Towards multicenter ß-amyloid PET imaging in mouse models: A triple scanner head-to-head comparison.

AIM: ß-amyloid (Aß) small animal PET facilitates quantification of fibrillar amyloidosis in Alzheimer's disease (AD) mouse models. Thus, the methodology is receiving growing interest as a monitoring tool in preclinical drug trials. In this regard, harmonization of data from different scanners at multiple sites would allow the establishment large collaborative cohorts and may facilitate efficacy comparison of different treatments. Therefore, we objected to determine the level of agreement of Aß-PET quantification by a head-to-head comparison of three different state-of-the-art small animal PET scanners, which could help pave the way for future multicenter studies. METHODS: Within a timeframe of 5 ± 2 weeks, transgenic APPPS1 (n = 9) and wild-type (WT) (n = 8) mice (age range: 13-16 months) were examined three times by Aß-PET ([18F]florbetaben) using a Siemens Inveon DPET, a MedisonanoScan PET/MR, and a MedisonanoScan PET/CT with harmonized reconstruction protocols. Cortex-to-white-matter 30-60 min p.i. standardized uptake value ratios (SUVRCTX/WM) were calculated to compare binding differences, effect sizes (Cohen's d) and z-score values of APPPS1 relative to WT mice. Correlation coefficients (Pearson's r) were calculated for the agreement of individual SUVR between different scanners. Voxel-wise analysis was used to determine the agreement of spatial pathology patterns. For validation of PET imaging against the histological gold standard, individual SUVR values were subject to a correlation analysis with area occupancy of methoxy­X04 staining. RESULTS: All three small animal PET scanners yielded comparable group differences between APPPS1 and WT mice (∆PET=20.4 % ± 2.9 %, ∆PET/MR=18.4 % ± 4.5 %, ∆PET/CT=18.1 % ± 3.3 %). Voxel-wise analysis confirmed a high degree of congruency of the spatial pattern (Dice coefficient (DC)PETvs.PET/MR=83.0 %, DCPETvs.PET/CT=69.3 %, DCPET/MRvs.PET/CT=81.9 %). Differences in the group level variance of the three scanners resulted in divergent z-scores (zPET=11.5 ± 1.6; zPET/MR=5.3 ± 1.3; zPET/CT=3.4 ± 0.6) and effect sizes (dPET=8.5, dPET/MR=4.5, dPET/CT=4.1). However, correlations at the individual mouse level were still strong between scanners (rPETvs.PET/MR=0.96, rPETvs.PET/CT=0.91, rPET/MRvs.PET/CT=0.87; all p ≤ 0.0001). Methoxy-X04 staining exhibited a significant correlation across all three PET machines combined (r = 0.76, p < 0.0001) but also at individual level (PET: r = 0.81, p = 0.026; PET/MR: r = 0.89, p = 0.0074; PET/CT: r = 0.93, p = 0.0028). CONCLUSIONS: Our comparison of standardized small animal Aß-PET acquired by three different scanners substantiates the possibility of moving towards a multicentric approach in preclinical AD research. The alignment of image acquisition and analysis methods achieved good overall comparability between data sets. Nevertheless, differences in variance of sensitivity and specificity of different scanners may limit data interpretation at the individual mouse level and deserves methodological optimization.

Uniportal Thoracoscopic Complex Combined Seg-Sub-subsegmentectomy of RS9+10bii: Dual-Display Method and Combined Approaches (Trans-fissure and Trans-ligament).

