The effects of solar radiation pressure on the motion of an artificial satellite

This thesis documents an investigation of the effect of solar radiation pressure on the motion of an artificial satellite. Consideration is given to the methods required for the inclusion of the discontinuous effect of the Earth's shadow. The analysis resulting from the description of a deformed diffusely reflecting balloon satellite and an algorithm describing the effects of Earth reflected solar radiation pressure are developed, culminating in the application of the derived theory to the orbital data of the balloon satellite, Explorer 19.

Primary and secondary somatosensory cortex responses to anticipation and pain: a magnetoencephalography study

Several brain regions, including the primary and secondary somatosensory cortices (SI and SII, respectively), are functionally active during the pain experience. Both of these regions are thought to be involved in the sensory-discriminative processing of pain and recent evidence suggests that SI in particular may also be involved in more affective processing. In this study we used MEG to investigate the hypothesis that frequency-specific oscillatory activity may be differentially associated with the sensory and affective components of pain. In eight healthy participants (four male), MEG was recorded during a visceral pain experiment comprising baseline, anticipation, pain and post-pain phases. Pain was delivered via intraluminal oesophageal balloon distension (four stimuli at 1 Hz). Significant bilateral but asymmetrical changes in neural activity occurred in the beta-band within SI and SII. In SI, a continuous increase in neural activity occurred during the anticipation phase (20-30 Hz), which continued during the pain phase but at a lower frequency (10-15 Hz). In SII, oscillatory changes only occurred during the pain phase, predominantly in the 20-30 Hz beta band, and were coincident with the stimulus. These data provide novel evidence of functional diversity within SI, indicating a role in attentional and sensory aspects of pain processing. In SII, oscillatory changes were predominantly stimulus-related, indicating a role in encoding the characteristics of the stimulus. We therefore provide objective evidence of functional heterogeneity within SI and functional segregation between SI and SII, and suggest that the temporal and frequency dynamics within cortical regions may offer valuable insights into pain processing.

The effect of innate compliance on the performance of a counterpulsation device

Cardiovascular disease (CVD) continues to be one of the top causes of mortality in the world. World Heart Organization (WHO) reported that in 2004, CVD contributed to almost 30% of death from estimated worldwide death figures of 58 million[1]. Heart failure treatment varies from lifestyle adjustment to heart transplantation; its aims are to reduce HF symptoms, prolong patient survival and minimize risk [2]. One alternative available in the market for HF treatment is Left Ventricular Assist Device (LVAD). Chronic Intermittent Mechanical Support (CIMS) device is a novel (LVAD) heart failure treatment using counterpulsation similar to Intra Aortic Balloon Pumps (IABP). However, the implantation site of the CIMS balloon is in the ascending aorta just distal to aortic valve contrasted with IABP in the descending aorta. Counterpulsation coupled with implantation close to the aortic valve enables comparable flow augmentation with reduced balloon volume. Two prototypes of the CIMS balloon were constructed using rapid prototyping: the straight-body model is a cylindrical tube with a silicone membrane lining with zero expansive compliance. The compliant-body model had a bulging structure that allowed the membrane to expand under native systolic pressure increasing the device’s static compliance to 1.5 mL/mmHg. This study examined the effect of device compliance and vascular compliance on counterpulsating flow augmentation. Both prototypes were tested on a two-element Windkessel model human mock circulatory loop (MCL). The devices were placed just distal to aortic valve and left coronary artery. The MCL mimicked HF with cardiac output of 3 L/min, left ventricular pressure of 85/15 mmHg, aortic pressure of 70/50 mmHg and left coronary artery flow rate of 66 mL/min. The mean arterial pressure (MAP) was calculated to be 57 mmHg. Arterial compliance was set to be1.25 mL/mmHg and 2.5 mL/mmHg. Inflation of the balloon was triggered at the dicrotic notch while deflation was at minimum aortic pressure prior to systole. Important haemodynamics parameters such as left ventricular pressure (LVP), aortic pressure (AoP), cardiac output (CO), left coronary artery flowrate (QcorMean), and dP (Peak aortic diastolic augmentation pressure – AoPmax ) were simultaneously recorded for both non-assisted mode and assisted mode. ANOVA was used to analyse the effect of both factors (balloon and arterial compliance) to flow augmentation. The results showed that for cardiac output and left coronary artery flowrate, there were significant difference between balloon and arterial compliance at p < 0.001. Cardiac output recorded maximum output at 18% for compliant body and stiff arterial compliance. Left coronary artery flowrate also recorded around 20% increase due to compliant body and stiffer arterial compliance. Resistance to blood ejection recorded highest difference for combination of straight body and stiffer arterial compliance. From these results it is clear that both balloon and arterial compliance are statistically significant factors for flow augmentation on peripheral artery and reduction of resistance. Although the result for resistance reduction was different from flow augmentation, these results serves as an important aspect which will influence the future design of the CIMS balloon and its control strategy. References: 1. Mathers C, Boerma T, Fat DM. The Global Burden of disease:2004 update. Geneva: World Heatlh Organization; 2008. 2. Jessup M, Brozena S. Heart Failure. N Engl J Med 2003;348:2007-18.

