Analysis of seizure-cluster circadian periodicity from a long-term, open-label safety study of diazepam nasal spray

OBJECTIVE

Seizure clusters require prompt medical treatment to minimize possible progression to status epilepticus, increased health care use, and disruptions to daily life. Isolated seizures may exhibit cyclical patterns, including circadian and longer rhythms. However, little is known about the cyclical patterns in seizure clusters. This post hoc analysis of data from a long-term, phase 3, open-label, repeat-dose safety study of diazepam nasal spray modeled the periodicity of treated seizure clusters.

METHODS

Mixed-effects cosinor analysis evaluated circadian rhythmicity, and single component cosinors using 12 and 24 h were used to calculate cosinor parameters (e.g., midline statistic of rhythm, wave ampitude, and acrophase [peak]). Analysis was completed for the full cohort and a consistent cohort of participants with two or more seizure clusters in each of four, 3-month periods. The influence of epilepsy type on cosinor parameters was also analyzed.

RESULTS

Seizure-cluster events plotted across 24 h showed a bimodal distribution with acrophases (peaks) at ~06:30 and ~18:30. A 12-h plot showed a single peak at ~06:30. Cosinor analyses of the full and consistent cohort aligned, with acrophases for both models predicting peak seizure activity at ~23:30 on a 24-h scale and ~07:30 on a 12-h scale. The consistent cohort was associated with increases in baseline and peak seizure-cluster activity. Analysis by epilepsy type identified distinct trends. Seizure clusters in the focal epilepsy group peaked in the evening (acrophase 19:19), whereas events in the generalized epilepsy group peaked in the morning (acrophase 04:46). Together they compose the bimodal clustering observed over 24 h.

SIGNIFICANCE

This analysis of seizure clusters treated with diazepam nasal spray demonstrated that seizure clusters occur cyclically in 12- and 24-h time frames similar to that reported with isolated seizures. Further elucidation of these patterns may provide important information for patient care, ranging from improved patient-centered outcomes to seizure-cluster prediction.

Spread of the cycles: a feedback perspective on the Anthropocene

What propelled the human 'revolutions' that started the Anthropocene? and what could speed humanity out of trouble? Here, we focus on the role of reinforcing feedback cycles, often comprised of diverse, unrelated elements (e.g. fire, grass, humans), in propelling abrupt and/or irreversible, revolutionary changes. We suggest that differential 'spread of the cycles' has been critical to the past human revolutions of fire use, agriculture, rise of complex states and industrialization. For each revolution, we review and map out proposed reinforcing feedback cycles, and describe how new systems built on previous ones, propelling us into the Anthropocene. We argue that to escape a bleak Anthropocene will require abruptly shifting from existing unsustainable 'vicious cycles', to alternative sustainable 'virtuous cycles' that can outspread and outpersist them. This will need to be complemented by a revolutionary cultural shift from maximizing growth to maximizing persistence (sustainability). To achieve that we suggest that non-human elements need to be brought back into the feedback cycles underlying human cultures and associated measures of progress. This article is part of the theme issue 'Evolution and sustainability: gathering the strands for an Anthropocene synthesis'.

The Wave Model of Sleep Dynamics and an Invariant Relationship between NonREM and REM Sleep

Explaining the complex structure and dynamics of sleep, which consist of alternating and physiologically distinct nonREM and REM sleep episodes, has posed a significant challenge. In this study, we demonstrate that a single-wave model concept captures the distinctly different overnight dynamics of the four primary sleep measures-the duration and intensity of nonREM and REM sleep episodes-with high quantitative precision for both regular and extended sleep. The model also accurately predicts how these polysomnographic measures respond to sleep deprivation or abundance. Furthermore, the model passes the ultimate test, as its prediction leads to a novel experimental finding-an invariant relationship between the duration of nonREM episodes and the intensity of REM episodes, the product of which remains constant over consecutive sleep cycles. These results suggest a functional unity between nonREM and REM sleep, establishing a comprehensive and quantitative framework for understanding normal sleep and sleep disorders.

