Migration integration policies as social determinants of health for highly educated immigrants in the United States.

Highly educated immigrants are part of the growing population of immigrants who are impacted by the increasingly hostile migration policies in the U.S. This qualitative study used a phenomenological approach and inductive reasoning to explore the possible impacts of migration integration policies as social determinants of health among this group. Data was collected through 31 semi-structured interviewees with highly educated immigrants who had an intention and interest to stay in the U.S. at the time of the interview. Data were analyzed using reflexive thematic analysis and four main themes emerged: (1) a life overshadowed by silent worries, (2) living through uncertainties and forced decisions as the result of migration integration policies, (3) complexities and challenges of living on a work visa, and (4) shared recommendations by interviewees. Documented narratives as part of this study suggest high rates of stress and anxiety as well as negative mental and physical health outcomes among the participants. Results also suggest high levels of internalized vulnerabilities. Participants shared that migration policies can be enhanced in the U.S. to support highly educated immigrants' growth by creating a better and more transparent communication system, replacing random review processes for applications with systematic procedures, creating expedited pathways to citizenship based on merit, and granting access to work as a basic human right.

Clinical and epidemiologic evaluation of a 2020 chikungunya outbreak in Cambodia.

BACKGROUND: In 2020, the Kingdom of Cambodia experienced a nationwide outbreak of chikungunya virus (CHIKV). Despite an increase in the frequency of outbreaks and expanding geographic range of CHIKV, diagnostic challenges remain, and limited surveillance data of sufficient granularity are available to characterize epidemiological profiles and disease dynamics of the virus. METHODS: An ongoing and long-standing cross-sectional study of acute undifferentiated febrile illness (AUFI) in Cambodia was leveraged to describe the disease epidemiology and characterize the clinical presentation of patients diagnosed with CHIKV during the 2020 outbreak. Participants presenting with AUFI symptoms at ten study locations provided acute and convalescent blood samples and were tested for CHIKV using a reverse transcription-polymerase chain reaction (RT-PCR) and serological diagnostic methods including IgM and IgG. Acute and follow-up clinical data were also collected. RESULTS: From 1194 participant blood samples tested, 331 (27.7%) positive CHIKV cases were detected. Most CHIKV positive individuals (280, 84.6%) reported having a fever 3 to 4 days prior to visiting a health facility. Symptoms including chills, joint pain, nausea, vomiting, and lesions were all statistically significant among CHIKV positive participants compared to CHIKV negative AUFI participants. Cough was negatively associated with CHIKV positive participants. Positivity proportions were significantly higher among adults compared to children. No significant difference was found in positivity proportion between rainy and dry seasons during the outbreak. Positive CHIKV cases were detected in all study site provinces, with the highest test positivity proportion recorded in the rural northeast province of Kratie. CONCLUSIONS: Surveillance data captured in this study provided a clinical and epidemiological characterization of positive CHIKV patients presenting at selected health facilities in Cambodia in 2020, and highlighted the widespread distribution of the outbreak, impacting both urban and rural locations. Findings also illustrated the importance of utilizing both RT-PCR and serological testing for effective CHIKV surveillance.

Description of a new species of Dermacentor Koch, 1844 (Acari: Ixodidae) from Laos and Thailand.

Dermacentor laothaiensis n. sp. (Acari: Ixodidae) is described based on adults ex wild boar and vegetation from Laos and Thailand. Adults of D. laothaiensis n. sp. are similar to those of D. bellulus (Schulze, 1935) and D. steini (Schulze, 1933) but can be distinguished by the conscutum shape, colour pattern of the conscutum and scutum, the density of punctations on the pseudoscutum and scutum and the shape of female genital structures.

Current and Future United States Light-Duty Vehicle Pathways: Cradle-to-Grave Lifecycle Greenhouse Gas Emissions and Economic Assessment.

