How spin relaxes and dephases in bulk halide perovskites

Spintronics in halide perovskites has drawn significant attention in recent years, due to their highly tunable spin-orbit fields and intriguing interplay with lattice symmetry. Here, we perform first-principles calculations to determine the spin relaxation time (T1) and ensemble spin dephasing time ([Formula: see text]) in a prototype halide perovskite, CsPbBr3. To accurately capture spin dephasing in external magnetic fields we determine the Landé g-factor from first principles and take it into account in our calculations. These allow us to predict intrinsic spin lifetimes as an upper bound for experiments, identify the dominant spin relaxation pathways, and evaluate the dependence on temperature, external fields, carrier density, and impurities. We find that the Fröhlich interaction that dominates carrier relaxation contributes negligibly to spin relaxation, consistent with the spin-conserving nature of this interaction. Our theoretical approach may lead to new strategies to optimize spin and carrier transport properties.

Spin-polarized electronic properties of naphthylene-based carbon nanostructures

The 2D naphthylene-β structure is a theoretically proposed sp² nanocarbon allotrope based on the assembly of naphthalene-based molecular building blocks, which features metallic properties. We report that 2D naphthylene-β structures host a spin-polarized configuration which turns the system into a semiconductor. We analyze this electronic state in terms of the bipartition of the lattice. In addition, we study the electronic properties of nanotubes obtained from the rolling up of 2D naphthylene-β. We show that they inherit the properties of the parent 2D nanostructure, such as the emergence of spin-polarized configurations. We further rationalize the results in terms of a zone-folding scheme. We also show that the electronic properties can be modulated using an external transverse electric field, including a semiconducting-to-metallic transition for sufficiently large field strength.

Correction: Abou-Elnour et al. Investigation of the Optical Properties for Quaternary Se60-xGe35Ga5Sbx (x = 0, 5, and 10) Chalcogenide Glass. Materials 2022, 15, 6403

The authors would like to make a correction in a recently published paper [...].

Investigation of the Optical Properties for Quaternary Se60-xGe35Ga5Sbx (x = 0, 5, and 10) Chalcogenide Glass

A quenching technique was used to prepare the chalcogenide system of the Se60−xGe35Ga5Sbx (x = 0, 5, and 10 at. %), which was deposited as thin films onto glass substrates using a thermal evaporation technique. X-ray diffraction patterns were used for structure examination of the fabricated compositions, which exposes the amorphous nature of the deposited samples. Meanwhile, the chemical compositions of the prepared samples were evaluated and calculated via the energy-dispersive X-ray spectroscopy (EDX), which was in agreement with the measured compositional element percentages of the prepared samples. Based on the optical reflectance R and transmittance T spectra from the recorded spectrophotometric data ranging from 350 to 2500 nm, the influence of the Sb element on the Se60−xGe35Ga5Sbx thin films’ optical properties was studied. The film thickness and the refractive index were calculated via Swanepoel’s technique from optical transmittance data. It has been observed that the films’ refractive index increases with increasing x value over the spectral range. The refractive index data were used to evaluate the dielectric constants and estimate dispersion parameters Eo and Ed using the Wemple−DiDomenico model. The optical energy gap Egopt was calculated for the tested compositions. The result of the optical absorption analysis shows the presence of allowed direct and indirect transitions.

223 Development of Online Surgical Skills Education

Introduction

Online teaching rapidly emerged as a viable alternative to traditional face-to-face education. However, how to teach surgical skills in the online environment has not been established nor evaluated yet.

Method

An international one-day online surgical skills course consisting of lectures, pre-recorded virtual workshops, live demonstrations, and surgical skills teaching in breakout rooms was organised. Simultaneously, a traditional face-to-face surgical skills teaching was held and used as benchmark. Skills development assessed by trained demonstrators and self-reported competency scores were compared between the online and face-to-face event.

Results

In total, 553 participants from 20 different countries attended the online course, 64 were trained in breakout rooms with a 1:5 demonstrator to candidate ratio whilst the remaining candidates participated in didactic skills development sessions. In a separate face-to-face course 20 candidates were trained with traditional methods. Post course competency ratings by demonstrators in suturing, tendon repair and vascular anastomosis were not significantly different between students receiving online breakout room or face-to-face teaching (ps>0.05). The development of the same skills to “articulation” were not different between formats (ps>0.05). Post course self-rated competency scores improved for all technical skills (p<0.001). Small group sessions, both online and face-to-face, received higher satisfaction ratings compared to large group sessions in terms of clarity of instructions, answers to questions and demonstrator feedback.

