Differential response of Bay of Bengal during deficit and normal monsoons.

Present study explains the disparity in biological production (primary and secondary) with respect to two distinct monsoonal regimes in the western Bay of Bengal, viz., deficit monsoon (DM) and normal monsoon (NM). A combination of in situ and satellite data during the years 2002 (DM) and 2003 (NM) was used to address the physico-chemical and biological responses. The basin was relatively warm (ΔSST = 0.55 °C) and fresh (ΔSSS = -0.55) during DM than NM. Physical processes such as coastal upwelling and cyclonic eddy were prominent during NM. Variations of hydrography between DM and NM were reflected in the biological production as well. Chlorophyll a concentration (0.05 to 5.2 mg m-2) was almost similar during both the periods; however, column production showed higher values during DM. Mesozooplankton standing stock was relatively less during DM than NM. Composition of zooplankton also showed pronounced variation between the periods. This can be attributed to the variability in biological response of the region to the varying environmental condition. Relatively high chlorophyll a and primary productivity observed during DM may be due to the increased light availability (less cloud cover) and extended euphotic depth. In addition, the low mesozooplankton standing stock (low grazing) observed during the period also might have helped in maintaining a relatively high rate of production. The seasonal production of the basin is influenced by duration and intensity of various atmospheric as well as oceanic processes.

Response of micro- and mesozooplankton in the southwestern Bay of Bengal to a cyclonic eddy during the winter monsoon, 2005.

A cyclonic eddy (CE) in the southwestern Bay of Bengal (SWBoB; 10-15° N; 81-87° E) during winter monsoon 2005 and associated changes in the open ocean hydrography and productivity patterns were studied using satellite observations and in situ measurements. Analysis of the satellite-derived sea surface height anomaly (SSHA) indicated the existence of a large eddy (10-15° N; 81-87° E) from November to January, with its core centered at 13° N and 82° E. The large positive wind stress curl (~1.8 × 10(-7) N m(-2)) and resultant Ekman pumping (~3 × 10(-2) cm s(-1)) were identified as the prominent forcing mechanisms. In addition, the cyclonic storms and depressions experienced in the region during the study period seem to have served to maintain the strength of the CE through associated Ekman pumping. The cold (~26.6 °C), nutrient-enriched (NO3 > 2 µM, PO4 > 0.73 µM and SiO4 > 3 µM) upwelled waters in the upper layers of the CE enhanced the biological production (chl. a > 0.56 mg m(-3)). Dissolved oxygen in the surface waters was > 200 µM. The phytoplankton and zooplankton biomass recorded during the season was comparable or perhaps higher than the peak values reported from the northeastern Arabian Sea (chlorophyll a concentrations of 0.2 to 0.4 mg m(-3) and zooplankton biovolume 0.6 ml m(-3)) during winter. Occurrence of a higher mesozooplankton biovolume (0.8 ml m(-3)) and relatively low abundance of microzooplankton indicates the prevalence of a short food chain. In conclusion, high biological production, both at primary as well as secondary level, suggests the prevalence of an efficient food web as a result of physical forcing and subsequent ecological interactions evident up to tertiary level in an oligotrophic basin like BoB.

A comparative study on mesozooplankton abundance and diversity between a protected and an unprotected coastal area of Andaman Islands.

The study was carried out to understand the variability in phytoplankton production (Chlorophyll a) and mesozooplankton diversity from two different shallow coastal regions of south Andaman viz. Port Blair Bay (PBB), the only real urban area among the islands and Mahatma Gandhi Marine National Park, a Marine Protected Area (MPA) at Wandoor. Seasonal sampling was carried out during the Northeast monsoon (NEM--November 2005), Intermonsoon (IM--April 2006), and Southwest monsoon (SWM--August 2006). Significant (P < 0.05) seasonal variation was observed in the environmental variables at both the regions. Higher average chlorophyll a (Chl. a) and mesozooplankton standing stock were observed at PBB compared to MPA, but the seasonal variation observed was marginal at both the study areas. Chl. a showed a steep increasing gradient from outer to the inner regions of the PBB. The number of zooplankton taxa recorded at both areas was quite similar, but marked differences were noticed in their relative contribution to the total abundance. Eventhough the Copepoda dominated at both the areas, the non-copepod taxa differed significantly between the regions. Dominance of carnivores such as siphonophores and chaetognaths were noticed at PBB, while filter feeders such as appendicularians and decapod larvae were more abundant at MPA. A total of 20 and 21 copepod families was recorded from PBB and MPA, respectively. Eleven species of chaetognaths were observed as common at both areas. Larval decapods were found to be predominant at MPA with 20 families; whereas, at PBB, only 12 families were recorded. In the light of the recent reports on various changes occurring in the coastal waters of the Andaman Islands, it is suspected that the difference in Chl. a as well as the mesozooplankton standing stock and community structure observed between the two study areas may be related to the various anthropogenic events influencing the coastal waters.