BACKGROUND: Uniportal thoracoscopic lateral basal segmentectomy is the most technically challenging anatomic segmentectomy,1-3 especially when it involves combined subsegmentectomy or sub-subsegmentectomy. Therefore, there are very few reports detailing its technical aspect. PATIENT AND METHOD: In this multimedia article, we describe a very complex uniportal thoracoscopic combined seg-sub-subsegmentectomy of RS9+10bii through the oblique fissure approach and the inferior pulmonary ligament approach, following a single-direction strategy4,5 to advance the procedure, utilizing the stem-branch method3,6 for segmental/subsegmental/sub-subsegmental structure tracking, and employing dual-display method, which comprises the intravenous ICG injection method and the inflation/deflation method, to identify intersegmental and inter-seg-sub-subsegmental planes. RESULTS: The operation lasted 169 min, with approximately 20 mL of blood loss. The patient experienced an active hemothorax and two spontaneous pneumothoraxes on postoperative days 1, 4, and 19, respectively, all of which resolved promptly after treatment. Histopathological examination of the specimen documented invasive non-mucinous adenocarcinoma with negative surgical margins and lymph nodes. The staging was determined as pT1bN0M0, stage IA2. During the 14-month follow-up period, there were no signs of tumor recurrence or metastasis observed. The FVC, FEV1, and FEV1%pred decreased by 11.9%, 12.5%, and 12.8%, respectively, at postoperative month 6. CONCLUSIONS: Complex basal segmentectomies, which necessitate combined subsegmental or sub-subsegmental resections, such as RS9+10bii, are feasible using the dual-display and combined approaches method. This method simplifies the steps of the very complex combined subsegmentectomy, averting the need for extensive lung resection. In addition, when performing these combined segmentectomies, precise anatomical dissection is crucial to prevent complications such as minor bronchopleural fistulas.

Optimal vaccination strategies for imperfect vaccines and variable host susceptibility.

I present a method to allocate a given number of vaccines to members of a population who differ in their susceptibility to the disease so that the final size of the epidemic is minimised. I consider an arbitrary distribution of protection that the vaccine confers, including the extreme cases of leaky and all-or-none vaccines. The optimal vaccination policy depends on the distribution of protection. While for low values of the basic reproduction number R0 the optimal policy prioritises the most susceptible hosts, I show that for almost any distribution the order of priority reverses and the least susceptible hosts should be vaccinated when R0 is high. The exception where this does not happen is the all-or-none vaccine. However, even a small deviation from the ideal all-or-none distribution can imply that the limited number of vaccines should be given to less susceptible hosts already at realistic values of R0.

Clinical Use of Trabecular Bone Score: The 2023 ISCD Official Positions.

Osteoporosis can currently be diagnosed by applying the WHO classification to bone mineral density (BMD) assessed by dual-energy x-ray absorptiometry (DXA). However, skeletal factors other than BMD contribute to bone strength and fracture risk. Lumbar spine TBS, a grey-level texture measure which is derived from DXA images has been extensively studied, enhances fracture prediction independent of BMD and can be used to adjust fracture probability from FRAX® to improve risk stratification. The purpose of this International Society for Clinical Densitometry task force was to review the existing evidence and develop recommendations to assist clinicians regarding when and how to perform, report and utilize TBS. Our review concluded that TBS is most likely to alter clinical management in patients aged ≥ 40 years who are close to the pharmacologic intervention threshold by FRAX. The TBS value from L1-L4 vertebral levels, without vertebral exclusions, should be used to calculate adjusted FRAX probabilities. L1-L4 vertebral levels can be used in the presence of degenerative changes and lumbar compression fractures. It is recommended not to report TBS if extreme structural or pathological artifacts are present. Monitoring and reporting TBS change is unlikely to be helpful with the current version of the TBS algorithm. The next version of TBS software will include an adjustment based upon directly measured tissue thickness. This is expected to improve performance and address some of the technical factors that affect the current algorithm which may require modifications to these Official Positions as experience is acquired with this new algorithm.

Know the resident: Unlocking value and positive outcomes in assisted living nursing.

None.

Liposomal doxorubicin and free doxorubicin in vivo quantitation method developed on CE-LIF and its application in pharmacokinetic analysis.