Conclusions

Online teaching of surgical skills for early training years is an appropriate alternative to face-to-face teaching with the ability to define clear learning objectives, effectively teach surgical skills and achieve similar learning outcomes.

868 The management of acute lower gastrointestinal bleeding using a Sengstaken-Blakemore tube

Introduction

Acute lower gastrointestinal haemorrhage can potentially be life-threatening. We present a case of a massive rectal bleed which was managed successfully with a balloon tamponade device designed for upper gastrointestinal haemorrhage.

Presentation of case

A 75-year-old gentleman, with a history of human immunodeficiency virus and cirrhosis with portal hypertension, presented with bright red rectal bleeding. Investigations showed a low haemoglobin level (74 g/L) and deranged clotting. Oesophago-gastro-duodenoscopy demonstrated no fresh or altered blood. Flexible sigmoidoscopy revealed active bleeding from a varix within the anterior rectal wall 4 cm from the anal verge. Efforts to stop the bleeding, including endoscopic clips, adrenaline injection and rectal packing, were unsuccessful and the patient became haemodynamically unstable. A Sengstaken-Blakemore tube was inserted per rectum and the gastric balloon was inflated to tamponade the lower rectum. The oesophageal balloon was then inflated to hold the gastric balloon firmly in place. A computed tomography angiogram demonstrated no evidence of haemorrhage with balloon tamponade. After 36 h, the balloon was removed with no further episodes of bleeding.

Discussion

The application of a balloon tamponade device should be considered in the management algorithm for acute lower gastrointestinal bleed. Advantages include its rapid insertion, immediate results and ability to measure further bleeding after the catheter has been placed.

Conclusions

Sengstaken-Blakemore tube per rectum may effectively control massive low rectal bleeding when alternative methods have been unsuccessful.

593 Colonic Perforation Following Major Burns: A Systematic Review

Introduction

Major burns complicated by stress ulceration and perforation of the stomach or duodenum is a recognised clinical phenomenon. Colonic perforation in burns patients is seemingly uncommon, and the overall incidence, clinical signs/diagnosis of perforation, intervention required, and mortality is incompletely described in the literature.

Method

We performed a systematic review of the literature on severe burns resulting in colonic perforation during admission. Relevant studies from January 1975 to June 2020 were retrieved from MEDLINE and EMBASE databases. Patient demographics, total body surface area (TBSA), site of colonic perforation, management and overall outcome were extracted. We present a case series of five major burns patients who had colonic perforations in our Specialist Burns Centre.

Results

We identified 54 studies, of which nine (two case series and seven case reports) met the inclusion criteria. In most cases, the TBSA associated with a colonic perforation was ≥ 30% (10/16 patients, 63%) and the abdomen was involved in 9/16 patients (56%). Perforations mainly affected the right colon (12/16 patients, 75%), usually occurring after the second week of admission (13/16 patients, 81%). Right-sided colonic perforations were associated with an increased mortality rate compared to left-sided perforations (42% vs 25%).

Conclusions

The current literature, mainly limited to case series and case reports, confirms that colonic perforations in burns patients are rare. The resulting perforation is related to the systemic effect of burn injuries including sepsis and gastrointestinal stasis. We have identified patients who are at higher risk of developing colonic perforations in order to prompt early diagnosis and intervention.

1252 A Systematic Review of International Colorectal Multidisciplinary Team Meetings: The Development of Best Practice Through Inter-Regional Learning

Aim

Colorectal multi-disciplinary teams (CR MDTs) were introduced to enhance the cancer care pathway and allow for early investigation and treatment of colorectal cancer. However, there are no gold standards set for this process. The aim of this study is to establish recommendations on the principles, organisation, structure and output of CR MDTs internationally.

Method

The available literature on the role of CR MDTs from January 1999 and March 2020 in the United Kingdom (UK), United States of America (USA) and continental Europe was evaluated. Historical background, structure, core members, education, frequency, patient selection criteria, quality assurance, output and outcomes were extracted from data from the UK, USA, and continental Europe.

Results

Fifty studies were identified that specifically met the inclusion criteria. CR MDTs should occur at least once a month with established key members. Generally, all colorectal cancer patients should be discussed and there should be a focus on education. There are noted differences in the lead member of the CR MDT, the use of information technology and storage of MDT information in databases and quality assurance internationally.