Insights into the cumulative effect of Colletotrichum gloeosporioides and Fusarium acutatum causing anthracnose-twister disease complex of onion.

Colletotrichum is an important plant pathogenic fungi that causes anthracnose/-twister disease in onion. This disease was prevalent in the monsoon season from August to November months and the symptoms were observed in most of the fields. This study aimed to investigate the pathogenicity and cumulative effect, if any of Colletotrichum gloeosporioides and Fusarium acutatum. The pot experiment was laid out to identify the cause responsible for inciting anthracnose-twister disease, whether the Colletotrichum or Fusarium or both, or the interaction of pathogens and GA3. The results of the pathogenicity test confirmed that C. gloeosporioides and F. acutatum are both pathogenic. C. gloeosporioides caused twisting symptoms independently, while F.acutatum independently caused only neck elongation. The independent application of GA3 did not produce any symptoms, however, increased the plant height. The combined treatment of C. gloeosporioides and F. acutatum caused twisting, which enhanced upon interaction with GA3 application giving synergistic effect. The acervuli were found in lesions infected with C. gloeosporioides after 8 days of inoculation on the neck and leaf blades. Symptoms were not observed in untreated control plants. Koch's postulates were confirmed by reisolating the same pathogens from the infected plants.

Colonization potential of endophytes from halophytic plants growing in the "Runn of Kutch" salt marshes and their contribution to mitigating salt stress in tomato cultivation.

Increasing soil salinity depreciates the quantity of the crop produce. Looking at the tremendous potential of plant-associated microorganisms in salinity stress mitigation, it would be very useful in exploring and deciphering salt-tolerant microorganisms from halophytic plants and their utilization in cultivated plants. With this aim, in the present study, four halophytic plants were taken from Rann of Kutch, and bacterial endophytes were isolated from different plant organs. These endophytes were characterized by plant growth and health promotion features. The molecular identification was done based on 16 s rRNA sequence similarity. It was found that the endophytic bacteria isolated from 4 different halophytes found sharing phylogenetic relatedness. Four potential endophytes Alkalihalobacillus gibsonii 2H2, Achromobacter insuavis 2H18, Terribacillus halophilus 2H20, and Bacillus siamensis 4H1 were tested in tomato for salinity stress alleviation. Changes in the levels of antioxidants were analyzed. Total chlorophyll, total phenolics, malondialdehyde, and proline content indicated reduced damage in the plant system due to salinity by the application of endophytes. All the treatments exhibited low levels of electrolyte leakage. The accumulation of enzymatic reactive oxygen species scavengers was assessed from the levels of peroxidase, catalase, superoxide dismutase, phenylalanine ammonia-lyase, ascorbate peroxidase, and guiacol peroxidase. The NBT and DAB staining confirmed the findings. The reduction in the accumulation of Na+ ions in tomato leaves was visualized using Sodium Green probes under CSLM and found to be lowest in Terribacillus halophilus 2H20 and Bacillus siamensis 4H1 inoculated plants. The endophyte Terribacillus halophilus 2H20 was the most promising isolate. The colonization in tomato roots was confirmed using a cell tracker system. Results showed that the endophytes were found to have salinity stress mitigation traits. The efficiency could be further improved with the combination of other endophytes tested earlier.

Influence of different irrigant activation methods on apical debris extrusion and bacterial elimination from infected root canals.

