The role of 2D material families in energy harvesting: An editorial overview

The ever increasing proportion of an energy consuming society and the boost in industrialization accelerated the depletion of fossil fuel based energy sources at an alarming rate. This emphasizes the necessity of sustainable energy generation and storage to meet the daily energy demands. But, these alternative renewable energy sources like solar and wind power are intermittent and highly depend on weather, place and individuals. This creates the inevitability of suitable energy storage devices like batteries and supercapacitors. The interfacing of energy storing devices is required to maintain the supply chain equilibrium, power efficiency, regulate power fluctuations and reduce pollution. Besides, the boom in electric mobility and consumer electronics also require uninterrupted power supply. Hence, in the upcoming years the energy storing devices play a vital role in addressing the energy crisis. Innovations in new materials and technologies will be the core area of research and development in the coming future. 2D materials like graphene,transition metal carbides and nitrides (MXenes), transition metal borides (MBenes) and so on are the new class of materials among them MXenes are getting more attention in energy storage owing to its exceptional properties.

PET/MR Imaging in Evaluating Treatment Failure of Head and Neck Malignancies: A Neck Imaging Reporting and Data System-Based Study

BACKGROUND AND PURPOSE

PET/MR imaging is a relatively new hybrid technology that holds great promise for the evaluation of head and neck cancer. The aim of this study was to assess the performance of simultaneous PET/MR imaging versus MR imaging in the evaluation of posttreatment head and neck malignancies, as determined by its ability to predict locoregional recurrence or progression after imaging.

MATERIALS AND METHODS

The electronic medical records of patients who had posttreatment PET/MR imaging studies were reviewed, and after applying the exclusion criteria, we retrospectively included 46 studies. PET/MR imaging studies were independently reviewed by 2 neuroradiologists, who recorded scores based on the Neck Imaging Reporting and Data System (using CT/PET-CT criteria) for the diagnostic MR imaging sequences alone and the combined PET/MR imaging. Treatment failure was determined with either biopsy pathology or initiation of new treatment. Statistical analyses including univariate association, interobserver agreement, and receiver operating characteristic analysis were performed.

RESULTS

There was substantial interreader agreement among PET/MR imaging scores (κ = 0.634; 95% CI, 0.605-0.663). PET/MR imaging scores showed a strong association with treatment failure by univariate association analysis, with P < .001 for the primary site, neck lymph nodes, and combined sites. Receiver operating characteristic curves of PET/MR imaging scores versus treatment failure indicated statistically significant diagnostic accuracy (area under curve range, 0.864-0.987; P < .001).

CONCLUSIONS

Simultaneous PET/MR imaging has excellent discriminatory performance for treatment outcomes of head and neck malignancy when the Neck Imaging Reporting and Data System is applied. PET/MR imaging could play an important role in surveillance imaging for head and neck cancer.

Experimental and Simulation Studies on Nonwoven Polypropylene-Nitrile Rubber Blend: Recycling of Medical Face Masks to an Engineering Product

The battle against the COVID-19 pandemic counters the waste management system, as billions of single-use face masks are used per day all over the world. Proper disposal of used face masks without jeopardizing the health and the environment is a challenge. Herein, a novel method for recycling of medical face masks has been studied. This method incorporates the nonwoven polypropylene (PP) fiber, which is taken off from the mask after disinfecting it, with acrylonitrile butadiene rubber (NBR) using maleic anhydride as the compatibilizer, which results in a PP-NBR blend with a high percentage economy. The PP-NBR blends show enhanced thermomechanical properties among which, 70 wt % PP content shows superior properties compared to other composites with 40, 50, and 60 wt % of PP. The fully Atomistic simulation of PP-NBR blend with compatibilizer shows an improved tensile and barrier properties, which is in good agreement with the experimental studies. The molecular dynamics simulation confirms that the compatibility between non-polar PP and polar NBR phases are vitally important for increasing the interfacial adhesion and impeding the phase separation.

A comparison of preincisional and postincisional ultrasound guided transversus abdominis plane block

Background and Aims:

Transversus abdominis plane blocks are part of the multimodal analgesia used for lower abdominal surgeries.Our aim of this study was to compare the analgesic efficacy of preincisional and postincisional TAP blocks in patients undergoing total abdominal hysterectomies.

