Investigation of AlGaN/GaN high electron mobility transistor structures on 200-mm silicon (111) substrates employing different buffer layer configurations.

AlGaN/GaN high electron mobility transistor (HEMT) structures are grown on 200-mm diameter Si(111) substrates by using three different buffer layer configurations: (a) Thick-GaN/3 × {AlxGa1-xN}/AlN, (b) Thin-GaN/3 × {AlxGa1-xN}/AlN, and (c) Thin-GaN/AlN, so as to have crack-free and low-bow (<50 µm) wafer. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, high resolution-cross section transmission electron microscopy, optical microscopy, atomic-force microscopy, cathodoluminescence, Raman spectroscopy, X-ray diffraction (ω/2θ scan and symmetric/asymmetric ω scan (rocking curve scan), reciprocal space mapping) and Hall effect measurements are employed to study the structural, optical, and electrical properties of these AlGaN/GaN HEMT structures. The effects of buffer layer stacks (i.e. thickness and content) on defectivity, stress, and two-dimensional electron gas (2DEG) mobility and 2DEG concentration are reported. It is shown that 2DEG characteristics are heavily affected by the employed buffer layers between AlGaN/GaN HEMT structures and Si(111) substrates. Particularly, we report that in-plane stress in the GaN layer affects the 2DEG mobility and 2DEG carrier concentration significantly. Buffer layer engineering is shown to be essential for achieving high 2DEG mobility (>1800 cm2/V∙s) and 2DEG carrier concentration (>1.0 × 1013 cm-2) on Si(111) substrates.

Comparison of 2 Doses for ACTH Stimulation Testing in Dogs Suspected of or Treated for Hyperadrenocorticism.

BACKGROUND: Lowering the cosyntropin dose needed for ACTH stimulation would make the test more economical. OBJECTIVES: To compare the cortisol response to 1 and 5 µg/kg cosyntropin IV in dogs being screened for hyperadrenocorticism (HAC) and in dogs receiving trilostane or mitotane for pituitary-dependent HAC. ANIMALS: Healthy dogs (n = 10); client-owned dogs suspected of having HAC (n = 39) or being treated for pituitary-dependent HAC with mitotane (n = 12) or trilostane (n = 15). PROCEDURES: In this prospective study, healthy dogs had consecutive ACTH stimulation tests to ensure 2 tests could be performed in sequence. For the first test, cosyntropin (1 µg/kg IV) was administered; the second test was initiated 4 hours after the start of the first (5 µg/kg cosyntropin IV). Dogs suspected of having HAC or being treated with mitotane were tested as the healthy dogs. Dogs receiving trilostane treatment were tested on consecutive days at the same time post pill using the low dose on day 1. RESULTS: In dogs being treated with mitotane or trilostane, the 2 doses were pharmacodynamically equivalent (90% confidence interval, 85.1-108.2%; P = 0.014). However, in dogs suspected of having HAC, the doses were not pharmacodynamically equivalent (90% confidence interval, 73.2-92.8%; P = 0.37); furthermore, in 23% of the dogs, clinical interpretation of test results was different between the doses. CONCLUSIONS AND CLINICAL RELEVANCE: For dogs suspected of having HAC, 5 µg/kg cosyntropin IV is still recommended for ACTH stimulation testing. For dogs receiving mitotane or trilostane treatment, a dose of 1 µg/kg cosyntropin IV can be used.

Compact test apparatus for evaluation of flow erosion of marine coatings.

An apparatus designed and manufactured for evaluation of flow erosion of coatings or layers is presented in this paper. The setup was primarily designed for coatings intended to perform in dynamic marine environments but can be also used for evaluation using fresh water. The concept is based on an in-line flow test cell and modular design allowing good flexibility of varying testing parameters. The flow rate that can be achieved depends on the flow cell geometry and can reach 28 km/h (15 kn) with the presented setup. Temperature may be adjusted between 15 and 35 °C. Particle and metal ion filters are parts of this setup. The dimensions of the apparatus including all components do not exceed 2 m × 2 m × 2 m. The use of the apparatus is illustrated with the results of evaluation of self-polishing anti-fouling coatings and model, silicon wafer grafted layers.

Strong and superplastic nanoglass.

