Injection Molding of Long Fiber Reinforced Thermoplastic Composites

Long fiber reinforced thermoplastic composites are one of the fastest growing segments experiencing 30% growth per year, over the last decade. This study describes the development of long fiber reinforced thermoplastic (LFRT) composites and the effect of fiber length on mold and process parameters of injection molding process. LFRT pellets of different sizes were prepared by an extrusion process using a specially designed impregnation die and palletized into different lengths. These pellets were injection molded to develop LFRT composites. Fiber length distributions were analyzed using a profile projector and an image analyzer software system. Maleic anhydride grafted polypropylene (MA-g-PP) was added to improve the adhesion between glass fibers and polypropylene. Improvement in mechanical properties were analyzed for different pellet sizes with different fiber content for long fiber reinforced polypropylene (LFPP) and long fiber reinforced polyamide (LFPA) composite.

Epidural volume extension: a review

Epidural volume extension is a technical modification of the combined spinal epidural block. It involves the epidural injection of normal saline or a small volume of local anaesthetic after an intrathecal injection, aiming to augment the post-spinal sensory level. Although the consequent sensory block augmentation has been adequately documented, the probable factors influencing epidural volume extension and its implications for clinical practice are not well defined. This article reviews published literature relating to the probable factors affecting epidural volume extension, its clinical implications, case reports of its successful clinical application and summarises its unexplored effects.

Cloning and characterization of a gene encoding novel zinc finger protein transcription factor induced under water deficit stress from rice (Oryza sativa) cv. N-22

A gene OsZnI encoding Cys3/His1-type zinc finger protein was isolated from the water stress-induced cDNA library of rice (Oryza sativa) cv. N-22, an early maturing, deep-rooted, drought-tolerant genotype adapted to upland conditions. The in-silico analysis revealed an insert of 800 bp with an ORF of 663 nucleotides, encoding 221 amino acids. OsZnI had three distinct features--nuclear localization signal (NLS) present in Arg152-Arg168, Zn finger domain between 185-193 amino acids and 12 amino acids conserved domain in 71-82 amino acids homologous to LEA motif, and belonged to C-type family of Zn finger protein. OsZnI showed induced expression under water deficit stress.

A comparison of pressure-controlled and volume-controlled ventilation for laparoscopic cholecystectomy

The potential advantages of pressure-controlled over volume-controlled ventilation during laparoscopic surgery have yet to be proven. We randomly assigned 42 patients with BMI <30 kg.m(-2) scheduled for laparoscopic cholecystectomy to receive either pressure- or volume-controlled ventilation. Compared with volume-controlled ventilation, pressure-controlled ventilation resulted in a significant decrease in mean (SD) peak airway pressure at 10 min (20.4 (2.7) vs 24.0 (4.7)cmH₂O, p=0.004) and 30 min (20.7 (3.0) vs 23.9 (4.9)cmH₂O, p=0.015) and an increase in mean airway pressure at 10 min (10.5 (0.9) vs 9.6 (1.1)cmH₂O, p=0.007) and 30 min (10.5 (1.1) vs 9.6 (1.2)cmH₂O, p=0.016) after the start of surgery. Gas exchange and haemodynamic stability were similar. We conclude that pressure-controlled ventilation is a safe alternative and offers some advantages to volume-controlled ventilation during laparoscopic cholecystectomy in non-obese patients.

Comparison of phenylephrine hydrochloride and mephentermine sulphate for prevention of post spinal hypotension

This study compared the effects of intravenous infusions of phenylephrine and mephentermine on the prevention of maternal hypotension and neonatal outcome in patients receiving spinal anaesthesia for caesarean section. Sixty ASA 1-2 patients with term, uncomplicated singleton pregnancy undergoing caesarean section under spinal anaesthesia were randomly divided into two groups of 30 each, to receive a prophylactic intravenous infusion of either phenylephrine or mephentermine. The incidence of hypotension was statistically similar in the two groups. However, in patients receiving phenylephrine, 7 (23%) developed bradycardia and 6 (20%), reactive hypertension. Neonatal outcome, in terms of Apgar scores and umbilical artery pH, was similar in both the groups. To conclude, phenylephrine and mephentermine infusions are equally effective in preventing post spinal hypotension in patients undergoing caesarean section and are associated with a similar neonatal outcome.

