Sural Artery as a Recipient Vessel for Free Flaps

Introduction The axial vessels like the anterior and posterior tibial emerge as the first choice of recipient vessels, in free flaps for lower limb trauma. When the defects are located more proximally in the leg, the deeper course of the axial vessels makes the dissection more tedious. Alternative vessels like the descending genicular, medial genicular, and distal end of the descending branch of the lateral circumflex femoral can be used for an end-to-end anastomosis, well away from the zone of trauma.

The objective of this study was to define the indications and technique of the use of the sural vessels as the recipient pedicle for proximal and middle third leg defects.

Patients and Methods For the period 2006 to 2022, 18 leg defects following road traffic accidents were covered with latissimus dorsi muscle flap using sural vessels as the recipient pedicle.

Results Among 18 patients, 8 patients had defect in proximal third, 8 had a combined defect in proximal and middle third leg, and 2 had defect in middle third leg. Two patients developed arterial thrombosis and one patient had venous thrombosis for which re-exploration was performed. Two flaps were lost and sixteen had successful wound coverage.

Conclusion The sural vessels as recipient pedicle are easier to access and can be considered as a reliable option for free flaps in limb defects of proximal and middle third leg. Using the submuscular part of the vessel ensures a better distal reach of the flap.

Is Single-stage Microvascular Reconstruction for Facial Mucormycosis Safe?

Introduction This is a retrospective therapeutic series of eight cases of facial mucormycosis treated over a 15-year period to determine the safety of simultaneous debridement and free-flap reconstruction in facial mucormycosis.

Methods Surgical debridement was done for three cases that presented acutely with systemic manifestations (group 1) and five cases that presented in the subacute phase without systemic manifestations (group 2). The debridement involved total maxillectomy with orbital exenteration in three cases, total maxillectomy with orbital preservation in two, and subtotal maxillectomy in three cases. A total of seven out of eight patients underwent reconstruction with free flap for defect closure; in one patient, only primary closure of mucosa was done.

Results The mean follow-up was 20.5 months. Two patients with acute disease, where reconstruction was done, died in the postop period (on the 27th and 6th day post reconstruction, respectively) due to continuing infection and septic shock. One of the three (group 1), who presented acutely and underwent debridement alone, survived. Four of five patients in group 2 underwent successful free-flap reconstruction. The patient with free-flap loss was salvaged with an extracorporeal radial forearm flap. All except one patient had a soft-tissue free-flap reconstruction. Three of the six living patients reported for secondary surgery. The inability to achieve clear nonnecrotic surgical margins due to extensive disease was the reason for mortality in two patients in group 1. There was no mortality in any of the group 2 patients, even when debridement and free-flap coverage was done simultaneously.

Conclusion Simultaneous debridement and free flap can be successfully implemented in select cases of facial mucormycosis

Anterolateral Thigh Skin and Fascia in Facial Skin Defects with Trismus: Two Problems, One Solution

A case series of five patients with skin loss in the lateral face with trismus that followed delayed presentation following trauma, necrotizing infection, and radiation fibrosis was treated with coronoidectomy and condylar excision to effect adequate mouth opening; the anterolateral thigh flap was used for cover and the fascia was used as an interposition graft to prevent recurrence. Two patients with more than 9 years of follow-up had an average of 40 mm interincisal opening.

Viability of power distribution in India - Challenges and Way Forward

Energy is a key component for economic growth as well as for human development. India is the third-ranking electricity generator in the world but ranks 106th in terms of per capita consumption. Specifically, the distribution of power is the most important link in the value chain of the power sector since it is the cash register for the entire sector. In India, electricity is a concurrent subject shared between the Central and State Governments. While the generation of power has been deregulated since 2003, the supply of power to the consumers is generally carried out by Government-owned power Distribution Companies (DISCOMs). In this paper, the authors analyze the financial distress of DISCOMs in India, and explain how the supply-demand mismatch due to over-ambitious demand projections, the fixed and energy charges of thermal power plants, and the excess procurement of "must-run" renewable sources together contribute to the high cost of power procurement that drives the financial stress faced by DISCOMs. The authors support their assertion with a study of nine DISCOMs supplying electricity to 155 million people in three States and propose policy recommendations for a turnaround of such DISCOMs which can be rolled out with suitable modifications across India.

Temporal self-similarity of quantum dynamical maps as a concept of memorylessness

The problem of defining quantum non-Markovianity has proven elusive, with various in-equivalent criteria put forth to address it. The concept of CP-indivisibility and the hierarchy of stronger divisibility criteria going up to P-indivisibility, capture a fundamental aspect of memory in quantum non-Markovianity. In practice, however, there can be a memory-like influence associated with divisible channels in the form of weakening, if not reversing, the effects of decoherence. Arguably, such a facet of memory relates to CP-indivisibility as quantum discord relates to entanglement. We concretize this weaker notion of non-Markovianity by identifying it with deviation from "temporal self-similarity", the property of a system dynamics whereby the propagator between two intermediate states is independent of the initial time [Formula: see text]. We illustrate this idea through examples, and propose a geometric quantification of temporal self-similarity, and show how our approach complements the divisibility-based criterion of quantum non-Markovianity.

