Flexible dielectric waveguides with powder cores

Flexible dielectric waveguides have been demonstrated at 10 GHz and 94 GHz using thin-wall polymer tubing filled with low-loss, high-dielectric-constant powders. Absorptive losses of the order of 10 dB/m were measured at 94 GHz. with nickel-aluminium titanate and barium tetratitanate powder in polytetrafluoroethylene (PTFE) lightweight electrical tubing. Bending losses at 94 GHz were negligible for curvature radii greater than 4 cm. M.H. Kuhn's (1974) theory of three-region cylindrical dielectric waveguide was used to calculate dispersion curves for the lower-order modes for several combinations of dimensions and dielectric constants. Good agreement was obtained between experimental and theoretical values of guide wavelength. A scheme is proposed for classifying hybrid modes of three-region guides based on the ratio |Ez/Hz|. For two-region guides, this reduces to E. Snitzer's (1961) familiar scheme

Powder Core Dielectric Waveguides

A powder-filled surface of a led groove in the teflon substrate has been demonstrated as a dielectric waveguide at 94 GHz. Guide wavelengths measured for combinations of guide dimensions and powders agree within 10% of values predicted by Marcatili 's approximate theory. Attenuation constants of 0.2 to 0.3 dB/cm were measured for barium tetra-titanate

Modular deconstruction reveals the dynamical and physical building blocks of a locomotion motor program

The neural substrates of motor programs are only well understood for small, dedicated circuits. Here we investigate how a motor program is constructed within a large network. We imaged populations of neurons in the Aplysia pedal ganglion during execution of a locomotion motor program. We found that the program was built from a very small number of dynamical building blocks, including both neural ensembles and low-dimensional rotational dynamics. These map onto physically discrete regions of the ganglion, so that the motor program has a corresponding modular organization in both dynamical and physical space. Using this dynamic map, we identify the population potentially implementing the rhythmic pattern generator and find that its activity physically traces a looped trajectory, recapitulating its low-dimensional rotational dynamics. Our results suggest that, even in simple invertebrates, neural motor programs are implemented by large, distributed networks containing multiple dynamical systems

Exonuclease activity and P nucleotide addition in the generation of the expressed immunoglobulin repertoire

BACKGROUND: Immunoglobulin rearrangement involves random and imprecise processes that act to both create and constrain diversity. Two such processes are the loss of nucleotides through the action of unknown exonuclease(s) and the addition of P nucleotides. The study of such processes has been compromised by difficulties in reliably aligning immunoglobulin genes and in the partitioning of nucleotides between segment ends, and between N and P nucleotides. RESULTS: A dataset of 294 human IgM sequences was created and partitioned with the aid of a probabilistic model. Non-random removal of nucleotides is seen between the three IGH gene types with the IGHV gene averaging removals of 1.2 nucleotides compared to 4.7 for the other gene ends (p < 0.001). Individual IGHV, IGHD and IGHJ gene subgroups also display statistical differences in the level of nucleotide loss. For example, within the IGHJ group, IGHJ3 has average removals of 1.3 nucleotides compared to 6.4 nucleotides for IGHJ6 genes (p < 0.002). Analysis of putative P nucleotides within the IgM and pooled datasets revealed only a single putative P nucleotide motif (GTT at the 3' D-REGION end) to occur at a frequency significantly higher then would be expected from random N nucleotide addition. CONCLUSIONS: The loss of nucleotides due to the action of exonucleases is not random, but is influenced by the nucleotide composition of the genes. P nucleotides do not make a significant contribution to diversity of immunoglobulin sequences. Although palindromic sequences are present in 10% of immunologlobulin rearrangements, most of the 'palindromic' nucleotides are likely to have been inserted into the junction during the process of N nucleotide addition. P nucleotides can only be stated with confidence to contribute to diversity of less than 1% of sequences. Any attempt to identify P nucleotides in immunoglobulins is therefore likely to introduce errors into the partitioning of such sequences

Exploring the role of the patient–physician relationship on insulin adherence and clinical outcomes in type 2 diabetes: Insights from the MOSAIc study

