Sorption of Carbon Dioxide and Nitrogen on Porous Hyper-Cross-Linked Aromatic Polymers: Effect of Textural Properties, Composition, and Electrostatic Interactions.

Porous hyper-cross-linked aromatic polymers are one of the emerging classes of porous organic polymers with the potential for industrial application. Four different porous polymeric materials have been prepared using different precursors (indole, pyrene, carbazole, and naphthalene), and the composition and textural properties were analyzed. The materials were characterized in detail using different physicochemical techniques like scanning electron microscopy, transmission electron microscopy, nitrogen adsorption at 77 K, Fourier transform infrared spectroscopy, X-ray diffraction, etc. The effect of textural properties and nitrogen species on carbon dioxide and nitrogen adsorption capacities and selectivity was studied and discussed. The carbon dioxide and nitrogen adsorption capacities were measured using a volumetric gas adsorption system. The adsorption data were fitted into different adsorption models, and the ideal absorbed solution theory was used to calculate adsorption selectivity. Among the studied samples, POP-4 shows the highest carbon dioxide and nitrogen adsorption capacities. While POP-1 shows maximum CO2/N2 selectivity of 78.0 at 298 K and 1 bar pressure. It is observed that ultra-micropores, which are present in the prepared materials but not measured during conventional surface area measurement via nitrogen adsorption at 77 K, play a very important role in carbon dioxide adsorption capacity and determining the carbon dioxide selectivity over nitrogen. Surface nitrogen also increases the CO2 selectivity in the dual mode by increasing carbon dioxide adsorption via the acid-base interaction as well as by decreasing nitrogen adsorption due to N-N repulsion.

Fabrication of Alkaline Electrolyzer Using Ni@MWCNT as an Effective Electrocatalyst and Composite Anion Exchange Membrane.

Here, we report the synthesis of nickel nanoparticles thermally encapsulated in multiwalled carbon nanotubes (MWCNTs) and its utility in alkaline water splitting by combining with composite thermoset anion-exchange membrane. Ni@MWCNT displayed both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). It provided 10 mA cm-2 current density at an overpotential of 300 mV for OER and 254 mV for HER on a glassy carbon electrode, respectively. Base-catalyzed N-methly-4-piperidone-formaldehyde-based prepolymer was grafted on to poly(vinyl alcohol) and cross-linked via thermal annealing followed by quaternization using methyl iodide to obtain thermoset anion exchange membrane (NMPi). Composite NMPi membranes were synthesized using additives tetraethyl orthosilicate (TEOS) and zirconium oxychloride. The water splitting performance on the fabricated membrane electrode assembly was tested and compared with commercially available Neosepta membrane. The obtained faradic efficacy of the water splitting was 94.33% for ZrO2-NMPi membrane followed by 80.23%, 77.70%, and 65.10% for SiO2-NMPi, NMPi, and Neosepta membranes, respectively. The best membrane ZrO2-NMPi achieved maximum current density of ∼0.776 A cm-2 in 5 M KOH electrolyte at 80 °C and 2 V applied constant voltage. The excellent alkaline stability of MEA indicates its potential utility in hydrogen generation applications.

A Mechanistic Review on Plant-derived Natural Inhibitors of Human Coronaviruses with Emphasis on SARS-COV-1 and SARS-COV-2.

Coronaviruses have been receiving continuous attention worldwide as they have caused a serious threat to global public health. This group of viruses is named so as they exhibit characteristic crown-like spikes on their protein coat. SARS-CoV-2, a type of coronavirus that emerged in 2019, causes severe infection in the lower respiratory tract of humans and is often fatal in immunocompromised individuals. No medications have been approved so far for the direct treatment of SARS-CoV-2 infection, and the currently available treatment options rely on relieving the symptoms. The medicinal plants occurring in nature serve as a rich source of active ingredients that could be utilized for developing pharmacopeial and non-pharmacopeial/synthetic drugs with antiviral properties. Compounds obtained from certain plants have been used for directly and selectively inhibiting different coronaviruses, including SARS-CoV, MERS-CoV, and SARS-CoV-2. The present review discusses the potential natural inhibitors against the highly pathogenic human coronaviruses, with a systematic elaboration on the possible mechanisms of action of these natural compounds while acting in the different stages of the life cycle of coronaviruses. Moreover, through a comprehensive exploration of the existing literature in this regard, the importance of such compounds in the research and development of effective and safe antiviral agents is discussed. We focused on the mechanism of action of several natural compounds along with their target of action. In addition, the immunomodulatory effects of these active components in the context of human health are elucidated. Finally, it is suggested that the use of traditional medicinal plants is a novel and feasible remedial strategy against human coronaviruses.