Conclusions

The most common issues facing MDTs internationally include a lack of staffing and resources as well as limited information on the patient’s fitness and preference for surgery. These factors are important and urgent improvements are required in these areas in CR MDTs. Quality assurance should be a mandatory component of every CR MDT.

Matrice emplois-exposition pour le SARS-CoV-2 (COVID-19) : création de « Mat-O-Covid », validité et perspectives

L’évaluation de l’exposition est difficile pour le chercheur du domaine des risques professionnels. L’objectif du travail est de développer et de valider une matrice emplois-exposition (MEE) pour l’exposition professionnelle au SARS-CoV-2 appelée « Mat-O-Covid ». Grâce à un groupe d’expert français, la matrice a été développée pour tous les travailleurs sur la profession et les catégories socioprofessionnelles de 2003 (avec une passerelle de transcodage vers la Classification internationale type des professions de 2008) et un focus sur le secteur de soin et médicosocial. La moyenne des codages des experts a été utilisée comme estimation pour l’exposition « sujets » (collègues et/ou public) et « patients » pour le focus secteurs sanitaires, ainsi que la probabilité de prévention pour chaque. Les corrélations intraclasses ont été considérées comme bonnes à excellentes, sauf pour la prévention en santé. Comparées à la matrice américaine O*Net, l’évaluation a été considérée comme satisfaisante. En conclusion, une MEE « Mat-O-Covid » fournissant une probabilité d’exposition professionnelle au SARS-CoV-2 aura des implications pour la recherche et en santé publique, sous réserve de connaître ses limites et de poursuivre sa validation.

Tripentaphenes: two-dimensional acepentalene-based nanocarbon allotropes

Tripentaphenes are 2D nanocarbon lattices conceptually obtained from the assembly of acepentalene units. In this work, density functional theory is used to investigate their structural, electronic, and vibrational properties. Their bonding configuration is rationalized with a resonance mechanism, which is unique to each of the 2D assemblies. Their formation energies are found to lie within the range of other previously synthesized carbon nanostructures and phonon calculations indicate their dynamical stability. In addition, all studied tripentaphenes are metallic and display different features (e.g., Dirac cone) depending on the details of the atomic structure. The resonance structure also plays an important role in determining the electronic properties as it leads to delocalized electronic states, further highlighting the potential of the structures in nanoelectronics.

Enhancement of lipid productivity from a promising oleaginous fungus

Oleaginous fungi have recently gained increasing attention among different microorganisms due to their ability for lipid production for the preparation of biofuel. In the present study, a locally isolated fungus E45, identified genetically as Aspergillus sp. strain EM2018, was found to produce 25.2% of the total lipids content of its dry cell weight (DCW). Optimization of culture conditions was performed and lipid accumula­tion increased by about 2.4 fold (from 25.2% to 60.1% of DCW) when the fungus was grown for seven days in the potato dextrose (50 g/L) liquid medium at pH 5.0, incubation temperature at 30 ºC and inoculum size of 2 × 106 spore/mL. Supplementation of the medium with yeast extract and NaNO3 at a concentration of 0.05% as organic and inorganic nitrogen sources, respectively, increased lipid production (53.3% lipid/dry biomass). Gas chromatography analysis of fungal lipids revealed the presence of saturated (mainly palmitic acid C16:0 (33%) and lignoceric acid C24:0 (15%)) and unsaturated fatty acids in different proportions (mainly linoleic acid C18:2 (24.4%), oleica cid C18:1 (14%) and arachidonic C20:4 (7.4%). These findings suggest this new oleaginous fungus as a promising feedstock for various industrial applications and for the preparation of biodiesel.

Production of Glucoamylase, α-amylase and Cellulase by Aspergillus oryzae F-923 Cultivated on Wheat Bran under Solid State Fermentation

Filamentous fungi have been widely utilized in production of enzymes which have many industrial applications. In this study, twenty five local fungal isolates, belonging to Aspergillus sp., Trichoderma sp. and Penicillium sp., were screened under solid state fermentation conditions (SSF) for the production of α-amylase, glucoamylase and cellulase. Asperigillus oryzae F-923, cultivated on wheat bran, was the most promising isolate for production of the target enzymes under this study. Physical parameters of moisture content, pH, temperature and incubation time, optimized were 1:2(w/v), 5.5, 28°C and 72 hr, respectively. The production of enzymes was enhanced when ammonium sulfate was supplemented as a nitrogen source to wheat bran. The production of α-amylase and glucoamylase was also enhanced when 10% (w/w) soluble starch was added as a carbon source to wheat bran. However xylose supplementation at 10% (w/w) was observed to be best for cellulase production. Tap water was found to be efficient for enzymes' extraction from the fermentation medium. Three successive extractions were needed to obtain the produced enzymes from the fermented substrate. Characterization of the produced enzymes revealed that, the optimum temperature for α-amylase and glucoamylase was 60°C, while 50°C was the optimum temperature for cellulase activity. Isopropanol 1:1(v/v) was proved to be more suitable for partial purification of enzymes. Following partial purification of enzymes of glucoamylase, α-amylase and cellulase increased to 10.8, 11.8 and 11.4 folds, respectively.

