetime for the reduction of RCs by their natural electron donor, cytochrome c2. The rate of electron donation increased with increasing ratio of polymer to protein concentrations. It is proposed that P-Os and RCs engage in electrostatic interactions to form complexes, the sizes of which depend on the polymer-to-protein ratio. Our findings throw light on the processes within hydrogel-based biophotovoltaic devices and will inform the future design of materials optimally suited for this application.

To uncover the mechanism behind the high photo-electronic conversion efficiency in natural photosynthetic complexes it is essential to trace the dynamics of electronic and vibrational quantum coherences. Here we apply wavelet analysis to two-dimensional electronic spectroscopy data for three purple bacterial reaction centers with mutations that produce drastically different rates of primary charge separation. From the frequency distribution and dynamic evolution features of the quantum beating, electronic coherence with a dephasing lifetime of ~50 fs, vibronic coherence with a lifetime of ~150 fs and vibrational/vibronic coherences with a lifetime of 450 fs are distinguished. We find that they are responsible for, or couple to, different specific steps during the primary charge separation process, i.e., intradimer charge transfer inside the special bacteriochlorophyll pair followed by its relaxation and stabilization of the charge-transfer state. The results enlighten our understanding of how quantum coherences participate in, and contribute to, a biological electron transfer reaction.

Accurately computing partition coefficients is a pivotal part of drug discovery. Specifically, octanol-water partition coefficients can provide information into hydrophobicity of drug-like molecules, as well as a de facto representation of membrane permeability. However, one challenge facing the computation of partition coefficients is the need to encapsulate various microscopic environments. These include areas of largely bulk solvent (i.e., either water or octanol) or regions where octanol is saturated with water or areas of higher salt concentration. Also, tautomeric effects require consideration. Thus, we present a Boltzmann weighting approach that incorporates transfer free energies across varying microscopic media, as well as varying tautomeric state, to compute partition coefficients in the SAMPL6 challenge.

Two different types of approaches: (a) approaches that combine quantitative structure activity relationships, quantum mechanical electronic structure methods, and machine-learning and, (b) electronic structure vertical solvation approaches, were used to predict the logP coefficients of 11 molecules as part of the SAMPL6 logP blind prediction challenge. Using electronic structures optimized with density functional theory (DFT), several molecular descriptors were calculated for each molecule, including van der Waals areas and volumes, HOMO/LUMO energies, dipole moments, polarizabilities, and electrophilic and nucleophilic superdelocalizabilities. A multilinear regression model and a partial least squares model were used to train a set of 97 molecules. As well, descriptors were generated using the molecular operating environment and used to create additional machine learning models. Electronic structure vertical solvation approaches considered include DFT and the domain-based local pair natural orbital methods combined with the solvated variant of the correlation consistent composite approach.

Human-machine interfaces in emerging smart-skin technologies tend to be focussed towards high-sensitivity tactile sensing primarily with visual/numerical feedback, and research on e-skin technologies for the visually impaired is sparse. Here we demonstrate a proof-of-concept six-pixel tactile sensor that converts touch stimuli based on Braille codes into an auditory output, and which could potentially be miniaturized as an ‘energy-autonomous on-skin e-Braille reader’ for the visually impaired. By applying the concepts of electric double layer capacitance and bio-photo capacitance, a self-powered sensor is constructed that generates electrical signals as large as 2 V by modulating a bio-electrochemical liquid bridge between electrodes of opposite wetting characteristics. The liquid bridge, composed of photosynthetic pigment-proteins with a redox electrolyte, both augments the sensory response and serves as a standalone solar-capacitor that can generate a photocurrent as high as 140 µA cm-2, and which displays a long discharge time of ~20 mins with just ~3 mins of photo charging.

The exploitation of natural photosynthetic enzymes in semi-artificial devices constitutes an attractive and potentially sustainable route for the conversion of solar energy into electricity and solar fuels. However, the stability of photosynthetic proteins after incorporation in a biohybrid architecture typically limits the operational lifetime of biophotoelectrodes to a few hours. Here, we demonstrate ways to greatly enhance the stability of a mesoporous electrode coated with the RC-LH1 photoprotein from Rhodobacter sphaeroides. By preserving electron transfer pathways, we extended operation under continuous high-light to 33 days, and operation after storage to over two years. Coupled with large photocurrents that reached peak values of 4.6 mA cm−2, the optimized biophotoelectrode produced a cumulative output of 86 C cm−2, the largest reported performance to date. Our results demonstrate that the factor limiting stability is the architecture surrounding the photoprotein, and that biohybrid sensors and photovoltaic devices with operational lifetimes of years are feasible.

Background and importance Chronic neuropathic facial pain is a debilitating disease that can be approached with multiple different treatment modalities. Cervical spinal cord stimulation has been demonstrated to be effective for patients suffering from neuropathic facial pain. Consensus does not exist in the literature regarding technique for placement. Clinical presentation A 49-yr-old female presented with chronic intractable neuropathic facial pain. She underwent a successful percutaneous spinal cord stimulation trial, followed by placement of a paddle electrode for permanent implantation. The paddle electrode failed to duplicate the pain relief of her trial. Measurement of the width of the paddle demonstrated that it was 2 mm smaller than the separation of the percutaneous trial electrodes. Electrodes with wider interelectrode distance were then placed with satisfactory pain relief. Conclusion Although conventional spinal cord stimulation targets the dorsal columns, cervical spinal cord stimulation for facial pain targets the spinal trigeminal nucleus. The effectiveness of stimulation may be increased with a more laterally positioned electrode in order to recruit the more laterally positioned spinal trigeminal nucleus. This case report illustrates the importance of this anatomic consideration.