Low-Voltage Nongassing Electroosmotic Pump and Infusion Device with Polyoxometalate-Encapsulated Carbon Nanotubes.

A low-voltage nongassing electroosmotic pump was assembled by sandwiching a silica frit between two carbon paper electrodes that were dip-coated with a paste consisting of phosphomolybdic acid/phosphotungstic acid (PMA/PTA)-encapsulated multiwalled carbon nanotubes (MWCNTs) and Nafion. The PMA/PTA encapsulation was a combined effect of their thermomigration and nanocapillary action in MWCNTs. The encapsulated MWCNTs retained desirable redox and charge transfer characteristics of PMA/PTA. The stable voltammogram in 1 M H2SO4 solution exhibited 77% charge retention. A total of three different possible pump configurations, namely, PUMP-I = PMA//SiO2//PMA, PUMP-II = PTA//SiO2//PTA, and PUMP-III = PMA//SiO2//PTA were put together. They are in the sequence of the anode, silica frit, and cathode. All pumps showed a linear dependence on the flow rate with a minimum operating voltage of 1 V, which is well below the thermodynamic potential of water splitting. PUMP-I provided an electroosmotic flux of 43.57 µLmin-1 V-1 cm-2 that matched the requirement of an infusion device like an insulin pump. The device was fabricated and its applicability has been demonstrated by delivering ∼1.8 mL of water at a 10 ± 2 µLmin-1 flow rate at 2 V constant applied voltage over a period of 3 h. Such a wearable device can be programed to deliver model insulin or pain medication drugs for chronic diseases.

Comparative analysis of paediatric and adult surgically drained dental infections at a university teaching hospital.

In the United Kingdom (UK) the estimated prevalence of dental infection involving the supporting bone is 2%, and from 2014-2015 there were 2281 admissions in England alone due to dental abscess. We undertook an analysis of 184 dental abscesses that required surgical drainage, as there is surprisingly little in the literature on the subject. This was a retrospective study of 184 consecutive patients with dental abscesses who were admitted between January 2016 and September 2019. On admission, all patients had orthopantomograms (OPG) and baseline blood tests. Surgical drainage was performed under a general or local anaesthetic and a pus swab sent for culture and sensitivity. The submandibular space was the most commonly involved site and paediatric patients most often presented with buccal space abscesses. A lower molar tooth was the cause in 132 patients. White blood cells (WBC) and C-reactive protein (CRP) were both raised in 63.6% (n=117), but were normal in 4.9% (n=9). The remaining patients had either raised WBC (2.7%) or CRP (28.8%). Streptococcus milleri was the most common organism isolated in 66.6% (n=42). There was no association between CRP or WBC values and duration of hospital stay. Paediatric patients had a shorter duration of admission (1.96 days vs 2.81 days) and significantly lower CRP values (120.9 vs 45.7; p=0.001). The submandibular space was the commonest site involved and mandibular molars the most frequent source of infection. An elevated CRP value appeared to be a more sensitive indicator of infection in this study population. Adult and paediatric patients present in a different manner.

Alkaline all iron redox flow battery with a polyethylene/poly(styrene-co-divinylbenzene) interpolymer cation-exchange membrane.