BackgroundThe 2‐year prospective MOSAIc (Multinational Observational Study assessing Insulin use: understanding the challenges associated with progression of therapy) study is investigating whether patient‐, physician‐, and health system‐related factors affect outcomes in patients with type 2 diabetes (T2D). This baseline subanalysis investigated how aspects of the patient–physician relationship are associated with diabetes‐related distress, insulin adherence, and glycemic control.MethodsPatients with T2D taking insulin for ≥3 months were recruited at primary care and specialty practice sites in 18 countries. Physicians provided usual care. Clinical history and most recent HbA1c values were collected; patients were surveyed regarding their perception of physician interactions, diabetes‐related distress level, and insulin adherence.ResultsThe analysis population comprised 4341 patients. Four (of six) domains showed a significant relationship with total diabetes‐related distress (P < 0.01). Poor insulin adherence was associated with greater diabetes‐related distress (adjusted odds ratio [aOR] 1.14; 95% confidence interval [CI] 1.06–1.22), higher Discrimination (aOR 1.13; 95% CI 1.02–1.27) and Hurried Communication (aOR 1.35; 95% CI 1.20–1.53) scores, and a lower Explained Results score (aOR 0.86; 95% CI 0.77–0.97). Poor insulin adherence was associated with a 0.43% increase in HbA1c, whereas a 1‐unit increase in total diabetes‐related distress and Hurried Communication scores was associated with a 0.171% and 0.145% increase in HbA1c, respectively.ConclusionsPatients distressed about living with T2D, and dissatisfied with aspects of their interactions with physicians, exhibited poor insulin adherence. Perceived physician inattention and lack of engagement (and diabetes‐related distress) directly affect insulin adherence and glycemic control.背景为期2年的前瞻性MOSAIc(Multinational Observational Study assessing Insulin use: understanding the challenges associated with progression of therapy,评估胰岛素使用情况的多国观察性研究:了解治疗进展带来的挑战)研究调查了患者‐、医生‐、医疗卫生系统‐相关因素是否会对2型糖尿病患者的临床结局产生影响。这项基线亚组分析调查了患者‐医生关系对糖尿病相关的不适、胰岛素依从性以及血糖控制可造成何种影响。方法在18个国家的初级保健以及专业医疗机构中招募胰岛素使用时间≥ 3个月的2型糖尿病患者。医生提供了常规的医疗护理。收集临床病史以及最近的HbA1c值;调查患者对医患之间关系的看法、与糖尿病相关的不适程度以及胰岛素依从性。结果分析人群包含了4341名患者。(在6个领域中)有4个方面与总的糖尿病相关不适之间具有显著的相关性(P < 0.01)。胰岛素依从性差与较高的糖尿病相关不适(校正过的优势比[aOR]为1.14;95%置信区间[CI]为1.06‐1.22)、较高的歧视(aOR为1.13;95% CI为1.02‐1.27)和仓促沟通(aOR为1.35;95% CI为1.20‐1.53)得分以及更低的解释病情得分(aOR为0.86;95% CI为0.77‐0.97)相关。胰岛素依从性差可导致HbA1c升高0.43%,然而总的糖尿病相关不适以及仓促沟通得分每增加1个单位就可以导致HbA1c分别升高0.171%与0.145%。结论患者感到苦恼的是2型糖尿病影响到了他们的生活,对于与医生的交流感到不够满意,而且表现为胰岛素依从性差。患者觉得医生不关心自己、缺乏交流(以及糖尿病本身造成的相关痛苦)会直接影响到胰岛素依从性以及血糖控制。HighlightsPatient perceptions of the quality of their interactions with their physicians have a significant association with total diabetes‐related distress. Diabetes‐related distress and patient–physician interactions have a significant independent association with insulin adherence and HbA1c level.This study delineates specific aspects of the patient–physician interaction that are linked to diabetes‐related distress, insulin adherence behavior, and glycemic control.Path analysis showing associations between patient–physician interactions, diabetes‐related distress, insulin adherence, and HbA1c level. The model is not adjusted for baseline covariates and shows only those factors with at least one significant interaction. Parameter coefficients in the path analysis are shown.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137500/1/jdb12443.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137500/2/jdb12443_am.pd

Can Life develop in the expanded habitable zones around Red Giant Stars?

We present some new ideas about the possibility of life developing around sub-giant and red giant stars. Our study concerns the temporal evolution of the habitable zone. The distance between the star and the habitable zone, as well as its width, increases with time as a consequence of stellar evolution. The habitable zone moves outward after the star leaves the main sequence, sweeping a wider range of distances from the star until the star reaches the tip of the asymptotic giant branch. If life could form and evolve over time intervals from $5 \times 10^8$ to $10^9$ years, then there could be habitable planets with life around red giant stars. For a 1 M$_{\odot}$ star at the first stages of its post main-sequence evolution, the temporal transit of the habitable zone is estimated to be of several 10$^9$ years at 2 AU and around 10$^8$ years at 9 AU. Under these circumstances life could develop at distances in the range 2-9 AU in the environment of sub-giant or giant stars and in the far distant future in the environment of our own Solar System. After a star completes its first ascent along the Red Giant Branch and the He flash takes place, there is an additional stable period of quiescent He core burning during which there is another opportunity for life to develop. For a 1 M$_{\odot}$ star there is an additional $10^9$ years with a stable habitable zone in the region from 7 to 22 AU. Space astronomy missions, such as proposed for the Terrestrial Planet Finder (TPF) and Darwin should also consider the environments of sub-giants and red giant stars as potentially interesting sites for understanding the development of life