Photophysical characterisation and photo-cycle dynamics of LOV1-His domain of phototropin from Chlamydomonas reinhardtii with roseoflavin monophosphate cofactor

The wild-type phototropin protein phot from the green alga Chlamydomonas reinhardtii with the blue-light photoreceptor domains LOV1 and LOV2 has flavin mononucleotide (FMN) as cofactor. For the LOV1-His domain from phot of C. reinhardtii studied here, the FMN chromophore was replaced by roseoflavin monophosphate (8-dimethylamino-8-demethyl-FMN, RoFMN) during heterologous expression in a riboflavin auxotropic Escherichia coli strain. An absorption and emission spectroscopic characterisation of the cofactor exchanged-LOV1-His (RoLOV1) domain was carried out in aqueous pH 8 phosphate buffer. The fluorescence of RoLOV1 is quenched by photo-induced charge transfer at room temperature. The photo-cyclic dynamics of RoLOV1 was observed by blue-light induced hypochromic and bathochromic absorption changes which recover on a minute timescale in the dark. Photo-excited RoFMN is thought to cause reversible protein and cofactor structural changes. Prolonged intense blue-light exposure caused photo-degradation of RoFMN in RoLOV1 to fully reduced flavin and lumichrome derivatives. Photo-cycle schemes of RoLOV1 and LOV1 are presented, and the photo-degradation dynamics of RoLOV1 is discussed.

Construction of titanium cranioplasty plate using craniectomy bone flap as template

In recent times a steady rise in cranioplasty operations has been noted because of increasing utilisation of decompressive craniectomy for trauma as well as stroke patients. A variety of techniques have been utilised for cranioplasty, with their own benefits and limitations. Titanium cranioplasty is one of the well-established and widely used techniques, with most centres utilising computer-assisted reconstruction for manufacture of titanium plates. In this paper we present a novel method for making titanium cranioplasty plates using the craniectomy bone flap as a template and the results of our experience. To date we have performed 51 cranioplasties using this method. The surgical results have been comparable to those obtained using the computer-assisted model technique. The construction cost for titanium cranioplasty plates using this method has been pound 360 cheaper per plate compared with the computer-assisted method. In addition, the CT workload and radiation exposure have been reduced.

Subdural Block and the Anaesthetist

There are a number of case reports describing accidental subdural block during the performance of subarachnoid or epidural anaesthesia. However, it appears that subdural drug deposition remains a poorly understood complication of neuraxial anaesthesia. The clinical presentation may often be attributed to other causes. Subdural injection of local anaesthetic can present as high sensory block, sometimes even involving the cranial nerves due to extension of the subdural space into the cranium. The block is disproportionate to the amount of drug injected, often with sparing of sympathetic and motor fibres. On the other hand, the subdural deposition can also lead to failure of the intended block. The variable presentation can be explained by the anatomy of this space. High suspicion in the presence of predisposing factors and early detection could prevent further complications. This review aims at increasing awareness amongst anaesthetists about inadvertent subdural block. It reviews the relevant anatomy, incidence, predisposing factors, presentation, diagnosis and management of unintentional subdural block during the performance of neuraxial anaesthesia.

Potency of mephentermine for prevention of post-spinal hypotension

This study was designed to determine the minimum effective dose (ED50) of mephentermine for prevention of post-spinal hypotension in women undergoing elective caesarean section. Dixon's up-down method of sequential allocation was used to determine the patient's dose of vasopressor drug. In our previous study, mephentermine appeared to be much more potent than ephedrine, so the present study was conducted using a lower initial dose and smaller dose interval for this vasopressor. Following administration of spinal anaesthesia, a prophylactic infusion of mephentermine was started with 5 mg infused over a period of 30 minutes as the initial dose and a dose interval of 1 mg. The ED50 of mephentermine of 3.7 mg (95% confidence interval 2.4 to 5.7 mg) was much less than that of ephedrine, as calculated in our previous study using the same methodology. Using these values gives a potency ratio of ephedrine to mephentermine of 1:6.8 (95% confidence interval 6.0 to 7.5).