Noisy three-player dilemma game: robustness of the quantum advantage

Games involving quantum strategies often yield higher payoff. Here, we study a practical realization of the three-player dilemma game using the superconductivity-based quantum processors provided by IBM Q Experience. We analyze the persistence of the quantum advantage under corruption of the input states and how this depends on parameters of the payoff table. Specifically, experimental fidelity and error are observed not to be properly anti-correlated; i.e., there are instances where a class of experiments with higher fidelity yields a greater error in the payoff. Further, we find that the classical strategy will always outperform the quantum strategy if corruption is higher than 50%.

Anterolateral Thigh Flap-the Optimal Flap in Coverage of Severe Elbow Injuries

Introduction Traditionally, the latissimus dorsi muscle with or without skin paddle has been the flap of choice for coverage of elbow defects. The ALT flap has found application in elective upper limb defects on account of it's ability to be tailor made for individual defects. Our series of 10 cases shows the advantages of using this flap for acute trauma defects. Materials and Methods Consecutive 10 cases of severe elbow injuries, involving varying amounts of the lower arm and proximal forearm underwent debridement followed by coverage using the free anterolateral thigh flap. Nine of 10 arterial anastomosis were done end to side to the brachial artery and venous anastomosis to the veins accompanying the artery. Seven of these patients had long bone fractures and elbow dislocations, stabilised using external fixator. Four patients needed primary muscle or tendon repair and nerve repair or graft. Results There was 1 total flap loss, intraoperatively where a TFL flap had been used in a 71 year-old patient. Nine of 10 had successful wound coverage. Using Jupiter criteria, 2 had excellent, 3 had good, 3 had fair, and 1 had poor outcome. Conclusion This consecutive series of moderate and severe elbow injuries demonstrates that the ALT flap should be considered as the flap of first choice, specifically when there is a need.

Free Tissue Transfer in Pediatric Lower Limb Trauma

Free tissue transfer has become the standard in wound coverage and further refinements have given us newer flap donor sites or modifications of existing flaps to decrease morbidity; smaller vessels are being anastomosed, a direct spin-off following successful distal replantations. Younger children are presenting with traumatic defects similar to adults. Although there were apprehensions of free tissue transfer in children occasioned by smaller vessels, duration of procedure and concerns of growth following flap harvest, reports of small and large series have appeared in the literature with similar success. Pediatric-free tissue transfer is now an established entity. This article seeks to arrive at a consensus based on a review of the existing literature on free flaps for skin and soft-tissue coverage of lower limb trauma in children.

Brachioradialis to flexor digitorum profundus tendon transfer to restore finger flexion

Introduction:

The main deformity following an adult lower brachial plexus injury is the loss of finger flexion. Distal nerve transfers have been used to restore finger and thumb flexion followed by tendon transfers for intrinsic replacement for opening of the fingers. When patients present beyond 6 months, only tendon transfers are applicable. Since the brachioradialis (BR) is always spared in such injuries, it is the ideal muscle to provide finger flexion. Wrist extensor power may not be normal for the use of the radial wrist extensor to serve as donor. BR to FDP transfer provides reasonable flexion range and an acceptable hand function to permit activities of daily living, when associated with ancillary procedures like opponensplasty, PIPJ arthrodesis.

Materials and Methods:

Eleven patients underwent a BR to FDP tendon transfer between January 2013 and January 2017 of which eight patients came for follow-up.

Results:

Four of the eight patients got a functionally useful hand to carry out activities of daily living with hook grip, span grasp, key pinch, chuck grip and pulp pinch. These patients also underwent simultaneous or secondary ancillary procedures. Four of the patients need secondary procedures to further improve functionality of the hand inspite of having a flexion range.

Conclusion:

The BR is an effective donor in providing adequate range and power of finger flexion in lower plexus injuries.

Reconstruction in head-and-neck cancers - analysis of the learning curve

BACKGROUND

Oral cancers are some of the most common cancers in India. Most patients present with locally advanced disease requiring extensive resection resulting in large defects. Reconstruction of these defects plays a major role in restoring form and function to these patients, as well as enabling the delivery of adjuvant therapy on time.

AIM OF THE STUDY

The aim of this study was to analyze the learning curve involved in microvascular surgery.

MATERIALS AND METHODS

A retrospective analysis of the case records of all patients of oral cancers, who underwent resection and reconstruction between January 2008 and December 2012 at our institute, was done. Demographic, clinical, and pathological data were collected and analyzed. Statistical analysis was done using the SPSS software.

RESULTS

The operative time and the postoperative ventilation (7.8 h and 3.7 days, respectively) were significantly higher than those for pedicled flaps (3.6 h and 1.4 days, respectively). Both these variables reached statistical significance with P < 0.05 and < 0.04. The hospital stay was also statistically significantly longer for patients who underwent free-flap reconstruction (17.9 days vs. 7.9 days; P < 0.05). The number of reexplorations were higher in the free-flap group (31), when compared to the pedicled flap group (9). However, partial flap loss was higher in the pedicled flap subset when compared to the free-flap group. The complications significantly dropped after the performance of 30-40 free flaps.