Introduction: The study aimed to determine the apical debris extrusion and microbial elimination from infected root canals after using different irrigant activation methods. Materials and Methods: Forty freshly extracted human mandibular premolars were selected and randomly assigned to four groups (n = 10). The teeth were mechanically prepared, sterilized, and inoculated with Enterococcus faecalis for 1 week. Irrigation was done with 3% sodium hypochlorite following conventional syringe irrigation-Group 1, manual dynamic agitation (MDA)-Group 2, passive ultrasonic irrigation (PUI)-UltraX -Group 3, and sonic irrigation (SI)-EndoActivator -Group 4, and the extruded debris were collected using Myers and Montgomery model. The microbial samples were taken from the canals using sterile paper points, cultured and recorded as colonies. The amount of extruded debris was measured by subtracting the final weight of the Eppendorf tube with debris from the initial weight of the tube. Results: I. Group 3 showed the least apical debris extrusion (P < 0.05), followed by Groups 2 and 1 and the highest with Group 4. II. Group 3 showed the least colony-forming units (CFUs)/ml, followed by Group 4, and finally, Group 2 showed lesser mean CFUs/ml compared to Group 1 (P < 0.05). Conclusion: All the irrigation activation methods were associated with apical debris extrusion, with the PUI system extruding the least amount of debris compared to the other groups. Irrigation activation techniques were beneficial in reducing the microbial load from the infected canals with the PUI system showing a complete elimination of the microbes, followed by SI and MDA.

ROS generated from biotic stress: Effects on plants and alleviation by endophytic microbes.

Aerobic living is thought to generate reactive oxygen species (ROS), which are an inevitable chemical component. They are produced exclusively in cellular compartments in aerobic metabolism involving significant energy transfer and are regarded as by-products. ROS have a significant role in plant response to pathogenic stress, but the pattern varies between necrotrophs and biotrophs. A fine-tuned systemic induction system is involved in ROS-mediated disease development in plants. In regulated concentrations, ROS act as a signaling molecule and activate different pathways to suppress the pathogens. However, an excess of these ROS is deleterious to the plant system. Along with altering cell structure, ROS cause a variety of physiological reactions in plants that lower plant yield. ROS also degrade proteins, enzymes, nucleic acids, and other substances. Plants have their own mechanisms to overcome excess ROS and maintain homeostasis. Microbes, especially endophytes, have been reported to maintain ROS homeostasis in both biotic and abiotic stresses by multiple mechanisms. Endophytes themselves produce antioxidant compounds and also induce host plant machinery to supplement ROS scavenging. The structured reviews on how endophytes play a role in ROS homeostasis under biotic stress were very meager, so an attempt was made to compile the recent developments in ROS homeostasis using endophytes. This review deals with ROS production, mechanisms involved in ROS signaling, host plant mechanisms in alleviating oxidative stress, and the roles of endophytes in maintaining ROS homeostasis under biotic stress.

Mesozooplankton distribution near an active volcanic island in the Andaman Sea (Barren Island).

The study addresses the distribution and diversity of mesozooplankton near the active volcano-Barren Island (Andaman Sea) in the context of persistent volcanic signature and warm air pool existing for the last few months. Sampling was done from the stations along the west and east side of the volcano up to a depth of 1,000 m during the inter monsoon (April) of 2006. Existence of feeble warm air pool was noticed around the Island (Atm. Temp. 29°C). Sea surface temperature recorded as 29.9°C on the west and 29.6°C on the east side stations. High mesozooplankton biomass was observed in the study area than the earlier reports. High density and biomass observed in the surface layer decreased significantly to the deeper depths. Lack of correlation was observed between mesozooplankton biomass and density with chl. a. Twenty-three mesozooplankton taxa were observed with copepoda as the dominant taxa followed by chaetognatha. The relative abundance of chaetognatha considerably affected the copepod population density in the surface layer. A noticeable feature was the presence of cumaceans, a hyperbenthic fauna in the surface, mixed layer and thermocline layer on the western side station where the volcano discharges in to the sea. The dominant order of copepoda, the calanoida was represented by 52 species belonging to 17 families. The order poecilostomatoida also had a significant contribution. Copepods exhibited a clear difference in their distribution pattern in different depth layers. The families Calanidae and Pontellidae showed a clear dominance in the surface whereas small-sized copepods belonging to the families Clausocalanidae and Paracalanidae were observed as the predominant community in the mixed layer and thermocline layer depth. Families Metridinidae, Augaptilidae and Aetideidae were observed as dominant in deeper layers.

Solid state (13)C NMR analysis of human gallstones from cancer and benign gall bladder diseases.