The strength-ductility tradeoff has been a common long-standing dilemma in materials science. For example, superplasticity with a tradeoff in strength has been reported for Cu50Zr50 nanoglass (NG) with grain sizes below 5 nm. Here we report an improvement in strength without sacrificing superplasticity in Cu50Zr50 NG by using a bimodal grain size distribution. Our results reveal that large grains impart high strength, which is in striking contrast to the physical origin of the improvement in strength reported in the traditional nanostructured metals/alloys. Furthermore, the mechanical properties of NG with a bimodal nanostructure depend critically upon the fraction of large grains. By increasing the fraction of the large grains, a transition from superplastic flow to failure by shear banding is clearly observed. We expect that these results will be useful in the development of a novel strong and superplastic NG.

Evaluation of thyroid-stimulating hormone, total thyroxine, and free thyroxine concentrations in hyperthyroid cats receiving methimazole treatment.

BACKGROUND: Iatrogenic hypothyroidism (IH) after treatment of hyperthyroidism can impair renal function. No study compared the efficacy of measurement of serum free thyroxine by equilibrium dialysis (fT4ed) or thyroid-stimulating hormone (TSH) concentrations for monitoring cats receiving methimazole. OBJECTIVES: To (1) compare the ability of total T4 and fT4ed concentrations in conjunction with TSH to define thyroid function in hyperthyroid cats receiving methimazole, (2) determine the prevalence of IH in cats receiving methimazole, and (3) examine the relationship between thyroid axis hormones and serum creatinine concentration. ANIMALS: One hundred and twenty-five serum samples from hyperthyroid cats receiving methimazole and total T4 concentrations ≤3.9 µg/dL. METHODS: Total T4, fT4ed, and TSH concentrations were measured to evaluate thyroid status and serum creatinine concentration was measured to assess renal function. A low total T4 or fT4ed concentration in combination with an increased TSH concentration defined IH. RESULTS: Forty-one cats (33%) had increased TSH concentrations. Of cats with total T4 and fT4ed concentrations below the reference range, 68% and 73%, respectively, had TSH concentrations above the reference range. Only 18% of cats with a normal TSH concentration had an increased serum creatinine concentrations as compared to 39% of those with increased TSH concentrations (P < .001). CONCLUSIONS: Free T4ed does not identify more cats with potential IH as compared to total T4. The IH prevalence was approximately 20%. Measurement of TSH may be more helpful in indicating that azotemia, if present, is at least in part related to IH. Investigation is needed to define TSH assay utility in identifying possible subclinical IH.

A numerical study of muco-ciliary transport under the condition of diseased cilia.

Structural and functional disorders of pulmonary cilia may result from genetic disorders and acquired insults. A two-dimensional numerical model based on the immersed boundary method coupled with the projection method is used to study the flow physics of muco-ciliary transport of the human respiratory tract under various abnormalities of cilia. The effects of the cilia beat pattern (CBP), ciliary length, immotile cilia, beating amplitude and uncoordinated beating of cilia are investigated. As expected, the mucus velocity decreases as the beating amplitude reduces. The windscreen wiper motion and rigid planar motion, which are two abnormal CBPs owing to genetic disorders, greatly reduce or almost stop the mucus transport. If the ciliary length varies from its standard length, the mucus velocity would decrease. The mucus velocity decreases rather linearly if the number of uniformly distributed immotile cilia increases. The numerical results show that the mucus velocity would be further reduced marginally when the uniformly distributed immotile cilia are rearranged as a cluster of immotile cilia. Furthermore, if half of the cilia are immotile and uniformly distributed and motile cilia beat at reduced amplitude, the incoordination between the active motile cilia would not significantly affect the mucus velocity.

Effect of trilostane and mitotane on aldosterone secretory reserve in dogs with pituitary-dependent hyperadrenocorticism.