CONCLUSION

There is a steep learning curve in microvascular surgery, but the cosmetic and functional outcomes outweigh the complications.

Triceps to biceps transfer for restoration of elbow flexion following upper brachial plexus injury

INTRODUCTION

Upper brachial plexus injury in adults causes loss of elbow fl exion; when the primary nerve surgery has failed or the patient seeks treatment after 12 months of injury and pedicled muscle transfers are required. Most commonly, the latissimus dorsi or the Steindler flexorplasty is used.

MATERIAL AND METHODS

We have transferred one of the heads of triceps muscle to restore the elbow flexion in such cases. In addition to return of elbow flexion, extension of elbow following surgery is retained. Ten patients suffering from upper brachial plexus injuries underwent transfer of one head of triceps to biceps tendon between December 2011 and August 2015.

RESULTS

The recovery of elbow flexion was Grade 5 in 1, Grade 4 in 4 and Grade 3 in 2; only three of the ten patients had no functionally useful elbow flexion. Seven of the ten patients had an adequate elbow extension following the procedure.

A quantum-information theoretic analysis of three-flavor neutrino oscillations: Quantum entanglement, nonlocal and nonclassical features of neutrinos

Correlations exhibited by neutrino oscillations are studied via quantum-information theoretic quantities. We show that the strongest type of entanglement, genuine multipartite entanglement, is persistent in the flavor changing states. We prove the existence of Bell-type nonlocal features, in both its absolute and genuine avatars. Finally, we show that a measure of nonclassicality, dissension, which is a generalization of quantum discord to the tripartite case, is nonzero for almost the entire range of time in the evolution of an initial electron-neutrino. Via these quantum-information theoretic quantities, capturing different aspects of quantum correlations, we elucidate the differences between the flavor types, shedding light on the quantum-information theoretic aspects of the weak force.

To evaluate the feasibility of neurotisation of facial nerve branches with ipsilateral masseteric nerve: an anatomic study

CONTEXT

Facial palsy is a common problem encountered in clinical practice. These patients suffer serious functional, cosmetic & psychological problems with impaired ability to communicate. Functional problems around the eye are usually a first priority for the patient with facial palsy.The nerve to masseter as a direct nerve transfer to the zygomatic branch of facial nerve to reinnervate viable facial muscles within a year after the onset of paralysis has been scarcely reported. This study was contemplated to evaluate the feasibility of neurotisation of zygomatic branch of facial nerve with masseteric nerve branch of the trigeminal nerve Objectives: Establishing the anatomic relationship of masseteric nerve to masseteric muscle, determining feasibility of neurotisation of zygomatic branch of facial nerve using the nerve to the masseter and establishing fascicular correlation of the donor and the recipient nerves.

MATERIALS AND METHODS

Ninteen hemi-faces in ten fresh cadavers (6 Male and 4 Female)were dissected in a forensic morgue and access was by a standard preauricular incision and anterior skin flap is elevated in a subcutaneous plane. Facial nerve and its two main divisions are dissected in its full A*/extratemporal course. Zygomatic branch dissected upto zygomatic arch and the nerve to the masseter is identified within the masseter muscle, dissected proximodistally to isolate it. Feasibility of transfer of this masseteric nerve to the zygomatic branch without using nerve graft is determined. At the completion of dissection, the ends of both nerves are sent for HPE analysis to determine fascicular anatomy and count.

RESULTS

The dissection of massteric nerve was done taking into consideration of 3 axes, that is anteroposterior (x), vertical (y) axes and mediolateral(z) for locating the nerve and for standardization of the dissection. The nerve was cut and stored in glutaraldehyde solution and subjected to histopathologic examination after fixing and staining with Haematoxilin-eosin stain. Donor masseter neve has 7-10 fascicles. Recipient zygomatic branch has 2-3 fascicles. And the buccal branch has 5-6 fascicles.

CONCLUSION

The use of the nerve to masseter offers a simpler ipsilateral alternative for neurotisation of the facial nerve branches in patients who have an early facial nerve paralysis.

Urinary fluoride as a monitoring tool for assessing successful intervention in the provision of safe drinking water supply in five fluoride-affected villages in Dhar district, Madhya Pradesh, India

Endemic fluorosis was detected in 31 villages in the Dhar district of Madhya Pradesh, Central India. Out of the 109 drinking water sources that were analyzed, about 67 % were found to contain high concentration of fluoride above the permissible level of 1.0 mg/l. Dental fluorosis among the primary school children in the age between 8 and 15 served as primary indicator for fluoride intoxication among the children. Urinary fluoride levels among the adults were found to be correlated with drinking water fluoride in 10 villages affected by fluoride. Intervention in the form of alternate safe water supply in five villages showed significant reduction in the urinary fluoride concentration when compared to the control village. Urinary fluoride serves as an excellent marker for assessing the effectiveness of intervention program in the fluoride-affected villages.