As a novel drug delivery system, liposomes were used to improve pharmacokinetics/pharmacodynamics (PK/PD) characters, minimize toxicity, and enhance drug-target selectivity. However, heterogeneity of drug releasing process and liposome itself challenged traditional pharmaceutical analytical techniques, especially in vivo pharmacokinetic studies. In this study, a novel liposomal doxorubicin (L-DOX) pharmacokinetic analysis strategy was developed with capillary electrophoresis coupled with laser-induced fluorescence (CE-LIF) detector. The background electrolyte (BGE) system was composed of borate and sodium dodecyl sulfate (SDS), which was optimized to successfully achieve simultaneous online separation and quantitative analysis of free DOX and liposome-encapsulated DOX. The method was applied to the in vivo pharmacokinetic study of L-DOX in rats. The results showed that the concentration of total DOX (T-DOX) was gradually decreasing, while the concentration of L-DOX was relatively stable, with a concentration of 31.6 ± 4.8 µg/mL within 24 h. It was the first time to achieve liposomal drugs in vivo analysis with CE-LIF. CE-LIF was proved as potential rapidly real-time analytical methods for liposomal drugs in vivo occurrence monitoring.

The Origin and Fate of Chondrocytes: Cell Plasticity in Physiological Setting.

PURPOSE OF REVIEW: Here, we discuss the origin of chondrocytes, their destiny, and their plasticity in relationship to bone growth, articulation, and formation of the trabeculae. We also consider these processes from a biological, clinical, and evolutionary perspective. RECENT FINDINGS: Chondrocytes, which provide the template for the formation of most bones, are responsible for skeletal growth and articulation during postnatal life. In recent years our understanding of the fate of these cells has changed dramatically. Current evidence indicates a paradoxical situation during skeletogenesis, with some cells of mesenchymal condensation differentiating directly into osteoblasts, whereas others of the same kind give rise to highly similar osteoblasts via a complex process of differentiation involving several chondrocyte intermediates. The situation becomes even more paradoxical during postnatal growth when stem cells in the growth plate produce differentiated, functional progenies, which thereafter presumably dedifferentiate into another type of stem cell. Such a remarkable transition from one cell type to another under postnatal physiological conditions provides a fascinating example of cellular plasticity that may have valuable clinical implications.

NN-LCS: Neural Network and Linear Coordinate Solver Fusion Method for UWB Localization in Car Keyless Entry System.

Nowadays, ultra-wideband (UWB) technology is becoming a new approach to localize keyfobs in the car keyless entry system (KES), because it provides precise localization and secure communication. However, for vehicles the distance ranging suffers from great errors because of none-line-of-sight (NLOS) which is raised by the car. Regarding the NLOS problem, efforts have been made to mitigate the point-to-point ranging error or to estimate the tag coordinate by neural networks. However, it still suffers from some problems such as low accuracy, overfitting, or a large number of parameters. In order to address these problems, we propose a fusion method of a neural network and linear coordinate solver (NN-LCS). We use two FC layers to extract the distance feature and received signal strength (RSS) feature, respectively, and a multi-layer perceptron (MLP) to estimate the distances with the fusion of these two features. We prove that the least square method which supports error loss backpropagation in the neural network is feasible for distance correcting learning. Therefore, our model is end-to-end and directly outputs the localization results. The results show that the proposed method is high-accuracy and with small model size which could be easily deployed on embedded devices with low computing ability.

Analysis and Design of a CLC/N Compensated CC-Type WPT System with Compact and Low-Cost Receiver.

