Is It Always Unethical to Use a Placebo in a Clinical Trial?

Background to the debate: Placebos are used in trials to conceal whether a treatment is being given or not and hence to control for the psychosomatic effects of offering treatment. Placebo-controlled trials are controversial. Critics of such trials argue that if a proven effective therapy exists, a placebo should not be used. But proponents argue that placebo trials are still crucial to prove the efficacy and safety of many treatments.     

Genetic Characterization of a Core Set of a Tropical Maize Race Tuxpe?o for Further Use in Maize Improvement

The tropical maize race Tuxpeño is a well-known race of Mexican dent germplasm which has greatly contributed to the development of tropical and subtropical maize gene pools. In order to investigate how it could be exploited in future maize improvement, a panel of maize germplasm accessions was assembled and characterized using genome-wide Single Nucleotide Polymorphism (SNP) markers. This panel included 321 core accessions of Tuxpeño race from the International Maize and Wheat Improvement Center (CIMMYT) germplasm bank collection, 94 CIMMYT maize lines (CMLs) and 54 U.S. Germplasm Enhancement of Maize (GEM) lines. The panel also included other diverse sources of reference germplasm: 14 U.S. maize landrace accessions, 4 temperate inbred lines from the U.S. and China, and 11 CIMMYT populations (a total of 498 entries with 795 plants). Clustering analyses (CA) based on Modified Rogers Distance (MRD) clearly partitioned all 498 entries into their corresponding groups. No sub clusters were observed within the Tuxpeño core set. Various breeding strategies for using the Tuxpeño core set, based on grouping of the studied germplasm and genetic distance among them, were discussed. In order to facilitate sampling diversity within the Tuxpeño core, a minicore subset of 64 Tuxpeño accessions (20% of its usual size) representing the diversity of the core set was developed, using an approach combining phenotypic and molecular data. Untapped diversity represents further use of the Tuxpeño landrace for maize improvement through the core and/or minicore subset available to the maize community.     

Is It Ethical to Use Enhancement Technologies to Make Us Better than Well?

BACKGROUND TO THE DEBATE: A variety of biomedical technologies are being developed that can be used for purposes other than treating disease. Such "enhancement technologies" can be used to improve our appearance and regulate our emotions, with the goal of feeling "better than well." While these technologies can help people adapt to their rapidly changing lifestyles, their use raises important ethical issues.     

Is T-Wave Alternans Testing Feasible in Candidates for Prophylactic Implantable Defibrillators?

Aims

Previous studies have demonstrated that microvolt T-wave alternans (TWA) screening in patients with ischaemic and dilated cardiomyopathy is effective in identifying patients at high or low risk of sudden cardiac death. It remains unclear which percentage of potential recipients of an implantable cardioverter defibrillator (ICD) are able to perform TWA testing using an exercise protocol which is, at this moment, the golden standard. In this study, we evaluated the feasibility of TWA in the risk stratification of potential ICD recipients with ischaemic or dilated cardiomyopathy.

Methods and Results

Medical charts of 165 primary prevention ICD recipients were reviewed to decide if patients were able to perform a TWA exercise test or not. Reasons to waiver a test were: atrial fibrillation or flutter, pacemaker dependency, recent (cardiovascular) surgery (<1 month) and inability to exercise. Of the potential ICD recipients 35% had one or more of these contraindications and were therefore not suitable for testing.

Conclusion

In several studies, TWA is a promising risk stratifier for predicting sudden cardiac death; however, in our population, 35% of the potential ICD candidates could not be tested. In order to fulfil its promise as a predictor for SCD, an alternative means to measure TWA needs to be evaluated.     

What Justifies a Future with Humans in It?

Antinatalist commentators recommend that humanity bring itself to a close, on the theory that pain and suffering override the value of any possible life. Other commentators do not require the voluntary extinction of human beings, but they defend that outcome if people were to choose against having children. Against such views, Richard Kraut has defended a general moral obligation to people the future with human beings until the workings of the universe render such efforts impossible. Kraut advances this view on the grounds that we are obliged to exercise beneficence toward others and on the grounds that the goods available in human lives are morally compelling. This account ultimately succeeds in making no more than a prima facie defense of human perpetuation because considerations of beneficence could override – in some cases probably should – override any duty to perpetuate human beings. While the goods of human life may be distinctive, they cannot serve as reason‐giving in regard to their own perpetuation. Ironically, the exercise of beneficence may authorize the extinction of human beings, if it becomes possible to enhance the goods available to human descendants in a way that moves them away from human nature as now given. The defense of a morally obligatory and strictly human future remains elusive, even as it becomes morally desirable to work against Fateful Catastrophes, those human‐caused events that threaten to extinguish existing lives already good and enriching for their bearers.     