This article presents a cradle-to-grave (C2G) assessment of greenhouse gas (GHG) emissions and costs for current (2015) and future (2025-2030) light-duty vehicles. The analysis addressed both fuel cycle and vehicle manufacturing cycle for the following vehicle types: gasoline and diesel internal combustion engine vehicles (ICEVs), flex fuel vehicles, compressed natural gas (CNG) vehicles, hybrid electric vehicles (HEVs), hydrogen fuel cell electric vehicles (FCEVs), battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). Gasoline ICEVs using current technology have C2G emissions of ∼450 gCO2e/mi (grams of carbon dioxide equivalents per mile), while C2G emissions from HEVs, PHEVs, H2 FCEVs, and BEVs range from 300-350 gCO2e/mi. Future vehicle efficiency gains are expected to reduce emissions to ∼350 gCO2/mi for ICEVs and ∼250 gCO2e/mi for HEVs, PHEVs, FCEVs, and BEVs. Utilizing low-carbon fuel pathways yields GHG reductions more than double those achieved by vehicle efficiency gains alone. Levelized costs of driving (LCDs) are in the range $0.25-$1.00/mi depending on time frame and vehicle-fuel technology. In all cases, vehicle cost represents the major (60-90%) contribution to LCDs. Currently, HEV and PHEV petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions, although they offer lower potential GHG reductions. The ranges of LCD and cost of avoided carbon are narrower for the future technology pathways, reflecting the expected economic competitiveness of these alternative vehicles and fuels.

Large-Scale Survey for Tickborne Bacteria, Khammouan Province, Laos.

We screened 768 tick pools containing 6,962 ticks from Khammouan Province, Laos, by using quantitative real-time PCR and identified Rickettsia spp., Ehrlichia spp., and Borrelia spp. Sequencing of Rickettsia spp.-positive and Borrelia spp.-positive pools provided evidence for distinct genotypes. Our results identified bacteria with human disease potential in ticks in Laos.

Clinical Presentation, Risk Factors, and Comparison of Laboratory Diagnostics for Seasonal Influenza Virus Among Cambodians From 2007 to 2020.

Background: Despite its global significance, challenges associated with understanding the epidemiology and accurately detecting, measuring, and characterizing the true burden of seasonal influenza remain in many resource-poor settings. Methods: A prospective observational study was conducted in Cambodia at 28 health facilities between 2007 and 2020 utilizing passive surveillance data of patients presenting with acute undifferentiated febrile illness (AUFI) to describe the prevalence of influenza A and B and characterize associated risk factors and symptoms using a questionnaire. A comparison of rapid influenza diagnostic tests (RIDTs) and real-time reverse transcription polymerase chain reaction (rRT-PCR) results was also conducted. Results: Of 30 586 total participants, 5634 (18.4%) tested positive for either influenza A or B, with 3557 (11.6%) positive for influenza A and 2288 (7.5%) positive for influenza B during the study. Influenza A and B were strongly associated with the rainy season (odds ratio [OR], 2.30; P < .001) and being from an urban area (OR, 1.45; P < .001). Analysis of individual symptoms identified cough (OR, 2.8; P < .001), chills (OR, 1.4; P < .001), and sore throat (OR, 1.4; P < .001) as having the strongest positive associations with influenza among patients with AUFI. Analysis comparing RIDTs and rRT-PCR calculated the overall sensitivity of rapid tests to be 0.492 (95% CI, 0.479-0.505) and specificity to be 0.993 (95% CI, 0.992-0.994) for both influenza type A and B. Conclusions: Findings from this 14-year study include describing the epidemiology of seasonal influenza over a prolonged time period and identifying key risk factors and clinical symptoms associated with infection; we also demonstrate the poor sensitivity of RIDTs in Cambodia.

Etiology and risk factors for diarrheal disease amongst rural and peri-urban populations in Cambodia, 2012-2018.

Diarrheal diseases are a leading cause of mortality and morbidity, disproportionally affecting persons residing in low and middle-income countries. Accessing high-resolution surveillance data to understand community-level etiology and risk remains challenging, particularly in remote and resource limited populations. A multi-year prospective cohort study was conducted in two rural and two peri-urban villages in Cambodia from 2012 to 2018 to describe the epidemiology and etiology of acute diarrheal diseases within the population. Suspected diarrheal episodes among participants were self-reported or detected via routine weekly household visits. Fresh stool and fecal swabs were tested, and acute-illness and follow-up participant questionnaires collected. Of 5027 enrolled participants, 1450 (28.8%) reported at least one diarrheal incident. A total of 4266 individual diarrhea case events were recorded. Diarrhea incidence rate was calculated to be 281.5 persons per 1000 population per year, with an event rate of 664.3 individual diarrhea events occurring per 1000 population per year. Pathogenic Escherichia coli, Aeromonas spp., and Plesiomonas shigelloides were the most prevalent bacterial infections identified. Hookworm and Strongyloides stercoralis were the predominant helminth species, while Blastocystis hominis and Giardia lamblia were the predominant protozoan species found. Norovirus genotype 2 was the predominant virus identified. Mixed infections of two or more pathogens were detected in 36.2% of positive cases. Risk analyses identified unemployed status increased diarrhea risk by 63% (HR = 1.63 [95% CI 1.46, 1.83]). Individuals without access to protected water sources or sanitation facilities were 59% (HR = 1.59 [95% CI 1.49, 1.69]) and 19% (HR = 1.19 [95% CI 1.12, 1.28]) greater risk of contracting diarrhea, respectively. Patient-level surveillance data captured in this long-term study has generated a unique spatiotemporal profile of diarrheal disease in Cambodia. Understanding etiologies, together with associated epidemiological and community-level risk, provides valuable public health insight to support effective planning and delivery of appropriate local population-targeted interventions.