Material and Methods:

54 American Society of Anesthesiologists physical status I and II patients aged between 30 and 60 years who underwent a total abdominal hysterectomy under spinal anesthesia in our hospital were chosen for the study. Alternate patients satisfying the inclusion criteria were either given a preincisional or postincisional transversus abdominis plane block bilaterally. Postoperatively, the numeric pain intensity scale was observed, along with nausea, vomiting, and sedation scores.

Results:

Pain scores were significantly lower (P < 0.05) in the preincisional TAP block group from the 2^nd postoperative hour onwards till 12 h, and thereafter it was comparable between both the groups. The total morphine requirement was significantly less in the preincisional TAP group (P-value 0.001). Also, the mean time to the first request for morphine was significantly longer in patients belonging to the preincisional TAP block group (P-value of 0.002). There were no significant differences in the sedation scores postoperatively, except at the 4^th hour, where it was significantly higher (P-value of 0.024) in the postincisional TAP group. Post operative nausea and vomiting was significantly higher and so the dose of the antiemetic used was also observed to be more in the postincisional TAP block group.

Conclusion:

Preincisional TAP blocks are more effective than postincisional ones with better analgesia and lesser side effects, for total abdominal hysterectomies.

Hyperpolarized relaxometry based nuclear T1 noise spectroscopy in diamond

The origins of spin lifetimes in quantum systems is a matter of importance in several areas of quantum information. Spectrally mapping spin relaxation processes provides insight into their origin and motivates methods to mitigate them. In this paper, we map nuclear relaxation in a prototypical system of [Formula: see text] nuclei in diamond coupled to Nitrogen Vacancy (NV) centers over a wide field range (1 mT-7 T). Nuclear hyperpolarization through optically pumped NV electrons allows signal measurement savings exceeding million-fold over conventional methods. Through a systematic study with varying substitutional electron (P1 center) and [Formula: see text] concentrations, we identify the operational relaxation channels for the nuclei at different fields as well as the dominant role played by [Formula: see text] coupling to the interacting P1 electronic spin bath. These results motivate quantum control techniques for dissipation engineering to boost spin lifetimes in diamond, with applications including engineered quantum memories and hyperpolarized [Formula: see text] imaging.

Tailor-Made Electrospun Multilayer Composite Polymer Electrolytes for High-Performance Lithium Polymer Batteries

A novel tailor-made multilayer composite polymer electrolyte, consisting of two outer layers of electrospun polyacrylonitrile (PAN) and one inner layer of poly(vinyl acetate) (PVAc)/poly(methyl methacrylate) (PMMA)/poly(ethylene oxide) (PEO) fibrous membrane, was prepared using continuous electrospinning. These membranes, which are made up of fibers with diameters in the nanometer range, were stacked in layers to produce interconnected pores that result in a high porosity. Gel polymer electrolytes (GPEs) were prepared by entrapping a liquid electrolyte (1 M LiPF6 in ethylene carbonate/dimethyl carbonate) in the membranes. The composite membranes exhibited a high electrolyte uptake of 450-510%, coupled with an improved room temperature ionic conductivity of up to 4.72 mS cm-1 and a high electrochemical stability of 4.6 V versus Li/Li+. Electrochemical investigations of a composite membrane of PAN-PVAc-PAN, with a LiFePO4 cathode synthesized in-house, showed a high initial discharge capacity of 145 mAh g-1, which corresponds to 85% utilization of the active material, and displayed stable cycle performance.

Correlates of physical function among stroke survivors: an examination of the 2015 BRFSS

OBJECTIVES

To identify the characteristics of stroke survivors with poor physical function.

STUDY DESIGN

Cross-sectional.

METHODS

Secondary data analyses were performed with the 2015 Behavioral Risk Factor Surveillance System data set. Unadjusted and adjusted logistic regressions were employed to determine the correlates of poor physical function in stroke survivors. Self-reported difficulty with walking and stairs was used as a proxy for physical function. Characteristics such as age, race, sex, difficulty doing errands alone, difficult dressing or bathing alone, health care coverage, time since last routine checkup, and reported financial difficulty with regard to health care access were examined as contributing factors to physical function.