Impacts of additional cycles of neoadjuvant immunotherapy on surgery in non-small-cell lung cancer

OBJECTIVE

Whether cycle number influences the subsequent pathological or surgical outcomes remained unclear. This study aimed to assess the efficacy and surgical safety of neoadjuvant immunochemotherapy-based treatment in the real-world setting.

METHODS

Clinical data of patients who received neoadjuvant immunochemotherapy for non-small-cell lung cancer between 2018 and 2021 were collected. Oncological outcomes such as objective response rate (ORR), major pathological response (MPR), and pathological complete response (pCR), and surgical outcomes including operating time, intraoperative bleeding, postoperative drainage, and hospital stay were analyzed.

RESULTS

In total, 176 patients were included, among whom 102 cases were lung squamous carcinoma (LUSQ). After immunochemotherapy, 98 (56%) of patients achieved ORR. Notably, the ORR (63% vs. 46%, p = 0.039) and pCR (45% vs. 27%, p = 0.022) were significantly higher in patients with LUSQ. For patients who received two, three, four, and five or more cycles, the ORRs were 52%, 67%, 53%, and 50% (p = 0.36). In post hoc analysis, cycle numbers showed no significant association with MPR or pCR (p = 0.14 and p = 0.073). Treatment cycles showed no influence on operating time, postoperative drainage, and hospital stay (p = 0.79, 0.37, and 0.22). Notably, the blood loss index of patients who received more than four cycles was higher than those receiving four or fewer cycles (mean blood loss: two or fewer cycles 153.1, three cycles 113.8, four cycles 137.6, and five or more cycles 293.3, respectively).

CONCLUSIONS

This study indicated that cycles of neoadjuvant immunochemotherapy had no significant effect on the feasibility and safety of surgery. Although not statistically significant, patients who received five or more cycles of treatment experienced higher intraoperative blood loss.

Durability and Degradation Mechanisms of Antifrosting Surfaces

Rapid implementation of renewable energy technologies has exacerbated the potential for economic loss and safety concerns caused by ice and frost accretion, which occurs on the surfaces of wind turbine blades, photovoltaic panels, and residential and electric vehicle air-source heat pumps. The past decade has seen advances in surface chemistry and micro- and nanostructures that can promote passive antifrosting and enhance defrosting. However, the durability of these surfaces remains the major obstacle preventing real-life applications, with degradation mechanisms remaining poorly understood. Here, we conducted durability tests on antifrosting surfaces, including superhydrophobic, hydrophobic, superhydrophilic, and slippery liquid-infused surfaces. For superhydrophobic surfaces, we demonstrate durability with progressive degradation for up to 1000 cycles of atmospheric frosting-defrosting and month-long outdoor exposure tests. We show that progressive degradation, as reflected by increased condensate retention and reduced droplet shedding, results from molecular-level degradation of the low-surface-energy self-assembled monolayer (SAM). The degradation of the SAM leads to local high-surface-energy defects, which further deteriorate the surface by promoting accumulation of atmospheric particulate matter during cyclic condensation, frosting, and melt drying. Furthermore, cyclic frosting and defrost tests demonstrate the durability and degradation mechanisms of other surfaces to show, for example, the loss of water affinity of superhydrophilic surfaces after 22 days due to atmospheric volatile organic compound (VOC) adsorption and significant lubricant drainage for lubricant-infused surfaces after 100 cycles. Our work reveals the degradation mechanism of functional surfaces during exposure to long-term frost-defrost cycling and elucidates guidelines for the development of future surfaces for real-life antifrosting/icing applications.