Orbital dermoid mimicking a monocular elevation deficiency

Dermoid cysts are choristomas (a mass of histologically normal tissue in an abnormal location), which originate from aberrant primordial tissue and are often evident soon after birth. It may occur anywhere in the body. Dermoid cysts account for about 3-9% of all orbital masses and 0.04-0.6% of primary orbital tumors. The frequent site of origin is the superotemporal quadrant of orbit. Depending on the location, size, and associated abnormalities of the cyst, the patient may have proptosis, diplopia, and restriction of eye movements. Monocular elevation deficiency (MED) is the inability to elevate one eye in abduction, adduction, or from primary position. We report this case of orbital dermoid in an adult female presenting as a monocular elevation deficiency with unilateral ptosis of right eye which was investigated and managed with good results.

Osteoporosis in people with intellectual disabilities: a review and a brief study of risk factors for osteoporosis in a community sample of people with intellectual disabilities

BACKGROUND

The population of people with intellectual disabilities (ID) is increasing and their health needs impact on primary and secondary healthcare specialities. One important aspect of their physical health is bone health as people with ID have increased risk factors associated with osteoporosis. It has been identified that this population has an increased prevalence of low bone mineral density (BMD), osteoporosis and osteopenia. The main contributory factors for low BMD are age, use of antiepileptics, immobility and diagnosis of Down's syndrome.

METHODS

A literature search of electronic databases was undertaken. Studies that included people with ID were reviewed for the prevalence of osteoporosis and osteopenia. A cross-sectional survey was conducted in a community sample (n = 149) to screen for risk factors for osteoporosis.

RESULTS

The majority of studies identified increased prevalence of osteoporosis and osteopenia with associated low BMD. In most studies individuals with ID presented with more than two risk factors. In our survey, we identified an increased prevalence of risk factors associated with osteoporosis, namely use of antiepileptics (64%), immobility (23%), history of falls (20%) and fractures (11%). We found that 54% of our sample fulfilled the criteria for screening. Of those who went on to have scans, 55% had osteoporosis and 33% had osteopenia.

CONCLUSION

We conclude that we should be screening for the risk factors associated with low BMD in adults with ID. If these are present further investigations should take place and those found to have osteoporosis and osteopenia should have treatment at an early stage to prevent morbidity and improve their quality of life.

Efficacy of palatal block for analgesia following palatoplasty in children with cleft palate

BACKGROUND

This prospective randomized controlled study was undertaken to evaluate the efficacy of palatal block i.e. blocking of naso palatine, greater and also lesser palatine nerves in children with cleft palate undergoing palatoplasty by evaluating its effects on intraoperative anesthetic requirement, postoperative analgesia and parental satisfaction.

METHODS

Forty-five pediatric patients aged below five undergoing cleft palate repair were randomly allocated to three groups of 15 each. After tracheal intubation, Group NB received no block for control, group S received 0.5 ml of normal saline and group B received 0.5 ml of 0.25% bupivacaine for palatal block. Postoperative pain score, the time to first demand of analgesia and number of rescue analgesic demands were noted. Finally, the parental satisfaction was graded.

RESULTS

The block had no anesthetic sparing effect. The mean pain scores were significantly lower in patients who received block than in the group NB. The mean area under curve for FLACC score in group NB was 29 with 95% CI of 25-32, group S was 15 with 95% CI of 8.9-22.3 and in group B, it was 10 with 95% CI of 6-14. The time to first demand of analgesia was 6 [4.5-6] h in group NB, 18 [6-18] h in group S and 18 [18-18] h in group B (P-0.000). The number of demands of rescue analgesia was significantly less in group B 0 [0-0.25], 0 [0-2] in S group compared to group NB 3 [3-3] (P-0.000). The parental satisfaction was good in patients who received block and poor in group NB.

CONCLUSION

Palatal block is technically simple, safe and effectively provides postoperative analgesia with good parental satisfaction. Injection of saline also produced palatal nerve block; however, the effect was not consistent.

Constraints on anaerobic respiration in the hyperthermophilic Archaea Pyrobaculum islandicum and Pyrobaculum aerophilum

Pyrobaculum islandicum uses iron, thiosulfate, and elemental sulfur for anaerobic respiration, while Pyrobaculum aerophilum uses iron and nitrate; however, the constraints on these processes and their physiological mechanisms for iron and sulfur reduction are not well understood. Growth rates on sulfur compounds are highest at pH 5 to 6 and highly reduced (<-420-mV) conditions, while growth rates on nitrate and iron are highest at pH 7 to 9 and more-oxidized (>-210-mV) conditions. Growth on iron expands the known pH range of growth for both organisms. P. islandicum differs from P. aerophilum in that it requires direct contact with insoluble iron oxide for growth, it did not produce any extracellular compounds when grown on insoluble iron, and it lacked 2,6-anthrahydroquinone disulfonate oxidase activity. Furthermore, iron reduction in P. islandicum appears to be completely independent of c-type cytochromes. Like that in P. aerophilum, NADH-dependent ferric reductase activity in P. islandicum increased significantly in iron-grown cultures relative to that in non-iron-grown cultures. Proteomic analyses showed that there were significant increases in the amounts of a putative membrane-bound thiosulfate reductase in P. islandicum cultures grown on thiosulfate relative to those in cultures grown on iron and elemental sulfur. This is the first evidence of this enzyme being used in either a hyperthermophile or an archaeon. Pyrobaculum arsenaticum and Pyrobaculum calidifontis also grew on Fe(III) citrate and insoluble iron oxide, but only P. arsenaticum could grow on insoluble iron without direct contact.