RESULTS

Approximately half of all stroke survivors reported having difficulty with walking and stairs (50.3%). As expected, the odds of reporting difficulty with walking and stairs were higher among stroke survivors aged 40 years and above (p < 0.0001). Interestingly, black/African American and multiracial respondents had higher odds of reporting difficulty with walking and stairs than whites, whereas Hispanic respondents had lower odds of reporting difficulty with walking and stairs than whites (p < 0.0001). Further analyses revealed that the disparity of physical function was preserved (p < 0.0001) after adjusting for age, race, sex, education level, family income, marital status, employment status, health insurance status, affordability of healthcare, and length of time from last doctor's visit.

CONCLUSIONS

There were racial/ethnic disparities in physical function. Specifically, blacks/ African Americans had a 5.6% increase in the odds of reporting difficulty with walking and stairs than whites. Moreover, Hispanics reported significantly fewer problems than whites. Overall, similar sociocultural patterns in non-stroke and stroke populations were observed in this study.

Carotid Bulb Webs as a Cause of "Cryptogenic" Ischemic Stroke

BACKGROUND AND PURPOSE

Carotid webs are intraluminal shelf-like filling defects at the carotid bulb with recently recognized implications in patients with recurrent ischemic stroke. We sought to determine whether carotid webs are an under-recognized cause of "cryptogenic" ischemic stroke and to estimate their prevalence in the general population.

MATERIALS AND METHODS

A retrospective review of neck CTA studies in young patients with cryptogenic stroke over the past 6 years (n = 33) was performed to determine the prevalence of carotid webs compared with a control group of patients who received neck CTA studies for reasons other than ischemic stroke (n = 63).

RESULTS

The prevalence of carotid webs in the cryptogenic stroke population was 21.2% (95% CI, 8.9%-38.9%). Patients with symptomatic carotid webs had a mean age of 38.9 years (range, 30-48 years) and were mostly African American (86%) and women (86%). In contrast, only 1.6% (95% CI, 0%-8.5%) of patients in the control group demonstrated a web. Our findings demonstrate a statistically significant association between carotid webs and ischemic stroke (OR = 16.7; 95% CI, 2.78-320.3; P = .01).

CONCLUSIONS

Carotid webs exhibit a strong association with ischemic stroke, and their presence should be suspected in patients lacking other risk factors, particularly African American women.

Prevalence of pressure sores in a community sample of spinal injury patients

Objectives: To estimate the point prevalence of pressure sores in a community sample of spinal cord injured patients who were followed up by a spinal injuries unit and to evaluate whether self-management strategies were associated with decreased risk of pressure sores.

Setting: A regional spinal injuries unit, UK.

Design: Postal questionnaire survey. Main outcome measure: Presence of pressure sores.

Subjects: All patients who were being followed up on a regular basis by the unit.

Results: Out of 760, 520 replied to the questionnaire; 472 were eligible for analysis. Point prevalence of pressure sores was 23% (99). Failure to inspect the skin daily for pressure damage was associated with decreased prevalence of pressure sores (odds ratio (OR) 0.5; 95% confidence interval (CI) 0.2–0.83). Those who inspected their skin daily, however, had a higher proportion of stage I pressure sores, but this was not statistically significant. Smoking (OR 1.8; 95% CI 1–3.3) and pre-existing medical problems (OR 1.8; 95% CI 1–3) were associated with increased prevalence of pressure sores. Regular lifting of weight at least once in an hour while seated, age, gender, neurological level, employment status, living alone and faecal and urinary incontinence were not significant predictors of pressure sores.

Conclusions: Nearly one-quarter of participants had pressure sores at the time of the survey. Periodic weight lifts and daily inspection of skin for pressure damage were not associated with decreased prevalence of pressure sores in this sample. However, those who inspected skin daily tended to detect pressure damage early.

Enhanced supercapacitor performance of a 3D architecture tailored using atomically thin rGO–MoS2 2D sheets

A stable, conductive, additive-free and scalable 3D architecture supercapacitor electrode fabricated by atomically thin 2D sheets of GO and MoS₂ shows superior electrochemical properties which are further substantiated using MD simulations.