Sun-protection and sun-exposure habits among sailors: results of the 2018 world's largest sailing race Barcolana' skin cancer prevention campaign

BACKGROUND

Epidemiologic data suggest an increased risk of melanoma (MM) and non-melanoma skin cancer (NMSC) in persons with intense recreational sun-exposure such as marathon runners or surfers. Up to data little is known about the sun-exposure habits, sun-protection behaviours and risk factors for MM and NMSC among sailors.

OBJECTIVE

The objective of this prospective, cross-sectional study was to investigate the sun-exposure and sun-protective habits and risk factors for skin cancer among sailors attending the 50° edition of Barcolana, the largest sailing race in of the world, which took place in October 2018 in Trieste, Italy as an integrative component of a public sun-prevention campaign.

METHODS

The study consisted of 2 parts: (i) a self-administered questionnaire focusing on sun-exposure and protective habits and (ii) a free skin examination carried out by volunteer dermatologists. Participation was optional and anonymous, and open to visitors and sailors attending the event.

RESULTS

Overall, 431 (52.4%) sailors and 391 (47.6%) visitors responded to the questionnaire, while a total of 437 individuals including 189 (43.3%) sailors and 248 (56.6%) visitors participated in the skin examination group. The majority of sailors reported a past history of severe sunburns (20.2%), applied sunscreen never (14.4%) to sometimes (45.7%) or only once daily (59%) on the face (55%) and shoulders (26%). Moreover, 14% of sailors had a personal history of non-melanoma skin cancer (NMSC). During the dermatological examination, suspicious lesions for skin cancer (including MM and NMSC) were identified in 37% of the sailors.

CONCLUSION

Our findings support the need to develop and promote primary and secondary prevention strategies to improve the sun-exposure and sun-protective habits among sailors.

Intravascular (post-hysterectomy) leiomyoma (IVL) as late tumor thrombus within the inferior vena cava (IVC)-A rare case primarily imposing as IVC thrombus originating from left renal vein after former left nephrectomy status

INTRODUCTION

Intravascular leiomyoma is a rare type of myoma. It was firstly described by Birch-Hirschfeld in 1896, however, its intracardiac subtype was firstly reported by Durck in 1907. Most patients are asymptomatic. The tumor invades mostly the tributaries of the inferior vena cava (IVC) with upward extension that may approach the intracardiac space.

AIM

By means of a scientific case report, a patient with the very rare diagnosis of an endocaval leiomyoma thrombus post-hysterectomy is described based on the clinical experiences obtained in the specific case management and selective references from the literature.

CASE PRESENTATION

A 48-years old female was diagnosed with intravascular tumor growth within the IVC with intracardiac extension using chest and abdominal CT scan, ECG and echocardiography which was approached by an interdisciplinary (vascular and cardiothoracic) surgical intervention (278 min) including heart-lung machine (99 min) with favorable postoperative result (R0 resection status with mid-term outcome, no recurrent tumor growth). Histopathological investigation diagnosed leiomyoma origin already from ovarian vein most likely in context to the former hysterectomy (3 years ago).

DISCUSSION AND CONCLUSION

Intravascular leiomyoma is a benign tumor with invasive tendency, which can be considered a diagnostic and therapeutic challenge. It should be thoroughly investigated to be planned for a radical surgical removal. By possible adherence to the intraabdominal or -thoracic organs, an interdisciplinary and eventually step-wise surgical approach (combining vascular, abdominal, thoracic and heart surgery as well as gynecology and urology), which can be demanding, is recommended to be seriously considered to i) reliably achieve R0 resection status and, thus, ii) provide best outcome, quality of life and prognosis.