Improved sequencing of oxidized cysteine and methionine containing peptides using electron transfer dissociation

Oxidative modifications to the side chains of sulfur-containing amino acids often limit the number of product ions formed during collision-induced dissociation (CID) and thus make it difficult to obtain sequence information for oxidized peptides. In this work, we demonstrate that electron-transfer dissociation (ETD) can be used to improve the sequence information obtained from peptides with oxidized cysteine and methionine residues. In contrast to CID, ETD is found to be much less sensitive to the side-chain chemistry, enabling extensive sequence information to be obtained in cases where CID fails to provide this information. These results indicate that ETD is a valuable technique for studying oxidatively modified peptides and proteins. In addition, we report a unique and very abundant product ion that is formed in the CID spectra of peptides having N-terminal cysteine sulfinic acid residues. The mechanism for this unique dissociation pathway involves a six-membered cyclic intermediate and leads to the facile loss of NH(3) and SO(2), which corresponds to a mass loss of 81 Da. While the facile nature of this dissociation pathway limits the sequence information present in CID spectra of peptides with N-terminal cysteine sulfinic acid residues, extensive sequence information for these peptides can be obtained with ETD.

The effect of histidine oxidation on the dissociation patterns of peptide ions

Oxidative modifications to amino acid side chains can change the dissociation pathways of peptide ions, although these variations are most commonly observed when cysteine and methionine residues are oxidized. In this work we describe the very noticeable effect that oxidation of histidine residues can have on the dissociation patterns of peptide ions containing this residue. A common product ion spectral feature of doubly charged tryptic peptides is enhanced cleavage at the C-terminal side of histidine residues. This preferential cleavage arises as a result of the unique acid/base character of the imidazole side chain that initiates cleavage of a proximal peptide bond for ions in which the number of protons does not exceed the number of basic residues. We demonstrate here that this enhanced cleavage is eliminated when histidine is oxidized to 2-oxo-histidine because the proton affinity and nucleophilicity of the imidazole side chain are lowered. Furthermore, we find that oxidation of histidine to 2-oxo-histidine can cause the misassignment of oxidized residues when more than one oxidized isomer is simultaneously subjected to tandem mass spectrometry (MS/MS). These spectral misinterpretations can usually be avoided by using multiple stages of MS/MS (MS(n)) or by specially optimized liquid chromatographic separation conditions. When these approaches are not accessible or do not work, N-terminal derivatization with sulfobenzoic acid avoids the problem of mistakenly assigning oxidized residues.

A simple classification for standardisation of nomenclature in free flap outcome

The numbers of free flap donor site as well as their indications are constantly increasing. Despite increasing popularity of microvascular reconstructive procedures, literature lacks clear and objective outcome criteria. This paper reports on a simple outcome classification that has become a routine part of the unit's large workload of microvascular outcome recording. The classification was formed through a retrospective analysis of 241 consecutive cases from 2000 to 2001 and is a five graded numerical classification. Grade 1 equates to total success without co-morbidity and grade 5 to a major complication such as amputation, etc., whatever the status of the flap itself. From 2002 to 2005 the classification was prospectively used on 527 consecutive cases with ease of integration into routine clinical practice. The Classification would enable a more objective record keeping thus analysis of the outcome. It would allow a more realistic comparison of different techniques or donor types as well set a benchmarking level for further improvement of the results.

Estimation of false discovery rates for wavelet-denoised statistical parametric maps

Correction for multiple comparisons in neuroimaging data is an important area of research. Recently, wavelet-based methods have gained popularity and have been reported to achieve better sensitivity compared to spatial domain methods. However, these techniques produce smoothed statistical maps which are difficult to interpret. The generated maps have to be thresholded again in the spatial domain to delineate active from inactive regions. The selection of a proper threshold satisfying the required error rate control is not straightforward. In this paper, a framework is proposed for thresholding wavelet-denoised maps in which a rejection region is fixed, and the achieved false discovery rate (FDR) is estimated. This approach provides a meaningful strategy to choose thresholds for wavelet-denoised statistical parametric maps (SPMs). Two FDR estimation algorithms were used to assess the achieved error rate control when thresholding wavelet filtered SPMs at various rejection regions. Their performance was evaluated using both simulated and resting fMRI data. The proposed framework was also applied on in vivo data.

Wavelet-based estimation of hemodynamic response function from fMRI data

We present a new algorithm to estimate hemodynamic response function (HRF) and drift components of fMRI data in wavelet domain. The HRF is modeled by both parametric and nonparametric models. The functional Magnetic resonance Image (fMRI) noise is modeled as a fractional brownian motion (fBm). The HRF parameters are estimated in wavelet domain by exploiting the property that wavelet transforms with a sufficient number of vanishing moments decorrelates a fBm process. Using this property, the noise covariance matrix in wavelet domain can be assumed to be diagonal whose entries are estimated using the sample variance estimator at each scale. We study the influence of the sampling rate of fMRI time series and shape assumption of HRF on the estimation performance. Results are presented by adding synthetic HRFs on simulated and null fMRI data. We also compare these methods with an existing method,(1) where correlated fMRI noise is modeled by a second order polynomial functions.