Issues raised by a case of orbital metastatic disease

The clinical, radiological and histopathological findings in an 81-year-old man presenting with lung carcinoma metastatic to the orbit are described. Orbital biopsy was complicated by postoperative visual loss and failed to contribute significantly to the final diagnosis. The authors believe that in cases of possible orbital metastases a primary neoplasm should be excluded by means of a complete oncological assessment before proceeding to biopsy.

MIB1 proliferation index in meningiomas: does it predict recurrence? A clinicopathological study

The usefulness of proliferation marker MIB1 in predicting recurrences in cranial meningiomas when other clinical and pathological factors are considered was assessed. Data from 65 patients with meningiomas were analysed and their clinical notes reviewed to define the Simpson grade of surgical excision, the location of tumour, amongst other clinical factors. The diagnosis was reviewed; immunohistochemical staining for a proliferation marker MIB1 was carried out on archival formalin-fixed, paraffin-embedded tumour and a labelling index for MIB1 (MIB1 L1) calculated. Analysis was undertaken of the impact of histology, grade of excision, tumour location and proliferation index on the risk of recurrence. The grade of surgical resection and histology type were the most important factors likely to predict recurrence. MIB1 LI was not considered useful in predicting tumour recurrence.

Single-shot spinal anaesthesia, combined spinal-epidural and epidural volume extension for elective caesarean section: a randomized comparison

BACKGROUND

Single-shot spinal and combined spinal-epidural block, with or without epidural volume extension, can be used for caesarean section. There is no trial comparing their block characteristics and adverse effects under identical conditions.

METHODS

60 ASA I or II parturients with gestational age 37 weeks or more, scheduled for elective caesarean section under regional anaesthesia, were included in the trial. Women were randomized to three groups: group SSS: single-shot spinal; group CSE: combined spinal-epidural; group EVE: epidural volume extension of a combined spinal-epidural. Intrathecal injection was identical in the three groups (0.5% hyperbaric bupivacaine 9 mg with fentanyl 10 microg) and was injected via a 25-gauge pencil-point spinal needle, either as a single-shot spinal or through the spinal needle of the needle-through-needle CSE set. In group EVE, 5 mL of normal saline was injected through the epidural catheter. All blocks were performed with the women sitting. Haemodynamic parameters and block characteristics were assessed.

RESULTS

The onset of maximum sensory and motor block was significantly faster in the SSS group than in the other two. Extent and duration of sensory and motor block and the incidence of adverse effects were similar in the three groups (P>0.05).

CONCLUSIONS

Intrathecal block is similar in extent and duration whether given as a single-shot spinal or a combined spinal-epidural with or without epidural volume extension when performed for elective caesarean section using hyperbaric bupivacaine in the sitting position.

Cloning and characterization of drought responsive partial gene sequence(s) from Oryza sativa L. subsp. Indica

Differential display gels were run for the drought tolerant (N-22) and drought susceptible (Panidhan) genotypes of rice (Oryza sativa) to identify the genes showing differential expression with respect to moisture stress. Differential cDNA products were cloned in PCR-Trap vector and analyzed for differential expression by Northern hybridization. Two clones namely R4A and R7G were found to be associated with water deficit stress (WDS). Sequencing revealed an insert of 244 bp in the clone R4A. BLASTN and FASTA results showed that R4A had maximum homology with a full-length cDNA clone: 002-110-H10 and OSJNBa006109.12 protein. GO classification suggested that it had beta-glucosidase motif which had been implicated in ABA mobilization and thereby ABA dependent gene expression.

Determination of chloramphenicol in shrimp by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS)

A liquid chromatographic method with electrospray ionization tandem mass spectrometric (LC-ESI-MS-MS) detection and identification is described for the determination of chloramphenicol (CAP) in shrimp tissue. Homogenized shrimp samples were extracted by liquid-liquid extraction using ethyl acetate. d5-Chloramphenicol (5D-CAP) was used as the internal standard. Data acquisition was in negative-ion multiple reaction monitoring (NMRM) mode using three transition reactions for CAP (m/z 321 --> 152, m/z 321 --> 257 and m/z 321 --> 194) and two for d5-chloramphenicol (m/z 326 --> 262 and m/z 326 --> 157). Method validation was carried out according to European Commission decision 2002/657/EC. The calibration curve was linear in the range 0.10-2.00 microg l(-1), with typical r2 > 0.99. The decision limit (CC alpha) and detection capability (CC beta) were 0.06 and 0.10 microg kg(-1), respectively. There was no influence of the matrix on the determination of chloramphenicol.