Wireless power transfer (WPT) has been extensively studied by technicians for its advantages of safety, convenience and aesthetics. The load-independent constant current (CC) output is the focus of WPT research and has been initially applied in various fields, such as light-emitting diodes (LEDs) driving, CC charging of electric vehicles (EVs), etc. However, the existing CC-type WPT system has problems in that the output current is constrained by the loosely coupled transformer (LCT) parameters, the receiver is bulky, and the development cost is high. Therefore, this manuscript proposes a new CLC/None (CLC/N) compensated WPT system with a CC output function that eliminates the receiver-side compensation components, ensures the compactness of the receiver, and saves on production costs. The conditions for satisfying the CC output and zero-phase-angle (ZPA) operation of the proposed system are first discussed. Then, the detailed parameter design method is provided, and the characteristic that the output current is unconstrained by the LCT parameters is illustrated. In addition, the implementation of zero-voltage switching (ZVS) operation of the proposed system and the sensitivity of the changes of compensation components to the output current are analyzed in detail. Furthermore, to demonstrate the superiority of the proposed system, several other typical CC-type WPT systems are introduced for comparison. Finally, a confirmatory experimental prototype with an output current of 2 A is fabricated, and the experimental results are consistent with the theoretical analysis.

Overwhelmed: a Dementia Caregiver Vital Sign.

BACKGROUND: The emotional stress of caring for someone with Alzheimer's disease and related dementias is high and results in adverse effects on caregivers and the persons living with disease. In preliminary work, caregiver reports of regularly feeling "completely overwhelmed" were associated with lack of measurable clinical benefit from a comprehensive dementia care program. OBJECTIVE: To examine the sociodemographic and clinical characteristics of all caregivers who felt overwhelmed at entry into a comprehensive dementia care program, the trajectory of this symptom over 1 year, and its predictive value for 1-year caregiver outcomes. DESIGN: Longitudinal cohort study SETTING: Academic health center PARTICIPANTS: Caregivers of patients enrolled in a comprehensive dementia care program EXPOSURES: Caregiver report of feeling "completely overwhelmed" at baseline MAIN MEASURES: Caregiver report of feeling "completely overwhelmed" at baseline and 1 year, and validated scales of caregiver strain, distress, depressive symptoms, burden, mortality, and long-term nursing home placement KEY RESULTS: Compared to caregivers who were not overwhelmed, overwhelmed caregivers had more distress from behavioral symptoms of the person living with dementia, worse depression scores, and higher composite dementia burden scores at baseline. They also had worse depressive symptoms, strain, and composite burden scores at 1 year, after adjustment for baseline scores. Having an overwhelmed caregiver did not predict long-term nursing home placement or mortality among persons with dementia. CONCLUSIONS: A single question about whether a caregiver is overwhelmed might indicate caregivers who have considerable current and future symptom burden and who may benefit from increased support and resources.

Quantification of Serum Exosome Biomarkers Using 3D Nanoporous Gold and Spectrophotometry.

Tumor-derived exosomes may provide biomarkers for cancer treatment. Using sputtering technology, an affinity-based device to capture exosomes was developed using nanoporous substrate (NPG)-coated silicon microscopy. Immunology-based techniques detect and purify exosomes using gold coating with a specific antigen. Inverted fluorescent microscopy was used to detect target exosomes quantitatively utilizing fluorescent nanospheres as the label. We quantified the expression of CD63 surface protein markers on exosomes from conditioned culture media of breast cancer cells. The exosomes that targeted specific proteins with controls were statistically analyzed and compared to those that targeted non-specific proteins. Results from SEM showed that the exosomes were circular, between 30 and 150 nanometers in size. The porous gold substrates captured more exosomes than the nonporous substrates. Nitric acid treatments at different times resulted in a variety of pore sizes. Despite the increase in the size of the pores, the number of exosomes found in the porous gold substrate treated for 10 min nearly doubled compared to the one treated for 5 min. In this work, a fluorescence biosensor was developed to detect breast cancer exosomes using nanoporous gold substrates (NPG). Assay and model exosomes of specific breast cancer cells showed that exosomes exhibit diagnostic surface protein markers, reflecting the protein profile of their parent cells. Furthermore, the specific binding between the exosome surface antibodies and the targets identified the CD63 biomarkers on the exosome, suggesting these markers' diagnostic potential. This study can accelerate exosome research in determining tumor-related exosomes and develop novel cancer diagnostic methods.