Worms and welfare: Behavioural and physiological changes associated with gastrointestinal nematode parasitism in lambs.

Parasitism with gastrointestinal nematodes (GIN) is a worldwide issue impacting negatively on animal production, health, and welfare. Therefore, early diagnostic signs of parasitism are required to allow for timely interventions. The objective of this study was to evaluate the behavioural and physiological changes in lambs associated with GIN infection. We used 30, 8-month-old Romney-cross wethers, that were administered anthelmintics until faecal egg counts (FEC) were zero and housed in an indoor facility. The study lasted 9 weeks, which comprised a 3-week pre-treatment, and a 6-week treatment phase. Lambs were randomly assigned to one of two treatments (n = 15/treatment) trickle-dosed with: 1) 1500 infective third stage larvae (L3) three days/week for 6 weeks (27,000 total L3; challenged), or 2) water 3 days/week for 6 weeks (control). Within each pen there were 5 pairs of lambs (balanced for liveweight), with each pair comprising a challenged and control lamb. Blood, faecal, and saliva samples were collected 1 week pre-treatment and weekly for 6 weeks of treatment. Behaviour was observed (e.g., feeding, lying, standing) from video-camera recordings using scan sampling every 5 min for 8 h, 1 day pre-treatment and on the day immediately prior to physiological sampling across the 6-week treatment phase (7 days in total). Accelerometers were attached to each lamb to continuously monitor behaviour from 3 weeks pre-treatment and for the remainder of the study. Liveweight, body condition, faecal soiling and faecal consistency scoring were performed weekly as was lipidomic analysis of plasma samples. From week 2 of treatment, challenged lambs spent less time feeding and more time lying than control lambs until week 5 of treatment (P ≤ 0.01). At week 3 of treatment, elevated lipids (mainly triglycerides and phospholipids), loose faeces and faecal soiling around the anus were observed in challenged lambs compared with controls (P ≤ 0.05). From week 4 of treatment, FEC were elevated in the challenged compared to control lambs (P ≤ 0.05). There was also lower liveweight gain at 4 and 5 weeks of treatment in the challenged lambs compared with control lambs (P ≤ 0.05). These results show a clear timeline of changes in behaviour (e.g., feeding and lying), lipids such as triglycerides, and digestive function (e.g., faecal soiling) suggestive of GIN subclinical disease, which show promise for use in future studies on early identification of subclinical GIN parasitism in lambs.

The effect of corporate social responsibility on trustful relationship, supportive communication intention, and brand loyalty of ethnic halal restaurants.

The purpose of this study is to examine the relationships among CSR activities, brand trust, supportive communication intention, and brand loyalty in a halal restaurant franchise. This study attempts to understand the brand loyalty formation among foreigners visiting a halal ethnic restaurant franchise in South Korea. This study can contribute to the body of empirical evidence showing that CSR activities for different stakeholders can increase brand loyalty mediated by trust. Data were collected from an online survey platform, and visitors were recruited in one of the largest halal franchise restaurants in Korea. This study used a convenience sampling technique, and 225 questionnaires were used for final analysis. Structural equation modeling was likewise used in this research. The results reveal that CSR activities include four constructs: for communities, employees, the environment, and customers. These four dimensions reflect voluntary activities for core stakeholders and are positively associated with enhancement of trustful relationships between customers and restaurants. Among four CSR dimensions, CSR activities to employee are the most influential dimension, followed by CSR to community and to environment. However, the insignificant effect of CSR activities to customers on trust is found. Furthermore, trust positively influences supportive communication intention and brand loyalty. The proposed model of this present study can shed light on how to enhance brand loyalty and sustain trustful and emotional value of an ethnic restaurant franchise. The results can provide important implications for planning CSR engagement from a practical and managerial perspective in the restaurant industry.