Synthesis of Low-Density, Carbon-Doped, Porous Hexagonal Boron Nitride Solids

Here, we report the scalable synthesis and characterization of low-density, porous, three-dimensional (3D) solids consisting of two-dimensional (2D) hexagonal boron nitride (h-BN) sheets. The structures are synthesized using bottom-up, low-temperature (∼300 °C), solid-state reaction of melamine and boric acid giving rise to porous and mechanically stable interconnected h-BN layers. A layered 3D structure forms due to the formation of h-BN, and significant improvements in the mechanical properties were observed over a range of temperatures, compared to graphene oxide or reduced graphene oxide foams. A theoretical model based on Density Functional Theory (DFT) is proposed for the formation of h-BN architectures. The material shows excellent, recyclable absorption capacity for oils and organic solvents.

Postoperative Imaging Findings following Sigmoid Sinus Wall Reconstruction for Pulse Synchronous Tinnitus

BACKGROUND AND PURPOSE

Transmastoid sigmoid sinus wall reconstruction is a surgical technique increasingly used for the treatment of pulsatile tinnitus arising from sigmoid sinus wall anomalies. The imaging appearance of the temporal bone following this procedure has not been well-characterized. The purpose of this study was to evaluate the postoperative imaging appearance in a group of patients who underwent this procedure.

MATERIALS AND METHODS

The medical records of 40 consecutive patients who underwent transmastoid sigmoid sinus wall reconstruction were reviewed. Thirteen of 40 patients underwent postoperative imaging. Nineteen CT and 7 MR imaging examinations were assessed for the characteristics of the materials used for reconstruction, the impact of these on the adjacent sigmoid sinus, and complications.

RESULTS

Tinnitus resolved in 38 of 40 patients. Nine patients were imaged postoperatively for suspected complications, including dural sinus thrombosis, facial swelling, and wound drainage. Two patients underwent imaging for persistent tinnitus, and 2, for development of tinnitus on the side contralateral to the side of surgery. The materials used for reconstruction (NeuroAlloderm, HydroSet, bone pate) demonstrated characteristic imaging appearances and could be consistently identified. In 5 of 13 patients, there was extrinsic compression of the sigmoid sinus by graft material. Dural sinus thrombosis occurred in 2 patients.

CONCLUSIONS

The imaging findings following sigmoid sinus wall repair are characteristic. Graft materials may result in extrinsic compression of the sigmoid sinus, and this finding may be confused with dural venous thrombosis. Awareness of the imaging characteristics of the graft materials used enables this differentiation.

The "boomerang" malleus-incus complex in congenital aural atresia

"Boomerang" malleus-incus fusion deformity is identified on axial high-resolution CT in a subset of patients with congenital aural atresia, and it is associated with an absent incudostapedial joint and stapes capitulum and attachment of the incus to the tympanic segment of the facial nerve canal. Twelve patients with this deformity were identified on a retrospective review of imaging from a cohort of 673 patients with congenital aural atresia, with surgical confirmation in 9 of these patients. Eight of 9 patients underwent partial ossicular replacement prosthesis reconstruction with improvement in hearing outcome. We hypothesize that the boomerang anomaly represents a more severe ossicular anomaly than is normally seen in congenital aural atresia, arising from an arrest earlier in the embryonic development of the first and second branchial arch. This has potentially important implications for surgical planning because hearing outcomes with placement of prosthesis may not be as good as with conventional atresia surgery, in which reconstruction is performed with the patient's native ossicular chain.

Dynamic CT for parathyroid disease: are multiple phases necessary?

BACKGROUND AND PURPOSE

A 4D CT protocol for detection of parathyroid lesions involves obtaining unenhanced, arterial, early, and delayed venous phase images. The aim of the study was to determine the ideal combination of phases that would minimize radiation dose without sacrificing diagnostic accuracy.

MATERIALS AND METHODS

With institutional review board approval, the records of 29 patients with primary hyperparathyroidism who had undergone surgical exploration were reviewed. Four neuroradiologists who were blinded to the surgical outcome reviewed the imaging studies in 5 combinations (unenhanced and arterial phase; unenhanced, arterial, and early venous; all 4 phases; arterial alone; arterial and early venous phases) with an interval of at least 7 days between each review. The accuracy of interpretation in lateralizing an abnormality to the side of the neck (right, left, ectopic) and localizing it to a quadrant in the neck (right or left upper, right or left lower) was evaluated.

RESULTS

The lateralization and localization accuracy (90.5% and 91.5%, respectively) of the arterial phase alone was comparable with the other combinations of phases. There was no statistically significant difference among the different combinations of phases in their ability to lateralize or localize adenomas to a quadrant (P = .976 and .996, respectively).