This work describes the suitability of a polyethylene styrene-DVB based interpolymer cation exchange membrane for use in a highly alkaline redox flow battery (RFB) with a [Fe(TEA)OH]2-/[Fe(TEA)OH]- and Fe(CN)6 3-/Fe(CN)6 4- redox couple. The alkaline stability of the membrane for 1440 h was evaluated in 5 N NaOH containing a 200 mM Fe(CN)6 3-/Fe(CN)6 4- redox couple. It was assessed according to the changes in the electrochemical and physicochemical properties. The performance of the membrane was evaluated over 40 charge-discharge cycles at a current density of 5 mA cm-2 current in a designed RFB cell. The obtained average coulombic efficiency (CE) was 92%, energy efficiency (EE) was 75%, voltage efficiency (VE) was 82% and volumetric efficiency was 34%. Under identical experimental conditions, the values of CE, EE, and VE for Nafion®-112 were 99%, 75%, and 76%, respectively. These results indicate the suitability of the polyethylene styrene-DVB based interpolymer cation exchange membrane for use in an alkaline RFB.

A non-gassing electroosmotic pump with sandwich of poly(2-ethyl aniline)-Prussian blue nanocomposite and PVDF membrane.

Low voltage, non-gassing electroosmotic pump (EOP) was assembled with poly(2-ethyl aniline) (EPANI)-Prussian blue nanocomposite electrode and commercially available hydrophilic PVDF membranes. The nanocomposite material combines excellent oxidation/reduction capacity of EPANI with exceptional stability by shuttling of proton between Prussian blue nanoparticles and EPANI redox matrix. The flow rate was highly dependent on the electrode composition but it was linear with applied voltage. The flow rate at 5 V for different nanocomposite, EPANI, EPANI-A, EPANI-B, and EPANI-C were 127.29, 187.41, 148.51, and 95.47 µL/min cm2 , respectively, which increases substantially with increase in the Prussian blue content. The obtained best electro osmotic flux was 43 µL/min/V/cm2 for EPANI-A. It was higher than most of the EOP assembled using polyquinone and polyanthraquinone redox polymers. The assembled EOP remained exceptionally stable until the electrode charge capacity was fully utilized. The best EOP produces a maximum stall pressure of 1.2 kPa at 2 V. These characteristics make it suitable for a variety of microfluidic/device applications.

Study of therapeutic efficacy of febuxostat in chronic kidney disease stage IIIA to stage VD.

Hyperuricemia [serum uric acid (SUA) >7.0 mg/dL] which is common in chronic renal diseases is associated with augmented vascular events. In addition to nonpharmacological therapy, hypouricosuric drugs reduce UA levels. The current study was a prospective observational study of six months duration November 2016 to April 2017 done to determine the efficacy of febuxostat in patients with hyperuricemia in chronic kidney disease (CKD) stage G3a to G5 and to correlate any association with reduction of hypertension, improvement in glomerular filtration rate (GFR), and reduction in comorbidities. The study was carried out at the Department of Nephrology, Owaisi Hospital and Research Center, Hyderabad. One hundred and ten patients were screened, of which 53 patients wherein stage G3a to G5 were recruited and SUA levels were obtained after inclusion criteria. SUA >6.0 in females and 7.0 in males were recruited. The drug febuxostat 40 mg was given once day to all patients with stage G3a to G5D with elevate uric acid levels >7.0 in males and more than 6.0 in females and three samples of UA were obtained monthly. The mean of GFR, blood pressure (BP), and SUA levels were obtained before and after the therapy. Of the 53 patients, males were 32 (60.3%), and females were 21 (39.6%). Mean age of the patients were 36.5 years. Mean UA levels before the start of febuxostat therapy were 8.6, and after adding febuxostat, it was 5.10 at the end of the third visit. The mean BP drop was 7.2 ± 2.1 mm in systolic BP (from 154-147 mm Hg) and diastolic BP drop was 93 ± 2.5 mm Hg (5.1 mm Hg). The mean GFR improved from 50.3 to 53.3 mL/min after the start of febuxostat. Febuxostat in asymptomatic CKD patients improves UA levels, BP and estimated GFR at low dose without any adverse events and no cardiac-related events.