Photovoltaic characteristics of natural light harvesting dye sensitized solar cells

In this work of research, anthocyanin as a natural dye obtained from raspberry fruits, was used and tested as a photon harvesting/electron donating dye in titanium dioxide nanoparticle-based DSSCs. A working photoelectrode made from TiO₂ nanoparticles with an average particle size (10-40nm) that is coated on Florine doped tin-oxide substrate, was prepared via a simple and low cost hydrothermal method. A detailed structural and morphological analysis of the TiO₂ photoactive electrode was investigated by X-ray diffraction (XRD), diffuse reflectance spectrometer, transmission electron microscope (TEM) and scanning electron microscope (SEM). Complete photovoltaic characteristics including (current, voltage, outpower, and responsivity) of the natural anthocyanin based dye sensitized solar cell have been investigated under different illumination intensity ranging from 10 to 100mW.cm^-2. The cell responsivity and efficiency of the fabricated solar cell under different illumination intensity were found to be in the range (R=15.6-23.8mA.W^-1 and η=0.13-0.25) at AM=1.5 conditions. This study is important for enhancing the future applications of the promising DSSC technology.

Occupational prognosis factors for ulnar nerve entrapment at the elbow: A systematic review

Although ulnar nerve entrapment is the second most common entrapment neuropathy, there is a dearth of studies identifying occupational prognosis factors. We carried out a systematic review of the occupational prognosis factors for ulnar nerve entrapment in order to identify professions at risks and allow better follow-up for their workers. Using the key words, "ulnar OR cubital", "neuropathy OR tunnel", and "work OR occupational" without limitations, original prospective studies were selected from four databases (PubMed, Embase, Web of Science, Cochrane Library) after two rounds (valid design, valid prognosis outcome reported, valid work exposure). Associations between prognosis for ulnar neuropathy and occupational factors were extracted and analyzed qualitatively. Dating from 1981 to 2013, three prospective studies were included; 1420 cases of ulnar nerve entrapment were followed for an average of 4 years and occupational exposure was retrieved. The only high-quality study (related to this question) found a significant relationship between occupational exposure and prognosis with an odds ratio for ulnar nerve entrapment of 1.78 (1.10-2.88). The two other studies were less focused on the occupational prognosis factors; one found that work activity requiring effort had worse prognosis after surgery, while the other found no significant relationship between occupational hand exposure and prognosis. Occupations requiring high effort may be associated with more severe ulnar neuropathies, but further studies (exposure as well as associated disorders) are mandatory for clinicians to provide work task information to their patients.

255 DIURNAL RHYTHMS OF GLUCOSE AND NON-ESTERIFIED FATTY ACID CONCENTRATIONS IN BLOOD IN HEAT-STRESSED DAIRY CATTLE IN EGYPT

The hyperthermia associated with summer heat stress (HS) is a major cause of reduced fertility in high yielding dairy cows in the tropics and subtropics. The hyperthermia directly affects reproductive function. Furthermore, HS induces indirect effects (e.g. through a dropped dry matter intake and thus an altered energy balance), which may also have an impact on cow fertility. The extent of exposure to HS and HS-associated metabolic changes, such as hypoglycemia and high levels of non-esterified fatty acids (NEFA), may affect cattle fertility by impairing the developmental capacity of the oocyte. It is known that changes in glucose and NEFA concentrations in the blood may be reflected in the follicular fluid of the dominant follicle (Leroy et al. 2004). Therefore, the aim of the current study was to estimate to what extent oocytes may be exposed to HS-associated metabolic changes in dairy cattle during summer by assessing the diurnal changes in plasma. Respiration rate (RR) and rectal temperature (RT) along with plasma concentrations of glucose and NEFA were examined in 10 lactating Holstein cows at 4-h intervals from 7:00 AM to 3:00 AM for three successive days in August 2007. Temperature humidity indices (THI) were calculated as well. Linear mixed effect models with cow as random factor including the effect of daytime were used to investigate possible differences among studied parameters at different daytimes. At 3:00 PM, THI and RT were the highest (83.7 ± 0.6 and 40.1 ± 0.1, respectively) and the lowest value for THI recorded at 3:00 AM (74.2 ± 1.4) and for RT recorded at 7:00 AM (39.04 ± 0.08). RR increased gradually from 66.1 ± 3.1 resp min–1 at 3:00 AM to 93.0 ± 4 resp min–1 at 11:00 AM. Glucose concentrations decreased significantly (P < 0.001) at 11:00 AM and 3:00 PM. Decreased glucose concentrations coincided with increased NEFA concentrations at 11:00 AM and 3:00 PM (P < 0.001). The NEFA concentrations measured at 3:00 PM were significantly higher than at all other time points (Table 1). In conclusion, high producing dairy cows may be exposed to diurnal fluctuation of HS-associated metabolic changes such as significantly decreased glucose and increased NEFA concentrations in plasma for about 12 h per day, which may be reflected in the follicular fluid of the dominant follicle and as such directly affect oocyte and granulosa cell quality. Table 1.Mean ± SEM of glucose and non-esterified fatty acids (NEFA) concentrations (mmol L–1) in blood plasma of 10 lactating Holstein cows at 6 different daytimes during August 2007 in Egypt