Long-term prognostic outcomes and implication of oral anticoagulants in patients with new-onset atrial fibrillation following st-segment elevation myocardial infarction.

BACKGROUND: New-onset atrial fibrillation (NEW-AF) following ST-segment elevation myocardial infarction (STEMI) is a common complication, but the true prognostic impact of NEW-AF is unknown. Additionally, the optimal treatment of NEW-AF among patients with STEMI is warranted. METHODS: A large cohort of consecutive patients with STEMI treated with percutaneous coronary intervention were identified using the Eastern Danish Heart Registry from 1999-2016. Medication and end points were retrieved from Danish nationwide registries. NEW-AF was defined as a diagnosis of AF within 30 days following STEMI. Patients without a history of AF and alive after 30 days after discharge were included. Incidence rates were calculated and multivariate analyses performed to determine the association between NEW-AF and long-term mortality, incidence of ischemic stroke, re-MI, and bleeding leading to hospitalization, and the comparative effectiveness of OAC therapy on these outcomes. RESULTS: Of 7944 patients with STEMI, 296 (3.7%) developed NEW-AF. NEW-AF was associated with increased long-term mortality (adjusted HR 1.48, 95% CI 1.20-1.82, P<.001) and risk of bleeding leading to hospitalization (adjusted HR 1.36, 95% CI 1.00-1.85, P=.050), and non-significant increased risk of ischemic stroke (adjusted HR 1.45, 95% CI 0.96-2.19, P=.08) and re-MI (adjusted HR 1.14, 95% CI 0.86-1.52, P=.35) with a median follow-up of 5.8 years. In NEW-AF patients, 38% received OAC therapy, which was associated with reduced long-term mortality (adjusted HR 0.69, 95% CI 0.47-1.00, P=.049). CONCLUSIONS: NEW-AF following STEMI is associated with increased long-term mortality. Treatment with OAC therapy in NEW-AF patients is associated with reduced long-term mortality.

Pre-operative atrial fibrillation and early right ventricular failure after left ventricular assist device implantation: a systematic review and meta-analysis.

BACKGROUND: Right ventricular failure (RVF) remains a major cause of morbidity and mortality after left ventricular assist device (LVAD). Atrial fibrillation (AF) is known for its deleterious effects on cardiac function and hemodynamics. The association of pre-operative AF with the risk of early post-LVAD RVF has not been well described. METHOD: A comprehensive literature search was performed through April, 9 2021. Cohort studies comparing the risk of post-operative RVF and/or need for right ventricular assist device (RVAD) after LVAD in patients with or without AF were included. Pooled odds ratio (OR) with 95% confidence intervals (CI) and I2 statistic were calculated using the random-effects model. RESULTS: Six studies were included in the analysis. Post-operative RVF was reported in 5 studies (1,841 patients) and RVAD use was reported in 4 studies (1,355 patients). There is a non-significant trend toward a higher risk of post-operative RVF in the AF group (pooled OR=1.25, 95%CI=0.99-1.58). No significant association between AF and RVAD use is noted (pooled OR=1.17, 95%CI=0.82-1.66). CONCLUSIONS: Pre-operative AF is not significantly associated with higher risks of post-operative RVF and RVAD use after LVAD implantation, although the trend toward higher post-operative RVF is observed in patients with pre-operative AF. Additional research using a larger study population is warranted to better understand the association of pre-operative AF and the development of post-LVAD RVF.

Predictive Model-Driven Hotspotting to Decrease Emergency Department Visits: a Randomized Controlled Trial.