Twenty-Five Years of PSP Toxicity in Galician (NW Spain) Bivalves: Spatial, Temporal, and Interspecific Variations

Twenty-five years of paralytic shellfish poisoning (PSP) toxicity in Galician bivalves have been studied. PSP was detected in 4785 out of 73,740 samples of the commercially important bivalve species analyzed from 1995 to 2020. Its general prevalence in the area was 6.5%. Only 1.6% of all samples tested were over the regulatory limit (incidence). The maximum level of PSP in the area, 40,800 µg STX 2HCl-eq kg^-1, was recorded in raft mussels from Bueu (PON-II, Pontevedra) in December 2005. The highest maximum PSP values were found in mussels, which were mostly affected by Gymnodinium catenatum, but not those of prevalence and incidence which were recorded in clams, mostly affected by Alexandrium. Average levels in mussels were higher than in any other studied species. Spatially, in general, the prevalence, incidence, maximum, and average PSP toxicity during episodes tend to decrease from south to northeast, but some hot points with high levels can be identified. PCA analysis separates the southern rías, associated to G. catenatum blooms, from the middle and northern ones, associated to Alexandrium blooms. Along the year, two main peaks of the four variables are observed, the first one in late autumn-winter and the other in summer, the summer peak being much more important for the infaunal species than for raft mussels. In the seasonal pattern obtained by time series analysis of the average PSP toxicity, the autumn-winter peak was only maintained (and very reduced) in the southern rías, indicating that this peak is seasonally much less important than the summer peak. The observed seasonality is expected based on the timing of the blooms of the two PSP-producing phytoplankton groups present in the area. Over the 25 years of monitoring, large differences in PSP toxicity have been observed. Apart from some special years, an ascending trend in prevalence and incidence seems to be present from 2011 to 2020. No trend seems to exist during the same period for average or maximum toxicity.

Intergenerational genotypic interactions drive collective behavioural cycles in a social insect

Many social animals display collective activity cycles based on synchronous behavioural oscillations across group members. A classic example is the colony cycle of army ants, where thousands of individuals undergo stereotypical biphasic behavioural cycles of about one month. Cycle phases coincide with brood developmental stages, but the regulation of this cycle is otherwise poorly understood. Here, we probe the regulation of cycle duration through interactions between brood and workers in an experimentally amenable army ant relative, the clonal raider ant. We first establish that cycle length varies across clonal lineages using long-term monitoring data. We then investigate the putative sources and impacts of this variation in a cross-fostering experiment with four lineages combining developmental, morphological and automated behavioural tracking analyses. We show that cycle length variation stems from variation in the duration of the larval developmental stage, and that this stage can be prolonged not only by the clonal lineage of brood (direct genetic effects), but also of the workers (indirect genetic effects). We find similar indirect effects of worker line on brood adult size and, conversely (but more surprisingly), indirect genetic effects of the brood on worker behaviour (walking speed and time spent in the nest).

Fluctuations in EEG band power at subject-specific timescales over minutes to days explain changes in seizure evolutions

Epilepsy is recognised as a dynamic disease, where both seizure susceptibility and seizure characteristics themselves change over time. Specifically, we recently quantified the variable electrographic spatio-temporal seizure evolutions that exist within individual patients. This variability appears to follow subject-specific circadian, or longer, timescale modulations. It is therefore important to know whether continuously recorded interictaliEEG features can capture signatures of these modulations over different timescales. In this study, we analyse continuous intracranial electroencephalographic (iEEG) recordings from video-telemetry units and find fluctuations in iEEG band power over timescales ranging from minutes up to 12 days. As expected and in agreement with previous studies, we find that all subjects show a circadian fluctuation in their iEEG band power. We additionally detect other fluctuations of similar magnitude on subject-specific timescales. Importantly, we find that a combination of these fluctuations on different timescales can explain changes in seizure evolutions in most subjects above chance level. These results suggest that subject-specific fluctuations in iEEG band power over timescales of minutes to days may serve as markers of seizure modulating processes. We hope that future study can link these detected fluctuations to their biological driver(s). There is a critical need to better understand seizure modulating processes, as this will enable the development of novel treatment strategies that could minimise the seizure spread, duration or severity and therefore the clinical impact of seizures.