The Genus Haemaphysalis (Acari: Ixodidae) in Laos: An Update of Species Records and a Review of Taxonomic Challenges.

Haemaphysalis Koch, 1844, is the largest genus of ticks in Southeast Asia, but little information is available concerning the species present in Laos. Recent research has yielded records for 10 Haemaphysalis species in Laos, including 5 new records, as well as 3 morphological entities of uncertain status. Further morphological and molecular studies are needed to clarify our taxonomic understanding of this genus in Southeast Asia.

A linkage map of the Asian tiger mosquito (Aedes albopictus) based on cDNA markers.

The Asian tiger mosquito, Aedes (Stegomyia) albopictus (Skuse), is an important vector of a number of arboviruses, and populations exhibit extreme variation in adaptive traits such as egg diapause, cold hardiness, and autogeny (ability to mature a batch of eggs without blood feeding). The genetic basis of some of these traits has been established, but lack of a high-resolution linkage map has prevented in-depth genetic analyses of the genes underlying these complex traits. We report here on the breeding of 4 F(1) intercross mapping families and the use of these to locate 35 cDNA markers to the A. albopictus linkage map. The present study increases the number of markers on the A. albopictus cDNA linkage map from 38 to 73 and the density of markers from 1 marker/5.7 cM to 1 marker/2.9 cM and adds 9, 16, and 10 markers to the 3 linkage groups, respectively. The overall lengths of the 3 linkage groups are 64.5, 76.5, and 71.6 cM, respectively, for a combined length of 212.6 cM. Despite conservation in the order of most genes among the 4 families and a previous mapping family, we found substantial heterogeneity in the amount of recombination among markers. This was most marked in linkage group I, which varied between 16.7 and 69.3 cM. A map integrating the results from these 4 families with an earlier cDNA linkage map is presented.

A genomic amplification affecting a carboxylesterase gene cluster confers organophosphate resistance in the mosquito Aedes aegypti: From genomic characterization to high-throughput field detection.

By altering gene expression and creating paralogs, genomic amplifications represent a key component of short-term adaptive processes. In insects, the use of insecticides can select gene amplifications causing an increased expression of detoxification enzymes, supporting the usefulness of these DNA markers for monitoring the dynamics of resistance alleles in the field. In this context, the present study aims to characterize a genomic amplification event associated with resistance to organophosphate insecticides in the mosquito Aedes aegypti and to develop a molecular assay to monitor the associated resistance alleles in the field. An experimental evolution experiment using a composite population from Laos supported the association between the over-transcription of multiple contiguous carboxylesterase genes on chromosome 2 and resistance to multiple organophosphate insecticides. Combining whole genome sequencing and qPCR on specific genes confirmed the presence of a ~100-Kb amplification spanning at least five carboxylesterase genes at this locus with the co-existence of multiple structural duplication haplotypes. Field data confirmed their circulation in South-East Asia and revealed high copy number polymorphism among and within populations suggesting a trade-off between this resistance mechanism and associated fitness costs. A dual-color multiplex TaqMan assay allowing the rapid detection and copy number quantification of this amplification event in Ae. aegypti was developed and validated on field populations. The routine use of this novel assay will improve the tracking of resistance alleles in this major arbovirus vector.

Role of counter-current chromatography in the modernisation of Chinese herbal medicines.

This review focuses on the growing popularity of using counter-current chromatography (CCC), with its liquid stationary phase, as one of the prime methods for isolating compounds from Chinese herbal medicines (CHMs). 198 publications are reviewed covering 108 different plant species from 56 plant families. These describe the isolation of 354 different molecules across a wide range of polarities, chemical classes and molecular weights (in the range 100-1000 Da). The suitability of CCC for the separation of active compounds from CHM, the phase systems used, how CCC has developed in China, compounds isolated, CCC instrumentation, performance, operational issues and innovations, all supported by detailed cross-referencing, are described. It is concluded that CCC is making an increasingly important contribution to the modernisation of Chinese herbal medicines.

Stress-Induced Immunomodulation in Low and High Reactive Sheep.