Accurately predicting free energy differences is essential in realizing the full potential of rational drug design. Unfortunately, high levels of accuracy often require computationally expensive QM/MM Hamiltonians. Fortuitously, the cost of employing QM/MM approaches in rigorous free energy simulation can be reduced through the use of the so-called “indirect” approach to QM/MM free energies, in which the need for QM/MM simulations is avoided via a QM/MM “correction” at the classical endpoints of interest. Herein, we focus on the computation of QM/MM binding free energies in the context of the SAMPL8 Drugs of Abuse host–guest challenge. Of the 5 QM/MM correction coupled with force-matching submissions, PM6-D3H4/MM ranked submission proved the best overall QM/MM entry, with an RMSE from experimental results of 2.43 kcal/mol (best in ranked submissions), a Pearson’s correlation of 0.78 (second-best in ranked submissions), and a Kendall $$\tau$$ τ correlation of 0.52 (best in ranked submissions).

For decades, Global Navigation Satellite System (GNSS) payloads have incorporated multiple Atomic Frequency Standards (AFS) to provide both redundancy and technology diversity. As space borne AFS have matured, they have demonstrated sufficient reliability to allow multiple AFS to remain active without significantly impacting mission life. Through the use of precise onboard measurements of the relative phases of the active AFS and a voltage controlled crystal oscillator an ensemble of the onboard clocks may be realized. For payloads with three active AFS an improvement in stability, and thus the clock component to User Range Error (URE), of a factor of 1.7 is realized for all averaging times beyond the phase locked loop time constant. In addition, it has been shown that while overall AFS reliability has been excellent, they have experienced occasional anomalous frequency and phase shifts throughout their life requiring control segment intervention. The operation of multiple AFS allows monitoring each of the clocks with respect to the other and autonomously correct for these anomalies. An evaluation of the key parameters governing the performance of these algorithms, along with their impact on URE, will be presented.

We investigated the influence of a range of factors—temperature, redox midpoint potential of an electron carrier, and protein dynamics—on nanosecond electron transfer within a protein. The model reaction was back electron transfer from a bacteriopheophytin anion, HA−, to an oxidized primary electron donor, P+, in a wild type Rhodobacter sphaeroides reaction center (RC) with a permanently reduced secondary electron acceptor (quinone, QA−). Also used were two modified RCs with single amino acid mutations near the monomeric bacteriochlorophyll, BA, located between P and HA. Both mutant RCs showed significant slowing down of this back electron transfer reaction with decreasing temperature, similar to that observed with the wild type RC, but contrasting with a number of single point mutant RCs studied previously. The observed similarities and differences are explained in the framework of a (P+BA− ↔ P+HA−) equilibrium model with an important role played by protein relaxation. The major cause of the observed temperature dependence, both in the wild type RC and in the mutant proteins, is a limitation in access to the thermally activated pathway of charge recombination via the state P+BA− at low temperatures. The data indicate that in all RCs both charge recombination pathways, the thermally activated one and a direct one without involvement of the P+BA− state, are controlled by the protein dynamics. It is concluded that the modifications of the protein environment affect the overall back electron transfer kinetics primarily by changing the redox potential of BA and not by changing the protein relaxation dynamics.

Reaction centers (RCs) are the pivotal component of natural photosystems, converting solar energy into the potential difference between separated electrons and holes that is used to power much of biology. RCs from anoxygenic purple photosynthetic bacteria such as Rhodobacter sphaeroides only weakly absorb much of the visible region of the solar spectrum, which limits their overall light-harvesting capacity. For in vitro applications such as biohybrid photodevices, this deficiency can be addressed by effectively coupling RCs with synthetic light-harvesting materials. Here, we studied the time scale and efficiency of Forster resonance energy transfer (FRET) in a nanoconjugate assembled from a synthetic quantum dot (QD) antenna and a tailored RC engineered to be fluorescent. Time-correlated single-photon counting spectroscopy of biohybrid conjugates enabled the direct determination of FRET from QDs to attached RCs on a time scale of 26.6 ± 0.1 ns and with a high efficiency of 0.75 ± 0.01.

© 2021 American Chemical Society.Despite extensive study, mysteries remain regarding the highly efficient ultrafast charge separation processes in photosynthetic reaction centers (RCs). In this work, transient Stark signals were found to be present in ultrafast two-dimensional electronic spectra recorded for purple bacterial RCs at 77 K. These arose from the electric field that is inherent to the intradimer charge-transfer intermediate of the bacteriochlorophyll pair (P), PA+PB-. By comparing three mutated RCs, a correlation was found between the efficient formation of PAA+PB- and a fast charge separation rate. Importantly, the energy level of P∗ was changed due to the Stark shift, influencing the driving force for P∗ → P+BA- electron transfer and hence its rate. Furthermore, the orientation and amplitude of the inherent electric field varied in different ways upon different mutation, leading to contrasting changes in the rates. This mechanism of modulation provides a solution to a long-lasting inconsistency between experimental observations and activation energy theory.