Twenty-Five Years of Domoic Acid Monitoring in Galicia (NW Spain): Spatial, Temporal and Interspecific Variations

Prevalence, impact on shellfish resources and interspecific, spatial, and temporal variabilities of domoic acid (DA) in bivalves from Galicia (NW Spain) have been studied based on more than 25 years of monitoring data. The maximum prevalence (samples in which DA was detected) (100%) and incidence (samples with DA levels above the regulatory limit) (97.4%) were recorded in Pecten maximus, and the minimum ones in Mytilus galloprovincialis (12.6 and 1.1%, respectively). The maximum DA concentrations were 663.9 mg kg-1 in P. maximus and 316 mg kg-1 in Venerupis corrugata. After excluding scallop P. maximusdata, DA was found (prevalence) in 13.3% of bivalve samples, with 1.3% being over the regulatory limit. In general, the prevalence of this toxin decreased towards the North but not the magnitude of its episodes. The seasonal distribution was characterized by two maxima, in spring and autumn, with the later decreasing in intensity towards the north. DA levels decreased slightly over the studied period, although this decreasing trend was not linear. A cyclic pattern was observed in the interannual variability, with cycles of 4 and 11 years. Intoxication and detoxification rates were slower than those expected from laboratory experiments, suggesting the supply of DA during these phases plays an important role.

What is the optimal number of neoadjuvant chemotherapy cycles for resectable colorectal liver oligometastases?

Background

The optimal number of neoadjuvant chemotherapy (NAC) cycles for resectable colorectal liver oligometastases (CLOM) remains unclear. The aim of this study was to investigate the optimal number of NAC cycles.

Methods

One hundred twenty-nine consecutive patients were included in this study. X-tile analysis was implemented to investigate the optimal cut-off point for NAC cycles. Propensity score matching was performed to reduce selection bias. Kaplan-Meier curves and Cox risk regression models were used to analyse progression-free survival (PFS) and overall survival (OS).

Results

The optimal cut-off point for NAC cycles was 5. There were no significant differences in R0 resection, pathological response or postoperative complications between the groups with a low number of NAC cycles group (≤5 cycles, n=80) and high number of NAC cycles (>5 cycles, n=49). Patients with a high number of NAC cycles were more likely to have NAC toxicity than those with a low number of cycles (87.8% vs. 65.0%, P=0.004). Multivariate analysis revealed that >5 NAC cycles was an independent predictor of reduced PFS (HR =1.808, 95% CI: 1.205–2.712, P=0.004) and reduced OS (HR =1.723, 95% CI: 1.041–2.851, P=0.034). In the oxaliplatin-based regimen group, patients with a low number of NAC cycles had a better PFS (P<0.001, mPFS: 14.7 vs. 5.4 months) and better OS (P=0.018, mOS: 57.7 months vs. 41.0 months) than those with a high number of cycles. After 1:1 propensity matching (34 cases vs. 34 cases), multivariate analysis revealed that >5 NAC cycles was an independent predictor of reduced PFS (HR =2.265, 95% CI: 1.281–4.007, P=0.005) and reduced OS (HR =2.813, 95% CI: 1.359–5.822, P=0.005). In the oxaliplatin-based regimen group, patients with a low number of NAC cycles had better PFS (P<0.001, mPFS: 17.5 vs. 5.6 months) and better OS (P=0.008, mOS: 59.0 vs. 31.8 months) than those with a high number of cycles.

Conclusions

Fewer than 5 NAC cycles was optimal for biologically resectable CLOM patients. Giving more than 5 NAC cycles was unnecessary because a higher number of NAC cycles has more unfavourable survival and higher NAC toxicities, while leading to similar R0 resection rates and pathological responses.

Efficacy of cabazitaxel and the influence of clinical factors on the overall survival of patients with castration-resistant prostate cancer: A local experience of a multicenter retrospective study

AIM

To date, the optimal sequencing of life-prolonging therapies for patients with metastatic castration-resistant prostate cancer (mCRPC) remains unclear owing to a lack of prospective trials. This study aimed to evaluate the efficacy and safety of cabazitaxel (CBZ) treatment and examine the prognostic factors for oncological outcomes in patients with mCRPC who received CBZ after docetaxel (DOC).