Ilizarov external fixator for open fractures of the tibial shaft

Between December 1993 and 1999 we treated 34 open tibial diaphyseal fractures. Thirty patients were available for evaluation with a mean follow-up after fracture union of 40.5 (24-80) months. Patient average age was 33.1 (15-71) years. Two fractures were grade I, 16 grade II, six grade IIIA, five grade IIIB and one grade IIIC. The wound was debrided and the bone fixed with Ilizarov device. Soft-tissue healing was achieved through Z-plasty, delayed primary closure, split-thickness skin grafting, pedicle flaps and skin traction, and all fractures united with an average 5.6 (3-15.4) months. In 28 patients the results were excellent and good, in one fair and in one poor. Despite numerous complications the use of Ilizarov external fixator provides initial and definitive fracture stability.

Inhibitory effect of lactoperoxidase-generated hypothiocyanite upon black pigmented anaerobe growth

This study aimed to evaluate the in vitro effect of lactoperoxidase with or without its substrates (hydrogen peroxide, thiocyanate) on the growth of 4 different black pigmented anaerobe (BPA) strains associated with the development and progress of periodontal diseases: Porphyromonas gingivalis ATCC 33277, Prevotella intermedia NCTC 9336, Prevotella loescheii ATCC 15930, and Prevotella melaninogenica NCTC 9338. A 5-min lactoperoxidase-generated OSCN--HOSCN incubation at pH 6.0, 7.0 or 8.0 resulted in a decrease of the growth rate (tested by turbidimetry in liquid cultures) of the 4 BPA strains, whilst lactoperoxidase alone actually promoted bacterial growth.

Salivary biomass assessed by bioluminescence ATP assay related to (bacterial and somatic) cell counts

The present work aimed (1) to evaluate ATP content in saliva by the bioluminescent luciferin-luciferase method, (2) to evaluate the relationships between ATP content, bacterial count and epithelial cell numbers in saliva, (3) to study the effect of two different antiseptics (peroxidase system producing hypothiocyanite and chlorhexidine) on the salivary biomass. In 45 young adults, the salivary ATP content ranged from 8 to 1515 nM. Salivary ATP content was significantly and directly correlated to bacterial count and epithelial cell numbers (Spearman-Rank correlation, P< or =0.001). Regression analysis allowed the inference of a mean epithelial cell and bacterial ATP content of 152.7 fg and 8.3 fg per cell, respectively. The salivary ATP content decreased significantly to 38. 8+/-12.3 per cent (mean+/-SEM, N=6) of its initial value after a 30-min incubation in the presence of a peroxidase system producing hypothiocyanite (OSCN(-)). Chlorhexidine (CHX) reduced salivary ATP content to 52.0+/-16.7 per cent. OSCN(-) did not affect the transformed logarithm of bacterial count but CHX reduced it from 7. 02+/-0.26 to 0.52+/-0.33. No effect of OSCN(-) was seen on the ratio of epithelial cell viability while CHX reduced it from 46.7+/-5.1 to 3.9+/-1.1 per cent. It is concluded that the combination of the evaluations of the ATP content and cell numbers in saliva can provide reliable data about the effects of oral antiseptics on salivary biomass.

Physiological studies on xylanase production by Penicillium funiculosum on some agricultural wastes

Studies were carried out on production of Xylanase enzyme from P. funiculosum NRCE-629 using a number of alkali-treated lignocellulosic wastes as carbon and energy sources as compared to pure xylan polymer. Sugar cane bagasse, rice straw and wheat straw yielded enzyme levels higher than that obtained on pure xylan. Physiological studies on enzyme formation using those three agricultural wastes revealed that optimum enzyme yields are obtained in media containing 2% substrate concentration. The enzyme synthesis was favored in agitated cultures with an air:medium ratio corresponding to 3:2 respectively with inoculum size of 10% (v/v). Further studies using rice straw medium yielded highest enzyme level after five days of aerobic growth at 30 degrees C with initial pH of medium adjusted to 5.0. Results are discussed in the light of possible application.