BACKGROUND: Emergency department (ED) visits contribute substantially to health care expenditures. Case management has been proposed as a strategy to address the medical and social needs of complex patients. However, strong research designs to evaluate the effectiveness of such interventions are limited. OBJECTIVES: To evaluate whether a community-based case management program was associated with reduced ED utilization among complex patients. DESIGN: Patients whose risk exceeded a threshold were randomly assigned to a group offered case management or to the control group. Assignment occurred at five intervals between November 2017 and January 2019. Program effectiveness for all assigned patients was assessed using an intention-to-treat effect. Program effectiveness among those who received treatment was assessed using a local average treatment effect, estimated using instrumental variables. Both estimators were adjusted for baseline characteristics using linear models. PARTICIPANTS: Adults over age 18 with at least one health care encounter with Michigan Medicine or St. Joseph Mercy Health System between June 2, 2016, and November 27, 2018. INTERVENTIONS: Intervention arm participants (n = 486) were offered coordinated case management across medical, mental health, and social service organizations. Control arm participants (n = 409) received usual care. MAIN MEASURES: The primary outcome was the number of ED visits in the 6 months following randomization into the study. Secondary outcomes were 6-month counts of inpatient and outpatient visits. KEY RESULTS: Of the 486 patients assigned to the intervention, 131 (27%) consented to receive case management. The intention-to-treat effect on ED visits was + 0.14 (95% CI: - 0.27 to + 0.55). The local average treatment effect among those who consented and received case management was + 0.53 (95% CI: - 1.00 to + 2.05). Intention-to-treat and local average treatment effects were not significant for secondary outcomes. CONCLUSIONS: The community case management intervention targeting ED visits was not associated with reduced utilization. Future case management interventions may benefit from additional patient engagement strategies and longer evaluation time periods. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT03293160.

Validation of quantitative measure of repolarization reserve as a novel marker of drug induced proarrhythmia.

Repolarization reserve, the robustness of a cell to repolarize even when one of the repolarization mechanisms is failing, has been described qualitatively in terms of ionic currents, but has not been quantified by a generic metric that is applicable to drug screening. Prolonged repolarization leading to repolarization failure is highly arrhythmogenic. It may lead to ventricular tachycardia caused by triggered activity from early afterdepolarizations (EADs), or it may promote the occurrence of unidirectional conduction block and reentry. Both types of arrhythmia may deteriorate into ventricular fibrillation (VF) and death. We define the Repolarization Reserve Current (RRC) as the minimum constant current necessary to prevent normal repolarization of a cell. After developing and testing RRC for nine computational ionic models of various species, we applied it experimentally to atrial and ventricular human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM), and isolated guinea-pig ventricular cardiomyocytes. In simulations, repolarization was all-or-none with a precise, model-dependent critical RRC, resulting in a discrete shift in the Action Potential Duration (APD) - RRC relation, in the occurrence of EADs and repolarization failure. These data were faithfully reproduced in cellular experiments. RRC allows simple, fast, unambiguous quantification of the arrhythmogenic propensity in cardiac cells of various origins and species without the need of prior knowledge of underlying currents and is suitable for high throughput applications, and personalized medicine applications.

How "none of the above" (NOTA) affects the accessibility of tested and related information in multiple-choice questions.

Answering multiple-choice questions increases accessibility of the tested information and can improve accessibility of related information. However, multiple-choice questions with "none of the above" (NOTA) as a choice hurts accessibility of the previously tested information when NOTA serves as the correct answer (NOTAcorrect). Would prompting participants to recall an answer when choosing NOTA, and then providing feedback, reduce the costs of NOTAcorrect items? In the present experiments, participants answered general knowledge questions in multiple-choice (with a NOTA alternative) or cued-recall formats; half of the participants, when choosing NOTA, were prompted to provide an answer. Half of the participants received feedback. On a final cued-recall test assessing performance for previously tested and nontested related information, we found that NOTAcorrect questions hurt performance for previously tested items as compared to the cued-recall condition; but they facilitated recall of related information. Feedback improved performance for all previously tested information, but performance was still worse for NOTAcorrect questions than for cued-recall questions. The addition of a cued-recall component on NOTA questions did not influence accessibility. The results have implications for using NOTA in practice tests and help explain why using NOTAcorrect items hurt learning, even with feedback, supporting a proactive interference account.

Lord Adrian, MD, PRS, OM.