METHODS

This multi-institutional retrospective study included 44 patients with mCRPC who received CBZ. All enrolled patients had histologically confirmed prostate cancer (PCa) with distant metastases and had received DOC before CBZ administration. The primary endpoint was the oncological outcomes, including the overall (OS) and progression-free survival (PFS). The secondary endpoints were adverse events due to CBZ and rates of ≥30% reduction in prostate-specific antigen (PSA) levels.

RESULTS

The median follow-up period was 9.2 months (range, 0.2-34 months). During this time, 34 patients (77%) died of PCa. The median OS and PFS were 12.2 (range, 0.2-34 months) and 1.4 months (range, 0.4-17 months), respectively. According to the PSA decline rate, patients who achieved a ≥30% reduction in PSA levels had significantly longer OS than those who showed a <30% reduction in PSA levels (P = 0.002). Regarding the number of cycles of CBZ, patients who received ≥4 cycles of CBZ showed significantly longer OS than those who received <4 cycles of CBZ (P < 0.001). Patients who had visceral metastasis showed significantly shorter OS than those without visceral metastasis (P = 0.012).

CONCLUSION

This study demonstrated that CBZ was effective and safe in Japanese local patients in a real-world setting. Patients with mCRPC who received ≥4 cycles of CBZ showed a ≥30% reduction in the serum PSA levels, and did not have visceral metastasis might achieve longer OS.

[The patterns of seasonal outbreaks of acute respiratory diseases]

The COVID-19 epidemic cause is considered to be "patient zero" contaminated by coronavirus infection in December 2019 in China. However, accumulated facts dispute this version of events. The first infected patient appeared in September in the United States, in December - in France. in November-December pneumonia of similar severity raged in Russia. It is difficult to explain numerous outbreaks of simultaneous contagions in isolated staffs, including military garrisons. In most of healthy adults' antibodies to coronavirus are found. The most of infected patients have no symptoms of disease. To explain these paradoxes ecological hypothesis is proposed - humanity and coronaviruses have been interacting evolutionarily for thousands years in system of biogeocenosis, periodically confronting under influence of cyclical ecological processes. The purpose of study is to investigate relationship between mortality of acute out-of-hospital pneumonia, coronavirus ones included, and cyclical fluctuations of environmental conditions. The primary material was obtained from data of Rosstat, international information bases, results of scientific studies. The classic methods of medical statistics were applied. The summer solstice (June) was used as reference point for estimating dynamics of monthly mortality in 2015-2020. The analysis of dynamics of mortality of pneumonia averaged for 2015-2020 revealed three epidemic waves with peaks in October, January, and March. Such cyclical pattern was consistently reproduced for particular years in 2015-2020. The first wave always was the lowest one. When the second wave exceeds the third one, increase in mortality in February and March was the smallest one. The greatest epidemic losses were established at the plateau. In 2020, the rate of coronavirus infection in the world coincides with the established cyclicity. The stable reproducibility of three peaks of mortality in same months testifies their regular character. The cause of all this may be the cyclicity of ecological interactions between coronaviruses and human population.

Effect of Alkaline Black Liquor Recycling on Alkali Combined with Ozone Pretreatment of Corn Stalk

In the early stage, the best conditions for alkali-bound ozone pretreatment were studied. But after treatment, the alkaline black liquor was directly discarded due to the large amount of organic matter, resulting in environmental pollution and waste of resources. In this paper, the alkaline black liquor was recycled under the optimal pretreatment conditions. The results showed that the number of alkaline black liquor cycles had little effect on hemicellulose content, and had a great influence on cellulose content and lignin content. Through structural characterization of corn stover, it was found that the pretreatment caused structural changes of lignin in straw. However, when the alkaline black liquor was recycled for the fourth time, the ether bond in the side chain of lignin and the covalent bond between the components were not sufficiently destroyed, and the damage to the phenolic hydroxyl group was also weakened. It was indicated that when the alkaline black liquor was recycled for the fourth time, the destruction effect of the alkaline black liquor on the straw was significantly inhibited. Therefore, the optimal circulation time of alkaline black liquor was three times, and the cellulolytic conversion rate was 81.53%.