The development and investigation of a novel pulsatile heart assist device

Cardiovascular diseases (CVD) contributed to almost 30% of worldwide mortality; with heart failure being one class of CVD. One popular and widely available treatment for heart failure is the intra-aortic balloon pump (IABP). This heart assist device is used in counterpulsation to improve myocardial function by increasing coronary perfusion, and decreasing aortic end-diastolic pressure (i.e. the resistance to blood ejection from the heart). However, this device can only be used acutely, and patients are bedridden. The subject of this research is a novel heart assist treatment called the Chronic Intermittent Mechanical Support (CIMS) which was conceived to offer advantages of the IABP device chronically, whilst overcoming its disadvantages. The CIMS device comprises an implantable balloon pump, a percutaneous drive line, and a wearable driver console. The research here aims to determine the haemodynamic effect of balloon pump activation under in vitro conditions. A human mock circulatory loop (MCL) with systemic and coronary perfusion was constructed, capable of simulating various degrees of heart failure. Two prototypes of the CIMS balloon pump were made with varying stiffness. Several experimental factors (balloon inflation/deflation timing, Helium gas volume, arterial compliance, balloon pump stiffness and heart valve type) form the factorial design experiments. A simple modification to the MCL allowed flow visualisation experiments using video recording. Suitable statistical tests were used to analyse the data obtained from all experiments. Balloon inflation and deflation in the ascending aorta of the MCL yielded favourable results. The sudden balloon deflation caused the heart valve to open earlier, thus causing longer valve opening duration in a cardiac cycle. It was also found that pressure augmentation in diastole was significantly correlated with increased cardiac output and coronary flowrate. With an optimum combination (low arterial compliance and low balloon pump stiffness), systemic and coronary perfusions were increased by 18% and 21% respectively, while the aortic end-diastolic pressure (forward flow resistance) decreased by 17%. Consequently, the ratio of oxygen supply and demand to myocardium (endocardial viability ratio, EVR) increased between 33% and 75%. The increase was mostly attributed to diastolic augmentation rather than systolic unloading.

Local delivery of the KCa3.1 blocker, TRAM-34, prevents acute angioplasty-induced coronary smooth muscle phenotypic modulation and limits stenosis

Objective-We previously demonstrated that upregulation of intermediate-conductance Ca2+ -activated K+ channels (KCa 3.1) is necessary for mitogen-induced phenotypic modulation in isolated porcine coronary smooth muscle cells (SMCs). The objective of the present study was to determine the role of KCa3.1 in the regulation of coronary SMC phenotypic modulation in vivo using a swine model of postangioplasty restenosis. Methods and Results-Balloon angioplasty was performed on coronary arteries of swine using either noncoated or balloons coated with the specific KCa3.1 blocker TRAM-34. Expression of KCa3.1, c-jun, c-fos, repressor element-1 silencing transcription factor (REST), smooth muscle myosin heavy chain (SMMHC), and myocardin was measured using qRT-PCR in isolated medial cells 2 hours and 2 days postangioplasty. KCa3.1, c-jun, and c-fos mRNA levels were increased 2 hours postangioplasty, whereas REST expression decreased. SMMHC expression was unchanged at 2 hours, but decreased 2 days postangioplasty. Use of TRAM-34 coated balloons prevented KCa3.1 upregulation and REST downregulation at 2 hours, SMMHC and myocardin downregulation at 2 days, and attenuated subsequent restenosis 14 and 28 days postangioplasty. Immunohistochemical analysis demonstrated corresponding changes at the protein level. Conclusion-Blockade of KCa3.1 by delivery of TRAM-34 via balloon catheter prevented smooth muscle phenotypic modulation and limited subsequent restenosis. © 2008 American Heart Association, Inc.