ORTHOVOLTAGE THERAPY—Is There Still a Need for It?

Since there has been no significant increase in cancer cure rates in recent years that can be attributed to the treatment method alone, new and more radical procedures have been introduced in an effort to improve the results. In radiation therapy this has taken the form of supervoltage generators and in the use of high energy sources of radiation such as Cobalt 60 and Cesium 137. As this trend gains momentum, the place and future of orthovoltage therapeutic radiation (250 to 400 kilovolts) must be considered. General agreement is that supervoltage radiation offers an increase in depth dose and fewer local and systemic reactions, but it is too early to assess any change in cure rate. Measured against this is the danger of deep tissue damage, less relative biological efficiency and increased costs.In view of our ignorance regarding cancer, abandoning proved procedures prematurely is unjustified. The most promising trend lies in improved training and in the skillful use of what we have. While it may be that radiation of higher voltages will improve the morbidity and mortality rates, it would be better to concentrate these new modalities in centers where large numbers of cases are available.     

State Transition,Is It a Photochemical or Non-photochemical Process in Leaf in Response to Irradiance?

The response of steady-state fluorescence (Fs) to irradiance in apple (Malus pumila Mill. cv. Tengmu No.1/Malus hupehensis Rehd.) leaf increased and decreased at light levels below and above 400 mmol.m-2.s-1 photosynthetic photon flux density (PPFD), respectively, while the light-adapted maximal fluorescence (Fm') and minimal fluorescence (Fo') decreased constantly with the increasing PPFD, and the closure of photosystem Ⅱ reaction center (PSⅡ RC) increased continuously, reflected by the chlorophyll fluorescence parameter of (Fs-Fo')/(Fm'-Fo'). These facts indicated that decrease of Fs above 400 mmol.m-2.s-1 PPFD was not caused by closure of PSⅡ RC, but was mainly resulted from the process of light transfer from light-harvesting complexⅡ (LHCⅡ) to PSⅡ RC. In the presence of N-ethylmaleimide (NEM), an inhibitor of photosynthetic state transition, Fs kept on increasing in apple leaf at light levels from 400 to 700 mmol.m-2.s-1, which was the photosynthetic saturation irradiance of apple leaves. In addition, Fs still increased at light levels over 700 mmol.m-2.s-1 in apple leaf pre-treated with dithiothreitol (DTT), an inhibitor of xanthophyll cycle. These changes showed that state transition and xanthophyll cycle caused a decrease of Fs in apple leaf at light levels below and above the photosynthetic saturation irradiance, respectively. When apple leaf was pre-treated with NEM, the PSⅡ apparent rate of photochemical reaction (P-rate) and photochemical quenching (qP) decreased significantly in the light range of 600-800 mmol.m-2.s-1, but the non-photochemical quenching (qN) existed a small increase at 600-800 mmol.m-2.s-1 and a decrease above 800 mmol.m-2.s-1. These phenomena suggested that state transition was mainly a photochemical and a non-photochemical process in apple leaf responding to light lower and higher than photosynthetic saturation irradiance, respectively.     

Dealing with Lead in Hybrid Perovskite: A Challenge to Tackle for a Bright Future of This Technology?

Hybrid Perovskite (HP) semiconductors have been skyrocketing the field of new generation photovoltaics and expanding into advanced optoelectronics. Perovskite photovoltaics (PV) can give a tremendous push to the green energy transition, which calls for efficient, low cost, but also environmentally friendly solutions. Halide perovskites present a serious drawback related to the presence of toxic materials, i.e., lead, with its associated health and environment concerns. These concerns severely hamper their commercialization. So far, only a few viable alternatives to Pb have been found, which lag behind in terms of power conversion efficiency. Here, a forward‐looking perspective is developed presenting different potential strategies to overcome the environmental and health issues related to the use and release of lead for operative HP solar cells. The possible lead‐leakage paths and related “remediation” tools are reviewed, and possible strategies are collated with a view to beginning a new era of lead containing HP devices. Finally, through a comparison with existing lead‐based technology, a comparative study is presented to provide the tools that are essential for a real evaluation of the impact of lead content on HP commercialization.     

Is It Possible to Manipulate Scelionidae Wasps’ Preference to a Target Host?