Natural abundance (13)C cross polarized (CP) magic angle spinning (MAS) nuclear magnetic resonance (NMR) analysis of human gall bladder stones collected from patients suffering from malignant and benign gall bladder disease was carried out which revealed different polymorphs of cholesterol in these stones. All gall bladder stones in present study had cholesterol as their main constituent. (13)C CP-MAS NMR analysis revealed three forms of cholesterol molecules in these stones, which are anhydrous form, monohydrate crystalline with amorphous form and monohydrate crystalline form. Our study revealed that stones collected from patients associated with chronic cholecystitis (CC) disease have mostly different polymorph of cholesterol than stones collected from patients associated with gall bladder cancer (GBC). Such study will be helpful in understanding the mechanism of formation of gallstones which are associated with different gall bladder diseases. This is the first study by solid state NMR revealing different crystal polymorphism of cholesterol in human gallstones, extending the applicability of (13)C CP-MAS NMR technique for the routine study of gallstones.

Diabetic ketoacidosis in a buck: a case report.

BACKGROUND: Diabetic ketoacidosis (DKA) is a disorder of carbohydrate metabolism that causes frequent urination, emaciation, extreme tiredness and dehydration. There is little or no information available on DKA in male goat (buck). The present study was carried out to report a rare case of DKA in a buck. CASE DESCRIPTION: A 1.5 year old buck was presented with anorexia and cough. On physical examination of buck showed fever, dullness, poor body condition and pale conjunctival mucous membrane. FINDINGS/TREATMENT AND OUTCOME: The peripheral blood smear revealed the mixed infection of Theileria sp. and Anaplasma sp. The blood picture showed anaemia and leukocytosis. The animal was treated with buparvaquone )2.5 mg/kg( and long acting oxytetracycline (20 mg/kg). Post treatment evaluation was done 7 days after initial treatment. Animal showed mild improvement in feed intake, the body temperature becomes normal, but showed tachycardia with weak pulse. Subsequently, animal showed severe emaciation with frequent urination. Urinalysis revealed glycosuria, ketonuria and acidic urine (pH = 6.0). Serum biochemistry revealed hyperglycemia, hypoinsulinemia, increased level of fructosamine and triglycerides and confirmed spontaneous DKA. It was treated with biphasic isophane insulin (1.0 IU/kg) twice a day, regularly. The blood glucose level becomes normal after insulin therapy. Animal resumed adequate feed intake, improvement in haemoglobulin (Hb), packed cell volume (PCV), total erythrocyte count (TEC), and weight gain was observed. CONCLUSION: This case study gains significance, due to its successful recovery after insulin treatment, but it requires lifelong insulin therapy to manage insulin dependent diabetes mellitus (IDDM) in this goat.

Prevalence of haemoprotozoan diseases in cattle of Cauvery delta region of Tamil Nadu.

A study was carried out to determine the prevalence of haemoparasites in cattle in Cauvery delta region over a period of one year. A total of 228 giemsa stained blood smears were screened for the presence of haemoprotozoa, out of which 34 animals were found to be positive. An overall prevalence of haemoparasites in the sampled cattle were 14.9%, among this Anaplasma sp (8.3%), Babesia sp (3.95%), Theileria sp (2.19%) and Trypanosoma sp (0.44%) as single or mixed blood parasitic infections. In this study Anaplasmosis (14%) was highly prevalent during the winter season and Babesiosis (13.73%) was highly prevalent during summer months followed by Anaplasmosis (9.8%) and Theileriosis (7.8%), the lowest prevalence of Trypanosomiasis was observed during the rainy season. The seasonal variation in prevalence of haemoprotozoan disease might be due to influence of climatic factors on density of vector population in that geographical area. Haemogram revealed decreased level of haemoglobulin, packed cell volume and total erythrocyte count. The serum biochemistry revealed elevated level of liver enzyme Asparate transaminase enzyme. All haemoparasitaemic animals were treated with specific drugs and recovered successfully.

Real time HR-MAS NMR: application in reaction optimization, mechanism elucidation and kinetic analysis for heterogeneous reagent catalyzed small molecule chemistry.

A novel application of in situ (1)H high-resolution magic angle spinning (HR-MAS) NMR technique for real-time monitoring of H(2)SO(4)-silica promoted formation of 2, 2-disubstituted quinozolin-4(3H)-ones is reported. The detailed NMR spectroscopic data led to elucidation of the mechanism, reaction optimization, kinetics and quantitative analysis of the product accurately and efficiently. The translation of the optimized parameters obtained by (1)H HR-MAS NMR in the wet laboratory provided similar results. It is proposed that (1)H HR-MAS has a potential utility for optimization of various organic transformations in solid supported catalyzed reactions.