Psychophysiological responses to visceral and somatic pain in functional chest pain identify clinically relevant pain clusters

Background: Despite chronic pain being a feature of functional chest pain (FCP) its experience is variable. The factors responsible for this variability remain unresolved. We aimed to address these knowledge gaps, hypothesizing that the psychophysiological profiles of FCP patients will be distinct from healthy subjects. Methods: 20 Rome III defined FCP patients (nine males, mean age 38.7 years, range 28-59 years) and 20 healthy age-, sex-, and ethnicity-matched controls (nine males, mean 38.2 years, range 24-49) had anxiety, depression, and personality traits measured. Subjects had sympathetic and parasympathetic nervous system parameters measured at baseline and continuously thereafter. Subjects received standardized somatic (nail bed pressure) and visceral (esophageal balloon distension) stimuli to pain tolerance. Venous blood was sampled for cortisol at baseline, post somatic pain and post visceral pain. Key Results: Patients had higher neuroticism, state and trait anxiety, and depression scores but lower extroversion scores vs controls (all p < 0.005). Patients tolerated less somatic (p < 0.0001) and visceral stimulus (p = 0.009) and had a higher cortisol at baseline, and following pain (all p < 0.001). At baseline, patients had a higher sympathetic tone (p = 0.04), whereas in response to pain they increased their parasympathetic tone (p ≤ 0.008). The amalgamating the data, we identified two psychophysiologically distinct 'pain clusters'. Patients were overrepresented in the cluster characterized by high neuroticism, trait anxiety, baseline cortisol, pain hypersensitivity, and parasympathetic response to pain (all p < 0.03). Conclusions & Inferences: In future, such delineations in FCP populations may facilitate individualization of treatment based on psychophysiological profiling. © 2013 John Wiley & Sons Ltd.

Nitric oxide-dependent bone marrow progenitor mobilization by carbon monoxide enhances endothelial repair after vascular injury

Carbon monoxide (CO) has emerged as a vascular homeostatic molecule that prevents balloon angioplasty-induced stenosis via antiproliferative effects on vascular smooth muscle cells. The effects of CO on reendothelialization have not been evaluated.

Anchoring effects in the development of false childhood memories

When people receive descriptions or doctored photos of events that never happened, they often come to remember those events. But if people receive both a description and a doctored photo, does the order in which they receive the information matter? We asked people to consider a description and a doctored photograph of a childhood hot air balloon ride, and we varied which medium they saw first. People who saw a description first reported more false images and memories than did people who saw a photo first, a result that fits with an anchoring account of false childhood memories. © 2010 The Psychonomic Society, Inc.

Human Security and Crime in Latin America: The political Capital and Political Impact of Criminal Groups and Belligerents Involved in Illicit Economies

Organized crime and illegal economies generate multiple threats to states and societies. But although the negative effects of high levels of pervasive street and organized crime on human security are clear, the relationships between human security, crime, illicit economies, and law enforcement are highly complex. By sponsoring illicit economies in areas of state weakness where legal economic opportunities and public goods are seriously lacking, both belligerent and criminal groups frequently enhance some elements of human security of the marginalized populations who depend on illicit economies for basic livelihoods. Even criminal groups without a political ideology often have an important political impact on the lives of communities and on their allegiance to the State. Criminal groups also have political agendas. Both belligerent and criminal groups can develop political capital through their sponsorship of illicit economies. The extent of their political capital is dependent on several factors. Efforts to defeat belligerent groups by decreasing their financial flows through suppression of an illicit economy are rarely effective. Such measures, in turn, increase the political capital of anti-State groups. The effectiveness of anti-money laundering measures (AML) also remains low and is often highly contingent on specific vulnerabilities of the target. The design of AML measures has other effects, such as on the size of a country’s informal economy. Multifaceted anti-crime strategies that combine law enforcement approaches with targeted socio-economic policies and efforts to improve public goods provision, including access to justice, are likely to be more effective in suppressing crime than tough nailed-fist approaches. For anti-crime policies to be effective, they often require a substantial, but politically-difficult concentration of resources in target areas. In the absence of effective law enforcement capacity, legalization and decriminalization policies of illicit economies are unlikely on their own to substantially reduce levels of criminality or to eliminate organized crime. Effective police reform, for several decades largely elusive in Latin America, is one of the most urgently needed policy reforms in the region. Such efforts need to be coupled with fundamental judicial and correctional systems reforms. Yet, regional approaches cannot obliterate the so-called balloon effect. If demand persists, even under intense law enforcement pressures, illicit economies will relocate to areas of weakest law enforcement, but they will not be eliminated.