A brief history of circannual time

Innate circannual timing is an ancestral trait that first evolved in free-living eukaryotic cells some 2000 million years ago, with marine algae of the genus Allexandrium providing a living unicellular model. This species shows the primitive trait of 'alternation of generations', where the organism alternates between fast replicating vegetative cells in the summer and a dormant cystic cell over the winter. The resistant cysts sink into the cold ocean sediments. Remarkably, excystment in spring is governed by an endogenous circannual timing mechanism. Thus, a tiny, short-lived unicell can utilise a circannual clock as part of the life-history programme of the species. Innate timing allows for major adjustments in physiology and behaviour in anticipation of the seasons, and provides an internalised sense of seasonal time for the many species where standard environmental cues are weak or ambiguous. This is a highly adaptive strategy irrespective of the size and longevity of an organism. Circannual rhythms are expressed by a diverse range of organisms, from flowering plants to mammals, interwoven into the life-history programme of each species, being a consequence of forever living in a periodic world. In complex vertebrates, the early division of the zygote potentially carries circannual timer genes into all progeny cells and tissues. This supports the concept of a 'clock-shop' where cell-autonomous long-term rhythms are generated in each tissue, orchestrated by a central circannual pacemaker system. This is analogous to the organisation of the circadian timing system. For the circannual time-scale, specialised thyrotroph cells located in the pars tuberalis of the pituitary gland and adjacent tanycyte cells located in the ependymal wall of the third cerebral ventricle of the brain act as putative central circannual pacemakers. At a molecular level, epigenetically regulated, cyclical remodelling of chromatin, which determines whether specific circannual timer genes are transcriptionally active, or not, is considered to drive the oscillation between the summer and winter phenotypes.

PREY ADAPTATION AS A CAUSE OF PREDATOR-PREY CYCLES

We analyze simple models of predator-prey systems in which there is adaptive change in a trait of the prey that determines the rate at which it is captured by searching predators. Two models of adaptive change are explored: (1) change within a single reproducing prey population that has genetic variation for vulnerability to capture by the predator; and (2) direct competition between two independently reproducing prey populations that differ in their vulnerability. When an individual predator's consumption increases at a decreasing rate with prey availability, prey adaptation via either of these mechanisms may produce sustained cycles in both species' population densities and in the prey's mean trait value. Sufficiently rapid adaptive change (e.g., behavioral adaptation or evolution of traits with a large additive genetic variance), or sufficiently low predator birth and death rates will produce sustained cycles or chaos, even when the predator-prey dynamics with fixed prey capture rates would have been stable. Adaptive dynamics can also stabilize a system that would exhibit limit cycles if traits were fixed at their equilibrium values. When evolution fails to stabilize inherently unstable population interactions, selection decreases the prey's escape ability, which further destabilizes population dynamics. When the predator has a linear functional response, evolution of prey vulnerability always promotes stability. The relevance of these results to observed predator-prey cycles is discussed.

Failure to reproduce period-dependent song cycles in Drosophila is due to poor automated pulse-detection and low-intensity courtship

Stern has criticized a body of work from several groups that have independently studied the so-called "Kyriacou and Hall" courtship song rhythms of male Drosophila melanogaster, claiming that these ultradian ∼60-s cycles in the interpulse interval (IPI) are statistical artifacts that are not modulated by mutations at the period (per) locus [Stern DL (2014) BMC Biol 12:38]. We have scrutinized Stern's raw data and observe that his automated song pulse-detection method identifies only ∼50% of the IPIs found by manual (visual and acoustic) monitoring. This critical error is further compounded by Stern's use of recordings with very little song, the large majority of which do not meet the minimal song intensity criteria which Kyriacou and Hall used in their studies. Consequently most of Stern's recordings only contribute noise to the analyses. Of the data presented by Stern, only per^L and a small fraction of wild-type males sing vigorously, so we limited our reanalyses to these genotypes. We manually reexamined Stern's raw song recordings and analyzed IPI rhythms using several independent time-series analyses. We observe that per^L songs show significantly longer song periods than wild-type songs, with values for both genotypes close to those found in previous studies. These per-dependent differences disappear when the song data are randomized. We conclude that Stern's negative findings are artifacts of his inadequate pulse-detection methodology coupled to his use of low-intensity courtship song records.

