Titanium dioxide fiber saturable absorber for Q-switched fiber laser generation in the 1-micrometer region: publisher's note.

This publisher's note serves to correct an error in Appl. Opt. 58, 3495 (2019)APOPAI0003-693510.1364/AO.58.003495.

Titanium dioxide fiber saturable absorber for Q-switched fiber laser generation in the 1-micrometer region.

A passively Q-switched ytterbium-doped fiber laser (YDFL) operating at 1062 nm was demonstrated by using a segment of 20 cm titanium dioxide-doped fiber saturable absorber (TiO2DF SA). The Q-switched YDFL emerged stably with tunable repetition rates ranging from 32 kHz to 53 kHz as the pump power rose from 109 mW to 233 mW. Within this range of pump power, a maximum output power of 10.1 mW, maximum peak power of 75 mW, and maximum pulse energy of 191 nJ were obtained. The narrowest pulse width of 2.55 µs was attained at the maximum pump power of 233 mW, while the signal-to-noise ratio of the fundamental frequency was 47 dB. This demonstration reveals that the proposed TiO2DF SA is feasible for constructing a flexible and reliably stable Q-switched pulsed fiber laser in the 1-micrometer region.

Mode-locking pulse generation with MoS2-PVA saturable absorber in both anomalous and ultra-long normal dispersion regimes.

We experimentally demonstrate a stable and simple mode locked erbium doped fiber laser (EDFL) utilizing passive few-layer molybdenum disulfide (MoS2) as a saturable absorber. The MoS2 is obtained by liquid phase exfoliation before it is embedded in a polymer composite film and then inserted in the laser cavity. A stable soliton pulse train started at a low threshold pump power of 20 mW in the anomalous dispersion regime after fine-tuning the rotation of the polarization controller. The central wavelength, 3 dB bandwidth, pulse width, and repetition rate of the soliton pulses are 1574.6 nm, 9.5 nm, 790 fs, and 29.5 MHz, respectively. By inserting a 850 m long dispersion shifted fiber (DSF) in the cavity, a dissipative soliton with square pulse train is obtained in the normal dispersion regime where the operating wavelength is centered at 1567.44 nm with a 3 dB bandwidth of 19.68 nm. The dissipative soliton pulse has a pulse width of 90 ns at a low repetition rate of 231.5 kHz due to the long DSF used. These results are a contribution to the pool of knowledge in nonlinear optical properties of two-dimensional nanomaterials especially for ultrafast photonic applications.

Momordica charantia ointment accelerates diabetic wound healing and enhances transforming growth factor-ß expression.

OBJECTIVE: Transforming growth factor-ß (TGF-ß) plays an important role in wound healing. Delayed wound healing is a consequence of diabetes, leading to high morbidity and poor quality of life. Momordica charantia (MC) fruit possesses anti-diabetic and wound healing properties. This study aimed to explore the changes in TGF-ß expression in diabetic wounds treated with topical MC fruit extract. METHODS: Fifty-six male Sprague-Dawley rats were divided into a normal control group and five diabetic groups of ten rats each. Intravenous streptozotocin (50mg/kg) was given to induce diabetes in the diabetic groups. Full thickness excision wounds were created on the thoracodorsal region of the animals, and these wounds were then treated with vehicle, MC powder, MC ointment and povidone ointment or ointment base for ten days. Wound healing was determined by the rate of wound closure, total protein content and TGF-ß expression in the wounds, and histological observation. RESULTS: Diabetic groups showed delayed wound closure rates compared to the control group. The wound closure rate in the MC ointment group was significantly faster than that of the untreated diabetic group (p<0.05). The MC ointment group also showed intense TGF-ß expression and a high level of total protein content. CONCLUSION: MC ointment has a promising potential for use as an alternative topical medication for diabetic wounds. This work has shown that it accelerates wound healing in diabetic rats, and it is suggested here that this occurs by enhancing TGF-ß expression. Further work is recommended to explore this effect.

Tocotrienol rich fraction (TRF) supplementation protects against oxidative DNA damage and improves cognitive functions in Wistar rats.