426 ozonesonde profiles from Georg-Forster-Station

On 22 May 1985 the first balloon-borne ozonesonde was successfully launched by the staff of Georg-Forster-Station (70°46' S, 11°41' E). The following weekly ozone soundings mark the beginning of the continuous investigation of Germany to study the vertical ozone distribution in the southern hemisphere. In 1985 these ozone soundings have been the only record showing the change of vertical ozone distribution in the southern polar stratosphere in September and October. The regular ozone soundings from 1985 until 1992 are a valuable reference data set since the chemical ozone loss became a significant feature in the southern polar stratosphere. The balloon-borne soundings were performed at the upper air sounding facility of the neighbouring station Novolazarevskaya, just 2 km apart from Georg-Forster-Station. Till 1992, ozone soundings were taken without interruption. Afterwards, the ozone sounding program was moved to Neumayer-Station (70°39' S, 8°15' W) 750 km further west.

Grain size distribution and bulk chemistry of eolian dust

Atmospheric dust samples collected along a transect off the West African coast have been investigated for their physical (grain-size distribution), mineralogical, and chemical (major elements) composition. On the basis of these data the samples were grouped into sets of samples that most likely originated from the same source area. In addition, shipboard-collected atmospheric meteorological data, modeled 4-day back trajectories for each sampling day and location, and Total Ozone Mapping Spectrometer aerosol index data for the time period of dust collection (February-March 1998) were combined and used to reconstruct the sources of the groups of dust samples. On the basis of these data we were able to determine the provenance of the various dust samples. It appears that the bulk of the wind-blown sediments that are deposited in the proximal equatorial Atlantic Ocean are transported in the lower level (>~900 hPa) NE trade wind layer, which is a very dominant feature north of the Intertropical Convergence Zone (ITCZ). However, south of the surface expression of the ITCZ, down to 5°S, where surface winds are southwesterly, we still collected sediments that originated from the north and east, carried there by the NE trade wind layer, as well as by easterly winds from higher altitudes. The fact that the size of the wind-blown dust depends not only on the wind strength of the transporting agent but also on the distance to the source hampers a direct comparison of the dust's size distributions and measured wind strengths. However, a comparison between eolian dust and terrigenous sediments collected in three submarine sediment traps off the west coast of NW Africa shows that knowledge of the composition of eolian dust is a prerequisite for the interpretation of paleorecords obtained from sediment cores in the equatorial Atlantic.

Subfascial endoscopic perforator surgery (SEPS) in chronic venous insufficiency. A 14 years experience

Introduction. Subfascial Endoscopic Perforator Surgery (SEPS) enables the direct visualization and section of perforating veins. Morbidity and duration of hospitalization are both less than with conventional open surgery (Linton’s or Felder’s techniques). Patients and methods. A total of 322 legs from 285 patients with a mean age of 56 years (range 23-90) were treated at our Department from May 1996 to January 2010. In 309 cases, an endoscope (ETM Endoskopische Technik GmbH, Berlin, Germany) was introduced through a transverse incision approximately 1.5 cm in length and 10 cm from the tibial tuberosity, as with Linton’s technique. A spacemaker balloon dissector for SEPS, involving a second incision 6 cm from the first, was used in only 13 cases. Results. The procedure used in each case was decided on the basis of preoperative evaluation. SEPS and stripping were performed in 238 limbs (73.91%), SEPS and short stripping in 7 limbs (2.17%), SEPS and crossectomy in 51 limbs (15.84%), and SEPS alone in 26 limbs (8.07%). 103 patients presented a total of 158 trophic ulcers; the healing time was between 1 and 3 months, with a healing rate of 82.91% after 1 month and 98.73% after 3 months. Conclusion. Subfascial ligature of perforating veins is superior to sclerotherapy and minimally invasive suprafascial treatment for the treatment of CVI. It is easy to execute, minimally invasive and has few complications.

Small bowel adenocarcinoma. Two case reports

Introduction. Small bowel adenocarcinoma is a rare tumor, with a still not well studied tumorigenesis process, and non-specific symptoms that cause a delay in the diagnosis and consequently a worst outcome for the patient. Videocapsule endoscopy (VCE) and double-balloon enteroscopy (DBE) have revolutionized the diagnosis and management of patients with small bowel diseases. Surgery is the treatment of choice when feasible, while the chemotherapeutic approach is still not well standardized. Case reports. Two cases in 2 months (two women 52 and 72-yr-old) of primary bowel adenocarcinoma is reported. The site of the tumor was in jejunum, instead of the most common site in duodenum. The patients underwent DBE with biopsy and ink mark. Laparoscopic-assisted bowel segmental resection was performed. The pathologic diagnosis was primary jejunum adenocarcinoma. No post-operative mortality or significant morbidities were noted. Conclusion. The combination of DBE and laparocopic-assisted bowel surgery represents an ideal diagnostic and therapeutic method.