Synthetic Strategies for Peroxide Ring Construction in Artemisinin

The present review summarizes publications on the artemisinin peroxide fragment synthesis from 1983 to 2016. The data are classified according to the structures of a precursor used in the key peroxidation step of artemisinin peroxide cycle synthesis. The first part of the review comprises the construction of artemisinin peroxide fragment in total syntheses, in which peroxide artemisinin ring resulted from reactions of unsaturated keto derivatives with singlet oxygen or ozone. In the second part, the methods of artemisinin synthesis based on transformations of dihydroartemisinic acid are highlighted.

The Potential Benefit of Three vs. Six Cycles of Carboplatin, Etoposide, and Vincristine in Postenucleation High-Risk Patients with IRSS Stage I Retinoblastoma

PURPOSE

To compare the clinical effects of different cycles of carboplatin, etoposide, and vincristine (CEV) regimens of adjuvant chemotherapy in postenucleation high-risk patients with IRSS Stage I retinoblastoma (RB).

METHODS

A retrospective analysis of 53 RB patients hospitalized in the Zhongshan Ophthalmic Center of Sun Yat-sen University was performed. All patients had unilateral involvement, received enucleation treatment, were diagnosed as RB by pathology, and had high-risk pathological factors. Patients either refused postoperative chemotherapy or received three or six cycles of CEV regimen chemotherapy. The clinical information, treatment, and results of patients in all groups were compared.

RESULTS

A total of 19 cases refused postenucleation chemotherapy, 18 cases received three cycles, and 16 cases received six cycles of the CEV regimen chemotherapy. The 5-year disease-free survival rate and the overall survival (OS) rate in the chemotherapy group were higher than those in the non-chemotherapy group (97.1% vs. 63.2%, p = 0.001) and were not different between the three-cycle chemotherapy group and the six-cycle chemotherapy group (94.4% vs. 100%, p = 0.35).

CONCLUSION

After eye enucleation for patients with high-risk unilateral RB, the CEV regimen chemotherapy was associated with a higher survival rate. The three-cycle CEV regimen adjuvant chemotherapy was effective and is expected to replace the six-cycle CEV regimen chemotherapy.

A genotype network reveals homoplastic cycles of convergent evolution in influenza A (H3N2) haemagglutinin

Networks of evolving genotypes can be constructed from the worldwide time-resolved genotyping of pathogens like influenza viruses. Such genotype networks are graphs where neighbouring vertices (viral strains) differ in a single nucleotide or amino acid. A rich trove of network analysis methods can help understand the evolutionary dynamics reflected in the structure of these networks. Here, I analyse a genotype network comprising hundreds of influenza A (H3N2) haemagglutinin genes. The network is rife with cycles that reflect non-random parallel or convergent (homoplastic) evolution. These cycles also show patterns of sequence change characteristic for strong and local evolutionary constraints, positive selection and mutation-limited evolution. Such cycles would not be visible on a phylogenetic tree, illustrating that genotype network analysis can complement phylogenetic analyses. The network also shows a distinct modular or community structure that reflects temporal more than spatial proximity of viral strains, where lowly connected bridge strains connect different modules. These and other organizational patterns illustrate that genotype networks can help us study evolution in action at an unprecedented level of resolution.

The effect of oral-like environment on dental implants' fatigue performance

AIM AND OBJECTIVES

The aim of this study was to evaluate the influence of fluid environment mimicking intra-oral conditions on fatigue performance of standard diameter, 3.75-mm implants. Dental implants placed intra-orally are repeatedly submitted to mastication loads in the oral environment, which differ substantially from room-air standard laboratory conditions. Several studies that examined fracture surfaces of intra-orally fractured dental implants have identified corrosion fatigue as the main failure mechanism. Yet, fatigue performance of dental implants has been essentially studied in room air, based on the premise that the implant material is relatively resistant to corrosion in the intra-oral environment.