BACKGROUND: Maximal aldosterone secretion in healthy dogs occurs 30 minutes postadrenocorticotropin (ACTH; 5 µg/kg IV) stimulation. The effect of trilostane and mitotane on aldosterone at that time is unknown. OBJECTIVES: To assess the effect of trilostane and mitotane in dogs with pituitary-dependent hyperadrenocorticism on aldosterone secretory reserve. To determine if aldosterone concentration correlates with electrolyte concentrations. ANIMALS: Serum collected from 79 client-owned dogs and 33 stored samples. METHODS: Client-owned dogs had ACTH stimulation tests with cortisol concentrations measured at 0 and 60 minutes and aldosterone concentrations measured at 0, 30, and 60 minutes. Stored samples had aldosterone concentrations measured at 0 and 60 minutes. Ten historical clinically healthy controls were included. All had basal sodium and potassium concentrations measured. RESULTS: The aldosterone concentrations in the mitotane- and trilostane-treated dogs at 30 and 60 minutes post-ACTH were significantly lower than in clinically healthy dogs; no significant difference was detected in aldosterone concentration between 30 and 60 minutes in treated dogs. However, a significantly higher percentage of dogs had decreased aldosterone secretory reserve detected at 30 minutes than at 60 minutes. At 30 minutes, decreased secretory reserve was detected in 49% and 78% of trilostane- and mitotane-treated dogs, respectively. No correlation was detected between aldosterone and serum electrolyte concentrations. CONCLUSIONS AND CLINICAL IMPORTANCE: Decreased aldosterone secretory reserve is common in trilostane- and mitotane-treated dogs; it cannot be predicted by measurement of serum electrolyte concentrations. Aldosterone concentration at 30 minutes post-ACTH stimulation identifies more dogs with decreased aldosterone secretory reserve than conventional testing at 60 minutes.

Effects of tibolone on osteoarthritis in ovariectomized rats: association with nociceptive pain behaviour.

BACKGROUND: To investigate the role of the synthetic steroid tibolone in the progression of osteoarthritis (OA) and in nociceptive behaviour in an experimental rat model of OA and ovariectomy (OVX)-induced osteoporosis. METHODS: OA was induced in Wistar rats by anterior cruciate ligament transection (ACLT) of the right knee. Osteoporosis was induced by bilateral OVX. Groups of animals were subjected to ACLT, OVX, sham or OVX + ACLT. In addition, two groups were subjected to OVX + ACLT surgeries and were orally administered 0.1 or 0.5 mg tibolone every other day for 14 consecutive weeks, starting 6 weeks after surgery. Nociceptive behaviours (secondary mechanical allodynia and weight-bearing distribution of the hind paws) were analysed prior to and every 3 weeks after surgery up to 24 weeks. At 24 weeks, histopathological studies were performed on the cartilage and synovial membranes of the knee joints, and bone metabolism was assessed by measuring serum concentrations of calcium, phosphorus and alkaline phosphatase. RESULTS: Rats undergoing ACLT or OVX + ACLT surgeries showed obvious OA changes in the joints. Animals subjected to ACLT + OVX and treated with tibolone had significantly less cartilage degeneration and synovitis and showed improved nociceptive tests compared with animals undergoing ACLT + OVX surgeries alone. OVX increased the severity of the ACLT-induced OA changes. There was a significant increase in serum alkaline phosphatase in the tibolone-treated ACLT + OVX groups. CONCLUSIONS: Treatment with tibolone attenuated the development of OA, concomitantly reduced nociception and increased serum alkaline phosphatase in ACLT + OVX rats.

Variation of atmospheric Be-7 in relation to PM concentrations.

In the present study, the influences of particulate matter (PM) and seasonal monsoons on (7)Be concentrations in surface air (CBe) are elucidated. The (7)Be and the corresponding PM concentrations in the air were monitored simultaneously throughout a 14-year period (1998-2011) in Hsinchu, Taiwan. During the autumn and winter seasons (Oct.-Feb.), both the PM and the (7)Be concentrations increased as a result of the northeasterly monsoon. In contrast, the lowest PM and (7)Be concentrations were observed in July and August. This timing is due to the occurrence of southwest monsoons, which carry air masses with low PM concentrations and are associated with depleted (7)Be from low latitudes. The activity concentration of (7)Be in the PM (APM) was used to explain the seasonal variations of (7)Be with respect to the PM concentrations. In contrast, APM is not sensitive enough to vary with the seasons. The air masses transported by the monsoons are believed to be partially mixed with the PM locally produced in Taiwan, which explains their seasonal variations. The (7)Be concentrations in surface air can be experimentally predicted from the PM concentrations based on CBe (mBq/m(3))=0.0767 PM (µg/m(3)) across seasons. The annual averages of the PM and (7)Be concentrations are 48.1 µg/m(3) and 3.7 mBq/m(3), respectively. The estimated CBe was either slightly overestimated or underestimated, depending on the season. The highest deviations occurred in July and August, when CBe was underestimated by 33%.