CONCLUSIONS

Assessment of a small group of patients shows that adequate diagnostic accuracy for parathyroid adenoma localization may be achievable by obtaining arterial phase images alone. If this outcome can be validated prospectively in a larger group of patients, then the radiation dose can potentially be reduced to one-fourth of what would otherwise be administered.

Imaging findings in MR imaging-guided focused ultrasound treatment for patients with essential tremor

BACKGROUND AND PURPOSE

MR imaging-guided focused sonography surgery is a new stereotactic technique that uses high-intensity focused sonography to heat and ablate tissue. The goal of this study was to describe MR imaging findings pre- and post-ventralis intermedius nucleus lesioning by MR imaging-guided focused sonography as a treatment for essential tremor and to determine whether there was an association between these imaging features and the clinical response to MR imaging-guided focused sonography.

MATERIALS AND METHODS

Fifteen patients with medication-refractory essential tremor prospectively gave consent; were enrolled in a single-site, FDA-approved pilot clinical trial; and were treated with transcranial MR imaging-guided focused sonography. MR imaging studies were obtained on a 3T scanner before the procedure and 24 hours, 1 week, 1 month, and 3 months following the procedure.

RESULTS

On T2-weighted imaging, 3 time-dependent concentric zones were seen at the site of the focal spot. The inner 2 zones showed reduced ADC values at 24 hours in all patients except one. Diffusion had pseudonormalized by 1 month in all patients, when the cavity collapsed. Very mild postcontrast enhancement was seen at 24 hours and again at 1 month after MR imaging-guided focused sonography. The total lesion size and clinical response evolved inversely compared with each other (coefficient of correlation = 0.29, P value = .02).

CONCLUSIONS

MR imaging-guided focused sonography can accurately ablate a precisely delineated target, with typical imaging findings seen in the days, weeks, and months following the treatment. Tremor control was optimal early when the lesion size and perilesional edema were maximal and was less later when the perilesional edema had resolved.

Dorsal thoracic arachnoid web and the "scalpel sign": a distinct clinical-radiologic entity

Arachnoid webs are intradural extramedullary bands of arachnoid tissue that can extend to the pial surface of the spinal cord, causing a focal dorsal indentation of the cord. These webs tend to occur in the upper thoracic spine and may produce a characteristic deformity of the cord that we term the "scalpel sign." We describe 14 patients whose imaging studies demonstrated the scalpel sign. Ten of 13 patients who underwent MR imaging demonstrated T2WI cord signal-intensity changes, and 7 of these patients also demonstrated syringomyelia adjacent to the level of indentation. Seven patients underwent surgery, with 5 demonstrating an arachnoid web as the cause of the dorsal indentation demonstrated on preoperative imaging. Although the webs themselves are rarely demonstrated on imaging, we propose that the scalpel sign is a reliable indicator of their presence and should prompt consideration of surgical lysis, which is potentially curative.

Utility of CT angiography in the identification and characterization of supraclinoid internal carotid artery blister aneurysms

BACKGROUND AND PURPOSE

Blister aneurysms of the supraclinoid ICA represent a rare but potentially catastrophic cause of SAH, often presenting both diagnostic and therapeutic dilemmas. We explore the utility of CTA in the identification and characterization of ICA blister aneurysms.

MATERIALS AND METHODS

We performed a retrospective review of catheter cerebral angiograms obtained at our institution over a 12-month period for evaluation of SAH, identifying 6 cases of ICA blister aneurysms. All patients underwent CTA and DSA for evaluation of SAH. The reports from the CTA and DSA studies were reviewed to identify aneurysms correctly diagnosed prospectively. Retrospective review of the CTA and DSA images was also performed. Review of the interpretations and images was performed for any follow-up studies.

RESULTS

All 6 patients presented with SAH, diagnosed by head CT. All patients subsequently underwent CTA prior to DSA evaluation. All 6 aneurysms were identified prospectively on initial DSA imaging. Of the 6 blister aneurysms, 4 (67%) were identified prospectively; and 5 (83%), retrospectively on CTA. All 6 patients underwent endovascular treatment with stent placement. Four of the 6 aneurysms underwent follow-up CTA (range, 9-22 days), including the 2 aneurysms that had been unidentifiable preprocedurally. All 4 blister aneurysms were seen postprocedurally by DSA. Three of these 4 (75%) residual aneurysms were detected by CTA (both prospectively and retrospectively).