Acetyl-L-carnitine ameliorates hypobaric hypoxic impairment and spatial memory deficits in rats.

Inadequate oxygen availability at high altitude causes oxidative stress and generation of reactive oxygen species, which may lead to memory impairment. Hippocampus, which plays a key role in the learning and memory processes, is especially vulnerable to hypoxic damage. The present study was aimed at investigating the effect of acetyl-L-carnitine on spatial working and reference memory deficits along with oxidative and apoptotic damage, caused by hypobaric hypoxia in male Sprague Dawley rats. Rats were trained in Morris Water Maze for eight days after which they were submitted to chronic hypobaric hypoxia exposure at a simulated altitude of 6100 m for three days. Rats received daily acetyl-L-carnitine at a dosage of 75 mg/kg body weight orally during exposure. Subsequent to exposure, performance of the animals was tested in Morris Water Maze, which revealed working memory impairment that was significantly improved by acetyl-L-carnitine. However, there was no change in the reference memory after hypobaric hypoxia exposure. Following behavioral study animals were sacrificed and biomarkers of oxidative damage like free radical production, lactate dehydrogenase activity, lipid peroxidation, antioxidant status and expression of apoptotic [viz. caspase-3, Apoptosis activating factor (Apaf-1), bax, cytochrome c] and anti-apoptotic protein-Bcl-2 were studied in the hippocampus. There was a significant increase in oxidative stress along with increased expression of apoptotic proteins and NR1 subunit of glutamate receptor indicating occurrence of excitotoxicity in hypoxia exposed rats. These results suggested that supplementation with acetyl-L-carnitine improves spatial working memory deficits reduces oxidative stress and inhibits apoptotic cascade induced by hypoxia.

N-acetyl cysteine supplementation prevents impairment of spatial working memory functions in rats following exposure to hypobaric hypoxia.

Exposure to high altitude (HA), especially extreme altitude, is associated with impairment of cognitive functions including memory and increased oxidative stress. However, the underlying mechanisms involved are not well understood. It is hypothesized that HA induced oxidative stress may be one of the factors underlying hypoxia induced memory impairment. The aim of the present study was to investigate the effect of hypobaric hypoxia (HH) on spatial working and reference memory functions, oxidative stress markers in rats and effect of supplementation of N-acetyl cysteine (NAC). The rats were divided into four groups. Group I served as normoxic (n=6), Group II served as hypoxic (n=6), Group III as hypoxia group treated with NAC (n=6) and Group IV served as normoxic group treated with NAC (n=6). Group II & III were exposed to HH for 3 days equivalent to 6100 m and received oral NAC supplementation (750 mg/kg) daily. Rats from all the groups were trained in Morris Water Maze (MWM) task for 8 consecutive days. Spatial working and reference memory were tested immediately after the termination of HH and then the rats were sacrificed for estimation of oxidative stress markers in hippocampus. Rats displayed significant deficits in spatial working memory, and increased oxidative stress along with decrease in antioxidant status on hypoxic exposure. Supplementation with NAC in hypoxia-exposed group improved spatial memory performance, and decreased oxidative stress. These findings indicate that hypoxic exposure is associated with increased oxidative stress, which may have caused memory deficit in rats exposed to simulated HA.

Dermatophilus congolensis infection in sheep and goats in Delta region of Tamil Nadu.

AIM: The study was conducted to isolate and identify Dermatophilus congolensis (DC) using conventional and molecular diagnostic techniques in scab materials collected from skin infections of sheep and goats in the Delta region of Tamil Nadu. MATERIALS AND METHODS: A total of 20 scab samples collected from 18 goats and 2 sheep from Nagapattinam, Thanjavur, and Tiruvarur districts of Tamil Nadu. Smears were made from softened scab materials and stained by either Gram's or Giemsa staining. Isolation was attempted on blood agar plates, and colonies were stained by Gram's staining for morphological identification. Identification was also done by biochemical tests and confirmed by 16S rRNA polymerase chain reaction (PCR), followed by sequencing and phylogenetic analysis of the amplified product. RESULTS: The peculiar laddering arrangement of coccoid forms in stained smears prepared from scab materials revealed the presence of DC. Isolated colonies from scab materials of sheep and goats on bovine blood agar plate were small, hemolytic, rough, adherent, and bright orange-yellow in color, but some colonies were white to cream color. Gram-staining of cultured organisms revealed Gram-positive branching filaments with various disintegration stages of organisms. 16S rRNA PCR yielded 500 bp amplicon specific for DC. Sequence analysis of a sheep DC isolate showed 99-100% sequence homology with other DC isolates available in NCBI database, and phylogenetic tree showed a close cluster with DC isolates of Congo, Nigeria, and Angola of Africa. Genes for virulence factors such as serine protease and alkaline ceramidase could not be detected by PCR in any of the DC strains isolated of this study. CONCLUSION: The presence of dermatophilosis in Tamil Nadu was established from this study.