Impact of intraoperative rupture of the ovarian capsule on prognosis in patients with early-stage epithelial ovarian cancer: a meta-analysis.

BACKGROUND: The impact of intraoperative rupture on prognosis is controversial in early-stage epithelial ovarian cancer (EOC). Thus, we performed a meta-analysis to determine its impact and to evaluate factors to increase its risk. METHODS: We searched PubMed, Embase, and the Cochrane Library till May 2011, and 9 eligible studies including 2382 patients were evaluated. All patients were classified into three groups: no rupture; intraoperative rupture; preoperative involvement. RESULTS: Preoperative involvement decreased progression-free survival when compared with intraoperative rupture (PFS; HR, 1.47; 95% CI, 1.01-2.14), which also showed poorer PFS than no rupture (HR, 2.41; 95% CI, 1.74-3.33). Although preoperative involvement reduced PFS when compared with intraoperative rupture (HR, 2.63; 95% CI, 1.11-6.20), there was no difference in it between intraoperative rupture and no rupture in patients who underwent complete surgical staging operation and adjuvant platinum-based chemotherapy if needed (HR, 1.49; 95% CI, 0.45-4.95). Furthermore, adhesion to adjacent tissues, grade 2 or 3 disease were more common (ORs, 2.01 and 2.47; 95% CIs, 1.20-3.37 and 1.12-5.46), whereas mucinous tumor was less frequent (OR, 0.51; 95% CI, 0.37-0.72) in intraoperative rupture than in no rupture. CONCLUSIONS: Intraoperative rupture may not decrease PFS when compared with no rupture in patients with early-stage EOC who underwent complete surgical staging operation and adjuvant platinum-based chemotherapy. Furthermore, more adhesion to adjacent tissues and grade 2 or 3 disease, and less mucinous tumor are expected to increase the risk of intraoperative rupture.

Modelling porous structures by penalty approach in the extended finite element method.

In this study, a methodology for studying porous structures was proposed. The extended finite element method (XFEM) in conjunction with a penalty approach was used to model the porous structures. The holes were considered to have very small Young's modulus, thus they could be treated as inclusions in a matrix. The level set method was applied to describe the internal boundaries of the holes. Various porous structures were investigated. A practical example of the porous structures, which was the microstructure of a trabecular bone, was examined to show the capability of the proposed methodology. The aim of the study was to demonstrate that various complicated porous structures can be modelled efficiently by the XFEM without any major modification to the existing formula.

4-O-methylhonokiol, a PPARγ agonist, inhibits prostate tumour growth: p21-mediated suppression of NF-κB activity.

BACKGROUND AND PURPOSE: The effects of 4-O-methylhonokiol (MH), a constituent of Magnolia officinalis, were investigated on human prostate cancer cells and its mechanism of action elucidated. EXPERIMENTAL APPROACH: The anti-cancer effects of MH were examined in prostate cancer and normal cells. The effects were validated in vivo using a mouse xenograft model. KEY RESULTS: MH increased the expression of PPARγ in prostate PC-3 and LNCap cells. The pull-down assay and molecular docking study indicated that MH directly binds to PPARγ. MH also increased transcriptional activity of PPARγ but decreased NF-κB activity. MH inhibited the growth of human prostate cancer cells, an effect attenuated by the PPARγ antagonist GW9662. MH induced apoptotic cell death and this was related to G(0) -G(1) phase cell cycle arrest. MH increased the expression of the cell cycle regulator p21, and apoptotic proteins, whereas it decreased phosphorylation of Rb and anti-apoptotic proteins. Transfection of PC3 cells with p21 siRNA or a p21 mutant plasmid on the cyclin D1/ cycline-dependent kinase 4 binding site abolished the effects of MH on cell growth, cell viability and related protein expression. In the animal studies, MH inhibited tumour growth, NF-κB activity and expression of anti-apoptotic proteins, whereas it increased the transcriptional activity and expression of PPARγ, and the expression of apoptotic proteins and p21 in tumour tissues. CONCLUSIONS AND IMPLICATION: MH inhibits growth of human prostate cancer cells through activation of PPARγ, suppression of NF-κB and arrest of the cell cycle. Thus, MH might be a useful tool for treatment of prostate cancer.

Optofluidic variable-focus lenses for light manipulation.