The objective of this study was to investigate the relationship between stress and temperament on the humoral immune response of ewes. Eighty ewes were allocated to one of four treatment groups in a 2 × 2 factorial design (n = 20 ewes/treatment): low (LR) and high (HR) reactive ewes were either exposed to no stress (CON) or were visually isolated (STRESS). Ewes remained in treatment pens for 23 h: heart rate was measured continuously, and saliva samples were collected prior to testing and at 0.5 h and 23 h for measurement of cortisol, CarLA IgA and total IgA concentrations. After the first 0.5 h, heart rate was elevated, and cortisol concentrations tended to be higher, whereas CarLa IgA concentrations were lower in STRESS than CON ewes. Similarly, after 23 h, cortisol concentrations remained elevated and CarLA IgA concentrations remained lower in STRESS than CON ewes. Interestingly, total IgA concentrations were not influenced by a 0.5 h or 23 h stressor. Overall, CarLA IgA concentrations were lower in HR than LR ewes at 0.5 h, but there was no significant stress × temperament interaction. Therefore, stress appears to have an immunosuppressive effect on CarLA IgA but not total IgA concentrations in ewes.

Six Nearly Complete Genome Segments of a Novel Reovirus Identified in Laotian Batflies.

As part of the characterization of viral communities of Laotian batflies, we report here the sequencing of six nearly complete genome segments of a novel reovirus identified in Laotian batflies that is distantly related to reoviruses recently reported in various Diptera species.

Distribution of insecticide resistance and mechanisms involved in the arbovirus vector Aedes aegypti in Laos and implication for vector control.

BACKGROUND: The yellow fever mosquito Aedes aegypti is the major vector of dengue, yellow fever, Zika, and Chikungunya viruses. Worldwide vector control is largely based on insecticide treatments but, unfortunately, vector control programs are facing operational challenges due to mosquitoes becoming resistant to commonly used insecticides. In Southeast Asia, resistance of Ae. aegypti to chemical insecticides has been documented in several countries but no data regarding insecticide resistance has been reported in Laos. To fill this gap, we assessed the insecticide resistance of 11 Ae. aegypti populations to larvicides and adulticides used in public health operations in the country. We also investigated the underlying molecular mechanisms associated with resistance, including target site mutations and detoxification enzymes putatively involved in metabolic resistance. METHODS AND RESULTS: Bioassays on adults and larvae collected in five provinces revealed various levels of resistance to organophosphates (malathion and temephos), organochlorine (DDT) and pyrethroids (permethrin and deltamethrin). Synergist bioassays showed a significant increased susceptibility of mosquitoes to insecticides after exposure to detoxification enzyme inhibitors. Biochemical assays confirmed these results by showing significant elevated activities of cytochrome P450 monooxygenases (P450), glutathione S-transferases (GST) and carboxylesterases (CCE) in adults. Two kdr mutations, V1016G and F1534C, were detected by qPCR at low and high frequency, respectively, in all populations tested. A significant negative association between the two kdr mutations was detected. No significant association between kdr mutations frequency (for both 1534C and 1016G) and survival rate to DDT or permethrin (P > 0.05) was detected. Gene Copy Number Variations (CNV) were detected for particular detoxification enzymes. At the population level, the presence of CNV affecting the carboxylesterase CCEAE3A and the two cytochrome P450 CYP6BB2 and CYP6P12 were significantly correlated to insecticide resistance. CONCLUSIONS: These results suggest that both kdr mutations and metabolic resistance mechanisms are present in Laos but their impact on phenotypic resistance may differ in proportion at the population or individual level. Molecular analyses suggest that CNV affecting CCEAE3A previously associated with temephos resistance is also associated with malathion resistance while CNV affecting CYP6BB2 and CYP6P12 are associated with pyrethroid and possibly DDT resistance. The presence of high levels of insecticide resistance in the main arbovirus vector in Laos is worrying and may have important implications for dengue vector control in the country.

How to realize the linear scale-up process for rapid purification using high-performance counter-current chromatography.

This study used the isolation of six constituents from Selaginella tamariscina as an example to demonstrate how to achieve rapid and predictable linear scale-up processes in both normal- and reversed-phase high-performance counter-current chromatography. After systematic optimization of solvent systems, sample concentration, sample loading volume, rotation speed and flow rate on the analytical Mini-DE centrifuge, the optimized parameters obtained were directly transferred to the preparative Midi-DE centrifuge, with nearly the same purities, resolutions and elution times but with 50 times the throughput. Amentoflavone (446.7 mg, 97.8%), robustaflavone (21.6 mg, 89.4%), bilobetin (80.7 mg, 92.7%), hinokiflavone (15.1 mg, 85.5%), isocryptomerin (34.8 mg, 89.6%) and an apigenin-diglucoside (46.3mg, 96.4%) were obtained with amounts and purities shown in parentheses as analysed by HPLC. The process, therefore, offers an efficient and rapid method of obtaining sufficient quantities of target compounds with significantly increased throughput after a linear scale-up.