MATERIAL AND METHODS

Thirty-two 3.75-mm titanium alloy implants were tested under cyclic compressive loading. The tests were performed in artificial saliva substitute containing 250 ppm of fluoride. The loading machine stopped running when the implant structure collapsed or when it completed 5 × 10(6) cycles without apparent failure. The load vs. number of cycles was plotted as curve for biomechanical fatigue analysis (S-N curve). The S-N curve plotted for the artificial saliva test was compared to the curve obtained previously for the same implants tested in a room-air environment. Failure analysis was performed using scanning electron microscopy (SEM).

RESULTS

A comparison of the S-N curves obtained in artificial saliva and in room air showed a considerable difference. The S-N curve obtained in the artificial saliva environment showed a finite life region between 535N and 800N. The transition region was found below 465N, with a probability of survival of 50%, while in room air, the transition region was between 810N and 620N and an infinite life region below 620N was identified.

CONCLUSIONS

The results of this study show that environmental conditions adversely affect implants' fatigue performance. This fact should be taken into account when evaluating the mechanical properties of dental implants.

Building blocks of self-sustained activity in a simple deterministic model of excitable neural networks

Understanding the interplay of topology and dynamics of excitable neural networks is one of the major challenges in computational neuroscience. Here we employ a simple deterministic excitable model to explore how network-wide activation patterns are shaped by network architecture. Our observables are co-activation patterns, together with the average activity of the network and the periodicities in the excitation density. Our main results are: (1) the dependence of the correlation between the adjacency matrix and the instantaneous (zero time delay) co-activation matrix on global network features (clustering, modularity, scale-free degree distribution), (2) a correlation between the average activity and the amount of small cycles in the graph, and (3) a microscopic understanding of the contributions by 3-node and 4-node cycles to sustained activity.

Effect of dental implant diameter on fatigue performance. Part I: mechanical behavior

AIM

The purpose of this study was to evaluate the effect of the implants' diameter on the mechanical function and load-fatigue performance of dental implants.

MATERIALS AND METHODS

Three groups of implants with different diameters (3.3 mm, 3.75 mm and 5 mm), were tested under static and cyclic compressive loading. A total number of 15 implants for the static test and 112 implants for the cyclic-fatigue test. In the cyclic test, the machine ceased operating when the structure collapsed or when it reached 5 × 10(6) cycles without apparent failure. The load versus the number of cycles was plotted as curves for biomechanical analysis (S-N curve) for each implant diameter.

RESULTS

The S-N curve plotted for the 5 mm implants showed classic fatigue behavior with a finite life region starting from 620N. The same was observed for the 3.75 mm diameter implants, with a finite life region starting below 620N. By contrast, the 3.3 mm diameter implants failed to show predictable fatigue behavior and a fatigue limit could not be defined.

CONCLUSIONS

The results of this study emphasize the importance of implant diameter on fatigue behavior. Narrow implants failed to show typical fatigue behavior which might be attributed to the implant design.

A Reevaluation of Density-Dependent Population Cycles in Open Systems

Studies motivated by consideration of barnacle populations have led to the prediction of two different dynamic states for space-limited open populations subject to density-dependent mortality. Population densities may cycle or fluctuate stochastically around a mean value. Despite the potential generality of the associated theory, there are few examples of population cycling in open systems that have been shown to be driven by density-dependent effects. This may be because settlement and growth processes are generally too slow or too variable to generate consistent cycles. An alternative explanation is examined in this article using spatially explicit simulations. Even under conditions of consistent settlement and growth, the cycles predicted in at least one previous study are shown to represent a special case. Clear population cycles are only observed when the density-dependent disturbances are constrained to reoccur in exactly the same location. In the more general case, where density-dependent disturbances respond to local variations in population density, the cycling predicted from simple models is difficult to detect. Hence, a failure to detect cycling in population density does not refute a role for density dependence. Density-dependent disturbances can create a characteristic spatial structure consisting of a mosaic of cohorts.