Clinical and histological correlation of diabetic nephropathy.

Renal failure in diabetes is a common cause of renal replacement therapy. The affected kidney goes through various changes in all compartments progressively. The classification of diabetic nephropathy is based on glomerular lesions and displays a heterogeneous morphology. Abnormalities in tubulointerstitial and vascular compartments are important in assessing the outcome of these patients. We applied the new pathologic classification of diabetic nephropathy by Tervaert et al to classify the renal damage in diabetes. This is a prospective study over two years. We analyzed 74 renal biopsies in diabetic patients, both type-1 and type-2. Indications for biopsy were rapid onset of proteinuria, absence of retinopathy, presence of hematuria, active urine sediment, and rapid unexplained deterioration of renal function. Biopsy was done to rule out nondiabetic renal disease or any other associated pathology with diabetic nephropathy. In our study, 53 patients were male and 21 patients were female. Age ranged from 27 to 82 years. The mean ± standard deviation age at the time of the biopsy was 54.09 ± 11.59 years. Mean duration of diabetes was 10.2 years. Proteinuria ranged from 1 to 26 g. Type-111 histopathological lesion was the most common lesion observed in our series. There was a correlation between the degree of tubulo-interstitial damage with renal function. There was no correlation between the fundal changes and degree of proteinuria with the histological class of diabetic nephropathy. Application of the classification by Tervaert et al to diabetic lesions reduces the inter-observer variability and also helps in prognosticating and management of patients.

Graphitic carbon coupled poly(anthraquinone) for proton shuttle flow-in-a-cell application.

Coupled electron and proton transport are an integral part of non-gassing electro-osmotic pumps (EOP). The kinetics of the electrode limits the kinetics of the electron transfer and hence the flow. This is observed in the present study with newly synthesized graphitic carbon covalently coupled to poly(anthraquinone) (PAQ). When EOP with identical electrodes were assembled, proton shuttle maintained the reversible flow, which was linearly dependent on the ks values. A Laviron plot was used to calculate the electron-transfer rate constant ks and transfer coefficient α, and their linear dependency on content of graphitic carbon was observed. The best ks value obtained was 0.67 s-1 for 15PAQ. The sandwich-type flow-in-a-cell showed the best result of ∼40 µL min-1 cm-1 V-1 electro-osmotic flux for 15PAQ. It reveals that a balanced combination of graphitic carbon and PAQ is the prime requirement for high-performance electrode materials to be used in microfluidic devices and energy applications.

Focal segmental glomerulosclerosis in renal allografts: Is it possible to diagnose the etiology?

Recurrence of FSGS in renal allo grafts is a major cause of graft loss. In this context, we tried to diagnose and classify FSGS in renal allografts. Indications for biopsy included graft dysfunction and/or proteinuria. Three hundred and sixty-three graft biopsies were studied over a period of 2 years. We classified FSGS into recurrent FSGS, new-onset primary FSGS and FSGS secondary to chronic humoral rejection, calcineurin inhibitor toxicity, and nephron loss and hyperfiltration injury. Twenty-four cases were diagnosed as FSGS, constituting 6.6%. Secondary FSGS was the most common FSGS in grafts in our study. Incidence of recurrent FSGS may not be accurate as pretransplant biopsy is available in very few cases.

Nongassing long-lasting electro-osmotic pump with polyaniline-wrapped aminated graphene electrodes.