Polarization-rich continuous wave direct imaging: modeling and visualization

We report a study and comparison of continuous-wave, optical polarization difference imaging (PDI) and polarization modulation imaging (PMI) for imaging through scattering media. The problem is cast in the framework of a theoretical estimation, and the comparison is based on three visualization parameters, namely, the magnitude, the degree, and the orientation of the polarization. We show that PDI is superior in estimating the first two parameters in active imaging under specific conditions, while the PMI is suitable for passive imaging and is the only way to estimate polarization orientation. We also propose new schemes for rendering polarization information as a color image and for applying the newly introduced polarization-orientation imaging for segmentation. Simulation and experimental results verify the theoretical conclusions.

Electrospray tandem mass spectrometry of alkali-cationized BocN-carbo-alpha,beta- and -beta,alpha-peptides: Differentiation of positional isomers

Dissociation pathways of a series of alkali-cationized hybrid peptides, viz., Boc-alpha,beta- and -beta,alpha-carbopeptides, synthesized from C-linked carbo-beta3-amino acids [Caa (S)] and alpha-alanine (L-Ala), have been investigated by electrospray ionization tandem mass spectrometry. The positional isomers (six pairs) of the cationized alpha,beta- and beta,alpha-peptides can be differentiated by the collision-induced dissociation (CID) spectra of their [M + Cat-Boc + H]+ ions which give characteristic series of alkali-cationized C- (x(n)+, y(n)+, z(n)+) and N-terminal (a(n)+, b(n)+, c(n)+) ions. Another noteworthy difference is cationized beta,alpha-peptides eliminate a molecule of ammonia whereas this pathway is absent for alpha,beta-peptides. This is useful for identifying the presence of a beta-amino acid at the N-terminus. The CID spectra of [M + Cat-Boc + H]+ ions of these peptide acids show abundant rearrangement [b(n) + 17 + Cat]+ (n = 1 to n-1) ions which is diagnostic for distinguishing between alpha- and beta-amino acid at the C-terminus. MS(n) experiments of [b(n) + Li-H]+ ions from these hybrid peptides showed the loss of CO and 72 u giving rise to [a(n) + Li-H]+ and cationized nitrile product ions which render support to earlier proposals that b(n)+ or [b(n) + Cat-H]+ ions have protonated or cationized oxazolinone structures, respectively.

Differentiation of Boc- alpha,beta- and beta,alpha-peptides and a pair of diastereomeric beta,alpha-dipeptides by positive and negative ion electrospray tandem mass spectrometry (ESI-MS/MS)

Positive and negative ion electrospray ionization (ESI) tandem mass spectral study of a new series of hybrid peptides, viz, BocN-alpha,beta-peptides and BocN-beta,alpha-peptides, synthesized from C-linked carbo-beta3-amino acids [Caa (S)] and L-Ala has been carried out. The alpha,beta-peptides have been differentiated from beta,alpha-peptides by the collision-induced dissociation (CID) of [M + H]+ and [M - H]- ions in positive and negative ion ESI-MS respectively. The fragment ion [M + H - C(CH3)3 + H]+ formed from [M + H]+ ions by the loss of 2-methyl-prop-2-ene in alpha,beta-peptides with L-Ala at the N-terminus is insignificant or totally absent for beta,alpha-peptides which have the Caa (S) at N-terminus. The fragment ion [M - H-C(CH3)3OH - HNCO]- formed from [M - H]- of beta,alpha-peptide acids is totally absent for alpha,beta-peptide acids. This has been attributed to the absence of the beta-methylene group in alpha,beta-peptides, and the participation of the beta-methylene group in the loss of HNCO in beta,alpha-peptide acids is confirmed by the deuteration experiments. The CID of [M + H-Boc + H]+ ions of these peptides also produce characteristic fragmentation. In the CID spectra of alpha,beta-peptides, the b(n)+ ions and the resulting y(n)+ ions occur at a mass difference of 243 and 71 Da corresponding to the successive losses of Caa and L-Ala, whereas a mass difference of 71 and 243 Da is observed for beta,alpha-peptides. In contrast to the CID of protonated peptides, the CID of [M - H]- ions of the alpha,beta- and beta,alpha-peptide acids do not give b(n)- ions and show abundant z(n) (-) ions. Further, a pair of diastereomeric dipeptide esters and acids have been distinguished by the CID of [M + H]+ ions. The loss of 2-methyl-prop-2-ene is more pronounced for Boc-NH-Caa(R)-D-Ala-OCH3 (21) and Boc-NH-Caa(R)-D-Ala-OH (23) with Caa (R) at the N-terminus, whereas it is totally absent for Boc-NH-Caa (S)-D-Ala-OCH3 (22) and Boc-NH-Caa(S)-D-Ala-OH (24) peptides, which have Caa (S) at the N-terminus. Thus, on the basis of our previous and present studies, we propose that the CID of [M + H]+ ions provides a simple and useful method for distinguishing the configuration of Caa (S or R) at the N-terminus of BocN-carbo beta,alpha- and beta,beta-dipeptides.