Edgar Douglas Adrian was an outstandingly brilliant, Nobel prize-winning neurophysiologist. He is remembered for developing the all-or-none principle of muscle contraction, and for explaining the minutiae of motor and sensory nerve transmission. He showed that the afferent effect in a neuron depends on the pattern in time of the impulses travelling in it, thereby providing a quantitative basis of nervous behaviour. With Sir Charles Sherrington, he was awarded the Nobel Prize in 1932 for discoveries on the functions of the neurons.

Cardiac action potential repolarization revisited: early repolarization shows all-or-none behaviour.

In healthy mammalian hearts the action potential (AP) waveform initiates and modulates each contraction, or heartbeat. As a result, AP height and duration are key physiological variables. In addition, rate-dependent changes in ventricular AP duration (APD), and variations in APD at a fixed heart rate are both reliable biomarkers of electrophysiological stability. Present guidelines for the likelihood that candidate drugs will increase arrhythmias rely on small changes in APD and Q-T intervals as criteria for safety pharmacology decisions. However, both of these measurements correspond to the final repolarization of the AP. Emerging clinical evidence draws attention to the early repolarization phase of the action potential (and the J-wave of the ECG) as an additional important biomarker for arrhythmogenesis. Here we provide a mechanistic background to this early repolarization syndrome by summarizing the evidence that both the initial depolarization and repolarization phases of the cardiac action potential can exhibit distinct time- and voltage-dependent thresholds, and also demonstrating that both can show regenerative all-or-none behaviour. An important consequence of this is that not all of the dynamics of action potential repolarization in human ventricle can be captured by data from single myocytes when these results are expressed as 'repolarization reserve'. For example, the complex pattern of cell-to-cell current flow that is responsible for AP conduction (propagation) within the mammalian myocardium can change APD and the Q-T interval of the electrocardiogram alter APD stability, and modulate responsiveness to pharmacological agents (such as Class III anti-arrhythmic drugs).

Increased mercury emissions from modern dental amalgams.

All types of dental amalgams contain mercury, which partly is emitted as mercury vapor. All types of dental amalgams corrode after being placed in the oral cavity. Modern high copper amalgams exhibit two new traits of increased instability. Firstly, when subjected to wear/polishing, droplets rich in mercury are formed on the surface, showing that mercury is not being strongly bonded to the base or alloy metals. Secondly, high copper amalgams emit substantially larger amounts of mercury vapor than the low copper amalgams used before the 1970s. High copper amalgams has been developed with focus on mechanical strength and corrosion resistance, but has been sub-optimized in other aspects, resulting in increased instability and higher emission of mercury vapor. This has not been presented to policy makers and scientists. Both low and high copper amalgams undergo a transformation process for several years after placement, resulting in a substantial reduction in mercury content, but there exist no limit for maximum allowed emission of mercury from dental amalgams. These modern high copper amalgams are nowadays totally dominating the European, US and other markets, resulting in significant emissions of mercury, not considered when judging their suitability for dental restoration.

Tunable recombinant protein expression in E. coli: promoter systems and genetic constraints.

Tuning of transcription is a promising strategy to overcome challenges associated with a non-suitable expression rate like outgrowth of segregants, inclusion body formation, metabolic burden and inefficient translocation. By adjusting the expression rate-even on line-to purposeful levels higher product titres and more cost-efficient production processes can be achieved by enabling culture long-term stability and constant product quality. Some tunable systems are registered for patents or already commercially available. Within this contribution, we discuss the induction mechanisms of various Escherichia coli inherent promoter systems with respect to their tunability and review studies using these systems for expression tuning. According to the current level of knowledge, some promoter systems were successfully used for expression tuning, and in some cases, analytical evidence on single-cell level is still pending. However, only a few studies using tunable strains apply a suitable process control strategy. So far, expression tuning has only gathered little attention, but we anticipate that expression tuning harbours great potential for enabling and optimizing the production of a broad spectrum of products in E. coli.