An efficient nongassing electro-osmotic pump (EOP) with long-lasting electrodes and exceptionally stable operation is developed by using novel flow-through polyaniline (PANI)-wrapped aminated graphene (NH2-G) electrodes. The NH2-G/PANI electrode combines the excellent oxidation/reduction capacity of PANI with the exceptional conductivity and inertness of NH2-G. The flow rate varies linearly with voltage but is highly dependent on the electrode composition. The flow rates at a potential of 5 V for pristine NH2-G and PANI electrodes are 71 and 100 µL min(-1) cm(-2), respectively, which increase substantially by the use of NH2-G/PANI electrode. It increased from 125 to 182 µL min(-1) cm(-2) as the fraction of aniline increased from 66.63 to 90.90%. The maximum flux obtained is 40 µL min(-1) V(-1) cm(-2) with NH2-G/PANI-90.9 electrodes. The assembled EOP remained exceptionally stable until the electrode columbic capacity was fully utilized. The prototype shown here delivered 8.0 µL/min at a constant applied voltage of 2 V for over 7 h of continuous operation. The best EOP produces a maximum stall pressure of 3.5 kPa at 3 V. These characteristics make it suitable for a variety of microfluidic/device applications.

Thrombotic microangiopathy in renal allografts.

Thrombotic microangiopathy (TMA) is a serious complication of renal transplantation. It is a morphological expression of various etiological factors. In a renal allograft, TMA can occur de novo or be a recurrent disease. The aim of this study was to analyze the etiological factors and observe the changing trends of TMA with respect to emerging new etiological factors. We evaluated 131 graft biopsies over a period of 2½ years (2010-2012). All the renal biopsies were formalin fixed, paraffin embedded. Twenty serial sections were studied. Stains routinely used were Hematoxylin and Eosin, Periodic Acid Schiff, Massons Trichrome and Silver Methenamine stains. C4d by immunohistochemical method was done on all graft biopsies. Incidence of TMA in our series was 9.1%. Out of the 12 cases, five were associated with calcineurin inhibitor toxicity, three were diagnosed as acute antibody-mediated rejection, and two were recurrent haemolytic uremic syndrome. One patient developed haemolytic uremic syndrome on treatment with sirolimus and one patient was cytomegalovirus positive on treatment with ganciclovir, developed haemolytic uremic syndrome during treatment course. This study describes a spectrum of etiological factors for thrombotic mciroangiopathy ranging from common cause like calcineurin inhibitor toxicity to rare cause like ganciclovir induced TMA.

Comparative bioactive studies between wild plant and callus culture of Tephrosia tinctoria pers.

Tephrosia tinctoria, a perennial under shrub of Fabaceae family, is endemic to Western Ghats. In this study, friable whitish yellow callus was developed after 45 days using Murashige and Skoog medium supplemented with 2,4-dichlorophenoxyacetic acid (2.0 mg/l) + 6-benzylaminopurine (0.5 mg/l) in various explants of T. tinctoria. The ethyl acetate extracts of leaf (LE), stem (SE), and root (RE) were compared with leaf (LCE), stem (SCE), and root (RCE) derived callus, for antioxidant and antiproliferative activities. The SE possessed the highest phenolic and flavonoid content among all the extracts tested and showed a significant antioxidant assays. The study of anticancer activity on human hepatocellular carcinoma (HepG2) cell line revealed that the callus extracts especially RCE possessed significant inhibition of cell growth (IC50 20 µg/ml) at 72 h treatment period on analysis with MTT assay. The apoptotic cell death was observed through DNA fragmentation analysis in HepG2 cells treated with the T. tinctoria extracts. The gas chromatography-mass spectrometry finger printing profile showed that more than 60 % percentage of metabolites are similar in both SE and SCE. The higher percentage area of antioxidant compound (stigmast-4-en-3-one) was observed in SE (2.01 %) and higher percentage area of anticancer compound (phenol, 2,4-bis(1,1-dimethylethyl)) in SCE (0.91 %). In addition to that, callus extracts contain squalene, which is used for target deliver and also used as anticancer drug. Thus, the present study revealed that the T. tinctoria has potent antioxidant and antiproliferative activity and the callus culture can be used for the production of the bioactive compounds due to the endemic nature of this plant.

Lumbar vertebral body bone microstructural scaling in small to medium-sized strepsirhines.