Contextual encoding in uniform and adaptive mesh-based lossless compression of MR images

We propose and evaluate a number of novel improvements to the mesh-based coding scheme for 3-D brain magnetic resonance images. This includes: 1) elimination of the clinically irrelevant background leading to meshing of only the brain part of the image; 2) content-based (adaptive) mesh generation using spatial edges and optical flow between two consecutive slices; 3) a simple solution for the aperture problem at the edges, where an accurate estimation of motion vectors is not possible; and 4) context-based entropy coding of the residues after motion compensation using affine transformations. We address only lossless coding of the images, and compare the performance of uniform and adaptive mesh-based schemes. The bit rates achieved (about 2 bits per voxel) by these schemes are comparable to those of the state-of-the-art three-dimensional (3-D) wavelet-based schemes. The mesh-based schemes have been shown to be effective for the compression of 3-D brain computed tomography data also. Adaptive mesh-based schemes perform marginally better than the uniform mesh-based methods, at the expense of increased complexity.

Mass spectral study of Boc-carbo-beta3-peptides: differentiation of two pairs of positional and diastereomeric isomers

A mass spectral study of a series of new Boc-C-linked carbo-beta(3)-peptides prepared from C-linked carbo-beta(3)-amino acids (Caa) was carried out using liquid secondary ion mass spectrometry (LSIMS), electrospray ionization (ESI) and tandem mass spectrometry. Using the nomenclature of Roepstorff and Fohlman, the positive ion high- and low energy collision-induced dissociation (CID) of [M + H - Boc + H](+) ions of the peptides produce both N- and C-terminus ions, y(n) (+) and b(n) (+) ions, with high abundance and other ions of low abundance. Further, characteristic fragment ions of carbohydrate moiety are observed. In contrast to the CID of protonated peptide acids, the CID of [M - H](-) ions of the beta(3)-peptide acids do not give b(n)(-) ions and show abundant z(n)(-) and c(n) (-) ions which are insignificant in the former. Two pairs of positionally isomeric Boc-carbo-beta(3)-dipeptides were differentiated by the CID of [M + H](+) ions in LSIMS and ESIMS. The fragment ion [M + H - C(CH(3))(3) + H](+) formed from [M + H](+) by the loss of 2-methylprop-2-ene is relatively more abundant in the dipeptide Boc-NH-beta-hGly-Caa(S)-OCH(3) (14) containing the sugar moiety at the C-terminus whereas it is insignificant in Boc-NH-Caa(S)-beta-hGly-OCH(3) (13), which has the sugar moiety at the N-terminus. Similarly, two pairs of diastereomeric dipeptides were distinguished by the high- and low-energy CID of [M + H](+) ions. The loss of 2-methylprop-2-ene is more pronounced for Boc-NH-Caa(R)-beta-hGly-OCH(3) (17) and Boc-NH-Caa(R)-Caa(S)-OCH(3) (18) isomers whereas it is insignificant for Boc-NH-Caa(S)-beta-hGly-OCH(3) (13) and Boc-NH-Caa(S)-Caa(S)-OCH(3) (2) isomers. This was attributed to a favorable configuration of the carbohydrate moiety favoring the 'H' migration involved in the loss of 2-methylprop-2-ene from the [M + H](+) ions of isomers 17 and 18 compared with the unfavorable configuration of the carbohydrate moiety in isomers 13 and 2.

Prevalence of Giardiasis due to wastewater reuse for agriculture in the suburbs of Asmara City, Eritrea

A study was undertaken to assess the health impact of utilization of the raw domestic sewage for vegetable cultivation in the suburbs of the capital city of Asmara, Eritrea. Standard techniques were adopted for the analysis of the samples. Results showed heavy contamination of vegetables by faecal coliforms as well as with Giardia cysts. Stool samples of 75 farmers who were occupationally exposed revealed that 45% of them were harbouring giardia cysts. The dietary intake of raw salads (lettuce, cabbage) grown on the raw sewage appear to be a causative factor of Giardiasis in the farming community as well as in the town of Tsadachristian located on the suburbs of the capital city of Asmara. The hospital data of the affected town is compared with other towns of Eritrea. The result indicates agriculture reuse of untreated wastewater is a major cause for the increase in Giardasis.