AIM: Oxidative stress is caused by imbalance between the productions of reactive oxygen species (ROS) and antioxidant defense mechanisms. Palm oil antioxidants such as tocotrienol rich fraction (TRF) is known to have neuroprotective effects on neurones by acting against free radical induced neuronal cell death. This study was undertaken to elucidate the effect of TRF on oxidative DNA damage and cognitive functions in experimental rats. MATERIALS AND METHODS: A total of 20 male Wistar rats (aged 3 months) were divided into 2 groups: (i) control group fed with distilled water and (ii) experimental group fed with TRF (200 mg/ kg body weight) for 8 months. DNA damage was determined using Comet assay. Antioxidant enzymes like superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were assessed in the blood. The Morris Water Maze (MWM) test was used to evaluate the cognitive functions. RESULTS: DNA damage was significantly reduced in the experimental group supplemented with TRF compared to the control group (p <0.05). In the group supplemented with TRF, the percentage of DNA damage was 2.87 ± 0.48% compared to 5.96 ± 0.43% in the control group. SOD, GPx, and CAT enzyme activities increased in experimental group. Results from MWM showed improvement in cognitive functions as determined by latency to target platform, swim path and average speed between TRF and control groups. CONCLUSIONS: Continuous supplementation of TRF for 8 months reduced DNA damage and exhibited positive influence in spatial learning and memory.

Atlanto-occipital fusion: an osteological study with clinical implications.

BACKGROUND: Atlanto-occipital fusion may be symptomatic or asymptomatic in nature. The anomaly may be incidentally detected at autopsies or during routine cadaveric dissections. The fusion of the atlas with occipital bone may result in the compression of vertebral artery and first cervical nerve. METHODS: A total of 55 dried occipital bones in the Department of Anatomy, Universiti Kebangsaan Malaysia (UKM) and Department of Anatomy, Universiti Malaya (UM) were included in the study. The presence of atlantooccipital fusion was closely observed and morphometric measurements were taken. RESULTS: Out of 55 dried occipital bones studied, we observed atlanto-occiptalization in two bones (3.63 %). A total of 53 occipital bones (96.37 %) did not exhibit any anomalous fusions. Out of the two anomalous atlanto-occiptal fusions, one was complete while the other had unilateral right-sided fusion of the atlas with the occipital bone. CONCLUSION: Atlanto-occipitalization may result in the compression of vertebral artery thereby influencing the blood flow to the brain. Atlanto-occipitalization may also result in compression of the first cervical nerve. The action of the postural muscles on the extensor surface may be affected as a result of this anomaly. The present article discusses the clinical implications of atlanto-occipitalization, which may be beneficial for neurosurgeons, neurologists and radiologists in day-to-day clinical practice (Fig. 3, Ref. 17).

The effect of Piper betel extract on the wound healing process in experimentally induced diabetic rats.

BACKGROUND: Piper betel (PB) possesses antimicrobial, antifungal, antioxidant and wound healing properties due to its powerful antioxidant effect. Diabetes mellitus (DM) is a metabolic disorder which is associated with complications like impaired wound healing, nephropathy and neuropathy. The main aim of the study was to study the wound healing properties of PB. MATERIALS AND METHODS: A total of 33 male Sprague-Dawley rats (250-300 g) were taken and divided into 3 groups: Group I (control) comprising of 14 rats; Group II (diabetic untreated) comprising of 9 rats; Group III (diabetic treated) comprising of 10 rats. After 10 days of acclimatization, the animals were fasted overnight and diabetes was induced by administration of streptozotocin (45 mg/Kg body weight in a single dose, through tail vein) to group II and III animals. Four 6 mm-diameter full thickness skin excision wounds were created and PB extract (50 mg diluted in 0.1 ml of normal saline) was applied locally for 10 days in group III. The group I and II received normal saline (0.1 ml) for 10 days. The total protein content and the wound contraction rate were determined. RESULTS: The wound contraction rate of group III (35.03 +/- 2.96) was higher as compared to group II (18.40 +/- 3.87) with p = 0.014. The total protein content for group III was 106.39 +/- 4.46 as compared to group II (72.86 +/- 12.86) with p = 0.050. CONCLUSION: PB acted as a protective agent in the early phase of wound healing by increasing total protein content and wound contraction rate.

A histological study of the structural changes in the liver of streptozotocin-induced diabetic rats treated with or without Momordica charantia (bitter gourd).