This paper presents a planar optofluidic lens for light manipulation utilizing a combination of optofluidic biconvex lens with micromixer. Three light manipulation techniques including tunable optical diverging, collimating and focusing are realized by altering the refractive index of the optofluidic variable-focus lenses formed by solid polydimethylsiloxane (PDMS) walls and tunable liquid lens body. The optical power from the laser input can be increased or decreased with the tuning of the variable-focus lenses' refractive indexes. The optical power adjustment capabilities are demonstrated and characterized. The combinations of benefits of all lens' optical manipulation capabilities, greater mechanical stability, significant increase of optofluidic device's life time and seamless integration with other lab-on-a-chip functionalities provide a promising and versatile optofluidic compartment to integrate with lab-on-a-chip excitation and sensing applications. Optofluidic lens-including system for tunable fluorescence sensing is demonstrated showing 186% increase in detected fluorescence intensity.

Inhibition of Bax protects neuronal cells from oligomeric Aß neurotoxicity.

Although oligomeric ß-amyloid (Aß) has been suggested to have an important role in Alzheimer disease (AD), the mechanism(s) of how Aß induces neuronal cell death has not been fully identified. The balance of pro- and anti-apoptotic Bcl-2 family proteins (e.g., Bcl-2 and Bcl-w versus Bad, Bim and Bax) has been known to have a role in neuronal cell death and, importantly, expression levels of these proteins are reportedly altered in the vulnerable neurons in AD. However, the roles of apoptotic proteins in oligomeric Aß-induced cell death remain unclear in vivo or in more physiologically relevant models. In addition, no study to date has examined whether Bax is required for the toxicity of oligomeric Aß. Here, we found that treatment with oligomeric Aß increased Bim levels but decreased Bcl-2 levels, leading to the activation of Bax and neuronal cell death in hippocampal slice culture and in vivo. Furthermore, the inhibition of Bax activity either by Bax-inhibiting peptide or bax gene knockout significantly prevented oligomeric Aß-induced neuronal cell death. These findings are first to demonstrate that Bax has an essential role in oligomeric Aß-induced neuronal cell death, and that the targeting of Bax may be a therapeutic approach for AD.

Drug delivery in the nasal cavity after functional endoscopic sinus surgery: a computational fluid dynamics study.

BACKGROUND: Intranasal medication is commonly used for nasal disease. However, there are no clear specifications for intranasal medication delivery after functional endoscopic sinus surgery. METHODS: A three-dimensional model of the nasal cavity was constructed from computed tomography scans of an adult Chinese male who had previously undergone functional endoscopic sinus surgery in the right nasal cavity. Computational fluid dynamic simulations modelled airflow and particle deposition, based on discrete phase models. RESULTS: In the right nasal cavity, more particles passed through the upper dorsal region, around the surgical area, and streamed into the right maxillary sinus region. In the left cavity, particles were distributed more regularly and uniformly in the ventral region around the inferior turbinate. A lower inspiratory airflow rate and smaller initial particle velocity assisted particle deposition within the right maxillary sinus cavity. In the right nasal cavity, the optimal particle diameter was approximately 10(-5) m for maxillary sinus cavity deposition and 3 × 10(-6) m for bottom region deposition. In the right nasal cavity, altered back head tilt angles enhanced particle deposition in the top region of the surgical area, and altered right side head tilt angles helped enhance maxillary sinus cavity deposition. CONCLUSION: This model indicates that a moderate inspiratory airflow rate and a particle diameter of approximately 10(-5) m should improve intranasal medication deposition into the maxillary sinus cavity following functional endoscopic sinus surgery.

Singapore cancer trends in the last decade.

In this review, we examine the trends in cancer incidence, mortality and survival in the last decade, using published data from the Singapore Cancer Registry in the period 1998 to 2009. While overall cancer incidences have remained stable, overall cancer mortality rates have declined for both genders. Thus, it is not surprising that there was an improvement in cancer survival. A steady decrease in lung cancer among males and females was observed, thereby leading to a drop in its cancer ranking. In the last five years, the most frequently occurring cancer was colorectal cancer among the male population and breast cancer among females. Survival for both cancers remained relatively optimistic. There is good reason to pay special attention to colorectal cancer due to its high frequency of occurrence among the Singapore population and because it is amenable to early detection via screening.

Deposition of beryllium-7 in Hsinchu, Taiwan.