Mass spectral study of alkali-cationized Boc-carbo-beta3-peptides by electrospray tandem mass spectrometry

Electrospray tandem mass spectrometry was used to study the dissociation reactions of [M+Cat]+ (Cat = Na+ and Li+) of Boc-carbo-beta3-peptides. The collision-induced dissociation (CID) spectra of [M+Cat-Boc]+ of these peptides are found to be significantly different from those of [M+H-Boc]+ ions. The spectra are more informative and display both C- and N-terminus metallated ions in addition to characteristic fragment ions of the carbohydrate moiety. Based on the fragmentations observed in the CID spectra of the [M+Cat-Boc]+ ions, it is suggested that the dissociation involves complexes in which the metal ion is coordinated in a multidentate arrangement involving the carbonyl oxygen atoms. The CID spectra of [M+Cat-Boc]+ ions of the peptide acids show an abundant N-terminal rearrangement ion [b(n)+17+Cat]+ which is absent for esters. Further, two pairs of positionally isomeric Boc-carbo-beta3-peptide acids, Boc-NH-Caa(S)-beta-hGly-OH (11) and Boc-NH-beta-hGly-Caa(S)-OH (12), and [Boc-NH-Caa(S)-beta-hGly-Caa(S)-beta-hGly-OH] (13) and [Boc-NH-beta-hGly-Caa(S)-beta-hGly-Caa(S)-OH] (14), were differentiated by the CID of [M+Cat-Boc]+ ions. The CID spectra of compounds 11 and 13 are significantly different from those of 12 and 14, respectively. The abundance of [b(n)+17+Cat]+ ions is higher for peptide acids 12 and 14 with a sugar group at the C-terminus when compared to 11 and 13 which contain a sugar moiety at the N-terminus. The observed differences between the CID spectra of these isomeric peptides are attributed to the difference in the preferential site of metal ion binding and also on the structure of the cyclic intermediate involved in the formation of the rearrangement ion.

Fluoride in groundwater in selected villages in Eritrea (North East Africa)

A study was undertaken to estimate fluoride content in the groundwater in certain parts of rural Eritrea. North-East Africa, along the River Anseba. Standard procedure was adopted for fluoride detection. Results indicate elevated concentration of fluoride in groundwater. The highest concentration was found to be 3.73 mg L(-1), well above the safety level for consumption. Geological basis for the high concentration of high fluoride has been established; it is presumed to be the pegmatite intrusion hosted by a granitic batholith. Extensive dental fluorosis has been observed in the population exposed to drinking water of high fluoride content.

Generation and characterization of ionic and neutral P(OH)2+/* in the gas phase by tandem mass spectrometry and computational chemistry

The bicoordinated dihydroxyphosphenium ion P(OH)2+ (1+) was generated specifically by charge-exchange dissociative ionization of triethylphosphite and its connectivity was confirmed by collision induced dissociation and neutralization-reionization mass spectra. The major dissociation of 1+ forming PO+ ions at m/z 47 involved another isomer, O=P-OH2+ (2+), for which the optimized geometry showed a long P-OH2 bond. Dissociative 70-eV electron ionization of diethyl phosphite produced mostly 1+ together with a less stable isomer, HP(O)OH+ (3+). Ion 2+ is possibly co-formed with 1+ upon dissociative 70-eV electron ionization of methylphosphonic acid. Neutralization-reionization of 1+ confirmed that P(OH)2* (1) was a stable species. Dissociations of neutral 1, as identified by variable-time measurements, involved rate-determining isomerization to 2 followed by fast loss of water. A competitive loss of H occurs from long-lived excited states of 1 produced by vertical electron transfer. The A and B states undergo rate-determining internal conversion to vibrationally highly excited ground state that loses an H atom via two competing mechanisms. The first of these is the direct cleavage of one of the O-H bonds in 1. The other is an isomerization to 3 followed by cleavage of the P-H bond to form O=P-OH as a stable product. The relative, dissociation, and transition state energies for the ions and neutrals were studied by ab initio and density functional theory calculations up to the QCISD(T)/6-311+G(3df,2p) and CCSD(T)/aug-cc-pVTZ levels of theory. RRKM calculations were performed to investigate unimolecular dissociation kinetics of 1. Excited state geometries and energies were investigated by a combination of configuration interaction singles and time-dependent density functional theory calculations.

Role of rice and cereal products in dietary cadmium and lead intake among different socio-economic groups in south India

A study was conducted to evaluate the concentration of cadmium and lead in rice and cereal products commonly consumed in South India. Samples from retail outlets were purchased and analysed for cadmium and lead using graphite tube atomic absorption spectrophotometry. The results indicated varying concentrations of these metals in different rice and cereal products. The daily dietary intake of cadmium and lead varied among different socio-economic groups, based on occupation, and choice of consumption. The findings suggest that rice is the major source of cadmium and lead among the rural population and economically-deprived class. The source of intake of toxic metals appears to be more diverse in the case of the urban middle class and the economically privileged class of South India.

Cadmium levels in the urine of male sewage sludge farmers of Hyderabad, India

A study was conducted to evaluate the urinary cadmium levels among 45 nonsmoking sewage sludge farmers of different age groups and exposure. Urinary cadmium was analyzed following standard procedures on a flameless atomic absorption spectrophotometer. Cadmium concentrations were found to be significantly higher when compared with a nonsmoking general population of similar age group with no occupational exposure to cadmium. The mean concentration of 7.07 micrograms/L of cadmium was found in the farmers exposed to 25 yr of working on the sludge farms. Significantly higher concentrations of cadmium were also detected in the farmers exposed to 10 yr of working on sludge farms when compared with that of control groups.