Parasitoid host selection is mainly mediated by chemical cues, which can be adjusted by experience, changing their innate behavior. Therefore, this study evaluated if immature experience (pre-imaginal conditioning) on eggs and volatiles from different host eggs has influence on parasitism and chemotaxic behavior of Telenomus podisi Ashmead and/or Trissolcus basalis Wollaston (Hymenoptera: Scelionidae). Both wasp species were submitted to a multiple-choice parasitism test among Euschistus heros (Fabricius), Piezodorus guildinii (Westwood), and Nezara viridula L. (Hemiptera: Pentatomidae) (Hemiptera: Pentatomidae) egg masses. Eggs from these three stink bugs were equally offered to female parasitoids. After that, adults which emerged from each host were also exposed to parasitism in a multiple-choice test for up to an additional generation. Moreover, in olfactometer “Y,” the behavior of innate and experienced T. podisi females to volatiles from hosts’ egg extracts was tested, to study their learning and memory ability. The original host had influence on T. podisi parasitism; however, T. basalis always parasitized more N. viridula eggs independently of its last rearing host. Innate T. podisi females responded positively to E. heros and P. guildinii egg volatiles, but this behavior was not observed in N. viridula. When T. podisi females were experienced on egg volatiles from a new host, they showed significant learning and memory ability for the specific host volatile for, at least, 24 h. Experienced wasps responded positively to N. viridula and through this result we have evidences about the possibility to manipulate wasp’s preferences to a specific target host.     

Dynamic Scapular Movement Analysis: Is It Feasible and Reliable in Stroke Patients during Arm Elevation?

Knowledge of three-dimensional scapular movements is essential to understand post-stroke shoulder pain. The goal of the present work is to determine the feasibility and the within and between session reliability of a movement protocol for three-dimensional scapular movement analysis in stroke patients with mild to moderate impairment, using an optoelectronic measurement system. Scapular kinematics of 10 stroke patients and 10 healthy controls was recorded on two occasions during active anteflexion and abduction from 0° to 60° and from 0° to 120°. All tasks were executed unilaterally and bilaterally. The protocol’s feasibility was first assessed, followed by within and between session reliability of scapular total range of motion (ROM), joint angles at start position and of angular waveforms. Additionally, measurement errors were calculated for all parameters. Results indicated that the protocol was generally feasible for this group of patients and assessors. Within session reliability was very good for all tasks. Between sessions, scapular angles at start position were measured reliably for most tasks, while scapular ROM was more reliable during the 120° tasks. In general, scapular angles showed higher reliability during anteflexion compared to abduction, especially for protraction. Scapular lateral rotations resulted in smallest measurement errors. This study indicates that scapular kinematics can be measured reliably and with precision within one measurement session. In case of multiple test sessions, further methodological optimization is required for this protocol to be suitable for clinical decision-making and evaluation of treatment efficacy.     

Floral Temperature and Optimal Foraging: Is Heat a Feasible Floral Reward for Pollinators?

As well as nutritional rewards, some plants also reward ectothermic pollinators with warmth. Bumble bees have some control over their temperature, but have been shown to forage at warmer flowers when given a choice, suggesting that there is some advantage to them of foraging at warm flowers (such as reducing the energy required to raise their body to flight temperature before leaving the flower). We describe a model that considers how a heat reward affects the foraging behaviour in a thermogenic central-place forager (such as a bumble bee). We show that although the pollinator should spend a longer time on individual flowers if they are warm, the increase in total visit time is likely to be small. The pollinator's net rate of energy gain will be increased by landing on warmer flowers. Therefore, if a plant provides a heat reward, it could reduce the amount of nectar it produces, whilst still providing its pollinator with the same net rate of gain. We suggest how heat rewards may link with plant life history strategies.     

Is There a Lag Globally in Overweight Trends for Children Compared with Adults?

Objective: To determine relative trends in prevalence for overweight for adults compared with children across high‐income countries (Australia, United Kingdom, and United States), middle‐income countries (Brazil and Russia), and low‐income countries (China and Indonesia). Research Methods and Procedures: Extant nationally representative survey data from 1971 to the present are used. Prevalence of overweight for adults ≥18.0 years of age and children 6.0 to 17.9 years of age were used. Absolute and relative annual rates of change in prevalence of overweight in children and adults were the key outcomes. Results: Absolute rates of increase in overweight were higher among adults than among children in all studied countries except Australia. However, relative rates of increase in overweight indicate faster increases in overweight among children in Brazil, China, and the three high‐income countries. As a result, the relative excess of overweight among adults, seen initially in all countries, increased in Indonesia and Russia, but it decreased in Australia, Brazil, China, United Kingdom, and United States. In Brazil, time trends indicate an acceleration in the annual rate of change in overweight for children and a deceleration for adults, whereas in the United States, the increase in overweight shows acceleration for both children and adults. Discussion: In absolute terms, overweight increased faster among children than adults only in Australia; however, the relative gap between children and adults is closing in four additional countries, Brazil, China, the United Kingdom, and the United States.     