Comparison of potency of ephedrine and mephentermine for prevention of post-spinal hypotension in caesarean section

The dosages and potency of intravenous mephentermine for prevention of post-spinal hypotension are not available in English literature. This study was designed to determine the minimum effective dose (ED50) of mephentermine and to compare its potency with that of ephedrine for prevention of post-spinal hypotension in parturients undergoing caesarean section. Dixon's up-down method of sequential allocation was used for vasopressor doses. Following administration of spinal anaesthesia, patients received a prophylactic infusion with 50 mg infused over a period of 30 minutes as the initial dose and dose intervals of 5 mg, of either ephedrine or mephentermine. The ED50 of ephedrine was 25.0 mg (95% CI 15.5 to 40.4 mg). For mephentermine, the up-down method was abandoned due to the success of the minimum dose possible but the ED50 appeared to be less than 5 mg. In conclusion, the minimum effective dose of mephentermine is much less than that of ephedrine for prevention of post-spinal hypotension. Another trial with a lower starting dose and smaller dose interval of mephentermine is required to determine the potency ratio of mephentermine and ephedrine.

The association of Brahma with the Balbiani ring 1 gene of Chironomus tentans studied by immunoelectron microscopy and chromatin immunoprecipitation

Many steps of gene expression take place during transcription, and important functional information can thus be obtained by determining the distribution of specific factors along a transcribed gene. The Balbiani ring (BR) genes of the dipteran Chironomus tentans constitute a unique system for mapping the association of specific factors along a eukaryotic gene using immuno-electron microscopy (immuno-EM). The chromatin immunoprecipitation (ChIP) technique has provided an alternative, more general method for studying the association of proteins with specific genomic sequences. The immuno-EM and the ChIP methods suffer from different limitations, and thus a combination of both is advantageous. We have established optimal conditions for ChIP on chromatin extracted from the salivary glands of C. tentans , and we have analyzed the association of the SWI/SNF chromatin remodelling factor Brahma (Brm) with the BR1 gene by combined immuno-EM and ChIP. We show that Brm is not restricted to the promoter of the BR1 gene but is also associated with sequences in the middle and distal portions of the gene, which suggests that Brm has additional roles apart from regulating transcription initiation.

The use of titanium non-penetrating clips to close the spinal dura

We present the results of our initial experience in the use of non-penetrating titanium clips in the closure of spinal dura. A retrospective analysis of case notes of patients identified from the unit database was carried out, limited to adults. A proforma that included demographic details, the diagnosis, the procedure undertaken, whether or not additional dural closure methods were used, the use of bed rest and any complications, including cerebrospinal fluid (CSF) leak. There were 58 patients with a mean age of 53 years. The commonest diagnoses were meningioma, ependymoma and neurofibroma. Eight patients had additional methods of dural closure used and approximately half the patients had a period of postoperative bed rest. Eight patients (13.7%) had a CSF leak. Our early experience with the use of non-penetrating clips for the closure of the spinal dura is presented. We have found them easy to use, especially in anatomically-restricted spaces and rapid in their application. However, our results have revealed an unexpectedly high complication rate. A further prospective study to evaluate them more fully is planned.

Compensator-based intensity-modulated radiotherapy in head and neck cancer: our experience in achieving dosimetric parameters and their clinical correlation

AIMS

To review the Batra Hospital and Medical Research Centre experience of using compensator-based intensity-modulated radiotherapy (IMRT) to treat head and neck cancer.

MATERIALS AND METHODS

Between October 2003 and August 2004, 18 patients underwent IMRT for head and neck cancer at our institution. IMRT was delivered using partial transmission high-resolution compensator blocks.