CONCLUSIONS

In the presence of SAH and otherwise negative findings on CTA, a catheter cerebral angiogram should be performed to absolutely exclude an ICA blister aneurysm.

The evolution of the anatomically modern or advanced Homo sapiens: time, place, process, affinities and variations

This paper surveys the opinions expressed in the recent literature on the origins of the anatomically- modern Homo sapiens, and reviews the evidence from cranial and dental morphology argued by proponents of opposing views to support their case. It also critically analyses problems facing the interpretation of the evidence in arriving at a definitive conclusion to the debate.

The impact of expansive arterial remodeling on clinical presentation in carotid artery disease: a multidetector CT angiography study

BACKGROUND AND PURPOSE

Atherosclerotic arterial remodeling has been described in the coronary circulation but has not been studied extensively for carotid atherosclerosis. The purpose of our study was to examine the association between carotid artery remodeling and clinical presentation in patients with significant stenosis by using multidetector row CT (MDCT).

MATERIALS AND METHODS

One hundred eight patients with >or=50% stenosis (North American Symptomatic Carotid Endarterectomy Trial criteria) by MDCT angiography between January 2004 and June 2006 were identified. The study group included 37 symptomatic (65.9 +/- 13.0 years; 12 women; stenosis, 81.5 +/- 12.2%; 17 with stroke; 15 with transient ischemic attack; 5 with amaurosis fugax) and 71 asymptomatic patients (70.5 +/- 10.5 years; 28 women; stenosis, 78.8 +/- 11.1%). Remodeling ratio (RR) was calculated by dividing the outer vessel circumference at the site of greatest stenosis by a normal reference-segment vessel circumference. Maximum vessel thickness (MxVT) and eccentricity index (EI) of the plaque, defined as maximal thickness/minimal thickness at the site of greatest luminal narrowing, were also determined. Data were analyzed by using an independent t test.

RESULTS

The RR was significantly higher in symptomatic patients (1.64 +/- 0.44) than in asymptomatic patients (1.41 +/- 0.5) (P=.02). There was no significant difference in MxVT in symptomatic (5.9 +/- 2.1 mm) and asymptomatic patients (5.6 +/- 2.4 mm) (P=.45) and no significant difference in EI (symptomatic, 4.7 +/- 2.7; asymptomatic, 4.3 +/- 2.2; P=.38).

CONCLUSION

In this series of subjects with significant internal carotid artery stenosis, expansive carotid remodeling was significantly greater in patients with cerebral ischemic symptoms than in asymptomatic patients. The extent of expansive remodeling may indicate underlying atherosclerotic plaque vulnerability. MDCT has a role in the evaluation of carotid artery disease beyond examining luminal stenosis.

Extramedullary hematopoiesis involving the bilateral lacrimal fossae

Extramedullary hematopoiesis is a complication of a number of myeloproliferative disorders. MR imaging of the orbits was performed in a patient with bilateral orbital swelling with known myeloproliferative disorder and myelofibrosis. The study revealed symmetric, bilateral enhancing masses in the lacrimal fossae extending into the nasolacrimal ducts. Biopsy demonstrated sclerotic extramedullary hematopoietic tumor.

A novel dipyridodiazepinone inhibitor of HIV-1 reverse transcriptase acts through a nonsubstrate binding site

A novel dipyridodiazepinone, 6,11-dihydro-11-cyclopropyl-4-methyldipyrido[2,3-b:2',3'-e]- [1,4]diazepin-6-one (BI-RG-587), is a selective noncompetitive inhibitor of HIV-1 reverse transcriptase (RT-1). An azido photoaffinity analogue of BI-RG-587 was synthesized and found to irreversibly inhibit the enzyme upon UV irradiation. BI-RG-587 and close structural analogues competitively protected RT-1 from inactivation by the photoaffinity label. A thiobenzimidazolone (TIBO) derivative, a nonnucleoside inhibitor of RT-1, also protected the enzyme from photoinactivation, which suggests a common binding site for these compounds. Substrates dGTP, template-primer, and tRNA afforded no protection from enzyme inactivation. A tritiated photoaffinity probe was found to stoichiometrically and selectively label p66 such that 1 mol of probe inactivates 1 mol of RT-1.