Routine HIV Testing among Hospitalized Patients in Argentina. Is It Time for a Policy Change?

Introduction

The Argentinean AIDS Program estimates that 110,000 persons are living with HIV/AIDS in Argentina. Of those, approximately 40% are unaware of their status, and 30% are diagnosed in advanced stages of immunosuppression. Though studies show that universal HIV screening is cost-effective in settings with HIV prevalence greater than 0.1%, in Argentina, with the exception of antenatal care, HIV testing is always client-initiated.

Objective

We performed a pilot study to assess the acceptability of a universal HIV screening program among inpatients of an urban public hospital in Buenos Aires.

Methods

Over a six-month period, all eligible adult patients admitted to the internal medicine ward were offered HIV testing. Demographics, uptake rates, reasons for refusal and new HIV diagnoses were analyzed.

Results

Of the 350 admissions during this period, 249 were eligible and subsequently enrolled. The enrolled population was relatively old compared to the general population, was balanced on gender, and did not report traditional high risk factors for HIV infection. Only 88 (39%) reported prior HIV testing. One hundred and ninety (76%) patients accepted HIV testing. In multivariable analysis only younger age (OR 1.02; 95%CI 1.003-1.05) was independently associated with test uptake. Three new HIV diagnoses were made (undiagnosed HIV prevalence: 1.58%); none belonged to a most-at-risk population.

Conclusions

Our findings suggest that universal HIV screening in this setting is acceptable and potentially effective in identifying undiagnosed HIV-infected individuals. If confirmed in a larger study, our findings may inform changes in the Argentinean HIV testing policy.     

Breast Contrast-Enhanced Ultrasound: Is a Scoring System Feasible? ----A Preliminary Study in China

Objectives

Although many studies about breast contrast-enhanced ultrasound had been conducted, clear diagnostic criteria for evaluating enhancement patterns are still lacking. This study aims to identify significant indicators for breast contrast-enhanced ultrasound and to establish an initial scoring system.

Materials and Methods

Totally 839 patients were included in the study. This study was divided into two parts. 364 patients were included in part 1 while 475 in part 2. Conventional ultrasound and contrast-enhanced ultrasound were used to examine each lesion. Only the cases in part 2 were also examined by elastography. In part 1, Logistic regression analysis was performed to predict significant variables. A 5-point scoring system was developed based on the results. In part 2, the scoring system was used to evaluate all the breast lesions. To evaluate the diagnostic efficacy of the new scoring system, it was compared with the system established for elastography and conventional ultrasound (BI-RADS).

Results

Three independent variables, namely, lesion scope, margin, and shape were selected in the final step of the logistic regression analysis in part 1. In part 2, the area under the ROC (receiver operating characteristic) curve for the contrast-enhanced scoring system was 0.912. The difference in the diagnostic capabilities of the contrast-enhanced scoring system and elastography was not statistically significant (P = 0.17). The difference in the diagnostic capabilities of the contrast-enhanced scoring system and BI-RADS was statistically significant (P<0.001).

Conclusions

The contrast-enhanced patterns of benign and malignant breast tumors are different. The application of a 5-point scoring system for contrast-enhanced ultrasound is clinically promising.     

Strong Emergence in Biological Systems: Is It Open to Mathematical Reasoning?

Acta Biotheoretica - Complex, multigenic biological traits are shaped by the emergent interaction of proteins being the main functional units at the molecular scale. Based on a phenomenological...     

Is there a role for actin in virus budding?

Electrophoretic data from both sodium dodecyl sulfate-polyacrylamide gels (SDS-PAGE) and acid-urea gels reveal a protein in purified murine mammary tumor virus (MuMTV) which co-migrates with purified chick skeletal muscle actin. 125I-labeling of intact and disrupted virus preparations shows that the actin-like protein is not artifactually adsorbed to the outside of virions during isolation. Quantitative SDS- PAGE and examination of negatively stained preparations show that the actin cannot be accounted for by a contaminating population of virus- free vesicles. The ultrastructure of mammary epithelial cells and of Rous sarcoma virus-transformed chick embryo fibroblasts shows that virus extrusion is associated with filament-containing cellular processes. In particular, MuMTV is released from the ends of long microvilli which contain a bundle of 6-8-nm microfilaments and share other structural features with intestinal microvilli. We suggest that virus nucleoids require an interaction with host cell contractile proteins for their extrusion from the cell.