Bone mass, architecture, and tissue mineral density contribute to bone strength. As body mass (BM) increases any one or combination of these properties could change to maintain structural integrity. To better understand the structural origins of vertebral fragility and gain insight into the mechanisms that govern bone adaptation, we conducted an integrative analysis of bone mass and microarchitecture in the last lumbar vertebral body from nine strepsirhine species, ranging in size from 42 g (Microcebus rufus) to 2,440 g (Eulemur macaco). Bone mass and architecture were assessed via µCT for the whole body and spherical volumes of interest (VOI). Allometric equations were estimated and compared with predictions for geometric scaling, assuming axial compression as the dominant loading regime. Bone mass, microarchitectural, and vertebral body geometric variables predominantly scaled isometrically. Among structural variables, the degree of anisotropy (Tb.DA) was the only parameter independent of BM and other trabecular architectural variables. Tb.DA was related to positional behavior. Orthograde primates had higher average Tb.DA (1.60) and more craniocaudally oriented trabeculae while lorisines had the lowest Tb.DA (1.25), as well as variably oriented trabeculae. Finally, lorisines had the highest ratio of trabecular bone volume to cortical shell volume (∼3x) and while there appears to be flexibility in this ratio, the total bone volume (trabecular + cortical) scales isometrically (BM(1.23) , r(2) = 0.93) and appears tightly constrained. The common pattern of isometry in our measurements leaves open the question of how vertebral bodies in strepsirhine species compensate for increased BM.

Mixed-valence metal oxide nanoparticles as electrochemical half-cells: substituting the Ag/AgCl of reference electrodes by CeO(2-x) nanoparticles.

Cations of mixed valence at surfaces of metal oxide nanoparticles constitute electrochemical half-cells, with potentials intermediate between those of the dissolved cations and those in the solid. When only cations at surfaces of the particles are electrochemically active, the ratio of electrochemically active/all cations is ~0.1 for 15 nm diameter CeO(2-x) particles. CeO(2-x) nanoparticle-loaded hydrogel films on printed carbon and on sputtered gold constitute reference electrodes having a redox potential similar to that of Ag/AgCl in physiological (0.14 M) saline solutions. In vitro the characteristics of potentially subcutaneously implantable glucose monitoring sensors made with CeO(2-x) nanoparticle reference electrodes are undistinguishable from those of sensors made with Ag/AgCl reference electrodes. Cerium is 900 times more abundant than silver, and commercially produced CeO(2-x) nanoparticle solutions are available at prices well below those of the Ag/AgCl pastes used in the annual manufacture of ~10(9) reference electrodes of glucose monitoring strips for diabetes management.

Progression of hepatic aspergillosis following second renal transplantation in a patient with recurrent glomerulonephritis.

Invasive aspergillosis is a serious complication in renal transplant recipients. Hepatic involvement, although seen in liver transplant recipients, has not been reported following renal transplantation. We describe here an interesting occurrence of hepatic Aspergillus infection in a renal transplant recipient. The infection responded to anti-fungal therapy, but there was re-activation following a second renal transplant. In addition, the patient had recurrence of the underlying membrano-proliferative glomerulonephritis following both transplants. The relevant existing literature relating to these problems has been reviewed.

Efficacy of the 6-month thrice-weekly regimen in the treatment of new sputum smear-positive pulmonary tuberculosis under clinical trial conditions.