AIM: Diabetic liver is associated with biochemical, physiological and pathological changes. The aim of the present study was to evaluate the histological changes following administration of Momordica charantia (MC) in the streptozotocin (STZ) induced diabetic rats. MATERIALS AND METHODS: Eighteen Sprague-Dawley rats (n=18) were taken for this study. The animals were divided into 3 groups:- non-diabetic (n=6), untreated diabetic (n=6) and diabetic treated with MC extract (n=6). Diabetes was induced in the experimental rats via intravenous injection of streptozotocin (45 mg/kg body weight). MC extract (50 mg/kg body weight) was administered orally to the treated diabetic rats 10 days following induction. The liver tissues were collected on the 10th day following treatment and the histological study was performed using different staining methods which included hematoxylin and eosin (H&E), Verhoeff's van Gieson (VvG) and periodic acid Schiff (PAS). RESULTS: The liver of the diabetic rats showed involvement of the hepatocytes with features of inflammation. The portal triad in the diabetic liver showed extensive involvement in terms of accumulation of mucopolysaccharide deposits. Liver damage in the diabetic animals showed features of healing with administration of the MC extract. CONCLUSIONS: The MC extract due to its antioxidant role may be helpful in reversing the changes in the liver in diabetes mellitus.

The effect of topical extract of Momordica charantia (bitter gourd) on wound healing in nondiabetic rats and in rats with diabetes induced by streptozotocin.

BACKGROUND: Momordica charantia (MC; bitter gourd) is a traditional herb commonly used for its antidiabetic, antioxidant, contraceptive and antibacterial properties. It is also used for the rapid healing of wounds. AIM: To observe the topical effect of MC extract on the wound-healing process in rats with diabetes induced by streptozotocin. METHODS: In total, 72 Sprague-Dawley rats were used for the study. The animals were subdivided into two groups: a nondiabetic group (n = 36) and a group with diabetes induced by streptozotocin (n = 36). Both groups were subdivided further into a nontreated control group (n = 18), and a topically treated group with MC extract administered daily (n = 18). The wound was inflicted with a 6-mm punch-biopsy needle on the dorsal aspect of the thoracolumbar region. The animals were killed on the days 1, 5 and 10 after wound creation. The rate of wound closure and the total protein content was estimated. Histological study of the wound tissue at days 5 and 10 was also performed. RESULTS: The diabetic group exhibited delayed wound healing as compared to the normal group. Interestingly, the diabetic group treated with topical MC extract showed better results than the nontreated group. CONCLUSION: Results show that administration of MC extract improves and accelerates the process of wound healing in diabetic animals.

The sternalis muscle in cadavers: anatomical facts and clinical significance.

The sternalis is an anomalous muscle located in the anterior wall of thorax and several past reports have described its presence with clinical implications. The sternalis muscle may be incidentally detected during routine cadaveric dissections and autopsies. We observed the presence of anomalous sternalis muscle on both sides of the anterior chest wall in 25 cadavers (n = 50), over a span of three years. Out of a 50 cases, we observed a single case of sternalis on the right side of the 55-year-old male cadaver (2%). The sternalis was found to be absent in the rest 49 cases (98%). The sternalis muscle displayed an oblique course in the anterior wall of the thorax. The muscle originated near the seventh costal cartilage extending obliquely upwards to insert into the second costal cartilage close to the sternum. The originating portion of the muscle was located at a distance of 3.5 cm lateral to the mid-sternal plane. The vertical length and the maximum width of the anomalous sternalis muscle measured 9 cm and 1.9 cm, respectively. The fibers of the muscle vertically ascended upwards. No other associated anomalies were observed in the same cadaver. The presence of sternalis muscle is considered to be a rare variation with no earlier studies being performed in the Malaysian population. The anomalous sternalis muscle may be important for reconstructive surgeons performing mastectomy and radiologists interpreting mammograms. Thus, the sternalis muscle may be academically, anthropologically and surgically important.

An unusual case of additional branches of median nerve innervating the corachobrachialis muscle and its clinical implications.

The flexor compartment muscles of the arm comprising of biceps brachii, brachialis and the coracobrachialis are innervated by the musculocutaneous nerve arising from the lateral cord of the brachial plexus. In the present study, we report a case of anomalous innervation of the corachobrachialis muscle on the left side of a 45-year-old male cadaver. The musculocutaneous nerve originated from the lateral cord, as usual and pierced the corachobrachialis muscle. The median nerve was formed by a contribution from both lateral and medial roots, both of which took origin from the lateral and medial cords, respectively. In addition to the usual musculocutaneous nerve which pierced the corachobrachialis muscle and innervated it, two more anomalous branches from the median nerve were observed to innervate the corachobrachialis. The anatomical knowledge of the variations of the innervations of the corachobrachialis muscle may be important not only for surgeons performing coracoid transfer but also for clinicians diagnosing nerve lesions.