A rare cause of cavitatory pneumonia.

Radiographic findings of thick walled cavities in the lungs are typically seen in mycobacterial infections, malignant lesions, fungal infections, pulmonary vasculitis or other inflammatory lesions of the lungs. Necrotizing infections of the lungs caused by gram negative bacteria (Klebsiella, Psudomonas, Legionella) and Staphylococcus aureus may also form cavities of varying thickness, with consolidation. Escherichia coli pneumonia causing pulmonary cavities is very rare and the few cases reported are of pneumatocele formation. Here we present an unusual case of Escherichia coli infection as a rare cause of bilateral cavitating necrotizing pneumoniae, in a 67 year old male with uncontrolled type 2 diabetes mellitus.

Neuroprotective effect of N-acetyl cysteine on hypoxia-induced oxidative stress in primary hippocampal culture.

Hippocampus has received a considerable attention in the recent past due to its role in a number of important functions such as learning and memory. The effect of hypoxia on neuronal cell injury especially on hippocampal cells is not well known. The aim of the present study was to characterize the biochemical changes in primary cultured hippocampal neurons during hypoxic exposure and the protective effect of N-acetyl cysteine on hypoxia-induced cytotoxicity. The hippocampal culture grown in 24-well plates was exposed to hypoxia for 3 h in a dessicator in 95% N(2), 5% CO(2) atmosphere at 37 degrees C. Later, the cells were allowed to recover for 1 h under normoxia. It was observed that there is an appreciable increase in cytotoxicity in cells exposed to hypoxia. Further, there was a significant decrease in mitochondrial membrane potential and appreciable increase in reactive oxygen species and single-strand DNA breaks in cells exposed to hypoxia compared to control. There is a significant fall in glutathione peroxidase, glutathione reductase, reduced glutathione levels, and nitric oxide in the cells exposed to hypoxia. Significant elevation in the intracellular calcium level in the cells on exposure to hypoxia was observed. Supplementation with NAC (50 microM) resulted in a significant cytoprotection, fall in ROS generation, and higher antioxidant levels similar to that of control cells. NAC also inhibited DNA strand breaks induced by hypoxia. The study indicates that NAC has significant neuroprotective activity during hypoxia in primary hippocampal culture.

A comparative evaluation of medicated calcium sulphate, hydroxylapatite, mineral trioxide aggregate (MTA) as barrier and their effect on the sealing ability of furcation perforation repair material--an in vitro study.

Artificial communication between the root canal system and supporting tissues of the tooth lowers the prognosis of the endodontic treatment. Studies have found that the second most common reason for failure association with endodontic treatment is root perforation. Hence a study was undertaken to evaluate the effect of calcium sulphate, hydroxylapatite and MTA as internal matrix and their ability on the sealing ability of the perforation repair material (GIC) on 70 recently extracted molar with non fused roots. MTA showed the least microleakage and best sealing ability and resin modified GIC when used alone without any internal matrix showed maximum microleakage and least sealing ability.

LED's--future technology in curing scenario?--an in-vitro study.

The long term clinical success of composite restoration depends upon appropriate curing light sources. This in-vitro comparative study investigates the influence of conventional halogen and light emitting diode curing sources on the surface hardness, depth of cure and polymerization shrinkage of composites specimens of 8 mm diameter and 10 mm in height were used to study the depth of cure. Specimens of dimension 8.6 mm in diameter and 2 mm in depth were used to measure the surface hardness and polymerization shrinkage. The results showed that in the long run LED's seem to have great potential to achieve a clinically consistent quality of composite cure.