BACKGROUND: Under the Revised National Tuberculosis Control Programme of India, patients with new smear-positive pulmonary tuberculosis are treated with a thrice-weekly regimen of antitubercular drugs (2H(3)R(3)Z(3)E(3)/4H(3)R(3) [H isoniazid, R rifampicin, Z pyrazinamide and E ethambutol]) for 6 months. We conducted a retrospective analysis of the efficacy andtolerability of this regimen under clinical trial conditions in HIV-negative patients with newly diagnosed smear-positive pulmonary tuberculosis. METHODS: We retrospectively analysed the data on patients assigned to the control regimen (2H (3)R(3)Z(3)E(3)/4H(3)R(3)) in two clinical trials during 2001-06 at the National Institute for Research in Tuberculosis, Chennai, India. RESULTS: Of the 268 patients treated with this regimen, data for efficacy analysis were available for 249. At the end of treatment, of 249 patients, 238 (96%) had a favourable status. Treatment failure occurred in the remaining 11: 7 in whom the organisms were initially drug-susceptible and 4 with initial drug resistance. Of the 238 patients who had a favourable status at the end of treatment, 14 (6%) had recurrence of tuberculosis during the following 24 months. In the intention-to-treat analysis, 245 (94%) of 262 patients had a favourable status at the end of treatment. Of the 28 patients with initial drug resistance, 24 (86%) had a favourable outcome. Only 4 of these 24 patients were found to have recurrence of tuberculosis in 2 years of follow-up. Among the 221 patients initially infected with drug-susceptible organisms, drug resistance did not develop in any of the 7 patients in whom the treatment failed or the 10 who had recurrence of tuberculosis. Further, 5 of the 7 patients in whom the treatment failed continued to excrete drug-susceptible bacilli at 6 months. Adverse drug reactions were observed in 38 (14%) of the 262 patients. Only 3 (1.1%) needed a modification in the treatment. CONCLUSION: This thrice-weekly 6-month regimen of antitubercular drugs, when administered under full supervision, is associated with a high rate of favourable treatment outcomes in HIV-negative patients with newly diagnosed sputum smearpositive pulmonary tuberculosis. There are few adverse drug reactions in these patients.

Regressions for estimating muscle parameters in the thoracic and lumbar trunk for use in musculoskeletal modeling.

Musculoskeletal modeling requires information on muscle parameters such as cross-sectional area (CSA) and moment arms. A variety of previous studies have reported muscle parameters in the trunk based on in vivo imaging, but there remain gaps in the available data as well as limitations in the generalizability of such data. Specifically, available trunk muscle CSA data is very limited for older adults, lacking entirely in the thoracic region. In addition, previous studies have made measurements in groups of healthy volunteers or hospital patients who may not be representative of the population in general. Finally, such studies have not reported data for the major muscles connecting the upper limb to the thoracic trunk. In this study, muscle morphology measurements were made for major muscles present in the trunk between vertebral levels T6 and L5 using quantitative computed tomography scans from a community-based sample of 100 men and women aged 36-87. We present regression equations to predict trunk muscle CSA and position relative to the vertebral body in the transverse plane from sex, age, height and weight at vertebral levels T6 to L5. Regressions were also developed for predicting anatomical CSA and muscle moment arms, which were estimated using literature data on muscle line of action. This work thus provides a resource for estimating muscle parameters in the general population for musculoskeletal modeling of the thoraco-lumbar trunk.

A biomechanical model for estimating loads on thoracic and lumbar vertebrae.

BACKGROUND: Biomechanical models are commonly used to estimate loads on the spine. Current models have focused on understanding the etiology of low back pain and have not included thoracic vertebral levels. Using experimental data on the stiffness of the thoracic spine, ribcage, and sternum, we developed a new quasi-static stiffness-based biomechanical model to calculate loads on the thoracic and lumbar spine during bending or lifting tasks. METHODS: To assess the sensitivity of the model to our key assumptions, we determined the effect of varying ribcage and sternal stiffness, maximum muscle stress, and objective function on predicted spinal loads. We compared estimates of spinal loading obtained with our model to previously reported in vivo intradiscal pressures and muscle activation patterns. FINDINGS: Inclusion of the ribs and sternum caused an average decrease in vertebral compressive force of 33% for forward flexion and 18% in a lateral moment task. The impact of maximum muscle stress on vertebral force was limited to a narrow range of values. Compressive forces predicted by our model were strongly correlated to in vivo intradiscal pressure measurements in the thoracic (r=0.95) and lumbar (r=1) spine. Predicted trunk muscle activity was also strongly correlated (r=0.95) with previously published EMG data from the lumbar spine. INTERPRETATION: The consistency and accuracy of the model predictions appear to be sufficient to justify the use of this model for investigating the relationships between applied loads and injury to the thoracic spine during quasi-static loading activities.