RESULTS

With a median follow-up of 13.3 months, two patients had residual disease and two failed in the gross tumour volume (GTV). The complete response rate after surgical salvage was 94.5%. Both the locoregional relapse-free and disease-free survival rates were 81.8%. The target coverage in terms of average maximum, mean and minimum dose (in Gy) delivered was 78.6, 73.5 and 58.4 to the GTV-planning target volume, 82.3, 70.9 and 47.3 to clinical target volume 1 (CTV1) and 82.9, 66.2 and 29.6 to CTV2. The dose constraint of 30 Gy to less than 50% of the contralateral parotid volume was achieved in 12 (66.7%) patients. If the dose constraint was revised to 35 Gy, at least 50% of the parotid volume was spared in 17 (94.5%) patients. On average, 75% of the contralateral parotid volume received a dose less than 35 Gy in 13 (72.3%) patients with grade I xerostomia, whereas this was 49.3% in five (27.7%) patients with grade II xerostomia, and the difference was statistically significant (P = 0.001).

CONCLUSIONS

In our initial experience, compensator-based IMRT is feasible with regard to target coverage and parotid volume sparing. The parotid volume dose has significant clinical implications on the grade of xerostomia. Our results invoke rethinking into the issues of the parotid volume dose constraint in our subpopulation.

Isolation of stress responsive Psb A gene from rice (Oryza sativa l.) using differential display

Differential display (DD) experiments were performed on drought-tolerant rice (Oryza sativa L.) genotype N22 to identify both upregulated and downregulated partial cDNAs with respect to moisture stress. DNA polymorphism was detected between drought-stressed and control leaf tissues on the DD gels. A partial cDNA showing differential expression, with respect to moisture stress was isolated from the gel. Northern blotting analysis was performed using this cDNA as a probe and it was observed that mRNA corresponding to this transcript was accumulated to high level in rice leaves under water deficit stress. At the DNA sequence level, the partial cDNA showed homology with psb A gene encoding for Dl protein.

Laryngotracheal hypoplasia--a rare cause of difficult intubation

Generalized hypoplasia of the larynx and trachea is a very rare condition with only one case reported in the literature. A pregnant woman presented for an emergency laparotomy under general anaesthesia. Endotracheal intubation with conventional sizes of tracheal tubes failed, despite a Cormack and Lehane grade I laryngoscopic view. Subsequent investigations demonstrated generalized hypoplasia of the larynx and trachea. In this report, successful anaesthetic management of this case is discussed along with other possible options.

Expression of delta1-pyrroline-5-carboxylate synthetase gene during drought in rice (Oryza sativa L.)

The 45-days-old seedlings of drought resistant (N-22, CR143-2-2) and susceptible rice (Oryza sativa L.) genotypes (Panidhan, Pusa-169) were subjected to osmotic stress in PEG-6000 solution of -10 and -16 bar and the relative water content (RWC), proline content, and pyrroline-5-carboxylate synthetase (P5CS) activity and its P5CS expression were studied. A gradual decrease in RWC was observed in tolerant genotypes, whereas the decrease was drastic in susceptible ones. Proline content and P5CS activity increased both in susceptible and tolerant genotypes; the increase was higher in tolerant genotypes. Higher proline levels in tolerant genotypes were due to increased P5CS activity. The EcoRI, BamHI and XbaI restricted DNA of N-22 and Panidhan genotypes were hybridized with Arabidopsis P5CS sequence and a single band (approx 2.4 kb) was observed, however, P5CS expression was more in N-22 as compared to Panidhan.

Cerebral phaeohyphomycosis caused by Fonsecaea monophora

We report a case of cerebral phaeohyphomycosis in a 53-year-old immunocompetent diabetic male, caused by Fonsecaea monophora. Computerized tomography of the brain revealed an abscess, which yielded F. monophora in pure culture. The patient's condition deteriorated on treatment with voriconazole and 5-fluorocytosine, and improved subsequently with high-dose itraconazole. The genus Fonsecaea has recently been revised and the new species F. monophora generated from molecular analysis of isolates, most of which were originally identified as Fonsecaea pedrosoi. This is the fourth case of cerebral infection known to have been caused by F. monophora, although only the first reported as such. These cases suggest that the clinical potential of F. monophora differs from that of F. pedrosoi, one of the main agents of chromoblastomycosis, with F. monophora being predominantly neurotropic in the human host.