In the present study, factors that influence the distribution and variation of (7)Be in Hsinchu, Taiwan were elucidated. The (7)Be activity including the deposition flux and air concentration was continuously monitored and recorded throughout a 15-year period (1996-2010). To explain the observed variability in the (7)Be activity over time, air concentration and deposition flux of (7)Be were correlated to rainfall and solar activity. The monthly average deposition flux and air concentration of (7)Be were inversely related to solar activity with the 11-year cycle and were not strongly correlated to rainfall. The highest seasonal deposition flux of (7)Be occurred in March, which is commonly referred to as the spring maximum, due to air-mass mixing processes in the troposphere. The air concentration of (7)Be was seasonally variable and was significantly affected by monsoons. The lowest deposition flux and air concentration of (7)Be were observed in July and August due to the occurrence of southwest monsoons from low latitudes, which carry air masses with low concentrations of (7)Be. The deposition flux was enhanced by precipitation, which increased the deposition velocity, transferring more (7)Be from the troposphere to the ground. The fraction of dry to total deposition varied seasonally and was equal to 9.86%, on average.

Smoking cessation and lung cancer risk in an Asian population: findings from the Singapore Chinese Health Study.

BACKGROUND: Smoking cessation is an important strategy for reducing the harmful effects of tobacco, particularly in the prevention of lung cancer; however, prospective data on the impact of smoking cessation on lung cancer risk in Asian populations are limited. METHODS: We studied a population-based cohort of Chinese men and women aged 45-74 years--participants of the Singapore Chinese Health Study. Information on smoking, lifestyle and dietary habits was collected at the time of recruitment in 1993-1998; and smoking status was assessed again at a second interview in 1999-2004 (mean interval 5.8 years). Participants were followed up to 31 December 2007, and incident cases of lung cancer were ascertained by linkage with population-wide registries. RESULTS: Among 45,900 participants, there were 463 incident cases of lung cancer. Relative to current smokers, those who quit smoking subsequent to baseline assessment had a 28% decrease in the risk of lung cancer (adjusted hazard ratio (HR) 0.72; 95% CI (95% confidence interval): 0.53-0.98). The risk was less than half in ex-smokers who had quit before the first interview and maintained their status (HR 0.42; 95% CI: 0.32-0.56). CONCLUSIONS: Reduction in lung cancer incidence with smoking cessation in Asian populations is substantial and can be observed within a few years after quitting.

Finite element analysis for the evaluation of protective functions of helmets against ballistic impact.

The ballistic impact of a human head model protected by a Personnel Armor System Ground Troops Kevlar® helmet is analysed using the finite element method. The emphasis is to examine the effect of the interior cushioning system as a shock absorber in mitigating ballistic impact to the head. The simulations of the frontal and side impacts of the full metal jacket (FMJ) and fragment-simulating projectile (FSP) were carried out using LS-DYNA. It was found that the Kevlar® helmet with its interior nylon and leather strap was able to defeat both the FMJ and FSP without the projectiles penetrating the helmet. However, the head injuries caused by the FMJ impact can be fatal due to the high stiffness of the interior strap. The bulge section at the side of the Kevlar® helmet had more room for deformation that resulted in less serious head injuries.

A review of the implications of computational fluid dynamic studies on nasal airflow and physiology.

BACKGROUND: Computational fluid dynamics has been adapted to studying nasal aerodynamics. AIM: To review current literature on CFD studies, with an emphasis on normal nasal airflow, the impact of sinonasal pathology on airflow, and implications on nasal physiology. The objective is to provide the rhinologists with a greater understanding of nasal airflow and how symptomatology of sinonasal disease may be explained via CFD simulations. RESULTS: The nasal valve region redirects inspiratory airstreams over the inferior turbinate in a high turbulent kinetic energy, which is important in heat and moisture exchange. The bulk of airflow occurs in the common meatus with small streams traversing the olfactory groove, increasing during sniffing. Septal deviation and enlarged inferior turbinate causes redistribution of airflow, changes in intranasal pressure and increased turbulence. High velocity airflow and wall shear stress at the septal perforation causes desiccation and mucosal damage. The airflow within an atrophic nasal cavity is predominantly laminar with minimal contact with nasal mucosa. The inferior turbinate is an important organ for air conditioning and preservation during surgery is highlighted. CONCLUSIONS: Despite some limitations of CFD simulations, this technology has improved understanding of the complex nasal anatomy and the implications of disease and surgery on physiology.