Preparative separation of a terpenoid and alkaloids from Tripterygium wilfordii Hook. f. using high-performance counter-current chromatography. Comparison of various elution and operating strategies.

This paper describes how high-performance counter-current chromatography (HPCCC) was used strategically for the separation of Tripterygium wilfordii Hook. f. Due to the complexity of Chinese herbal medicines, the initial ethanol crude extract was fractionated into seven fractions using medium-pressure liquid chromatography (MPLC). One terpenoid (triptolide) and three alkaloids (peritassine A, wilforgine and wilforine) were further separated from one of the MPLC fractions. This fraction (1.25 g) yielded 8 mg of triptolide and 28 mg of peritassines A after one HPCCC column pass and 30 mg of wilforgine and 120 mg of wilforine after a second column pass with respective purities of 97%, 93.6%, 95.0% and 94.4%, which were determined by high-performance liquid chromatography (HPLC). This was a one-step HPCCC separation, using an n-hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) solvent system, where increases in theoretical plates have been sacrificed in favour of increasing throughput. Structures were identified by electrospray ionization mass spectrometry (ESI-MS), (1)H nuclear magnetic resonance ((1)H NMR) and (13)C nuclear magnetic resonance ((13)C NMR). Comparison of three different modes of eluting compounds retained in the liquid stationary phase: elution extrusion; dual mode and simple pump-out showed that simply pumping out the column contents at high flow gave better resolution and was eight times faster than the other two well-utilised methods. Triptolide and peritassines A were isolated for the first time from Tripterygium wilfordii Hook. f.

How changes in column geometry and packing ratio can increase sample load and throughput by a factor of fifty in Counter-Current Chromatography.

This paper builds on the fact that high aspect ratio rectilinear tubing columns of the same length and outside dimensions can double column efficiency. It demonstrates that further improvements in efficiency can be made by using rectilinear tubing columns with half the wall thickness thus replacing heavy PTFE with light solvent systems and producing lighter higher capacity columns. Increases in sample loading/throughput of up to 55x are demonstrated by comparing the separation of Honokiol and Magnolol using a Hexane: Ethyl Acetate: Methanol: Water (5:2:5:2) phase system with the new thin wall rectilinear column (56 mL, 30 mL/min, 2.1 g/h in 6.5 min.) with the original optimization performed using a conventional DE-Mini column (18 mL, 0.8 mm bore circular PTFE tubing, 2.5 mL/min, 0.038 g/h in 45 min.). Honokiol is currently going through first phase clinical trials as an anti-lung cancer therapy where preparative countercurrent chromatography was used for its manufacture. To be competitive in the future it is important for the technology to become more efficient. This is the first big step in that direction.

The effect of increasing centrifugal acceleration/force and flow rate for varying column aspect ratios on separation efficiency in Counter-Current Chromatography.

Increasing column/tubing aspect ratio has been shown in a feasibility study to improve column efficiency when operating in reversed phase mode. This paper contains a thorough investigation on how increases in mobile phase flow and centrifugal force field affect stationary phase retention and column efficiency (as measured by the resolution between adjacent peaks) for columns wound with rectilinear tubing of different aspect ratio. The study uses a Mini CCC instrument operating from 1500 to 2100 rpm (126-246 g) to compare three columns with the same cross-sectional area but different aspect ratio - rectangular horizontal (force field perpendicular to the flat side - aspect ratio 3.125); square (aspect ratio 1.0) and rectangular vertical (flat side parallel with force field - aspect ratio 0.32). Columns are compared by measuring stationary phase retention, resolution and normalized resolution for 3 different mobile phase flow rates 2, 4 and 8 ml/min in both normal phase and reversed phase modes. The results with rectilinear tubing are compared to conventional circular tubing with the same cross-sectional area. The results show that resolution increases with aspect ratio and that at the highest aspect ratio the highest flow rate can maintain a high efficiency only if the highest g-field of 246 g is used. When comparing the rectangular horizontal tubing which gave the best results with conventional circular tubing with the same cross-sectional area a 45% improvement was found in reversed phase mode and a 51% improvement in normal phase mode over the conventional circular cross-section tubing. In other words, a rectangular horizontally wound bobbin with half the length of tubing can achieve the same result as a circular one. These are very significant results for halving separation times analytically or enabling designers to produce new instruments of the same capacity with a much-reduced size.